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vim squid.conf

#       WELCOME TO SQUID 5.2
#       ----------------------------
#
#       This is the documentation for the Squid configuration file.
#       This documentation can also be found online at:
#               http://www.squid-cache.org/Doc/config/
#
#       You may wish to look at the Squid home page and wiki for the
#       FAQ and other documentation:
#               http://www.squid-cache.org/
#               http://wiki.squid-cache.org/SquidFaq
#               http://wiki.squid-cache.org/ConfigExamples
#
#       This documentation shows what the defaults for various directives
#       happen to be.  If you don't need to change the default, you should
#       leave the line out of your squid.conf in most cases.
#
#       In some cases "none" refers to no default setting at all,
#       while in other cases it refers to the value of the option
#       - the comments for that keyword indicate if this is the case.
#

#  Configuration options can be included using the "include" directive.
#  Include takes a list of files to include. Quoting and wildcards are
#  supported.
#
#  For example,
#
#  include /path/to/included/file/squid.acl.config
#
#  Includes can be nested up to a hard-coded depth of 16 levels.
#  This arbitrary restriction is to prevent recursive include references
#  from causing Squid entering an infinite loop whilst trying to load
#  configuration files.
#
#  Values with byte units
#
#       Squid accepts size units on some size related directives. All
#       such directives are documented with a default value displaying
#       a unit.
#
#       Units accepted by Squid are:
#               bytes - byte
#               KB - Kilobyte (1024 bytes)
#               MB - Megabyte
#               GB - Gigabyte
#
#  Values with time units
#
#       Time-related directives marked with either "time-units" or
#       "time-units-small" accept a time unit. The supported time units are:
#
#               nanosecond (time-units-small only)
#               microsecond (time-units-small only)
#               millisecond
#               second
#               minute
#               hour
#               day
#               week
#               fortnight
#               month - 30 days
#               year - 31557790080 milliseconds (just over 365 days)
#               decade
#
#  Values with spaces, quotes, and other special characters
#
#       Squid supports directive parameters with spaces, quotes, and other
#       special characters. Surround such parameters with "double quotes". Use
#       the configuration_includes_quoted_values directive to enable or
#       disable that support.
#
#       Squid supports reading configuration option parameters from external
#       files using the syntax:
#               parameters("/path/filename")
#       For example:
#               acl allowlist dstdomain parameters("/etc/squid/allowlist.txt")
#
#  Conditional configuration
#
#       If-statements can be used to make configuration directives
#       depend on conditions:
#
#           if <CONDITION>
#               ... regular configuration directives ...
#           [else
#               ... regular configuration directives ...]
#           endif
#
#       The else part is optional. The keywords "if", "else", and "endif"
#       must be typed on their own lines, as if they were regular
#       configuration directives.
#
#       NOTE: An else-if condition is not supported.
#
#       These individual conditions types are supported:
#
#           true
#               Always evaluates to true.
#           false
#               Always evaluates to false.
#           <integer> = <integer>
#               Equality comparison of two integer numbers.
#
#
#  SMP-Related Macros
#
#       The following SMP-related preprocessor macros can be used.
#
#       ${process_name} expands to the current Squid process "name"
#       (e.g., squid1, squid2, or cache1).
#
#       ${process_number} expands to the current Squid process
#       identifier, which is an integer number (e.g., 1, 2, 3) unique
#       across all Squid processes of the current service instance.
#
#       ${service_name} expands into the current Squid service instance
#       name identifier which is provided by -n on the command line.
#
#  Logformat Macros
#
#       Logformat macros can be used in many places outside of the logformat
#       directive. In theory, all of the logformat codes can be used as %macros,
#       where they are supported. In practice, a %macro expands as a dash (-) when
#       the transaction does not yet have enough information and a value is needed.
#
#       There is no definitive list of what tokens are available at the various
#       stages of the transaction.
#
#       And some information may already be available to Squid but not yet
#       committed where the macro expansion code can access it (report
#       such instances!). The macro will be expanded into a single dash
#       ('-') in such cases. Not all macros have been tested.
#

#  TAG: broken_vary_encoding
#       This option is not yet supported by Squid-3.
#Default:
# none

#  TAG: cache_vary
#       This option is not yet supported by Squid-3.
#Default:
# none

#  TAG: error_map
#       This option is not yet supported by Squid-3.
#Default:
# none

#  TAG: external_refresh_check
#       This option is not yet supported by Squid-3.
#Default:
# none

#  TAG: location_rewrite_program
#       This option is not yet supported by Squid-3.
#Default:
# none

#  TAG: refresh_stale_hit
#       This option is not yet supported by Squid-3.
#Default:
# none

#  TAG: dns_v4_first
#       Remove this line. Squid no longer supports preferential treatment of DNS A records.
#Default:
# none

#  TAG: cache_peer_domain
#       Replace with dstdomain ACLs and cache_peer_access.
#Default:
# none

#  TAG: ie_refresh
#       Remove this line. The behaviour enabled by this is no longer needed.
#Default:
# none

#  TAG: sslproxy_cafile
#       Remove this line. Use tls_outgoing_options cafile= instead.
#Default:
# none

#  TAG: sslproxy_capath
#       Remove this line. Use tls_outgoing_options capath= instead.
#Default:
# none

#  TAG: sslproxy_cipher
#       Remove this line. Use tls_outgoing_options cipher= instead.
#Default:
# none

#  TAG: sslproxy_client_certificate
#       Remove this line. Use tls_outgoing_options cert= instead.
#Default:
# none

#  TAG: sslproxy_client_key
#       Remove this line. Use tls_outgoing_options key= instead.
#Default:
# none

#  TAG: sslproxy_flags
#       Remove this line. Use tls_outgoing_options flags= instead.
#Default:
# none

#  TAG: sslproxy_options
#       Remove this line. Use tls_outgoing_options options= instead.
#Default:
# none

#  TAG: sslproxy_version
#       Remove this line. Use tls_outgoing_options options= instead.
#Default:
# none

#  TAG: hierarchy_stoplist
#       Remove this line. Use always_direct or cache_peer_access ACLs instead if you need to prevent cache_peer use.
#Default:
# none

#  TAG: log_access
#       Remove this line. Use acls with access_log directives to control access logging
#Default:
# none

#  TAG: log_icap
#       Remove this line. Use acls with icap_log directives to control icap logging
#Default:
# none

#  TAG: ignore_ims_on_miss
#       Remove this line. The HTTP/1.1 feature is now configured by 'cache_miss_revalidate'.
#Default:
# none

#  TAG: balance_on_multiple_ip
#       Remove this line. Squid performs a 'Happy Eyeballs' algorithm, this multiple-IP algorithm is not longer relevant.
#Default:
# none

#  TAG: chunked_request_body_max_size
#       Remove this line. Squid is now HTTP/1.1 compliant.
#Default:
# none

#  TAG: dns_v4_fallback
#       Remove this line. Squid performs a 'Happy Eyeballs' algorithm, the 'fallback' algorithm is no longer relevant.
#Default:
# none

#  TAG: emulate_httpd_log
#       Replace this with an access_log directive using the format 'common' or 'combined'.
#Default:
# none

#  TAG: forward_log
#       Use a regular access.log with ACL limiting it to MISS events.
#Default:
# none

#  TAG: ftp_list_width
#       Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
#Default:
# none

#  TAG: ignore_expect_100
#       Remove this line. The HTTP/1.1 feature is now fully supported by default.
#Default:
# none

#  TAG: log_fqdn
#       Remove this option from your config. To log FQDN use %>A in the log format.
#Default:
# none

#  TAG: log_ip_on_direct
#       Remove this option from your config. To log server or peer names use %<A in the log format.
#Default:
# none

#  TAG: maximum_single_addr_tries
#       Replaced by connect_retries. The behaviour has changed, please read the documentation before altering.
#Default:
# none

#  TAG: referer_log
#       Replace this with an access_log directive using the format 'referrer'.
#Default:
# none

#  TAG: update_headers
#       Remove this line. The feature is supported by default in storage types where update is implemented.
#Default:
# none

#  TAG: url_rewrite_concurrency
#       Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
#Default:
# none

#  TAG: useragent_log
#       Replace this with an access_log directive using the format 'useragent'.
#Default:
# none

#  TAG: dns_testnames
#       Remove this line. DNS is no longer tested on startup.
#Default:
# none

#  TAG: extension_methods
#       Remove this line. All valid methods for HTTP are accepted by default.
#Default:
# none

#  TAG: zero_buffers
#Default:
# none

#  TAG: incoming_rate
#Default:
# none

#  TAG: server_http11
#       Remove this line. HTTP/1.1 is supported by default.
#Default:
# none

#  TAG: upgrade_http0.9
#       Remove this line. ICY/1.0 streaming protocol is supported by default.
#Default:
# none

#  TAG: zph_local
#       Alter these entries. Use the qos_flows directive instead.
#Default:
# none

#  TAG: header_access
#       Since squid-3.0 replace with request_header_access or reply_header_access
#       depending on whether you wish to match client requests or server replies.
#Default:
# none

#  TAG: httpd_accel_no_pmtu_disc
#       Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
#Default:
# none

#  TAG: wais_relay_host
#       Replace this line with 'cache_peer' configuration.
#Default:
# none

#  TAG: wais_relay_port
#       Replace this line with 'cache_peer' configuration.
#Default:
# none

# OPTIONS FOR SMP
# -----------------------------------------------------------------------------

#  TAG: workers
#       Number of main Squid processes or "workers" to fork and maintain.
#       0: "no daemon" mode, like running "squid -N ..."
#       1: "no SMP" mode, start one main Squid process daemon (default)
#       N: start N main Squid process daemons (i.e., SMP mode)
#
#       In SMP mode, each worker does nearly all what a single Squid daemon
#       does (e.g., listen on http_port and forward HTTP requests).
#Default:
# SMP support disabled.

#  TAG: cpu_affinity_map
#       Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
#
#       Sets 1:1 mapping between Squid processes and CPU cores. For example,
#
#           cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
#
#       affects processes 1 through 4 only and places them on the first
#       four even cores, starting with core #1.
#
#       CPU cores are numbered starting from 1. Requires support for
#       sched_getaffinity(2) and sched_setaffinity(2) system calls.
#
#       Multiple cpu_affinity_map options are merged.
#
#       See also: workers
#Default:
# Let operating system decide.

#  TAG: shared_memory_locking   on|off
#       Whether to ensure that all required shared memory is available by
#       "locking" that shared memory into RAM when Squid starts. The
#       alternative is faster startup time followed by slightly slower
#       performance and, if not enough RAM is actually available during
#       runtime, mysterious crashes.
#
#       SMP Squid uses many shared memory segments. These segments are
#       brought into Squid memory space using an mmap(2) system call. During
#       Squid startup, the mmap() call often succeeds regardless of whether
#       the system has enough RAM. In general, Squid cannot tell whether the
#       kernel applies this "optimistic" memory allocation policy (but
#       popular modern kernels usually use it).
#
#       Later, if Squid attempts to actually access the mapped memory
#       regions beyond what the kernel is willing to allocate, the
#       "optimistic" kernel simply kills Squid kid with a SIGBUS signal.
#       Some of the memory limits enforced by the kernel are currently
#       poorly understood: We do not know how to detect and check them. This
#       option ensures that the mapped memory will be available. 
#
#       This option may have a positive performance side-effect: Locking
#       memory at start avoids runtime paging I/O. Paging slows Squid down.
#
#       Locking memory may require a large enough RLIMIT_MEMLOCK OS limit,
#       CAP_IPC_LOCK capability, or equivalent.
#Default:
# shared_memory_locking off

#  TAG: hopeless_kid_revival_delay      time-units
#       Normally, when a kid process dies, Squid immediately restarts the
#       kid. A kid experiencing frequent deaths is marked as "hopeless" for
#       the duration specified by this directive. Hopeless kids are not
#       automatically restarted.
#
#       Currently, zero values are not supported because they result in
#       misconfigured SMP Squid instances running forever, endlessly
#       restarting each dying kid. To effectively disable hopeless kids
#       revival, set the delay to a huge value (e.g., 1 year).
#
#       Reconfiguration also clears all hopeless kids designations, allowing
#       for manual revival of hopeless kids.
#Default:
# hopeless_kid_revival_delay 1 hour

# OPTIONS FOR AUTHENTICATION
# -----------------------------------------------------------------------------

#  TAG: auth_param
#       This is used to define parameters for the various authentication
#       schemes supported by Squid.
#
#               format: auth_param scheme parameter [setting]
#
#       The order in which authentication schemes are presented to the client is
#       dependent on the order the scheme first appears in config file. IE
#       has a bug (it's not RFC 2617 compliant) in that it will use the basic
#       scheme if basic is the first entry presented, even if more secure
#       schemes are presented. For now use the order in the recommended
#       settings section below. If other browsers have difficulties (don't
#       recognize the schemes offered even if you are using basic) either
#       put basic first, or disable the other schemes (by commenting out their
#       program entry).
#
#       Once an authentication scheme is fully configured, it can only be
#       shutdown by shutting squid down and restarting. Changes can be made on
#       the fly and activated with a reconfigure. I.E. You can change to a
#       different helper, but not unconfigure the helper completely.
#
#       Please note that while this directive defines how Squid processes
#       authentication it does not automatically activate authentication.
#       To use authentication you must in addition make use of ACLs based
#       on login name in http_access (proxy_auth, proxy_auth_regex or
#       external with %LOGIN used in the format tag). The browser will be
#       challenged for authentication on the first such acl encountered
#       in http_access processing and will also be re-challenged for new
#       login credentials if the request is being denied by a proxy_auth
#       type acl.
#
#       WARNING: authentication can't be used in a transparently intercepting
#       proxy as the client then thinks it is talking to an origin server and
#       not the proxy. This is a limitation of bending the TCP/IP protocol to
#       transparently intercepting port 80, not a limitation in Squid.
#       Ports flagged 'transparent', 'intercept', or 'tproxy' have
#       authentication disabled.
#
#       === Parameters common to all schemes. ===
#
#       "program" cmdline
#               Specifies the command for the external authenticator.
#
#               By default, each authentication scheme is not used unless a
#               program is specified.
#
#               See http://wiki.squid-cache.org/Features/AddonHelpers for
#               more details on helper operations and creating your own.
#
#       "key_extras" format
#               Specifies a string to be append to request line format for
#               the authentication helper. "Quoted" format values may contain
#               spaces and logformat %macros. In theory, any logformat %macro
#               can be used. In practice, a %macro expands as a dash (-) if
#               the helper request is sent before the required macro
#               information is available to Squid.
#
#               By default, Squid uses request formats provided in
#               scheme-specific examples below (search for %credentials).
#
#               The expanded key_extras value is added to the Squid credentials
#               cache and, hence, will affect authentication. It can be used to
#               autenticate different users with identical user names (e.g.,
#               when user authentication depends on http_port).
#
#               Avoid adding frequently changing information to key_extras. For
#               example, if you add user source IP, and it changes frequently
#               in your environment, then max_user_ip ACL is going to treat
#               every user+IP combination as a unique "user", breaking the ACL
#               and wasting a lot of memory on those user records. It will also
#               force users to authenticate from scratch whenever their IP
#               changes.
#
#       "realm" string
#               Specifies the protection scope (aka realm name) which is to be
#               reported to the client for the authentication scheme. It is
#               commonly part of the text the user will see when prompted for
#               their username and password.
#
#               For Basic the default is "Squid proxy-caching web server".
#               For Digest there is no default, this parameter is mandatory.
#               For NTLM and Negotiate this parameter is ignored.
#
#       "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
#               [queue-size=N] [on-persistent-overload=action]
#               [reservation-timeout=seconds]
#
#               The maximum number of authenticator processes to spawn. If
#               you start too few Squid will have to wait for them to process
#               a backlog of credential verifications, slowing it down. When
#               password verifications are done via a (slow) network you are
#               likely to need lots of authenticator processes.
#
#               The startup= and idle= options permit some skew in the exact
#               amount run. A minimum of startup=N will begin during startup
#               and reconfigure. Squid will start more in groups of up to
#               idle=N in an attempt to meet traffic needs and to keep idle=N
#               free above those traffic needs up to the maximum.
#
#               The concurrency= option sets the number of concurrent requests
#               the helper can process.  The default of 0 is used for helpers
#               who only supports one request at a time. Setting this to a
#               number greater than 0 changes the protocol used to include a
#               channel ID field first on the request/response line, allowing
#               multiple requests to be sent to the same helper in parallel
#               without waiting for the response.
#
#               Concurrency must not be set unless it's known the helper
#               supports the input format with channel-ID fields.
#
#               The queue-size option sets the maximum number of queued
#               requests. A request is queued when no existing child can
#               accept it due to concurrency limit and no new child can be
#               started due to numberofchildren limit. The default maximum is
#               2*numberofchildren. Squid is allowed to temporarily exceed the
#               configured maximum, marking the affected helper as
#               "overloaded". If the helper overload lasts more than 3
#               minutes, the action prescribed by the on-persistent-overload
#               option applies.
#
#               The on-persistent-overload=action option specifies Squid
#               reaction to a new helper request arriving when the helper
#               has been overloaded for more that 3 minutes already. The number
#               of queued requests determines whether the helper is overloaded
#               (see the queue-size option).
#
#               Two actions are supported:
#
#                 die   Squid worker quits. This is the default behavior.
#
#                 ERR   Squid treats the helper request as if it was
#                       immediately submitted, and the helper immediately
#                       replied with an ERR response. This action has no effect
#                       on the already queued and in-progress helper requests.
#
#               NOTE: NTLM and Negotiate schemes do not support concurrency
#                       in the Squid code module even though some helpers can.
#
#               The reservation-timeout=seconds option allows NTLM and Negotiate
#               helpers to forget about clients that abandon their in-progress
#               connection authentication without closing the connection. The
#               timeout is measured since the last helper response received by
#               Squid for the client. Fractional seconds are not supported.
#
#               After the timeout, the helper will be used for other clients if
#               there are no unreserved helpers available. In the latter case,
#               the old client attempt to resume authentication will not be
#               forwarded to the helper (and the client should open a new HTTP
#               connection and retry authentication from scratch).
#
#               By default, reservations do not expire and clients that keep
#               their connections open without completing authentication may
#               exhaust all NTLM and Negotiate helpers.
#
#       "keep_alive" on|off
#               If you experience problems with PUT/POST requests when using
#               the NTLM or Negotiate schemes then you can try setting this
#               to off. This will cause Squid to forcibly close the connection
#               on the initial request where the browser asks which schemes
#               are supported by the proxy.
#
#               For Basic and Digest this parameter is ignored.
#
#       "utf8" on|off
#               Useful for sending credentials to authentication backends that
#               expect UTF-8 encoding (e.g., LDAP).
#
#               When this option is enabled, Squid uses HTTP Accept-Language
#               request header to guess the received credentials encoding
#               (ISO-Latin-1, CP1251, or UTF-8) and then converts the first
#               two encodings into UTF-8.
#
#               When this option is disabled and by default, Squid sends
#               credentials in their original (i.e. received) encoding.
#
#               This parameter is only honored for Basic and Digest schemes.
#               For Basic, the entire username:password credentials are
#               checked and, if necessary, re-encoded. For Digest -- just the
#               username component. For NTLM and Negotiate schemes, this
#               parameter is ignored.
#
#
#       === Example Configuration ===
#
#       This configuration displays the recommended authentication scheme
#       order from most to least secure with recommended minimum configuration
#       settings for each scheme:
#
##auth_param negotiate program <uncomment and complete this line to activate>
##auth_param negotiate children 20 startup=0 idle=1
##
##auth_param digest program <uncomment and complete this line to activate>
##auth_param digest children 20 startup=0 idle=1
##auth_param digest realm Squid proxy-caching web server
##auth_param digest nonce_garbage_interval 5 minutes
##auth_param digest nonce_max_duration 30 minutes
##auth_param digest nonce_max_count 50
##
##auth_param ntlm program <uncomment and complete this line to activate>
##auth_param ntlm children 20 startup=0 idle=1
##
##auth_param basic program <uncomment and complete this line>
##auth_param basic children 5 startup=5 idle=1
##auth_param basic credentialsttl 2 hours
#Default:
# none

#  TAG: authenticate_cache_garbage_interval
#       The time period between garbage collection across the username cache.
#       This is a trade-off between memory utilization (long intervals - say
#       2 days) and CPU (short intervals - say 1 minute). Only change if you
#       have good reason to.
#Default:
# authenticate_cache_garbage_interval 1 hour

#  TAG: authenticate_ttl
#       The time a user & their credentials stay in the logged in
#       user cache since their last request. When the garbage
#       interval passes, all user credentials that have passed their
#       TTL are removed from memory.
#Default:
# authenticate_ttl 1 hour

#  TAG: authenticate_ip_ttl
#       If you use proxy authentication and the 'max_user_ip' ACL,
#       this directive controls how long Squid remembers the IP
#       addresses associated with each user.  Use a small value
#       (e.g., 60 seconds) if your users might change addresses
#       quickly, as is the case with dialup.   You might be safe
#       using a larger value (e.g., 2 hours) in a corporate LAN
#       environment with relatively static address assignments.
#Default:
# authenticate_ip_ttl 1 second

# ACCESS CONTROLS
# -----------------------------------------------------------------------------

#  TAG: external_acl_type
#       This option defines external acl classes using a helper program
#       to look up the status
#
#         external_acl_type name [options] FORMAT /path/to/helper [helper arguments]
#
#       Options:
#
#         ttl=n         TTL in seconds for cached results (defaults to 3600
#                       for 1 hour)
#
#         negative_ttl=n
#                       TTL for cached negative lookups (default same
#                       as ttl)
#
#         grace=n       Percentage remaining of TTL where a refresh of a
#                       cached entry should be initiated without needing to
#                       wait for a new reply. (default is for no grace period)
#
#         cache=n       The maximum number of entries in the result cache. The
#                       default limit is 262144 entries.  Each cache entry usually
#                       consumes at least 256 bytes. Squid currently does not remove
#                       expired cache entries until the limit is reached, so a proxy
#                       will sooner or later reach the limit. The expanded FORMAT
#                       value is used as the cache key, so if the details in FORMAT
#                       are highly variable, a larger cache may be needed to produce
#                       reduction in helper load.
#
#         children-max=n
#                       Maximum number of acl helper processes spawned to service
#                       external acl lookups of this type. (default 5)
#
#         children-startup=n
#                       Minimum number of acl helper processes to spawn during
#                       startup and reconfigure to service external acl lookups
#                       of this type. (default 0)
#
#         children-idle=n
#                       Number of acl helper processes to keep ahead of traffic
#                       loads. Squid will spawn this many at once whenever load
#                       rises above the capabilities of existing processes.
#                       Up to the value of children-max. (default 1)
#
#         concurrency=n concurrency level per process. Only used with helpers
#                       capable of processing more than one query at a time.
#
#         queue-size=N  The queue-size option sets the maximum number of
#                       queued requests. A request is queued when no existing
#                       helper can accept it due to concurrency limit and no
#                       new helper can be started due to children-max limit.
#                       If the queued requests exceed queue size, the acl is
#                       ignored. The default value is set to 2*children-max.
#
#         protocol=2.5  Compatibility mode for Squid-2.5 external acl helpers.
#
#         ipv4 / ipv6   IP protocol used to communicate with this helper.
#                       The default is to auto-detect IPv6 and use it when available.
#
#
#       FORMAT is a series of %macro codes. See logformat directive for a full list
#       of the accepted codes. Although note that at the time of any external ACL
#       being tested data may not be available and thus some %macro expand to '-'.
#
#       In addition to the logformat codes; when processing external ACLs these
#       additional macros are made available:
#
#         %ACL          The name of the ACL being tested.
#
#         %DATA         The ACL arguments specified in the referencing config
#                       'acl ... external' line, separated by spaces (an
#                       "argument string"). see acl external.
#
#                       If there are no ACL arguments %DATA expands to '-'.
#
#                       If you do not specify a DATA macro inside FORMAT,
#                       Squid automatically appends %DATA to your FORMAT.
#                       Note that Squid-3.x may expand %DATA to whitespace
#                       or nothing in this case.
#
#                       By default, Squid applies URL-encoding to each ACL
#                       argument inside the argument string. If an explicit
#                       encoding modifier is used (e.g., %#DATA), then Squid
#                       encodes the whole argument string as a single token
#                       (e.g., with %#DATA, spaces between arguments become
#                       %20).
#
#       If SSL is enabled, the following formating codes become available:
#
#         %USER_CERT            SSL User certificate in PEM format
#         %USER_CERTCHAIN       SSL User certificate chain in PEM format
#         %USER_CERT_xx         SSL User certificate subject attribute xx
#         %USER_CA_CERT_xx      SSL User certificate issuer attribute xx
#
#
#       NOTE: all other format codes accepted by older Squid versions
#               are deprecated.
#
#
#       General request syntax:
#
#         [channel-ID] FORMAT-values
#
#
#       FORMAT-values consists of transaction details expanded with
#       whitespace separation per the config file FORMAT specification
#       using the FORMAT macros listed above.
#
#       Request values sent to the helper are URL escaped to protect
#       each value in requests against whitespaces.
#
#       If using protocol=2.5 then the request sent to the helper is not
#       URL escaped to protect against whitespace.
#
#       NOTE: protocol=3.0 is deprecated as no longer necessary.
#
#       When using the concurrency= option the protocol is changed by
#       introducing a query channel tag in front of the request/response.
#       The query channel tag is a number between 0 and concurrency-1.
#       This value must be echoed back unchanged to Squid as the first part
#       of the response relating to its request.
#
#
#       The helper receives lines expanded per the above format specification
#       and for each input line returns 1 line starting with OK/ERR/BH result
#       code and optionally followed by additional keywords with more details.
#
#
#       General result syntax:
#
#         [channel-ID] result keyword=value ...
#
#       Result consists of one of the codes:
#
#         OK
#               the ACL test produced a match.
#
#         ERR
#               the ACL test does not produce a match.
#
#         BH
#               An internal error occurred in the helper, preventing
#               a result being identified.
#
#       The meaning of 'a match' is determined by your squid.conf
#       access control configuration. See the Squid wiki for details.
#
#       Defined keywords:
#
#         user=         The users name (login)
#
#         password=     The users password (for login= cache_peer option)
#
#         message=      Message describing the reason for this response.
#                       Available as %o in error pages.
#                       Useful on (ERR and BH results).
#
#         tag=          Apply a tag to a request. Only sets a tag once,
#                       does not alter existing tags.
#
#         log=          String to be logged in access.log. Available as
#                       %ea in logformat specifications.
#
#         clt_conn_tag= Associates a TAG with the client TCP connection.
#                       Please see url_rewrite_program related documentation
#                       for this kv-pair.
#
#       Any keywords may be sent on any response whether OK, ERR or BH.
#
#       All response keyword values need to be a single token with URL
#       escaping, or enclosed in double quotes (") and escaped using \ on
#       any double quotes or \ characters within the value. The wrapping
#       double quotes are removed before the value is interpreted by Squid.
#       \r and \n are also replace by CR and LF.
#
#       Some example key values:
#
#               user=John%20Smith
#               user="John Smith"
#               user="J. \"Bob\" Smith"
#Default:
# none

#  TAG: acl
#       Defining an Access List
#
#       Every access list definition must begin with an aclname and acltype, 
#       followed by either type-specific arguments or a quoted filename that
#       they are read from.
#
#          acl aclname acltype argument ...
#          acl aclname acltype "file" ...
#
#       When using "file", the file should contain one item per line.
#
#
#       ACL Options
#
#       Some acl types supports options which changes their default behaviour:
#
#       -i,+i   By default, regular expressions are CASE-SENSITIVE. To make them
#               case-insensitive, use the -i option. To return case-sensitive
#               use the +i option between patterns, or make a new ACL line
#               without -i.
#
#       -n      Disable lookups and address type conversions.  If lookup or
#               conversion is required because the parameter type (IP or
#               domain name) does not match the message address type (domain
#               name or IP), then the ACL would immediately declare a mismatch
#               without any warnings or lookups.
#
#       -m[=delimiters]
#               Perform a list membership test, interpreting values as
#               comma-separated token lists and matching against individual
#               tokens instead of whole values. 
#               The optional "delimiters" parameter specifies one or more
#               alternative non-alphanumeric delimiter characters.
#               non-alphanumeric delimiter characters.
#
#       --      Used to stop processing all options, in the case the first acl
#               value has '-' character as first character (for example the '-'
#               is a valid domain name)
#
#       Some acl types require suspending the current request in order
#       to access some external data source.
#       Those which do are marked with the tag [slow], those which
#       don't are marked as [fast].
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl
#       for further information
#
#       ***** ACL TYPES AVAILABLE *****
#
#       acl aclname src ip-address/mask ...     # clients IP address [fast]
#       acl aclname src addr1-addr2/mask ...    # range of addresses [fast]
#       acl aclname dst [-n] ip-address/mask ...        # URL host's IP address [slow]
#       acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
#
#if USE_SQUID_EUI
#       acl aclname arp      mac-address ...
#       acl aclname eui64    eui64-address ...
#         # [fast]
#         # MAC (EUI-48) and EUI-64 addresses use xx:xx:xx:xx:xx:xx notation.
#         #
#         # The 'arp' ACL code is not portable to all operating systems.
#         # It works on Linux, Solaris, Windows, FreeBSD, and some other
#         # BSD variants.
#         #
#         # The eui_lookup directive is required to be 'on' (the default)
#         # and Squid built with --enable-eui for MAC/EUI addresses to be
#         # available for this ACL.
#         #
#         # Squid can only determine the MAC/EUI address for IPv4
#         # clients that are on the same subnet. If the client is on a
#         # different subnet, then Squid cannot find out its address.
#         #
#         # IPv6 protocol does not contain ARP. MAC/EUI is either
#         # encoded directly in the IPv6 address or not available.
#endif
#       acl aclname clientside_mark mark[/mask] ...
#         # matches CONNMARK of an accepted connection [fast]
#         # DEPRECATED. Use the 'client_connection_mark' instead.
#
#       acl aclname client_connection_mark mark[/mask] ...
#         # matches CONNMARK of an accepted connection [fast]
#         #
#         # mark and mask are unsigned integers (hex, octal, or decimal).
#         # If multiple marks are given, then the ACL matches if at least
#         # one mark matches.
#         #
#         # Uses netfilter-conntrack library.
#         # Requires building Squid with --enable-linux-netfilter.
#         #
#         # The client, various intermediaries, and Squid itself may set
#         # CONNMARK at various times. The last CONNMARK set wins. This ACL
#         # checks the mark present on an accepted connection or set by
#         # Squid afterwards, depending on the ACL check timing. This ACL
#         # effectively ignores any mark set by other agents after Squid has
#         # accepted the connection.
#
#       acl aclname srcdomain   .foo.com ...
#         # reverse lookup, from client IP [slow]
#       acl aclname dstdomain [-n] .foo.com ...
#         # Destination server from URL [fast]
#       acl aclname srcdom_regex [-i] \.foo\.com ...
#         # regex matching client name [slow]
#       acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
#         # regex matching server [fast]
#         #
#         # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
#         # based URL is used and no match is found. The name "none" is used
#         # if the reverse lookup fails.
#
#       acl aclname src_as number ...
#       acl aclname dst_as number ...
#         # [fast]
#         # Except for access control, AS numbers can be used for
#         # routing of requests to specific caches. Here's an
#         # example for routing all requests for AS#1241 and only
#         # those to mycache.mydomain.net:
#         # acl asexample dst_as 1241
#         # cache_peer_access mycache.mydomain.net allow asexample
#         # cache_peer_access mycache_mydomain.net deny all
#
#       acl aclname peername myPeer ...
#       acl aclname peername_regex [-i] regex-pattern ...
#         # [fast]
#         # match against a named cache_peer entry
#         # set unique name= on cache_peer lines for reliable use.
#
#       acl aclname time [day-abbrevs] [h1:m1-h2:m2]
#         # [fast]
#         #  day-abbrevs:
#         #     S - Sunday
#         #     M - Monday
#         #     T - Tuesday
#         #     W - Wednesday
#         #     H - Thursday
#         #     F - Friday
#         #     A - Saturday
#         #  h1:m1 must be less than h2:m2
#
#       acl aclname url_regex [-i] ^http:// ...
#         # regex matching on whole URL [fast]
#       acl aclname urllogin [-i] [^a-zA-Z0-9] ...
#         # regex matching on URL login field
#       acl aclname urlpath_regex [-i] \.gif$ ...
#         # regex matching on URL path [fast]
#
#       acl aclname port 80 70 21 0-1024...   # destination TCP port [fast]
#                                             # ranges are alloed
#       acl aclname localport 3128 ...        # TCP port the client connected to [fast]
#                                             # NP: for interception mode this is usually '80'
#
#       acl aclname myportname 3128 ...       # *_port name [fast]
#
#       acl aclname proto HTTP FTP ...        # request protocol [fast]
# 
#       acl aclname method GET POST ...       # HTTP request method [fast]
#
#       acl aclname http_status 200 301 500- 400-403 ... 
#         # status code in reply [fast]
#
#       acl aclname browser [-i] regexp ...
#         # pattern match on User-Agent header (see also req_header below) [fast]
#
#       acl aclname referer_regex [-i] regexp ...
#         # pattern match on Referer header [fast]
#         # Referer is highly unreliable, so use with care
#
#       acl aclname ident [-i] username ...
#       acl aclname ident_regex [-i] pattern ...
#         # string match on ident output [slow]
#         # use REQUIRED to accept any non-null ident.
#
#       acl aclname proxy_auth [-i] username ...
#       acl aclname proxy_auth_regex [-i] pattern ...
#         # perform http authentication challenge to the client and match against
#         # supplied credentials [slow]
#         #
#         # takes a list of allowed usernames.
#         # use REQUIRED to accept any valid username.
#         #
#         # Will use proxy authentication in forward-proxy scenarios, and plain
#         # http authenticaiton in reverse-proxy scenarios
#         #
#         # NOTE: when a Proxy-Authentication header is sent but it is not
#         # needed during ACL checking the username is NOT logged
#         # in access.log.
#         #
#         # NOTE: proxy_auth requires a EXTERNAL authentication program
#         # to check username/password combinations (see
#         # auth_param directive).
#         #
#         # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
#         # as the browser needs to be configured for using a proxy in order
#         # to respond to proxy authentication.
#
#       acl aclname snmp_community string ...
#         # A community string to limit access to your SNMP Agent [fast]
#         # Example:
#         #
#         #     acl snmppublic snmp_community public
#
#       acl aclname maxconn number
#         # This will be matched when the client's IP address has
#         # more than <number> TCP connections established. [fast]
#         # NOTE: This only measures direct TCP links so X-Forwarded-For
#         # indirect clients are not counted.
#
#       acl aclname max_user_ip [-s] number
#         # This will be matched when the user attempts to log in from more
#         # than <number> different ip addresses. The authenticate_ip_ttl
#         # parameter controls the timeout on the ip entries. [fast]
#         # If -s is specified the limit is strict, denying browsing
#         # from any further IP addresses until the ttl has expired. Without
#         # -s Squid will just annoy the user by "randomly" denying requests.
#         # (the counter is reset each time the limit is reached and a
#         # request is denied)
#         # NOTE: in acceleration mode or where there is mesh of child proxies,
#         # clients may appear to come from multiple addresses if they are
#         # going through proxy farms, so a limit of 1 may cause user problems.
#
#       acl aclname random probability
#         # Pseudo-randomly match requests. Based on the probability given.
#         # Probability may be written as a decimal (0.333), fraction (1/3)
#         # or ratio of matches:non-matches (3:5).
#
#       acl aclname req_mime_type [-i] mime-type ...
#         # regex match against the mime type of the request generated
#         # by the client. Can be used to detect file upload or some
#         # types HTTP tunneling requests [fast]
#         # NOTE: This does NOT match the reply. You cannot use this
#         # to match the returned file type.
#
#       acl aclname req_header header-name [-i] any\.regex\.here
#         # regex match against any of the known request headers.  May be
#         # thought of as a superset of "browser", "referer" and "mime-type"
#         # ACL [fast]
#
#       acl aclname rep_mime_type [-i] mime-type ...
#         # regex match against the mime type of the reply received by
#         # squid. Can be used to detect file download or some
#         # types HTTP tunneling requests. [fast]
#         # NOTE: This has no effect in http_access rules. It only has
#         # effect in rules that affect the reply data stream such as
#         # http_reply_access.
#
#       acl aclname rep_header header-name [-i] any\.regex\.here
#         # regex match against any of the known reply headers. May be
#         # thought of as a superset of "browser", "referer" and "mime-type"
#         # ACLs [fast]
#
#       acl aclname external class_name [arguments...]
#         # external ACL lookup via a helper class defined by the
#         # external_acl_type directive [slow]
#
#       acl aclname user_cert attribute values...
#         # match against attributes in a user SSL certificate
#         # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
#
#       acl aclname ca_cert attribute values...
#         # match against attributes a users issuing CA SSL certificate
#         # attribute is one of DN/C/O/CN/L/ST or a numerical OID  [fast]
#
#       acl aclname ext_user [-i] username ...
#       acl aclname ext_user_regex [-i] pattern ...
#         # string match on username returned by external acl helper [slow]
#         # use REQUIRED to accept any non-null user name.
#
#       acl aclname tag tagvalue ...
#         # string match on tag returned by external acl helper [fast]
#         # DEPRECATED. Only the first tag will match with this ACL.
#         # Use the 'note' ACL instead for handling multiple tag values.
#
#       acl aclname hier_code codename ...
#         # string match against squid hierarchy code(s); [fast]
#         #  e.g., DIRECT, PARENT_HIT, NONE, etc.
#         #
#         # NOTE: This has no effect in http_access rules. It only has
#         # effect in rules that affect the reply data stream such as
#         # http_reply_access.
#
#       acl aclname note [-m[=delimiters]] name [value ...]
#         # match transaction annotation [fast]
#         # Without values, matches any annotation with a given name.
#         # With value(s), matches any annotation with a given name that
#         # also has one of the given values.
#         # If the -m flag is used, then the value of the named
#         # annotation is interpreted as a list of tokens, and the ACL
#         # matches individual name=token pairs rather than whole
#         # name=value pairs. See "ACL Options" above for more info.
#         # Annotation sources include note and adaptation_meta directives
#         # as well as helper and eCAP responses.
#
#       acl aclname annotate_transaction [-m[=delimiters]] key=value ...
#       acl aclname annotate_transaction [-m[=delimiters]] key+=value ...
#         # Always matches. [fast]
#         # Used for its side effect: This ACL immediately adds a
#         # key=value annotation to the current master transaction.
#         # The added annotation can then be tested using note ACL and
#         # logged (or sent to helpers) using %note format code.
#         #
#         # Annotations can be specified using replacement and addition
#         # formats. The key=value form replaces old same-key annotation
#         # value(s). The key+=value form appends a new value to the old
#         # same-key annotation. Both forms create a new key=value
#         # annotation if no same-key annotation exists already. If
#         # -m flag is used, then the value is interpreted as a list
#         # and the annotation will contain key=token pair(s) instead of the
#         # whole key=value pair.
#         #
#         # This ACL is especially useful for recording complex multi-step
#         # ACL-driven decisions. For example, the following configuration
#         # avoids logging transactions accepted after aclX matched:
#         #
#         #  # First, mark transactions accepted after aclX matched
#         #  acl markSpecial annotate_transaction special=true
#         #  http_access allow acl001
#         #  ...
#         #  http_access deny acl100
#         #  http_access allow aclX markSpecial
#         #
#         #  # Second, do not log marked transactions:
#         #  acl markedSpecial note special true
#         #  access_log ... deny markedSpecial
#         #
#         #  # Note that the following would not have worked because aclX
#         #  # alone does not determine whether the transaction was allowed:
#         #  access_log ... deny aclX # Wrong!
#         #
#         # Warning: This ACL annotates the transaction even when negated
#         # and even if subsequent ACLs fail to match. For example, the
#         # following three rules will have exactly the same effect as far
#         # as annotations set by the "mark" ACL are concerned:
#         #
#         #  some_directive acl1 ... mark # rule matches if mark is reached
#         #  some_directive acl1 ... !mark     # rule never matches
#         #  some_directive acl1 ... mark !all # rule never matches
#
#       acl aclname annotate_client [-m[=delimiters]] key=value ...
#       acl aclname annotate_client [-m[=delimiters]] key+=value ...
#         #
#         # Always matches. [fast]
#         # Used for its side effect: This ACL immediately adds a
#         # key=value annotation to the current client-to-Squid
#         # connection. Connection annotations are propagated to the current
#         # and all future master transactions on the annotated connection.
#         # See the annotate_transaction ACL for details.
#         #
#         # For example, the following configuration avoids rewriting URLs
#         # of transactions bumped by SslBump:
#         #
#         #  # First, mark bumped connections:
#         #  acl markBumped annotate_client bumped=true
#         #  ssl_bump peek acl1
#         #  ssl_bump stare acl2
#         #  ssl_bump bump acl3 markBumped
#         #  ssl_bump splice all
#         #
#         #  # Second, do not send marked transactions to the redirector:
#         #  acl markedBumped note bumped true
#         #  url_rewrite_access deny markedBumped
#         #
#         #  # Note that the following would not have worked because acl3 alone
#         #  # does not determine whether the connection is going to be bumped:
#         #  url_rewrite_access deny acl3 # Wrong!
#
#       acl aclname adaptation_service service ...
#         # Matches the name of any icap_service, ecap_service,
#         # adaptation_service_set, or adaptation_service_chain that Squid
#         # has used (or attempted to use) for the master transaction.
#         # This ACL must be defined after the corresponding adaptation
#         # service is named in squid.conf. This ACL is usable with
#         # adaptation_meta because it starts matching immediately after
#         # the service has been selected for adaptation.
#
#       acl aclname transaction_initiator initiator ...
#         # Matches transaction's initiator [fast]
#         #
#         # Supported initiators are:
#         #  esi: matches transactions fetching ESI resources
#         #  certificate-fetching: matches transactions fetching
#         #     a missing intermediate TLS certificate
#         #  cache-digest: matches transactions fetching Cache Digests
#         #     from a cache_peer
#         #  htcp: matches HTCP requests from peers
#         #  icp: matches ICP requests to peers
#         #  icmp: matches ICMP RTT database (NetDB) requests to peers
#         #  asn: matches asns db requests
#         #  internal: matches any of the above
#         #  client: matches transactions containing an HTTP or FTP
#         #     client request received at a Squid *_port
#         #  all: matches any transaction, including internal transactions
#         #     without a configurable initiator and hopefully rare
#         #     transactions without a known-to-Squid initiator
#         #
#         # Multiple initiators are ORed.
#
#       acl aclname has component
#         # matches a transaction "component" [fast]
#         #
#         # Supported transaction components are:
#         #  request: transaction has a request header (at least)
#         #  response: transaction has a response header (at least)
#         #  ALE: transaction has an internally-generated Access Log Entry
#         #       structure; bugs notwithstanding, all transaction have it
#         #
#         # For example, the following configuration helps when dealing with HTTP
#         # clients that close connections without sending a request header:
#         #
#         #  acl hasRequest has request
#         #  acl logMe note important_transaction
#         #  # avoid "logMe ACL is used in context without an HTTP request" warnings
#         #  access_log ... logformat=detailed hasRequest logMe
#         #  # log request-less transactions, instead of ignoring them
#         #  access_log ... logformat=brief !hasRequest
#         #
#         # Multiple components are not supported for one "acl" rule, but
#         # can be specified (and are ORed) using multiple same-name rules:
#         #
#         #  # OK, this strange logging daemon needs request or response,
#         #  # but can work without either a request or a response:
#         #  acl hasWhatMyLoggingDaemonNeeds has request
#         #  acl hasWhatMyLoggingDaemonNeeds has response
#
#acl aclname at_step step
#         # match against the current request processing step [fast]
#         # Valid steps are:
#         #   GeneratingCONNECT: Generating HTTP CONNECT request headers
#
#       acl aclname any-of acl1 acl2 ...
#         # match any one of the acls [fast or slow]
#         # The first matching ACL stops further ACL evaluation.
#         #
#         # ACLs from multiple any-of lines with the same name are ORed.
#         # For example, A = (a1 or a2) or (a3 or a4) can be written as
#         #   acl A any-of a1 a2
#         #   acl A any-of a3 a4
#         #
#         # This group ACL is fast if all evaluated ACLs in the group are fast
#         # and slow otherwise.
#
#       acl aclname all-of acl1 acl2 ... 
#         # match all of the acls [fast or slow]
#         # The first mismatching ACL stops further ACL evaluation.
#         #
#         # ACLs from multiple all-of lines with the same name are ORed.
#         # For example, B = (b1 and b2) or (b3 and b4) can be written as
#         #   acl B all-of b1 b2
#         #   acl B all-of b3 b4
#         #
#         # This group ACL is fast if all evaluated ACLs in the group are fast
#         # and slow otherwise.
#
#       Examples:
#               acl macaddress arp 09:00:2b:23:45:67
#               acl myexample dst_as 1241
#               acl password proxy_auth REQUIRED
#               acl fileupload req_mime_type -i ^multipart/form-data$
#               acl javascript rep_mime_type -i ^application/x-javascript$
#
#Default:
# ACLs all, manager, localhost, to_localhost, and CONNECT are predefined.
#
#
# Recommended minimum configuration:
#

# Example rule allowing access from your local networks.
# Adapt to list your (internal) IP networks from where browsing
# should be allowed
acl localnet src 0.0.0.1-0.255.255.255  # RFC 1122 "this" network (LAN)
acl localnet src 10.0.0.0/8             # RFC 1918 local private network (LAN)
acl localnet src 100.64.0.0/10          # RFC 6598 shared address space (CGN)
acl localnet src 169.254.0.0/16         # RFC 3927 link-local (directly plugged) machines
acl localnet src 172.16.0.0/12          # RFC 1918 local private network (LAN)
acl localnet src 192.168.0.0/16         # RFC 1918 local private network (LAN)
acl localnet src fc00::/7               # RFC 4193 local private network range
acl localnet src fe80::/10              # RFC 4291 link-local (directly plugged) machines

acl SSL_ports port 443
acl Safe_ports port 80          # http
acl Safe_ports port 21          # ftp
acl Safe_ports port 443         # https
acl Safe_ports port 70          # gopher
acl Safe_ports port 210         # wais
acl Safe_ports port 1025-65535  # unregistered ports
acl Safe_ports port 280         # http-mgmt
acl Safe_ports port 488         # gss-http
acl Safe_ports port 591         # filemaker
acl Safe_ports port 777         # multiling http

#  TAG: proxy_protocol_access
#       Determine which client proxies can be trusted to provide correct
#       information regarding real client IP address using PROXY protocol.
#
#       Requests may pass through a chain of several other proxies
#       before reaching us. The original source details may by sent in:
#               * HTTP message Forwarded header, or
#               * HTTP message X-Forwarded-For header, or
#               * PROXY protocol connection header.
#
#       This directive is solely for validating new PROXY protocol
#       connections received from a port flagged with require-proxy-header.
#       It is checked only once after TCP connection setup.
#
#       A deny match results in TCP connection closure.
#
#       An allow match is required for Squid to permit the corresponding
#       TCP connection, before Squid even looks for HTTP request headers.
#       If there is an allow match, Squid starts using PROXY header information
#       to determine the source address of the connection for all future ACL
#       checks, logging, etc.
#
#       SECURITY CONSIDERATIONS:
#
#               Any host from which we accept client IP details can place
#               incorrect information in the relevant header, and Squid
#               will use the incorrect information as if it were the
#               source address of the request.  This may enable remote
#               hosts to bypass any access control restrictions that are
#               based on the client's source addresses.
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#Default:
# all TCP connections to ports with require-proxy-header will be denied

#  TAG: follow_x_forwarded_for
#       Determine which client proxies can be trusted to provide correct
#       information regarding real client IP address.
#
#       Requests may pass through a chain of several other proxies
#       before reaching us. The original source details may by sent in:
#               * HTTP message Forwarded header, or
#               * HTTP message X-Forwarded-For header, or
#               * PROXY protocol connection header.
#
#       PROXY protocol connections are controlled by the proxy_protocol_access
#       directive which is checked before this.
#
#       If a request reaches us from a source that is allowed by this
#       directive, then we trust the information it provides regarding
#       the IP of the client it received from (if any).
#
#       For the purpose of ACLs used in this directive the src ACL type always
#       matches the address we are testing and srcdomain matches its rDNS.
#
#       On each HTTP request Squid checks for X-Forwarded-For header fields.
#       If found the header values are iterated in reverse order and an allow
#       match is required for Squid to continue on to the next value.
#       The verification ends when a value receives a deny match, cannot be
#       tested, or there are no more values to test.
#       NOTE: Squid does not yet follow the Forwarded HTTP header.
#
#       The end result of this process is an IP address that we will
#       refer to as the indirect client address.  This address may
#       be treated as the client address for access control, ICAP, delay
#       pools and logging, depending on the acl_uses_indirect_client,
#       icap_uses_indirect_client, delay_pool_uses_indirect_client, 
#       log_uses_indirect_client and tproxy_uses_indirect_client options.
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#
#       SECURITY CONSIDERATIONS:
#
#               Any host from which we accept client IP details can place
#               incorrect information in the relevant header, and Squid
#               will use the incorrect information as if it were the
#               source address of the request.  This may enable remote
#               hosts to bypass any access control restrictions that are
#               based on the client's source addresses.
#
#       For example:
#
#               acl localhost src 127.0.0.1
#               acl my_other_proxy srcdomain .proxy.example.com
#               follow_x_forwarded_for allow localhost
#               follow_x_forwarded_for allow my_other_proxy
#Default:
# X-Forwarded-For header will be ignored.

#  TAG: acl_uses_indirect_client        on|off
#       Controls whether the indirect client address
#       (see follow_x_forwarded_for) is used instead of the
#       direct client address in acl matching.
#
#       NOTE: maxconn ACL considers direct TCP links and indirect
#             clients will always have zero. So no match.
#Default:
# acl_uses_indirect_client on

#  TAG: delay_pool_uses_indirect_client on|off
#       Controls whether the indirect client address
#       (see follow_x_forwarded_for) is used instead of the
#       direct client address in delay pools.
#Default:
# delay_pool_uses_indirect_client on

#  TAG: log_uses_indirect_client        on|off
#       Controls whether the indirect client address
#       (see follow_x_forwarded_for) is used instead of the
#       direct client address in the access log.
#Default:
# log_uses_indirect_client on

#  TAG: tproxy_uses_indirect_client     on|off
#       Controls whether the indirect client address
#       (see follow_x_forwarded_for) is used instead of the
#       direct client address when spoofing the outgoing client.
#
#       This has no effect on requests arriving in non-tproxy
#       mode ports.
#
#       SECURITY WARNING: Usage of this option is dangerous
#       and should not be used trivially. Correct configuration
#       of follow_x_forwarded_for with a limited set of trusted
#       sources is required to prevent abuse of your proxy.
#Default:
# tproxy_uses_indirect_client off

#  TAG: spoof_client_ip
#       Control client IP address spoofing of TPROXY traffic based on
#       defined access lists.
#
#       spoof_client_ip allow|deny [!]aclname ...
#
#       If there are no "spoof_client_ip" lines present, the default
#       is to "allow" spoofing of any suitable request.
#
#       Note that the cache_peer "no-tproxy" option overrides this ACL.
#
#       This clause supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#Default:
# Allow spoofing on all TPROXY traffic.

#  TAG: http_access
#       Allowing or Denying access based on defined access lists
#
#       To allow or deny a message received on an HTTP, HTTPS, or FTP port:
#       http_access allow|deny [!]aclname ...
#
#       NOTE on default values:
#
#       If there are no "access" lines present, the default is to deny
#       the request.
#
#       If none of the "access" lines cause a match, the default is the
#       opposite of the last line in the list.  If the last line was
#       deny, the default is allow.  Conversely, if the last line
#       is allow, the default will be deny.  For these reasons, it is a
#       good idea to have an "deny all" entry at the end of your access
#       lists to avoid potential confusion.
#
#       This clause supports both fast and slow acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#
#Default:
# Deny, unless rules exist in squid.conf.
#

#
# Recommended minimum Access Permission configuration:
#
# Deny requests to certain unsafe ports
http_access deny !Safe_ports

# Deny CONNECT to other than secure SSL ports
http_access deny CONNECT !SSL_ports

# Only allow cachemgr access from localhost
http_access allow localhost manager
http_access deny manager

# We strongly recommend the following be uncommented to protect innocent
# web applications running on the proxy server who think the only
# one who can access services on "localhost" is a local user
#http_access deny to_localhost

#
# INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
#
include /etc/squid/conf.d/*.conf

# Example rule allowing access from your local networks.
# Adapt localnet in the ACL section to list your (internal) IP networks
# from where browsing should be allowed
#http_access allow localnet
http_access allow localhost

# And finally deny all other access to this proxy
http_access deny all

#  TAG: adapted_http_access
#       Allowing or Denying access based on defined access lists
#
#       Essentially identical to http_access, but runs after redirectors
#       and ICAP/eCAP adaptation. Allowing access control based on their
#       output.
#
#       If not set then only http_access is used.
#Default:
# Allow, unless rules exist in squid.conf.

#  TAG: http_reply_access
#       Allow replies to client requests. This is complementary to http_access.
#
#       http_reply_access allow|deny [!] aclname ...
#
#       NOTE: if there are no access lines present, the default is to allow
#       all replies.
#
#       If none of the access lines cause a match the opposite of the
#       last line will apply. Thus it is good practice to end the rules
#       with an "allow all" or "deny all" entry.
#
#       This clause supports both fast and slow acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#Default:
# Allow, unless rules exist in squid.conf.

#  TAG: icp_access
#       Allowing or Denying access to the ICP port based on defined
#       access lists
#
#       icp_access  allow|deny [!]aclname ...
#
#       NOTE: The default if no icp_access lines are present is to
#       deny all traffic. This default may cause problems with peers
#       using ICP.
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#
## Allow ICP queries from local networks only
##icp_access allow localnet
##icp_access deny all
#Default:
# Deny, unless rules exist in squid.conf.

#  TAG: htcp_access
#       Allowing or Denying access to the HTCP port based on defined
#       access lists
#
#       htcp_access  allow|deny [!]aclname ...
#
#       See also htcp_clr_access for details on access control for
#       cache purge (CLR) HTCP messages.
#
#       NOTE: The default if no htcp_access lines are present is to
#       deny all traffic. This default may cause problems with peers
#       using the htcp option.
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#
## Allow HTCP queries from local networks only
##htcp_access allow localnet
##htcp_access deny all
#Default:
# Deny, unless rules exist in squid.conf.

#  TAG: htcp_clr_access
#       Allowing or Denying access to purge content using HTCP based
#       on defined access lists.
#       See htcp_access for details on general HTCP access control.
#
#       htcp_clr_access  allow|deny [!]aclname ...
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#
## Allow HTCP CLR requests from trusted peers
#acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
#htcp_clr_access allow htcp_clr_peer
#htcp_clr_access deny all
#Default:
# Deny, unless rules exist in squid.conf.

#  TAG: miss_access
#       Determines whether network access is permitted when satisfying a request.
#
#       For example;
#           to force your neighbors to use you as a sibling instead of
#           a parent.
#
#               acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
#               miss_access deny  !localclients
#               miss_access allow all
#
#       This means only your local clients are allowed to fetch relayed/MISS
#       replies from the network and all other clients can only fetch cached
#       objects (HITs).
#
#       The default for this setting allows all clients who passed the
#       http_access rules to relay via this proxy.
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#Default:
# Allow, unless rules exist in squid.conf.

#  TAG: ident_lookup_access
#       A list of ACL elements which, if matched, cause an ident
#       (RFC 931) lookup to be performed for this request.  For
#       example, you might choose to always perform ident lookups
#       for your main multi-user Unix boxes, but not for your Macs
#       and PCs.  By default, ident lookups are not performed for
#       any requests.
#
#       To enable ident lookups for specific client addresses, you
#       can follow this example:
#
#       acl ident_aware_hosts src 198.168.1.0/24
#       ident_lookup_access allow ident_aware_hosts
#       ident_lookup_access deny all
#
#       Only src type ACL checks are fully supported.  A srcdomain
#       ACL might work at times, but it will not always provide
#       the correct result.
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#Default:
# Unless rules exist in squid.conf, IDENT is not fetched.

#  TAG: reply_body_max_size     size [acl acl...]
#       This option specifies the maximum size of a reply body. It can be
#       used to prevent users from downloading very large files, such as
#       MP3's and movies. When the reply headers are received, the
#       reply_body_max_size lines are processed, and the first line where
#       all (if any) listed ACLs are true is used as the maximum body size
#       for this reply.
#
#       This size is checked twice. First when we get the reply headers,
#       we check the content-length value.  If the content length value exists
#       and is larger than the allowed size, the request is denied and the
#       user receives an error message that says "the request or reply
#       is too large." If there is no content-length, and the reply
#       size exceeds this limit, the client's connection is just closed
#       and they will receive a partial reply.
#
#       WARNING: downstream caches probably can not detect a partial reply
#       if there is no content-length header, so they will cache
#       partial responses and give them out as hits.  You should NOT
#       use this option if you have downstream caches.
#
#       WARNING: A maximum size smaller than the size of squid's error messages
#       will cause an infinite loop and crash squid. Ensure that the smallest
#       non-zero value you use is greater that the maximum header size plus
#       the size of your largest error page.
#
#       If you set this parameter none (the default), there will be
#       no limit imposed.
#
#       Configuration Format is:
#               reply_body_max_size SIZE UNITS [acl ...]
#       ie.
#               reply_body_max_size 10 MB
#
#Default:
# No limit is applied.

#  TAG: on_unsupported_protocol
#       Determines Squid behavior when encountering strange requests at the
#       beginning of an accepted TCP connection or the beginning of a bumped
#       CONNECT tunnel. Controlling Squid reaction to unexpected traffic is
#       especially useful in interception environments where Squid is likely
#       to see connections for unsupported protocols that Squid should either
#       terminate or tunnel at TCP level.
# 
#               on_unsupported_protocol <action> [!]acl ...
# 
#       The first matching action wins. Only fast ACLs are supported.
#
#       Supported actions are:
# 
#       tunnel: Establish a TCP connection with the intended server and
#               blindly shovel TCP packets between the client and server.
#
#       respond: Respond with an error message, using the transfer protocol
#               for the Squid port that received the request (e.g., HTTP
#               for connections intercepted at the http_port). This is the
#               default.
#
#       Squid expects the following traffic patterns:
#
#         http_port: a plain HTTP request
#         https_port: SSL/TLS handshake followed by an [encrypted] HTTP request
#         ftp_port: a plain FTP command (no on_unsupported_protocol support yet!)
#         CONNECT tunnel on http_port: same as https_port
#         CONNECT tunnel on https_port: same as https_port
#
#       Currently, this directive has effect on intercepted connections and
#       bumped tunnels only. Other cases are not supported because Squid
#       cannot know the intended destination of other traffic.
#
#       For example:
#         # define what Squid errors indicate receiving non-HTTP traffic:
#         acl foreignProtocol squid_error ERR_PROTOCOL_UNKNOWN ERR_TOO_BIG
#         # define what Squid errors indicate receiving nothing:
#         acl serverTalksFirstProtocol squid_error ERR_REQUEST_START_TIMEOUT
#         # tunnel everything that does not look like HTTP:
#          on_unsupported_protocol tunnel foreignProtocol
#         # tunnel if we think the client waits for the server to talk first:
#         on_unsupported_protocol tunnel serverTalksFirstProtocol
#         # in all other error cases, just send an HTTP "error page" response:
#         on_unsupported_protocol respond all
#
#       See also: squid_error ACL
#Default:
# Respond with an error message to unidentifiable traffic

#  TAG: auth_schemes
#       Use this directive to customize authentication schemes presence and
#       order in Squid's Unauthorized and Authentication Required responses.
#
#               auth_schemes scheme1,scheme2,... [!]aclname ...
#
#       where schemeN is the name of one of the authentication schemes
#       configured using auth_param directives. At least one scheme name is
#       required. Multiple scheme names are separated by commas. Either
#       avoid whitespace or quote the entire schemes list.
#
#       A special "ALL" scheme name expands to all auth_param-configured
#       schemes in their configuration order. This directive cannot be used
#       to configure Squid to offer no authentication schemes at all.
#
#       The first matching auth_schemes rule determines the schemes order
#       for the current Authentication Required transaction. Note that the
#       future response is not yet available during auth_schemes evaluation.
#
#       If this directive is not used or none of its rules match, then Squid
#       responds with all configured authentication schemes in the order of
#       auth_param directives in the configuration file.
#
#       This directive does not determine when authentication is used or
#       how each authentication scheme authenticates clients.
#
#       The following example sends basic and negotiate authentication
#       schemes, in that order, when requesting authentication of HTTP
#       requests matching the isIE ACL (not shown) while sending all
#       auth_param schemes in their configuration order to other clients:
#
#               auth_schemes basic,negotiate isIE
#               auth_schemes ALL all # explicit default
#
#       This directive supports fast ACLs only.
#
#       See also: auth_param.
#Default:
# use all auth_param schemes in their configuration order

# NETWORK OPTIONS
# -----------------------------------------------------------------------------

#  TAG: http_port
#       Usage:  port [mode] [options]
#               hostname:port [mode] [options]
#               1.2.3.4:port [mode] [options]
#
#       The socket addresses where Squid will listen for HTTP client
#       requests.  You may specify multiple socket addresses.
#       There are three forms: port alone, hostname with port, and
#       IP address with port.  If you specify a hostname or IP
#       address, Squid binds the socket to that specific
#       address. Most likely, you do not need to bind to a specific
#       address, so you can use the port number alone.
#
#       If you are running Squid in accelerator mode, you
#       probably want to listen on port 80 also, or instead.
#
#       The -a command line option may be used to specify additional
#       port(s) where Squid listens for proxy request. Such ports will
#       be plain proxy ports with no options.
#
#       You may specify multiple socket addresses on multiple lines.
#
#       Modes:
#
#          intercept    Support for IP-Layer NAT interception delivering
#                       traffic to this Squid port.
#                       NP: disables authentication on the port.
#
#          tproxy       Support Linux TPROXY (or BSD divert-to) with spoofing
#                       of outgoing connections using the client IP address.
#                       NP: disables authentication on the port.
#
#          accel        Accelerator / reverse proxy mode
#
#          ssl-bump     For each CONNECT request allowed by ssl_bump ACLs,
#                       establish secure connection with the client and with
#                       the server, decrypt HTTPS messages as they pass through
#                       Squid, and treat them as unencrypted HTTP messages,
#                       becoming the man-in-the-middle.
#
#                       The ssl_bump option is required to fully enable
#                       bumping of CONNECT requests.
#
#       Omitting the mode flag causes default forward proxy mode to be used.
#
#
#       Accelerator Mode Options:
#
#          defaultsite=domainname
#                       What to use for the Host: header if it is not present
#                       in a request. Determines what site (not origin server)
#                       accelerators should consider the default.
#
#          no-vhost     Disable using HTTP/1.1 Host header for virtual domain support.
#
#          protocol=    Protocol to reconstruct accelerated and intercepted
#                       requests with. Defaults to HTTP/1.1 for http_port and
#                       HTTPS/1.1 for https_port.
#                       When an unsupported value is configured Squid will
#                       produce a FATAL error.
#                       Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
#
#          vport        Virtual host port support. Using the http_port number
#                       instead of the port passed on Host: headers.
#
#          vport=NN     Virtual host port support. Using the specified port
#                       number instead of the port passed on Host: headers.
#
#          act-as-origin
#                       Act as if this Squid is the origin server.
#                       This currently means generate new Date: and Expires:
#                       headers on HIT instead of adding Age:.
#
#          ignore-cc    Ignore request Cache-Control headers.
#
#                       WARNING: This option violates HTTP specifications if
#                       used in non-accelerator setups.
#
#          allow-direct Allow direct forwarding in accelerator mode. Normally
#                       accelerated requests are denied direct forwarding as if
#                       never_direct was used.
#
#                       WARNING: this option opens accelerator mode to security
#                       vulnerabilities usually only affecting in interception
#                       mode. Make sure to protect forwarding with suitable
#                       http_access rules when using this.
#
#
#       SSL Bump Mode Options:
#           In addition to these options ssl-bump requires TLS/SSL options.
#
#          generate-host-certificates[=<on|off>]
#                       Dynamically create SSL server certificates for the
#                       destination hosts of bumped CONNECT requests.When 
#                       enabled, the cert and key options are used to sign
#                       generated certificates. Otherwise generated
#                       certificate will be selfsigned.
#                       If there is a CA certificate lifetime of the generated 
#                       certificate equals lifetime of the CA certificate. If
#                       generated certificate is selfsigned lifetime is three 
#                       years.
#                       This option is enabled by default when ssl-bump is used.
#                       See the ssl-bump option above for more information.
#
#          dynamic_cert_mem_cache_size=SIZE
#                       Approximate total RAM size spent on cached generated
#                       certificates. If set to zero, caching is disabled. The
#                       default value is 4MB.
#
#       TLS / SSL Options:
#
#          tls-cert=    Path to file containing an X.509 certificate (PEM format)
#                       to be used in the TLS handshake ServerHello.
#
#                       If this certificate is constrained by KeyUsage TLS
#                       feature it must allow HTTP server usage, along with
#                       any additional restrictions imposed by your choice
#                       of options= settings.
#
#                       When OpenSSL is used this file may also contain a
#                       chain of intermediate CA certificates to send in the
#                       TLS handshake.
#
#                       When GnuTLS is used this option (and any paired
#                       tls-key= option) may be repeated to load multiple
#                       certificates for different domains.
#
#                       Also, when generate-host-certificates=on is configured
#                       the first tls-cert= option must be a CA certificate
#                       capable of signing the automatically generated
#                       certificates.
#
#          tls-key=     Path to a file containing private key file (PEM format)
#                       for the previous tls-cert= option.
#
#                       If tls-key= is not specified tls-cert= is assumed to
#                       reference a PEM file containing both the certificate
#                       and private key.
#
#          cipher=      Colon separated list of supported ciphers.
#                       NOTE: some ciphers such as EDH ciphers depend on
#                             additional settings. If those settings are
#                             omitted the ciphers may be silently ignored
#                             by the OpenSSL library.
#
#          options=     Various SSL implementation options. The most important
#                       being:
#
#                           NO_SSLv3    Disallow the use of SSLv3
#
#                           NO_TLSv1    Disallow the use of TLSv1.0
#
#                           NO_TLSv1_1  Disallow the use of TLSv1.1
#
#                           NO_TLSv1_2  Disallow the use of TLSv1.2
#
#                           SINGLE_DH_USE
#                                     Always create a new key when using
#                                     temporary/ephemeral DH key exchanges
#
#                           SINGLE_ECDH_USE
#                                     Enable ephemeral ECDH key exchange.
#                                     The adopted curve should be specified
#                                     using the tls-dh option.
#
#                           NO_TICKET
#                                     Disable use of RFC5077 session tickets.
#                                     Some servers may have problems
#                                     understanding the TLS extension due
#                                     to ambiguous specification in RFC4507.
#
#                           ALL       Enable various bug workarounds
#                                     suggested as "harmless" by OpenSSL
#                                     Be warned that this reduces SSL/TLS
#                                     strength to some attacks.
#
#                       See the OpenSSL SSL_CTX_set_options documentation for a
#                       more complete list.
#
#          clientca=    File containing the list of CAs to use when
#                       requesting a client certificate.
#
#          tls-cafile=  PEM file containing CA certificates to use when verifying
#                       client certificates. If not configured clientca will be
#                       used. May be repeated to load multiple files.
#
#          capath=      Directory containing additional CA certificates
#                       and CRL lists to use when verifying client certificates.
#                       Requires OpenSSL or LibreSSL.
#
#          crlfile=     File of additional CRL lists to use when verifying
#                       the client certificate, in addition to CRLs stored in
#                       the capath. Implies VERIFY_CRL flag below.
#
#          tls-dh=[curve:]file
#                       File containing DH parameters for temporary/ephemeral DH key
#                       exchanges, optionally prefixed by a curve for ephemeral ECDH
#                       key exchanges.
#                       See OpenSSL documentation for details on how to create the
#                       DH parameter file. Supported curves for ECDH can be listed
#                       using the "openssl ecparam -list_curves" command.
#                       WARNING: EDH and EECDH ciphers will be silently disabled if
#                                this option is not set.
#
#          sslflags=    Various flags modifying the use of SSL:
#                           DELAYED_AUTH
#                               Don't request client certificates
#                               immediately, but wait until acl processing
#                               requires a certificate (not yet implemented).
#                           CONDITIONAL_AUTH
#                               Request a client certificate during the TLS
#                               handshake, but ignore certificate absence in
#                               the TLS client Hello. If the client does
#                               supply a certificate, it is validated.
#                           NO_SESSION_REUSE
#                               Don't allow for session reuse. Each connection
#                               will result in a new SSL session.
#                           VERIFY_CRL
#                               Verify CRL lists when accepting client
#                               certificates.
#                           VERIFY_CRL_ALL
#                               Verify CRL lists for all certificates in the
#                               client certificate chain.
#
#          tls-default-ca[=off]
#                       Whether to use the system Trusted CAs. Default is OFF.
#
#          tls-no-npn   Do not use the TLS NPN extension to advertise HTTP/1.1.
#
#          sslcontext=  SSL session ID context identifier.
#
#       Other Options:
#
#          connection-auth[=on|off]
#                       use connection-auth=off to tell Squid to prevent 
#                       forwarding Microsoft connection oriented authentication
#                       (NTLM, Negotiate and Kerberos)
#
#          disable-pmtu-discovery=
#                       Control Path-MTU discovery usage:
#                           off         lets OS decide on what to do (default).
#                           transparent disable PMTU discovery when transparent
#                                       support is enabled.
#                           always      disable always PMTU discovery.
#
#                       In many setups of transparently intercepting proxies
#                       Path-MTU discovery can not work on traffic towards the
#                       clients. This is the case when the intercepting device
#                       does not fully track connections and fails to forward
#                       ICMP must fragment messages to the cache server. If you
#                       have such setup and experience that certain clients
#                       sporadically hang or never complete requests set
#                       disable-pmtu-discovery option to 'transparent'.
#
#          name=        Specifies a internal name for the port. Defaults to
#                       the port specification (port or addr:port)
#
#          tcpkeepalive[=idle,interval,timeout]
#                       Enable TCP keepalive probes of idle connections.
#                       In seconds; idle is the initial time before TCP starts
#                       probing the connection, interval how often to probe, and
#                       timeout the time before giving up.
#
#          require-proxy-header
#                       Require PROXY protocol version 1 or 2 connections.
#                       The proxy_protocol_access is required to permit
#                       downstream proxies which can be trusted.
#
#          worker-queues
#                       Ask TCP stack to maintain a dedicated listening queue
#                       for each worker accepting requests at this port.
#                       Requires TCP stack that supports the SO_REUSEPORT socket
#                       option.
#
#                       SECURITY WARNING: Enabling worker-specific queues
#                       allows any process running as Squid's effective user to
#                       easily accept requests destined to this port.
#
#       If you run Squid on a dual-homed machine with an internal
#       and an external interface we recommend you to specify the
#       internal address:port in http_port. This way Squid will only be
#       visible on the internal address.
#
#

# Squid normally listens to port 3128
http_port 3128

#  TAG: https_port
#       Usage:  [ip:]port [mode] tls-cert=certificate.pem [options]
#
#       The socket address where Squid will listen for client requests made
#       over TLS or SSL connections. Commonly referred to as HTTPS.
#
#       This is most useful for situations where you are running squid in
#       accelerator mode and you want to do the TLS work at the accelerator
#       level.
#
#       You may specify multiple socket addresses on multiple lines,
#       each with their own certificate and/or options.
#
#       The tls-cert= option is mandatory on HTTPS ports.
#
#       See http_port for a list of modes and options.
#Default:
# none

#  TAG: ftp_port
#       Enables Native FTP proxy by specifying the socket address where Squid
#       listens for FTP client requests. See http_port directive for various
#       ways to specify the listening address and mode.
#
#       Usage: ftp_port address [mode] [options]
#
#       WARNING: This is a new, experimental, complex feature that has seen
#       limited production exposure. Some Squid modules (e.g., caching) do not
#       currently work with native FTP proxying, and many features have not
#       even been tested for compatibility. Test well before deploying!
#
#       Native FTP proxying differs substantially from proxying HTTP requests
#       with ftp:// URIs because Squid works as an FTP server and receives
#       actual FTP commands (rather than HTTP requests with FTP URLs).
#
#       Native FTP commands accepted at ftp_port are internally converted or
#       wrapped into HTTP-like messages. The same happens to Native FTP
#       responses received from FTP origin servers. Those HTTP-like messages
#       are shoveled through regular access control and adaptation layers
#       between the FTP client and the FTP origin server. This allows Squid to
#       examine, adapt, block, and log FTP exchanges. Squid reuses most HTTP
#       mechanisms when shoveling wrapped FTP messages. For example,
#       http_access and adaptation_access directives are used.
#
#       Modes:
#
#          intercept    Same as http_port intercept. The FTP origin address is
#                       determined based on the intended destination of the
#                       intercepted connection.
#
#          tproxy       Support Linux TPROXY for spoofing outgoing
#                       connections using the client IP address.
#                       NP: disables authentication and maybe IPv6 on the port.
#
#       By default (i.e., without an explicit mode option), Squid extracts the
#       FTP origin address from the login@origin parameter of the FTP USER
#       command. Many popular FTP clients support such native FTP proxying.
#
#       Options:
#
#          name=token   Specifies an internal name for the port. Defaults to
#                       the port address. Usable with myportname ACL.
#
#          ftp-track-dirs
#                       Enables tracking of FTP directories by injecting extra
#                       PWD commands and adjusting Request-URI (in wrapping
#                       HTTP requests) to reflect the current FTP server
#                       directory. Tracking is disabled by default.
#
#          protocol=FTP Protocol to reconstruct accelerated and intercepted
#                       requests with. Defaults to FTP. No other accepted
#                       values have been tested with. An unsupported value
#                       results in a FATAL error. Accepted values are FTP,
#                       HTTP (or HTTP/1.1), and HTTPS (or HTTPS/1.1).
#
#       Other http_port modes and options that are not specific to HTTP and
#       HTTPS may also work.
#Default:
# none

#  TAG: tcp_outgoing_tos
#       Allows you to select a TOS/Diffserv value for packets outgoing
#       on the server side, based on an ACL.
#
#       tcp_outgoing_tos ds-field [!]aclname ...
#
#       Example where normal_service_net uses the TOS value 0x00
#       and good_service_net uses 0x20
#
#       acl normal_service_net src 10.0.0.0/24
#       acl good_service_net src 10.0.1.0/24
#       tcp_outgoing_tos 0x00 normal_service_net
#       tcp_outgoing_tos 0x20 good_service_net
#
#       TOS/DSCP values really only have local significance - so you should
#       know what you're specifying. For more information, see RFC2474,
#       RFC2475, and RFC3260.
#
#       The TOS/DSCP byte must be exactly that - a octet value  0 - 255, or
#       "default" to use whatever default your host has.
#       Note that only multiples of 4 are usable as the two rightmost bits have
#       been redefined for use by ECN (RFC 3168 section 23.1).
#       The squid parser will enforce this by masking away the ECN bits.
#
#       Processing proceeds in the order specified, and stops at first fully
#       matching line.
#
#       Only fast ACLs are supported.
#Default:
# none

#  TAG: clientside_tos
#       Allows you to select a TOS/DSCP value for packets being transmitted
#       on the client-side, based on an ACL.
#
#       clientside_tos ds-field [!]aclname ...
#
#       Example where normal_service_net uses the TOS value 0x00
#       and good_service_net uses 0x20
#
#       acl normal_service_net src 10.0.0.0/24
#       acl good_service_net src 10.0.1.0/24
#       clientside_tos 0x00 normal_service_net
#       clientside_tos 0x20 good_service_net
#
#       Note: This feature is incompatible with qos_flows. Any TOS values set here
#       will be overwritten by TOS values in qos_flows.
#
#       The TOS/DSCP byte must be exactly that - a octet value  0 - 255, or
#       "default" to use whatever default your host has.
#       Note that only multiples of 4 are usable as the two rightmost bits have
#       been redefined for use by ECN (RFC 3168 section 23.1).
#       The squid parser will enforce this by masking away the ECN bits.
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#Default:
# none

#  TAG: tcp_outgoing_mark
# Note: This option is only available if Squid is rebuilt with the
#       Packet MARK (Linux)
#
#       Allows you to apply a Netfilter mark value to outgoing packets
#       on the server side, based on an ACL.
#
#       tcp_outgoing_mark mark-value [!]aclname ...
#
#       Example where normal_service_net uses the mark value 0x00
#       and good_service_net uses 0x20
#
#       acl normal_service_net src 10.0.0.0/24
#       acl good_service_net src 10.0.1.0/24
#       tcp_outgoing_mark 0x00 normal_service_net
#       tcp_outgoing_mark 0x20 good_service_net
#
#       Only fast ACLs are supported.
#Default:
# none

#  TAG: mark_client_packet
# Note: This option is only available if Squid is rebuilt with the
#       Packet MARK (Linux)
#
#       Allows you to apply a Netfilter MARK value to packets being transmitted
#       on the client-side, based on an ACL.
#
#       mark_client_packet mark-value [!]aclname ...
#
#       Example where normal_service_net uses the MARK value 0x00
#       and good_service_net uses 0x20
#
#       acl normal_service_net src 10.0.0.0/24
#       acl good_service_net src 10.0.1.0/24
#       mark_client_packet 0x00 normal_service_net
#       mark_client_packet 0x20 good_service_net
#
#       Note: This feature is incompatible with qos_flows. Any mark values set here
#       will be overwritten by mark values in qos_flows.
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#Default:
# none

#  TAG: mark_client_connection
# Note: This option is only available if Squid is rebuilt with the
#       Packet MARK (Linux)
#
#       Allows you to apply a Netfilter CONNMARK value to a connection
#       on the client-side, based on an ACL.
#
#       mark_client_connection mark-value[/mask] [!]aclname ...
#
#       The mark-value and mask are unsigned integers (hex, octal, or decimal).
#       The mask may be used to preserve marking previously set by other agents
#       (e.g., iptables).
#
#       A matching rule replaces the CONNMARK value. If a mask is also
#       specified, then the masked bits of the original value are zeroed, and
#       the configured mark-value is ORed with that adjusted value.
#       For example, applying a mark-value 0xAB/0xF to 0x5F CONNMARK, results
#       in a 0xFB marking (rather than a 0xAB or 0x5B).
#
#       This directive semantics is similar to iptables --set-mark rather than
#       --set-xmark functionality.
#
#       The directive does not interfere with qos_flows (which uses packet MARKs,
#       not CONNMARKs).
#
#       Example where squid marks intercepted FTP connections:
#
#       acl proto_ftp proto FTP
#       mark_client_connection 0x200/0xff00 proto_ftp
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#Default:
# none

#  TAG: qos_flows
#       Allows you to select a TOS/DSCP value to mark outgoing
#       connections to the client, based on where the reply was sourced.
#       For platforms using netfilter, allows you to set a netfilter mark
#       value instead of, or in addition to, a TOS value.
#
#       By default this functionality is disabled. To enable it with the default
#       settings simply use "qos_flows mark" or "qos_flows tos". Default
#       settings will result in the netfilter mark or TOS value being copied
#       from the upstream connection to the client. Note that it is the connection
#       CONNMARK value not the packet MARK value that is copied.
#
#       It is not currently possible to copy the mark or TOS value from the
#       client to the upstream connection request.
#
#       TOS values really only have local significance - so you should
#       know what you're specifying. For more information, see RFC2474,
#       RFC2475, and RFC3260.
#
#       The TOS/DSCP byte must be exactly that - a octet value  0 - 255.
#       Note that only multiples of 4 are usable as the two rightmost bits have
#       been redefined for use by ECN (RFC 3168 section 23.1).
#       The squid parser will enforce this by masking away the ECN bits.
#
#       Mark values can be any unsigned 32-bit integer value.
#
#       This setting is configured by setting the following values:
#
#       tos|mark                Whether to set TOS or netfilter mark values
#
#       local-hit=0xFF          Value to mark local cache hits.
#
#       sibling-hit=0xFF        Value to mark hits from sibling peers.
#
#       parent-hit=0xFF         Value to mark hits from parent peers.
#
#       miss=0xFF[/mask]        Value to mark cache misses. Takes precedence
#                               over the preserve-miss feature (see below), unless
#                               mask is specified, in which case only the bits
#                               specified in the mask are written.
#
#       The TOS variant of the following features are only possible on Linux
#       and require your kernel to be patched with the TOS preserving ZPH
#       patch, available from http://zph.bratcheda.org
#       No patch is needed to preserve the netfilter mark, which will work
#       with all variants of netfilter.
#
#       disable-preserve-miss
#               This option disables the preservation of the TOS or netfilter
#               mark. By default, the existing TOS or netfilter mark value of
#               the response coming from the remote server will be retained
#               and masked with miss-mark.
#               NOTE: in the case of a netfilter mark, the mark must be set on
#               the connection (using the CONNMARK target) not on the packet
#               (MARK target).
#
#       miss-mask=0xFF
#               Allows you to mask certain bits in the TOS or mark value
#               received from the remote server, before copying the value to
#               the TOS sent towards clients.
#               Default for tos: 0xFF (TOS from server is not changed).
#               Default for mark: 0xFFFFFFFF (mark from server is not changed).
#
#       All of these features require the --enable-zph-qos compilation flag
#       (enabled by default). Netfilter marking also requires the
#       libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
#       libcap 2.09+ (--with-libcap).
#
#Default:
# none

#  TAG: tcp_outgoing_address
#       Allows you to map requests to different outgoing IP addresses
#       based on the username or source address of the user making
#       the request.
#
#       tcp_outgoing_address ipaddr [[!]aclname] ...
#
#       For example;
#               Forwarding clients with dedicated IPs for certain subnets.
#
#         acl normal_service_net src 10.0.0.0/24
#         acl good_service_net src 10.0.2.0/24
#
#         tcp_outgoing_address 2001:db8::c001 good_service_net
#         tcp_outgoing_address 10.1.0.2 good_service_net
#
#         tcp_outgoing_address 2001:db8::beef normal_service_net
#         tcp_outgoing_address 10.1.0.1 normal_service_net
#
#         tcp_outgoing_address 2001:db8::1
#         tcp_outgoing_address 10.1.0.3
#
#       Processing proceeds in the order specified, and stops at first fully
#       matching line.
#
#       Squid will add an implicit IP version test to each line.
#       Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
#       Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
#
#
#       NOTE: The use of this directive using client dependent ACLs is
#       incompatible with the use of server side persistent connections. To
#       ensure correct results it is best to set server_persistent_connections
#       to off when using this directive in such configurations.
#
#       NOTE: The use of this directive to set a local IP on outgoing TCP links
#       is incompatible with using TPROXY to set client IP out outbound TCP links.
#       When needing to contact peers use the no-tproxy cache_peer option and the
#       client_dst_passthru directive re-enable normal forwarding such as this.
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#Default:
# Address selection is performed by the operating system.

#  TAG: host_verify_strict
#       Regardless of this option setting, when dealing with intercepted
#       traffic, Squid always verifies that the destination IP address matches
#       the Host header domain or IP (called 'authority form URL').
#
#       This enforcement is performed to satisfy a MUST-level requirement in
#       RFC 2616 section 14.23: "The Host field value MUST represent the naming
#       authority of the origin server or gateway given by the original URL".
#
#       When set to ON:
#               Squid always responds with an HTTP 409 (Conflict) error
#               page and logs a security warning if there is no match.
#
#               Squid verifies that the destination IP address matches
#               the Host header for forward-proxy and reverse-proxy traffic
#               as well. For those traffic types, Squid also enables the
#               following checks, comparing the corresponding Host header
#               and Request-URI components:
#
#                * The host names (domain or IP) must be identical,
#                  but valueless or missing Host header disables all checks.
#                  For the two host names to match, both must be either IP
#                  or FQDN.
#
#                * Port numbers must be identical, but if a port is missing
#                  the scheme-default port is assumed.
#
#
#       When set to OFF (the default):
#               Squid allows suspicious requests to continue but logs a
#               security warning and blocks caching of the response.
#
#                * Forward-proxy traffic is not checked at all.
#
#                * Reverse-proxy traffic is not checked at all.
#
#                * Intercepted traffic which passes verification is handled
#                  according to client_dst_passthru.
#
#                * Intercepted requests which fail verification are sent
#                  to the client original destination instead of DIRECT.
#                  This overrides 'client_dst_passthru off'.
#
#               For now suspicious intercepted CONNECT requests are always
#               responded to with an HTTP 409 (Conflict) error page.
#
#
#       SECURITY NOTE:
#
#       As described in CVE-2009-0801 when the Host: header alone is used
#       to determine the destination of a request it becomes trivial for
#       malicious scripts on remote websites to bypass browser same-origin
#       security policy and sandboxing protections.
#
#       The cause of this is that such applets are allowed to perform their
#       own HTTP stack, in which case the same-origin policy of the browser
#       sandbox only verifies that the applet tries to contact the same IP
#       as from where it was loaded at the IP level. The Host: header may
#       be different from the connected IP and approved origin.
#
#Default:
# host_verify_strict off

#  TAG: client_dst_passthru
#       With NAT or TPROXY intercepted traffic Squid may pass the request
#       directly to the original client destination IP or seek a faster
#       source using the HTTP Host header.
#
#       Using Host to locate alternative servers can provide faster
#       connectivity with a range of failure recovery options.
#       But can also lead to connectivity trouble when the client and
#       server are attempting stateful interactions unaware of the proxy.
#
#       This option (on by default) prevents alternative DNS entries being
#       located to send intercepted traffic DIRECT to an origin server.
#       The clients original destination IP and port will be used instead.
#
#       Regardless of this option setting, when dealing with intercepted
#       traffic Squid will verify the Host: header and any traffic which
#       fails Host verification will be treated as if this option were ON.
#
#       see host_verify_strict for details on the verification process.
#Default:
# client_dst_passthru on

# TLS OPTIONS
# -----------------------------------------------------------------------------

#  TAG: tls_outgoing_options
#       disable         Do not support https:// URLs.
#
#       cert=/path/to/client/certificate
#                       A client X.509 certificate to use when connecting.
#
#       key=/path/to/client/private_key
#                       The private key corresponding to the cert= above.
#
#                       If key= is not specified cert= is assumed to
#                       reference a PEM file containing both the certificate
#                       and private key.
#
#       cipher=...      The list of valid TLS ciphers to use.
#
#       min-version=1.N
#                       The minimum TLS protocol version to permit.
#                       To control SSLv3 use the options= parameter.
#                       Supported Values: 1.0 (default), 1.1, 1.2, 1.3
#
#       options=...     Specify various TLS/SSL implementation options.
#
#                       OpenSSL options most important are:
#
#                           NO_SSLv3    Disallow the use of SSLv3
#
#                           SINGLE_DH_USE
#                                     Always create a new key when using
#                                     temporary/ephemeral DH key exchanges
#
#                           NO_TICKET
#                                     Disable use of RFC5077 session tickets.
#                                     Some servers may have problems
#                                     understanding the TLS extension due
#                                     to ambiguous specification in RFC4507.
#
#                           ALL       Enable various bug workarounds
#                                     suggested as "harmless" by OpenSSL
#                                     Be warned that this reduces SSL/TLS
#                                     strength to some attacks.
#
#                               See the OpenSSL SSL_CTX_set_options documentation
#                               for a more complete list.
#
#                       GnuTLS options most important are:
#
#                           %NO_TICKETS
#                                     Disable use of RFC5077 session tickets.
#                                     Some servers may have problems
#                                     understanding the TLS extension due
#                                     to ambiguous specification in RFC4507.
#
#                               See the GnuTLS Priority Strings documentation
#                               for a more complete list.
#                               http://www.gnutls.org/manual/gnutls.html#Priority-Strings
#
#
#       cafile=         PEM file containing CA certificates to use when verifying
#                       the peer certificate. May be repeated to load multiple files.
#
#       capath=         A directory containing additional CA certificates to
#                       use when verifying the peer certificate.
#                       Requires OpenSSL or LibreSSL.
#
#       crlfile=...     A certificate revocation list file to use when
#                       verifying the peer certificate.
#
#       flags=...       Specify various flags modifying the TLS implementation:
#
#                       DONT_VERIFY_PEER
#                               Accept certificates even if they fail to
#                               verify.
#                       DONT_VERIFY_DOMAIN
#                               Don't verify the peer certificate
#                               matches the server name
#
#       default-ca[=off]
#                       Whether to use the system Trusted CAs. Default is ON.
#
#       domain=         The peer name as advertised in its certificate.
#                       Used for verifying the correctness of the received peer
#                       certificate. If not specified the peer hostname will be
#                       used.
#Default:
# tls_outgoing_options min-version=1.0

# SSL OPTIONS
# -----------------------------------------------------------------------------

#  TAG: ssl_unclean_shutdown
# Note: This option is only available if Squid is rebuilt with the
#       --with-openssl
#
#       Some browsers (especially MSIE) bugs out on SSL shutdown
#       messages.
#Default:
# ssl_unclean_shutdown off

#  TAG: ssl_engine
# Note: This option is only available if Squid is rebuilt with the
#       --with-openssl
#
#       The OpenSSL engine to use. You will need to set this if you
#       would like to use hardware SSL acceleration for example.
#
#       Note: OpenSSL 3.0 and newer do not provide Engine support.
#Default:
# none

#  TAG: sslproxy_session_ttl
# Note: This option is only available if Squid is rebuilt with the
#       --with-openssl
#
#       Sets the timeout value for SSL sessions
#Default:
# sslproxy_session_ttl 300

#  TAG: sslproxy_session_cache_size
# Note: This option is only available if Squid is rebuilt with the
#       --with-openssl
#
#        Sets the cache size to use for ssl session
#Default:
# sslproxy_session_cache_size 2 MB

#  TAG: sslproxy_foreign_intermediate_certs
# Note: This option is only available if Squid is rebuilt with the
#       --with-openssl
#
#       Many origin servers fail to send their full server certificate
#       chain for verification, assuming the client already has or can
#       easily locate any missing intermediate certificates.
#
#       Squid uses the certificates from the specified file to fill in
#       these missing chains when trying to validate origin server
#       certificate chains.
#
#       The file is expected to contain zero or more PEM-encoded
#       intermediate certificates. These certificates are not treated
#       as trusted root certificates, and any self-signed certificate in
#       this file will be ignored.
#Default:
# none

#  TAG: sslproxy_cert_sign_hash
# Note: This option is only available if Squid is rebuilt with the
#       --with-openssl
#
#       Sets the hashing algorithm to use when signing generated certificates.
#       Valid algorithm names depend on the OpenSSL library used. The following
#       names are usually available: sha1, sha256, sha512, and md5. Please see
#       your OpenSSL library manual for the available hashes. By default, Squids
#       that support this option use sha256 hashes.
#
#       Squid does not forcefully purge cached certificates that were generated
#       with an algorithm other than the currently configured one. They remain
#       in the cache, subject to the regular cache eviction policy, and become
#       useful if the algorithm changes again.
#Default:
# none

#  TAG: ssl_bump
# Note: This option is only available if Squid is rebuilt with the
#       --with-openssl
#
#       This option is consulted when a CONNECT request is received on
#       an http_port (or a new connection is intercepted at an
#       https_port), provided that port was configured with an ssl-bump
#       flag. The subsequent data on the connection is either treated as
#       HTTPS and decrypted OR tunneled at TCP level without decryption,
#       depending on the first matching bumping "action".
#
#       ssl_bump <action> [!]acl ...
#
#       The following bumping actions are currently supported:
#
#           splice
#               Become a TCP tunnel without decrypting proxied traffic.
#               This is the default action.
#
#           bump
#               When used on step SslBump1, establishes a secure connection
#               with the client first, then connect to the server.
#               When used on step SslBump2 or SslBump3, establishes a secure
#               connection with the server and, using a mimicked server
#               certificate, with the client.
#
#           peek
#               Receive client (step SslBump1) or server (step SslBump2)
#               certificate while preserving the possibility of splicing the
#               connection. Peeking at the server certificate (during step 2)
#               usually precludes bumping of the connection at step 3.
#
#           stare
#               Receive client (step SslBump1) or server (step SslBump2)
#               certificate while preserving the possibility of bumping the
#               connection. Staring at the server certificate (during step 2)
#               usually precludes splicing of the connection at step 3.
#
#           terminate
#               Close client and server connections.
#
#       Backward compatibility actions available at step SslBump1:
#
#           client-first
#               Bump the connection. Establish a secure connection with the
#               client first, then connect to the server. This old mode does
#               not allow Squid to mimic server SSL certificate and does not
#               work with intercepted SSL connections.
#
#           server-first
#               Bump the connection. Establish a secure connection with the
#               server first, then establish a secure connection with the
#               client, using a mimicked server certificate. Works with both
#               CONNECT requests and intercepted SSL connections, but does
#               not allow to make decisions based on SSL handshake info.
#
#           peek-and-splice
#               Decide whether to bump or splice the connection based on 
#               client-to-squid and server-to-squid SSL hello messages.
#               XXX: Remove.
#
#           none
#               Same as the "splice" action.
#
#       All ssl_bump rules are evaluated at each of the supported bumping
#       steps.  Rules with actions that are impossible at the current step are
#       ignored. The first matching ssl_bump action wins and is applied at the
#       end of the current step. If no rules match, the splice action is used.
#       See the at_step ACL for a list of the supported SslBump steps.
#
#       This clause supports both fast and slow acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#
#       See also: http_port ssl-bump, https_port ssl-bump, and acl at_step.
#
#
#       # Example: Bump all TLS connections except those originating from
#       # localhost or those going to example.com.
#
#       acl broken_sites ssl::server_name .example.com
#       ssl_bump splice localhost
#       ssl_bump splice broken_sites
#       ssl_bump bump all
#Default:
# Become a TCP tunnel without decrypting proxied traffic.

#  TAG: sslproxy_cert_error
# Note: This option is only available if Squid is rebuilt with the
#       --with-openssl
#
#       Use this ACL to bypass server certificate validation errors.
#
#       For example, the following lines will bypass all validation errors
#       when talking to servers for example.com. All other
#       validation errors will result in ERR_SECURE_CONNECT_FAIL error.
#
#               acl BrokenButTrustedServers dstdomain example.com
#               sslproxy_cert_error allow BrokenButTrustedServers
#               sslproxy_cert_error deny all
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#       Using slow acl types may result in server crashes
#
#       Without this option, all server certificate validation errors
#       terminate the transaction to protect Squid and the client.
#
#       SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
#       but should not happen unless your OpenSSL library is buggy.
#
#       SECURITY WARNING:
#               Bypassing validation errors is dangerous because an
#               error usually implies that the server cannot be trusted
#               and the connection may be insecure.
#
#       See also: sslproxy_flags and DONT_VERIFY_PEER.
#Default:
# Server certificate errors terminate the transaction.

#  TAG: sslproxy_cert_sign
# Note: This option is only available if Squid is rebuilt with the
#       --with-openssl
#
#
#        sslproxy_cert_sign <signing algorithm> acl ...
#
#        The following certificate signing algorithms are supported:
#
#          signTrusted
#               Sign using the configured CA certificate which is usually
#               placed in and trusted by end-user browsers. This is the
#               default for trusted origin server certificates.
#
#          signUntrusted
#               Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
#               This is the default for untrusted origin server certificates
#               that are not self-signed (see ssl::certUntrusted).
#
#          signSelf
#               Sign using a self-signed certificate with the right CN to
#               generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
#               browser. This is the default for self-signed origin server
#               certificates (see ssl::certSelfSigned).
#
#       This clause only supports fast acl types.
#
#       When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
#       signing algorithm to generate the certificate and ignores all
#       subsequent sslproxy_cert_sign options (the first match wins). If no
#       acl(s) match, the default signing algorithm is determined by errors
#       detected when obtaining and validating the origin server certificate.
#
#       WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
#       be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
#       CONNECT request that carries a domain name. In all other cases (CONNECT
#       to an IP address or an intercepted SSL connection), Squid cannot detect
#       the domain mismatch at certificate generation time when
#       bump-server-first is used.
#Default:
# none

#  TAG: sslproxy_cert_adapt
# Note: This option is only available if Squid is rebuilt with the
#       --with-openssl
#
#
#       sslproxy_cert_adapt <adaptation algorithm> acl ...
#
#       The following certificate adaptation algorithms are supported:
#
#          setValidAfter
#               Sets the "Not After" property to the "Not After" property of
#               the CA certificate used to sign generated certificates.
#
#          setValidBefore
#               Sets the "Not Before" property to the "Not Before" property of
#               the CA certificate used to sign generated certificates.
#
#          setCommonName or setCommonName{CN}
#               Sets Subject.CN property to the host name specified as a 
#               CN parameter or, if no explicit CN parameter was specified,
#               extracted from the CONNECT request. It is a misconfiguration
#               to use setCommonName without an explicit parameter for
#               intercepted or tproxied SSL connections.
#
#       This clause only supports fast acl types.
#
#       Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
#       Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
#       corresponding adaptation algorithm to generate the certificate and
#       ignores all subsequent sslproxy_cert_adapt options in that algorithm's
#       group (i.e., the first match wins within each algorithm group). If no
#       acl(s) match, the default mimicking action takes place.
#
#       WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
#       be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
#       CONNECT request that carries a domain name. In all other cases (CONNECT
#       to an IP address or an intercepted SSL connection), Squid cannot detect
#       the domain mismatch at certificate generation time when
#       bump-server-first is used.
#Default:
# none

#  TAG: sslpassword_program
# Note: This option is only available if Squid is rebuilt with the
#       --with-openssl
#
#       Specify a program used for entering SSL key passphrases
#       when using encrypted SSL certificate keys. If not specified
#       keys must either be unencrypted, or Squid started with the -N
#       option to allow it to query interactively for the passphrase.
#
#       The key file name is given as argument to the program allowing
#       selection of the right password if you have multiple encrypted
#       keys.
#Default:
# none

# OPTIONS RELATING TO EXTERNAL SSL_CRTD 
# -----------------------------------------------------------------------------

#  TAG: sslcrtd_program
# Note: This option is only available if Squid is rebuilt with the
#       --enable-ssl-crtd
#
#       Specify the location and options of the executable for certificate
#       generator.
#
#       /usr/lib/squid/security_file_certgen program can use a disk cache to improve response
#       times on repeated requests. To enable caching, specify -s and -M
#       parameters. If those parameters are not given, the program generates
#       a new certificate on every request.
#
#       For more information use:
#               /usr/lib/squid/security_file_certgen -h
#Default:
# sslcrtd_program /usr/lib/squid/security_file_certgen -s /var/spool/squid/ssl_db -M 4MB

#  TAG: sslcrtd_children
# Note: This option is only available if Squid is rebuilt with the
#       --enable-ssl-crtd
#
#       Specifies the maximum number of certificate generation processes that
#       Squid may spawn (numberofchildren) and several related options. Using
#       too few of these helper processes (a.k.a. "helpers") creates request
#       queues. Using too many helpers wastes your system resources. Squid
#       does not support spawning more than 32 helpers.
#
#       Usage: numberofchildren [option]...
#
#       The startup= and idle= options allow some measure of skew in your
#       tuning.
#
#               startup=N
#
#       Sets the minimum number of processes to spawn when Squid
#       starts or reconfigures. When set to zero the first request will
#       cause spawning of the first child process to handle it.
#
#       Starting too few children temporary slows Squid under load while it
#       tries to spawn enough additional processes to cope with traffic.
#
#               idle=N
#
#       Sets a minimum of how many processes Squid is to try and keep available
#       at all times. When traffic begins to rise above what the existing
#       processes can handle this many more will be spawned up to the maximum
#       configured. A minimum setting of 1 is required.
#
#               queue-size=N
#
#       Sets the maximum number of queued requests. A request is queued when
#       no existing child is idle and no new child can be started due to
#       numberofchildren limit. If the queued requests exceed queue size for
#       more than 3 minutes squid aborts its operation. The default value is
#       set to 2*numberofchildren.
#
#       You must have at least one ssl_crtd process.
#Default:
# sslcrtd_children 32 startup=5 idle=1

#  TAG: sslcrtvalidator_program
# Note: This option is only available if Squid is rebuilt with the
#       --with-openssl
#
#       Specify the location and options of the executable for ssl_crt_validator
#       process.
#
#       Usage:  sslcrtvalidator_program [ttl=n] [cache=n] path ...
#
#       Options:
#         ttl=n         TTL in seconds for cached results. The default is 60 secs
#         cache=n       limit the result cache size. The default value is 2048
#Default:
# none

#  TAG: sslcrtvalidator_children
# Note: This option is only available if Squid is rebuilt with the
#       --with-openssl
#
#       Specifies the maximum number of certificate validation processes that
#       Squid may spawn (numberofchildren) and several related options. Using
#       too few of these helper processes (a.k.a. "helpers") creates request
#       queues. Using too many helpers wastes your system resources. Squid
#       does not support spawning more than 32 helpers.
#
#       Usage: numberofchildren [option]...
#
#       The startup= and idle= options allow some measure of skew in your
#       tuning.
#
#               startup=N
#
#       Sets the minimum number of processes to spawn when Squid
#       starts or reconfigures. When set to zero the first request will
#       cause spawning of the first child process to handle it.
#
#       Starting too few children temporary slows Squid under load while it
#       tries to spawn enough additional processes to cope with traffic.
#
#               idle=N
#
#       Sets a minimum of how many processes Squid is to try and keep available
#       at all times. When traffic begins to rise above what the existing
#       processes can handle this many more will be spawned up to the maximum
#       configured. A minimum setting of 1 is required.
#
#               concurrency=
#
#       The number of requests each certificate validator helper can handle in
#       parallel. A value of 0 indicates the certficate validator does not
#       support concurrency. Defaults to 1.
#
#       When this directive is set to a value >= 1 then the protocol
#       used to communicate with the helper is modified to include
#       a request ID in front of the request/response. The request
#       ID from the request must be echoed back with the response
#       to that request.
#
#               queue-size=N
#
#       Sets the maximum number of queued requests. A request is queued when
#       no existing child can accept it due to concurrency limit and no new
#       child can be started due to numberofchildren limit. If the queued
#       requests exceed queue size for more than 3 minutes squid aborts its
#       operation. The default value is set to 2*numberofchildren.
#
#       You must have at least one ssl_crt_validator process.
#Default:
# sslcrtvalidator_children 32 startup=5 idle=1 concurrency=1

# OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
# -----------------------------------------------------------------------------

#  TAG: cache_peer
#       To specify other caches in a hierarchy, use the format:
#
#               cache_peer hostname type http-port icp-port [options]
#
#       For example,
#
#       #                                        proxy  icp
#       #          hostname             type     port   port  options
#       #          -------------------- -------- ----- -----  -----------
#       cache_peer parent.foo.net       parent    3128  3130  default
#       cache_peer sib1.foo.net         sibling   3128  3130  proxy-only
#       cache_peer sib2.foo.net         sibling   3128  3130  proxy-only
#       cache_peer example.com          parent    80       0  default
#       cache_peer cdn.example.com      sibling   3128     0  
#
#             type:     either 'parent', 'sibling', or 'multicast'.
#
#       proxy-port:     The port number where the peer accept HTTP requests.
#                       For other Squid proxies this is usually 3128
#                       For web servers this is usually 80
#
#         icp-port:     Used for querying neighbor caches about objects.
#                       Set to 0 if the peer does not support ICP or HTCP.
#                       See ICP and HTCP options below for additional details.
#
#
#       ==== ICP OPTIONS ====
#
#       You MUST also set icp_port and icp_access explicitly when using these options.
#       The defaults will prevent peer traffic using ICP.
#
#
#       no-query        Disable ICP queries to this neighbor.
#
#       multicast-responder
#                       Indicates the named peer is a member of a multicast group.
#                       ICP queries will not be sent directly to the peer, but ICP
#                       replies will be accepted from it.
#
#       closest-only    Indicates that, for ICP_OP_MISS replies, we'll only forward
#                       CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
#
#       background-ping
#                       To only send ICP queries to this neighbor infrequently.
#                       This is used to keep the neighbor round trip time updated
#                       and is usually used in conjunction with weighted-round-robin.
#
#
#       ==== HTCP OPTIONS ====
#
#       You MUST also set htcp_port and htcp_access explicitly when using these options.
#       The defaults will prevent peer traffic using HTCP.
#
#
#       htcp            Send HTCP, instead of ICP, queries to the neighbor.
#                       You probably also want to set the "icp-port" to 4827
#                       instead of 3130. This directive accepts a comma separated
#                       list of options described below.
#
#       htcp=oldsquid   Send HTCP to old Squid versions (2.5 or earlier).
#
#       htcp=no-clr     Send HTCP to the neighbor but without
#                       sending any CLR requests.  This cannot be used with
#                       only-clr.
#
#       htcp=only-clr   Send HTCP to the neighbor but ONLY CLR requests.
#                       This cannot be used with no-clr.
#
#       htcp=no-purge-clr
#                       Send HTCP to the neighbor including CLRs but only when
#                       they do not result from PURGE requests.
#
#       htcp=forward-clr
#                       Forward any HTCP CLR requests this proxy receives to the peer.
#
#
#       ==== PEER SELECTION METHODS ====
#
#       The default peer selection method is ICP, with the first responding peer
#       being used as source. These options can be used for better load balancing.
#
#
#       default         This is a parent cache which can be used as a "last-resort"
#                       if a peer cannot be located by any of the peer-selection methods.
#                       If specified more than once, only the first is used.
#
#       round-robin     Load-Balance parents which should be used in a round-robin
#                       fashion in the absence of any ICP queries.
#                       weight=N can be used to add bias.
#
#       weighted-round-robin
#                       Load-Balance parents which should be used in a round-robin
#                       fashion with the frequency of each parent being based on the
#                       round trip time. Closer parents are used more often.
#                       Usually used for background-ping parents.
#                       weight=N can be used to add bias.
#
#       carp            Load-Balance parents which should be used as a CARP array.
#                       The requests will be distributed among the parents based on the
#                       CARP load balancing hash function based on their weight.
#
#       userhash        Load-balance parents based on the client proxy_auth or ident username.
#
#       sourcehash      Load-balance parents based on the client source IP.
#
#       multicast-siblings
#                       To be used only for cache peers of type "multicast".
#                       ALL members of this multicast group have "sibling"
#                       relationship with it, not "parent".  This is to a multicast
#                       group when the requested object would be fetched only from
#                       a "parent" cache, anyway.  It's useful, e.g., when
#                       configuring a pool of redundant Squid proxies, being
#                       members of the same multicast group.
#
#
#       ==== PEER SELECTION OPTIONS ====
#
#       weight=N        use to affect the selection of a peer during any weighted
#                       peer-selection mechanisms.
#                       The weight must be an integer; default is 1,
#                       larger weights are favored more.
#                       This option does not affect parent selection if a peering
#                       protocol is not in use.
#
#       basetime=N      Specify a base amount to be subtracted from round trip
#                       times of parents.
#                       It is subtracted before division by weight in calculating
#                       which parent to fectch from. If the rtt is less than the
#                       base time the rtt is set to a minimal value.
#
#       ttl=N           Specify a TTL to use when sending multicast ICP queries
#                       to this address.
#                       Only useful when sending to a multicast group.
#                       Because we don't accept ICP replies from random
#                       hosts, you must configure other group members as
#                       peers with the 'multicast-responder' option.
#
#       no-delay        To prevent access to this neighbor from influencing the
#                       delay pools.
#
#       digest-url=URL  Tell Squid to fetch the cache digest (if digests are
#                       enabled) for this host from the specified URL rather
#                       than the Squid default location.
#
#
#       ==== CARP OPTIONS ====
#
#       carp-key=key-specification
#                       use a different key than the full URL to hash against the peer.
#                       the key-specification is a comma-separated list of the keywords
#                       scheme, host, port, path, params
#                       Order is not important.
#
#       ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
#
#       originserver    Causes this parent to be contacted as an origin server.
#                       Meant to be used in accelerator setups when the peer
#                       is a web server.
#
#       forceddomain=name
#                       Set the Host header of requests forwarded to this peer.
#                       Useful in accelerator setups where the server (peer)
#                       expects a certain domain name but clients may request
#                       others. ie example.com or www.example.com
#
#       no-digest       Disable request of cache digests.
#
#       no-netdb-exchange
#                       Disables requesting ICMP RTT database (NetDB).
#
#
#       ==== AUTHENTICATION OPTIONS ====
#
#       login=user:password
#                       If this is a personal/workgroup proxy and your parent
#                       requires proxy authentication.
#
#                       Note: The string can include URL escapes (i.e. %20 for
#                       spaces). This also means % must be written as %%.
#
#       login=PASSTHRU
#                       Send login details received from client to this peer.
#                       Both Proxy- and WWW-Authorization headers are passed
#                       without alteration to the peer.
#                       Authentication is not required by Squid for this to work.
#
#                       Note: This will pass any form of authentication but
#                       only Basic auth will work through a proxy unless the
#                       connection-auth options are also used.
#
#       login=PASS      Send login details received from client to this peer.
#                       Authentication is not required by this option.
#
#                       If there are no client-provided authentication headers
#                       to pass on, but username and password are available
#                       from an external ACL user= and password= result tags
#                       they may be sent instead.
#
#                       Note: To combine this with proxy_auth both proxies must
#                       share the same user database as HTTP only allows for
#                       a single login (one for proxy, one for origin server).
#                       Also be warned this will expose your users proxy
#                       password to the peer. USE WITH CAUTION
#
#       login=*:password
#                       Send the username to the upstream cache, but with a
#                       fixed password. This is meant to be used when the peer
#                       is in another administrative domain, but it is still
#                       needed to identify each user.
#                       The star can optionally be followed by some extra
#                       information which is added to the username. This can
#                       be used to identify this proxy to the peer, similar to
#                       the login=username:password option above.
#
#       login=NEGOTIATE
#                       If this is a personal/workgroup proxy and your parent
#                       requires a secure proxy authentication.
#                       The first principal from the default keytab or defined by
#                       the environment variable KRB5_KTNAME will be used. 
#
#                       WARNING: The connection may transmit requests from multiple
#                       clients. Negotiate often assumes end-to-end authentication
#                       and a single-client. Which is not strictly true here.
#
#       login=NEGOTIATE:principal_name
#                       If this is a personal/workgroup proxy and your parent
#                       requires a secure proxy authentication. 
#                       The principal principal_name from the default keytab or
#                       defined by the environment variable KRB5_KTNAME will be
#                       used.
#
#                       WARNING: The connection may transmit requests from multiple
#                       clients. Negotiate often assumes end-to-end authentication
#                       and a single-client. Which is not strictly true here.
#
#       connection-auth=on|off
#                       Tell Squid that this peer does or not support Microsoft
#                       connection oriented authentication, and any such
#                       challenges received from there should be ignored.
#                       Default is auto to automatically determine the status
#                       of the peer.
#
#       auth-no-keytab
#                       Do not use a keytab to authenticate to a peer when
#                       login=NEGOTIATE is specified. Let the GSSAPI
#                       implementation determine which already existing
#                       credentials cache to use instead.
#
#
#       ==== SSL / HTTPS / TLS OPTIONS ====
#
#       tls             Encrypt connections to this peer with TLS.
#
#       sslcert=/path/to/ssl/certificate
#                       A client X.509 certificate to use when connecting to
#                       this peer.
#
#       sslkey=/path/to/ssl/key
#                       The private key corresponding to sslcert above.
#
#                       If sslkey= is not specified sslcert= is assumed to
#                       reference a PEM file containing both the certificate
#                       and private key.
#
#       Notes:
#
#       On Debian/Ubuntu systems a default snakeoil certificate is
#       available in /etc/ssl and users can set:
#
#               sslcert=/etc/ssl/certs/ssl-cert-snakeoil.pem
#
#       and
#
#               sslkey=/etc/ssl/private/ssl-cert-snakeoil.key
#
#       for testing.
#
#       sslcipher=...   The list of valid SSL ciphers to use when connecting
#                       to this peer.
#
#       tls-min-version=1.N
#                       The minimum TLS protocol version to permit. To control
#                       SSLv3 use the tls-options= parameter.
#                       Supported Values: 1.0 (default), 1.1, 1.2
#
#       tls-options=... Specify various TLS implementation options.
#
#                       OpenSSL options most important are:
#
#                           NO_SSLv3    Disallow the use of SSLv3
#
#                           SINGLE_DH_USE
#                                     Always create a new key when using
#                                     temporary/ephemeral DH key exchanges
#
#                           NO_TICKET
#                                     Disable use of RFC5077 session tickets.
#                                     Some servers may have problems
#                                     understanding the TLS extension due
#                                     to ambiguous specification in RFC4507.
#
#                           ALL       Enable various bug workarounds
#                                     suggested as "harmless" by OpenSSL
#                                     Be warned that this reduces SSL/TLS
#                                     strength to some attacks.
#
#                       See the OpenSSL SSL_CTX_set_options documentation for a
#                       more complete list.
#
#                       GnuTLS options most important are:
#
#                           %NO_TICKETS
#                                     Disable use of RFC5077 session tickets.
#                                     Some servers may have problems
#                                     understanding the TLS extension due
#                                     to ambiguous specification in RFC4507.
#
#                               See the GnuTLS Priority Strings documentation
#                               for a more complete list.
#                               http://www.gnutls.org/manual/gnutls.html#Priority-Strings
#
#       tls-cafile=     PEM file containing CA certificates to use when verifying
#                       the peer certificate. May be repeated to load multiple files.
#
#       sslcapath=...   A directory containing additional CA certificates to
#                       use when verifying the peer certificate.
#                       Requires OpenSSL or LibreSSL.
#
#       sslcrlfile=...  A certificate revocation list file to use when
#                       verifying the peer certificate.
#
#       sslflags=...    Specify various flags modifying the SSL implementation:
#
#                       DONT_VERIFY_PEER
#                               Accept certificates even if they fail to
#                               verify.
#
#                       DONT_VERIFY_DOMAIN
#                               Don't verify the peer certificate
#                               matches the server name
#
#       ssldomain=      The peer name as advertised in it's certificate.
#                       Used for verifying the correctness of the received peer
#                       certificate. If not specified the peer hostname will be
#                       used.
#
#       front-end-https[=off|on|auto]
#                       Enable the "Front-End-Https: On" header needed when
#                       using Squid as a SSL frontend in front of Microsoft OWA.
#                       See MS KB document Q307347 for details on this header.
#                       If set to auto the header will only be added if the
#                       request is forwarded as a https:// URL.
#
#       tls-default-ca[=off]
#                       Whether to use the system Trusted CAs. Default is ON.
#
#       tls-no-npn      Do not use the TLS NPN extension to advertise HTTP/1.1.
#
#       ==== GENERAL OPTIONS ====
#
#       connect-timeout=N
#                       A peer-specific connect timeout.
#                       Also see the peer_connect_timeout directive.
#
#       connect-fail-limit=N
#                       How many times connecting to a peer must fail before
#                       it is marked as down. Standby connection failures
#                       count towards this limit. Default is 10.
#
#       allow-miss      Disable Squid's use of only-if-cached when forwarding
#                       requests to siblings. This is primarily useful when
#                       icp_hit_stale is used by the sibling. Excessive use
#                       of this option may result in forwarding loops. One way
#                       to prevent peering loops when using this option, is to
#                       deny cache peer usage on requests from a peer:
#                       acl fromPeer ...
#                       cache_peer_access peerName deny fromPeer
#
#       max-conn=N      Limit the number of concurrent connections the Squid
#                       may open to this peer, including already opened idle
#                       and standby connections. There is no peer-specific
#                       connection limit by default.
#
#                       A peer exceeding the limit is not used for new
#                       requests unless a standby connection is available.
#
#                       max-conn currently works poorly with idle persistent
#                       connections: When a peer reaches its max-conn limit,
#                       and there are idle persistent connections to the peer,
#                       the peer may not be selected because the limiting code
#                       does not know whether Squid can reuse those idle
#                       connections.
#
#       standby=N       Maintain a pool of N "hot standby" connections to an
#                       UP peer, available for requests when no idle
#                       persistent connection is available (or safe) to use.
#                       By default and with zero N, no such pool is maintained.
#                       N must not exceed the max-conn limit (if any).
#
#                       At start or after reconfiguration, Squid opens new TCP
#                       standby connections until there are N connections
#                       available and then replenishes the standby pool as
#                       opened connections are used up for requests. A used
#                       connection never goes back to the standby pool, but
#                       may go to the regular idle persistent connection pool
#                       shared by all peers and origin servers.
#
#                       Squid never opens multiple new standby connections
#                       concurrently.  This one-at-a-time approach minimizes
#                       flooding-like effect on peers. Furthermore, just a few
#                       standby connections should be sufficient in most cases
#                       to supply most new requests with a ready-to-use
#                       connection.
#
#                       Standby connections obey server_idle_pconn_timeout.
#                       For the feature to work as intended, the peer must be
#                       configured to accept and keep them open longer than
#                       the idle timeout at the connecting Squid, to minimize
#                       race conditions typical to idle used persistent
#                       connections. Default request_timeout and
#                       server_idle_pconn_timeout values ensure such a
#                       configuration.
#
#       name=xxx        Unique name for the peer.
#                       Required if you have multiple peers on the same host
#                       but different ports.
#                       This name can be used in cache_peer_access and similar
#                       directives to identify the peer.
#                       Can be used by outgoing access controls through the
#                       peername ACL type.
#
#       no-tproxy       Do not use the client-spoof TPROXY support when forwarding
#                       requests to this peer. Use normal address selection instead.
#                       This overrides the spoof_client_ip ACL.
#
#       proxy-only      objects fetched from the peer will not be stored locally.
#
#Default:
# none

#  TAG: cache_peer_access
#       Restricts usage of cache_peer proxies.
#
#       Usage:
#               cache_peer_access peer-name allow|deny [!]aclname ...
#
#       For the required peer-name parameter, use either the value of the
#       cache_peer name=value parameter or, if name=value is missing, the
#       cache_peer hostname parameter.
#
#       This directive narrows down the selection of peering candidates, but
#       does not determine the order in which the selected candidates are
#       contacted. That order is determined by the peer selection algorithms
#       (see PEER SELECTION sections in the cache_peer documentation).
#
#       If a deny rule matches, the corresponding peer will not be contacted
#       for the current transaction -- Squid will not send ICP queries and
#       will not forward HTTP requests to that peer. An allow match leaves
#       the corresponding peer in the selection. The first match for a given
#       peer wins for that peer.
#
#       The relative order of cache_peer_access directives for the same peer
#       matters. The relative order of any two cache_peer_access directives
#       for different peers does not matter. To ease interpretation, it is a
#       good idea to group cache_peer_access directives for the same peer
#       together.
#
#       A single cache_peer_access directive may be evaluated multiple times
#       for a given transaction because individual peer selection algorithms
#       may check it independently from each other. These redundant checks
#       may be optimized away in future Squid versions.
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#
#Default:
# No peer usage restrictions.

#  TAG: neighbor_type_domain
#       Modify the cache_peer neighbor type when passing requests
#       about specific domains to the peer.
#
#       Usage:
#                neighbor_type_domain neighbor parent|sibling domain domain ...
#
#       For example:
#               cache_peer foo.example.com parent 3128 3130
#               neighbor_type_domain foo.example.com sibling .au .de
#
#       The above configuration treats all requests to foo.example.com as a
#       parent proxy unless the request is for a .au or .de ccTLD domain name.
#Default:
# The peer type from cache_peer directive is used for all requests to that peer.

#  TAG: dead_peer_timeout       (seconds)
#       This controls how long Squid waits to declare a peer cache
#       as "dead."  If there are no ICP replies received in this
#       amount of time, Squid will declare the peer dead and not
#       expect to receive any further ICP replies.  However, it
#       continues to send ICP queries, and will mark the peer as
#       alive upon receipt of the first subsequent ICP reply.
#
#       This timeout also affects when Squid expects to receive ICP
#       replies from peers.  If more than 'dead_peer' seconds have
#       passed since the last ICP reply was received, Squid will not
#       expect to receive an ICP reply on the next query.  Thus, if
#       your time between requests is greater than this timeout, you
#       will see a lot of requests sent DIRECT to origin servers
#       instead of to your parents.
#Default:
# dead_peer_timeout 10 seconds

#  TAG: forward_max_tries
#       Limits the number of attempts to forward the request.
#
#       For the purpose of this limit, Squid counts all high-level request
#       forwarding attempts, including any same-destination retries after
#       certain persistent connection failures and any attempts to use a
#       different peer. However, low-level connection reopening attempts
#       (enabled using connect_retries) are not counted.
#
#       See also: forward_timeout and connect_retries.
#Default:
# forward_max_tries 25

# MEMORY CACHE OPTIONS
# -----------------------------------------------------------------------------

#  TAG: cache_mem       (bytes)
#       NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
#       IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
#       USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
#       THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
#
#       'cache_mem' specifies the ideal amount of memory to be used
#       for:
#               * In-Transit objects
#               * Hot Objects
#               * Negative-Cached objects
#
#       Data for these objects are stored in 4 KB blocks.  This
#       parameter specifies the ideal upper limit on the total size of
#       4 KB blocks allocated.  In-Transit objects take the highest
#       priority.
#
#       In-transit objects have priority over the others.  When
#       additional space is needed for incoming data, negative-cached
#       and hot objects will be released.  In other words, the
#       negative-cached and hot objects will fill up any unused space
#       not needed for in-transit objects.
#
#       If circumstances require, this limit will be exceeded.
#       Specifically, if your incoming request rate requires more than
#       'cache_mem' of memory to hold in-transit objects, Squid will
#       exceed this limit to satisfy the new requests.  When the load
#       decreases, blocks will be freed until the high-water mark is
#       reached.  Thereafter, blocks will be used to store hot
#       objects.
#
#       If shared memory caching is enabled, Squid does not use the shared
#       cache space for in-transit objects, but they still consume as much
#       local memory as they need. For more details about the shared memory
#       cache, see memory_cache_shared.
#Default:
# cache_mem 256 MB

#  TAG: maximum_object_size_in_memory   (bytes)
#       Objects greater than this size will not be attempted to kept in
#       the memory cache. This should be set high enough to keep objects
#       accessed frequently in memory to improve performance whilst low
#       enough to keep larger objects from hoarding cache_mem.
#Default:
# maximum_object_size_in_memory 512 KB

#  TAG: memory_cache_shared     on|off
#       Controls whether the memory cache is shared among SMP workers.
#
#       The shared memory cache is meant to occupy cache_mem bytes and replace
#       the non-shared memory cache, although some entities may still be
#       cached locally by workers for now (e.g., internal and in-transit
#       objects may be served from a local memory cache even if shared memory
#       caching is enabled).
#
#       By default, the memory cache is shared if and only if all of the
#       following conditions are satisfied: Squid runs in SMP mode with
#       multiple workers, cache_mem is positive, and Squid environment
#       supports required IPC primitives (e.g., POSIX shared memory segments
#       and GCC-style atomic operations).
#
#       To avoid blocking locks, shared memory uses opportunistic algorithms
#       that do not guarantee that every cachable entity that could have been
#       shared among SMP workers will actually be shared.
#Default:
# "on" where supported if doing memory caching with multiple SMP workers.

#  TAG: memory_cache_mode
#       Controls which objects to keep in the memory cache (cache_mem)
#
#       always  Keep most recently fetched objects in memory (default)
#
#       disk    Only disk cache hits are kept in memory, which means
#               an object must first be cached on disk and then hit
#               a second time before cached in memory.
#
#       network Only objects fetched from network is kept in memory
#Default:
# Keep the most recently fetched objects in memory

#  TAG: memory_replacement_policy
#       The memory replacement policy parameter determines which
#       objects are purged from memory when memory space is needed.
#
#       See cache_replacement_policy for details on algorithms.
#Default:
# memory_replacement_policy lru

# DISK CACHE OPTIONS
# -----------------------------------------------------------------------------

#  TAG: cache_replacement_policy
#       The cache replacement policy parameter determines which
#       objects are evicted (replaced) when disk space is needed.
#
#           lru       : Squid's original list based LRU policy
#           heap GDSF : Greedy-Dual Size Frequency
#           heap LFUDA: Least Frequently Used with Dynamic Aging
#           heap LRU  : LRU policy implemented using a heap
#
#       Applies to any cache_dir lines listed below this directive.
#
#       The LRU policies keeps recently referenced objects.
#
#       The heap GDSF policy optimizes object hit rate by keeping smaller
#       popular objects in cache so it has a better chance of getting a
#       hit.  It achieves a lower byte hit rate than LFUDA though since
#       it evicts larger (possibly popular) objects.
#
#       The heap LFUDA policy keeps popular objects in cache regardless of
#       their size and thus optimizes byte hit rate at the expense of
#       hit rate since one large, popular object will prevent many
#       smaller, slightly less popular objects from being cached.
#
#       Both policies utilize a dynamic aging mechanism that prevents
#       cache pollution that can otherwise occur with frequency-based
#       replacement policies.
#
#       NOTE: if using the LFUDA replacement policy you should increase
#       the value of maximum_object_size above its default of 4 MB to
#       to maximize the potential byte hit rate improvement of LFUDA.
#
#       For more information about the GDSF and LFUDA cache replacement
#       policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
#       and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
#Default:
# cache_replacement_policy lru

#  TAG: minimum_object_size     (bytes)
#       Objects smaller than this size will NOT be saved on disk.  The
#       value is specified in bytes, and the default is 0 KB, which
#       means all responses can be stored.
#Default:
# no limit

#  TAG: maximum_object_size     (bytes)
#       Set the default value for max-size parameter on any cache_dir.
#       The value is specified in bytes, and the default is 4 MB.
#
#       If you wish to get a high BYTES hit ratio, you should probably
#       increase this (one 32 MB object hit counts for 3200 10KB
#       hits).
#
#       If you wish to increase hit ratio more than you want to
#       save bandwidth you should leave this low.
#
#       NOTE: if using the LFUDA replacement policy you should increase
#       this value to maximize the byte hit rate improvement of LFUDA!
#       See cache_replacement_policy for a discussion of this policy.
#Default:
# maximum_object_size 4 MB

#  TAG: cache_dir
#       Format:
#               cache_dir Type Directory-Name Fs-specific-data [options]
#
#       You can specify multiple cache_dir lines to spread the
#       cache among different disk partitions.
#
#       Type specifies the kind of storage system to use. Only "ufs"
#       is built by default. To enable any of the other storage systems
#       see the --enable-storeio configure option.
#
#       'Directory' is a top-level directory where cache swap
#       files will be stored.  If you want to use an entire disk
#       for caching, this can be the mount-point directory.
#       The directory must exist and be writable by the Squid
#       process.  Squid will NOT create this directory for you.
#
#       In SMP configurations, cache_dir must not precede the workers option
#       and should use configuration macros or conditionals to give each
#       worker interested in disk caching a dedicated cache directory.
#
#
#       ====  The ufs store type  ====
#
#       "ufs" is the old well-known Squid storage format that has always
#       been there.
#
#       Usage:
#               cache_dir ufs Directory-Name Mbytes L1 L2 [options]
#
#       'Mbytes' is the amount of disk space (MB) to use under this
#       directory.  The default is 100 MB.  Change this to suit your
#       configuration.  Do NOT put the size of your disk drive here.
#       Instead, if you want Squid to use the entire disk drive,
#       subtract 20% and use that value.
#
#       'L1' is the number of first-level subdirectories which
#       will be created under the 'Directory'.  The default is 16.
#
#       'L2' is the number of second-level subdirectories which
#       will be created under each first-level directory.  The default
#       is 256.
#
#
#       ====  The aufs store type  ====
#
#       "aufs" uses the same storage format as "ufs", utilizing
#       POSIX-threads to avoid blocking the main Squid process on
#       disk-I/O. This was formerly known in Squid as async-io.
#
#       Usage:
#               cache_dir aufs Directory-Name Mbytes L1 L2 [options]
#
#       see argument descriptions under ufs above
#
#
#       ====  The diskd store type  ====
#
#       "diskd" uses the same storage format as "ufs", utilizing a
#       separate process to avoid blocking the main Squid process on
#       disk-I/O.
#
#       Usage:
#               cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
#
#       see argument descriptions under ufs above
#
#       Q1 specifies the number of unacknowledged I/O requests when Squid
#       stops opening new files. If this many messages are in the queues,
#       Squid won't open new files. Default is 64
#
#       Q2 specifies the number of unacknowledged messages when Squid
#       starts blocking.  If this many messages are in the queues,
#       Squid blocks until it receives some replies. Default is 72
#
#       When Q1 < Q2 (the default), the cache directory is optimized
#       for lower response time at the expense of a decrease in hit
#       ratio.  If Q1 > Q2, the cache directory is optimized for
#       higher hit ratio at the expense of an increase in response
#       time.
#
#
#       ====  The rock store type  ====
#
#       Usage:
#           cache_dir rock Directory-Name Mbytes [options]
#
#       The Rock Store type is a database-style storage. All cached
#       entries are stored in a "database" file, using fixed-size slots.
#       A single entry occupies one or more slots.
#
#       If possible, Squid using Rock Store creates a dedicated kid
#       process called "disker" to avoid blocking Squid worker(s) on disk
#       I/O. One disker kid is created for each rock cache_dir.  Diskers
#       are created only when Squid, running in daemon mode, has support
#       for the IpcIo disk I/O module.
#
#       swap-timeout=msec: Squid will not start writing a miss to or
#       reading a hit from disk if it estimates that the swap operation
#       will take more than the specified number of milliseconds. By
#       default and when set to zero, disables the disk I/O time limit
#       enforcement. Ignored when using blocking I/O module because
#       blocking synchronous I/O does not allow Squid to estimate the
#       expected swap wait time.
#
#       max-swap-rate=swaps/sec: Artificially limits disk access using
#       the specified I/O rate limit. Swap out requests that
#       would cause the average I/O rate to exceed the limit are
#       delayed. Individual swap in requests (i.e., hits or reads) are
#       not delayed, but they do contribute to measured swap rate and
#       since they are placed in the same FIFO queue as swap out
#       requests, they may wait longer if max-swap-rate is smaller.
#       This is necessary on file systems that buffer "too
#       many" writes and then start blocking Squid and other processes
#       while committing those writes to disk.  Usually used together
#       with swap-timeout to avoid excessive delays and queue overflows
#       when disk demand exceeds available disk "bandwidth". By default
#       and when set to zero, disables the disk I/O rate limit
#       enforcement. Currently supported by IpcIo module only.
#
#       slot-size=bytes: The size of a database "record" used for
#       storing cached responses. A cached response occupies at least
#       one slot and all database I/O is done using individual slots so
#       increasing this parameter leads to more disk space waste while
#       decreasing it leads to more disk I/O overheads. Should be a
#       multiple of your operating system I/O page size. Defaults to
#       16KBytes. A housekeeping header is stored with each slot and
#       smaller slot-sizes will be rejected. The header is smaller than
#       100 bytes.
#
#
#       ==== COMMON OPTIONS ====
#
#       no-store        no new objects should be stored to this cache_dir.
#
#       min-size=n      the minimum object size in bytes this cache_dir
#                       will accept.  It's used to restrict a cache_dir
#                       to only store large objects (e.g. AUFS) while
#                       other stores are optimized for smaller objects
#                       (e.g. Rock).
#                       Defaults to 0.
#
#       max-size=n      the maximum object size in bytes this cache_dir
#                       supports.
#                       The value in maximum_object_size directive sets
#                       the default unless more specific details are
#                       available (ie a small store capacity).
#
#       Note: To make optimal use of the max-size limits you should order
#       the cache_dir lines with the smallest max-size value first.
#
#Default:
# No disk cache. Store cache ojects only in memory.
#

# Uncomment and adjust the following to add a disk cache directory.
#cache_dir ufs /var/spool/squid 100 16 256

#  TAG: store_dir_select_algorithm
#       How Squid selects which cache_dir to use when the response
#       object will fit into more than one.
#
#       Regardless of which algorithm is used the cache_dir min-size
#       and max-size parameters are obeyed. As such they can affect
#       the selection algorithm by limiting the set of considered
#       cache_dir.
#
#       Algorithms:
#
#               least-load
#
#       This algorithm is suited to caches with similar cache_dir
#       sizes and disk speeds.
#
#       The disk with the least I/O pending is selected.
#       When there are multiple disks with the same I/O load ranking
#       the cache_dir with most available capacity is selected.
#
#       When a mix of cache_dir sizes are configured the faster disks
#       have a naturally lower I/O loading and larger disks have more
#       capacity. So space used to store objects and data throughput
#       may be very unbalanced towards larger disks.
#
#
#               round-robin
#
#       This algorithm is suited to caches with unequal cache_dir
#       disk sizes.
#
#       Each cache_dir is selected in a rotation. The next suitable
#       cache_dir is used.
#
#       Available cache_dir capacity is only considered in relation
#       to whether the object will fit and meets the min-size and
#       max-size parameters.
#
#       Disk I/O loading is only considered to prevent overload on slow
#       disks. This algorithm does not spread objects by size, so any
#       I/O loading per-disk may appear very unbalanced and volatile.
#
#       If several cache_dirs use similar min-size, max-size, or other
#       limits to to reject certain responses, then do not group such
#       cache_dir lines together, to avoid round-robin selection bias
#       towards the first cache_dir after the group. Instead, interleave
#       cache_dir lines from different groups. For example:
#
#               store_dir_select_algorithm round-robin
#               cache_dir rock /hdd1 ... min-size=100000
#               cache_dir rock /ssd1 ... max-size=99999
#               cache_dir rock /hdd2 ... min-size=100000
#               cache_dir rock /ssd2 ... max-size=99999
#               cache_dir rock /hdd3 ... min-size=100000
#               cache_dir rock /ssd3 ... max-size=99999
#Default:
# store_dir_select_algorithm least-load

#  TAG: max_open_disk_fds
#       To avoid having disk as the I/O bottleneck Squid can optionally
#       bypass the on-disk cache if more than this amount of disk file
#       descriptors are open.
#
#       A value of 0 indicates no limit.
#Default:
# no limit

#  TAG: cache_swap_low  (percent, 0-100)
#       The low-water mark for AUFS/UFS/diskd cache object eviction by
#       the cache_replacement_policy algorithm.
#
#       Removal begins when the swap (disk) usage of a cache_dir is
#       above this low-water mark and attempts to maintain utilization
#       near the low-water mark.
#
#       As swap utilization increases towards the high-water mark set
#       by cache_swap_high object eviction becomes more agressive.
#
#       The value difference in percentages between low- and high-water
#       marks represent an eviction rate of 300 objects per second and
#       the rate continues to scale in agressiveness by multiples of
#       this above the high-water mark.
#
#       Defaults are 90% and 95%. If you have a large cache, 5% could be
#       hundreds of MB. If this is the case you may wish to set these
#       numbers closer together.
#
#       See also cache_swap_high and cache_replacement_policy
#Default:
# cache_swap_low 90

#  TAG: cache_swap_high (percent, 0-100)
#       The high-water mark for AUFS/UFS/diskd cache object eviction by
#       the cache_replacement_policy algorithm.
#
#       Removal begins when the swap (disk) usage of a cache_dir is
#       above the low-water mark set by cache_swap_low and attempts to
#       maintain utilization near the low-water mark.
#
#       As swap utilization increases towards this high-water mark object
#       eviction becomes more agressive.
#
#       The value difference in percentages between low- and high-water
#       marks represent an eviction rate of 300 objects per second and
#       the rate continues to scale in agressiveness by multiples of
#       this above the high-water mark.
#
#       Defaults are 90% and 95%. If you have a large cache, 5% could be
#       hundreds of MB. If this is the case you may wish to set these
#       numbers closer together.
#
#       See also cache_swap_low and cache_replacement_policy
#Default:
# cache_swap_high 95

# LOGFILE OPTIONS
# -----------------------------------------------------------------------------

#  TAG: logformat
#       Usage:
#
#       logformat <name> <format specification>
#
#       Defines an access log format.
#
#       The <format specification> is a string with embedded % format codes
#
#       % format codes all follow the same basic structure where all
#       components but the formatcode are optional and usually unnecessary,
#       especially when dealing with common codes.
#
#               % [encoding] [-] [[0]width] [{arg}] formatcode [{arg}]
#
#               encoding escapes or otherwise protects "special" characters:
#
#                       "       Quoted string encoding where quote(") and
#                               backslash(\) characters are \-escaped while
#                               CR, LF, and TAB characters are encoded as \r,
#                               \n, and \t two-character sequences.
#
#                       [       Custom Squid encoding where percent(%), square
#                               brackets([]), backslash(\) and characters with
#                               codes outside of [32,126] range are %-encoded.
#                               SP is not encoded. Used by log_mime_hdrs.
#
#                       #       URL encoding (a.k.a. percent-encoding) where
#                               all URL unsafe and control characters (per RFC
#                               1738) are %-encoded.
#
#                       /       Shell-like encoding where quote(") and
#                               backslash(\) characters are \-escaped while CR
#                               and LF characters are encoded as \r and \n
#                               two-character sequences. Values containing SP
#                               character(s) are surrounded by quotes(").
#
#                       '       Raw/as-is encoding with no escaping/quoting.
#
#                       Default encoding: When no explicit encoding is
#                       specified, each %code determines its own encoding.
#                       Most %codes use raw/as-is encoding, but some codes use
#                       a so called "pass-through URL encoding" where all URL
#                       unsafe and control characters (per RFC 1738) are
#                       %-encoded, but the percent character(%) is left as is.
#
#               -       left aligned
#
#               width   minimum and/or maximum field width:
#                           [width_min][.width_max]
#                       When minimum starts with 0, the field is zero-padded.
#                       String values exceeding maximum width are truncated.
#
#               {arg}   argument such as header name etc. This field may be
#                       placed before or after the token, but not both at once.
#
#       Format codes:
#
#               %       a literal % character
#               sn      Unique sequence number per log line entry
#               err_code    The ID of an error response served by Squid or
#                               a similar internal error identifier.
#               err_detail  Additional err_code-dependent error information.
#               note    The annotation specified by the argument. Also
#                       logs the adaptation meta headers set by the
#                       adaptation_meta configuration parameter.
#                       If no argument given all annotations logged.
#                       The argument may include a separator to use with
#                       annotation values:
#                            name[:separator]
#                       By default, multiple note values are separated with ","
#                       and multiple notes are separated with "\r\n".
#                       When logging named notes with %{name}note, the
#                       explicitly configured separator is used between note
#                       values. When logging all notes with %note, the
#                       explicitly configured separator is used between
#                       individual notes. There is currently no way to
#                       specify both value and notes separators when logging
#                       all notes with %note.
#               master_xaction  The master transaction identifier is an unsigned
#                       integer. These IDs are guaranteed to monotonically
#                       increase within a single worker process lifetime, with
#                       higher values corresponding to transactions that were
#                       accepted or initiated later. Due to current implementation
#                       deficiencies, some IDs are skipped (i.e. never logged).
#                       Concurrent workers and restarted workers use similar,
#                       overlapping sequences of master transaction IDs.
#
#       Connection related format codes:
#
#               >a      Client source IP address
#               >A      Client FQDN
#               >p      Client source port
#               >eui    Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
#               >la     Local IP address the client connected to
#               >lp     Local port number the client connected to
#               >qos    Client connection TOS/DSCP value set by Squid
#               >nfmark Client connection netfilter packet MARK set by Squid
#
#               la      Local listening IP address the client connection was connected to.
#               lp      Local listening port number the client connection was connected to.
#
#               <a      Server IP address of the last server or peer connection
#               <A      Server FQDN or peer name
#               <p      Server port number of the last server or peer connection
#               <la     Local IP address of the last server or peer connection
#               <lp     Local port number of the last server or peer connection
#               <qos    Server connection TOS/DSCP value set by Squid
#               <nfmark Server connection netfilter packet MARK set by Squid
#
#               >handshake Raw client handshake
#                       Initial client bytes received by Squid on a newly
#                       accepted TCP connection or inside a just established
#                       CONNECT tunnel. Squid stops accumulating handshake
#                       bytes as soon as the handshake parser succeeds or
#                       fails (determining whether the client is using the
#                       expected protocol).
#
#                       For HTTP clients, the handshake is the request line.
#                       For TLS clients, the handshake consists of all TLS
#                       records up to and including the TLS record that
#                       contains the last byte of the first ClientHello
#                       message. For clients using an unsupported protocol,
#                       this field contains the bytes received by Squid at the
#                       time of the handshake parsing failure.
#
#                       See the on_unsupported_protocol directive for more
#                       information on Squid handshake traffic expectations.
#
#                       Current support is limited to these contexts:
#                       - http_port connections, but only when the
#                         on_unsupported_protocol directive is in use.
#                       - https_port connections (and CONNECT tunnels) that
#                         are subject to the ssl_bump peek or stare action.
#
#                       To protect binary handshake data, this field is always
#                       base64-encoded (RFC 4648 Section 4). If logformat
#                       field encoding is configured, that encoding is applied
#                       on top of base64. Otherwise, the computed base64 value
#                       is recorded as is.
#
#       Time related format codes:
#
#               ts      Seconds since epoch
#               tu      subsecond time (milliseconds)
#               tl      Local time. Optional strftime format argument
#                               default %d/%b/%Y:%H:%M:%S %z
#               tg      GMT time. Optional strftime format argument
#                               default %d/%b/%Y:%H:%M:%S %z
#               tr      Response time (milliseconds)
#               dt      Total time spent making DNS lookups (milliseconds)
#               tS      Approximate master transaction start time in 
#                       <full seconds since epoch>.<fractional seconds> format.
#                       Currently, Squid considers the master transaction
#                       started when a complete HTTP request header initiating
#                       the transaction is received from the client. This is
#                       the same value that Squid uses to calculate transaction
#                       response time when logging %tr to access.log. Currently,
#                       Squid uses millisecond resolution for %tS values,
#                       similar to the default access.log "current time" field
#                       (%ts.%03tu).
#
#       Access Control related format codes:
#
#               et      Tag returned by external acl
#               ea      Log string returned by external acl
#               un      User name (any available)
#               ul      User name from authentication
#               ue      User name from external acl helper
#               ui      User name from ident
#               un      A user name. Expands to the first available name
#                       from the following list of information sources:
#                       - authenticated user name, like %ul
#                       - user name supplied by an external ACL, like %ue
#                       - SSL client name, like %us
#                       - ident user name, like %ui
#               credentials Client credentials. The exact meaning depends on
#                       the authentication scheme: For Basic authentication,
#                       it is the password; for Digest, the realm sent by the
#                       client; for NTLM and Negotiate, the client challenge
#                       or client credentials prefixed with "YR " or "KK ".
#
#       HTTP related format codes:
#
#           REQUEST
#
#               [http::]rm      Request method (GET/POST etc)
#               [http::]>rm     Request method from client
#               [http::]<rm     Request method sent to server or peer
#
#               [http::]ru      Request URL received (or computed) and sanitized
#
#                               Logs request URI received from the client, a
#                               request adaptation service, or a request
#                               redirector (whichever was applied last).
#
#                               Computed URLs are URIs of internally generated
#                               requests and various "error:..." URIs.
#
#                               Honors strip_query_terms and uri_whitespace.
#
#                               This field is not encoded by default. Encoding
#                               this field using variants of %-encoding will
#                               clash with uri_whitespace modifications that
#                               also use %-encoding.
#
#               [http::]>ru     Request URL received from the client (or computed)
#
#                               Computed URLs are URIs of internally generated
#                               requests and various "error:..." URIs.
#
#                               Unlike %ru, this request URI is not affected
#                               by request adaptation, URL rewriting services,
#                               and strip_query_terms.
#
#                               Honors uri_whitespace.
#
#                               This field is using pass-through URL encoding
#                               by default. Encoding this field using other
#                               variants of %-encoding will clash with
#                               uri_whitespace modifications that also use
#                               %-encoding.
#
#               [http::]<ru     Request URL sent to server or peer
#               [http::]>rs     Request URL scheme from client
#               [http::]<rs     Request URL scheme sent to server or peer
#               [http::]>rd     Request URL domain from client
#               [http::]<rd     Request URL domain sent to server or peer
#               [http::]>rP     Request URL port from client
#               [http::]<rP     Request URL port sent to server or peer
#               [http::]rp      Request URL path excluding hostname
#               [http::]>rp     Request URL path excluding hostname from client
#               [http::]<rp     Request URL path excluding hostname sent to server or peer
#               [http::]rv      Request protocol version
#               [http::]>rv     Request protocol version from client
#               [http::]<rv     Request protocol version sent to server or peer
#
#               [http::]>h      Original received request header.
#                               Usually differs from the request header sent by
#                               Squid, although most fields are often preserved.
#                               Accepts optional header field name/value filter
#                               argument using name[:[separator]element] format.
#               [http::]>ha     Received request header after adaptation and
#                               redirection (pre-cache REQMOD vectoring point).
#                               Usually differs from the request header sent by
#                               Squid, although most fields are often preserved.
#                               Optional header name argument as for >h
#
#           RESPONSE
#
#               [http::]<Hs     HTTP status code received from the next hop
#               [http::]>Hs     HTTP status code sent to the client
#
#               [http::]<h      Reply header. Optional header name argument
#                               as for >h
#
#               [http::]mt      MIME content type
#
#
#           SIZE COUNTERS
#
#               [http::]st      Total size of request + reply traffic with client
#               [http::]>st     Total size of request received from client.
#                               Excluding chunked encoding bytes.
#               [http::]<st     Total size of reply sent to client (after adaptation)
#
#               [http::]>sh     Size of request headers received from client
#               [http::]<sh     Size of reply headers sent to client (after adaptation)
#
#               [http::]<sH     Reply high offset sent
#               [http::]<sS     Upstream object size
#
#               [http::]<bs     Number of HTTP-equivalent message body bytes 
#                               received from the next hop, excluding chunked
#                               transfer encoding and control messages.
#                               Generated FTP/Gopher listings are treated as
#                               received bodies.
#
#           TIMING
#
#               [http::]<pt     Peer response time in milliseconds. The timer starts
#                               when the last request byte is sent to the next hop
#                               and stops when the last response byte is received.
#               [http::]<tt     Total time in milliseconds. The timer 
#                               starts with the first connect request (or write I/O)
#                               sent to the first selected peer. The timer stops
#                               with the last I/O with the last peer.
#
#       Squid handling related format codes:
#
#               Ss      Squid request status (TCP_MISS etc)
#               Sh      Squid hierarchy status (DEFAULT_PARENT etc)
#
#       SSL-related format codes:
#
#               ssl::bump_mode  SslBump decision for the transaction:
#
#                               For CONNECT requests that initiated bumping of
#                               a connection and for any request received on
#                               an already bumped connection, Squid logs the
#                               corresponding SslBump mode ("splice", "bump",
#                               "peek", "stare", "terminate", "server-first"
#                               or "client-first"). See the ssl_bump option 
#                               for more information about these modes.
#
#                               A "none" token is logged for requests that
#                               triggered "ssl_bump" ACL evaluation matching
#                               a "none" rule.
#
#                               In all other cases, a single dash ("-") is
#                               logged.
#
#               ssl::>sni       SSL client SNI sent to Squid.
#
#               ssl::>cert_subject
#                               The Subject field of the received client
#                               SSL certificate or a dash ('-') if Squid has
#                               received an invalid/malformed certificate or
#                               no certificate at all. Consider encoding the
#                               logged value because Subject often has spaces.
#
#               ssl::>cert_issuer
#                               The Issuer field of the received client
#                               SSL certificate or a dash ('-') if Squid has
#                               received an invalid/malformed certificate or
#                               no certificate at all. Consider encoding the
#                               logged value because Issuer often has spaces.
#
#               ssl::<cert_subject
#                               The Subject field of the received server
#                               TLS certificate or a dash ('-') if this is
#                               not available. Consider encoding the logged
#                               value because Subject often has spaces.
#
#               ssl::<cert_issuer
#                               The Issuer field of the received server
#                               TLS certificate or a dash ('-') if this is
#                               not available. Consider encoding the logged
#                               value because Issuer often has spaces.
#
#               ssl::<cert
#                               The received server x509 certificate in PEM
#                               format, including BEGIN and END lines (or a
#                               dash ('-') if the certificate is unavailable).
#
#                               WARNING: Large certificates will exceed the
#                               current 8KB access.log record limit, resulting
#                               in truncated records. Such truncation usually
#                               happens in the middle of a record field. The
#                               limit applies to all access logging modules.
#
#                               The logged certificate may have failed
#                               validation and may not be trusted by Squid.
#                               This field does not include any intermediate
#                               certificates that may have been received from
#                               the server or fetched during certificate
#                               validation process.
#
#                               Currently, Squid only collects server
#                               certificates during step3 of SslBump
#                               processing; connections that were not subject
#                               to ssl_bump rules or that did not match a peek
#                               or stare rule at step2 will not have the
#                               server certificate information.
#
#                               This field is using pass-through URL encoding
#                               by default.
#
#               ssl::<cert_errors
#                               The list of certificate validation errors
#                               detected by Squid (including OpenSSL and
#                               certificate validation helper components). The
#                               errors are listed in the discovery order. By
#                               default, the error codes are separated by ':'.
#                               Accepts an optional separator argument.
#
#               %ssl::>negotiated_version The negotiated TLS version of the
#                               client connection.
#
#               %ssl::<negotiated_version The negotiated TLS version of the
#                               last server or peer connection.
#
#               %ssl::>received_hello_version The TLS version of the Hello
#                               message received from TLS client.
#
#               %ssl::<received_hello_version The TLS version of the Hello
#                               message received from TLS server.
#
#               %ssl::>received_supported_version The maximum TLS version
#                               supported by the TLS client.
#
#               %ssl::<received_supported_version The maximum TLS version
#                               supported by the TLS server.
#
#               %ssl::>negotiated_cipher The negotiated cipher of the
#                               client connection.
#
#               %ssl::<negotiated_cipher The negotiated cipher of the
#                               last server or peer connection.
#
#       If ICAP is enabled, the following code becomes available (as
#       well as ICAP log codes documented with the icap_log option):
#
#               icap::tt        Total ICAP processing time for the HTTP
#                               transaction. The timer ticks when ICAP
#                               ACLs are checked and when ICAP
#                               transaction is in progress.
#
#       If adaptation is enabled the following codes become available:
#
#               adapt::<last_h  The header of the last ICAP response or
#                               meta-information from the last eCAP
#                               transaction related to the HTTP transaction.
#                               Like <h, accepts an optional header name
#                               argument.
#
#               adapt::sum_trs Summed adaptation transaction response
#                               times recorded as a comma-separated list in
#                               the order of transaction start time. Each time
#                               value is recorded as an integer number,
#                               representing response time of one or more
#                               adaptation (ICAP or eCAP) transaction in
#                               milliseconds.  When a failed transaction is
#                               being retried or repeated, its time is not
#                               logged individually but added to the
#                               replacement (next) transaction. See also:
#                               adapt::all_trs.
#
#               adapt::all_trs All adaptation transaction response times.
#                               Same as adaptation_strs but response times of
#                               individual transactions are never added
#                               together. Instead, all transaction response
#                               times are recorded individually.
#
#       You can prefix adapt::*_trs format codes with adaptation
#       service name in curly braces to record response time(s) specific
#       to that service. For example: %{my_service}adapt::sum_trs
#
#       Format codes related to the PROXY protocol:
#
#               proxy_protocol::>h PROXY protocol header, including optional TLVs.
#
#                               Supports the same field and element reporting/extraction logic
#                               as %http::>h. For configuration and reporting purposes, Squid
#                               maps each PROXY TLV to an HTTP header field: the TLV type
#                               (configured as a decimal integer) is the field name, and the
#                               TLV value is the field value. All TLVs of "LOCAL" connections
#                               (in PROXY protocol terminology) are currently skipped/ignored.
#
#                               Squid also maps the following standard PROXY protocol header
#                               blocks to pseudo HTTP headers (their names use PROXY
#                               terminology and start with a colon, following HTTP tradition
#                               for pseudo headers): :command, :version, :src_addr, :dst_addr,
#                               :src_port, and :dst_port.
#
#                               Without optional parameters, this logformat code logs
#                               pseudo headers and TLVs.
#
#                               This format code uses pass-through URL encoding by default.
#
#                               Example:
#                                       # relay custom PROXY TLV #224 to adaptation services
#                                       adaptation_meta Client-Foo "%proxy_protocol::>h{224}"
#
#                               See also: %http::>h
#
#       The default formats available (which do not need re-defining) are:
#
#logformat squid      %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
#logformat common     %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
#logformat combined   %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
#logformat referrer   %ts.%03tu %>a %{Referer}>h %ru
#logformat useragent  %>a [%tl] "%{User-Agent}>h"
#
#       NOTE: When the log_mime_hdrs directive is set to ON.
#               The squid, common and combined formats have a safely encoded copy
#               of the mime headers appended to each line within a pair of brackets.
#
#       NOTE: The common and combined formats are not quite true to the Apache definition.
#               The logs from Squid contain an extra status and hierarchy code appended.
#
#Default:
# The format definitions squid, common, combined, referrer, useragent are built in.

#  TAG: access_log
#       Configures whether and how Squid logs HTTP and ICP transactions.
#       If access logging is enabled, a single line is logged for every 
#       matching HTTP or ICP request. The recommended directive formats are:
#
#       access_log <module>:<place> [option ...] [acl acl ...]
#       access_log none [acl acl ...]
#
#       The following directive format is accepted but may be deprecated:
#       access_log <module>:<place> [<logformat name> [acl acl ...]]
#
#        In most cases, the first ACL name must not contain the '=' character
#       and should not be equal to an existing logformat name. You can always
#       start with an 'all' ACL to work around those restrictions.
#
#       Will log to the specified module:place using the specified format (which
#       must be defined in a logformat directive) those entries which match
#       ALL the acl's specified (which must be defined in acl clauses).
#       If no acl is specified, all requests will be logged to this destination.
#
#       ===== Available options for the recommended directive format =====
#
#       logformat=name          Names log line format (either built-in or
#                               defined by a logformat directive). Defaults
#                               to 'squid'.
#
#       buffer-size=64KB        Defines approximate buffering limit for log
#                               records (see buffered_logs).  Squid should not
#                               keep more than the specified size and, hence,
#                               should flush records before the buffer becomes
#                               full to avoid overflows under normal
#                               conditions (the exact flushing algorithm is
#                               module-dependent though).  The on-error option
#                               controls overflow handling.
#
#       on-error=die|drop       Defines action on unrecoverable errors. The
#                               'drop' action ignores (i.e., does not log)
#                               affected log records. The default 'die' action
#                               kills the affected worker. The drop action 
#                               support has not been tested for modules other
#                               than tcp.
#
#       rotate=N                Specifies the number of log file rotations to
#                               make when you run 'squid -k rotate'. The default
#                               is to obey the logfile_rotate directive. Setting
#                               rotate=0 will disable the file name rotation,
#                               but the log files are still closed and re-opened.
#                               This will enable you to rename the logfiles
#                               yourself just before sending the rotate signal.
#                               Only supported by the stdio module.
#
#       ===== Modules Currently available =====
#
#       none    Do not log any requests matching these ACL.
#               Do not specify Place or logformat name.
#
#       stdio   Write each log line to disk immediately at the completion of
#               each request.
#               Place: the filename and path to be written.
#
#       daemon  Very similar to stdio. But instead of writing to disk the log
#               line is passed to a daemon helper for asychronous handling instead.
#               Place: varies depending on the daemon.
#
#               log_file_daemon Place: the file name and path to be written.
#
#       syslog  To log each request via syslog facility.
#               Place: The syslog facility and priority level for these entries.
#               Place Format:  facility.priority
#
#               where facility could be any of:
#                       authpriv, daemon, local0 ... local7 or user.
#
#               And priority could be any of:
#                       err, warning, notice, info, debug.
#
#       udp     To send each log line as text data to a UDP receiver.
#               Place: The destination host name or IP and port.
#               Place Format:   //host:port
#
#       tcp     To send each log line as text data to a TCP receiver.
#               Lines may be accumulated before sending (see buffered_logs).
#               Place: The destination host name or IP and port.
#               Place Format:   //host:port
#
#       Default:
#               access_log daemon:/var/log/squid/access.log squid
#Default:
# access_log daemon:/var/log/squid/access.log squid

#  TAG: icap_log
#       ICAP log files record ICAP transaction summaries, one line per
#       transaction.
#
#       The icap_log option format is:
#       icap_log <filepath> [<logformat name> [acl acl ...]]
#       icap_log none [acl acl ...]]
#
#       Please see access_log option documentation for details. The two
#       kinds of logs share the overall configuration approach and many
#       features.
#
#       ICAP processing of a single HTTP message or transaction may
#       require multiple ICAP transactions.  In such cases, multiple
#       ICAP transaction log lines will correspond to a single access
#       log line.
#
#       ICAP log supports many access.log logformat %codes. In ICAP context,
#       HTTP message-related %codes are applied to the HTTP message embedded
#       in an ICAP message. Logformat "%http::>..." codes are used for HTTP
#       messages embedded in ICAP requests while "%http::<..." codes are used
#       for HTTP messages embedded in ICAP responses. For example:
#
#               http::>h        To-be-adapted HTTP message headers sent by Squid to
#                               the ICAP service. For REQMOD transactions, these are
#                               HTTP request headers. For RESPMOD, these are HTTP
#                               response headers, but Squid currently cannot log them
#                               (i.e., %http::>h will expand to "-" for RESPMOD).
#
#               http::<h        Adapted HTTP message headers sent by the ICAP
#                               service to Squid (i.e., HTTP request headers in regular
#                               REQMOD; HTTP response headers in RESPMOD and during
#                               request satisfaction in REQMOD).
#
#       ICAP OPTIONS transactions do not embed HTTP messages.
#
#       Several logformat codes below deal with ICAP message bodies. An ICAP
#       message body, if any, typically includes a complete HTTP message
#       (required HTTP headers plus optional HTTP message body). When
#       computing HTTP message body size for these logformat codes, Squid
#       either includes or excludes chunked encoding overheads; see
#       code-specific documentation for details.
#
#       For Secure ICAP services, all size-related information is currently
#       computed before/after TLS encryption/decryption, as if TLS was not
#       in use at all.
#
#       The following format codes are also available for ICAP logs:
#
#               icap::<A        ICAP server IP address. Similar to <A.
#
#               icap::<service_name     ICAP service name from the icap_service
#                               option in Squid configuration file.
#
#               icap::ru        ICAP Request-URI. Similar to ru.
#
#               icap::rm        ICAP request method (REQMOD, RESPMOD, or 
#                               OPTIONS). Similar to existing rm.
#
#               icap::>st       The total size of the ICAP request sent to the ICAP
#                               server (ICAP headers + ICAP body), including chunking
#                               metadata (if any).
#
#               icap::<st       The total size of the ICAP response received from the
#                               ICAP server (ICAP headers + ICAP body), including
#                               chunking metadata (if any).
#
#               icap::<bs       The size of the ICAP response body received from the
#                               ICAP server, excluding chunking metadata (if any).
#
#               icap::tr        Transaction response time (in
#                               milliseconds).  The timer starts when
#                               the ICAP transaction is created and
#                               stops when the transaction is completed.
#                               Similar to tr.
#
#               icap::tio       Transaction I/O time (in milliseconds). The
#                               timer starts when the first ICAP request
#                               byte is scheduled for sending. The timers
#                               stops when the last byte of the ICAP response
#                               is received.
#
#               icap::to        Transaction outcome: ICAP_ERR* for all
#                               transaction errors, ICAP_OPT for OPTION
#                               transactions, ICAP_ECHO for 204
#                               responses, ICAP_MOD for message
#                               modification, and ICAP_SAT for request
#                               satisfaction. Similar to Ss.
#
#               icap::Hs        ICAP response status code. Similar to Hs.
#
#               icap::>h        ICAP request header(s). Similar to >h.
#
#               icap::<h        ICAP response header(s). Similar to <h.
#
#       The default ICAP log format, which can be used without an explicit
#       definition, is called icap_squid:
#
#logformat icap_squid %ts.%03tu %6icap::tr %>A %icap::to/%03icap::Hs %icap::<st %icap::rm %icap::ru %un -/%icap::<A -
#
#       See also: logformat and %adapt::<last_h
#Default:
# none

#  TAG: logfile_daemon
#       Specify the path to the logfile-writing daemon. This daemon is
#       used to write the access and store logs, if configured.
#
#       Squid sends a number of commands to the log daemon:
#         L<data>\n - logfile data
#         R\n - rotate file
#         T\n - truncate file
#         O\n - reopen file
#         F\n - flush file
#         r<n>\n - set rotate count to <n>
#         b<n>\n - 1 = buffer output, 0 = don't buffer output
#
#       No responses is expected.
#Default:
# logfile_daemon /usr/lib/squid/log_file_daemon

#  TAG: stats_collection        allow|deny acl acl...
#       This options allows you to control which requests gets accounted
#       in performance counters.
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#Default:
# Allow logging for all transactions.

#  TAG: cache_store_log
#       Logs the activities of the storage manager.  Shows which
#       objects are ejected from the cache, and which objects are
#       saved and for how long.
#       There are not really utilities to analyze this data, so you can safely
#       disable it (the default).
#
#       Store log uses modular logging outputs. See access_log for the list
#       of modules supported.
#
#       Example:
#               cache_store_log stdio:/var/log/squid/store.log
#               cache_store_log daemon:/var/log/squid/store.log
#Default:
# none

#  TAG: cache_swap_state
#       Location for the cache "swap.state" file. This index file holds
#       the metadata of objects saved on disk.  It is used to rebuild
#       the cache during startup.  Normally this file resides in each
#       'cache_dir' directory, but you may specify an alternate
#       pathname here.  Note you must give a full filename, not just
#       a directory. Since this is the index for the whole object
#       list you CANNOT periodically rotate it!
#
#       If %s can be used in the file name it will be replaced with a
#       a representation of the cache_dir name where each / is replaced
#       with '.'. This is needed to allow adding/removing cache_dir
#       lines when cache_swap_log is being used.
#
#       If have more than one 'cache_dir', and %s is not used in the name
#       these swap logs will have names such as:
#
#               cache_swap_log.00
#               cache_swap_log.01
#               cache_swap_log.02
#
#       The numbered extension (which is added automatically)
#       corresponds to the order of the 'cache_dir' lines in this
#       configuration file.  If you change the order of the 'cache_dir'
#       lines in this file, these index files will NOT correspond to
#       the correct 'cache_dir' entry (unless you manually rename
#       them).  We recommend you do NOT use this option.  It is
#       better to keep these index files in each 'cache_dir' directory.
#Default:
# Store the journal inside its cache_dir

#  TAG: logfile_rotate
#       Specifies the default number of logfile rotations to make when you
#       type 'squid -k rotate'. The default is 10, which will rotate
#       with extensions 0 through 9. Setting logfile_rotate to 0 will
#       disable the file name rotation, but the logfiles are still closed
#       and re-opened. This will enable you to rename the logfiles
#       yourself just before sending the rotate signal.
#
#       Note, from Squid-3.1 this option is only a default for cache.log,
#       that log can be rotated separately by using debug_options.
#
#       Note, from Squid-4 this option is only a default for access.log
#       recorded by stdio: module. Those logs can be rotated separately by
#       using the rotate=N option on their access_log directive.
#
#       Note, the 'squid -k rotate' command normally sends a USR1
#       signal to the running squid process.  In certain situations
#       (e.g. on Linux with Async I/O), USR1 is used for other
#       purposes, so -k rotate uses another signal.  It is best to get
#       in the habit of using 'squid -k rotate' instead of 'kill -USR1
#       <pid>'.
#
#       Note, for Debian/Linux the default of logfile_rotate is
#       zero, since it includes external logfile-rotation methods.
#Default:
# logfile_rotate 0

#  TAG: mime_table
#       Path to Squid's icon configuration file.
#
#       You shouldn't need to change this, but the default file contains
#       examples and formatting information if you do.
#Default:
# mime_table /usr/share/squid/mime.conf

#  TAG: log_mime_hdrs   on|off
#       The Cache can record both the request and the response MIME
#       headers for each HTTP transaction.  The headers are encoded
#       safely and will appear as two bracketed fields at the end of
#       the access log (for either the native or httpd-emulated log
#       formats).  To enable this logging set log_mime_hdrs to 'on'.
#Default:
# log_mime_hdrs off

#  TAG: pid_filename
#       A filename to write the process-id to.  To disable, enter "none".
#Default:
# pid_filename /run/squid.pid

#  TAG: client_netmask
#       A netmask for client addresses in logfiles and cachemgr output.
#       Change this to protect the privacy of your cache clients.
#       A netmask of 255.255.255.0 will log all IP's in that range with
#       the last digit set to '0'.
#Default:
# Log full client IP address

#  TAG: strip_query_terms
#       By default, Squid strips query terms from requested URLs before
#       logging.  This protects your user's privacy and reduces log size.
#
#       When investigating HIT/MISS or other caching behaviour you
#       will need to disable this to see the full URL used by Squid.
#Default:
# strip_query_terms on

#  TAG: buffered_logs   on|off
#       Whether to write/send access_log records ASAP or accumulate them and
#       then write/send them in larger chunks. Buffering may improve
#       performance because it decreases the number of I/Os. However,
#       buffering increases the delay before log records become available to
#       the final recipient (e.g., a disk file or logging daemon) and,
#       hence, increases the risk of log records loss.
#
#       Note that even when buffered_logs are off, Squid may have to buffer
#       records if it cannot write/send them immediately due to pending I/Os
#       (e.g., the I/O writing the previous log record) or connectivity loss.
#
#       Currently honored by 'daemon' and 'tcp' access_log modules only.
#Default:
# buffered_logs off

#  TAG: netdb_filename
#       Where Squid stores it's netdb journal.
#       When enabled this journal preserves netdb state between restarts.
#
#       To disable, enter "none".
#Default:
# netdb_filename stdio:/var/spool/squid/netdb.state

# OPTIONS FOR TROUBLESHOOTING
# -----------------------------------------------------------------------------

#  TAG: cache_log
#       Squid administrative logging file.
#
#       This is where general information about Squid behavior goes. You can
#       increase the amount of data logged to this file and how often it is
#       rotated with "debug_options"
#Default:
# cache_log /var/log/squid/cache.log

#  TAG: debug_options
#       Logging options are set as section,level where each source file
#       is assigned a unique section.  Lower levels result in less
#       output,  Full debugging (level 9) can result in a very large
#       log file, so be careful.
#
#       The magic word "ALL" sets debugging levels for all sections.
#       The default is to run with "ALL,1" to record important warnings.
#
#       The rotate=N option can be used to keep more or less of these logs
#       than would otherwise be kept by logfile_rotate.
#       For most uses a single log should be enough to monitor current
#       events affecting Squid.
#Default:
# Log all critical and important messages.

#  TAG: coredump_dir
#       By default Squid leaves core files in the directory from where
#       it was started. If you set 'coredump_dir' to a directory
#       that exists, Squid will chdir() to that directory at startup
#       and coredump files will be left there.
#
#Default:
# Use the directory from where Squid was started.
#

# Leave coredumps in the first cache dir
coredump_dir /var/spool/squid

# OPTIONS FOR FTP GATEWAYING
# -----------------------------------------------------------------------------

#  TAG: ftp_user
#       If you want the anonymous login password to be more informative
#       (and enable the use of picky FTP servers), set this to something
#       reasonable for your domain, like wwwuser@somewhere.net
#
#       The reason why this is domainless by default is the
#       request can be made on the behalf of a user in any domain,
#       depending on how the cache is used.
#       Some FTP server also validate the email address is valid
#       (for example perl.com).
#Default:
# ftp_user Squid@

#  TAG: ftp_passive
#       If your firewall does not allow Squid to use passive
#       connections, turn off this option.
#
#       Use of ftp_epsv_all option requires this to be ON.
#Default:
# ftp_passive on

#  TAG: ftp_epsv_all
#       FTP Protocol extensions permit the use of a special "EPSV ALL" command.
#
#       NATs may be able to put the connection on a "fast path" through the
#       translator, as the EPRT command will never be used and therefore,
#       translation of the data portion of the segments will never be needed.
#
#       When a client only expects to do two-way FTP transfers this may be
#       useful.
#       If squid finds that it must do a three-way FTP transfer after issuing
#       an EPSV ALL command, the FTP session will fail.
#
#       If you have any doubts about this option do not use it.
#       Squid will nicely attempt all other connection methods.
#
#       Requires ftp_passive to be ON (default) for any effect.
#Default:
# ftp_epsv_all off

#  TAG: ftp_epsv
#       FTP Protocol extensions permit the use of a special "EPSV" command.
#
#       NATs may be able to put the connection on a "fast path" through the
#       translator using EPSV, as the EPRT command will never be used
#       and therefore, translation of the data portion of the segments 
#       will never be needed.
#
#       EPSV is often required to interoperate with FTP servers on IPv6
#       networks. On the other hand, it may break some IPv4 servers.
#
#       By default, EPSV may try EPSV with any FTP server. To fine tune
#       that decision, you may restrict EPSV to certain clients or servers
#       using ACLs:
#
#               ftp_epsv allow|deny al1 acl2 ...
#
#       WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
#
#       Only fast ACLs are supported.
#       Requires ftp_passive to be ON (default) for any effect.
#Default:
# none

#  TAG: ftp_eprt
#       FTP Protocol extensions permit the use of a special "EPRT" command.
#
#       This extension provides a protocol neutral alternative to the
#       IPv4-only PORT command. When supported it enables active FTP data
#       channels over IPv6 and efficient NAT handling.
#
#       Turning this OFF will prevent EPRT being attempted and will skip
#       straight to using PORT for IPv4 servers.
#
#       Some devices are known to not handle this extension correctly and
#       may result in crashes. Devices which suport EPRT enough to fail
#       cleanly will result in Squid attempting PORT anyway. This directive
#       should only be disabled when EPRT results in device failures.
#
#       WARNING: Doing so will convert Squid back to the old behavior with all
#       the related problems with external NAT devices/layers and IPv4-only FTP.
#Default:
# ftp_eprt on

#  TAG: ftp_sanitycheck
#       For security and data integrity reasons Squid by default performs
#       sanity checks of the addresses of FTP data connections ensure the
#       data connection is to the requested server. If you need to allow
#       FTP connections to servers using another IP address for the data
#       connection turn this off.
#Default:
# ftp_sanitycheck on

#  TAG: ftp_telnet_protocol
#       The FTP protocol is officially defined to use the telnet protocol
#       as transport channel for the control connection. However, many
#       implementations are broken and does not respect this aspect of
#       the FTP protocol.
#
#       If you have trouble accessing files with ASCII code 255 in the
#       path or similar problems involving this ASCII code you can
#       try setting this directive to off. If that helps, report to the
#       operator of the FTP server in question that their FTP server
#       is broken and does not follow the FTP standard.
#Default:
# ftp_telnet_protocol on

# OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
# -----------------------------------------------------------------------------

#  TAG: diskd_program
#       Specify the location of the diskd executable.
#       Note this is only useful if you have compiled in
#       diskd as one of the store io modules.
#Default:
# diskd_program /usr/lib/squid/diskd

#  TAG: unlinkd_program
#       Specify the location of the executable for file deletion process.
#Default:
# unlinkd_program /usr/lib/squid/unlinkd

#  TAG: pinger_program
#       Specify the location of the executable for the pinger process.
#Default:
# pinger_program /usr/lib/squid/pinger

#  TAG: pinger_enable
#       Control whether the pinger is active at run-time.
#       Enables turning ICMP pinger on and off with a simple
#       squid -k reconfigure.
#Default:
# pinger_enable on

# OPTIONS FOR URL REWRITING
# -----------------------------------------------------------------------------

#  TAG: url_rewrite_program
#       The name and command line parameters of an admin-provided executable
#       for redirecting clients or adjusting/replacing client request URLs.
#
#       This helper is consulted after the received request is cleared by
#       http_access and adapted using eICAP/ICAP services (if any). If the
#       helper does not redirect the client, Squid checks adapted_http_access
#       and may consult the cache or forward the request to the next hop.
#
#
#       For each request, the helper gets one line in the following format:
#
#         [channel-ID <SP>] request-URL [<SP> extras] <NL>
#
#       Use url_rewrite_extras to configure what Squid sends as 'extras'.
#
#
#       The helper must reply to each query using a single line:
#
#         [channel-ID <SP>] result [<SP> kv-pairs] <NL>
#
#       The result section must match exactly one of the following outcomes:
#
#         OK [status=30N] url="..."
#
#               Redirect the client to a URL supplied in the 'url' parameter.
#               Optional 'status' specifies the status code to send to the
#               client in Squid's HTTP redirect response. It must be one of
#               the standard HTTP redirect status codes: 301, 302, 303, 307,
#               or 308. When no specific status is requested, Squid uses 302.
#
#         OK rewrite-url="..."
#
#               Replace the current request URL with the one supplied in the
#               'rewrite-url' parameter. Squid fetches the resource specified
#               by the new URL and forwards the received response (or its
#               cached copy) to the client.
#
#               WARNING: Avoid rewriting URLs! When possible, redirect the
#               client using an "OK url=..." helper response instead.
#               Rewriting URLs may create inconsistent requests and/or break
#               synchronization between internal client and origin server
#               states, especially when URLs or other message parts contain
#               snippets of that state. For example, Squid does not adjust
#               Location headers and embedded URLs after the helper rewrites
#               the request URL.
#
#         OK
#               Keep the client request intact.
#
#         ERR
#               Keep the client request intact.
#
#         BH [message="..."]
#               A helper problem that should be reported to the Squid admin
#               via a level-1 cache.log message. The 'message' parameter is
#               reserved for specifying the log message.
#
#       In addition to the kv-pairs mentioned above, Squid also understands
#       the following optional kv-pairs in URL rewriter responses:
#
#         clt_conn_tag=TAG
#               Associates a TAG with the client TCP connection.
#
#               The clt_conn_tag=TAG pair is treated as a regular transaction
#               annotation for the current request and also annotates future
#               requests on the same client connection. A helper may update
#               the TAG during subsequent requests by returning a new kv-pair.
#
#
#       Helper messages contain the channel-ID part if and only if the
#       url_rewrite_children directive specifies positive concurrency. As a
#       channel-ID value, Squid sends a number between 0 and concurrency-1.
#       The helper must echo back the received channel-ID in its response.
#
#       By default, Squid does not use a URL rewriter.
#Default:
# none

#  TAG: url_rewrite_children
#       Specifies the maximum number of redirector processes that Squid may
#       spawn (numberofchildren) and several related options. Using too few of
#       these helper processes (a.k.a. "helpers") creates request queues.
#       Using too many helpers wastes your system resources.
#
#       Usage: numberofchildren [option]...
#
#       The startup= and idle= options allow some measure of skew in your
#       tuning.
#
#               startup=
#
#       Sets a minimum of how many processes are to be spawned when Squid
#       starts or reconfigures. When set to zero the first request will
#       cause spawning of the first child process to handle it.
#
#       Starting too few will cause an initial slowdown in traffic as Squid
#       attempts to simultaneously spawn enough processes to cope.
#
#               idle=
#
#       Sets a minimum of how many processes Squid is to try and keep available
#       at all times. When traffic begins to rise above what the existing
#       processes can handle this many more will be spawned up to the maximum
#       configured. A minimum setting of 1 is required.
#
#               concurrency=
#
#       The number of requests each redirector helper can handle in
#       parallel. Defaults to 0 which indicates the redirector
#       is a old-style single threaded redirector.
#
#       When this directive is set to a value >= 1 then the protocol
#       used to communicate with the helper is modified to include
#       an ID in front of the request/response. The ID from the request
#       must be echoed back with the response to that request.
#
#               queue-size=N
#
#       Sets the maximum number of queued requests. A request is queued when
#       no existing child can accept it due to concurrency limit and no new
#       child can be started due to numberofchildren limit. The default
#       maximum is zero if url_rewrite_bypass is enabled and
#       2*numberofchildren otherwise. If the queued requests exceed queue size
#       and redirector_bypass configuration option is set, then redirector is
#       bypassed. Otherwise, Squid is allowed to temporarily exceed the
#       configured maximum, marking the affected helper as "overloaded". If
#       the helper overload lasts more than 3 minutes, the action prescribed
#       by the on-persistent-overload option applies.
#
#               on-persistent-overload=action
#
#       Specifies Squid reaction to a new helper request arriving when the helper
#       has been overloaded for more that 3 minutes already. The number of queued
#       requests determines whether the helper is overloaded (see the queue-size
#       option).
#
#       Two actions are supported:
#
#         die   Squid worker quits. This is the default behavior.
#
#         ERR   Squid treats the helper request as if it was
#               immediately submitted, and the helper immediately
#               replied with an ERR response. This action has no effect
#               on the already queued and in-progress helper requests.
#Default:
# url_rewrite_children 20 startup=0 idle=1 concurrency=0

#  TAG: url_rewrite_host_header
#       To preserve same-origin security policies in browsers and
#       prevent Host: header forgery by redirectors Squid rewrites
#       any Host: header in redirected requests.
#
#       If you are running an accelerator this may not be a wanted
#       effect of a redirector. This directive enables you disable
#       Host: alteration in reverse-proxy traffic.
#
#       WARNING: Entries are cached on the result of the URL rewriting
#       process, so be careful if you have domain-virtual hosts.
#
#       WARNING: Squid and other software verifies the URL and Host
#       are matching, so be careful not to relay through other proxies
#       or inspecting firewalls with this disabled.
#Default:
# url_rewrite_host_header on

#  TAG: url_rewrite_access
#       If defined, this access list specifies which requests are
#       sent to the redirector processes.
#
#       This clause supports both fast and slow acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#Default:
# Allow, unless rules exist in squid.conf.

#  TAG: url_rewrite_bypass
#       When this is 'on', a request will not go through the
#       redirector if all the helpers are busy. If this is 'off' and the
#       redirector queue grows too large, the action is prescribed by the
#       on-persistent-overload option. You should only enable this if the
#       redirectors are not critical to your caching system. If you use
#       redirectors for access control, and you enable this option,
#       users may have access to pages they should not
#       be allowed to request.
#
#       Enabling this option sets the default url_rewrite_children queue-size
#       option value to 0.
#Default:
# url_rewrite_bypass off

#  TAG: url_rewrite_extras
#       Specifies a string to be append to request line format for the
#       rewriter helper. "Quoted" format values may contain spaces and
#       logformat %macros. In theory, any logformat %macro can be used.
#       In practice, a %macro expands as a dash (-) if the helper request is
#       sent before the required macro information is available to Squid.
#Default:
# url_rewrite_extras "%>a/%>A %un %>rm myip=%la myport=%lp"

#  TAG: url_rewrite_timeout
#       Squid times active requests to redirector. The timeout value and Squid
#       reaction to a timed out request are configurable using the following
#       format:
#
#       url_rewrite_timeout timeout time-units on_timeout=<action> [response=<quoted-response>]
#
#       supported timeout actions:
#               fail    Squid return a ERR_GATEWAY_FAILURE error page
#
#               bypass  Do not re-write the URL
#
#               retry   Send the lookup to the helper again
#
#               use_configured_response
#                       Use the <quoted-response> as helper response
#Default:
# Squid waits for the helper response forever

# OPTIONS FOR STORE ID
# -----------------------------------------------------------------------------

#  TAG: store_id_program
#       Specify the location of the executable StoreID helper to use.
#       Since they can perform almost any function there isn't one included.
#
#       For each requested URL, the helper will receive one line with the format
#
#         [channel-ID <SP>] URL [<SP> extras]<NL>
#
#
#       After processing the request the helper must reply using the following format:
#
#         [channel-ID <SP>] result [<SP> kv-pairs]
#
#       The result code can be:
#
#         OK store-id="..."
#               Use the StoreID supplied in 'store-id='.
#
#         ERR
#               The default is to use HTTP request URL as the store ID.
#
#         BH
#               An internal error occurred in the helper, preventing
#               a result being identified.
#
#       In addition to the above kv-pairs Squid also understands the following
#       optional kv-pairs received from URL rewriters:
#         clt_conn_tag=TAG
#               Associates a TAG with the client TCP connection.
#               Please see url_rewrite_program related documentation for this
#               kv-pair
#
#       Helper programs should be prepared to receive and possibly ignore
#       additional whitespace-separated tokens on each input line.
#
#       When using the concurrency= option the protocol is changed by
#       introducing a query channel tag in front of the request/response.
#       The query channel tag is a number between 0 and concurrency-1.
#       This value must be echoed back unchanged to Squid as the first part
#       of the response relating to its request.
#
#       NOTE: when using StoreID refresh_pattern will apply to the StoreID
#             returned from the helper and not the URL.
#
#       WARNING: Wrong StoreID value returned by a careless helper may result
#                in the wrong cached response returned to the user.
#
#       By default, a StoreID helper is not used.
#Default:
# none

#  TAG: store_id_extras
#        Specifies a string to be append to request line format for the
#        StoreId helper. "Quoted" format values may contain spaces and
#        logformat %macros. In theory, any logformat %macro can be used.
#        In practice, a %macro expands as a dash (-) if the helper request is
#        sent before the required macro information is available to Squid.
#Default:
# store_id_extras "%>a/%>A %un %>rm myip=%la myport=%lp"

#  TAG: store_id_children
#       Specifies the maximum number of StoreID helper processes that Squid
#       may spawn (numberofchildren) and several related options. Using
#       too few of these helper processes (a.k.a. "helpers") creates request
#       queues. Using too many helpers wastes your system resources.
#
#       Usage: numberofchildren [option]...
#
#       The startup= and idle= options allow some measure of skew in your
#       tuning.
#
#               startup=
#
#       Sets a minimum of how many processes are to be spawned when Squid
#       starts or reconfigures. When set to zero the first request will
#       cause spawning of the first child process to handle it.
#
#       Starting too few will cause an initial slowdown in traffic as Squid
#       attempts to simultaneously spawn enough processes to cope.
#
#               idle=
#
#       Sets a minimum of how many processes Squid is to try and keep available
#       at all times. When traffic begins to rise above what the existing
#       processes can handle this many more will be spawned up to the maximum
#       configured. A minimum setting of 1 is required.
#
#               concurrency=
#
#       The number of requests each storeID helper can handle in
#       parallel. Defaults to 0 which indicates the helper
#       is a old-style single threaded program.
#
#       When this directive is set to a value >= 1 then the protocol
#       used to communicate with the helper is modified to include
#       an ID in front of the request/response. The ID from the request
#       must be echoed back with the response to that request.
#
#               queue-size=N
#
#       Sets the maximum number of queued requests to N. A request is queued
#       when no existing child can accept it due to concurrency limit and no
#       new child can be started due to numberofchildren limit. The default
#       maximum is 2*numberofchildren. If the queued requests exceed queue
#       size and redirector_bypass configuration option is set, then
#       redirector is bypassed. Otherwise, Squid is allowed to temporarily
#       exceed the configured maximum, marking the affected helper as
#       "overloaded". If the helper overload lasts more than 3 minutes, the
#       action prescribed by the on-persistent-overload option applies.
#
#               on-persistent-overload=action
#
#       Specifies Squid reaction to a new helper request arriving when the helper
#       has been overloaded for more that 3 minutes already. The number of queued
#       requests determines whether the helper is overloaded (see the queue-size
#       option).
#
#       Two actions are supported:
#
#         die   Squid worker quits. This is the default behavior.
#
#         ERR   Squid treats the helper request as if it was
#               immediately submitted, and the helper immediately
#               replied with an ERR response. This action has no effect
#               on the already queued and in-progress helper requests.
#Default:
# store_id_children 20 startup=0 idle=1 concurrency=0

#  TAG: store_id_access
#       If defined, this access list specifies which requests are
#       sent to the StoreID processes.  By default all requests
#       are sent.
#
#       This clause supports both fast and slow acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#Default:
# Allow, unless rules exist in squid.conf.

#  TAG: store_id_bypass
#       When this is 'on', a request will not go through the
#       helper if all helpers are busy. If this is 'off' and the helper
#       queue grows too large, the action is prescribed by the
#       on-persistent-overload option. You should only enable this if the
#       helpers are not critical to your caching system. If you use
#       helpers for critical caching components, and you enable this 
#       option, users may not get objects from cache.
#       This options sets default queue-size option of the store_id_children
#       to 0.
#Default:
# store_id_bypass on

# OPTIONS FOR TUNING THE CACHE
# -----------------------------------------------------------------------------

#  TAG: cache
#       Requests denied by this directive will not be served from the cache
#       and their responses will not be stored in the cache. This directive
#       has no effect on other transactions and on already cached responses.
#
#       This clause supports both fast and slow acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#
#       This and the two other similar caching directives listed below are
#       checked at different transaction processing stages, have different
#       access to response information, affect different cache operations,
#       and differ in slow ACLs support:
#
#       * cache: Checked before Squid makes a hit/miss determination.
#               No access to reply information!
#               Denies both serving a hit and storing a miss.
#               Supports both fast and slow ACLs.
#       * send_hit: Checked after a hit was detected.
#               Has access to reply (hit) information.
#               Denies serving a hit only.
#               Supports fast ACLs only.
#       * store_miss: Checked before storing a cachable miss.
#               Has access to reply (miss) information.
#               Denies storing a miss only.
#               Supports fast ACLs only.
#
#       If you are not sure which of the three directives to use, apply the
#       following decision logic:
#
#       * If your ACL(s) are of slow type _and_ need response info, redesign.
#         Squid does not support that particular combination at this time.
#        Otherwise:
#       * If your directive ACL(s) are of slow type, use "cache"; and/or
#       * if your directive ACL(s) need no response info, use "cache".
#        Otherwise:
#       * If you do not want the response cached, use store_miss; and/or
#       * if you do not want a hit on a cached response, use send_hit.
#Default:
# By default, this directive is unused and has no effect.

#  TAG: send_hit
#       Responses denied by this directive will not be served from the cache
#       (but may still be cached, see store_miss). This directive has no
#       effect on the responses it allows and on the cached objects.
#
#       Please see the "cache" directive for a summary of differences among
#       store_miss, send_hit, and cache directives.
#
#       Unlike the "cache" directive, send_hit only supports fast acl
#       types.  See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#
#       For example:
#
#               # apply custom Store ID mapping to some URLs
#               acl MapMe dstdomain .c.example.com
#               store_id_program ...
#               store_id_access allow MapMe
#
#               # but prevent caching of special responses
#               # such as 302 redirects that cause StoreID loops
#               acl Ordinary http_status 200-299
#               store_miss deny MapMe !Ordinary
#
#               # and do not serve any previously stored special responses
#               # from the cache (in case they were already cached before
#               # the above store_miss rule was in effect).
#               send_hit deny MapMe !Ordinary
#Default:
# By default, this directive is unused and has no effect.

#  TAG: store_miss
#       Responses denied by this directive will not be cached (but may still
#       be served from the cache, see send_hit). This directive has no
#       effect on the responses it allows and on the already cached responses.
#
#       Please see the "cache" directive for a summary of differences among
#       store_miss, send_hit, and cache directives. See the
#       send_hit directive for a usage example.
#
#       Unlike the "cache" directive, store_miss only supports fast acl
#       types.  See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#Default:
# By default, this directive is unused and has no effect.

#  TAG: max_stale       time-units
#       This option puts an upper limit on how stale content Squid
#       will serve from the cache if cache validation fails.
#       Can be overriden by the refresh_pattern max-stale option.
#Default:
# max_stale 1 week

#  TAG: refresh_pattern
#       usage: refresh_pattern [-i] regex min percent max [options]
#
#       By default, regular expressions are CASE-SENSITIVE.  To make
#       them case-insensitive, use the -i option.
#
#       'Min' is the time (in minutes) an object without an explicit
#       expiry time should be considered fresh. The recommended
#       value is 0, any higher values may cause dynamic applications
#       to be erroneously cached unless the application designer
#       has taken the appropriate actions.
#
#       'Percent' is a percentage of the objects age (time since last
#       modification age) an object without explicit expiry time
#       will be considered fresh.
#
#       'Max' is an upper limit on how long objects without an explicit
#       expiry time will be considered fresh. The value is also used
#       to form Cache-Control: max-age header for a request sent from
#       Squid to origin/parent.
#
#       options: override-expire
#                override-lastmod
#                reload-into-ims
#                ignore-reload
#                ignore-no-store
#                ignore-private
#                max-stale=NN
#                refresh-ims
#                store-stale
#
#               override-expire enforces min age even if the server
#               sent an explicit expiry time (e.g., with the
#               Expires: header or Cache-Control: max-age). Doing this
#               VIOLATES the HTTP standard.  Enabling this feature
#               could make you liable for problems which it causes.
#
#               Note: override-expire does not enforce staleness - it only extends
#               freshness / min. If the server returns a Expires time which
#               is longer than your max time, Squid will still consider
#               the object fresh for that period of time.
#
#               override-lastmod enforces min age even on objects
#               that were modified recently.
#
#               reload-into-ims changes a client no-cache or ``reload''
#               request for a cached entry into a conditional request using
#               If-Modified-Since and/or If-None-Match headers, provided the
#               cached entry has a Last-Modified and/or a strong ETag header.
#               Doing this VIOLATES the HTTP standard. Enabling this feature
#               could make you liable for problems which it causes.
#
#               ignore-reload ignores a client no-cache or ``reload''
#               header. Doing this VIOLATES the HTTP standard. Enabling
#               this feature could make you liable for problems which
#               it causes.
#
#               ignore-no-store ignores any ``Cache-control: no-store''
#               headers received from a server. Doing this VIOLATES
#               the HTTP standard. Enabling this feature could make you
#               liable for problems which it causes.
#
#               ignore-private ignores any ``Cache-control: private''
#               headers received from a server. Doing this VIOLATES
#               the HTTP standard. Enabling this feature could make you
#               liable for problems which it causes.
#
#               refresh-ims causes squid to contact the origin server
#               when a client issues an If-Modified-Since request. This
#               ensures that the client will receive an updated version
#               if one is available.
#
#               store-stale stores responses even if they don't have explicit 
#               freshness or a validator (i.e., Last-Modified or an ETag) 
#               present, or if they're already stale. By default, Squid will 
#               not cache such responses because they usually can't be
#               reused. Note that such responses will be stale by default.
#
#               max-stale=NN provide a maximum staleness factor. Squid won't
#               serve objects more stale than this even if it failed to
#               validate the object. Default: use the max_stale global limit.
#
#       Basically a cached object is:
#
#               FRESH if expire > now, else STALE
#               STALE if age > max
#               FRESH if lm-factor < percent, else STALE
#               FRESH if age < min
#               else STALE
#
#       The refresh_pattern lines are checked in the order listed here.
#       The first entry which matches is used.  If none of the entries
#       match the default will be used.
#
#       Note, you must uncomment all the default lines if you want
#       to change one. The default setting is only active if none is
#       used.
#
#

#
# Add any of your own refresh_pattern entries above these.
#
refresh_pattern ^ftp:           1440    20%     10080
refresh_pattern ^gopher:        1440    0%      1440
refresh_pattern -i (/cgi-bin/|\?) 0     0%      0
refresh_pattern \/(Packages|Sources)(|\.bz2|\.gz|\.xz)$ 0 0% 0 refresh-ims
refresh_pattern \/Release(|\.gpg)$ 0 0% 0 refresh-ims
refresh_pattern \/InRelease$ 0 0% 0 refresh-ims
refresh_pattern \/(Translation-.*)(|\.bz2|\.gz|\.xz)$ 0 0% 0 refresh-ims
# example pattern for deb packages
#refresh_pattern (\.deb|\.udeb)$   129600 100% 129600
refresh_pattern .               0       20%     4320

#  TAG: quick_abort_min (KB)
#Default:
# quick_abort_min 16 KB

#  TAG: quick_abort_max (KB)
#Default:
# quick_abort_max 16 KB

#  TAG: quick_abort_pct (percent)
#       The cache by default continues downloading aborted requests
#       which are almost completed (less than 16 KB remaining). This
#       may be undesirable on slow (e.g. SLIP) links and/or very busy
#       caches.  Impatient users may tie up file descriptors and
#       bandwidth by repeatedly requesting and immediately aborting
#       downloads.
#
#       When the user aborts a request, Squid will check the
#       quick_abort values to the amount of data transferred until
#       then.
#
#       If the transfer has less than 'quick_abort_min' KB remaining,
#       it will finish the retrieval.
#
#       If the transfer has more than 'quick_abort_max' KB remaining,
#       it will abort the retrieval.
#
#       If more than 'quick_abort_pct' of the transfer has completed,
#       it will finish the retrieval.
#
#       If you do not want any retrieval to continue after the client
#       has aborted, set both 'quick_abort_min' and 'quick_abort_max'
#       to '0 KB'.
#
#       If you want retrievals to always continue if they are being
#       cached set 'quick_abort_min' to '-1 KB'.
#Default:
# quick_abort_pct 95

#  TAG: read_ahead_gap  buffer-size
#       The amount of data the cache will buffer ahead of what has been
#       sent to the client when retrieving an object from another server.
#Default:
# read_ahead_gap 16 KB

#  TAG: negative_ttl    time-units
#       Set the Default Time-to-Live (TTL) for failed requests.
#       Certain types of failures (such as "connection refused" and
#       "404 Not Found") are able to be negatively-cached for a short time.
#       Modern web servers should provide Expires: header, however if they
#       do not this can provide a minimum TTL.
#       The default is not to cache errors with unknown expiry details.
#
#       Note that this is different from negative caching of DNS lookups.
#
#       WARNING: Doing this VIOLATES the HTTP standard.  Enabling
#       this feature could make you liable for problems which it
#       causes.
#Default:
# negative_ttl 0 seconds

#  TAG: positive_dns_ttl        time-units
#       Upper limit on how long Squid will cache positive DNS responses.
#       Default is 6 hours (360 minutes). This directive must be set
#       larger than negative_dns_ttl.
#Default:
# positive_dns_ttl 6 hours

#  TAG: negative_dns_ttl        time-units
#       Time-to-Live (TTL) for negative caching of failed DNS lookups.
#       This also sets the lower cache limit on positive lookups.
#       Minimum value is 1 second, and it is not recommendable to go
#       much below 10 seconds.
#Default:
# negative_dns_ttl 1 minutes

#  TAG: range_offset_limit      size [acl acl...]
#       usage: (size) [units] [[!]aclname]
#
#       Sets an upper limit on how far (number of bytes) into the file 
#       a Range request may be to cause Squid to prefetch the whole file. 
#       If beyond this limit, Squid forwards the Range request as it is and 
#       the result is NOT cached.
#
#       This is to stop a far ahead range request (lets say start at 17MB)
#       from making Squid fetch the whole object up to that point before
#       sending anything to the client.
#
#       Multiple range_offset_limit lines may be specified, and they will 
#       be searched from top to bottom on each request until a match is found. 
#       The first match found will be used.  If no line matches a request, the 
#       default limit of 0 bytes will be used.
#
#       'size' is the limit specified as a number of units.
#
#       'units' specifies whether to use bytes, KB, MB, etc.
#       If no units are specified bytes are assumed.
#
#       A size of 0 causes Squid to never fetch more than the
#       client requested. (default)
#
#       A size of 'none' causes Squid to always fetch the object from the
#       beginning so it may cache the result. (2.0 style)
#
#       'aclname' is the name of a defined ACL.
#
#       NP: Using 'none' as the byte value here will override any quick_abort settings 
#           that may otherwise apply to the range request. The range request will
#           be fully fetched from start to finish regardless of the client
#           actions. This affects bandwidth usage.
#Default:
# none

#  TAG: minimum_expiry_time     (seconds)
#       The minimum caching time according to (Expires - Date)
#       headers Squid honors if the object can't be revalidated.
#       The default is 60 seconds.
#
#       In reverse proxy environments it might be desirable to honor
#       shorter object lifetimes. It is most likely better to make
#       your server return a meaningful Last-Modified header however.
#
#       In ESI environments where page fragments often have short
#       lifetimes, this will often be best set to 0.
#Default:
# minimum_expiry_time 60 seconds

#  TAG: store_avg_object_size   (bytes)
#       Average object size, used to estimate number of objects your
#       cache can hold.  The default is 13 KB.
#
#       This is used to pre-seed the cache index memory allocation to
#       reduce expensive reallocate operations while handling clients
#       traffic. Too-large values may result in memory allocation during
#       peak traffic, too-small values will result in wasted memory.
#
#       Check the cache manager 'info' report metrics for the real
#       object sizes seen by your Squid before tuning this.
#Default:
# store_avg_object_size 13 KB

#  TAG: store_objects_per_bucket
#       Target number of objects per bucket in the store hash table.
#       Lowering this value increases the total number of buckets and
#       also the storage maintenance rate.  The default is 20.
#Default:
# store_objects_per_bucket 20

# HTTP OPTIONS
# -----------------------------------------------------------------------------

#  TAG: request_header_max_size (KB)
#       This specifies the maximum size for HTTP headers in a request.
#       Request headers are usually relatively small (about 512 bytes).
#       Placing a limit on the request header size will catch certain
#       bugs (for example with persistent connections) and possibly
#       buffer-overflow or denial-of-service attacks.
#Default:
# request_header_max_size 64 KB

#  TAG: reply_header_max_size   (KB)
#       This specifies the maximum size for HTTP headers in a reply.
#       Reply headers are usually relatively small (about 512 bytes).
#       Placing a limit on the reply header size will catch certain
#       bugs (for example with persistent connections) and possibly
#       buffer-overflow or denial-of-service attacks.
#Default:
# reply_header_max_size 64 KB

#  TAG: request_body_max_size   (bytes)
#       This specifies the maximum size for an HTTP request body.
#       In other words, the maximum size of a PUT/POST request.
#       A user who attempts to send a request with a body larger
#       than this limit receives an "Invalid Request" error message.
#       If you set this parameter to a zero (the default), there will
#       be no limit imposed.
#
#       See also client_request_buffer_max_size for an alternative
#       limitation on client uploads which can be configured.
#Default:
# No limit.

#  TAG: client_request_buffer_max_size  (bytes)
#       This specifies the maximum buffer size of a client request.
#       It prevents squid eating too much memory when somebody uploads
#       a large file.
#Default:
# client_request_buffer_max_size 512 KB

#  TAG: broken_posts
#       A list of ACL elements which, if matched, causes Squid to send
#       an extra CRLF pair after the body of a PUT/POST request.
#
#       Some HTTP servers has broken implementations of PUT/POST,
#       and rely on an extra CRLF pair sent by some WWW clients.
#
#       Quote from RFC2616 section 4.1 on this matter:
#
#         Note: certain buggy HTTP/1.0 client implementations generate an
#         extra CRLF's after a POST request. To restate what is explicitly
#         forbidden by the BNF, an HTTP/1.1 client must not preface or follow
#         a request with an extra CRLF.
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#
#Example:
# acl buggy_server url_regex ^http://....
# broken_posts allow buggy_server
#Default:
# Obey RFC 2616.

#  TAG: adaptation_uses_indirect_client on|off
#       Controls whether the indirect client IP address (instead of the direct
#       client IP address) is passed to adaptation services.
#
#       See also: follow_x_forwarded_for adaptation_send_client_ip
#Default:
# adaptation_uses_indirect_client on

#  TAG: via     on|off
#       If set (default), Squid will include a Via header in requests and
#       replies as required by RFC2616.
#Default:
# via on

#  TAG: vary_ignore_expire      on|off
#       Many HTTP servers supporting Vary gives such objects
#       immediate expiry time with no cache-control header
#       when requested by a HTTP/1.0 client. This option
#       enables Squid to ignore such expiry times until
#       HTTP/1.1 is fully implemented.
#
#       WARNING: If turned on this may eventually cause some
#       varying objects not intended for caching to get cached.
#Default:
# vary_ignore_expire off

#  TAG: request_entities
#       Squid defaults to deny GET and HEAD requests with request entities,
#       as the meaning of such requests are undefined in the HTTP standard
#       even if not explicitly forbidden.
#
#       Set this directive to on if you have clients which insists
#       on sending request entities in GET or HEAD requests. But be warned
#       that there is server software (both proxies and web servers) which
#       can fail to properly process this kind of request which may make you
#       vulnerable to cache pollution attacks if enabled.
#Default:
# request_entities off

#  TAG: request_header_access
#       Usage: request_header_access header_name allow|deny [!]aclname ...
#
#       WARNING: Doing this VIOLATES the HTTP standard.  Enabling
#       this feature could make you liable for problems which it
#       causes.
#
#       This option replaces the old 'anonymize_headers' and the
#       older 'http_anonymizer' option with something that is much
#       more configurable. A list of ACLs for each header name allows
#       removal of specific header fields under specific conditions.
#
#       This option only applies to outgoing HTTP request headers (i.e.,
#       headers sent by Squid to the next HTTP hop such as a cache peer
#       or an origin server). The option has no effect during cache hit
#       detection. The equivalent adaptation vectoring point in ICAP
#       terminology is post-cache REQMOD.
#
#       The option is applied to individual outgoing request header
#       fields. For each request header field F, Squid uses the first
#       qualifying sets of request_header_access rules:
#
#           1. Rules with header_name equal to F's name.
#           2. Rules with header_name 'Other', provided F's name is not
#              on the hard-coded list of commonly used HTTP header names.
#           3. Rules with header_name 'All'.
#
#       Within that qualifying rule set, rule ACLs are checked as usual.
#       If ACLs of an "allow" rule match, the header field is allowed to
#       go through as is. If ACLs of a "deny" rule match, the header is
#       removed and request_header_replace is then checked to identify
#       if the removed header has a replacement. If no rules within the
#       set have matching ACLs, the header field is left as is.
#
#       For example, to achieve the same behavior as the old
#       'http_anonymizer standard' option, you should use:
#
#               request_header_access From deny all
#               request_header_access Referer deny all
#               request_header_access User-Agent deny all
#
#       Or, to reproduce the old 'http_anonymizer paranoid' feature
#       you should use:
#
#               request_header_access Authorization allow all
#               request_header_access Proxy-Authorization allow all
#               request_header_access Cache-Control allow all
#               request_header_access Content-Length allow all
#               request_header_access Content-Type allow all
#               request_header_access Date allow all
#               request_header_access Host allow all
#               request_header_access If-Modified-Since allow all
#               request_header_access Pragma allow all
#               request_header_access Accept allow all
#               request_header_access Accept-Charset allow all
#               request_header_access Accept-Encoding allow all
#               request_header_access Accept-Language allow all
#               request_header_access Connection allow all
#               request_header_access All deny all
#
#       HTTP reply headers are controlled with the reply_header_access directive.
#
#       By default, all headers are allowed (no anonymizing is performed).
#Default:
# No limits.

#  TAG: reply_header_access
#       Usage: reply_header_access header_name allow|deny [!]aclname ...
#
#       WARNING: Doing this VIOLATES the HTTP standard.  Enabling
#       this feature could make you liable for problems which it
#       causes.
#
#       This option only applies to reply headers, i.e., from the
#       server to the client.
#
#       This is the same as request_header_access, but in the other
#       direction. Please see request_header_access for detailed
#       documentation.
#
#       For example, to achieve the same behavior as the old
#       'http_anonymizer standard' option, you should use:
#
#               reply_header_access Server deny all
#               reply_header_access WWW-Authenticate deny all
#               reply_header_access Link deny all
#
#       Or, to reproduce the old 'http_anonymizer paranoid' feature
#       you should use:
#
#               reply_header_access Allow allow all
#               reply_header_access WWW-Authenticate allow all
#               reply_header_access Proxy-Authenticate allow all
#               reply_header_access Cache-Control allow all
#               reply_header_access Content-Encoding allow all
#               reply_header_access Content-Length allow all
#               reply_header_access Content-Type allow all
#               reply_header_access Date allow all
#               reply_header_access Expires allow all
#               reply_header_access Last-Modified allow all
#               reply_header_access Location allow all
#               reply_header_access Pragma allow all
#               reply_header_access Content-Language allow all
#               reply_header_access Retry-After allow all
#               reply_header_access Title allow all
#               reply_header_access Content-Disposition allow all
#               reply_header_access Connection allow all
#               reply_header_access All deny all
#
#       HTTP request headers are controlled with the request_header_access directive.
#
#       By default, all headers are allowed (no anonymizing is
#       performed).
#Default:
# No limits.

#  TAG: request_header_replace
#       Usage:   request_header_replace header_name message
#       Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
#
#       This option allows you to change the contents of headers
#       denied with request_header_access above, by replacing them
#       with some fixed string.
#
#       This only applies to request headers, not reply headers.
#
#       By default, headers are removed if denied.
#Default:
# none

#  TAG: reply_header_replace
#        Usage:   reply_header_replace header_name message
#        Example: reply_header_replace Server Foo/1.0
#
#        This option allows you to change the contents of headers
#        denied with reply_header_access above, by replacing them
#        with some fixed string.
#
#        This only applies to reply headers, not request headers.
#
#        By default, headers are removed if denied.
#Default:
# none

#  TAG: request_header_add
#       Usage:   request_header_add field-name field-value [ acl ... ]
#       Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
#
#       This option adds header fields to outgoing HTTP requests (i.e.,
#       request headers sent by Squid to the next HTTP hop such as a
#       cache peer or an origin server). The option has no effect during
#       cache hit detection. The equivalent adaptation vectoring point
#       in ICAP terminology is post-cache REQMOD.
#
#       Field-name is a token specifying an HTTP header name. If a
#       standard HTTP header name is used, Squid does not check whether
#       the new header conflicts with any existing headers or violates
#       HTTP rules. If the request to be modified already contains a
#       field with the same name, the old field is preserved but the
#       header field values are not merged.
#
#       Field-value is either a token or a quoted string. If quoted
#       string format is used, then the surrounding quotes are removed
#       while escape sequences and %macros are processed.
#
#       One or more Squid ACLs may be specified to restrict header
#       injection to matching requests. As always in squid.conf, all
#       ACLs in the ACL list must be satisfied for the insertion to
#       happen. The request_header_add supports fast ACLs only.
#
#       See also: reply_header_add.
#Default:
# none

#  TAG: reply_header_add
#       Usage:   reply_header_add field-name field-value [ acl ... ]
#       Example: reply_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
#
#       This option adds header fields to outgoing HTTP responses (i.e., response
#       headers delivered by Squid to the client). This option has no effect on
#       cache hit detection. The equivalent adaptation vectoring point in
#       ICAP terminology is post-cache RESPMOD. This option does not apply to
#       successful CONNECT replies.
#
#       Field-name is a token specifying an HTTP header name. If a
#       standard HTTP header name is used, Squid does not check whether
#       the new header conflicts with any existing headers or violates
#       HTTP rules. If the response to be modified already contains a
#       field with the same name, the old field is preserved but the
#       header field values are not merged.
#
#       Field-value is either a token or a quoted string. If quoted
#       string format is used, then the surrounding quotes are removed
#       while escape sequences and %macros are processed.
#
#       One or more Squid ACLs may be specified to restrict header
#       injection to matching responses. As always in squid.conf, all
#       ACLs in the ACL list must be satisfied for the insertion to
#       happen. The reply_header_add option supports fast ACLs only.
#
#       See also: request_header_add.
#Default:
# none

#  TAG: note
#       This option used to log custom information about the master
#       transaction. For example, an admin may configure Squid to log
#       which "user group" the transaction belongs to, where "user group"
#       will be determined based on a set of ACLs and not [just]
#       authentication information.
#       Values of key/value pairs can be logged using %{key}note macros:
#
#           note key value acl ...
#           logformat myFormat ... %{key}note ...
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#Default:
# none

#  TAG: relaxed_header_parser   on|off|warn
#       In the default "on" setting Squid accepts certain forms
#       of non-compliant HTTP messages where it is unambiguous
#       what the sending application intended even if the message
#       is not correctly formatted. The messages is then normalized
#       to the correct form when forwarded by Squid.
#
#       If set to "warn" then a warning will be emitted in cache.log
#       each time such HTTP error is encountered.
#
#       If set to "off" then such HTTP errors will cause the request
#       or response to be rejected.
#Default:
# relaxed_header_parser on

#  TAG: collapsed_forwarding    (on|off)
#       This option controls whether Squid is allowed to merge multiple
#       potentially cachable requests for the same URI before Squid knows
#       whether the response is going to be cachable.
#
#       When enabled, instead of forwarding each concurrent request for
#       the same URL, Squid just sends the first of them. The other, so
#       called "collapsed" requests, wait for the response to the first
#       request and, if it happens to be cachable, use that response.
#       Here, "concurrent requests" means "received after the first
#       request headers were parsed and before the corresponding response
#       headers were parsed".
#
#       This feature is disabled by default: enabling collapsed
#       forwarding needlessly delays forwarding requests that look
#       cachable (when they are collapsed) but then need to be forwarded
#       individually anyway because they end up being for uncachable
#       content. However, in some cases, such as acceleration of highly
#       cachable content with periodic or grouped expiration times, the
#       gains from collapsing [large volumes of simultaneous refresh
#       requests] outweigh losses from such delays.
#
#       Squid collapses two kinds of requests: regular client requests
#       received on one of the listening ports and internal "cache
#       revalidation" requests which are triggered by those regular
#       requests hitting a stale cached object. Revalidation collapsing
#       is currently disabled for Squid instances containing SMP-aware
#       disk or memory caches and for Vary-controlled cached objects.
#Default:
# collapsed_forwarding off

#  TAG: collapsed_forwarding_access
#       Use this directive to restrict collapsed forwarding to a subset of
#       eligible requests. The directive is checked for regular HTTP
#       requests, internal revalidation requests, and HTCP/ICP requests.
#
#               collapsed_forwarding_access allow|deny [!]aclname ...
#
#       This directive cannot force collapsing. It has no effect on
#       collapsing unless collapsed_forwarding is 'on', and all other
#       collapsing preconditions are satisfied.
#
#       * A denied request will not collapse, and future transactions will
#         not collapse on it (even if they are allowed to collapse).
#
#       * An allowed request may collapse, or future transactions may
#         collapse on it (provided they are allowed to collapse).
#
#       This directive is evaluated before receiving HTTP response headers
#       and without access to Squid-to-peer connection (if any).
#
#       Only fast ACLs are supported.
#
#       See also: collapsed_forwarding.
#Default:
# Requests may be collapsed if collapsed_forwarding is on.

#  TAG: shared_transient_entries_limit  (number of entries)
#       This directive limits the size of a table used for sharing current
#       transaction information among SMP workers. A table entry stores meta
#       information about a single cache entry being delivered to Squid
#       client(s) by one or more SMP workers. A single table entry consumes
#       less than 128 shared memory bytes.
#
#       The limit should be significantly larger than the number of
#       concurrent non-collapsed cachable responses leaving Squid. For a
#       cache that handles less than 5000 concurrent requests, the default
#       setting of 16384 should be plenty.
#
#       Using excessively large values wastes shared memory. Limiting the
#       table size too much results in hash collisions, leading to lower hit
#       ratio and missed SMP request collapsing opportunities: Transactions
#       left without a table entry cannot cache their responses and are
#       invisible to other concurrent requests for the same resource.
#
#       A zero limit is allowed but unsupported. A positive small limit
#       lowers hit ratio, but zero limit disables a lot of essential
#       synchronization among SMP workers, leading to HTTP violations (e.g.,
#       stale hit responses). It also disables shared collapsed forwarding:
#       A worker becomes unable to collapse its requests on transactions in
#       other workers, resulting in more trips to the origin server and more
#       cache thrashing.
#Default:
# shared_transient_entries_limit 16384

# TIMEOUTS
# -----------------------------------------------------------------------------

#  TAG: forward_timeout time-units
#       This parameter specifies how long Squid should at most attempt in
#       finding a forwarding path for the request before giving up.
#Default:
# forward_timeout 4 minutes

#  TAG: connect_timeout time-units
#       This parameter specifies how long to wait for the TCP connect to
#       the requested server or peer to complete before Squid should
#       attempt to find another path where to forward the request.
#Default:
# connect_timeout 1 minute

#  TAG: peer_connect_timeout    time-units
#       This parameter specifies how long to wait for a pending TCP
#       connection to a peer cache.  The default is 30 seconds.   You
#       may also set different timeout values for individual neighbors
#       with the 'connect-timeout' option on a 'cache_peer' line.
#Default:
# peer_connect_timeout 30 seconds

#  TAG: read_timeout    time-units
#       Applied on peer server connections.
#
#       After each successful read(), the timeout will be extended by this
#       amount.  If no data is read again after this amount of time,
#       the request is aborted and logged with ERR_READ_TIMEOUT.
#
#       The default is 15 minutes.
#Default:
# read_timeout 15 minutes

#  TAG: write_timeout   time-units
#       This timeout is tracked for all connections that have data
#       available for writing and are waiting for the socket to become
#       ready. After each successful write, the timeout is extended by
#       the configured amount. If Squid has data to write but the
#       connection is not ready for the configured duration, the
#       transaction associated with the connection is terminated. The
#       default is 15 minutes.
#Default:
# write_timeout 15 minutes

#  TAG: request_timeout
#       How long to wait for complete HTTP request headers after initial
#       connection establishment.
#Default:
# request_timeout 5 minutes

#  TAG: request_start_timeout
#       How long to wait for the first request byte after initial
#       connection establishment.
#Default:
# request_start_timeout 5 minutes

#  TAG: client_idle_pconn_timeout
#       How long to wait for the next HTTP request on a persistent
#       client connection after the previous request completes.
#Default:
# client_idle_pconn_timeout 2 minutes

#  TAG: ftp_client_idle_timeout
#       How long to wait for an FTP request on a connection to Squid ftp_port.
#       Many FTP clients do not deal with idle connection closures well,
#       necessitating a longer default timeout than client_idle_pconn_timeout
#       used for incoming HTTP requests.
#Default:
# ftp_client_idle_timeout 30 minutes

#  TAG: client_lifetime time-units
#       The maximum amount of time a client (browser) is allowed to
#       remain connected to the cache process.  This protects the Cache
#       from having a lot of sockets (and hence file descriptors) tied up
#       in a CLOSE_WAIT state from remote clients that go away without
#       properly shutting down (either because of a network failure or
#       because of a poor client implementation).  The default is one
#       day, 1440 minutes.
#
#       NOTE:  The default value is intended to be much larger than any
#       client would ever need to be connected to your cache.  You
#       should probably change client_lifetime only as a last resort.
#       If you seem to have many client connections tying up
#       filedescriptors, we recommend first tuning the read_timeout,
#       request_timeout, persistent_request_timeout and quick_abort values.
#Default:
# client_lifetime 1 day

#  TAG: pconn_lifetime  time-units
#       Desired maximum lifetime of a persistent connection.
#       When set, Squid will close a now-idle persistent connection that
#       exceeded configured lifetime instead of moving the connection into
#       the idle connection pool (or equivalent). No effect on ongoing/active
#       transactions. Connection lifetime is the time period from the
#       connection acceptance or opening time until "now".
#
#       This limit is useful in environments with long-lived connections
#       where Squid configuration or environmental factors change during a
#       single connection lifetime. If unrestricted, some connections may
#       last for hours and even days, ignoring those changes that should
#       have affected their behavior or their existence.
#
#       Currently, a new lifetime value supplied via Squid reconfiguration
#       has no effect on already idle connections unless they become busy.
#
#       When set to '0' this limit is not used.
#Default:
# pconn_lifetime 0 seconds

#  TAG: half_closed_clients
#       Some clients may shutdown the sending side of their TCP
#       connections, while leaving their receiving sides open.  Sometimes,
#       Squid can not tell the difference between a half-closed and a
#       fully-closed TCP connection.
#
#       By default, Squid will immediately close client connections when
#       read(2) returns "no more data to read."
#
#       Change this option to 'on' and Squid will keep open connections
#       until a read(2) or write(2) on the socket returns an error.
#       This may show some benefits for reverse proxies. But if not
#       it is recommended to leave OFF.
#Default:
# half_closed_clients off

#  TAG: server_idle_pconn_timeout
#       Timeout for idle persistent connections to servers and other
#       proxies.
#Default:
# server_idle_pconn_timeout 1 minute

#  TAG: ident_timeout
#       Maximum time to wait for IDENT lookups to complete.
#
#       If this is too high, and you enabled IDENT lookups from untrusted
#       users, you might be susceptible to denial-of-service by having
#       many ident requests going at once.
#Default:
# ident_timeout 10 seconds

#  TAG: shutdown_lifetime       time-units
#       When SIGTERM or SIGHUP is received, the cache is put into
#       "shutdown pending" mode until all active sockets are closed.
#       This value is the lifetime to set for all open descriptors
#       during shutdown mode.  Any active clients after this many
#       seconds will receive a 'timeout' message.
#Default:
# shutdown_lifetime 30 seconds

# ADMINISTRATIVE PARAMETERS
# -----------------------------------------------------------------------------

#  TAG: cache_mgr
#       Email-address of local cache manager who will receive
#       mail if the cache dies.  The default is "webmaster".
#Default:
# cache_mgr webmaster

#  TAG: mail_from
#       From: email-address for mail sent when the cache dies.
#       The default is to use 'squid@unique_hostname'.
#
#       See also: unique_hostname directive.
#Default:
# none

#  TAG: mail_program
#       Email program used to send mail if the cache dies.
#       The default is "mail". The specified program must comply
#       with the standard Unix mail syntax:
#         mail-program recipient < mailfile
#
#       Optional command line options can be specified.
#Default:
# mail_program mail

#  TAG: cache_effective_user
#       If you start Squid as root, it will change its effective/real
#       UID/GID to the user specified below.  The default is to change
#       to UID of proxy.
#       see also; cache_effective_group
#Default:
# cache_effective_user proxy

#  TAG: cache_effective_group
#       Squid sets the GID to the effective user's default group ID
#       (taken from the password file) and supplementary group list
#       from the groups membership.
#
#       If you want Squid to run with a specific GID regardless of
#       the group memberships of the effective user then set this
#       to the group (or GID) you want Squid to run as. When set
#       all other group privileges of the effective user are ignored
#       and only this GID is effective. If Squid is not started as
#       root the user starting Squid MUST be member of the specified
#       group.
#
#       This option is not recommended by the Squid Team.
#       Our preference is for administrators to configure a secure
#       user account for squid with UID/GID matching system policies.
#Default:
# Use system group memberships of the cache_effective_user account

#  TAG: httpd_suppress_version_string   on|off
#       Suppress Squid version string info in HTTP headers and HTML error pages.
#Default:
# httpd_suppress_version_string off

#  TAG: visible_hostname
#       If you want to present a special hostname in error messages, etc,
#       define this.  Otherwise, the return value of gethostname()
#       will be used. If you have multiple caches in a cluster and
#       get errors about IP-forwarding you must set them to have individual
#       names with this setting.
#Default:
# Automatically detect the system host name

#  TAG: unique_hostname
#       If you want to have multiple machines with the same
#       'visible_hostname' you must give each machine a different
#       'unique_hostname' so forwarding loops can be detected.
#Default:
# Copy the value from visible_hostname

#  TAG: hostname_aliases
#       A list of other DNS names your cache has.
#Default:
# none

#  TAG: umask
#       Minimum umask which should be enforced while the proxy
#       is running, in addition to the umask set at startup.
#
#       For a traditional octal representation of umasks, start
#        your value with 0.
#Default:
# umask 027

# OPTIONS FOR THE CACHE REGISTRATION SERVICE
# -----------------------------------------------------------------------------
#
#       This section contains parameters for the (optional) cache
#       announcement service.  This service is provided to help
#       cache administrators locate one another in order to join or
#       create cache hierarchies.
#
#       An 'announcement' message is sent (via UDP) to the registration
#       service by Squid.  By default, the announcement message is NOT
#       SENT unless you enable it with 'announce_period' below.
#
#       The announcement message includes your hostname, plus the
#       following information from this configuration file:
#
#               http_port
#               icp_port
#               cache_mgr
#
#       All current information is processed regularly and made
#       available on the Web at http://www.ircache.net/Cache/Tracker/.

#  TAG: announce_period
#       This is how frequently to send cache announcements.
#
#       To enable announcing your cache, just set an announce period.
#
#       Example:
#               announce_period 1 day
#Default:
# Announcement messages disabled.

#  TAG: announce_host
#       Set the hostname where announce registration messages will be sent.
#
#       See also announce_port and announce_file
#Default:
# announce_host tracker.ircache.net

#  TAG: announce_file
#       The contents of this file will be included in the announce
#       registration messages.
#Default:
# none

#  TAG: announce_port
#       Set the port where announce registration messages will be sent.
#
#       See also announce_host and announce_file
#Default:
# announce_port 3131

# HTTPD-ACCELERATOR OPTIONS
# -----------------------------------------------------------------------------

#  TAG: httpd_accel_surrogate_id
#       Surrogates (http://www.esi.org/architecture_spec_1.0.html)
#       need an identification token to allow control targeting. Because
#       a farm of surrogates may all perform the same tasks, they may share
#       an identification token.
#
#       When the surrogate is a reverse-proxy, this ID is also
#       used as cdn-id for CDN-Loop detection (RFC 8586).
#Default:
# visible_hostname is used if no specific ID is set.

#  TAG: http_accel_surrogate_remote     on|off
#       Remote surrogates (such as those in a CDN) honour the header
#       "Surrogate-Control: no-store-remote".
#
#       Set this to on to have squid behave as a remote surrogate.
#Default:
# http_accel_surrogate_remote off

#  TAG: esi_parser      libxml2|expat
#       Selects the XML parsing library to use when interpreting responses with
#       Edge Side Includes.
#
#       To disable ESI handling completely, ./configure Squid with --disable-esi.
#Default:
# Selects libxml2 if available at ./configure time or libexpat otherwise.

# DELAY POOL PARAMETERS
# -----------------------------------------------------------------------------

#  TAG: delay_pools
#       This represents the number of delay pools to be used.  For example,
#       if you have one class 2 delay pool and one class 3 delays pool, you
#       have a total of 2 delay pools.
#
#       See also delay_parameters, delay_class, delay_access for pool
#       configuration details.
#Default:
# delay_pools 0

#  TAG: delay_class
#       This defines the class of each delay pool.  There must be exactly one
#       delay_class line for each delay pool.  For example, to define two
#       delay pools, one of class 2 and one of class 3, the settings above
#       and here would be:
#
#       Example:
#           delay_pools 4      # 4 delay pools
#           delay_class 1 2    # pool 1 is a class 2 pool
#           delay_class 2 3    # pool 2 is a class 3 pool
#           delay_class 3 4    # pool 3 is a class 4 pool
#           delay_class 4 5    # pool 4 is a class 5 pool
#
#       The delay pool classes are:
#
#               class 1         Everything is limited by a single aggregate
#                               bucket.
#
#               class 2         Everything is limited by a single aggregate
#                               bucket as well as an "individual" bucket chosen
#                               from bits 25 through 32 of the IPv4 address.
#
#               class 3         Everything is limited by a single aggregate
#                               bucket as well as a "network" bucket chosen
#                               from bits 17 through 24 of the IP address and a
#                               "individual" bucket chosen from bits 17 through
#                               32 of the IPv4 address.
#
#               class 4         Everything in a class 3 delay pool, with an
#                               additional limit on a per user basis. This
#                               only takes effect if the username is established
#                               in advance - by forcing authentication in your
#                               http_access rules.
#
#               class 5         Requests are grouped according their tag (see
#                               external_acl's tag= reply).
#
#
#       Each pool also requires a delay_parameters directive to configure the pool size
#       and speed limits used whenever the pool is applied to a request. Along with
#       a set of delay_access directives to determine when it is used.
#
#       NOTE: If an IP address is a.b.c.d
#               -> bits 25 through 32 are "d"
#               -> bits 17 through 24 are "c"
#               -> bits 17 through 32 are "c * 256 + d"
#
#       NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
#               IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#
#       See also delay_parameters and delay_access.
#Default:
# none

#  TAG: delay_access
#       This is used to determine which delay pool a request falls into.
#
#       delay_access is sorted per pool and the matching starts with pool 1,
#       then pool 2, ..., and finally pool N. The first delay pool where the
#       request is allowed is selected for the request. If it does not allow
#       the request to any pool then the request is not delayed (default).
#
#       For example, if you want some_big_clients in delay
#       pool 1 and lotsa_little_clients in delay pool 2:
#
#               delay_access 1 allow some_big_clients
#               delay_access 1 deny all
#               delay_access 2 allow lotsa_little_clients
#               delay_access 2 deny all
#               delay_access 3 allow authenticated_clients
#
#       See also delay_parameters and delay_class.
#
#Default:
# Deny using the pool, unless allow rules exist in squid.conf for the pool.

#  TAG: delay_parameters
#       This defines the parameters for a delay pool.  Each delay pool has
#       a number of "buckets" associated with it, as explained in the
#       description of delay_class.
#
#       For a class 1 delay pool, the syntax is:
#               delay_class pool 1
#               delay_parameters pool aggregate
#
#       For a class 2 delay pool:
#               delay_class pool 2
#               delay_parameters pool aggregate individual
#
#       For a class 3 delay pool:
#               delay_class pool 3
#               delay_parameters pool aggregate network individual
#
#       For a class 4 delay pool:
#               delay_class pool 4
#               delay_parameters pool aggregate network individual user
#
#       For a class 5 delay pool:
#               delay_class pool 5
#               delay_parameters pool tagrate
#
#       The option variables are:
#
#               pool            a pool number - ie, a number between 1 and the
#                               number specified in delay_pools as used in
#                               delay_class lines.
#
#               aggregate       the speed limit parameters for the aggregate bucket
#                               (class 1, 2, 3).
#
#               individual      the speed limit parameters for the individual
#                               buckets (class 2, 3).
#
#               network         the speed limit parameters for the network buckets
#                               (class 3).
#
#               user            the speed limit parameters for the user buckets
#                               (class 4).
#
#               tagrate         the speed limit parameters for the tag buckets
#                               (class 5).
#
#       A pair of delay parameters is written restore/maximum, where restore is
#       the number of bytes (not bits - modem and network speeds are usually
#       quoted in bits) per second placed into the bucket, and maximum is the
#       maximum number of bytes which can be in the bucket at any time.
#
#       There must be one delay_parameters line for each delay pool.
#
#
#       For example, if delay pool number 1 is a class 2 delay pool as in the
#       above example, and is being used to strictly limit each host to 64Kbit/sec
#       (plus overheads), with no overall limit, the line is:
#
#               delay_parameters 1 none 8000/8000
#
#       Note that 8 x 8K Byte/sec -> 64K bit/sec.
#
#       Note that the word 'none' is used to represent no limit.
#
#
#       And, if delay pool number 2 is a class 3 delay pool as in the above
#       example, and you want to limit it to a total of 256Kbit/sec (strict limit)
#       with each 8-bit network permitted 64Kbit/sec (strict limit) and each
#       individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
#       to permit a decent web page to be downloaded at a decent speed
#       (if the network is not being limited due to overuse) but slow down
#       large downloads more significantly:
#
#               delay_parameters 2 32000/32000 8000/8000 600/8000
#
#       Note that 8 x  32K Byte/sec ->  256K bit/sec.
#                 8 x   8K Byte/sec ->   64K bit/sec.
#                 8 x 600  Byte/sec -> 4800  bit/sec.
#
#
#       Finally, for a class 4 delay pool as in the example - each user will
#       be limited to 128Kbits/sec no matter how many workstations they are logged into.:
#
#               delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
#
#
#       See also delay_class and delay_access.
#
#Default:
# none

#  TAG: delay_initial_bucket_level      (percent, 0-100)
#       The initial bucket percentage is used to determine how much is put
#       in each bucket when squid starts, is reconfigured, or first notices
#       a host accessing it (in class 2 and class 3, individual hosts and
#       networks only have buckets associated with them once they have been
#       "seen" by squid).
#Default:
# delay_initial_bucket_level 50

# CLIENT DELAY POOL PARAMETERS
# -----------------------------------------------------------------------------

#  TAG: client_delay_pools
#       This option specifies the number of client delay pools used. It must
#       preceed other client_delay_* options.
#
#       Example:
#               client_delay_pools 2
#
#       See also client_delay_parameters and client_delay_access.
#Default:
# client_delay_pools 0

#  TAG: client_delay_initial_bucket_level       (percent, 0-no_limit)
#       This option determines the initial bucket size as a percentage of
#       max_bucket_size from client_delay_parameters. Buckets are created
#       at the time of the "first" connection from the matching IP. Idle
#       buckets are periodically deleted up.
#
#       You can specify more than 100 percent but note that such "oversized"
#       buckets are not refilled until their size goes down to max_bucket_size
#       from client_delay_parameters.
#
#       Example:
#               client_delay_initial_bucket_level 50
#Default:
# client_delay_initial_bucket_level 50

#  TAG: client_delay_parameters
#
#       This option configures client-side bandwidth limits using the
#       following format:
#
#           client_delay_parameters pool speed_limit max_bucket_size
#
#       pool is an integer ID used for client_delay_access matching.
#
#       speed_limit is bytes added to the bucket per second.
#
#       max_bucket_size is the maximum size of a bucket, enforced after any
#       speed_limit additions.
#
#       Please see the delay_parameters option for more information and
#       examples.
#
#       Example:
#               client_delay_parameters 1 1024 2048
#               client_delay_parameters 2 51200 16384
#
#       See also client_delay_access.
#
#Default:
# none

#  TAG: client_delay_access
#       This option determines the client-side delay pool for the
#       request:
#
#           client_delay_access pool_ID allow|deny acl_name
#
#       All client_delay_access options are checked in their pool ID
#       order, starting with pool 1. The first checked pool with allowed
#       request is selected for the request. If no ACL matches or there
#       are no client_delay_access options, the request bandwidth is not
#       limited.
#
#       The ACL-selected pool is then used to find the
#       client_delay_parameters for the request. Client-side pools are
#       not used to aggregate clients. Clients are always aggregated
#       based on their source IP addresses (one bucket per source IP).
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#       Additionally, only the client TCP connection details are available.
#       ACLs testing HTTP properties will not work.
#
#       Please see delay_access for more examples.
#
#       Example:
#               client_delay_access 1 allow low_rate_network
#               client_delay_access 2 allow vips_network
#
#
#       See also client_delay_parameters and client_delay_pools.
#Default:
# Deny use of the pool, unless allow rules exist in squid.conf for the pool.

#  TAG: response_delay_pool
#       This option configures client response bandwidth limits using the
#       following format:
#
#       response_delay_pool name [option=value] ...
#
#       name    the response delay pool name
#
#       available options:
#
#               individual-restore      The speed limit of an individual
#                                       bucket(bytes/s). To be used in conjunction
#                                       with 'individual-maximum'.
#
#               individual-maximum      The maximum number of bytes which can
#                                       be placed into the individual bucket. To be used
#                                       in conjunction with 'individual-restore'.
#
#               aggregate-restore       The speed limit for the aggregate
#                                       bucket(bytes/s). To be used in conjunction with
#                                       'aggregate-maximum'.
#
#               aggregate-maximum       The maximum number of bytes which can
#                                       be placed into the aggregate bucket. To be used
#                                       in conjunction with 'aggregate-restore'.
#
#               initial-bucket-level    The initial bucket size as a percentage
#                                       of individual-maximum.
#
#       Individual and(or) aggregate bucket options may not be specified,
#       meaning no individual and(or) aggregate speed limitation.
#       See also response_delay_pool_access and delay_parameters for
#       terminology details.
#Default:
# none

#  TAG: response_delay_pool_access
#       Determines whether a specific named response delay pool is used
#       for the transaction. The syntax for this directive is:
#
#       response_delay_pool_access pool_name allow|deny acl_name
#
#       All response_delay_pool_access options are checked in the order
#       they appear in this configuration file. The first rule with a
#       matching ACL wins. If (and only if) an "allow" rule won, Squid
#       assigns the response to the corresponding named delay pool.
#Default:
# Deny use of the pool, unless allow rules exist in squid.conf for the pool.

# WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
# -----------------------------------------------------------------------------

#  TAG: wccp_router
#       Use this option to define your WCCP ``home'' router for
#       Squid.
#
#       wccp_router supports a single WCCP(v1) router
#
#       wccp2_router supports multiple WCCPv2 routers
#
#       only one of the two may be used at the same time and defines
#       which version of WCCP to use.
#Default:
# WCCP disabled.

#  TAG: wccp2_router
#       Use this option to define your WCCP ``home'' router for
#       Squid.
#
#       wccp_router supports a single WCCP(v1) router
#
#       wccp2_router supports multiple WCCPv2 routers
#
#       only one of the two may be used at the same time and defines
#       which version of WCCP to use.
#Default:
# WCCPv2 disabled.

#  TAG: wccp_version
#       This directive is only relevant if you need to set up WCCP(v1)
#       to some very old and end-of-life Cisco routers. In all other
#       setups it must be left unset or at the default setting.
#       It defines an internal version in the WCCP(v1) protocol,
#       with version 4 being the officially documented protocol.
#
#       According to some users, Cisco IOS 11.2 and earlier only
#       support WCCP version 3.  If you're using that or an earlier
#       version of IOS, you may need to change this value to 3, otherwise
#       do not specify this parameter.
#Default:
# wccp_version 4

#  TAG: wccp2_rebuild_wait
#       If this is enabled Squid will wait for the cache dir rebuild to finish
#       before sending the first wccp2 HereIAm packet
#Default:
# wccp2_rebuild_wait on

#  TAG: wccp2_forwarding_method
#       WCCP2 allows the setting of forwarding methods between the
#       router/switch and the cache.  Valid values are as follows:
#
#       gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
#       l2  - L2 redirect (forward the packet using Layer 2/MAC rewriting)
#
#       Currently (as of IOS 12.4) cisco routers only support GRE.
#       Cisco switches only support the L2 redirect assignment method.
#Default:
# wccp2_forwarding_method gre

#  TAG: wccp2_return_method
#       WCCP2 allows the setting of return methods between the
#       router/switch and the cache for packets that the cache
#       decides not to handle.  Valid values are as follows:
#
#       gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
#       l2  - L2 redirect (forward the packet using Layer 2/MAC rewriting)
#
#       Currently (as of IOS 12.4) cisco routers only support GRE.
#       Cisco switches only support the L2 redirect assignment.
#
#       If the "ip wccp redirect exclude in" command has been
#       enabled on the cache interface, then it is still safe for
#       the proxy server to use a l2 redirect method even if this
#       option is set to GRE.
#Default:
# wccp2_return_method gre

#  TAG: wccp2_assignment_method
#       WCCP2 allows the setting of methods to assign the WCCP hash
#       Valid values are as follows:
#
#       hash - Hash assignment
#       mask - Mask assignment
#
#       As a general rule, cisco routers support the hash assignment method
#       and cisco switches support the mask assignment method.
#Default:
# wccp2_assignment_method hash

#  TAG: wccp2_service
#       WCCP2 allows for multiple traffic services. There are two
#       types: "standard" and "dynamic". The standard type defines
#       one service id - http (id 0). The dynamic service ids can be from
#       51 to 255 inclusive.  In order to use a dynamic service id
#       one must define the type of traffic to be redirected; this is done
#       using the wccp2_service_info option.
#
#       The "standard" type does not require a wccp2_service_info option,
#       just specifying the service id will suffice.
#
#       MD5 service authentication can be enabled by adding
#       "password=<password>" to the end of this service declaration.
#
#       Examples:
#
#       wccp2_service standard 0        # for the 'web-cache' standard service
#       wccp2_service dynamic 80        # a dynamic service type which will be
#                                       # fleshed out with subsequent options.
#       wccp2_service standard 0 password=foo
#Default:
# Use the 'web-cache' standard service.

#  TAG: wccp2_service_info
#       Dynamic WCCPv2 services require further information to define the
#       traffic you wish to have diverted.
#
#       The format is:
#
#       wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
#           priority=<priority> ports=<port>,<port>..
#
#       The relevant WCCPv2 flags:
#       + src_ip_hash, dst_ip_hash
#       + source_port_hash, dst_port_hash
#       + src_ip_alt_hash, dst_ip_alt_hash
#       + src_port_alt_hash, dst_port_alt_hash
#       + ports_source
#
#       The port list can be one to eight entries.
#
#       Example:
#
#       wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
#           priority=240 ports=80
#
#       Note: the service id must have been defined by a previous
#       'wccp2_service dynamic <id>' entry.
#Default:
# none

#  TAG: wccp2_weight
#       Each cache server gets assigned a set of the destination
#       hash proportional to their weight.
#Default:
# wccp2_weight 10000

#  TAG: wccp_address
#       Use this option if you require WCCP(v1) to use a specific
#       interface address.
#
#       The default behavior is to not bind to any specific address.
#Default:
# Address selected by the operating system.

#  TAG: wccp2_address
#       Use this option if you require WCCPv2 to use a specific
#       interface address.
#
#       The default behavior is to not bind to any specific address.
#Default:
# Address selected by the operating system.

# PERSISTENT CONNECTION HANDLING
# -----------------------------------------------------------------------------
#
# Also see "pconn_timeout" in the TIMEOUTS section

#  TAG: client_persistent_connections
#       Persistent connection support for clients.
#       Squid uses persistent connections (when allowed). You can use
#       this option to disable persistent connections with clients.
#Default:
# client_persistent_connections on

#  TAG: server_persistent_connections
#       Persistent connection support for servers.
#       Squid uses persistent connections (when allowed). You can use
#       this option to disable persistent connections with servers.
#Default:
# server_persistent_connections on

#  TAG: persistent_connection_after_error
#       With this directive the use of persistent connections after
#       HTTP errors can be disabled. Useful if you have clients
#       who fail to handle errors on persistent connections proper.
#Default:
# persistent_connection_after_error on

#  TAG: detect_broken_pconn
#       Some servers have been found to incorrectly signal the use
#       of HTTP/1.0 persistent connections even on replies not
#       compatible, causing significant delays. This server problem
#       has mostly been seen on redirects.
#
#       By enabling this directive Squid attempts to detect such
#       broken replies and automatically assume the reply is finished
#       after 10 seconds timeout.
#Default:
# detect_broken_pconn off

# CACHE DIGEST OPTIONS
# -----------------------------------------------------------------------------

#  TAG: digest_generation
#       This controls whether the server will generate a Cache Digest
#       of its contents.  By default, Cache Digest generation is
#       enabled if Squid is compiled with --enable-cache-digests defined.
#Default:
# digest_generation on

#  TAG: digest_bits_per_entry
#       This is the number of bits of the server's Cache Digest which
#       will be associated with the Digest entry for a given HTTP
#       Method and URL (public key) combination.  The default is 5.
#Default:
# digest_bits_per_entry 5

#  TAG: digest_rebuild_period   (seconds)
#       This is the wait time between Cache Digest rebuilds.
#Default:
# digest_rebuild_period 1 hour

#  TAG: digest_rewrite_period   (seconds)
#       This is the wait time between Cache Digest writes to
#       disk.
#Default:
# digest_rewrite_period 1 hour

#  TAG: digest_swapout_chunk_size       (bytes)
#       This is the number of bytes of the Cache Digest to write to
#       disk at a time.  It defaults to 4096 bytes (4KB), the Squid
#       default swap page.
#Default:
# digest_swapout_chunk_size 4096 bytes

#  TAG: digest_rebuild_chunk_percentage (percent, 0-100)
#       This is the percentage of the Cache Digest to be scanned at a
#       time.  By default it is set to 10% of the Cache Digest.
#Default:
# digest_rebuild_chunk_percentage 10

# SNMP OPTIONS
# -----------------------------------------------------------------------------

#  TAG: snmp_port
#       The port number where Squid listens for SNMP requests. To enable
#       SNMP support set this to a suitable port number. Port number
#       3401 is often used for the Squid SNMP agent. By default it's
#       set to "0" (disabled)
#
#       Example:
#               snmp_port 3401
#Default:
# SNMP disabled.

#  TAG: snmp_access
#       Allowing or denying access to the SNMP port.
#
#       All access to the agent is denied by default.
#       usage:
#
#       snmp_access allow|deny [!]aclname ...
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#
#Example:
# snmp_access allow snmppublic localhost
# snmp_access deny all
#Default:
# Deny, unless rules exist in squid.conf.

#  TAG: snmp_incoming_address
#       Just like 'udp_incoming_address', but for the SNMP port.
#
#       snmp_incoming_address   is used for the SNMP socket receiving
#                               messages from SNMP agents.
#
#       The default snmp_incoming_address is to listen on all
#       available network interfaces.
#Default:
# Accept SNMP packets from all machine interfaces.

#  TAG: snmp_outgoing_address
#       Just like 'udp_outgoing_address', but for the SNMP port.
#
#       snmp_outgoing_address   is used for SNMP packets returned to SNMP
#                               agents.
#
#       If snmp_outgoing_address is not set it will use the same socket
#       as snmp_incoming_address. Only change this if you want to have
#       SNMP replies sent using another address than where this Squid
#       listens for SNMP queries.
#
#       NOTE, snmp_incoming_address and snmp_outgoing_address can not have
#       the same value since they both use the same port.
#Default:
# Use snmp_incoming_address or an address selected by the operating system.

# ICP OPTIONS
# -----------------------------------------------------------------------------

#  TAG: icp_port
#       The port number where Squid sends and receives ICP queries to
#       and from neighbor caches.  The standard UDP port for ICP is 3130.
#
#       Example:
#               icp_port 3130
#Default:
# ICP disabled.

#  TAG: htcp_port
#       The port number where Squid sends and receives HTCP queries to
#       and from neighbor caches.  To turn it on you want to set it to
#       4827.
#
#       Example:
#               htcp_port 4827
#Default:
# HTCP disabled.

#  TAG: log_icp_queries on|off
#       If set, ICP queries are logged to access.log. You may wish
#       do disable this if your ICP load is VERY high to speed things
#       up or to simplify log analysis.
#Default:
# log_icp_queries on

#  TAG: udp_incoming_address
#       udp_incoming_address    is used for UDP packets received from other
#                               caches.
#
#       The default behavior is to not bind to any specific address.
#
#       Only change this if you want to have all UDP queries received on
#       a specific interface/address.
#
#       NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
#       modules. Altering it will affect all of them in the same manner.
#
#       see also; udp_outgoing_address
#
#       NOTE, udp_incoming_address and udp_outgoing_address can not
#       have the same value since they both use the same port.
#Default:
# Accept packets from all machine interfaces.

#  TAG: udp_outgoing_address
#       udp_outgoing_address    is used for UDP packets sent out to other
#                               caches.
#
#       The default behavior is to not bind to any specific address.
#
#       Instead it will use the same socket as udp_incoming_address.
#       Only change this if you want to have UDP queries sent using another
#       address than where this Squid listens for UDP queries from other
#       caches.
#
#       NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
#       modules. Altering it will affect all of them in the same manner.
#
#       see also; udp_incoming_address
#
#       NOTE, udp_incoming_address and udp_outgoing_address can not
#       have the same value since they both use the same port.
#Default:
# Use udp_incoming_address or an address selected by the operating system.

#  TAG: icp_hit_stale   on|off
#       If you want to return ICP_HIT for stale cache objects, set this
#       option to 'on'.  If you have sibling relationships with caches
#       in other administrative domains, this should be 'off'.  If you only
#       have sibling relationships with caches under your control,
#       it is probably okay to set this to 'on'.
#       If set to 'on', your siblings should use the option "allow-miss"
#       on their cache_peer lines for connecting to you.
#Default:
# icp_hit_stale off

#  TAG: minimum_direct_hops
#       If using the ICMP pinging stuff, do direct fetches for sites
#       which are no more than this many hops away.
#Default:
# minimum_direct_hops 4

#  TAG: minimum_direct_rtt      (msec)
#       If using the ICMP pinging stuff, do direct fetches for sites
#       which are no more than this many rtt milliseconds away.
#Default:
# minimum_direct_rtt 400

#  TAG: netdb_low
#       The low water mark for the ICMP measurement database.
#
#       Note: high watermark controlled by netdb_high directive.
#
#       These watermarks are counts, not percents.  The defaults are
#       (low) 900 and (high) 1000.  When the high water mark is
#       reached, database entries will be deleted until the low
#       mark is reached.
#Default:
# netdb_low 900

#  TAG: netdb_high
#       The high water mark for the ICMP measurement database.
#
#       Note: low watermark controlled by netdb_low directive.
#
#       These watermarks are counts, not percents.  The defaults are
#       (low) 900 and (high) 1000.  When the high water mark is
#       reached, database entries will be deleted until the low
#       mark is reached.
#Default:
# netdb_high 1000

#  TAG: netdb_ping_period
#       The minimum period for measuring a site.  There will be at
#       least this much delay between successive pings to the same
#       network.  The default is five minutes.
#Default:
# netdb_ping_period 5 minutes

#  TAG: query_icmp      on|off
#       If you want to ask your peers to include ICMP data in their ICP
#       replies, enable this option.
#
#       If your peer has configured Squid (during compilation) with
#       '--enable-icmp' that peer will send ICMP pings to origin server
#       sites of the URLs it receives.  If you enable this option the
#       ICP replies from that peer will include the ICMP data (if available).
#       Then, when choosing a parent cache, Squid will choose the parent with
#       the minimal RTT to the origin server.  When this happens, the
#       hierarchy field of the access.log will be
#       "CLOSEST_PARENT_MISS".  This option is off by default.
#Default:
# query_icmp off

#  TAG: test_reachability       on|off
#       When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
#       instead of ICP_MISS if the target host is NOT in the ICMP
#       database, or has a zero RTT.
#Default:
# test_reachability off

#  TAG: icp_query_timeout       (msec)
#       Normally Squid will automatically determine an optimal ICP
#       query timeout value based on the round-trip-time of recent ICP
#       queries.  If you want to override the value determined by
#       Squid, set this 'icp_query_timeout' to a non-zero value.  This
#       value is specified in MILLISECONDS, so, to use a 2-second
#       timeout (the old default), you would write:
#
#               icp_query_timeout 2000
#Default:
# Dynamic detection.

#  TAG: maximum_icp_query_timeout       (msec)
#       Normally the ICP query timeout is determined dynamically.  But
#       sometimes it can lead to very large values (say 5 seconds).
#       Use this option to put an upper limit on the dynamic timeout
#       value.  Do NOT use this option to always use a fixed (instead
#       of a dynamic) timeout value. To set a fixed timeout see the
#       'icp_query_timeout' directive.
#Default:
# maximum_icp_query_timeout 2000

#  TAG: minimum_icp_query_timeout       (msec)
#       Normally the ICP query timeout is determined dynamically.  But
#       sometimes it can lead to very small timeouts, even lower than
#       the normal latency variance on your link due to traffic.
#       Use this option to put an lower limit on the dynamic timeout
#       value.  Do NOT use this option to always use a fixed (instead
#       of a dynamic) timeout value. To set a fixed timeout see the
#       'icp_query_timeout' directive.
#Default:
# minimum_icp_query_timeout 5

#  TAG: background_ping_rate    time-units
#       Controls how often the ICP pings are sent to siblings that
#       have background-ping set.
#Default:
# background_ping_rate 10 seconds

# MULTICAST ICP OPTIONS
# -----------------------------------------------------------------------------

#  TAG: mcast_groups
#       This tag specifies a list of multicast groups which your server
#       should join to receive multicasted ICP queries.
#
#       NOTE!  Be very careful what you put here!  Be sure you
#       understand the difference between an ICP _query_ and an ICP
#       _reply_.  This option is to be set only if you want to RECEIVE
#       multicast queries.  Do NOT set this option to SEND multicast
#       ICP (use cache_peer for that).  ICP replies are always sent via
#       unicast, so this option does not affect whether or not you will
#       receive replies from multicast group members.
#
#       You must be very careful to NOT use a multicast address which
#       is already in use by another group of caches.
#
#       If you are unsure about multicast, please read the Multicast
#       chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
#
#       Usage: mcast_groups 239.128.16.128 224.0.1.20
#
#       By default, Squid doesn't listen on any multicast groups.
#Default:
# none

#  TAG: mcast_miss_addr
# Note: This option is only available if Squid is rebuilt with the
#       -DMULTICAST_MISS_STREAM define
#
#       If you enable this option, every "cache miss" URL will
#       be sent out on the specified multicast address.
#
#       Do not enable this option unless you are are absolutely
#       certain you understand what you are doing.
#Default:
# disabled.

#  TAG: mcast_miss_ttl
# Note: This option is only available if Squid is rebuilt with the
#       -DMULTICAST_MISS_STREAM define
#
#       This is the time-to-live value for packets multicasted
#       when multicasting off cache miss URLs is enabled.  By
#       default this is set to 'site scope', i.e. 16.
#Default:
# mcast_miss_ttl 16

#  TAG: mcast_miss_port
# Note: This option is only available if Squid is rebuilt with the
#       -DMULTICAST_MISS_STREAM define
#
#       This is the port number to be used in conjunction with
#       'mcast_miss_addr'.
#Default:
# mcast_miss_port 3135

#  TAG: mcast_miss_encode_key
# Note: This option is only available if Squid is rebuilt with the
#       -DMULTICAST_MISS_STREAM define
#
#       The URLs that are sent in the multicast miss stream are
#       encrypted.  This is the encryption key.
#Default:
# mcast_miss_encode_key XXXXXXXXXXXXXXXX

#  TAG: mcast_icp_query_timeout (msec)
#       For multicast peers, Squid regularly sends out ICP "probes" to
#       count how many other peers are listening on the given multicast
#       address.  This value specifies how long Squid should wait to
#       count all the replies.  The default is 2000 msec, or 2
#       seconds.
#Default:
# mcast_icp_query_timeout 2000

# INTERNAL ICON OPTIONS
# -----------------------------------------------------------------------------

#  TAG: icon_directory
#       Where the icons are stored. These are normally kept in
#       /usr/share/squid/icons
#Default:
# icon_directory /usr/share/squid/icons

#  TAG: global_internal_static
#       This directive controls is Squid should intercept all requests for
#       /squid-internal-static/ no matter which host the URL is requesting
#       (default on setting), or if nothing special should be done for
#       such URLs (off setting). The purpose of this directive is to make
#       icons etc work better in complex cache hierarchies where it may
#       not always be possible for all corners in the cache mesh to reach
#       the server generating a directory listing.
#Default:
# global_internal_static on

#  TAG: short_icon_urls
#       If this is enabled Squid will use short URLs for icons.
#       If disabled it will revert to the old behavior of including
#       it's own name and port in the URL.
#
#       If you run a complex cache hierarchy with a mix of Squid and
#       other proxies you may need to disable this directive.
#Default:
# short_icon_urls on

# ERROR PAGE OPTIONS
# -----------------------------------------------------------------------------

#  TAG: error_directory
#       If you wish to create your own versions of the default
#       error files to customize them to suit your company copy
#       the error/template files to another directory and point
#       this tag at them.
#
#       WARNING: This option will disable multi-language support
#                on error pages if used.
#
#       The squid developers are interested in making squid available in
#       a wide variety of languages. If you are making translations for a
#       language that Squid does not currently provide please consider
#       contributing your translation back to the project.
#       http://wiki.squid-cache.org/Translations
#
#       The squid developers working on translations are happy to supply drop-in
#       translated error files in exchange for any new language contributions.
#Default:
# Send error pages in the clients preferred language

#  TAG: error_default_language
#       Set the default language which squid will send error pages in
#       if no existing translation matches the clients language
#       preferences.
#
#       If unset (default) generic English will be used.
#
#       The squid developers are interested in making squid available in
#       a wide variety of languages. If you are interested in making
#       translations for any language see the squid wiki for details.
#       http://wiki.squid-cache.org/Translations
#Default:
# Generate English language pages.

#  TAG: error_log_languages
#       Log to cache.log what languages users are attempting to
#       auto-negotiate for translations.
#
#       Successful negotiations are not logged. Only failures
#       have meaning to indicate that Squid may need an upgrade
#       of its error page translations.
#Default:
# error_log_languages on

#  TAG: err_page_stylesheet
#       CSS Stylesheet to pattern the display of Squid default error pages.
#
#       For information on CSS see http://www.w3.org/Style/CSS/
#Default:
# err_page_stylesheet /etc/squid/errorpage.css

#  TAG: err_html_text
#       HTML text to include in error messages.  Make this a "mailto"
#       URL to your admin address, or maybe just a link to your
#       organizations Web page.
#
#       To include this in your error messages, you must rewrite
#       the error template files (found in the "errors" directory).
#       Wherever you want the 'err_html_text' line to appear,
#       insert a %L tag in the error template file.
#Default:
# none

#  TAG: email_err_data  on|off
#       If enabled, information about the occurred error will be
#       included in the mailto links of the ERR pages (if %W is set)
#       so that the email body contains the data.
#       Syntax is <A HREF="mailto:%w%W">%w</A>
#Default:
# email_err_data on

#  TAG: deny_info
#       Usage:   deny_info err_page_name acl
#       or       deny_info http://... acl
#       or       deny_info TCP_RESET acl
#
#       This can be used to return a ERR_ page for requests which
#       do not pass the 'http_access' rules.  Squid remembers the last
#       acl it evaluated in http_access, and if a 'deny_info' line exists
#       for that ACL Squid returns a corresponding error page.
#
#       The acl is typically the last acl on the http_access deny line which
#       denied access. The exceptions to this rule are:
#       - When Squid needs to request authentication credentials. It's then
#         the first authentication related acl encountered
#       - When none of the http_access lines matches. It's then the last
#         acl processed on the last http_access line.
#       - When the decision to deny access was made by an adaptation service,
#         the acl name is the corresponding eCAP or ICAP service_name.
#
#       NP: If providing your own custom error pages with error_directory
#           you may also specify them by your custom file name:
#           Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
#
#       By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
#       may be specified by prefixing the file name with the code and a colon.
#       e.g. 404:ERR_CUSTOM_ACCESS_DENIED
#
#       Alternatively you can tell Squid to reset the TCP connection
#       by specifying TCP_RESET.
#
#       Or you can specify an error URL or URL pattern. The browsers will
#       get redirected to the specified URL after formatting tags have
#       been replaced. Redirect will be done with 302 or 307 according to
#       HTTP/1.1 specs. A different 3xx code may be specified by prefixing
#       the URL. e.g. 303:http://example.com/
#
#       URL FORMAT TAGS:
#               %a      - username (if available. Password NOT included)
#               %A      - Local listening IP address the client connection was connected to
#               %B      - FTP path URL
#               %e      - Error number
#               %E      - Error description
#               %h      - Squid hostname
#               %H      - Request domain name
#               %i      - Client IP Address
#               %M      - Request Method
#               %O      - Unescaped message result from external ACL helper
#               %o      - Message result from external ACL helper
#               %p      - Request Port number
#               %P      - Request Protocol name
#               %R      - Request URL path
#               %T      - Timestamp in RFC 1123 format
#               %U      - Full canonical URL from client
#                         (HTTPS URLs terminate with *)
#               %u      - Full canonical URL from client
#               %w      - Admin email from squid.conf
#               %x      - Error name
#               %%      - Literal percent (%) code
#
#Default:
# none

# OPTIONS INFLUENCING REQUEST FORWARDING 
# -----------------------------------------------------------------------------

#  TAG: nonhierarchical_direct
#       By default, Squid will send any non-hierarchical requests
#       (not cacheable request type) direct to origin servers.
#
#       When this is set to "off", Squid will prefer to send these
#       requests to parents.
#
#       Note that in most configurations, by turning this off you will only
#       add latency to these request without any improvement in global hit
#       ratio.
#
#       This option only sets a preference. If the parent is unavailable a
#       direct connection to the origin server may still be attempted. To
#       completely prevent direct connections use never_direct.
#Default:
# nonhierarchical_direct on

#  TAG: prefer_direct
#       Normally Squid tries to use parents for most requests. If you for some
#       reason like it to first try going direct and only use a parent if
#       going direct fails set this to on.
#
#       By combining nonhierarchical_direct off and prefer_direct on you
#       can set up Squid to use a parent as a backup path if going direct
#       fails.
#
#       Note: If you want Squid to use parents for all requests see
#       the never_direct directive. prefer_direct only modifies how Squid
#       acts on cacheable requests.
#Default:
# prefer_direct off

#  TAG: cache_miss_revalidate   on|off
#       RFC 7232 defines a conditional request mechanism to prevent
#       response objects being unnecessarily transferred over the network.
#       If that mechanism is used by the client and a cache MISS occurs
#       it can prevent new cache entries being created.
#
#       This option determines whether Squid on cache MISS will pass the
#       client revalidation request to the server or tries to fetch new
#       content for caching. It can be useful while the cache is mostly
#       empty to more quickly have the cache populated by generating
#       non-conditional GETs.
#
#       When set to 'on' (default), Squid will pass all client If-* headers
#       to the server. This permits server responses without a cacheable
#       payload to be delivered and on MISS no new cache entry is created.
#
#       When set to 'off' and if the request is cacheable, Squid will
#       remove the clients If-Modified-Since and If-None-Match headers from
#       the request sent to the server. This requests a 200 status response
#       from the server to create a new cache entry with.
#Default:
# cache_miss_revalidate on

#  TAG: always_direct
#       Usage: always_direct allow|deny [!]aclname ...
#
#       Here you can use ACL elements to specify requests which should
#       ALWAYS be forwarded by Squid to the origin servers without using
#       any peers.  For example, to always directly forward requests for
#       local servers ignoring any parents or siblings you may have use
#       something like:
#
#               acl local-servers dstdomain my.domain.net
#               always_direct allow local-servers
#
#       To always forward FTP requests directly, use
#
#               acl FTP proto FTP
#               always_direct allow FTP
#
#       NOTE: There is a similar, but opposite option named
#       'never_direct'.  You need to be aware that "always_direct deny
#       foo" is NOT the same thing as "never_direct allow foo".  You
#       may need to use a deny rule to exclude a more-specific case of
#       some other rule.  Example:
#
#               acl local-external dstdomain external.foo.net
#               acl local-servers dstdomain  .foo.net
#               always_direct deny local-external
#               always_direct allow local-servers
#
#       NOTE: If your goal is to make the client forward the request
#       directly to the origin server bypassing Squid then this needs
#       to be done in the client configuration. Squid configuration
#       can only tell Squid how Squid should fetch the object.
#
#       NOTE: This directive is not related to caching. The replies
#       is cached as usual even if you use always_direct. To not cache
#       the replies see the 'cache' directive.
#
#       This clause supports both fast and slow acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#Default:
# Prevent any cache_peer being used for this request.

#  TAG: never_direct
#       Usage: never_direct allow|deny [!]aclname ...
#
#       never_direct is the opposite of always_direct.  Please read
#       the description for always_direct if you have not already.
#
#       With 'never_direct' you can use ACL elements to specify
#       requests which should NEVER be forwarded directly to origin
#       servers.  For example, to force the use of a proxy for all
#       requests, except those in your local domain use something like:
#
#               acl local-servers dstdomain .foo.net
#               never_direct deny local-servers
#               never_direct allow all
#
#       or if Squid is inside a firewall and there are local intranet
#       servers inside the firewall use something like:
#
#               acl local-intranet dstdomain .foo.net
#               acl local-external dstdomain external.foo.net
#               always_direct deny local-external
#               always_direct allow local-intranet
#               never_direct allow all
#
#       This clause supports both fast and slow acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#Default:
# Allow DNS results to be used for this request.

# ADVANCED NETWORKING OPTIONS
# -----------------------------------------------------------------------------

#  TAG: incoming_udp_average
#       Heavy voodoo here.  I can't even believe you are reading this.
#       Are you crazy?  Don't even think about adjusting these unless
#       you understand the algorithms in comm_select.c first!
#Default:
# incoming_udp_average 6

#  TAG: incoming_tcp_average
#       Heavy voodoo here.  I can't even believe you are reading this.
#       Are you crazy?  Don't even think about adjusting these unless
#       you understand the algorithms in comm_select.c first!
#Default:
# incoming_tcp_average 4

#  TAG: incoming_dns_average
#       Heavy voodoo here.  I can't even believe you are reading this.
#       Are you crazy?  Don't even think about adjusting these unless
#       you understand the algorithms in comm_select.c first!
#Default:
# incoming_dns_average 4

#  TAG: min_udp_poll_cnt
#       Heavy voodoo here.  I can't even believe you are reading this.
#       Are you crazy?  Don't even think about adjusting these unless
#       you understand the algorithms in comm_select.c first!
#Default:
# min_udp_poll_cnt 8

#  TAG: min_dns_poll_cnt
#       Heavy voodoo here.  I can't even believe you are reading this.
#       Are you crazy?  Don't even think about adjusting these unless
#       you understand the algorithms in comm_select.c first!
#Default:
# min_dns_poll_cnt 8

#  TAG: min_tcp_poll_cnt
#       Heavy voodoo here.  I can't even believe you are reading this.
#       Are you crazy?  Don't even think about adjusting these unless
#       you understand the algorithms in comm_select.c first!
#Default:
# min_tcp_poll_cnt 8

#  TAG: accept_filter
#       FreeBSD:
#
#       The name of an accept(2) filter to install on Squid's
#       listen socket(s).  This feature is perhaps specific to
#       FreeBSD and requires support in the kernel.
#
#       The 'httpready' filter delays delivering new connections
#       to Squid until a full HTTP request has been received.
#       See the accf_http(9) man page for details.
#
#       The 'dataready' filter delays delivering new connections
#       to Squid until there is some data to process.
#       See the accf_dataready(9) man page for details.
#
#       Linux:
#
#       The 'data' filter delays delivering of new connections
#       to Squid until there is some data to process by TCP_ACCEPT_DEFER.
#       You may optionally specify a number of seconds to wait by
#       'data=N' where N is the number of seconds. Defaults to 30
#       if not specified.  See the tcp(7) man page for details.
#EXAMPLE:
## FreeBSD
#accept_filter httpready
## Linux
#accept_filter data
#Default:
# none

#  TAG: client_ip_max_connections
#       Set an absolute limit on the number of connections a single
#       client IP can use. Any more than this and Squid will begin to drop
#       new connections from the client until it closes some links.
#
#       Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
#       connections from the client. For finer control use the ACL access controls.
#
#       Requires client_db to be enabled (the default).
#
#       WARNING: This may noticably slow down traffic received via external proxies
#       or NAT devices and cause them to rebound error messages back to their clients.
#Default:
# No limit.

#  TAG: tcp_recv_bufsize        (bytes)
#       Size of receive buffer to set for TCP sockets.  Probably just
#       as easy to change your kernel's default.
#       Omit from squid.conf to use the default buffer size.
#Default:
# Use operating system TCP defaults.

# ICAP OPTIONS
# -----------------------------------------------------------------------------

#  TAG: icap_enable     on|off
#       If you want to enable the ICAP module support, set this to on.
#Default:
# icap_enable off

#  TAG: icap_connect_timeout
#       This parameter specifies how long to wait for the TCP connect to
#       the requested ICAP server to complete before giving up and either
#       terminating the HTTP transaction or bypassing the failure.
#
#       The default for optional services is peer_connect_timeout.
#       The default for essential services is connect_timeout.
#       If this option is explicitly set, its value applies to all services.
#Default:
# none

#  TAG: icap_io_timeout time-units
#       This parameter specifies how long to wait for an I/O activity on
#       an established, active ICAP connection before giving up and
#       either terminating the HTTP transaction or bypassing the
#       failure.
#Default:
# Use read_timeout.

#  TAG: icap_service_failure_limit      limit [in memory-depth time-units]
#       The limit specifies the number of failures that Squid tolerates
#       when establishing a new TCP connection with an ICAP service. If
#       the number of failures exceeds the limit, the ICAP service is
#       not used for new ICAP requests until it is time to refresh its
#       OPTIONS.
#
#       A negative value disables the limit. Without the limit, an ICAP
#       service will not be considered down due to connectivity failures
#       between ICAP OPTIONS requests.
#
#       Squid forgets ICAP service failures older than the specified
#       value of memory-depth. The memory fading algorithm 
#       is approximate because Squid does not remember individual 
#       errors but groups them instead, splitting the option
#       value into ten time slots of equal length.
#
#       When memory-depth is 0 and by default this option has no 
#       effect on service failure expiration.
#
#       Squid always forgets failures when updating service settings
#       using an ICAP OPTIONS transaction, regardless of this option
#       setting.
#
#       For example,
#               # suspend service usage after 10 failures in 5 seconds:
#               icap_service_failure_limit 10 in 5 seconds
#Default:
# icap_service_failure_limit 10

#  TAG: icap_service_revival_delay
#       The delay specifies the number of seconds to wait after an ICAP
#       OPTIONS request failure before requesting the options again. The
#       failed ICAP service is considered "down" until fresh OPTIONS are
#       fetched.
#
#       The actual delay cannot be smaller than the hardcoded minimum
#       delay of 30 seconds.
#Default:
# icap_service_revival_delay 180

#  TAG: icap_preview_enable     on|off
#       The ICAP Preview feature allows the ICAP server to handle the
#       HTTP message by looking only at the beginning of the message body
#       or even without receiving the body at all. In some environments, 
#       previews greatly speedup ICAP processing.
#
#       During an ICAP OPTIONS transaction, the server may tell Squid what
#       HTTP messages should be previewed and how big the preview should be.
#       Squid will not use Preview if the server did not request one.
#
#       To disable ICAP Preview for all ICAP services, regardless of
#       individual ICAP server OPTIONS responses, set this option to "off".
#Example:
#icap_preview_enable off
#Default:
# icap_preview_enable on

#  TAG: icap_preview_size
#       The default size of preview data to be sent to the ICAP server.
#       This value might be overwritten on a per server basis by OPTIONS requests.
#Default:
# No preview sent.

#  TAG: icap_206_enable on|off
#       206 (Partial Content) responses is an ICAP extension that allows the
#       ICAP agents to optionally combine adapted and original HTTP message
#       content. The decision to combine is postponed until the end of the
#       ICAP response. Squid supports Partial Content extension by default.
#
#       Activation of the Partial Content extension is negotiated with each
#       ICAP service during OPTIONS exchange. Most ICAP servers should handle
#       negotation correctly even if they do not support the extension, but
#       some might fail. To disable Partial Content support for all ICAP
#       services and to avoid any negotiation, set this option to "off".
#
#       Example:
#           icap_206_enable off
#Default:
# icap_206_enable on

#  TAG: icap_default_options_ttl
#       The default TTL value for ICAP OPTIONS responses that don't have
#       an Options-TTL header.
#Default:
# icap_default_options_ttl 60

#  TAG: icap_persistent_connections     on|off
#       Whether or not Squid should use persistent connections to
#       an ICAP server.
#Default:
# icap_persistent_connections on

#  TAG: adaptation_send_client_ip       on|off
#       If enabled, Squid shares HTTP client IP information with adaptation
#       services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
#       For eCAP, Squid sets the libecap::metaClientIp transaction option.
#
#       See also: adaptation_uses_indirect_client
#Default:
# adaptation_send_client_ip off

#  TAG: adaptation_send_username        on|off
#       This sends authenticated HTTP client username (if available) to
#       the adaptation service.
#
#       For ICAP, the username value is encoded based on the
#       icap_client_username_encode option and is sent using the header
#       specified by the icap_client_username_header option.
#Default:
# adaptation_send_username off

#  TAG: icap_client_username_header
#       ICAP request header name to use for adaptation_send_username.
#Default:
# icap_client_username_header X-Client-Username

#  TAG: icap_client_username_encode     on|off
#       Whether to base64 encode the authenticated client username.
#Default:
# icap_client_username_encode off

#  TAG: icap_service
#       Defines a single ICAP service using the following format:
#
#       icap_service id vectoring_point uri [option ...]
#
#       id: ID
#               an opaque identifier or name which is used to direct traffic to
#               this specific service. Must be unique among all adaptation
#               services in squid.conf.
#
#       vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
#               This specifies at which point of transaction processing the
#               ICAP service should be activated. *_postcache vectoring points
#               are not yet supported.
#
#       uri: icap://servername:port/servicepath
#               ICAP server and service location.
#            icaps://servername:port/servicepath
#               The "icap:" URI scheme is used for traditional ICAP server and
#               service location (default port is 1344, connections are not
#               encrypted). The "icaps:" URI scheme is for Secure ICAP
#               services that use SSL/TLS-encrypted ICAP connections (by
#               default, on port 11344).
#
#       ICAP does not allow a single service to handle both REQMOD and RESPMOD
#       transactions. Squid does not enforce that requirement. You can specify
#       services with the same service_url and different vectoring_points. You
#       can even specify multiple identical services as long as their
#       service_names differ.
#
#       To activate a service, use the adaptation_access directive. To group
#       services, use adaptation_service_chain and adaptation_service_set.
#
#       Service options are separated by white space. ICAP services support
#       the following name=value options:
#
#       bypass=on|off|1|0
#               If set to 'on' or '1', the ICAP service is treated as
#               optional. If the service cannot be reached or malfunctions,
#               Squid will try to ignore any errors and process the message as
#               if the service was not enabled. No all ICAP errors can be
#               bypassed.  If set to 0, the ICAP service is treated as
#               essential and all ICAP errors will result in an error page
#               returned to the HTTP client.
#
#               Bypass is off by default: services are treated as essential.
#
#       routing=on|off|1|0
#               If set to 'on' or '1', the ICAP service is allowed to
#               dynamically change the current message adaptation plan by
#               returning a chain of services to be used next. The services
#               are specified using the X-Next-Services ICAP response header
#               value, formatted as a comma-separated list of service names.
#               Each named service should be configured in squid.conf. Other
#               services are ignored. An empty X-Next-Services value results
#               in an empty plan which ends the current adaptation.
#
#               Dynamic adaptation plan may cross or cover multiple supported
#               vectoring points in their natural processing order.
#
#               Routing is not allowed by default: the ICAP X-Next-Services
#               response header is ignored.
#
#       ipv6=on|off
#               Only has effect on split-stack systems. The default on those systems
#               is to use IPv4-only connections. When set to 'on' this option will
#               make Squid use IPv6-only connections to contact this ICAP service.
#
#       on-overload=block|bypass|wait|force
#               If the service Max-Connections limit has been reached, do
#               one of the following for each new ICAP transaction:
#                 * block:  send an HTTP error response to the client
#                 * bypass: ignore the "over-connected" ICAP service
#                 * wait:   wait (in a FIFO queue) for an ICAP connection slot
#                 * force:  proceed, ignoring the Max-Connections limit 
#
#               In SMP mode with N workers, each worker assumes the service
#               connection limit is Max-Connections/N, even though not all
#               workers may use a given service.
#
#               The default value is "bypass" if service is bypassable,
#               otherwise it is set to "wait".
#
#
#       max-conn=number
#               Use the given number as the Max-Connections limit, regardless
#               of the Max-Connections value given by the service, if any.
#
#       connection-encryption=on|off
#               Determines the ICAP service effect on the connections_encrypted
#               ACL.
#
#               The default is "on" for Secure ICAP services (i.e., those
#               with the icaps:// service URIs scheme) and "off" for plain ICAP
#               services.
#
#               Does not affect ICAP connections (e.g., does not turn Secure
#               ICAP on or off).
#
#       ==== ICAPS / TLS OPTIONS ====
#
#       These options are used for Secure ICAP (icaps://....) services only.
#
#       tls-cert=/path/to/ssl/certificate
#                       A client X.509 certificate to use when connecting to
#                       this ICAP server.
#
#       tls-key=/path/to/ssl/key
#                       The private key corresponding to the previous
#                       tls-cert= option.
#
#                       If tls-key= is not specified tls-cert= is assumed to
#                       reference a PEM file containing both the certificate
#                       and private key.
#
#       tls-cipher=...  The list of valid TLS/SSL ciphers to use when connecting
#                       to this icap server.
#
#       tls-min-version=1.N
#                       The minimum TLS protocol version to permit. To control
#                       SSLv3 use the tls-options= parameter.
#                       Supported Values: 1.0 (default), 1.1, 1.2
#
#       tls-options=... Specify various OpenSSL library options:
#
#                           NO_SSLv3    Disallow the use of SSLv3
#
#                           SINGLE_DH_USE
#                                     Always create a new key when using
#                                     temporary/ephemeral DH key exchanges
#
#                           ALL       Enable various bug workarounds
#                                     suggested as "harmless" by OpenSSL
#                                     Be warned that this reduces SSL/TLS
#                                     strength to some attacks.
#
#                       See the OpenSSL SSL_CTX_set_options documentation for a
#                       more complete list. Options relevant only to SSLv2 are
#                       not supported.
#
#       tls-cafile=     PEM file containing CA certificates to use when verifying
#                       the icap server certificate.
#                       Use to specify intermediate CA certificate(s) if not sent
#                       by the server. Or the full CA chain for the server when
#                       using the tls-default-ca=off flag.
#                       May be repeated to load multiple files.
#
#       tls-capath=...  A directory containing additional CA certificates to
#                       use when verifying the icap server certificate.
#                       Requires OpenSSL or LibreSSL.
#
#       tls-crlfile=... A certificate revocation list file to use when
#                       verifying the icap server certificate.
#
#       tls-flags=...   Specify various flags modifying the Squid TLS implementation:
#
#                       DONT_VERIFY_PEER
#                               Accept certificates even if they fail to
#                               verify.
#                       DONT_VERIFY_DOMAIN
#                               Don't verify the icap server certificate
#                               matches the server name
#
#       tls-default-ca[=off]
#                       Whether to use the system Trusted CAs. Default is ON.
#
#       tls-domain=     The icap server name as advertised in it's certificate.
#                       Used for verifying the correctness of the received icap
#                       server certificate. If not specified the icap server
#                       hostname extracted from ICAP URI will be used.
#
#       Older icap_service format without optional named parameters is
#       deprecated but supported for backward compatibility.
#
#Example:
#icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
#icap_service svcLogger reqmod_precache icaps://icap2.mydomain.net:11344/reqmod routing=on
#Default:
# none

#  TAG: icap_class
#       This deprecated option was documented to define an ICAP service
#       chain, even though it actually defined a set of similar, redundant
#       services, and the chains were not supported. 
#
#       To define a set of redundant services, please use the
#       adaptation_service_set directive. For service chains, use
#       adaptation_service_chain.
#Default:
# none

#  TAG: icap_access
#       This option is deprecated. Please use adaptation_access, which
#       has the same ICAP functionality, but comes with better
#       documentation, and eCAP support.
#Default:
# none

# eCAP OPTIONS
# -----------------------------------------------------------------------------

#  TAG: ecap_enable     on|off
#       Controls whether eCAP support is enabled.
#Default:
# ecap_enable off

#  TAG: ecap_service
#       Defines a single eCAP service
#
#       ecap_service id vectoring_point uri [option ...]
#
#        id: ID
#               an opaque identifier or name which is used to direct traffic to
#               this specific service. Must be unique among all adaptation
#               services in squid.conf.
#
#       vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
#               This specifies at which point of transaction processing the
#               eCAP service should be activated. *_postcache vectoring points
#               are not yet supported.
#
#       uri: ecap://vendor/service_name?custom&cgi=style&parameters=optional
#               Squid uses the eCAP service URI to match this configuration
#               line with one of the dynamically loaded services. Each loaded
#               eCAP service must have a unique URI. Obtain the right URI from
#               the service provider.
#
#       To activate a service, use the adaptation_access directive. To group
#       services, use adaptation_service_chain and adaptation_service_set.
#
#       Service options are separated by white space. eCAP services support
#       the following name=value options:
#
#       bypass=on|off|1|0
#               If set to 'on' or '1', the eCAP service is treated as optional.
#               If the service cannot be reached or malfunctions, Squid will try
#               to ignore any errors and process the message as if the service
#               was not enabled. No all eCAP errors can be bypassed.
#               If set to 'off' or '0', the eCAP service is treated as essential
#               and all eCAP errors will result in an error page returned to the
#               HTTP client.
#
#                Bypass is off by default: services are treated as essential.
#
#       routing=on|off|1|0
#               If set to 'on' or '1', the eCAP service is allowed to
#               dynamically change the current message adaptation plan by
#               returning a chain of services to be used next.
#
#               Dynamic adaptation plan may cross or cover multiple supported
#               vectoring points in their natural processing order.
#
#               Routing is not allowed by default.
#
#       connection-encryption=on|off
#               Determines the eCAP service effect on the connections_encrypted
#               ACL. 
#
#               Defaults to "on", which does not taint the master transaction
#               w.r.t. that ACL.
#
#               Does not affect eCAP API calls.
#
#       Older ecap_service format without optional named parameters is
#       deprecated but supported for backward compatibility.
#
#
#Example:
#ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
#ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
#Default:
# none

#  TAG: loadable_modules
#       Instructs Squid to load the specified dynamic module(s) or activate
#       preloaded module(s).
#Example:
#loadable_modules /usr/lib/MinimalAdapter.so
#Default:
# none

# MESSAGE ADAPTATION OPTIONS
# -----------------------------------------------------------------------------

#  TAG: adaptation_service_set
#
#       Configures an ordered set of similar, redundant services. This is
#       useful when hot standby or backup adaptation servers are available.
#
#           adaptation_service_set set_name service_name1 service_name2 ...
#
#       The named services are used in the set declaration order. The first
#       applicable adaptation service from the set is used first. The next
#       applicable service is tried if and only if the transaction with the
#       previous service fails and the message waiting to be adapted is still
#       intact.
#
#       When adaptation starts, broken services are ignored as if they were
#       not a part of the set. A broken service is a down optional service.
#
#       The services in a set must be attached to the same vectoring point
#       (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
#
#       If all services in a set are optional then adaptation failures are
#       bypassable. If all services in the set are essential, then a
#       transaction failure with one service may still be retried using
#       another service from the set, but when all services fail, the master
#       transaction fails as well.
#
#       A set may contain a mix of optional and essential services, but that
#       is likely to lead to surprising results because broken services become
#       ignored (see above), making previously bypassable failures fatal.
#       Technically, it is the bypassability of the last failed service that
#       matters.
#
#       See also: adaptation_access adaptation_service_chain
#
#Example:
#adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
#adaptation service_set svcLogger loggerLocal loggerRemote
#Default:
# none

#  TAG: adaptation_service_chain
#
#       Configures a list of complementary services that will be applied
#       one-by-one, forming an adaptation chain or pipeline. This is useful
#       when Squid must perform different adaptations on the same message.
#
#           adaptation_service_chain chain_name service_name1 svc_name2 ...
#
#       The named services are used in the chain declaration order. The first
#       applicable adaptation service from the chain is used first. The next
#       applicable service is applied to the successful adaptation results of
#       the previous service in the chain.
#
#       When adaptation starts, broken services are ignored as if they were
#       not a part of the chain. A broken service is a down optional service.
#
#       Request satisfaction terminates the adaptation chain because Squid
#       does not currently allow declaration of RESPMOD services at the
#       "reqmod_precache" vectoring point (see icap_service or ecap_service).
#
#       The services in a chain must be attached to the same vectoring point
#       (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
#
#       A chain may contain a mix of optional and essential services. If an
#       essential adaptation fails (or the failure cannot be bypassed for
#       other reasons), the master transaction fails. Otherwise, the failure
#       is bypassed as if the failed adaptation service was not in the chain.
#
#       See also: adaptation_access adaptation_service_set
#
#Example:
#adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
#Default:
# none

#  TAG: adaptation_access
#       Sends an HTTP transaction to an ICAP or eCAP adaptation service.
#
#       adaptation_access service_name allow|deny [!]aclname...
#       adaptation_access set_name     allow|deny [!]aclname...
#
#       At each supported vectoring point, the adaptation_access
#       statements are processed in the order they appear in this
#       configuration file. Statements pointing to the following services
#       are ignored (i.e., skipped without checking their ACL):
#
#           - services serving different vectoring points
#           - "broken-but-bypassable" services
#           - "up" services configured to ignore such transactions
#              (e.g., based on the ICAP Transfer-Ignore header).
#
#        When a set_name is used, all services in the set are checked
#       using the same rules, to find the first applicable one. See
#       adaptation_service_set for details.
#
#       If an access list is checked and there is a match, the
#       processing stops: For an "allow" rule, the corresponding
#       adaptation service is used for the transaction. For a "deny"
#       rule, no adaptation service is activated.
#
#       It is currently not possible to apply more than one adaptation
#       service at the same vectoring point to the same HTTP transaction.
#
#        See also: icap_service and ecap_service
#
#Example:
#adaptation_access service_1 allow all
#Default:
# Allow, unless rules exist in squid.conf.

#  TAG: adaptation_service_iteration_limit
#       Limits the number of iterations allowed when applying adaptation
#       services to a message. If your longest adaptation set or chain
#       may have more than 16 services, increase the limit beyond its
#       default value of 16. If detecting infinite iteration loops sooner
#       is critical, make the iteration limit match the actual number
#       of services in your longest adaptation set or chain.
#
#       Infinite adaptation loops are most likely with routing services.
#
#       See also: icap_service routing=1
#Default:
# adaptation_service_iteration_limit 16

#  TAG: adaptation_masterx_shared_names
#       For each master transaction (i.e., the HTTP request and response
#       sequence, including all related ICAP and eCAP exchanges), Squid
#       maintains a table of metadata. The table entries are (name, value)
#       pairs shared among eCAP and ICAP exchanges. The table is destroyed
#       with the master transaction.
#
#       This option specifies the table entry names that Squid must accept
#       from and forward to the adaptation transactions.
#
#       An ICAP REQMOD or RESPMOD transaction may set an entry in the 
#       shared table by returning an ICAP header field with a name 
#       specified in adaptation_masterx_shared_names.
#
#       An eCAP REQMOD or RESPMOD transaction may set an entry in the
#       shared table by implementing the libecap::visitEachOption() API
#       to provide an option with a name specified in
#       adaptation_masterx_shared_names.
#
#       Squid will store and forward the set entry to subsequent adaptation
#       transactions within the same master transaction scope.
#
#       Only one shared entry name is supported at this time.
#
#Example:
## share authentication information among ICAP services
#adaptation_masterx_shared_names X-Subscriber-ID
#Default:
# none

#  TAG: adaptation_meta
#       This option allows Squid administrator to add custom ICAP request
#       headers or eCAP options to Squid ICAP requests or eCAP transactions.
#       Use it to pass custom authentication tokens and other
#       transaction-state related meta information to an ICAP/eCAP service.
#
#       The addition of a meta header is ACL-driven:
#               adaptation_meta name value [!]aclname ...
#
#       Processing for a given header name stops after the first ACL list match.
#       Thus, it is impossible to add two headers with the same name. If no ACL
#       lists match for a given header name, no such header is added. For 
#       example:
#
#               # do not debug transactions except for those that need debugging
#               adaptation_meta X-Debug 1 needs_debugging
#
#               # log all transactions except for those that must remain secret
#               adaptation_meta X-Log 1 !keep_secret
#
#               # mark transactions from users in the "G 1" group
#               adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
#
#       The "value" parameter may be a regular squid.conf token or a "double
#       quoted string". Within the quoted string, use backslash (\) to escape
#       any character, which is currently only useful for escaping backslashes
#       and double quotes. For example,
#           "this string has one backslash (\\) and two \"quotes\""
#
#       Used adaptation_meta header values may be logged via %note
#       logformat code. If multiple adaptation_meta headers with the same name
#       are used during master transaction lifetime, the header values are
#       logged in the order they were used and duplicate values are ignored
#       (only the first repeated value will be logged).
#Default:
# none

#  TAG: icap_retry
#       This ACL determines which retriable ICAP transactions are
#       retried. Transactions that received a complete ICAP response
#       and did not have to consume or produce HTTP bodies to receive
#       that response are usually retriable.
#
#       icap_retry allow|deny [!]aclname ...
#
#       Squid automatically retries some ICAP I/O timeouts and errors
#       due to persistent connection race conditions.
#
#       See also: icap_retry_limit
#Default:
# icap_retry deny all

#  TAG: icap_retry_limit
#       Limits the number of retries allowed.
#
#       Communication errors due to persistent connection race
#       conditions are unavoidable, automatically retried, and do not
#       count against this limit.
#
#       See also: icap_retry
#Default:
# No retries are allowed.

# DNS OPTIONS
# -----------------------------------------------------------------------------

#  TAG: check_hostnames
#       For security and stability reasons Squid can check
#       hostnames for Internet standard RFC compliance. If you want
#       Squid to perform these checks turn this directive on.
#Default:
# check_hostnames off

#  TAG: allow_underscore
#       Underscore characters is not strictly allowed in Internet hostnames
#       but nevertheless used by many sites. Set this to off if you want
#       Squid to be strict about the standard.
#       This check is performed only when check_hostnames is set to on.
#Default:
# allow_underscore on

#  TAG: dns_retransmit_interval
#       Initial retransmit interval for DNS queries. The interval is
#       doubled each time all configured DNS servers have been tried.
#Default:
# dns_retransmit_interval 5 seconds

#  TAG: dns_timeout
#       DNS Query timeout. If no response is received to a DNS query
#       within this time all DNS servers for the queried domain
#       are assumed to be unavailable.
#Default:
# dns_timeout 30 seconds

#  TAG: dns_packet_max
#       Maximum number of bytes packet size to advertise via EDNS.
#       Set to "none" to disable EDNS large packet support.
#
#       For legacy reasons DNS UDP replies will default to 512 bytes which
#       is too small for many responses. EDNS provides a means for Squid to
#       negotiate receiving larger responses back immediately without having
#       to failover with repeat requests. Responses larger than this limit
#       will retain the old behaviour of failover to TCP DNS.
#
#       Squid has no real fixed limit internally, but allowing packet sizes
#       over 1500 bytes requires network jumbogram support and is usually not
#       necessary.
#
#       WARNING: The RFC also indicates that some older resolvers will reply
#       with failure of the whole request if the extension is added. Some
#       resolvers have already been identified which will reply with mangled
#       EDNS response on occasion. Usually in response to many-KB jumbogram
#       sizes being advertised by Squid.
#       Squid will currently treat these both as an unable-to-resolve domain
#       even if it would be resolvable without EDNS.
#Default:
# EDNS disabled

#  TAG: dns_defnames    on|off
#       Normally the RES_DEFNAMES resolver option is disabled
#       (see res_init(3)).  This prevents caches in a hierarchy
#       from interpreting single-component hostnames locally.  To allow
#       Squid to handle single-component names, enable this option.
#Default:
# Search for single-label domain names is disabled.

#  TAG: dns_multicast_local     on|off
#       When set to on, Squid sends multicast DNS lookups on the local
#       network for domains ending in .local and .arpa.
#       This enables local servers and devices to be contacted in an
#       ad-hoc or zero-configuration network environment.
#Default:
# Search for .local and .arpa names is disabled.

#  TAG: dns_nameservers
#       Use this if you want to specify a list of DNS name servers
#       (IP addresses) to use instead of those given in your
#       /etc/resolv.conf file.
#
#       On Windows platforms, if no value is specified here or in
#       the /etc/resolv.conf file, the list of DNS name servers are
#       taken from the Windows registry, both static and dynamic DHCP
#       configurations are supported.
#
#       Example: dns_nameservers 10.0.0.1 192.172.0.4
#Default:
# Use operating system definitions

#  TAG: hosts_file
#       Location of the host-local IP name-address associations
#       database. Most Operating Systems have such a file on different
#       default locations:
#       - Un*X & Linux:    /etc/hosts
#       - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
#                          (%SystemRoot% value install default is c:\winnt)
#       - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
#                          (%SystemRoot% value install default is c:\windows)
#       - Windows 9x/Me:   %windir%\hosts
#                          (%windir% value is usually c:\windows)
#       - Cygwin:          /etc/hosts
#
#       The file contains newline-separated definitions, in the
#       form ip_address_in_dotted_form name [name ...] names are
#       whitespace-separated. Lines beginning with an hash (#)
#       character are comments.
#
#       The file is checked at startup and upon configuration.
#       If set to 'none', it won't be checked.
#       If append_domain is used, that domain will be added to
#       domain-local (i.e. not containing any dot character) host
#       definitions.
#Default:
# hosts_file /etc/hosts

#  TAG: append_domain
#       Appends local domain name to hostnames without any dots in
#       them.  append_domain must begin with a period.
#
#       Be warned there are now Internet names with no dots in
#       them using only top-domain names, so setting this may
#       cause some Internet sites to become unavailable.
#
#Example:
# append_domain .yourdomain.com
#Default:
# Use operating system definitions

#  TAG: ignore_unknown_nameservers
#       By default Squid checks that DNS responses are received
#       from the same IP addresses they are sent to.  If they
#       don't match, Squid ignores the response and writes a warning
#       message to cache.log.  You can allow responses from unknown
#       nameservers by setting this option to 'off'.
#Default:
# ignore_unknown_nameservers on

#  TAG: ipcache_size    (number of entries)
#       Maximum number of DNS IP cache entries.
#Default:
# ipcache_size 1024

#  TAG: ipcache_low     (percent)
#Default:
# ipcache_low 90

#  TAG: ipcache_high    (percent)
#       The size, low-, and high-water marks for the IP cache.
#Default:
# ipcache_high 95

#  TAG: fqdncache_size  (number of entries)
#       Maximum number of FQDN cache entries.
#Default:
# fqdncache_size 1024

# MISCELLANEOUS
# -----------------------------------------------------------------------------

#  TAG: configuration_includes_quoted_values    on|off
#       If set, Squid will recognize each "quoted string" after a configuration
#       directive as a single parameter. The quotes are stripped before the
#       parameter value is interpreted or used.
#       See "Values with spaces, quotes, and other special characters"
#       section for more details.
#Default:
# configuration_includes_quoted_values off

#  TAG: memory_pools    on|off
#       If set, Squid will keep pools of allocated (but unused) memory
#       available for future use.  If memory is a premium on your
#       system and you believe your malloc library outperforms Squid
#       routines, disable this.
#Default:
# memory_pools on

#  TAG: memory_pools_limit      (bytes)
#       Used only with memory_pools on:
#       memory_pools_limit 50 MB
#
#       If set to a non-zero value, Squid will keep at most the specified
#       limit of allocated (but unused) memory in memory pools. All free()
#       requests that exceed this limit will be handled by your malloc
#       library. Squid does not pre-allocate any memory, just safe-keeps
#       objects that otherwise would be free()d. Thus, it is safe to set
#       memory_pools_limit to a reasonably high value even if your
#       configuration will use less memory.
#
#       If set to none, Squid will keep all memory it can. That is, there
#       will be no limit on the total amount of memory used for safe-keeping.
#
#       To disable memory allocation optimization, do not set
#       memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
#
#       An overhead for maintaining memory pools is not taken into account
#       when the limit is checked. This overhead is close to four bytes per
#       object kept. However, pools may actually _save_ memory because of
#       reduced memory thrashing in your malloc library.
#Default:
# memory_pools_limit 5 MB

#  TAG: forwarded_for   on|off|transparent|truncate|delete
#       If set to "on", Squid will append your client's IP address
#       in the HTTP requests it forwards. By default it looks like:
#
#               X-Forwarded-For: 192.1.2.3
#
#       If set to "off", it will appear as
#
#               X-Forwarded-For: unknown
#
#       If set to "transparent", Squid will not alter the
#       X-Forwarded-For header in any way.
#
#       If set to "delete", Squid will delete the entire
#       X-Forwarded-For header.
#
#       If set to "truncate", Squid will remove all existing
#       X-Forwarded-For entries, and place the client IP as the sole entry.
#Default:
# forwarded_for on

#  TAG: cachemgr_passwd
#       Specify passwords for cachemgr operations.
#
#       Usage: cachemgr_passwd password action action ...
#
#       Some valid actions are (see cache manager menu for a full list):
#               5min
#               60min
#               asndb
#               authenticator
#               cbdata
#               client_list
#               comm_incoming
#               config *
#               counters
#               delay
#               digest_stats
#               dns
#               events
#               filedescriptors
#               fqdncache
#               histograms
#               http_headers
#               info
#               io
#               ipcache
#               mem
#               menu
#               netdb
#               non_peers
#               objects
#               offline_toggle *
#               pconn
#               peer_select
#               reconfigure *
#               redirector
#               refresh
#               server_list
#               shutdown *
#               store_digest
#               storedir
#               utilization
#               via_headers
#               vm_objects
#
#       * Indicates actions which will not be performed without a
#         valid password, others can be performed if not listed here.
#
#       To disable an action, set the password to "disable".
#       To allow performing an action without a password, set the
#       password to "none".
#
#       Use the keyword "all" to set the same password for all actions.
#
#Example:
# cachemgr_passwd secret shutdown
# cachemgr_passwd lesssssssecret info stats/objects
# cachemgr_passwd disable all
#Default:
# No password. Actions which require password are denied.

#  TAG: client_db       on|off
#       If you want to disable collecting per-client statistics,
#       turn off client_db here.
#Default:
# client_db on

#  TAG: refresh_all_ims on|off
#       When you enable this option, squid will always check
#       the origin server for an update when a client sends an
#       If-Modified-Since request.  Many browsers use IMS
#       requests when the user requests a reload, and this
#       ensures those clients receive the latest version.
#
#       By default (off), squid may return a Not Modified response
#       based on the age of the cached version.
#Default:
# refresh_all_ims off

#  TAG: reload_into_ims on|off
#       When you enable this option, client no-cache or ``reload''
#       requests will be changed to If-Modified-Since requests.
#       Doing this VIOLATES the HTTP standard.  Enabling this
#       feature could make you liable for problems which it
#       causes.
#
#       see also refresh_pattern for a more selective approach.
#Default:
# reload_into_ims off

#  TAG: connect_retries
#       Limits the number of reopening attempts when establishing a single
#       TCP connection. All these attempts must still complete before the
#       applicable connection opening timeout expires.
#
#       By default and when connect_retries is set to zero, Squid does not
#       retry failed connection opening attempts.
#
#       The (not recommended) maximum is 10 tries. An attempt to configure a
#       higher value results in the value of 10 being used (with a warning).
#
#       Squid may open connections to retry various high-level forwarding
#       failures. For an outside observer, that activity may look like a
#       low-level connection reopening attempt, but those high-level retries
#       are governed by forward_max_tries instead.
#
#       See also: connect_timeout, forward_timeout, icap_connect_timeout,
#       ident_timeout, and forward_max_tries.
#Default:
# Do not retry failed connections.

#  TAG: retry_on_error
#       If set to ON Squid will automatically retry requests when
#       receiving an error response with status 403 (Forbidden),
#       500 (Internal Error), 501 or 503 (Service not available).
#       Status 502 and 504 (Gateway errors) are always retried.
#
#       This is mainly useful if you are in a complex cache hierarchy to
#       work around access control errors.
#
#       NOTE: This retry will attempt to find another working destination.
#       Which is different from the server which just failed.
#Default:
# retry_on_error off

#  TAG: as_whois_server
#       WHOIS server to query for AS numbers.  NOTE: AS numbers are
#       queried only when Squid starts up, not for every request.
#Default:
# as_whois_server whois.ra.net

#  TAG: offline_mode
#       Enable this option and Squid will never try to validate cached
#       objects.
#Default:
# offline_mode off

#  TAG: uri_whitespace
#       What to do with requests that have whitespace characters in the
#       URI.  Options:
#
#       strip:  The whitespace characters are stripped out of the URL.
#               This is the behavior recommended by RFC2396 and RFC3986
#               for tolerant handling of generic URI.
#               NOTE: This is one difference between generic URI and HTTP URLs.
#
#       deny:   The request is denied.  The user receives an "Invalid
#               Request" message.
#               This is the behaviour recommended by RFC2616 for safe
#               handling of HTTP request URL.
#
#       allow:  The request is allowed and the URI is not changed.  The
#               whitespace characters remain in the URI.  Note the
#               whitespace is passed to redirector processes if they
#               are in use.
#               Note this may be considered a violation of RFC2616
#               request parsing where whitespace is prohibited in the
#               URL field.
#
#       encode: The request is allowed and the whitespace characters are
#               encoded according to RFC1738.
#
#       chop:   The request is allowed and the URI is chopped at the
#               first whitespace.
#
#
#       NOTE the current Squid implementation of encode and chop violates
#       RFC2616 by not using a 301 redirect after altering the URL.
#Default:
# uri_whitespace strip

#  TAG: chroot
#       Specifies a directory where Squid should do a chroot() while
#       initializing.  This also causes Squid to fully drop root
#       privileges after initializing.  This means, for example, if you
#       use a HTTP port less than 1024 and try to reconfigure, you may
#       get an error saying that Squid can not open the port.
#Default:
# none

#  TAG: pipeline_prefetch
#       HTTP clients may send a pipeline of 1+N requests to Squid using a
#       single connection, without waiting for Squid to respond to the first
#       of those requests. This option limits the number of concurrent
#       requests Squid will try to handle in parallel. If set to N, Squid
#       will try to receive and process up to 1+N requests on the same
#       connection concurrently.
#
#       Defaults to 0 (off) for bandwidth management and access logging
#       reasons.
#
#       NOTE: pipelining requires persistent connections to clients.
#
#       WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
#Default:
# Do not pre-parse pipelined requests.

#  TAG: high_response_time_warning      (msec)
#       If the one-minute median response time exceeds this value,
#       Squid prints a WARNING with debug level 0 to get the
#       administrators attention.  The value is in milliseconds.
#Default:
# disabled.

#  TAG: high_page_fault_warning
#       If the one-minute average page fault rate exceeds this
#       value, Squid prints a WARNING with debug level 0 to get
#       the administrators attention.  The value is in page faults
#       per second.
#Default:
# disabled.

#  TAG: high_memory_warning
# Note: This option is only available if Squid is rebuilt with the
#       GNU Malloc with mstats()
#
#       If the memory usage (as determined by gnumalloc, if available and used)
#       exceeds this amount, Squid prints a WARNING with debug level 0 to get
#       the administrators attention.
#Default:
# disabled.

#  TAG: sleep_after_fork        (microseconds)
#       When this is set to a non-zero value, the main Squid process
#       sleeps the specified number of microseconds after a fork()
#       system call. This sleep may help the situation where your
#       system reports fork() failures due to lack of (virtual)
#       memory. Note, however, if you have a lot of child
#       processes, these sleep delays will add up and your
#       Squid will not service requests for some amount of time
#       until all the child processes have been started.
#       On Windows value less then 1000 (1 milliseconds) are
#       rounded to 1000.
#Default:
# sleep_after_fork 0

#  TAG: windows_ipaddrchangemonitor     on|off
# Note: This option is only available if Squid is rebuilt with the
#       MS Windows
#
#       On Windows Squid by default will monitor IP address changes and will 
#       reconfigure itself after any detected event. This is very useful for
#       proxies connected to internet with dial-up interfaces.
#       In some cases (a Proxy server acting as VPN gateway is one) it could be
#       desiderable to disable this behaviour setting this to 'off'.
#       Note: after changing this, Squid service must be restarted.
#Default:
# windows_ipaddrchangemonitor on

#  TAG: eui_lookup
#       Whether to lookup the EUI or MAC address of a connected client.
#Default:
# eui_lookup on

#  TAG: max_filedescriptors
#       Set the maximum number of filedescriptors, either below the
#       operating system default or up to the hard limit.
#
#       Remove from squid.conf to inherit the current ulimit soft
#       limit setting.
#
#       Note: Changing this requires a restart of Squid. Also
#       not all I/O types supports large values (eg on Windows).
#Default:
# Use operating system soft limit set by ulimit.

#  TAG: force_request_body_continuation
#       This option controls how Squid handles data upload requests from HTTP
#       and FTP agents that require a "Please Continue" control message response
#       to actually send the request body to Squid. It is mostly useful in
#       adaptation environments.
#
#       When Squid receives an HTTP request with an "Expect: 100-continue"
#       header or an FTP upload command (e.g., STOR), Squid normally sends the
#       request headers or FTP command information to an adaptation service (or
#       peer) and waits for a response. Most adaptation services (and some
#       broken peers) may not respond to Squid at that stage because they may
#       decide to wait for the HTTP request body or FTP data transfer. However,
#       that request body or data transfer may never come because Squid has not
#       responded with the HTTP 100 or FTP 150 (Please Continue) control message
#       to the request sender yet!
#
#       An allow match tells Squid to respond with the HTTP 100 or FTP 150
#       (Please Continue) control message on its own, before forwarding the
#       request to an adaptation service or peer. Such a response usually forces
#       the request sender to proceed with sending the body. A deny match tells
#       Squid to delay that control response until the origin server confirms
#       that the request body is needed. Delaying is the default behavior.
#Default:
# Deny, unless rules exist in squid.conf.

#  TAG: http_upgrade_request_protocols
#       Controls client-initiated and server-confirmed switching from HTTP to
#       another protocol (or to several protocols) using HTTP Upgrade mechanism
#       defined in RFC 7230 Section 6.7. Squid itself does not understand the
#       protocols being upgraded to and participates in the upgraded
#       communication only as a dumb TCP proxy. Admins should not allow
#       upgrading to protocols that require a more meaningful proxy
#       participation.
#
#       Usage: http_upgrade_request_protocols <protocol> allow|deny [!]acl ...
#
#       The required "protocol" parameter is either an all-caps word OTHER or an
#       explicit protocol name (e.g. "WebSocket") optionally followed by a slash
#       and a version token (e.g. "HTTP/3"). Explicit protocol names and
#       versions are case sensitive.
#
#       When an HTTP client sends an Upgrade request header, Squid iterates over
#       the client-offered protocols and, for each protocol P (with an optional
#       version V), evaluates the first non-empty set of
#       http_upgrade_request_protocols rules (if any) from the following list:
#
#               * All rules with an explicit protocol name equal to P.
#               * All rules that use OTHER instead of a protocol name.
#
#       In other words, rules using OTHER are considered for protocol P if and
#       only if there are no rules mentioning P by name.
#
#       If both of the above sets are empty, then Squid removes protocol P from
#       the Upgrade offer.
#
#       If the client sent a versioned protocol offer P/X, then explicit rules
#       referring to the same-name but different-version protocol P/Y are
#       declared inapplicable. Inapplicable rules are not evaluated (i.e. are
#       ignored). However, inapplicable rules still belong to the first set of
#       rules for P.
#
#       Within the applicable rule subset, individual rules are evaluated in
#       their configuration order. If all ACLs of an applicable "allow" rule
#       match, then the protocol offered by the client is forwarded to the next
#       hop as is. If all ACLs of an applicable "deny" rule match, then the
#       offer is dropped. If no applicable rules have matching ACLs, then the
#       offer is also dropped. The first matching rule also ends rules
#       evaluation for the offered protocol.
#
#       If all client-offered protocols are removed, then Squid forwards the
#       client request without the Upgrade header. Squid never sends an empty
#       Upgrade request header.
#
#       An Upgrade request header with a value violating HTTP syntax is dropped
#       and ignored without an attempt to use extractable individual protocol
#       offers.
#
#       Upon receiving an HTTP 101 (Switching Protocols) control message, Squid
#       checks that the server listed at least one protocol name and sent a
#       Connection:upgrade response header. Squid does not understand individual
#       protocol naming and versioning concepts enough to implement stricter
#       checks, but an admin can restrict HTTP 101 (Switching Protocols)
#       responses further using http_reply_access. Responses denied by
#       http_reply_access rules and responses flagged by the internal Upgrade
#       checks result in HTTP 502 (Bad Gateway) ERR_INVALID_RESP errors and
#       Squid-to-server connection closures.
#
#       If Squid sends an Upgrade request header, and the next hop (e.g., the
#       origin server) responds with an acceptable HTTP 101 (Switching
#       Protocols), then Squid forwards that message to the client and becomes
#       a TCP tunnel.
#
#       The presence of an Upgrade request header alone does not preclude cache
#       lookups. In other words, an Upgrade request might be satisfied from the
#       cache, using regular HTTP caching rules.
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#
#       Each of the following groups of configuration lines represents a
#       separate configuration example:
#
#       # never upgrade to protocol Foo; all others are OK
#       http_upgrade_request_protocols Foo deny all
#       http_upgrade_request_protocols OTHER allow all
#
#       # only allow upgrades to protocol Bar (except for its first version)
#       http_upgrade_request_protocols Bar/1 deny all
#       http_upgrade_request_protocols Bar allow all
#       http_upgrade_request_protocols OTHER deny all # this rule is optional
#
#       # only allow upgrades to protocol Baz, and only if Baz is the only offer
#       acl UpgradeHeaderHasMultipleOffers ...
#       http_upgrade_request_protocols Baz deny UpgradeHeaderHasMultipleOffers
#       http_upgrade_request_protocols Baz allow all
#Default:
# Upgrade header dropped, effectively blocking an upgrade attempt.

#  TAG: server_pconn_for_nonretriable
#       This option provides fine-grained control over persistent connection
#       reuse when forwarding HTTP requests that Squid cannot retry. It is useful
#       in environments where opening new connections is very expensive
#       (e.g., all connections are secured with TLS with complex client and server
#       certificate validation) and race conditions associated with persistent
#       connections are very rare and/or only cause minor problems.
#
#       HTTP prohibits retrying unsafe and non-idempotent requests (e.g., POST).
#       Squid limitations also prohibit retrying all requests with bodies (e.g., PUT).
#       By default, when forwarding such "risky" requests, Squid opens a new
#       connection to the server or cache_peer, even if there is an idle persistent
#       connection available. When Squid is configured to risk sending a non-retriable
#       request on a previously used persistent connection, and the server closes
#       the connection before seeing that risky request, the user gets an error response
#       from Squid. In most cases, that error response will be HTTP 502 (Bad Gateway)
#       with ERR_ZERO_SIZE_OBJECT or ERR_WRITE_ERROR (peer connection reset) error detail.
#
#       If an allow rule matches, Squid reuses an available idle persistent connection
#       (if any) for the request that Squid cannot retry. If a deny rule matches, then
#       Squid opens a new connection for the request that Squid cannot retry.
#
#       This option does not affect requests that Squid can retry. They will reuse idle
#       persistent connections (if any).
#
#       This clause only supports fast acl types.
#       See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
#
#       Example:
#               acl SpeedIsWorthTheRisk method POST
#               server_pconn_for_nonretriable allow SpeedIsWorthTheRisk
#Default:
# Open new connections for forwarding requests Squid cannot retry safely.

#  TAG: happy_eyeballs_connect_timeout  (msec)
#       This Happy Eyeballs (RFC 8305) tuning directive specifies the minimum
#       delay between opening a primary to-server connection and opening a
#       spare to-server connection for the same master transaction. This delay
#       is similar to the Connection Attempt Delay in RFC 8305, but it is only
#       applied to the first spare connection attempt. Subsequent spare
#       connection attempts use happy_eyeballs_connect_gap, and primary
#       connection attempts are not artificially delayed at all.
#
#       Terminology: The "primary" and "spare" designations are determined by
#       the order of DNS answers received by Squid: If Squid DNS AAAA query
#       was answered first, then primary connections are connections to IPv6
#       peer addresses (while spare connections use IPv4 addresses).
#       Similarly, if Squid DNS A query was answered first, then primary
#       connections are connections to IPv4 peer addresses (while spare
#       connections use IPv6 addresses).
#
#       Shorter happy_eyeballs_connect_timeout values reduce master
#       transaction response time, potentially improving user-perceived
#       response times (i.e., making user eyeballs happier). Longer delays
#       reduce both concurrent connection level and server bombardment with
#       connection requests, potentially improving overall Squid performance
#       and reducing the chance of being blocked by servers for opening too
#       many unused connections.
#
#       RFC 8305 prohibits happy_eyeballs_connect_timeout values smaller than
#       10 (milliseconds) to "avoid congestion collapse in the presence of
#       high packet-loss rates".
#
#       The following Happy Eyeballs directives place additional connection
#       opening restrictions: happy_eyeballs_connect_gap and
#       happy_eyeballs_connect_limit.
#Default:
# happy_eyeballs_connect_timeout 250

#  TAG: happy_eyeballs_connect_gap      (msec)
#       This Happy Eyeballs (RFC 8305) tuning directive specifies the
#       minimum delay between opening spare to-server connections (to any
#       server; i.e. across all concurrent master transactions in a Squid
#       instance). Each SMP worker currently multiplies the configured gap
#       by the total number of workers so that the combined spare connection
#       opening rate of a Squid instance obeys the configured limit. The
#       workers do not coordinate connection openings yet; a micro burst
#       of spare connection openings may violate the configured gap.
#
#       This directive has similar trade-offs as
#       happy_eyeballs_connect_timeout, but its focus is on limiting traffic
#       amplification effects for Squid as a whole, while
#       happy_eyeballs_connect_timeout works on an individual master
#       transaction level.
#
#       The following Happy Eyeballs directives place additional connection
#       opening restrictions: happy_eyeballs_connect_timeout and
#       happy_eyeballs_connect_limit. See the former for related terminology.
#Default:
# no artificial delays between spare attempts

#  TAG: happy_eyeballs_connect_limit
#       This Happy Eyeballs (RFC 8305) tuning directive specifies the
#       maximum number of spare to-server connections (to any server; i.e.
#       across all concurrent master transactions in a Squid instance).
#       Each SMP worker gets an equal share of the total limit. However,
#       the workers do not share the actual connection counts yet, so one
#       (busier) worker cannot "borrow" spare connection slots from another
#       (less loaded) worker.
#
#       Setting this limit to zero disables concurrent use of primary and
#       spare TCP connections: Spare connection attempts are made only after
#       all primary attempts fail. However, Squid would still use the
#       DNS-related optimizations of the Happy Eyeballs approach.
#
#       This directive has similar trade-offs as happy_eyeballs_connect_gap,
#       but its focus is on limiting Squid overheads, while
#       happy_eyeballs_connect_gap focuses on the origin server and peer
#       overheads.
#
#       The following Happy Eyeballs directives place additional connection
#       opening restrictions: happy_eyeballs_connect_timeout and
#       happy_eyeballs_connect_gap. See the former for related terminology.
#Default:
# no artificial limit on the number of concurrent spare attempts