1 ## Copyright (C) 1996-2015 The Squid Software Foundation and contributors
3 ## Squid software is distributed under GPLv2+ license and includes
4 ## contributions from numerous individuals and organizations.
5 ## Please see the COPYING and CONTRIBUTORS files for details.
10 ----------------------------
12 This is the documentation for the Squid configuration file.
13 This documentation can also be found online at:
14 http://www.squid-cache.org/Doc/config/
16 You may wish to look at the Squid home page and wiki for the
17 FAQ and other documentation:
18 http://www.squid-cache.org/
19 http://wiki.squid-cache.org/SquidFaq
20 http://wiki.squid-cache.org/ConfigExamples
22 This documentation shows what the defaults for various directives
23 happen to be. If you don't need to change the default, you should
24 leave the line out of your squid.conf in most cases.
26 In some cases "none" refers to no default setting at all,
27 while in other cases it refers to the value of the option
28 - the comments for that keyword indicate if this is the case.
33 Configuration options can be included using the "include" directive.
34 Include takes a list of files to include. Quoting and wildcards are
39 include /path/to/included/file/squid.acl.config
41 Includes can be nested up to a hard-coded depth of 16 levels.
42 This arbitrary restriction is to prevent recursive include references
43 from causing Squid entering an infinite loop whilst trying to load
46 Values with byte units
48 Squid accepts size units on some size related directives. All
49 such directives are documented with a default value displaying
52 Units accepted by Squid are:
54 KB - Kilobyte (1024 bytes)
58 Values with spaces, quotes, and other special characters
60 Squid supports directive parameters with spaces, quotes, and other
61 special characters. Surround such parameters with "double quotes". Use
62 the configuration_includes_quoted_values directive to enable or
65 Squid supports reading configuration option parameters from external
66 files using the syntax:
67 parameters("/path/filename")
69 acl whitelist dstdomain parameters("/etc/squid/whitelist.txt")
71 Conditional configuration
73 If-statements can be used to make configuration directives
77 ... regular configuration directives ...
79 ... regular configuration directives ...]
82 The else part is optional. The keywords "if", "else", and "endif"
83 must be typed on their own lines, as if they were regular
84 configuration directives.
86 NOTE: An else-if condition is not supported.
88 These individual conditions types are supported:
91 Always evaluates to true.
93 Always evaluates to false.
95 Equality comparison of two integer numbers.
100 The following SMP-related preprocessor macros can be used.
102 ${process_name} expands to the current Squid process "name"
103 (e.g., squid1, squid2, or cache1).
105 ${process_number} expands to the current Squid process
106 identifier, which is an integer number (e.g., 1, 2, 3) unique
107 across all Squid processes of the current service instance.
109 ${service_name} expands into the current Squid service instance
110 name identifier which is provided by -n on the command line.
114 # options still not yet ported from 2.7 to 3.x
115 NAME: broken_vary_encoding
118 This option is not yet supported by Squid-3.
124 This option is not yet supported by Squid-3.
130 This option is not yet supported by Squid-3.
133 NAME: external_refresh_check
136 This option is not yet supported by Squid-3.
139 NAME: location_rewrite_program location_rewrite_access location_rewrite_children location_rewrite_concurrency
142 This option is not yet supported by Squid-3.
145 NAME: refresh_stale_hit
148 This option is not yet supported by Squid-3.
151 # Options removed in 3.6
152 NAME: cache_peer_domain cache_host_domain
155 Replace with dstdomain ACLs and cache_peer_access.
158 NAME: sslproxy_cafile
161 Remove this line. Use tls_outgoing_options cafile= instead.
164 NAME: sslproxy_capath
167 Remove this line. Use tls_outgoing_options capath= instead.
170 NAME: sslproxy_cipher
173 Remove this line. Use tls_outgoing_options cipher= instead.
176 NAME: sslproxy_client_certificate
179 Remove this line. Use tls_outgoing_options cert= instead.
182 NAME: sslproxy_client_key
185 Remove this line. Use tls_outgoing_options key= instead.
191 Remove this line. Use tls_outgoing_options flags= instead.
194 NAME: sslproxy_options
197 Remove this line. Use tls_outgoing_options options= instead.
200 NAME: sslproxy_version
203 Remove this line. Use tls_outgoing_options options= instead.
206 # Options removed in 3.5
207 NAME: hierarchy_stoplist
210 Remove this line. Use always_direct or cache_peer_access ACLs instead if you need to prevent cache_peer use.
213 # Options removed in 3.4
217 Remove this line. Use acls with access_log directives to control access logging
223 Remove this line. Use acls with icap_log directives to control icap logging
226 # Options Removed in 3.3
227 NAME: ignore_ims_on_miss
230 Remove this line. The HTTP/1.1 feature is now configured by 'cache_miss_revalidate'.
233 # Options Removed in 3.2
234 NAME: chunked_request_body_max_size
237 Remove this line. Squid is now HTTP/1.1 compliant.
240 NAME: dns_v4_fallback
243 Remove this line. Squid performs a 'Happy Eyeballs' algorithm, the 'fallback' algorithm is no longer relevant.
246 NAME: emulate_httpd_log
249 Replace this with an access_log directive using the format 'common' or 'combined'.
255 Use a regular access.log with ACL limiting it to MISS events.
261 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
264 NAME: ignore_expect_100
267 Remove this line. The HTTP/1.1 feature is now fully supported by default.
273 Remove this option from your config. To log FQDN use %>A in the log format.
276 NAME: log_ip_on_direct
279 Remove this option from your config. To log server or peer names use %<A in the log format.
282 NAME: maximum_single_addr_tries
285 Replaced by connect_retries. The behaviour has changed, please read the documentation before altering.
288 NAME: referer_log referrer_log
291 Replace this with an access_log directive using the format 'referrer'.
297 Remove this line. The feature is supported by default in storage types where update is implemented.
300 NAME: url_rewrite_concurrency
303 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
309 Replace this with an access_log directive using the format 'useragent'.
312 # Options Removed in 3.1
316 Remove this line. DNS is no longer tested on startup.
319 NAME: extension_methods
322 Remove this line. All valid methods for HTTP are accepted by default.
325 # 2.7 Options Removed/Replaced in 3.2
330 # 2.7 Options Removed/Replaced in 3.1
338 Remove this line. HTTP/1.1 is supported by default.
341 NAME: upgrade_http0.9
344 Remove this line. ICY/1.0 streaming protocol is supported by default.
347 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
350 Alter these entries. Use the qos_flows directive instead.
353 # Options Removed in 3.0
357 Since squid-3.0 replace with request_header_access or reply_header_access
358 depending on whether you wish to match client requests or server replies.
361 NAME: httpd_accel_no_pmtu_disc
364 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
367 NAME: wais_relay_host
370 Replace this line with 'cache_peer' configuration.
373 NAME: wais_relay_port
376 Replace this line with 'cache_peer' configuration.
381 -----------------------------------------------------------------------------
388 DEFAULT_DOC: SMP support disabled.
390 Number of main Squid processes or "workers" to fork and maintain.
391 0: "no daemon" mode, like running "squid -N ..."
392 1: "no SMP" mode, start one main Squid process daemon (default)
393 N: start N main Squid process daemons (i.e., SMP mode)
395 In SMP mode, each worker does nearly all what a single Squid daemon
396 does (e.g., listen on http_port and forward HTTP requests).
399 NAME: cpu_affinity_map
401 LOC: Config.cpuAffinityMap
403 DEFAULT_DOC: Let operating system decide.
405 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
407 Sets 1:1 mapping between Squid processes and CPU cores. For example,
409 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
411 affects processes 1 through 4 only and places them on the first
412 four even cores, starting with core #1.
414 CPU cores are numbered starting from 1. Requires support for
415 sched_getaffinity(2) and sched_setaffinity(2) system calls.
417 Multiple cpu_affinity_map options are merged.
423 OPTIONS FOR AUTHENTICATION
424 -----------------------------------------------------------------------------
433 This is used to define parameters for the various authentication
434 schemes supported by Squid.
436 format: auth_param scheme parameter [setting]
438 The order in which authentication schemes are presented to the client is
439 dependent on the order the scheme first appears in config file. IE
440 has a bug (it's not RFC 2617 compliant) in that it will use the basic
441 scheme if basic is the first entry presented, even if more secure
442 schemes are presented. For now use the order in the recommended
443 settings section below. If other browsers have difficulties (don't
444 recognize the schemes offered even if you are using basic) either
445 put basic first, or disable the other schemes (by commenting out their
448 Once an authentication scheme is fully configured, it can only be
449 shutdown by shutting squid down and restarting. Changes can be made on
450 the fly and activated with a reconfigure. I.E. You can change to a
451 different helper, but not unconfigure the helper completely.
453 Please note that while this directive defines how Squid processes
454 authentication it does not automatically activate authentication.
455 To use authentication you must in addition make use of ACLs based
456 on login name in http_access (proxy_auth, proxy_auth_regex or
457 external with %LOGIN used in the format tag). The browser will be
458 challenged for authentication on the first such acl encountered
459 in http_access processing and will also be re-challenged for new
460 login credentials if the request is being denied by a proxy_auth
463 WARNING: authentication can't be used in a transparently intercepting
464 proxy as the client then thinks it is talking to an origin server and
465 not the proxy. This is a limitation of bending the TCP/IP protocol to
466 transparently intercepting port 80, not a limitation in Squid.
467 Ports flagged 'transparent', 'intercept', or 'tproxy' have
468 authentication disabled.
470 === Parameters common to all schemes. ===
473 Specifies the command for the external authenticator.
475 By default, each authentication scheme is not used unless a
476 program is specified.
478 See http://wiki.squid-cache.org/Features/AddonHelpers for
479 more details on helper operations and creating your own.
482 Specifies a string to be append to request line format for
483 the authentication helper. "Quoted" format values may contain
484 spaces and logformat %macros. In theory, any logformat %macro
485 can be used. In practice, a %macro expands as a dash (-) if
486 the helper request is sent before the required macro
487 information is available to Squid.
489 By default, Squid uses request formats provided in
490 scheme-specific examples below (search for %credentials).
492 The expanded key_extras value is added to the Squid credentials
493 cache and, hence, will affect authentication. It can be used to
494 autenticate different users with identical user names (e.g.,
495 when user authentication depends on http_port).
497 Avoid adding frequently changing information to key_extras. For
498 example, if you add user source IP, and it changes frequently
499 in your environment, then max_user_ip ACL is going to treat
500 every user+IP combination as a unique "user", breaking the ACL
501 and wasting a lot of memory on those user records. It will also
502 force users to authenticate from scratch whenever their IP
506 Specifies the protection scope (aka realm name) which is to be
507 reported to the client for the authentication scheme. It is
508 commonly part of the text the user will see when prompted for
509 their username and password.
511 For Basic the default is "Squid proxy-caching web server".
512 For Digest there is no default, this parameter is mandatory.
513 For NTLM and Negotiate this parameter is ignored.
515 "children" numberofchildren [startup=N] [idle=N] [concurrency=N] [queue-size=N]
517 The maximum number of authenticator processes to spawn. If
518 you start too few Squid will have to wait for them to process
519 a backlog of credential verifications, slowing it down. When
520 password verifications are done via a (slow) network you are
521 likely to need lots of authenticator processes.
523 The startup= and idle= options permit some skew in the exact
524 amount run. A minimum of startup=N will begin during startup
525 and reconfigure. Squid will start more in groups of up to
526 idle=N in an attempt to meet traffic needs and to keep idle=N
527 free above those traffic needs up to the maximum.
529 The concurrency= option sets the number of concurrent requests
530 the helper can process. The default of 0 is used for helpers
531 who only supports one request at a time. Setting this to a
532 number greater than 0 changes the protocol used to include a
533 channel ID field first on the request/response line, allowing
534 multiple requests to be sent to the same helper in parallel
535 without waiting for the response.
537 Concurrency must not be set unless it's known the helper
538 supports the input format with channel-ID fields.
540 The queue-size= option sets the maximum number of queued
541 requests. If the queued requests exceed queue size for more
542 than 3 minutes then squid aborts its operation.
543 The default value is set to 2*numberofchildren/
545 NOTE: NTLM and Negotiate schemes do not support concurrency
546 in the Squid code module even though some helpers can.
549 IF HAVE_AUTH_MODULE_BASIC
550 === Basic authentication parameters ===
553 HTTP uses iso-latin-1 as character set, while some
554 authentication backends such as LDAP expects UTF-8. If this is
555 set to on Squid will translate the HTTP iso-latin-1 charset to
556 UTF-8 before sending the username and password to the helper.
558 "credentialsttl" timetolive
559 Specifies how long squid assumes an externally validated
560 username:password pair is valid for - in other words how
561 often the helper program is called for that user. Set this
562 low to force revalidation with short lived passwords.
564 NOTE: setting this high does not impact your susceptibility
565 to replay attacks unless you are using an one-time password
566 system (such as SecureID). If you are using such a system,
567 you will be vulnerable to replay attacks unless you also
568 use the max_user_ip ACL in an http_access rule.
570 "casesensitive" on|off
571 Specifies if usernames are case sensitive. Most user databases
572 are case insensitive allowing the same username to be spelled
573 using both lower and upper case letters, but some are case
574 sensitive. This makes a big difference for user_max_ip ACL
575 processing and similar.
578 IF HAVE_AUTH_MODULE_DIGEST
579 === Digest authentication parameters ===
582 HTTP uses iso-latin-1 as character set, while some
583 authentication backends such as LDAP expects UTF-8. If this is
584 set to on Squid will translate the HTTP iso-latin-1 charset to
585 UTF-8 before sending the username and password to the helper.
587 "nonce_garbage_interval" timeinterval
588 Specifies the interval that nonces that have been issued
589 to client_agent's are checked for validity.
591 "nonce_max_duration" timeinterval
592 Specifies the maximum length of time a given nonce will be
595 "nonce_max_count" number
596 Specifies the maximum number of times a given nonce can be
599 "nonce_strictness" on|off
600 Determines if squid requires strict increment-by-1 behavior
601 for nonce counts, or just incrementing (off - for use when
602 user agents generate nonce counts that occasionally miss 1
603 (ie, 1,2,4,6)). Default off.
605 "check_nonce_count" on|off
606 This directive if set to off can disable the nonce count check
607 completely to work around buggy digest qop implementations in
608 certain mainstream browser versions. Default on to check the
609 nonce count to protect from authentication replay attacks.
611 "post_workaround" on|off
612 This is a workaround to certain buggy browsers who send an
613 incorrect request digest in POST requests when reusing the
614 same nonce as acquired earlier on a GET request.
617 IF HAVE_AUTH_MODULE_NEGOTIATE
618 === Negotiate authentication parameters ===
621 If you experience problems with PUT/POST requests when using
622 the this authentication scheme then you can try setting this
623 to off. This will cause Squid to forcibly close the connection
624 on the initial request where the browser asks which schemes
625 are supported by the proxy.
628 IF HAVE_AUTH_MODULE_NTLM
629 === NTLM authentication parameters ===
632 If you experience problems with PUT/POST requests when using
633 the this authentication scheme then you can try setting this
634 to off. This will cause Squid to forcibly close the connection
635 on the initial request where the browser asks which schemes
636 are supported by the proxy.
639 === Example Configuration ===
641 This configuration displays the recommended authentication scheme
642 order from most to least secure with recommended minimum configuration
643 settings for each scheme:
645 #auth_param negotiate program <uncomment and complete this line to activate>
646 #auth_param negotiate children 20 startup=0 idle=1
647 #auth_param negotiate keep_alive on
649 #auth_param digest program <uncomment and complete this line to activate>
650 #auth_param digest children 20 startup=0 idle=1
651 #auth_param digest realm Squid proxy-caching web server
652 #auth_param digest nonce_garbage_interval 5 minutes
653 #auth_param digest nonce_max_duration 30 minutes
654 #auth_param digest nonce_max_count 50
656 #auth_param ntlm program <uncomment and complete this line to activate>
657 #auth_param ntlm children 20 startup=0 idle=1
658 #auth_param ntlm keep_alive on
660 #auth_param basic program <uncomment and complete this line>
661 #auth_param basic children 5 startup=5 idle=1
662 #auth_param basic realm Squid proxy-caching web server
663 #auth_param basic credentialsttl 2 hours
666 NAME: authenticate_cache_garbage_interval
669 LOC: Config.authenticateGCInterval
671 The time period between garbage collection across the username cache.
672 This is a trade-off between memory utilization (long intervals - say
673 2 days) and CPU (short intervals - say 1 minute). Only change if you
677 NAME: authenticate_ttl
680 LOC: Config.authenticateTTL
682 The time a user & their credentials stay in the logged in
683 user cache since their last request. When the garbage
684 interval passes, all user credentials that have passed their
685 TTL are removed from memory.
688 NAME: authenticate_ip_ttl
690 LOC: Config.authenticateIpTTL
693 If you use proxy authentication and the 'max_user_ip' ACL,
694 this directive controls how long Squid remembers the IP
695 addresses associated with each user. Use a small value
696 (e.g., 60 seconds) if your users might change addresses
697 quickly, as is the case with dialup. You might be safe
698 using a larger value (e.g., 2 hours) in a corporate LAN
699 environment with relatively static address assignments.
704 -----------------------------------------------------------------------------
707 NAME: external_acl_type
708 TYPE: externalAclHelper
709 LOC: Config.externalAclHelperList
712 This option defines external acl classes using a helper program
713 to look up the status
715 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
719 ttl=n TTL in seconds for cached results (defaults to 3600
723 TTL for cached negative lookups (default same
726 grace=n Percentage remaining of TTL where a refresh of a
727 cached entry should be initiated without needing to
728 wait for a new reply. (default is for no grace period)
730 cache=n Limit the result cache size, default is 262144.
731 The expanded FORMAT value is used as the cache key, so
732 if the details in FORMAT are highly variable a larger
733 cache may be needed to produce reduction in helper load.
736 Maximum number of acl helper processes spawned to service
737 external acl lookups of this type. (default 20)
740 Minimum number of acl helper processes to spawn during
741 startup and reconfigure to service external acl lookups
742 of this type. (default 0)
745 Number of acl helper processes to keep ahead of traffic
746 loads. Squid will spawn this many at once whenever load
747 rises above the capabilities of existing processes.
748 Up to the value of children-max. (default 1)
750 concurrency=n concurrency level per process. Only used with helpers
751 capable of processing more than one query at a time.
753 queue-size=N The queue-size= option sets the maximum number of queued
754 requests. If the queued requests exceed queue size
756 The default value is set to 2*children-max.
758 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers.
760 ipv4 / ipv6 IP protocol used to communicate with this helper.
761 The default is to auto-detect IPv6 and use it when available.
764 FORMAT is a series of %macro codes. See logformat directive for a full list
765 of the accepted codes. Although note that at the time of any external ACL
766 being tested data may not be available and thus some %macro expand to '-'.
768 In addition to the logformat codes; when processing external ACLs these
769 additional macros are made available:
771 %ACL The name of the ACL being tested.
773 %DATA The ACL arguments. If a logformat encoding modifier
774 is used it will encode the whole set of arguments
777 If not used; then any arguments are automatically
778 added at the end of the line sent to the helper
779 as separately URL-encoded fields.
781 If SSL is enabled, the following formating codes become available:
783 %USER_CERT SSL User certificate in PEM format
784 %USER_CERTCHAIN SSL User certificate chain in PEM format
785 %USER_CERT_xx SSL User certificate subject attribute xx
786 %USER_CA_CERT_xx SSL User certificate issuer attribute xx
789 NOTE: all other format codes accepted by older Squid versions
793 General request syntax:
795 [channel-ID] FORMAT-values [acl-values ...]
798 FORMAT-values consists of transaction details expanded with
799 whitespace separation per the config file FORMAT specification
800 using the FORMAT macros listed above.
802 acl-values consists of any string specified in the referencing
803 config 'acl ... external' line. see the "acl external" directive.
805 Request values sent to the helper are URL escaped to protect
806 each value in requests against whitespaces.
808 If using protocol=2.5 then the request sent to the helper is not
809 URL escaped to protect against whitespace.
811 NOTE: protocol=3.0 is deprecated as no longer necessary.
813 When using the concurrency= option the protocol is changed by
814 introducing a query channel tag in front of the request/response.
815 The query channel tag is a number between 0 and concurrency-1.
816 This value must be echoed back unchanged to Squid as the first part
817 of the response relating to its request.
820 The helper receives lines expanded per the above format specification
821 and for each input line returns 1 line starting with OK/ERR/BH result
822 code and optionally followed by additional keywords with more details.
825 General result syntax:
827 [channel-ID] result keyword=value ...
829 Result consists of one of the codes:
832 the ACL test produced a match.
835 the ACL test does not produce a match.
838 An internal error occurred in the helper, preventing
839 a result being identified.
841 The meaning of 'a match' is determined by your squid.conf
842 access control configuration. See the Squid wiki for details.
846 user= The users name (login)
848 password= The users password (for login= cache_peer option)
850 message= Message describing the reason for this response.
851 Available as %o in error pages.
852 Useful on (ERR and BH results).
854 tag= Apply a tag to a request. Only sets a tag once,
855 does not alter existing tags.
857 log= String to be logged in access.log. Available as
858 %ea in logformat specifications.
860 clt_conn_tag= Associates a TAG with the client TCP connection.
861 Please see url_rewrite_program related documentation
864 Any keywords may be sent on any response whether OK, ERR or BH.
866 All response keyword values need to be a single token with URL
867 escaping, or enclosed in double quotes (") and escaped using \ on
868 any double quotes or \ characters within the value. The wrapping
869 double quotes are removed before the value is interpreted by Squid.
870 \r and \n are also replace by CR and LF.
872 Some example key values:
876 user="J. \"Bob\" Smith"
883 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
884 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
885 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
886 DEFAULT: ssl::certUntrusted ssl_error X509_V_ERR_INVALID_CA X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY X509_V_ERR_CERT_UNTRUSTED
887 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
890 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
891 DEFAULT: localhost src 127.0.0.1/32 ::1
892 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
893 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
895 Defining an Access List
897 Every access list definition must begin with an aclname and acltype,
898 followed by either type-specific arguments or a quoted filename that
901 acl aclname acltype argument ...
902 acl aclname acltype "file" ...
904 When using "file", the file should contain one item per line.
906 Some acl types supports options which changes their default behaviour.
907 The available options are:
909 -i,+i By default, regular expressions are CASE-SENSITIVE. To make them
910 case-insensitive, use the -i option. To return case-sensitive
911 use the +i option between patterns, or make a new ACL line
914 -n Disable lookups and address type conversions. If lookup or
915 conversion is required because the parameter type (IP or
916 domain name) does not match the message address type (domain
917 name or IP), then the ACL would immediately declare a mismatch
918 without any warnings or lookups.
920 -- Used to stop processing all options, in the case the first acl
921 value has '-' character as first character (for example the '-'
922 is a valid domain name)
924 Some acl types require suspending the current request in order
925 to access some external data source.
926 Those which do are marked with the tag [slow], those which
927 don't are marked as [fast].
928 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
929 for further information
931 ***** ACL TYPES AVAILABLE *****
933 acl aclname src ip-address/mask ... # clients IP address [fast]
934 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
935 acl aclname dst [-n] ip-address/mask ... # URL host's IP address [slow]
936 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
938 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
940 # The 'arp' ACL code is not portable to all operating systems.
941 # It works on Linux, Solaris, Windows, FreeBSD, and some other
944 # NOTE: Squid can only determine the MAC/EUI address for IPv4
945 # clients that are on the same subnet. If the client is on a
946 # different subnet, then Squid cannot find out its address.
948 # NOTE 2: IPv6 protocol does not contain ARP. MAC/EUI is either
949 # encoded directly in the IPv6 address or not available.
951 acl aclname srcdomain .foo.com ...
952 # reverse lookup, from client IP [slow]
953 acl aclname dstdomain [-n] .foo.com ...
954 # Destination server from URL [fast]
955 acl aclname srcdom_regex [-i] \.foo\.com ...
956 # regex matching client name [slow]
957 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
958 # regex matching server [fast]
960 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
961 # based URL is used and no match is found. The name "none" is used
962 # if the reverse lookup fails.
964 acl aclname src_as number ...
965 acl aclname dst_as number ...
967 # Except for access control, AS numbers can be used for
968 # routing of requests to specific caches. Here's an
969 # example for routing all requests for AS#1241 and only
970 # those to mycache.mydomain.net:
971 # acl asexample dst_as 1241
972 # cache_peer_access mycache.mydomain.net allow asexample
973 # cache_peer_access mycache_mydomain.net deny all
975 acl aclname peername myPeer ...
977 # match against a named cache_peer entry
978 # set unique name= on cache_peer lines for reliable use.
980 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
990 # h1:m1 must be less than h2:m2
992 acl aclname url_regex [-i] ^http:// ...
993 # regex matching on whole URL [fast]
994 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
995 # regex matching on URL login field
996 acl aclname urlpath_regex [-i] \.gif$ ...
997 # regex matching on URL path [fast]
999 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
1001 acl aclname localport 3128 ... # TCP port the client connected to [fast]
1002 # NP: for interception mode this is usually '80'
1004 acl aclname myportname 3128 ... # *_port name [fast]
1006 acl aclname proto HTTP FTP ... # request protocol [fast]
1008 acl aclname method GET POST ... # HTTP request method [fast]
1010 acl aclname http_status 200 301 500- 400-403 ...
1011 # status code in reply [fast]
1013 acl aclname browser [-i] regexp ...
1014 # pattern match on User-Agent header (see also req_header below) [fast]
1016 acl aclname referer_regex [-i] regexp ...
1017 # pattern match on Referer header [fast]
1018 # Referer is highly unreliable, so use with care
1020 acl aclname ident username ...
1021 acl aclname ident_regex [-i] pattern ...
1022 # string match on ident output [slow]
1023 # use REQUIRED to accept any non-null ident.
1025 acl aclname proxy_auth [-i] username ...
1026 acl aclname proxy_auth_regex [-i] pattern ...
1027 # perform http authentication challenge to the client and match against
1028 # supplied credentials [slow]
1030 # takes a list of allowed usernames.
1031 # use REQUIRED to accept any valid username.
1033 # Will use proxy authentication in forward-proxy scenarios, and plain
1034 # http authenticaiton in reverse-proxy scenarios
1036 # NOTE: when a Proxy-Authentication header is sent but it is not
1037 # needed during ACL checking the username is NOT logged
1040 # NOTE: proxy_auth requires a EXTERNAL authentication program
1041 # to check username/password combinations (see
1042 # auth_param directive).
1044 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
1045 # as the browser needs to be configured for using a proxy in order
1046 # to respond to proxy authentication.
1048 acl aclname snmp_community string ...
1049 # A community string to limit access to your SNMP Agent [fast]
1052 # acl snmppublic snmp_community public
1054 acl aclname maxconn number
1055 # This will be matched when the client's IP address has
1056 # more than <number> TCP connections established. [fast]
1057 # NOTE: This only measures direct TCP links so X-Forwarded-For
1058 # indirect clients are not counted.
1060 acl aclname max_user_ip [-s] number
1061 # This will be matched when the user attempts to log in from more
1062 # than <number> different ip addresses. The authenticate_ip_ttl
1063 # parameter controls the timeout on the ip entries. [fast]
1064 # If -s is specified the limit is strict, denying browsing
1065 # from any further IP addresses until the ttl has expired. Without
1066 # -s Squid will just annoy the user by "randomly" denying requests.
1067 # (the counter is reset each time the limit is reached and a
1068 # request is denied)
1069 # NOTE: in acceleration mode or where there is mesh of child proxies,
1070 # clients may appear to come from multiple addresses if they are
1071 # going through proxy farms, so a limit of 1 may cause user problems.
1073 acl aclname random probability
1074 # Pseudo-randomly match requests. Based on the probability given.
1075 # Probability may be written as a decimal (0.333), fraction (1/3)
1076 # or ratio of matches:non-matches (3:5).
1078 acl aclname req_mime_type [-i] mime-type ...
1079 # regex match against the mime type of the request generated
1080 # by the client. Can be used to detect file upload or some
1081 # types HTTP tunneling requests [fast]
1082 # NOTE: This does NOT match the reply. You cannot use this
1083 # to match the returned file type.
1085 acl aclname req_header header-name [-i] any\.regex\.here
1086 # regex match against any of the known request headers. May be
1087 # thought of as a superset of "browser", "referer" and "mime-type"
1090 acl aclname rep_mime_type [-i] mime-type ...
1091 # regex match against the mime type of the reply received by
1092 # squid. Can be used to detect file download or some
1093 # types HTTP tunneling requests. [fast]
1094 # NOTE: This has no effect in http_access rules. It only has
1095 # effect in rules that affect the reply data stream such as
1096 # http_reply_access.
1098 acl aclname rep_header header-name [-i] any\.regex\.here
1099 # regex match against any of the known reply headers. May be
1100 # thought of as a superset of "browser", "referer" and "mime-type"
1103 acl aclname external class_name [arguments...]
1104 # external ACL lookup via a helper class defined by the
1105 # external_acl_type directive [slow]
1107 acl aclname user_cert attribute values...
1108 # match against attributes in a user SSL certificate
1109 # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
1111 acl aclname ca_cert attribute values...
1112 # match against attributes a users issuing CA SSL certificate
1113 # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
1115 acl aclname ext_user username ...
1116 acl aclname ext_user_regex [-i] pattern ...
1117 # string match on username returned by external acl helper [slow]
1118 # use REQUIRED to accept any non-null user name.
1120 acl aclname tag tagvalue ...
1121 # string match on tag returned by external acl helper [fast]
1122 # DEPRECATED. Only the first tag will match with this ACL.
1123 # Use the 'note' ACL instead for handling multiple tag values.
1125 acl aclname hier_code codename ...
1126 # string match against squid hierarchy code(s); [fast]
1127 # e.g., DIRECT, PARENT_HIT, NONE, etc.
1129 # NOTE: This has no effect in http_access rules. It only has
1130 # effect in rules that affect the reply data stream such as
1131 # http_reply_access.
1133 acl aclname note name [value ...]
1134 # match transaction annotation [fast]
1135 # Without values, matches any annotation with a given name.
1136 # With value(s), matches any annotation with a given name that
1137 # also has one of the given values.
1138 # Names and values are compared using a string equality test.
1139 # Annotation sources include note and adaptation_meta directives
1140 # as well as helper and eCAP responses.
1142 acl aclname adaptation_service service ...
1143 # Matches the name of any icap_service, ecap_service,
1144 # adaptation_service_set, or adaptation_service_chain that Squid
1145 # has used (or attempted to use) for the master transaction.
1146 # This ACL must be defined after the corresponding adaptation
1147 # service is named in squid.conf. This ACL is usable with
1148 # adaptation_meta because it starts matching immediately after
1149 # the service has been selected for adaptation.
1152 acl aclname ssl_error errorname
1153 # match against SSL certificate validation error [fast]
1155 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1158 # The following can be used as shortcuts for certificate properties:
1159 # [ssl::]certHasExpired: the "not after" field is in the past
1160 # [ssl::]certNotYetValid: the "not before" field is in the future
1161 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1162 # [ssl::]certSelfSigned: The certificate is self signed.
1163 # [ssl::]certDomainMismatch: The certificate CN domain does not
1164 # match the name the name of the host we are connecting to.
1166 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1167 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1168 # predefined ACLs, just like the 'all' ACL.
1170 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1171 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1173 acl aclname server_cert_fingerprint [-sha1] fingerprint
1174 # match against server SSL certificate fingerprint [fast]
1176 # The fingerprint is the digest of the DER encoded version
1177 # of the whole certificate. The user should use the form: XX:XX:...
1178 # Optional argument specifies the digest algorithm to use.
1179 # The SHA1 digest algorithm is the default and is currently
1180 # the only algorithm supported (-sha1).
1182 acl aclname at_step step
1183 # match against the current step during ssl_bump evaluation [fast]
1184 # Never matches and should not be used outside the ssl_bump context.
1186 # At each SslBump step, Squid evaluates ssl_bump directives to find
1187 # the next bumping action (e.g., peek or splice). Valid SslBump step
1188 # values and the corresponding ssl_bump evaluation moments are:
1189 # SslBump1: After getting TCP-level and HTTP CONNECT info.
1190 # SslBump2: After getting SSL Client Hello info.
1191 # SslBump3: After getting SSL Server Hello info.
1193 acl aclname ssl::server_name .foo.com ...
1194 # matches server name obtained from various sources [fast]
1196 # The server name is obtained during Ssl-Bump steps from such sources
1197 # as CONNECT request URI, client SNI, and SSL server certificate CN.
1198 # During each Ssl-Bump step, Squid may improve its understanding of a
1199 # "true server name". Unlike dstdomain, this ACL does not perform
1202 acl aclname ssl::server_name_regex [-i] \.foo\.com ...
1203 # regex matches server name obtained from various sources [fast]
1205 acl aclname any-of acl1 acl2 ...
1206 # match any one of the acls [fast or slow]
1207 # The first matching ACL stops further ACL evaluation.
1209 # ACLs from multiple any-of lines with the same name are ORed.
1210 # For example, A = (a1 or a2) or (a3 or a4) can be written as
1211 # acl A any-of a1 a2
1212 # acl A any-of a3 a4
1214 # This group ACL is fast if all evaluated ACLs in the group are fast
1215 # and slow otherwise.
1217 acl aclname all-of acl1 acl2 ...
1218 # match all of the acls [fast or slow]
1219 # The first mismatching ACL stops further ACL evaluation.
1221 # ACLs from multiple all-of lines with the same name are ORed.
1222 # For example, B = (b1 and b2) or (b3 and b4) can be written as
1223 # acl B all-of b1 b2
1224 # acl B all-of b3 b4
1226 # This group ACL is fast if all evaluated ACLs in the group are fast
1227 # and slow otherwise.
1230 acl macaddress arp 09:00:2b:23:45:67
1231 acl myexample dst_as 1241
1232 acl password proxy_auth REQUIRED
1233 acl fileupload req_mime_type -i ^multipart/form-data$
1234 acl javascript rep_mime_type -i ^application/x-javascript$
1238 # Recommended minimum configuration:
1241 # Example rule allowing access from your local networks.
1242 # Adapt to list your (internal) IP networks from where browsing
1244 acl localnet src 0.0.0.1-0.255.255.255 # RFC 1122 "this" network (LAN)
1245 acl localnet src 10.0.0.0/8 # RFC 1918 local private network (LAN)
1246 acl localnet src 100.64.0.0/10 # RFC 6598 shared address space (CGN)
1247 acl localhet src 169.254.0.0/16 # RFC 3927 link-local (directly plugged) machines
1248 acl localnet src 172.16.0.0/12 # RFC 1918 local private network (LAN)
1249 acl localnet src 192.168.0.0/16 # RFC 1918 local private network (LAN)
1250 acl localnet src fc00::/7 # RFC 4193 local private network range
1251 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1253 acl SSL_ports port 443
1254 acl Safe_ports port 80 # http
1255 acl Safe_ports port 21 # ftp
1256 acl Safe_ports port 443 # https
1257 acl Safe_ports port 70 # gopher
1258 acl Safe_ports port 210 # wais
1259 acl Safe_ports port 1025-65535 # unregistered ports
1260 acl Safe_ports port 280 # http-mgmt
1261 acl Safe_ports port 488 # gss-http
1262 acl Safe_ports port 591 # filemaker
1263 acl Safe_ports port 777 # multiling http
1264 acl CONNECT method CONNECT
1268 NAME: proxy_protocol_access
1270 LOC: Config.accessList.proxyProtocol
1272 DEFAULT_DOC: all TCP connections to ports with require-proxy-header will be denied
1274 Determine which client proxies can be trusted to provide correct
1275 information regarding real client IP address using PROXY protocol.
1277 Requests may pass through a chain of several other proxies
1278 before reaching us. The original source details may by sent in:
1279 * HTTP message Forwarded header, or
1280 * HTTP message X-Forwarded-For header, or
1281 * PROXY protocol connection header.
1283 This directive is solely for validating new PROXY protocol
1284 connections received from a port flagged with require-proxy-header.
1285 It is checked only once after TCP connection setup.
1287 A deny match results in TCP connection closure.
1289 An allow match is required for Squid to permit the corresponding
1290 TCP connection, before Squid even looks for HTTP request headers.
1291 If there is an allow match, Squid starts using PROXY header information
1292 to determine the source address of the connection for all future ACL
1293 checks, logging, etc.
1295 SECURITY CONSIDERATIONS:
1297 Any host from which we accept client IP details can place
1298 incorrect information in the relevant header, and Squid
1299 will use the incorrect information as if it were the
1300 source address of the request. This may enable remote
1301 hosts to bypass any access control restrictions that are
1302 based on the client's source addresses.
1304 This clause only supports fast acl types.
1305 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1308 NAME: follow_x_forwarded_for
1310 IFDEF: FOLLOW_X_FORWARDED_FOR
1311 LOC: Config.accessList.followXFF
1312 DEFAULT_IF_NONE: deny all
1313 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1315 Determine which client proxies can be trusted to provide correct
1316 information regarding real client IP address.
1318 Requests may pass through a chain of several other proxies
1319 before reaching us. The original source details may by sent in:
1320 * HTTP message Forwarded header, or
1321 * HTTP message X-Forwarded-For header, or
1322 * PROXY protocol connection header.
1324 PROXY protocol connections are controlled by the proxy_protocol_access
1325 directive which is checked before this.
1327 If a request reaches us from a source that is allowed by this
1328 directive, then we trust the information it provides regarding
1329 the IP of the client it received from (if any).
1331 For the purpose of ACLs used in this directive the src ACL type always
1332 matches the address we are testing and srcdomain matches its rDNS.
1334 On each HTTP request Squid checks for X-Forwarded-For header fields.
1335 If found the header values are iterated in reverse order and an allow
1336 match is required for Squid to continue on to the next value.
1337 The verification ends when a value receives a deny match, cannot be
1338 tested, or there are no more values to test.
1339 NOTE: Squid does not yet follow the Forwarded HTTP header.
1341 The end result of this process is an IP address that we will
1342 refer to as the indirect client address. This address may
1343 be treated as the client address for access control, ICAP, delay
1344 pools and logging, depending on the acl_uses_indirect_client,
1345 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1346 log_uses_indirect_client and tproxy_uses_indirect_client options.
1348 This clause only supports fast acl types.
1349 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1351 SECURITY CONSIDERATIONS:
1353 Any host from which we accept client IP details can place
1354 incorrect information in the relevant header, and Squid
1355 will use the incorrect information as if it were the
1356 source address of the request. This may enable remote
1357 hosts to bypass any access control restrictions that are
1358 based on the client's source addresses.
1362 acl localhost src 127.0.0.1
1363 acl my_other_proxy srcdomain .proxy.example.com
1364 follow_x_forwarded_for allow localhost
1365 follow_x_forwarded_for allow my_other_proxy
1368 NAME: acl_uses_indirect_client
1371 IFDEF: FOLLOW_X_FORWARDED_FOR
1373 LOC: Config.onoff.acl_uses_indirect_client
1375 Controls whether the indirect client address
1376 (see follow_x_forwarded_for) is used instead of the
1377 direct client address in acl matching.
1379 NOTE: maxconn ACL considers direct TCP links and indirect
1380 clients will always have zero. So no match.
1383 NAME: delay_pool_uses_indirect_client
1386 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1388 LOC: Config.onoff.delay_pool_uses_indirect_client
1390 Controls whether the indirect client address
1391 (see follow_x_forwarded_for) is used instead of the
1392 direct client address in delay pools.
1395 NAME: log_uses_indirect_client
1398 IFDEF: FOLLOW_X_FORWARDED_FOR
1400 LOC: Config.onoff.log_uses_indirect_client
1402 Controls whether the indirect client address
1403 (see follow_x_forwarded_for) is used instead of the
1404 direct client address in the access log.
1407 NAME: tproxy_uses_indirect_client
1410 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1412 LOC: Config.onoff.tproxy_uses_indirect_client
1414 Controls whether the indirect client address
1415 (see follow_x_forwarded_for) is used instead of the
1416 direct client address when spoofing the outgoing client.
1418 This has no effect on requests arriving in non-tproxy
1421 SECURITY WARNING: Usage of this option is dangerous
1422 and should not be used trivially. Correct configuration
1423 of follow_x_forwarded_for with a limited set of trusted
1424 sources is required to prevent abuse of your proxy.
1427 NAME: spoof_client_ip
1429 LOC: Config.accessList.spoof_client_ip
1431 DEFAULT_DOC: Allow spoofing on all TPROXY traffic.
1433 Control client IP address spoofing of TPROXY traffic based on
1434 defined access lists.
1436 spoof_client_ip allow|deny [!]aclname ...
1438 If there are no "spoof_client_ip" lines present, the default
1439 is to "allow" spoofing of any suitable request.
1441 Note that the cache_peer "no-tproxy" option overrides this ACL.
1443 This clause supports fast acl types.
1444 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1449 LOC: Config.accessList.http
1450 DEFAULT_IF_NONE: deny all
1451 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1453 Allowing or Denying access based on defined access lists
1455 To allow or deny a message received on an HTTP, HTTPS, or FTP port:
1456 http_access allow|deny [!]aclname ...
1458 NOTE on default values:
1460 If there are no "access" lines present, the default is to deny
1463 If none of the "access" lines cause a match, the default is the
1464 opposite of the last line in the list. If the last line was
1465 deny, the default is allow. Conversely, if the last line
1466 is allow, the default will be deny. For these reasons, it is a
1467 good idea to have an "deny all" entry at the end of your access
1468 lists to avoid potential confusion.
1470 This clause supports both fast and slow acl types.
1471 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1476 # Recommended minimum Access Permission configuration:
1478 # Deny requests to certain unsafe ports
1479 http_access deny !Safe_ports
1481 # Deny CONNECT to other than secure SSL ports
1482 http_access deny CONNECT !SSL_ports
1484 # Only allow cachemgr access from localhost
1485 http_access allow localhost manager
1486 http_access deny manager
1488 # We strongly recommend the following be uncommented to protect innocent
1489 # web applications running on the proxy server who think the only
1490 # one who can access services on "localhost" is a local user
1491 #http_access deny to_localhost
1494 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1497 # Example rule allowing access from your local networks.
1498 # Adapt localnet in the ACL section to list your (internal) IP networks
1499 # from where browsing should be allowed
1500 http_access allow localnet
1501 http_access allow localhost
1503 # And finally deny all other access to this proxy
1504 http_access deny all
1508 NAME: adapted_http_access http_access2
1510 LOC: Config.accessList.adapted_http
1512 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1514 Allowing or Denying access based on defined access lists
1516 Essentially identical to http_access, but runs after redirectors
1517 and ICAP/eCAP adaptation. Allowing access control based on their
1520 If not set then only http_access is used.
1523 NAME: http_reply_access
1525 LOC: Config.accessList.reply
1527 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1529 Allow replies to client requests. This is complementary to http_access.
1531 http_reply_access allow|deny [!] aclname ...
1533 NOTE: if there are no access lines present, the default is to allow
1536 If none of the access lines cause a match the opposite of the
1537 last line will apply. Thus it is good practice to end the rules
1538 with an "allow all" or "deny all" entry.
1540 This clause supports both fast and slow acl types.
1541 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1546 LOC: Config.accessList.icp
1548 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1550 Allowing or Denying access to the ICP port based on defined
1553 icp_access allow|deny [!]aclname ...
1555 NOTE: The default if no icp_access lines are present is to
1556 deny all traffic. This default may cause problems with peers
1559 This clause only supports fast acl types.
1560 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1562 # Allow ICP queries from local networks only
1563 #icp_access allow localnet
1564 #icp_access deny all
1570 LOC: Config.accessList.htcp
1572 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1574 Allowing or Denying access to the HTCP port based on defined
1577 htcp_access allow|deny [!]aclname ...
1579 See also htcp_clr_access for details on access control for
1580 cache purge (CLR) HTCP messages.
1582 NOTE: The default if no htcp_access lines are present is to
1583 deny all traffic. This default may cause problems with peers
1584 using the htcp option.
1586 This clause only supports fast acl types.
1587 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1589 # Allow HTCP queries from local networks only
1590 #htcp_access allow localnet
1591 #htcp_access deny all
1594 NAME: htcp_clr_access
1597 LOC: Config.accessList.htcp_clr
1599 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1601 Allowing or Denying access to purge content using HTCP based
1602 on defined access lists.
1603 See htcp_access for details on general HTCP access control.
1605 htcp_clr_access allow|deny [!]aclname ...
1607 This clause only supports fast acl types.
1608 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1610 # Allow HTCP CLR requests from trusted peers
1611 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1612 htcp_clr_access allow htcp_clr_peer
1613 htcp_clr_access deny all
1618 LOC: Config.accessList.miss
1620 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1622 Determines whether network access is permitted when satisfying a request.
1625 to force your neighbors to use you as a sibling instead of
1628 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1629 miss_access deny !localclients
1630 miss_access allow all
1632 This means only your local clients are allowed to fetch relayed/MISS
1633 replies from the network and all other clients can only fetch cached
1636 The default for this setting allows all clients who passed the
1637 http_access rules to relay via this proxy.
1639 This clause only supports fast acl types.
1640 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1643 NAME: ident_lookup_access
1647 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1648 LOC: Ident::TheConfig.identLookup
1650 A list of ACL elements which, if matched, cause an ident
1651 (RFC 931) lookup to be performed for this request. For
1652 example, you might choose to always perform ident lookups
1653 for your main multi-user Unix boxes, but not for your Macs
1654 and PCs. By default, ident lookups are not performed for
1657 To enable ident lookups for specific client addresses, you
1658 can follow this example:
1660 acl ident_aware_hosts src 198.168.1.0/24
1661 ident_lookup_access allow ident_aware_hosts
1662 ident_lookup_access deny all
1664 Only src type ACL checks are fully supported. A srcdomain
1665 ACL might work at times, but it will not always provide
1668 This clause only supports fast acl types.
1669 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1672 NAME: reply_body_max_size
1673 COMMENT: size [acl acl...]
1676 DEFAULT_DOC: No limit is applied.
1677 LOC: Config.ReplyBodySize
1679 This option specifies the maximum size of a reply body. It can be
1680 used to prevent users from downloading very large files, such as
1681 MP3's and movies. When the reply headers are received, the
1682 reply_body_max_size lines are processed, and the first line where
1683 all (if any) listed ACLs are true is used as the maximum body size
1686 This size is checked twice. First when we get the reply headers,
1687 we check the content-length value. If the content length value exists
1688 and is larger than the allowed size, the request is denied and the
1689 user receives an error message that says "the request or reply
1690 is too large." If there is no content-length, and the reply
1691 size exceeds this limit, the client's connection is just closed
1692 and they will receive a partial reply.
1694 WARNING: downstream caches probably can not detect a partial reply
1695 if there is no content-length header, so they will cache
1696 partial responses and give them out as hits. You should NOT
1697 use this option if you have downstream caches.
1699 WARNING: A maximum size smaller than the size of squid's error messages
1700 will cause an infinite loop and crash squid. Ensure that the smallest
1701 non-zero value you use is greater that the maximum header size plus
1702 the size of your largest error page.
1704 If you set this parameter none (the default), there will be
1707 Configuration Format is:
1708 reply_body_max_size SIZE UNITS [acl ...]
1710 reply_body_max_size 10 MB
1714 NAME: on_unsupported_protocol
1715 TYPE: on_unsupported_protocol
1716 LOC: Config.accessList.on_unsupported_protocol
1718 DEFAULT_DOC: Respond with an error message to unidentifiable traffic
1720 Determines Squid behavior when encountering strange requests at the
1721 beginning of an accepted TCP connection or the beginning of a bumped
1722 CONNECT tunnel. Controlling Squid reaction to unexpected traffic is
1723 especially useful in interception environments where Squid is likely
1724 to see connections for unsupported protocols that Squid should either
1725 terminate or tunnel at TCP level.
1727 on_unsupported_protocol <action> [!]acl ...
1729 The first matching action wins. Only fast ACLs are supported.
1731 Supported actions are:
1733 tunnel: Establish a TCP connection with the intended server and
1734 blindly shovel TCP packets between the client and server.
1736 respond: Respond with an error message, using the transfer protocol
1737 for the Squid port that received the request (e.g., HTTP
1738 for connections intercepted at the http_port). This is the
1741 Squid expects the following traffic patterns:
1743 http_port: a plain HTTP request
1744 https_port: SSL/TLS handshake followed by an [encrypted] HTTP request
1745 ftp_port: a plain FTP command (no on_unsupported_protocol support yet!)
1746 CONNECT tunnel on http_port: same as https_port
1747 CONNECT tunnel on https_port: same as https_port
1749 Currently, this directive has effect on intercepted connections and
1750 bumped tunnels only. Other cases are not supported because Squid
1751 cannot know the intended destination of other traffic.
1754 # define what Squid errors indicate receiving non-HTTP traffic:
1755 acl foreignProtocol squid_error ERR_PROTOCOL_UNKNOWN ERR_TOO_BIG
1756 # define what Squid errors indicate receiving nothing:
1757 acl serverTalksFirstProtocol squid_error ERR_REQUEST_START_TIMEOUT
1758 # tunnel everything that does not look like HTTP:
1759 on_unsupported_protocol tunnel foreignProtocol
1760 # tunnel if we think the client waits for the server to talk first:
1761 on_unsupported_protocol tunnel serverTalksFirstProtocol
1762 # in all other error cases, just send an HTTP "error page" response:
1763 on_unsupported_protocol respond all
1765 See also: squid_error ACL
1770 -----------------------------------------------------------------------------
1773 NAME: http_port ascii_port
1778 Usage: port [mode] [options]
1779 hostname:port [mode] [options]
1780 1.2.3.4:port [mode] [options]
1782 The socket addresses where Squid will listen for HTTP client
1783 requests. You may specify multiple socket addresses.
1784 There are three forms: port alone, hostname with port, and
1785 IP address with port. If you specify a hostname or IP
1786 address, Squid binds the socket to that specific
1787 address. Most likely, you do not need to bind to a specific
1788 address, so you can use the port number alone.
1790 If you are running Squid in accelerator mode, you
1791 probably want to listen on port 80 also, or instead.
1793 The -a command line option may be used to specify additional
1794 port(s) where Squid listens for proxy request. Such ports will
1795 be plain proxy ports with no options.
1797 You may specify multiple socket addresses on multiple lines.
1801 intercept Support for IP-Layer NAT interception delivering
1802 traffic to this Squid port.
1803 NP: disables authentication on the port.
1805 tproxy Support Linux TPROXY (or BSD divert-to) with spoofing
1806 of outgoing connections using the client IP address.
1807 NP: disables authentication on the port.
1809 accel Accelerator / reverse proxy mode
1811 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1812 establish secure connection with the client and with
1813 the server, decrypt HTTPS messages as they pass through
1814 Squid, and treat them as unencrypted HTTP messages,
1815 becoming the man-in-the-middle.
1817 The ssl_bump option is required to fully enable
1818 bumping of CONNECT requests.
1820 Omitting the mode flag causes default forward proxy mode to be used.
1823 Accelerator Mode Options:
1825 defaultsite=domainname
1826 What to use for the Host: header if it is not present
1827 in a request. Determines what site (not origin server)
1828 accelerators should consider the default.
1830 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1832 protocol= Protocol to reconstruct accelerated and intercepted
1833 requests with. Defaults to HTTP/1.1 for http_port and
1834 HTTPS/1.1 for https_port.
1835 When an unsupported value is configured Squid will
1836 produce a FATAL error.
1837 Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
1839 vport Virtual host port support. Using the http_port number
1840 instead of the port passed on Host: headers.
1842 vport=NN Virtual host port support. Using the specified port
1843 number instead of the port passed on Host: headers.
1846 Act as if this Squid is the origin server.
1847 This currently means generate new Date: and Expires:
1848 headers on HIT instead of adding Age:.
1850 ignore-cc Ignore request Cache-Control headers.
1852 WARNING: This option violates HTTP specifications if
1853 used in non-accelerator setups.
1855 allow-direct Allow direct forwarding in accelerator mode. Normally
1856 accelerated requests are denied direct forwarding as if
1857 never_direct was used.
1859 WARNING: this option opens accelerator mode to security
1860 vulnerabilities usually only affecting in interception
1861 mode. Make sure to protect forwarding with suitable
1862 http_access rules when using this.
1865 SSL Bump Mode Options:
1866 In addition to these options ssl-bump requires TLS/SSL options.
1868 generate-host-certificates[=<on|off>]
1869 Dynamically create SSL server certificates for the
1870 destination hosts of bumped CONNECT requests.When
1871 enabled, the cert and key options are used to sign
1872 generated certificates. Otherwise generated
1873 certificate will be selfsigned.
1874 If there is a CA certificate lifetime of the generated
1875 certificate equals lifetime of the CA certificate. If
1876 generated certificate is selfsigned lifetime is three
1878 This option is enabled by default when ssl-bump is used.
1879 See the ssl-bump option above for more information.
1881 dynamic_cert_mem_cache_size=SIZE
1882 Approximate total RAM size spent on cached generated
1883 certificates. If set to zero, caching is disabled. The
1884 default value is 4MB.
1888 cert= Path to SSL certificate (PEM format).
1890 key= Path to SSL private key file (PEM format)
1891 if not specified, the certificate file is
1892 assumed to be a combined certificate and
1895 cipher= Colon separated list of supported ciphers.
1896 NOTE: some ciphers such as EDH ciphers depend on
1897 additional settings. If those settings are
1898 omitted the ciphers may be silently ignored
1899 by the OpenSSL library.
1901 options= Various SSL implementation options. The most important
1904 NO_SSLv3 Disallow the use of SSLv3
1906 NO_TLSv1 Disallow the use of TLSv1.0
1908 NO_TLSv1_1 Disallow the use of TLSv1.1
1910 NO_TLSv1_2 Disallow the use of TLSv1.2
1913 Always create a new key when using
1914 temporary/ephemeral DH key exchanges
1917 Enable ephemeral ECDH key exchange.
1918 The adopted curve should be specified
1919 using the tls-dh option.
1922 Disable use of RFC5077 session tickets.
1923 Some servers may have problems
1924 understanding the TLS extension due
1925 to ambiguous specification in RFC4507.
1927 ALL Enable various bug workarounds
1928 suggested as "harmless" by OpenSSL
1929 Be warned that this reduces SSL/TLS
1930 strength to some attacks.
1932 See the OpenSSL SSL_CTX_set_options documentation for a
1935 clientca= File containing the list of CAs to use when
1936 requesting a client certificate.
1938 tls-cafile= PEM file containing CA certificates to use when verifying
1939 client certificates. If not configured clientca will be
1940 used. May be repeated to load multiple files.
1942 capath= Directory containing additional CA certificates
1943 and CRL lists to use when verifying client certificates.
1944 Requires OpenSSL or LibreSSL.
1946 crlfile= File of additional CRL lists to use when verifying
1947 the client certificate, in addition to CRLs stored in
1948 the capath. Implies VERIFY_CRL flag below.
1951 File containing DH parameters for temporary/ephemeral DH key
1952 exchanges, optionally prefixed by a curve for ephemeral ECDH
1954 See OpenSSL documentation for details on how to create the
1955 DH parameter file. Supported curves for ECDH can be listed
1956 using the "openssl ecparam -list_curves" command.
1957 WARNING: EDH and EECDH ciphers will be silently disabled if
1958 this option is not set.
1960 sslflags= Various flags modifying the use of SSL:
1962 Don't request client certificates
1963 immediately, but wait until acl processing
1964 requires a certificate (not yet implemented).
1966 Don't allow for session reuse. Each connection
1967 will result in a new SSL session.
1969 Verify CRL lists when accepting client
1972 Verify CRL lists for all certificates in the
1973 client certificate chain.
1976 Do not use the system default Trusted CA.
1978 tls-no-npn Do not use the TLS NPN extension to advertise HTTP/1.1.
1980 sslcontext= SSL session ID context identifier.
1984 connection-auth[=on|off]
1985 use connection-auth=off to tell Squid to prevent
1986 forwarding Microsoft connection oriented authentication
1987 (NTLM, Negotiate and Kerberos)
1989 disable-pmtu-discovery=
1990 Control Path-MTU discovery usage:
1991 off lets OS decide on what to do (default).
1992 transparent disable PMTU discovery when transparent
1994 always disable always PMTU discovery.
1996 In many setups of transparently intercepting proxies
1997 Path-MTU discovery can not work on traffic towards the
1998 clients. This is the case when the intercepting device
1999 does not fully track connections and fails to forward
2000 ICMP must fragment messages to the cache server. If you
2001 have such setup and experience that certain clients
2002 sporadically hang or never complete requests set
2003 disable-pmtu-discovery option to 'transparent'.
2005 name= Specifies a internal name for the port. Defaults to
2006 the port specification (port or addr:port)
2008 tcpkeepalive[=idle,interval,timeout]
2009 Enable TCP keepalive probes of idle connections.
2010 In seconds; idle is the initial time before TCP starts
2011 probing the connection, interval how often to probe, and
2012 timeout the time before giving up.
2014 require-proxy-header
2015 Require PROXY protocol version 1 or 2 connections.
2016 The proxy_protocol_access is required to whitelist
2017 downstream proxies which can be trusted.
2019 If you run Squid on a dual-homed machine with an internal
2020 and an external interface we recommend you to specify the
2021 internal address:port in http_port. This way Squid will only be
2022 visible on the internal address.
2026 # Squid normally listens to port 3128
2027 http_port @DEFAULT_HTTP_PORT@
2032 IFDEF: USE_GNUTLS||USE_OPENSSL
2037 Usage: [ip:]port [mode] cert=certificate.pem [options]
2039 The socket address where Squid will listen for client requests made
2040 over TLS or SSL connections. Commonly referred to as HTTPS.
2042 This is most useful for situations where you are running squid in
2043 accelerator mode and you want to do the TLS work at the accelerator level.
2045 You may specify multiple socket addresses on multiple lines,
2046 each with their own certificate and/or options.
2048 The TLS cert= option is mandatory on HTTPS ports.
2050 See http_port for a list of modes and options.
2058 Enables Native FTP proxy by specifying the socket address where Squid
2059 listens for FTP client requests. See http_port directive for various
2060 ways to specify the listening address and mode.
2062 Usage: ftp_port address [mode] [options]
2064 WARNING: This is a new, experimental, complex feature that has seen
2065 limited production exposure. Some Squid modules (e.g., caching) do not
2066 currently work with native FTP proxying, and many features have not
2067 even been tested for compatibility. Test well before deploying!
2069 Native FTP proxying differs substantially from proxying HTTP requests
2070 with ftp:// URIs because Squid works as an FTP server and receives
2071 actual FTP commands (rather than HTTP requests with FTP URLs).
2073 Native FTP commands accepted at ftp_port are internally converted or
2074 wrapped into HTTP-like messages. The same happens to Native FTP
2075 responses received from FTP origin servers. Those HTTP-like messages
2076 are shoveled through regular access control and adaptation layers
2077 between the FTP client and the FTP origin server. This allows Squid to
2078 examine, adapt, block, and log FTP exchanges. Squid reuses most HTTP
2079 mechanisms when shoveling wrapped FTP messages. For example,
2080 http_access and adaptation_access directives are used.
2084 intercept Same as http_port intercept. The FTP origin address is
2085 determined based on the intended destination of the
2086 intercepted connection.
2088 tproxy Support Linux TPROXY for spoofing outgoing
2089 connections using the client IP address.
2090 NP: disables authentication and maybe IPv6 on the port.
2092 By default (i.e., without an explicit mode option), Squid extracts the
2093 FTP origin address from the login@origin parameter of the FTP USER
2094 command. Many popular FTP clients support such native FTP proxying.
2098 name=token Specifies an internal name for the port. Defaults to
2099 the port address. Usable with myportname ACL.
2102 Enables tracking of FTP directories by injecting extra
2103 PWD commands and adjusting Request-URI (in wrapping
2104 HTTP requests) to reflect the current FTP server
2105 directory. Tracking is disabled by default.
2107 protocol=FTP Protocol to reconstruct accelerated and intercepted
2108 requests with. Defaults to FTP. No other accepted
2109 values have been tested with. An unsupported value
2110 results in a FATAL error. Accepted values are FTP,
2111 HTTP (or HTTP/1.1), and HTTPS (or HTTPS/1.1).
2113 Other http_port modes and options that are not specific to HTTP and
2114 HTTPS may also work.
2117 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
2120 LOC: Ip::Qos::TheConfig.tosToServer
2122 Allows you to select a TOS/Diffserv value for packets outgoing
2123 on the server side, based on an ACL.
2125 tcp_outgoing_tos ds-field [!]aclname ...
2127 Example where normal_service_net uses the TOS value 0x00
2128 and good_service_net uses 0x20
2130 acl normal_service_net src 10.0.0.0/24
2131 acl good_service_net src 10.0.1.0/24
2132 tcp_outgoing_tos 0x00 normal_service_net
2133 tcp_outgoing_tos 0x20 good_service_net
2135 TOS/DSCP values really only have local significance - so you should
2136 know what you're specifying. For more information, see RFC2474,
2137 RFC2475, and RFC3260.
2139 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2140 "default" to use whatever default your host has.
2141 Note that only multiples of 4 are usable as the two rightmost bits have
2142 been redefined for use by ECN (RFC 3168 section 23.1).
2143 The squid parser will enforce this by masking away the ECN bits.
2145 Processing proceeds in the order specified, and stops at first fully
2148 Only fast ACLs are supported.
2151 NAME: clientside_tos
2154 LOC: Ip::Qos::TheConfig.tosToClient
2156 Allows you to select a TOS/DSCP value for packets being transmitted
2157 on the client-side, based on an ACL.
2159 clientside_tos ds-field [!]aclname ...
2161 Example where normal_service_net uses the TOS value 0x00
2162 and good_service_net uses 0x20
2164 acl normal_service_net src 10.0.0.0/24
2165 acl good_service_net src 10.0.1.0/24
2166 clientside_tos 0x00 normal_service_net
2167 clientside_tos 0x20 good_service_net
2169 Note: This feature is incompatible with qos_flows. Any TOS values set here
2170 will be overwritten by TOS values in qos_flows.
2172 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2173 "default" to use whatever default your host has.
2174 Note that only multiples of 4 are usable as the two rightmost bits have
2175 been redefined for use by ECN (RFC 3168 section 23.1).
2176 The squid parser will enforce this by masking away the ECN bits.
2180 NAME: tcp_outgoing_mark
2182 IFDEF: SO_MARK&&USE_LIBCAP
2184 LOC: Ip::Qos::TheConfig.nfmarkToServer
2186 Allows you to apply a Netfilter mark value to outgoing packets
2187 on the server side, based on an ACL.
2189 tcp_outgoing_mark mark-value [!]aclname ...
2191 Example where normal_service_net uses the mark value 0x00
2192 and good_service_net uses 0x20
2194 acl normal_service_net src 10.0.0.0/24
2195 acl good_service_net src 10.0.1.0/24
2196 tcp_outgoing_mark 0x00 normal_service_net
2197 tcp_outgoing_mark 0x20 good_service_net
2199 Only fast ACLs are supported.
2202 NAME: clientside_mark
2204 IFDEF: SO_MARK&&USE_LIBCAP
2206 LOC: Ip::Qos::TheConfig.nfmarkToClient
2208 Allows you to apply a Netfilter mark value to packets being transmitted
2209 on the client-side, based on an ACL.
2211 clientside_mark mark-value [!]aclname ...
2213 Example where normal_service_net uses the mark value 0x00
2214 and good_service_net uses 0x20
2216 acl normal_service_net src 10.0.0.0/24
2217 acl good_service_net src 10.0.1.0/24
2218 clientside_mark 0x00 normal_service_net
2219 clientside_mark 0x20 good_service_net
2221 Note: This feature is incompatible with qos_flows. Any mark values set here
2222 will be overwritten by mark values in qos_flows.
2229 LOC: Ip::Qos::TheConfig
2231 Allows you to select a TOS/DSCP value to mark outgoing
2232 connections to the client, based on where the reply was sourced.
2233 For platforms using netfilter, allows you to set a netfilter mark
2234 value instead of, or in addition to, a TOS value.
2236 By default this functionality is disabled. To enable it with the default
2237 settings simply use "qos_flows mark" or "qos_flows tos". Default
2238 settings will result in the netfilter mark or TOS value being copied
2239 from the upstream connection to the client. Note that it is the connection
2240 CONNMARK value not the packet MARK value that is copied.
2242 It is not currently possible to copy the mark or TOS value from the
2243 client to the upstream connection request.
2245 TOS values really only have local significance - so you should
2246 know what you're specifying. For more information, see RFC2474,
2247 RFC2475, and RFC3260.
2249 The TOS/DSCP byte must be exactly that - a octet value 0 - 255.
2250 Note that only multiples of 4 are usable as the two rightmost bits have
2251 been redefined for use by ECN (RFC 3168 section 23.1).
2252 The squid parser will enforce this by masking away the ECN bits.
2254 Mark values can be any unsigned 32-bit integer value.
2256 This setting is configured by setting the following values:
2258 tos|mark Whether to set TOS or netfilter mark values
2260 local-hit=0xFF Value to mark local cache hits.
2262 sibling-hit=0xFF Value to mark hits from sibling peers.
2264 parent-hit=0xFF Value to mark hits from parent peers.
2266 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2267 over the preserve-miss feature (see below), unless
2268 mask is specified, in which case only the bits
2269 specified in the mask are written.
2271 The TOS variant of the following features are only possible on Linux
2272 and require your kernel to be patched with the TOS preserving ZPH
2273 patch, available from http://zph.bratcheda.org
2274 No patch is needed to preserve the netfilter mark, which will work
2275 with all variants of netfilter.
2277 disable-preserve-miss
2278 This option disables the preservation of the TOS or netfilter
2279 mark. By default, the existing TOS or netfilter mark value of
2280 the response coming from the remote server will be retained
2281 and masked with miss-mark.
2282 NOTE: in the case of a netfilter mark, the mark must be set on
2283 the connection (using the CONNMARK target) not on the packet
2287 Allows you to mask certain bits in the TOS or mark value
2288 received from the remote server, before copying the value to
2289 the TOS sent towards clients.
2290 Default for tos: 0xFF (TOS from server is not changed).
2291 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2293 All of these features require the --enable-zph-qos compilation flag
2294 (enabled by default). Netfilter marking also requires the
2295 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2296 libcap 2.09+ (--with-libcap).
2300 NAME: tcp_outgoing_address
2303 DEFAULT_DOC: Address selection is performed by the operating system.
2304 LOC: Config.accessList.outgoing_address
2306 Allows you to map requests to different outgoing IP addresses
2307 based on the username or source address of the user making
2310 tcp_outgoing_address ipaddr [[!]aclname] ...
2313 Forwarding clients with dedicated IPs for certain subnets.
2315 acl normal_service_net src 10.0.0.0/24
2316 acl good_service_net src 10.0.2.0/24
2318 tcp_outgoing_address 2001:db8::c001 good_service_net
2319 tcp_outgoing_address 10.1.0.2 good_service_net
2321 tcp_outgoing_address 2001:db8::beef normal_service_net
2322 tcp_outgoing_address 10.1.0.1 normal_service_net
2324 tcp_outgoing_address 2001:db8::1
2325 tcp_outgoing_address 10.1.0.3
2327 Processing proceeds in the order specified, and stops at first fully
2330 Squid will add an implicit IP version test to each line.
2331 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2332 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2335 NOTE: The use of this directive using client dependent ACLs is
2336 incompatible with the use of server side persistent connections. To
2337 ensure correct results it is best to set server_persistent_connections
2338 to off when using this directive in such configurations.
2340 NOTE: The use of this directive to set a local IP on outgoing TCP links
2341 is incompatible with using TPROXY to set client IP out outbound TCP links.
2342 When needing to contact peers use the no-tproxy cache_peer option and the
2343 client_dst_passthru directive re-enable normal forwarding such as this.
2347 NAME: host_verify_strict
2350 LOC: Config.onoff.hostStrictVerify
2352 Regardless of this option setting, when dealing with intercepted
2353 traffic, Squid always verifies that the destination IP address matches
2354 the Host header domain or IP (called 'authority form URL').
2356 This enforcement is performed to satisfy a MUST-level requirement in
2357 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2358 authority of the origin server or gateway given by the original URL".
2361 Squid always responds with an HTTP 409 (Conflict) error
2362 page and logs a security warning if there is no match.
2364 Squid verifies that the destination IP address matches
2365 the Host header for forward-proxy and reverse-proxy traffic
2366 as well. For those traffic types, Squid also enables the
2367 following checks, comparing the corresponding Host header
2368 and Request-URI components:
2370 * The host names (domain or IP) must be identical,
2371 but valueless or missing Host header disables all checks.
2372 For the two host names to match, both must be either IP
2375 * Port numbers must be identical, but if a port is missing
2376 the scheme-default port is assumed.
2379 When set to OFF (the default):
2380 Squid allows suspicious requests to continue but logs a
2381 security warning and blocks caching of the response.
2383 * Forward-proxy traffic is not checked at all.
2385 * Reverse-proxy traffic is not checked at all.
2387 * Intercepted traffic which passes verification is handled
2388 according to client_dst_passthru.
2390 * Intercepted requests which fail verification are sent
2391 to the client original destination instead of DIRECT.
2392 This overrides 'client_dst_passthru off'.
2394 For now suspicious intercepted CONNECT requests are always
2395 responded to with an HTTP 409 (Conflict) error page.
2400 As described in CVE-2009-0801 when the Host: header alone is used
2401 to determine the destination of a request it becomes trivial for
2402 malicious scripts on remote websites to bypass browser same-origin
2403 security policy and sandboxing protections.
2405 The cause of this is that such applets are allowed to perform their
2406 own HTTP stack, in which case the same-origin policy of the browser
2407 sandbox only verifies that the applet tries to contact the same IP
2408 as from where it was loaded at the IP level. The Host: header may
2409 be different from the connected IP and approved origin.
2413 NAME: client_dst_passthru
2416 LOC: Config.onoff.client_dst_passthru
2418 With NAT or TPROXY intercepted traffic Squid may pass the request
2419 directly to the original client destination IP or seek a faster
2420 source using the HTTP Host header.
2422 Using Host to locate alternative servers can provide faster
2423 connectivity with a range of failure recovery options.
2424 But can also lead to connectivity trouble when the client and
2425 server are attempting stateful interactions unaware of the proxy.
2427 This option (on by default) prevents alternative DNS entries being
2428 located to send intercepted traffic DIRECT to an origin server.
2429 The clients original destination IP and port will be used instead.
2431 Regardless of this option setting, when dealing with intercepted
2432 traffic Squid will verify the Host: header and any traffic which
2433 fails Host verification will be treated as if this option were ON.
2435 see host_verify_strict for details on the verification process.
2440 -----------------------------------------------------------------------------
2443 NAME: tls_outgoing_options
2444 IFDEF: USE_GNUTLS||USE_OPENSSL
2445 TYPE: securePeerOptions
2446 DEFAULT: min-version=1.0
2447 LOC: Security::ProxyOutgoingConfig
2449 disable Do not support https:// URLs.
2451 cert=/path/to/client/certificate
2452 A client TLS certificate to use when connecting.
2454 key=/path/to/client/private_key
2455 The private TLS key corresponding to the cert= above.
2456 If key= is not specified cert= is assumed to reference
2457 a PEM file containing both the certificate and the key.
2459 cipher=... The list of valid TLS ciphers to use.
2462 The minimum TLS protocol version to permit.
2463 To control SSLv3 use the options= parameter.
2464 Supported Values: 1.0 (default), 1.1, 1.2
2466 options=... Specify various TLS/SSL implementation options:
2468 NO_SSLv3 Disallow the use of SSLv3
2470 NO_TLSv1 Disallow the use of TLSv1.0
2472 NO_TLSv1_1 Disallow the use of TLSv1.1
2474 NO_TLSv1_2 Disallow the use of TLSv1.2
2477 Always create a new key when using
2478 temporary/ephemeral DH key exchanges
2481 Disable use of RFC5077 session tickets.
2482 Some servers may have problems
2483 understanding the TLS extension due
2484 to ambiguous specification in RFC4507.
2486 ALL Enable various bug workarounds
2487 suggested as "harmless" by OpenSSL
2488 Be warned that this reduces SSL/TLS
2489 strength to some attacks.
2491 See the OpenSSL SSL_CTX_set_options documentation for a
2494 cafile= PEM file containing CA certificates to use when verifying
2495 the peer certificate. May be repeated to load multiple files.
2497 capath= A directory containing additional CA certificates to
2498 use when verifying the peer certificate.
2499 Requires OpenSSL or LibreSSL.
2501 crlfile=... A certificate revocation list file to use when
2502 verifying the peer certificate.
2504 flags=... Specify various flags modifying the TLS implementation:
2507 Accept certificates even if they fail to
2510 Don't verify the peer certificate
2511 matches the server name
2513 no-default-ca Do not use the system default Trusted CA.
2515 domain= The peer name as advertised in its certificate.
2516 Used for verifying the correctness of the received peer
2517 certificate. If not specified the peer hostname will be
2523 -----------------------------------------------------------------------------
2526 NAME: ssl_unclean_shutdown
2530 LOC: Config.SSL.unclean_shutdown
2532 Some browsers (especially MSIE) bugs out on SSL shutdown
2539 LOC: Config.SSL.ssl_engine
2542 The OpenSSL engine to use. You will need to set this if you
2543 would like to use hardware SSL acceleration for example.
2546 NAME: sslproxy_session_ttl
2549 LOC: Config.SSL.session_ttl
2552 Sets the timeout value for SSL sessions
2555 NAME: sslproxy_session_cache_size
2558 LOC: Config.SSL.sessionCacheSize
2561 Sets the cache size to use for ssl session
2564 NAME: sslproxy_foreign_intermediate_certs
2567 LOC: Config.ssl_client.foreignIntermediateCertsPath
2570 Many origin servers fail to send their full server certificate
2571 chain for verification, assuming the client already has or can
2572 easily locate any missing intermediate certificates.
2574 Squid uses the certificates from the specified file to fill in
2575 these missing chains when trying to validate origin server
2578 The file is expected to contain zero or more PEM-encoded
2579 intermediate certificates. These certificates are not treated
2580 as trusted root certificates, and any self-signed certificate in
2581 this file will be ignored.
2583 This directive may be repeated to load multiple files.
2586 NAME: sslproxy_cert_sign_hash
2589 LOC: Config.SSL.certSignHash
2592 Sets the hashing algorithm to use when signing generated certificates.
2593 Valid algorithm names depend on the OpenSSL library used. The following
2594 names are usually available: sha1, sha256, sha512, and md5. Please see
2595 your OpenSSL library manual for the available hashes. By default, Squids
2596 that support this option use sha256 hashes.
2598 Squid does not forcefully purge cached certificates that were generated
2599 with an algorithm other than the currently configured one. They remain
2600 in the cache, subject to the regular cache eviction policy, and become
2601 useful if the algorithm changes again.
2606 TYPE: sslproxy_ssl_bump
2607 LOC: Config.accessList.ssl_bump
2608 DEFAULT_DOC: Become a TCP tunnel without decrypting proxied traffic.
2611 This option is consulted when a CONNECT request is received on
2612 an http_port (or a new connection is intercepted at an
2613 https_port), provided that port was configured with an ssl-bump
2614 flag. The subsequent data on the connection is either treated as
2615 HTTPS and decrypted OR tunneled at TCP level without decryption,
2616 depending on the first matching bumping "action".
2618 ssl_bump <action> [!]acl ...
2620 The following bumping actions are currently supported:
2623 Become a TCP tunnel without decrypting proxied traffic.
2624 This is the default action.
2627 Establish a secure connection with the server and, using a
2628 mimicked server certificate, with the client.
2631 Receive client (step SslBump1) or server (step SslBump2)
2632 certificate while preserving the possibility of splicing the
2633 connection. Peeking at the server certificate (during step 2)
2634 usually precludes bumping of the connection at step 3.
2637 Receive client (step SslBump1) or server (step SslBump2)
2638 certificate while preserving the possibility of bumping the
2639 connection. Staring at the server certificate (during step 2)
2640 usually precludes splicing of the connection at step 3.
2643 Close client and server connections.
2645 Backward compatibility actions available at step SslBump1:
2648 Bump the connection. Establish a secure connection with the
2649 client first, then connect to the server. This old mode does
2650 not allow Squid to mimic server SSL certificate and does not
2651 work with intercepted SSL connections.
2654 Bump the connection. Establish a secure connection with the
2655 server first, then establish a secure connection with the
2656 client, using a mimicked server certificate. Works with both
2657 CONNECT requests and intercepted SSL connections, but does
2658 not allow to make decisions based on SSL handshake info.
2661 Decide whether to bump or splice the connection based on
2662 client-to-squid and server-to-squid SSL hello messages.
2666 Same as the "splice" action.
2668 All ssl_bump rules are evaluated at each of the supported bumping
2669 steps. Rules with actions that are impossible at the current step are
2670 ignored. The first matching ssl_bump action wins and is applied at the
2671 end of the current step. If no rules match, the splice action is used.
2672 See the at_step ACL for a list of the supported SslBump steps.
2674 This clause supports both fast and slow acl types.
2675 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2677 See also: http_port ssl-bump, https_port ssl-bump, and acl at_step.
2680 # Example: Bump all requests except those originating from
2681 # localhost or those going to example.com.
2683 acl broken_sites dstdomain .example.com
2684 ssl_bump splice localhost
2685 ssl_bump splice broken_sites
2689 NAME: sslproxy_cert_error
2692 DEFAULT_DOC: Server certificate errors terminate the transaction.
2693 LOC: Config.ssl_client.cert_error
2696 Use this ACL to bypass server certificate validation errors.
2698 For example, the following lines will bypass all validation errors
2699 when talking to servers for example.com. All other
2700 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2702 acl BrokenButTrustedServers dstdomain example.com
2703 sslproxy_cert_error allow BrokenButTrustedServers
2704 sslproxy_cert_error deny all
2706 This clause only supports fast acl types.
2707 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2708 Using slow acl types may result in server crashes
2710 Without this option, all server certificate validation errors
2711 terminate the transaction to protect Squid and the client.
2713 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2714 but should not happen unless your OpenSSL library is buggy.
2717 Bypassing validation errors is dangerous because an
2718 error usually implies that the server cannot be trusted
2719 and the connection may be insecure.
2721 See also: sslproxy_flags and DONT_VERIFY_PEER.
2724 NAME: sslproxy_cert_sign
2727 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2728 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2729 POSTSCRIPTUM: signTrusted all
2730 TYPE: sslproxy_cert_sign
2731 LOC: Config.ssl_client.cert_sign
2734 sslproxy_cert_sign <signing algorithm> acl ...
2736 The following certificate signing algorithms are supported:
2739 Sign using the configured CA certificate which is usually
2740 placed in and trusted by end-user browsers. This is the
2741 default for trusted origin server certificates.
2744 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2745 This is the default for untrusted origin server certificates
2746 that are not self-signed (see ssl::certUntrusted).
2749 Sign using a self-signed certificate with the right CN to
2750 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2751 browser. This is the default for self-signed origin server
2752 certificates (see ssl::certSelfSigned).
2754 This clause only supports fast acl types.
2756 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2757 signing algorithm to generate the certificate and ignores all
2758 subsequent sslproxy_cert_sign options (the first match wins). If no
2759 acl(s) match, the default signing algorithm is determined by errors
2760 detected when obtaining and validating the origin server certificate.
2762 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2763 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2764 CONNECT request that carries a domain name. In all other cases (CONNECT
2765 to an IP address or an intercepted SSL connection), Squid cannot detect
2766 the domain mismatch at certificate generation time when
2767 bump-server-first is used.
2770 NAME: sslproxy_cert_adapt
2773 TYPE: sslproxy_cert_adapt
2774 LOC: Config.ssl_client.cert_adapt
2777 sslproxy_cert_adapt <adaptation algorithm> acl ...
2779 The following certificate adaptation algorithms are supported:
2782 Sets the "Not After" property to the "Not After" property of
2783 the CA certificate used to sign generated certificates.
2786 Sets the "Not Before" property to the "Not Before" property of
2787 the CA certificate used to sign generated certificates.
2789 setCommonName or setCommonName{CN}
2790 Sets Subject.CN property to the host name specified as a
2791 CN parameter or, if no explicit CN parameter was specified,
2792 extracted from the CONNECT request. It is a misconfiguration
2793 to use setCommonName without an explicit parameter for
2794 intercepted or tproxied SSL connections.
2796 This clause only supports fast acl types.
2798 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2799 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2800 corresponding adaptation algorithm to generate the certificate and
2801 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2802 group (i.e., the first match wins within each algorithm group). If no
2803 acl(s) match, the default mimicking action takes place.
2805 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2806 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2807 CONNECT request that carries a domain name. In all other cases (CONNECT
2808 to an IP address or an intercepted SSL connection), Squid cannot detect
2809 the domain mismatch at certificate generation time when
2810 bump-server-first is used.
2813 NAME: sslpassword_program
2816 LOC: Config.Program.ssl_password
2819 Specify a program used for entering SSL key passphrases
2820 when using encrypted SSL certificate keys. If not specified
2821 keys must either be unencrypted, or Squid started with the -N
2822 option to allow it to query interactively for the passphrase.
2824 The key file name is given as argument to the program allowing
2825 selection of the right password if you have multiple encrypted
2830 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2831 -----------------------------------------------------------------------------
2834 NAME: sslcrtd_program
2837 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2838 LOC: Ssl::TheConfig.ssl_crtd
2840 Specify the location and options of the executable for ssl_crtd process.
2841 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2842 For more information use:
2843 @DEFAULT_SSL_CRTD@ -h
2846 NAME: sslcrtd_children
2847 TYPE: HelperChildConfig
2849 DEFAULT: 32 startup=5 idle=1
2850 LOC: Ssl::TheConfig.ssl_crtdChildren
2852 The maximum number of processes spawn to service ssl server.
2853 The maximum this may be safely set to is 32.
2855 The startup= and idle= options allow some measure of skew in your
2860 Sets the minimum number of processes to spawn when Squid
2861 starts or reconfigures. When set to zero the first request will
2862 cause spawning of the first child process to handle it.
2864 Starting too few children temporary slows Squid under load while it
2865 tries to spawn enough additional processes to cope with traffic.
2869 Sets a minimum of how many processes Squid is to try and keep available
2870 at all times. When traffic begins to rise above what the existing
2871 processes can handle this many more will be spawned up to the maximum
2872 configured. A minimum setting of 1 is required.
2876 Sets the maximum number of queued requests.
2877 If the queued requests exceed queue size for more than 3 minutes
2878 squid aborts its operation.
2879 The default value is set to 2*numberofchildren.
2881 You must have at least one ssl_crtd process.
2884 NAME: sslcrtvalidator_program
2888 LOC: Ssl::TheConfig.ssl_crt_validator
2890 Specify the location and options of the executable for ssl_crt_validator
2893 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
2896 ttl=n TTL in seconds for cached results. The default is 60 secs
2897 cache=n limit the result cache size. The default value is 2048
2900 NAME: sslcrtvalidator_children
2901 TYPE: HelperChildConfig
2903 DEFAULT: 32 startup=5 idle=1 concurrency=1
2904 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2906 The maximum number of processes spawn to service SSL server.
2907 The maximum this may be safely set to is 32.
2909 The startup= and idle= options allow some measure of skew in your
2914 Sets the minimum number of processes to spawn when Squid
2915 starts or reconfigures. When set to zero the first request will
2916 cause spawning of the first child process to handle it.
2918 Starting too few children temporary slows Squid under load while it
2919 tries to spawn enough additional processes to cope with traffic.
2923 Sets a minimum of how many processes Squid is to try and keep available
2924 at all times. When traffic begins to rise above what the existing
2925 processes can handle this many more will be spawned up to the maximum
2926 configured. A minimum setting of 1 is required.
2930 The number of requests each certificate validator helper can handle in
2931 parallel. A value of 0 indicates the certficate validator does not
2932 support concurrency. Defaults to 1.
2934 When this directive is set to a value >= 1 then the protocol
2935 used to communicate with the helper is modified to include
2936 a request ID in front of the request/response. The request
2937 ID from the request must be echoed back with the response
2942 Sets the maximum number of queued requests.
2943 If the queued requests exceed queue size for more than 3 minutes
2944 squid aborts its operation.
2945 The default value is set to 2*numberofchildren.
2947 You must have at least one ssl_crt_validator process.
2951 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2952 -----------------------------------------------------------------------------
2960 To specify other caches in a hierarchy, use the format:
2962 cache_peer hostname type http-port icp-port [options]
2967 # hostname type port port options
2968 # -------------------- -------- ----- ----- -----------
2969 cache_peer parent.foo.net parent 3128 3130 default
2970 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2971 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2972 cache_peer example.com parent 80 0 default
2973 cache_peer cdn.example.com sibling 3128 0
2975 type: either 'parent', 'sibling', or 'multicast'.
2977 proxy-port: The port number where the peer accept HTTP requests.
2978 For other Squid proxies this is usually 3128
2979 For web servers this is usually 80
2981 icp-port: Used for querying neighbor caches about objects.
2982 Set to 0 if the peer does not support ICP or HTCP.
2983 See ICP and HTCP options below for additional details.
2986 ==== ICP OPTIONS ====
2988 You MUST also set icp_port and icp_access explicitly when using these options.
2989 The defaults will prevent peer traffic using ICP.
2992 no-query Disable ICP queries to this neighbor.
2995 Indicates the named peer is a member of a multicast group.
2996 ICP queries will not be sent directly to the peer, but ICP
2997 replies will be accepted from it.
2999 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
3000 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
3003 To only send ICP queries to this neighbor infrequently.
3004 This is used to keep the neighbor round trip time updated
3005 and is usually used in conjunction with weighted-round-robin.
3008 ==== HTCP OPTIONS ====
3010 You MUST also set htcp_port and htcp_access explicitly when using these options.
3011 The defaults will prevent peer traffic using HTCP.
3014 htcp Send HTCP, instead of ICP, queries to the neighbor.
3015 You probably also want to set the "icp-port" to 4827
3016 instead of 3130. This directive accepts a comma separated
3017 list of options described below.
3019 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
3021 htcp=no-clr Send HTCP to the neighbor but without
3022 sending any CLR requests. This cannot be used with
3025 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
3026 This cannot be used with no-clr.
3029 Send HTCP to the neighbor including CLRs but only when
3030 they do not result from PURGE requests.
3033 Forward any HTCP CLR requests this proxy receives to the peer.
3036 ==== PEER SELECTION METHODS ====
3038 The default peer selection method is ICP, with the first responding peer
3039 being used as source. These options can be used for better load balancing.
3042 default This is a parent cache which can be used as a "last-resort"
3043 if a peer cannot be located by any of the peer-selection methods.
3044 If specified more than once, only the first is used.
3046 round-robin Load-Balance parents which should be used in a round-robin
3047 fashion in the absence of any ICP queries.
3048 weight=N can be used to add bias.
3050 weighted-round-robin
3051 Load-Balance parents which should be used in a round-robin
3052 fashion with the frequency of each parent being based on the
3053 round trip time. Closer parents are used more often.
3054 Usually used for background-ping parents.
3055 weight=N can be used to add bias.
3057 carp Load-Balance parents which should be used as a CARP array.
3058 The requests will be distributed among the parents based on the
3059 CARP load balancing hash function based on their weight.
3061 userhash Load-balance parents based on the client proxy_auth or ident username.
3063 sourcehash Load-balance parents based on the client source IP.
3066 To be used only for cache peers of type "multicast".
3067 ALL members of this multicast group have "sibling"
3068 relationship with it, not "parent". This is to a multicast
3069 group when the requested object would be fetched only from
3070 a "parent" cache, anyway. It's useful, e.g., when
3071 configuring a pool of redundant Squid proxies, being
3072 members of the same multicast group.
3075 ==== PEER SELECTION OPTIONS ====
3077 weight=N use to affect the selection of a peer during any weighted
3078 peer-selection mechanisms.
3079 The weight must be an integer; default is 1,
3080 larger weights are favored more.
3081 This option does not affect parent selection if a peering
3082 protocol is not in use.
3084 basetime=N Specify a base amount to be subtracted from round trip
3086 It is subtracted before division by weight in calculating
3087 which parent to fectch from. If the rtt is less than the
3088 base time the rtt is set to a minimal value.
3090 ttl=N Specify a TTL to use when sending multicast ICP queries
3092 Only useful when sending to a multicast group.
3093 Because we don't accept ICP replies from random
3094 hosts, you must configure other group members as
3095 peers with the 'multicast-responder' option.
3097 no-delay To prevent access to this neighbor from influencing the
3100 digest-url=URL Tell Squid to fetch the cache digest (if digests are
3101 enabled) for this host from the specified URL rather
3102 than the Squid default location.
3105 ==== CARP OPTIONS ====
3107 carp-key=key-specification
3108 use a different key than the full URL to hash against the peer.
3109 the key-specification is a comma-separated list of the keywords
3110 scheme, host, port, path, params
3111 Order is not important.
3113 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
3115 originserver Causes this parent to be contacted as an origin server.
3116 Meant to be used in accelerator setups when the peer
3120 Set the Host header of requests forwarded to this peer.
3121 Useful in accelerator setups where the server (peer)
3122 expects a certain domain name but clients may request
3123 others. ie example.com or www.example.com
3125 no-digest Disable request of cache digests.
3128 Disables requesting ICMP RTT database (NetDB).
3131 ==== AUTHENTICATION OPTIONS ====
3134 If this is a personal/workgroup proxy and your parent
3135 requires proxy authentication.
3137 Note: The string can include URL escapes (i.e. %20 for
3138 spaces). This also means % must be written as %%.
3141 Send login details received from client to this peer.
3142 Both Proxy- and WWW-Authorization headers are passed
3143 without alteration to the peer.
3144 Authentication is not required by Squid for this to work.
3146 Note: This will pass any form of authentication but
3147 only Basic auth will work through a proxy unless the
3148 connection-auth options are also used.
3150 login=PASS Send login details received from client to this peer.
3151 Authentication is not required by this option.
3153 If there are no client-provided authentication headers
3154 to pass on, but username and password are available
3155 from an external ACL user= and password= result tags
3156 they may be sent instead.
3158 Note: To combine this with proxy_auth both proxies must
3159 share the same user database as HTTP only allows for
3160 a single login (one for proxy, one for origin server).
3161 Also be warned this will expose your users proxy
3162 password to the peer. USE WITH CAUTION
3165 Send the username to the upstream cache, but with a
3166 fixed password. This is meant to be used when the peer
3167 is in another administrative domain, but it is still
3168 needed to identify each user.
3169 The star can optionally be followed by some extra
3170 information which is added to the username. This can
3171 be used to identify this proxy to the peer, similar to
3172 the login=username:password option above.
3175 If this is a personal/workgroup proxy and your parent
3176 requires a secure proxy authentication.
3177 The first principal from the default keytab or defined by
3178 the environment variable KRB5_KTNAME will be used.
3180 WARNING: The connection may transmit requests from multiple
3181 clients. Negotiate often assumes end-to-end authentication
3182 and a single-client. Which is not strictly true here.
3184 login=NEGOTIATE:principal_name
3185 If this is a personal/workgroup proxy and your parent
3186 requires a secure proxy authentication.
3187 The principal principal_name from the default keytab or
3188 defined by the environment variable KRB5_KTNAME will be
3191 WARNING: The connection may transmit requests from multiple
3192 clients. Negotiate often assumes end-to-end authentication
3193 and a single-client. Which is not strictly true here.
3195 connection-auth=on|off
3196 Tell Squid that this peer does or not support Microsoft
3197 connection oriented authentication, and any such
3198 challenges received from there should be ignored.
3199 Default is auto to automatically determine the status
3203 ==== SSL / HTTPS / TLS OPTIONS ====
3205 ssl Encrypt connections to this peer with SSL/TLS.
3207 sslcert=/path/to/ssl/certificate
3208 A client SSL certificate to use when connecting to
3211 sslkey=/path/to/ssl/key
3212 The private SSL key corresponding to sslcert above.
3213 If 'sslkey' is not specified 'sslcert' is assumed to
3214 reference a combined file containing both the
3215 certificate and the key.
3217 sslcipher=... The list of valid SSL ciphers to use when connecting
3221 The minimum TLS protocol version to permit. To control
3222 SSLv3 use the ssloptions= parameter.
3223 Supported Values: 1.0 (default), 1.1, 1.2
3225 ssloptions=... Specify various SSL implementation options:
3227 NO_SSLv3 Disallow the use of SSLv3
3229 NO_TLSv1 Disallow the use of TLSv1.0
3231 NO_TLSv1_1 Disallow the use of TLSv1.1
3233 NO_TLSv1_2 Disallow the use of TLSv1.2
3236 Always create a new key when using
3237 temporary/ephemeral DH key exchanges
3240 Disable use of RFC5077 session tickets.
3241 Some servers may have problems
3242 understanding the TLS extension due
3243 to ambiguous specification in RFC4507.
3245 ALL Enable various bug workarounds
3246 suggested as "harmless" by OpenSSL
3247 Be warned that this reduces SSL/TLS
3248 strength to some attacks.
3250 See the OpenSSL SSL_CTX_set_options documentation for a
3253 tls-cafile= PEM file containing CA certificates to use when verifying
3254 the peer certificate. May be repeated to load multiple files.
3256 sslcapath=... A directory containing additional CA certificates to
3257 use when verifying the peer certificate.
3258 Requires OpenSSL or LibreSSL.
3260 sslcrlfile=... A certificate revocation list file to use when
3261 verifying the peer certificate.
3263 sslflags=... Specify various flags modifying the SSL implementation:
3266 Accept certificates even if they fail to
3270 Don't verify the peer certificate
3271 matches the server name
3273 ssldomain= The peer name as advertised in it's certificate.
3274 Used for verifying the correctness of the received peer
3275 certificate. If not specified the peer hostname will be
3279 Enable the "Front-End-Https: On" header needed when
3280 using Squid as a SSL frontend in front of Microsoft OWA.
3281 See MS KB document Q307347 for details on this header.
3282 If set to auto the header will only be added if the
3283 request is forwarded as a https:// URL.
3286 Do not use the system default Trusted CA.
3288 tls-no-npn Do not use the TLS NPN extension to advertise HTTP/1.1.
3290 ==== GENERAL OPTIONS ====
3293 A peer-specific connect timeout.
3294 Also see the peer_connect_timeout directive.
3296 connect-fail-limit=N
3297 How many times connecting to a peer must fail before
3298 it is marked as down. Standby connection failures
3299 count towards this limit. Default is 10.
3301 allow-miss Disable Squid's use of only-if-cached when forwarding
3302 requests to siblings. This is primarily useful when
3303 icp_hit_stale is used by the sibling. Excessive use
3304 of this option may result in forwarding loops. One way
3305 to prevent peering loops when using this option, is to
3306 deny cache peer usage on requests from a peer:
3308 cache_peer_access peerName deny fromPeer
3310 max-conn=N Limit the number of concurrent connections the Squid
3311 may open to this peer, including already opened idle
3312 and standby connections. There is no peer-specific
3313 connection limit by default.
3315 A peer exceeding the limit is not used for new
3316 requests unless a standby connection is available.
3318 max-conn currently works poorly with idle persistent
3319 connections: When a peer reaches its max-conn limit,
3320 and there are idle persistent connections to the peer,
3321 the peer may not be selected because the limiting code
3322 does not know whether Squid can reuse those idle
3325 standby=N Maintain a pool of N "hot standby" connections to an
3326 UP peer, available for requests when no idle
3327 persistent connection is available (or safe) to use.
3328 By default and with zero N, no such pool is maintained.
3329 N must not exceed the max-conn limit (if any).
3331 At start or after reconfiguration, Squid opens new TCP
3332 standby connections until there are N connections
3333 available and then replenishes the standby pool as
3334 opened connections are used up for requests. A used
3335 connection never goes back to the standby pool, but
3336 may go to the regular idle persistent connection pool
3337 shared by all peers and origin servers.
3339 Squid never opens multiple new standby connections
3340 concurrently. This one-at-a-time approach minimizes
3341 flooding-like effect on peers. Furthermore, just a few
3342 standby connections should be sufficient in most cases
3343 to supply most new requests with a ready-to-use
3346 Standby connections obey server_idle_pconn_timeout.
3347 For the feature to work as intended, the peer must be
3348 configured to accept and keep them open longer than
3349 the idle timeout at the connecting Squid, to minimize
3350 race conditions typical to idle used persistent
3351 connections. Default request_timeout and
3352 server_idle_pconn_timeout values ensure such a
3355 name=xxx Unique name for the peer.
3356 Required if you have multiple peers on the same host
3357 but different ports.
3358 This name can be used in cache_peer_access and similar
3359 directives to identify the peer.
3360 Can be used by outgoing access controls through the
3363 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3364 requests to this peer. Use normal address selection instead.
3365 This overrides the spoof_client_ip ACL.
3367 proxy-only objects fetched from the peer will not be stored locally.
3371 NAME: cache_peer_access
3374 DEFAULT_DOC: No peer usage restrictions.
3377 Restricts usage of cache_peer proxies.
3380 cache_peer_access peer-name allow|deny [!]aclname ...
3382 For the required peer-name parameter, use either the value of the
3383 cache_peer name=value parameter or, if name=value is missing, the
3384 cache_peer hostname parameter.
3386 This directive narrows down the selection of peering candidates, but
3387 does not determine the order in which the selected candidates are
3388 contacted. That order is determined by the peer selection algorithms
3389 (see PEER SELECTION sections in the cache_peer documentation).
3391 If a deny rule matches, the corresponding peer will not be contacted
3392 for the current transaction -- Squid will not send ICP queries and
3393 will not forward HTTP requests to that peer. An allow match leaves
3394 the corresponding peer in the selection. The first match for a given
3395 peer wins for that peer.
3397 The relative order of cache_peer_access directives for the same peer
3398 matters. The relative order of any two cache_peer_access directives
3399 for different peers does not matter. To ease interpretation, it is a
3400 good idea to group cache_peer_access directives for the same peer
3403 A single cache_peer_access directive may be evaluated multiple times
3404 for a given transaction because individual peer selection algorithms
3405 may check it independently from each other. These redundant checks
3406 may be optimized away in future Squid versions.
3408 This clause only supports fast acl types.
3409 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3413 NAME: neighbor_type_domain
3414 TYPE: hostdomaintype
3416 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3419 Modify the cache_peer neighbor type when passing requests
3420 about specific domains to the peer.
3423 neighbor_type_domain neighbor parent|sibling domain domain ...
3426 cache_peer foo.example.com parent 3128 3130
3427 neighbor_type_domain foo.example.com sibling .au .de
3429 The above configuration treats all requests to foo.example.com as a
3430 parent proxy unless the request is for a .au or .de ccTLD domain name.
3433 NAME: dead_peer_timeout
3437 LOC: Config.Timeout.deadPeer
3439 This controls how long Squid waits to declare a peer cache
3440 as "dead." If there are no ICP replies received in this
3441 amount of time, Squid will declare the peer dead and not
3442 expect to receive any further ICP replies. However, it
3443 continues to send ICP queries, and will mark the peer as
3444 alive upon receipt of the first subsequent ICP reply.
3446 This timeout also affects when Squid expects to receive ICP
3447 replies from peers. If more than 'dead_peer' seconds have
3448 passed since the last ICP reply was received, Squid will not
3449 expect to receive an ICP reply on the next query. Thus, if
3450 your time between requests is greater than this timeout, you
3451 will see a lot of requests sent DIRECT to origin servers
3452 instead of to your parents.
3455 NAME: forward_max_tries
3458 LOC: Config.forward_max_tries
3460 Controls how many different forward paths Squid will try
3461 before giving up. See also forward_timeout.
3463 NOTE: connect_retries (default: none) can make each of these
3464 possible forwarding paths be tried multiple times.
3468 MEMORY CACHE OPTIONS
3469 -----------------------------------------------------------------------------
3476 LOC: Config.memMaxSize
3478 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3479 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3480 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3481 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3483 'cache_mem' specifies the ideal amount of memory to be used
3485 * In-Transit objects
3487 * Negative-Cached objects
3489 Data for these objects are stored in 4 KB blocks. This
3490 parameter specifies the ideal upper limit on the total size of
3491 4 KB blocks allocated. In-Transit objects take the highest
3494 In-transit objects have priority over the others. When
3495 additional space is needed for incoming data, negative-cached
3496 and hot objects will be released. In other words, the
3497 negative-cached and hot objects will fill up any unused space
3498 not needed for in-transit objects.
3500 If circumstances require, this limit will be exceeded.
3501 Specifically, if your incoming request rate requires more than
3502 'cache_mem' of memory to hold in-transit objects, Squid will
3503 exceed this limit to satisfy the new requests. When the load
3504 decreases, blocks will be freed until the high-water mark is
3505 reached. Thereafter, blocks will be used to store hot
3508 If shared memory caching is enabled, Squid does not use the shared
3509 cache space for in-transit objects, but they still consume as much
3510 local memory as they need. For more details about the shared memory
3511 cache, see memory_cache_shared.
3514 NAME: maximum_object_size_in_memory
3518 LOC: Config.Store.maxInMemObjSize
3520 Objects greater than this size will not be attempted to kept in
3521 the memory cache. This should be set high enough to keep objects
3522 accessed frequently in memory to improve performance whilst low
3523 enough to keep larger objects from hoarding cache_mem.
3526 NAME: memory_cache_shared
3529 LOC: Config.memShared
3531 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3533 Controls whether the memory cache is shared among SMP workers.
3535 The shared memory cache is meant to occupy cache_mem bytes and replace
3536 the non-shared memory cache, although some entities may still be
3537 cached locally by workers for now (e.g., internal and in-transit
3538 objects may be served from a local memory cache even if shared memory
3539 caching is enabled).
3541 By default, the memory cache is shared if and only if all of the
3542 following conditions are satisfied: Squid runs in SMP mode with
3543 multiple workers, cache_mem is positive, and Squid environment
3544 supports required IPC primitives (e.g., POSIX shared memory segments
3545 and GCC-style atomic operations).
3547 To avoid blocking locks, shared memory uses opportunistic algorithms
3548 that do not guarantee that every cachable entity that could have been
3549 shared among SMP workers will actually be shared.
3551 Currently, entities exceeding 32KB in size cannot be shared.
3554 NAME: memory_cache_mode
3558 DEFAULT_DOC: Keep the most recently fetched objects in memory
3560 Controls which objects to keep in the memory cache (cache_mem)
3562 always Keep most recently fetched objects in memory (default)
3564 disk Only disk cache hits are kept in memory, which means
3565 an object must first be cached on disk and then hit
3566 a second time before cached in memory.
3568 network Only objects fetched from network is kept in memory
3571 NAME: memory_replacement_policy
3573 LOC: Config.memPolicy
3576 The memory replacement policy parameter determines which
3577 objects are purged from memory when memory space is needed.
3579 See cache_replacement_policy for details on algorithms.
3584 -----------------------------------------------------------------------------
3587 NAME: cache_replacement_policy
3589 LOC: Config.replPolicy
3592 The cache replacement policy parameter determines which
3593 objects are evicted (replaced) when disk space is needed.
3595 lru : Squid's original list based LRU policy
3596 heap GDSF : Greedy-Dual Size Frequency
3597 heap LFUDA: Least Frequently Used with Dynamic Aging
3598 heap LRU : LRU policy implemented using a heap
3600 Applies to any cache_dir lines listed below this directive.
3602 The LRU policies keeps recently referenced objects.
3604 The heap GDSF policy optimizes object hit rate by keeping smaller
3605 popular objects in cache so it has a better chance of getting a
3606 hit. It achieves a lower byte hit rate than LFUDA though since
3607 it evicts larger (possibly popular) objects.
3609 The heap LFUDA policy keeps popular objects in cache regardless of
3610 their size and thus optimizes byte hit rate at the expense of
3611 hit rate since one large, popular object will prevent many
3612 smaller, slightly less popular objects from being cached.
3614 Both policies utilize a dynamic aging mechanism that prevents
3615 cache pollution that can otherwise occur with frequency-based
3616 replacement policies.
3618 NOTE: if using the LFUDA replacement policy you should increase
3619 the value of maximum_object_size above its default of 4 MB to
3620 to maximize the potential byte hit rate improvement of LFUDA.
3622 For more information about the GDSF and LFUDA cache replacement
3623 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3624 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3627 NAME: minimum_object_size
3631 DEFAULT_DOC: no limit
3632 LOC: Config.Store.minObjectSize
3634 Objects smaller than this size will NOT be saved on disk. The
3635 value is specified in bytes, and the default is 0 KB, which
3636 means all responses can be stored.
3639 NAME: maximum_object_size
3643 LOC: Config.Store.maxObjectSize
3645 Set the default value for max-size parameter on any cache_dir.
3646 The value is specified in bytes, and the default is 4 MB.
3648 If you wish to get a high BYTES hit ratio, you should probably
3649 increase this (one 32 MB object hit counts for 3200 10KB
3652 If you wish to increase hit ratio more than you want to
3653 save bandwidth you should leave this low.
3655 NOTE: if using the LFUDA replacement policy you should increase
3656 this value to maximize the byte hit rate improvement of LFUDA!
3657 See cache_replacement_policy for a discussion of this policy.
3663 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3664 LOC: Config.cacheSwap
3667 cache_dir Type Directory-Name Fs-specific-data [options]
3669 You can specify multiple cache_dir lines to spread the
3670 cache among different disk partitions.
3672 Type specifies the kind of storage system to use. Only "ufs"
3673 is built by default. To enable any of the other storage systems
3674 see the --enable-storeio configure option.
3676 'Directory' is a top-level directory where cache swap
3677 files will be stored. If you want to use an entire disk
3678 for caching, this can be the mount-point directory.
3679 The directory must exist and be writable by the Squid
3680 process. Squid will NOT create this directory for you.
3682 In SMP configurations, cache_dir must not precede the workers option
3683 and should use configuration macros or conditionals to give each
3684 worker interested in disk caching a dedicated cache directory.
3687 ==== The ufs store type ====
3689 "ufs" is the old well-known Squid storage format that has always
3693 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3695 'Mbytes' is the amount of disk space (MB) to use under this
3696 directory. The default is 100 MB. Change this to suit your
3697 configuration. Do NOT put the size of your disk drive here.
3698 Instead, if you want Squid to use the entire disk drive,
3699 subtract 20% and use that value.
3701 'L1' is the number of first-level subdirectories which
3702 will be created under the 'Directory'. The default is 16.
3704 'L2' is the number of second-level subdirectories which
3705 will be created under each first-level directory. The default
3709 ==== The aufs store type ====
3711 "aufs" uses the same storage format as "ufs", utilizing
3712 POSIX-threads to avoid blocking the main Squid process on
3713 disk-I/O. This was formerly known in Squid as async-io.
3716 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3718 see argument descriptions under ufs above
3721 ==== The diskd store type ====
3723 "diskd" uses the same storage format as "ufs", utilizing a
3724 separate process to avoid blocking the main Squid process on
3728 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3730 see argument descriptions under ufs above
3732 Q1 specifies the number of unacknowledged I/O requests when Squid
3733 stops opening new files. If this many messages are in the queues,
3734 Squid won't open new files. Default is 64
3736 Q2 specifies the number of unacknowledged messages when Squid
3737 starts blocking. If this many messages are in the queues,
3738 Squid blocks until it receives some replies. Default is 72
3740 When Q1 < Q2 (the default), the cache directory is optimized
3741 for lower response time at the expense of a decrease in hit
3742 ratio. If Q1 > Q2, the cache directory is optimized for
3743 higher hit ratio at the expense of an increase in response
3747 ==== The rock store type ====
3750 cache_dir rock Directory-Name Mbytes [options]
3752 The Rock Store type is a database-style storage. All cached
3753 entries are stored in a "database" file, using fixed-size slots.
3754 A single entry occupies one or more slots.
3756 If possible, Squid using Rock Store creates a dedicated kid
3757 process called "disker" to avoid blocking Squid worker(s) on disk
3758 I/O. One disker kid is created for each rock cache_dir. Diskers
3759 are created only when Squid, running in daemon mode, has support
3760 for the IpcIo disk I/O module.
3762 swap-timeout=msec: Squid will not start writing a miss to or
3763 reading a hit from disk if it estimates that the swap operation
3764 will take more than the specified number of milliseconds. By
3765 default and when set to zero, disables the disk I/O time limit
3766 enforcement. Ignored when using blocking I/O module because
3767 blocking synchronous I/O does not allow Squid to estimate the
3768 expected swap wait time.
3770 max-swap-rate=swaps/sec: Artificially limits disk access using
3771 the specified I/O rate limit. Swap out requests that
3772 would cause the average I/O rate to exceed the limit are
3773 delayed. Individual swap in requests (i.e., hits or reads) are
3774 not delayed, but they do contribute to measured swap rate and
3775 since they are placed in the same FIFO queue as swap out
3776 requests, they may wait longer if max-swap-rate is smaller.
3777 This is necessary on file systems that buffer "too
3778 many" writes and then start blocking Squid and other processes
3779 while committing those writes to disk. Usually used together
3780 with swap-timeout to avoid excessive delays and queue overflows
3781 when disk demand exceeds available disk "bandwidth". By default
3782 and when set to zero, disables the disk I/O rate limit
3783 enforcement. Currently supported by IpcIo module only.
3785 slot-size=bytes: The size of a database "record" used for
3786 storing cached responses. A cached response occupies at least
3787 one slot and all database I/O is done using individual slots so
3788 increasing this parameter leads to more disk space waste while
3789 decreasing it leads to more disk I/O overheads. Should be a
3790 multiple of your operating system I/O page size. Defaults to
3791 16KBytes. A housekeeping header is stored with each slot and
3792 smaller slot-sizes will be rejected. The header is smaller than
3796 ==== COMMON OPTIONS ====
3798 no-store no new objects should be stored to this cache_dir.
3800 min-size=n the minimum object size in bytes this cache_dir
3801 will accept. It's used to restrict a cache_dir
3802 to only store large objects (e.g. AUFS) while
3803 other stores are optimized for smaller objects
3807 max-size=n the maximum object size in bytes this cache_dir
3809 The value in maximum_object_size directive sets
3810 the default unless more specific details are
3811 available (ie a small store capacity).
3813 Note: To make optimal use of the max-size limits you should order
3814 the cache_dir lines with the smallest max-size value first.
3818 # Uncomment and adjust the following to add a disk cache directory.
3819 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3823 NAME: store_dir_select_algorithm
3825 LOC: Config.store_dir_select_algorithm
3828 How Squid selects which cache_dir to use when the response
3829 object will fit into more than one.
3831 Regardless of which algorithm is used the cache_dir min-size
3832 and max-size parameters are obeyed. As such they can affect
3833 the selection algorithm by limiting the set of considered
3840 This algorithm is suited to caches with similar cache_dir
3841 sizes and disk speeds.
3843 The disk with the least I/O pending is selected.
3844 When there are multiple disks with the same I/O load ranking
3845 the cache_dir with most available capacity is selected.
3847 When a mix of cache_dir sizes are configured the faster disks
3848 have a naturally lower I/O loading and larger disks have more
3849 capacity. So space used to store objects and data throughput
3850 may be very unbalanced towards larger disks.
3855 This algorithm is suited to caches with unequal cache_dir
3858 Each cache_dir is selected in a rotation. The next suitable
3861 Available cache_dir capacity is only considered in relation
3862 to whether the object will fit and meets the min-size and
3863 max-size parameters.
3865 Disk I/O loading is only considered to prevent overload on slow
3866 disks. This algorithm does not spread objects by size, so any
3867 I/O loading per-disk may appear very unbalanced and volatile.
3869 If several cache_dirs use similar min-size, max-size, or other
3870 limits to to reject certain responses, then do not group such
3871 cache_dir lines together, to avoid round-robin selection bias
3872 towards the first cache_dir after the group. Instead, interleave
3873 cache_dir lines from different groups. For example:
3875 store_dir_select_algorithm round-robin
3876 cache_dir rock /hdd1 ... min-size=100000
3877 cache_dir rock /ssd1 ... max-size=99999
3878 cache_dir rock /hdd2 ... min-size=100000
3879 cache_dir rock /ssd2 ... max-size=99999
3880 cache_dir rock /hdd3 ... min-size=100000
3881 cache_dir rock /ssd3 ... max-size=99999
3884 NAME: max_open_disk_fds
3886 LOC: Config.max_open_disk_fds
3888 DEFAULT_DOC: no limit
3890 To avoid having disk as the I/O bottleneck Squid can optionally
3891 bypass the on-disk cache if more than this amount of disk file
3892 descriptors are open.
3894 A value of 0 indicates no limit.
3897 NAME: cache_swap_low
3898 COMMENT: (percent, 0-100)
3901 LOC: Config.Swap.lowWaterMark
3903 The low-water mark for AUFS/UFS/diskd cache object eviction by
3904 the cache_replacement_policy algorithm.
3906 Removal begins when the swap (disk) usage of a cache_dir is
3907 above this low-water mark and attempts to maintain utilization
3908 near the low-water mark.
3910 As swap utilization increases towards the high-water mark set
3911 by cache_swap_high object eviction becomes more agressive.
3913 The value difference in percentages between low- and high-water
3914 marks represent an eviction rate of 300 objects per second and
3915 the rate continues to scale in agressiveness by multiples of
3916 this above the high-water mark.
3918 Defaults are 90% and 95%. If you have a large cache, 5% could be
3919 hundreds of MB. If this is the case you may wish to set these
3920 numbers closer together.
3922 See also cache_swap_high and cache_replacement_policy
3925 NAME: cache_swap_high
3926 COMMENT: (percent, 0-100)
3929 LOC: Config.Swap.highWaterMark
3931 The high-water mark for AUFS/UFS/diskd cache object eviction by
3932 the cache_replacement_policy algorithm.
3934 Removal begins when the swap (disk) usage of a cache_dir is
3935 above the low-water mark set by cache_swap_low and attempts to
3936 maintain utilization near the low-water mark.
3938 As swap utilization increases towards this high-water mark object
3939 eviction becomes more agressive.
3941 The value difference in percentages between low- and high-water
3942 marks represent an eviction rate of 300 objects per second and
3943 the rate continues to scale in agressiveness by multiples of
3944 this above the high-water mark.
3946 Defaults are 90% and 95%. If you have a large cache, 5% could be
3947 hundreds of MB. If this is the case you may wish to set these
3948 numbers closer together.
3950 See also cache_swap_low and cache_replacement_policy
3955 -----------------------------------------------------------------------------
3962 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
3966 logformat <name> <format specification>
3968 Defines an access log format.
3970 The <format specification> is a string with embedded % format codes
3972 % format codes all follow the same basic structure where all but
3973 the formatcode is optional. Output strings are automatically escaped
3974 as required according to their context and the output format
3975 modifiers are usually not needed, but can be specified if an explicit
3976 output format is desired.
3978 % ["|[|'|#|/] [-] [[0]width] [{arg}] formatcode [{arg}]
3980 " output in quoted string format
3981 [ output in squid text log format as used by log_mime_hdrs
3982 # output in URL quoted format
3983 / output in shell \-escaped format
3988 width minimum and/or maximum field width:
3989 [width_min][.width_max]
3990 When minimum starts with 0, the field is zero-padded.
3991 String values exceeding maximum width are truncated.
3993 {arg} argument such as header name etc. This field may be
3994 placed before or after the token, but not both at once.
3998 % a literal % character
3999 sn Unique sequence number per log line entry
4000 err_code The ID of an error response served by Squid or
4001 a similar internal error identifier.
4002 err_detail Additional err_code-dependent error information.
4003 note The annotation specified by the argument. Also
4004 logs the adaptation meta headers set by the
4005 adaptation_meta configuration parameter.
4006 If no argument given all annotations logged.
4007 The argument may include a separator to use with
4010 By default, multiple note values are separated with ","
4011 and multiple notes are separated with "\r\n".
4012 When logging named notes with %{name}note, the
4013 explicitly configured separator is used between note
4014 values. When logging all notes with %note, the
4015 explicitly configured separator is used between
4016 individual notes. There is currently no way to
4017 specify both value and notes separators when logging
4018 all notes with %note.
4020 Connection related format codes:
4022 >a Client source IP address
4024 >p Client source port
4025 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
4026 >la Local IP address the client connected to
4027 >lp Local port number the client connected to
4028 >qos Client connection TOS/DSCP value set by Squid
4029 >nfmark Client connection netfilter mark set by Squid
4031 la Local listening IP address the client connection was connected to.
4032 lp Local listening port number the client connection was connected to.
4034 <a Server IP address of the last server or peer connection
4035 <A Server FQDN or peer name
4036 <p Server port number of the last server or peer connection
4037 <la Local IP address of the last server or peer connection
4038 <lp Local port number of the last server or peer connection
4039 <qos Server connection TOS/DSCP value set by Squid
4040 <nfmark Server connection netfilter mark set by Squid
4042 Time related format codes:
4044 ts Seconds since epoch
4045 tu subsecond time (milliseconds)
4046 tl Local time. Optional strftime format argument
4047 default %d/%b/%Y:%H:%M:%S %z
4048 tg GMT time. Optional strftime format argument
4049 default %d/%b/%Y:%H:%M:%S %z
4050 tr Response time (milliseconds)
4051 dt Total time spent making DNS lookups (milliseconds)
4052 tS Approximate master transaction start time in
4053 <full seconds since epoch>.<fractional seconds> format.
4054 Currently, Squid considers the master transaction
4055 started when a complete HTTP request header initiating
4056 the transaction is received from the client. This is
4057 the same value that Squid uses to calculate transaction
4058 response time when logging %tr to access.log. Currently,
4059 Squid uses millisecond resolution for %tS values,
4060 similar to the default access.log "current time" field
4063 Access Control related format codes:
4065 et Tag returned by external acl
4066 ea Log string returned by external acl
4067 un User name (any available)
4068 ul User name from authentication
4069 ue User name from external acl helper
4070 ui User name from ident
4071 un A user name. Expands to the first available name
4072 from the following list of information sources:
4073 - authenticated user name, like %ul
4074 - user name supplied by an external ACL, like %ue
4075 - SSL client name, like %us
4076 - ident user name, like %ui
4077 credentials Client credentials. The exact meaning depends on
4078 the authentication scheme: For Basic authentication,
4079 it is the password; for Digest, the realm sent by the
4080 client; for NTLM and Negotiate, the client challenge
4081 or client credentials prefixed with "YR " or "KK ".
4083 HTTP related format codes:
4087 [http::]rm Request method (GET/POST etc)
4088 [http::]>rm Request method from client
4089 [http::]<rm Request method sent to server or peer
4090 [http::]ru Request URL from client (historic, filtered for logging)
4091 [http::]>ru Request URL from client
4092 [http::]<ru Request URL sent to server or peer
4093 [http::]>rs Request URL scheme from client
4094 [http::]<rs Request URL scheme sent to server or peer
4095 [http::]>rd Request URL domain from client
4096 [http::]<rd Request URL domain sent to server or peer
4097 [http::]>rP Request URL port from client
4098 [http::]<rP Request URL port sent to server or peer
4099 [http::]rp Request URL path excluding hostname
4100 [http::]>rp Request URL path excluding hostname from client
4101 [http::]<rp Request URL path excluding hostname sent to server or peer
4102 [http::]rv Request protocol version
4103 [http::]>rv Request protocol version from client
4104 [http::]<rv Request protocol version sent to server or peer
4106 [http::]>h Original received request header.
4107 Usually differs from the request header sent by
4108 Squid, although most fields are often preserved.
4109 Accepts optional header field name/value filter
4110 argument using name[:[separator]element] format.
4111 [http::]>ha Received request header after adaptation and
4112 redirection (pre-cache REQMOD vectoring point).
4113 Usually differs from the request header sent by
4114 Squid, although most fields are often preserved.
4115 Optional header name argument as for >h
4119 [http::]<Hs HTTP status code received from the next hop
4120 [http::]>Hs HTTP status code sent to the client
4122 [http::]<h Reply header. Optional header name argument
4125 [http::]mt MIME content type
4130 [http::]st Total size of request + reply traffic with client
4131 [http::]>st Total size of request received from client.
4132 Excluding chunked encoding bytes.
4133 [http::]<st Total size of reply sent to client (after adaptation)
4135 [http::]>sh Size of request headers received from client
4136 [http::]<sh Size of reply headers sent to client (after adaptation)
4138 [http::]<sH Reply high offset sent
4139 [http::]<sS Upstream object size
4141 [http::]<bs Number of HTTP-equivalent message body bytes
4142 received from the next hop, excluding chunked
4143 transfer encoding and control messages.
4144 Generated FTP/Gopher listings are treated as
4149 [http::]<pt Peer response time in milliseconds. The timer starts
4150 when the last request byte is sent to the next hop
4151 and stops when the last response byte is received.
4152 [http::]<tt Total time in milliseconds. The timer
4153 starts with the first connect request (or write I/O)
4154 sent to the first selected peer. The timer stops
4155 with the last I/O with the last peer.
4157 Squid handling related format codes:
4159 Ss Squid request status (TCP_MISS etc)
4160 Sh Squid hierarchy status (DEFAULT_PARENT etc)
4162 SSL-related format codes:
4164 ssl::bump_mode SslBump decision for the transaction:
4166 For CONNECT requests that initiated bumping of
4167 a connection and for any request received on
4168 an already bumped connection, Squid logs the
4169 corresponding SslBump mode ("server-first" or
4170 "client-first"). See the ssl_bump option for
4171 more information about these modes.
4173 A "none" token is logged for requests that
4174 triggered "ssl_bump" ACL evaluation matching
4175 either a "none" rule or no rules at all.
4177 In all other cases, a single dash ("-") is
4180 ssl::>sni SSL client SNI sent to Squid. Available only
4181 after the peek, stare, or splice SSL bumping
4185 The Subject field of the received client
4186 SSL certificate or a dash ('-') if Squid has
4187 received an invalid/malformed certificate or
4188 no certificate at all. Consider encoding the
4189 logged value because Subject often has spaces.
4192 The Issuer field of the received client
4193 SSL certificate or a dash ('-') if Squid has
4194 received an invalid/malformed certificate or
4195 no certificate at all. Consider encoding the
4196 logged value because Issuer often has spaces.
4199 The list of certificate validation errors
4200 detected by Squid (including OpenSSL and
4201 certificate validation helper components). The
4202 errors are listed in the discovery order. By
4203 default, the error codes are separated by ':'.
4204 Accepts an optional separator argument.
4206 If ICAP is enabled, the following code becomes available (as
4207 well as ICAP log codes documented with the icap_log option):
4209 icap::tt Total ICAP processing time for the HTTP
4210 transaction. The timer ticks when ICAP
4211 ACLs are checked and when ICAP
4212 transaction is in progress.
4214 If adaptation is enabled the following codes become available:
4216 adapt::<last_h The header of the last ICAP response or
4217 meta-information from the last eCAP
4218 transaction related to the HTTP transaction.
4219 Like <h, accepts an optional header name
4222 adapt::sum_trs Summed adaptation transaction response
4223 times recorded as a comma-separated list in
4224 the order of transaction start time. Each time
4225 value is recorded as an integer number,
4226 representing response time of one or more
4227 adaptation (ICAP or eCAP) transaction in
4228 milliseconds. When a failed transaction is
4229 being retried or repeated, its time is not
4230 logged individually but added to the
4231 replacement (next) transaction. See also:
4234 adapt::all_trs All adaptation transaction response times.
4235 Same as adaptation_strs but response times of
4236 individual transactions are never added
4237 together. Instead, all transaction response
4238 times are recorded individually.
4240 You can prefix adapt::*_trs format codes with adaptation
4241 service name in curly braces to record response time(s) specific
4242 to that service. For example: %{my_service}adapt::sum_trs
4244 The default formats available (which do not need re-defining) are:
4246 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
4247 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
4248 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
4249 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
4250 logformat useragent %>a [%tl] "%{User-Agent}>h"
4252 NOTE: When the log_mime_hdrs directive is set to ON.
4253 The squid, common and combined formats have a safely encoded copy
4254 of the mime headers appended to each line within a pair of brackets.
4256 NOTE: The common and combined formats are not quite true to the Apache definition.
4257 The logs from Squid contain an extra status and hierarchy code appended.
4261 NAME: access_log cache_access_log
4263 LOC: Config.Log.accesslogs
4264 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
4266 Configures whether and how Squid logs HTTP and ICP transactions.
4267 If access logging is enabled, a single line is logged for every
4268 matching HTTP or ICP request. The recommended directive formats are:
4270 access_log <module>:<place> [option ...] [acl acl ...]
4271 access_log none [acl acl ...]
4273 The following directive format is accepted but may be deprecated:
4274 access_log <module>:<place> [<logformat name> [acl acl ...]]
4276 In most cases, the first ACL name must not contain the '=' character
4277 and should not be equal to an existing logformat name. You can always
4278 start with an 'all' ACL to work around those restrictions.
4280 Will log to the specified module:place using the specified format (which
4281 must be defined in a logformat directive) those entries which match
4282 ALL the acl's specified (which must be defined in acl clauses).
4283 If no acl is specified, all requests will be logged to this destination.
4285 ===== Available options for the recommended directive format =====
4287 logformat=name Names log line format (either built-in or
4288 defined by a logformat directive). Defaults
4291 buffer-size=64KB Defines approximate buffering limit for log
4292 records (see buffered_logs). Squid should not
4293 keep more than the specified size and, hence,
4294 should flush records before the buffer becomes
4295 full to avoid overflows under normal
4296 conditions (the exact flushing algorithm is
4297 module-dependent though). The on-error option
4298 controls overflow handling.
4300 on-error=die|drop Defines action on unrecoverable errors. The
4301 'drop' action ignores (i.e., does not log)
4302 affected log records. The default 'die' action
4303 kills the affected worker. The drop action
4304 support has not been tested for modules other
4307 rotate=N Specifies the number of log file rotations to
4308 make when you run 'squid -k rotate'. The default
4309 is to obey the logfile_rotate directive. Setting
4310 rotate=0 will disable the file name rotation,
4311 but the log files are still closed and re-opened.
4312 This will enable you to rename the logfiles
4313 yourself just before sending the rotate signal.
4314 Only supported by the stdio module.
4316 ===== Modules Currently available =====
4318 none Do not log any requests matching these ACL.
4319 Do not specify Place or logformat name.
4321 stdio Write each log line to disk immediately at the completion of
4323 Place: the filename and path to be written.
4325 daemon Very similar to stdio. But instead of writing to disk the log
4326 line is passed to a daemon helper for asychronous handling instead.
4327 Place: varies depending on the daemon.
4329 log_file_daemon Place: the file name and path to be written.
4331 syslog To log each request via syslog facility.
4332 Place: The syslog facility and priority level for these entries.
4333 Place Format: facility.priority
4335 where facility could be any of:
4336 authpriv, daemon, local0 ... local7 or user.
4338 And priority could be any of:
4339 err, warning, notice, info, debug.
4341 udp To send each log line as text data to a UDP receiver.
4342 Place: The destination host name or IP and port.
4343 Place Format: //host:port
4345 tcp To send each log line as text data to a TCP receiver.
4346 Lines may be accumulated before sending (see buffered_logs).
4347 Place: The destination host name or IP and port.
4348 Place Format: //host:port
4351 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4357 LOC: Config.Log.icaplogs
4360 ICAP log files record ICAP transaction summaries, one line per
4363 The icap_log option format is:
4364 icap_log <filepath> [<logformat name> [acl acl ...]]
4365 icap_log none [acl acl ...]]
4367 Please see access_log option documentation for details. The two
4368 kinds of logs share the overall configuration approach and many
4371 ICAP processing of a single HTTP message or transaction may
4372 require multiple ICAP transactions. In such cases, multiple
4373 ICAP transaction log lines will correspond to a single access
4376 ICAP log uses logformat codes that make sense for an ICAP
4377 transaction. Header-related codes are applied to the HTTP header
4378 embedded in an ICAP server response, with the following caveats:
4379 For REQMOD, there is no HTTP response header unless the ICAP
4380 server performed request satisfaction. For RESPMOD, the HTTP
4381 request header is the header sent to the ICAP server. For
4382 OPTIONS, there are no HTTP headers.
4384 The following format codes are also available for ICAP logs:
4386 icap::<A ICAP server IP address. Similar to <A.
4388 icap::<service_name ICAP service name from the icap_service
4389 option in Squid configuration file.
4391 icap::ru ICAP Request-URI. Similar to ru.
4393 icap::rm ICAP request method (REQMOD, RESPMOD, or
4394 OPTIONS). Similar to existing rm.
4396 icap::>st Bytes sent to the ICAP server (TCP payload
4397 only; i.e., what Squid writes to the socket).
4399 icap::<st Bytes received from the ICAP server (TCP
4400 payload only; i.e., what Squid reads from
4403 icap::<bs Number of message body bytes received from the
4404 ICAP server. ICAP message body, if any, usually
4405 includes encapsulated HTTP message headers and
4406 possibly encapsulated HTTP message body. The
4407 HTTP body part is dechunked before its size is
4410 icap::tr Transaction response time (in
4411 milliseconds). The timer starts when
4412 the ICAP transaction is created and
4413 stops when the transaction is completed.
4416 icap::tio Transaction I/O time (in milliseconds). The
4417 timer starts when the first ICAP request
4418 byte is scheduled for sending. The timers
4419 stops when the last byte of the ICAP response
4422 icap::to Transaction outcome: ICAP_ERR* for all
4423 transaction errors, ICAP_OPT for OPTION
4424 transactions, ICAP_ECHO for 204
4425 responses, ICAP_MOD for message
4426 modification, and ICAP_SAT for request
4427 satisfaction. Similar to Ss.
4429 icap::Hs ICAP response status code. Similar to Hs.
4431 icap::>h ICAP request header(s). Similar to >h.
4433 icap::<h ICAP response header(s). Similar to <h.
4435 The default ICAP log format, which can be used without an explicit
4436 definition, is called icap_squid:
4438 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
4440 See also: logformat, log_icap, and %adapt::<last_h
4443 NAME: logfile_daemon
4445 DEFAULT: @DEFAULT_LOGFILED@
4446 LOC: Log::TheConfig.logfile_daemon
4448 Specify the path to the logfile-writing daemon. This daemon is
4449 used to write the access and store logs, if configured.
4451 Squid sends a number of commands to the log daemon:
4452 L<data>\n - logfile data
4457 r<n>\n - set rotate count to <n>
4458 b<n>\n - 1 = buffer output, 0 = don't buffer output
4460 No responses is expected.
4463 NAME: stats_collection
4465 LOC: Config.accessList.stats_collection
4467 DEFAULT_DOC: Allow logging for all transactions.
4468 COMMENT: allow|deny acl acl...
4470 This options allows you to control which requests gets accounted
4471 in performance counters.
4473 This clause only supports fast acl types.
4474 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4477 NAME: cache_store_log
4480 LOC: Config.Log.store
4482 Logs the activities of the storage manager. Shows which
4483 objects are ejected from the cache, and which objects are
4484 saved and for how long.
4485 There are not really utilities to analyze this data, so you can safely
4486 disable it (the default).
4488 Store log uses modular logging outputs. See access_log for the list
4489 of modules supported.
4492 cache_store_log stdio:@DEFAULT_STORE_LOG@
4493 cache_store_log daemon:@DEFAULT_STORE_LOG@
4496 NAME: cache_swap_state cache_swap_log
4498 LOC: Config.Log.swap
4500 DEFAULT_DOC: Store the journal inside its cache_dir
4502 Location for the cache "swap.state" file. This index file holds
4503 the metadata of objects saved on disk. It is used to rebuild
4504 the cache during startup. Normally this file resides in each
4505 'cache_dir' directory, but you may specify an alternate
4506 pathname here. Note you must give a full filename, not just
4507 a directory. Since this is the index for the whole object
4508 list you CANNOT periodically rotate it!
4510 If %s can be used in the file name it will be replaced with a
4511 a representation of the cache_dir name where each / is replaced
4512 with '.'. This is needed to allow adding/removing cache_dir
4513 lines when cache_swap_log is being used.
4515 If have more than one 'cache_dir', and %s is not used in the name
4516 these swap logs will have names such as:
4522 The numbered extension (which is added automatically)
4523 corresponds to the order of the 'cache_dir' lines in this
4524 configuration file. If you change the order of the 'cache_dir'
4525 lines in this file, these index files will NOT correspond to
4526 the correct 'cache_dir' entry (unless you manually rename
4527 them). We recommend you do NOT use this option. It is
4528 better to keep these index files in each 'cache_dir' directory.
4531 NAME: logfile_rotate
4534 LOC: Config.Log.rotateNumber
4536 Specifies the default number of logfile rotations to make when you
4537 type 'squid -k rotate'. The default is 10, which will rotate
4538 with extensions 0 through 9. Setting logfile_rotate to 0 will
4539 disable the file name rotation, but the logfiles are still closed
4540 and re-opened. This will enable you to rename the logfiles
4541 yourself just before sending the rotate signal.
4543 Note, from Squid-3.1 this option is only a default for cache.log,
4544 that log can be rotated separately by using debug_options.
4546 Note, from Squid-3.6 this option is only a default for access.log
4547 recorded by stdio: module. Those logs can be rotated separately by
4548 using the rotate=N option on their access_log directive.
4550 Note, the 'squid -k rotate' command normally sends a USR1
4551 signal to the running squid process. In certain situations
4552 (e.g. on Linux with Async I/O), USR1 is used for other
4553 purposes, so -k rotate uses another signal. It is best to get
4554 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4561 DEFAULT: @DEFAULT_MIME_TABLE@
4562 LOC: Config.mimeTablePathname
4564 Path to Squid's icon configuration file.
4566 You shouldn't need to change this, but the default file contains
4567 examples and formatting information if you do.
4573 LOC: Config.onoff.log_mime_hdrs
4576 The Cache can record both the request and the response MIME
4577 headers for each HTTP transaction. The headers are encoded
4578 safely and will appear as two bracketed fields at the end of
4579 the access log (for either the native or httpd-emulated log
4580 formats). To enable this logging set log_mime_hdrs to 'on'.
4585 DEFAULT: @DEFAULT_PID_FILE@
4586 LOC: Config.pidFilename
4588 A filename to write the process-id to. To disable, enter "none".
4591 NAME: client_netmask
4593 LOC: Config.Addrs.client_netmask
4595 DEFAULT_DOC: Log full client IP address
4597 A netmask for client addresses in logfiles and cachemgr output.
4598 Change this to protect the privacy of your cache clients.
4599 A netmask of 255.255.255.0 will log all IP's in that range with
4600 the last digit set to '0'.
4603 NAME: strip_query_terms
4605 LOC: Config.onoff.strip_query_terms
4608 By default, Squid strips query terms from requested URLs before
4609 logging. This protects your user's privacy and reduces log size.
4611 When investigating HIT/MISS or other caching behaviour you
4612 will need to disable this to see the full URL used by Squid.
4619 LOC: Config.onoff.buffered_logs
4621 Whether to write/send access_log records ASAP or accumulate them and
4622 then write/send them in larger chunks. Buffering may improve
4623 performance because it decreases the number of I/Os. However,
4624 buffering increases the delay before log records become available to
4625 the final recipient (e.g., a disk file or logging daemon) and,
4626 hence, increases the risk of log records loss.
4628 Note that even when buffered_logs are off, Squid may have to buffer
4629 records if it cannot write/send them immediately due to pending I/Os
4630 (e.g., the I/O writing the previous log record) or connectivity loss.
4632 Currently honored by 'daemon' and 'tcp' access_log modules only.
4635 NAME: netdb_filename
4637 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4638 LOC: Config.netdbFilename
4641 Where Squid stores it's netdb journal.
4642 When enabled this journal preserves netdb state between restarts.
4644 To disable, enter "none".
4648 OPTIONS FOR TROUBLESHOOTING
4649 -----------------------------------------------------------------------------
4654 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4655 LOC: Debug::cache_log
4657 Squid administrative logging file.
4659 This is where general information about Squid behavior goes. You can
4660 increase the amount of data logged to this file and how often it is
4661 rotated with "debug_options"
4667 DEFAULT_DOC: Log all critical and important messages.
4668 LOC: Debug::debugOptions
4670 Logging options are set as section,level where each source file
4671 is assigned a unique section. Lower levels result in less
4672 output, Full debugging (level 9) can result in a very large
4673 log file, so be careful.
4675 The magic word "ALL" sets debugging levels for all sections.
4676 The default is to run with "ALL,1" to record important warnings.
4678 The rotate=N option can be used to keep more or less of these logs
4679 than would otherwise be kept by logfile_rotate.
4680 For most uses a single log should be enough to monitor current
4681 events affecting Squid.
4686 LOC: Config.coredump_dir
4687 DEFAULT_IF_NONE: none
4688 DEFAULT_DOC: Use the directory from where Squid was started.
4690 By default Squid leaves core files in the directory from where
4691 it was started. If you set 'coredump_dir' to a directory
4692 that exists, Squid will chdir() to that directory at startup
4693 and coredump files will be left there.
4697 # Leave coredumps in the first cache dir
4698 coredump_dir @DEFAULT_SWAP_DIR@
4704 OPTIONS FOR FTP GATEWAYING
4705 -----------------------------------------------------------------------------
4711 LOC: Config.Ftp.anon_user
4713 If you want the anonymous login password to be more informative
4714 (and enable the use of picky FTP servers), set this to something
4715 reasonable for your domain, like wwwuser@somewhere.net
4717 The reason why this is domainless by default is the
4718 request can be made on the behalf of a user in any domain,
4719 depending on how the cache is used.
4720 Some FTP server also validate the email address is valid
4721 (for example perl.com).
4727 LOC: Config.Ftp.passive
4729 If your firewall does not allow Squid to use passive
4730 connections, turn off this option.
4732 Use of ftp_epsv_all option requires this to be ON.
4738 LOC: Config.Ftp.epsv_all
4740 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4742 NATs may be able to put the connection on a "fast path" through the
4743 translator, as the EPRT command will never be used and therefore,
4744 translation of the data portion of the segments will never be needed.
4746 When a client only expects to do two-way FTP transfers this may be
4748 If squid finds that it must do a three-way FTP transfer after issuing
4749 an EPSV ALL command, the FTP session will fail.
4751 If you have any doubts about this option do not use it.
4752 Squid will nicely attempt all other connection methods.
4754 Requires ftp_passive to be ON (default) for any effect.
4760 LOC: Config.accessList.ftp_epsv
4762 FTP Protocol extensions permit the use of a special "EPSV" command.
4764 NATs may be able to put the connection on a "fast path" through the
4765 translator using EPSV, as the EPRT command will never be used
4766 and therefore, translation of the data portion of the segments
4767 will never be needed.
4769 EPSV is often required to interoperate with FTP servers on IPv6
4770 networks. On the other hand, it may break some IPv4 servers.
4772 By default, EPSV may try EPSV with any FTP server. To fine tune
4773 that decision, you may restrict EPSV to certain clients or servers
4776 ftp_epsv allow|deny al1 acl2 ...
4778 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
4780 Only fast ACLs are supported.
4781 Requires ftp_passive to be ON (default) for any effect.
4787 LOC: Config.Ftp.eprt
4789 FTP Protocol extensions permit the use of a special "EPRT" command.
4791 This extension provides a protocol neutral alternative to the
4792 IPv4-only PORT command. When supported it enables active FTP data
4793 channels over IPv6 and efficient NAT handling.
4795 Turning this OFF will prevent EPRT being attempted and will skip
4796 straight to using PORT for IPv4 servers.
4798 Some devices are known to not handle this extension correctly and
4799 may result in crashes. Devices which suport EPRT enough to fail
4800 cleanly will result in Squid attempting PORT anyway. This directive
4801 should only be disabled when EPRT results in device failures.
4803 WARNING: Doing so will convert Squid back to the old behavior with all
4804 the related problems with external NAT devices/layers and IPv4-only FTP.
4807 NAME: ftp_sanitycheck
4810 LOC: Config.Ftp.sanitycheck
4812 For security and data integrity reasons Squid by default performs
4813 sanity checks of the addresses of FTP data connections ensure the
4814 data connection is to the requested server. If you need to allow
4815 FTP connections to servers using another IP address for the data
4816 connection turn this off.
4819 NAME: ftp_telnet_protocol
4822 LOC: Config.Ftp.telnet
4824 The FTP protocol is officially defined to use the telnet protocol
4825 as transport channel for the control connection. However, many
4826 implementations are broken and does not respect this aspect of
4829 If you have trouble accessing files with ASCII code 255 in the
4830 path or similar problems involving this ASCII code you can
4831 try setting this directive to off. If that helps, report to the
4832 operator of the FTP server in question that their FTP server
4833 is broken and does not follow the FTP standard.
4837 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4838 -----------------------------------------------------------------------------
4843 DEFAULT: @DEFAULT_DISKD@
4844 LOC: Config.Program.diskd
4846 Specify the location of the diskd executable.
4847 Note this is only useful if you have compiled in
4848 diskd as one of the store io modules.
4851 NAME: unlinkd_program
4854 DEFAULT: @DEFAULT_UNLINKD@
4855 LOC: Config.Program.unlinkd
4857 Specify the location of the executable for file deletion process.
4860 NAME: pinger_program
4863 DEFAULT: @DEFAULT_PINGER@
4866 Specify the location of the executable for the pinger process.
4875 Control whether the pinger is active at run-time.
4876 Enables turning ICMP pinger on and off with a simple
4877 squid -k reconfigure.
4882 OPTIONS FOR URL REWRITING
4883 -----------------------------------------------------------------------------
4886 NAME: url_rewrite_program redirect_program
4888 LOC: Config.Program.redirect
4891 Specify the location of the executable URL rewriter to use.
4892 Since they can perform almost any function there isn't one included.
4894 For each requested URL, the rewriter will receive on line with the format
4896 [channel-ID <SP>] URL [<SP> extras]<NL>
4898 See url_rewrite_extras on how to send "extras" with optional values to
4900 After processing the request the helper must reply using the following format:
4902 [channel-ID <SP>] result [<SP> kv-pairs]
4904 The result code can be:
4906 OK status=30N url="..."
4907 Redirect the URL to the one supplied in 'url='.
4908 'status=' is optional and contains the status code to send
4909 the client in Squids HTTP response. It must be one of the
4910 HTTP redirect status codes: 301, 302, 303, 307, 308.
4911 When no status is given Squid will use 302.
4913 OK rewrite-url="..."
4914 Rewrite the URL to the one supplied in 'rewrite-url='.
4915 The new URL is fetched directly by Squid and returned to
4916 the client as the response to its request.
4919 When neither of url= and rewrite-url= are sent Squid does
4923 Do not change the URL.
4926 An internal error occurred in the helper, preventing
4927 a result being identified. The 'message=' key name is
4928 reserved for delivering a log message.
4931 In addition to the above kv-pairs Squid also understands the following
4932 optional kv-pairs received from URL rewriters:
4934 Associates a TAG with the client TCP connection.
4935 The TAG is treated as a regular annotation but persists across
4936 future requests on the client connection rather than just the
4937 current request. A helper may update the TAG during subsequent
4938 requests be returning a new kv-pair.
4940 When using the concurrency= option the protocol is changed by
4941 introducing a query channel tag in front of the request/response.
4942 The query channel tag is a number between 0 and concurrency-1.
4943 This value must be echoed back unchanged to Squid as the first part
4944 of the response relating to its request.
4946 WARNING: URL re-writing ability should be avoided whenever possible.
4947 Use the URL redirect form of response instead.
4949 Re-write creates a difference in the state held by the client
4950 and server. Possibly causing confusion when the server response
4951 contains snippets of its view state. Embeded URLs, response
4952 and content Location headers, etc. are not re-written by this
4955 By default, a URL rewriter is not used.
4958 NAME: url_rewrite_children redirect_children
4959 TYPE: HelperChildConfig
4960 DEFAULT: 20 startup=0 idle=1 concurrency=0
4961 LOC: Config.redirectChildren
4963 The maximum number of redirector processes to spawn. If you limit
4964 it too few Squid will have to wait for them to process a backlog of
4965 URLs, slowing it down. If you allow too many they will use RAM
4966 and other system resources noticably.
4968 The startup= and idle= options allow some measure of skew in your
4973 Sets a minimum of how many processes are to be spawned when Squid
4974 starts or reconfigures. When set to zero the first request will
4975 cause spawning of the first child process to handle it.
4977 Starting too few will cause an initial slowdown in traffic as Squid
4978 attempts to simultaneously spawn enough processes to cope.
4982 Sets a minimum of how many processes Squid is to try and keep available
4983 at all times. When traffic begins to rise above what the existing
4984 processes can handle this many more will be spawned up to the maximum
4985 configured. A minimum setting of 1 is required.
4989 The number of requests each redirector helper can handle in
4990 parallel. Defaults to 0 which indicates the redirector
4991 is a old-style single threaded redirector.
4993 When this directive is set to a value >= 1 then the protocol
4994 used to communicate with the helper is modified to include
4995 an ID in front of the request/response. The ID from the request
4996 must be echoed back with the response to that request.
5000 Sets the maximum number of queued requests.
5001 If the queued requests exceed queue size and redirector_bypass
5002 configuration option is set, then redirector is bypassed. Otherwise, if
5003 overloading persists squid may abort its operation.
5004 The default value is set to 2*numberofchildren.
5007 NAME: url_rewrite_host_header redirect_rewrites_host_header
5010 LOC: Config.onoff.redir_rewrites_host
5012 To preserve same-origin security policies in browsers and
5013 prevent Host: header forgery by redirectors Squid rewrites
5014 any Host: header in redirected requests.
5016 If you are running an accelerator this may not be a wanted
5017 effect of a redirector. This directive enables you disable
5018 Host: alteration in reverse-proxy traffic.
5020 WARNING: Entries are cached on the result of the URL rewriting
5021 process, so be careful if you have domain-virtual hosts.
5023 WARNING: Squid and other software verifies the URL and Host
5024 are matching, so be careful not to relay through other proxies
5025 or inspecting firewalls with this disabled.
5028 NAME: url_rewrite_access redirector_access
5031 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5032 LOC: Config.accessList.redirector
5034 If defined, this access list specifies which requests are
5035 sent to the redirector processes.
5037 This clause supports both fast and slow acl types.
5038 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5041 NAME: url_rewrite_bypass redirector_bypass
5043 LOC: Config.onoff.redirector_bypass
5046 When this is 'on', a request will not go through the
5047 redirector if all the helpers are busy. If this is 'off'
5048 and the redirector queue grows too large, Squid will exit
5049 with a FATAL error and ask you to increase the number of
5050 redirectors. You should only enable this if the redirectors
5051 are not critical to your caching system. If you use
5052 redirectors for access control, and you enable this option,
5053 users may have access to pages they should not
5054 be allowed to request.
5055 This options sets default queue-size option of the url_rewrite_children
5059 NAME: url_rewrite_extras
5060 TYPE: TokenOrQuotedString
5061 LOC: Config.redirector_extras
5062 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5064 Specifies a string to be append to request line format for the
5065 rewriter helper. "Quoted" format values may contain spaces and
5066 logformat %macros. In theory, any logformat %macro can be used.
5067 In practice, a %macro expands as a dash (-) if the helper request is
5068 sent before the required macro information is available to Squid.
5071 NAME: url_rewrite_timeout
5072 TYPE: UrlHelperTimeout
5073 LOC: Config.onUrlRewriteTimeout
5075 DEFAULT_DOC: Squid waits for the helper response forever
5077 Squid times active requests to redirector. The timeout value and Squid
5078 reaction to a timed out request are configurable using the following
5081 url_rewrite_timeout timeout time-units on_timeout=<action> [response=<quoted-response>]
5083 supported timeout actions:
5084 fail Squid return a ERR_GATEWAY_FAILURE error page
5086 bypass Do not re-write the URL
5088 retry Send the lookup to the helper again
5090 use_configured_response
5091 Use the <quoted-response> as helper response
5095 OPTIONS FOR STORE ID
5096 -----------------------------------------------------------------------------
5099 NAME: store_id_program storeurl_rewrite_program
5101 LOC: Config.Program.store_id
5104 Specify the location of the executable StoreID helper to use.
5105 Since they can perform almost any function there isn't one included.
5107 For each requested URL, the helper will receive one line with the format
5109 [channel-ID <SP>] URL [<SP> extras]<NL>
5112 After processing the request the helper must reply using the following format:
5114 [channel-ID <SP>] result [<SP> kv-pairs]
5116 The result code can be:
5119 Use the StoreID supplied in 'store-id='.
5122 The default is to use HTTP request URL as the store ID.
5125 An internal error occured in the helper, preventing
5126 a result being identified.
5128 In addition to the above kv-pairs Squid also understands the following
5129 optional kv-pairs received from URL rewriters:
5131 Associates a TAG with the client TCP connection.
5132 Please see url_rewrite_program related documentation for this
5135 Helper programs should be prepared to receive and possibly ignore
5136 additional whitespace-separated tokens on each input line.
5138 When using the concurrency= option the protocol is changed by
5139 introducing a query channel tag in front of the request/response.
5140 The query channel tag is a number between 0 and concurrency-1.
5141 This value must be echoed back unchanged to Squid as the first part
5142 of the response relating to its request.
5144 NOTE: when using StoreID refresh_pattern will apply to the StoreID
5145 returned from the helper and not the URL.
5147 WARNING: Wrong StoreID value returned by a careless helper may result
5148 in the wrong cached response returned to the user.
5150 By default, a StoreID helper is not used.
5153 NAME: store_id_extras
5154 TYPE: TokenOrQuotedString
5155 LOC: Config.storeId_extras
5156 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5158 Specifies a string to be append to request line format for the
5159 StoreId helper. "Quoted" format values may contain spaces and
5160 logformat %macros. In theory, any logformat %macro can be used.
5161 In practice, a %macro expands as a dash (-) if the helper request is
5162 sent before the required macro information is available to Squid.
5165 NAME: store_id_children storeurl_rewrite_children
5166 TYPE: HelperChildConfig
5167 DEFAULT: 20 startup=0 idle=1 concurrency=0
5168 LOC: Config.storeIdChildren
5170 The maximum number of StoreID helper processes to spawn. If you limit
5171 it too few Squid will have to wait for them to process a backlog of
5172 requests, slowing it down. If you allow too many they will use RAM
5173 and other system resources noticably.
5175 The startup= and idle= options allow some measure of skew in your
5180 Sets a minimum of how many processes are to be spawned when Squid
5181 starts or reconfigures. When set to zero the first request will
5182 cause spawning of the first child process to handle it.
5184 Starting too few will cause an initial slowdown in traffic as Squid
5185 attempts to simultaneously spawn enough processes to cope.
5189 Sets a minimum of how many processes Squid is to try and keep available
5190 at all times. When traffic begins to rise above what the existing
5191 processes can handle this many more will be spawned up to the maximum
5192 configured. A minimum setting of 1 is required.
5196 The number of requests each storeID helper can handle in
5197 parallel. Defaults to 0 which indicates the helper
5198 is a old-style single threaded program.
5200 When this directive is set to a value >= 1 then the protocol
5201 used to communicate with the helper is modified to include
5202 an ID in front of the request/response. The ID from the request
5203 must be echoed back with the response to that request.
5207 Sets the maximum number of queued requests.
5208 If the queued requests exceed queue size and store_id_bypass
5209 configuration option is set, then storeID helper is bypassed. Otherwise,
5210 if overloading persists squid may abort its operation.
5211 The default value is set to 2*numberofchildren.
5214 NAME: store_id_access storeurl_rewrite_access
5217 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5218 LOC: Config.accessList.store_id
5220 If defined, this access list specifies which requests are
5221 sent to the StoreID processes. By default all requests
5224 This clause supports both fast and slow acl types.
5225 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5228 NAME: store_id_bypass storeurl_rewrite_bypass
5230 LOC: Config.onoff.store_id_bypass
5233 When this is 'on', a request will not go through the
5234 helper if all helpers are busy. If this is 'off'
5235 and the helper queue grows too large, Squid will exit
5236 with a FATAL error and ask you to increase the number of
5237 helpers. You should only enable this if the helperss
5238 are not critical to your caching system. If you use
5239 helpers for critical caching components, and you enable this
5240 option, users may not get objects from cache.
5241 This options sets default queue-size option of the store_id_children
5246 OPTIONS FOR TUNING THE CACHE
5247 -----------------------------------------------------------------------------
5250 NAME: cache no_cache
5253 DEFAULT_DOC: By default, this directive is unused and has no effect.
5254 LOC: Config.accessList.noCache
5256 Requests denied by this directive will not be served from the cache
5257 and their responses will not be stored in the cache. This directive
5258 has no effect on other transactions and on already cached responses.
5260 This clause supports both fast and slow acl types.
5261 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5263 This and the two other similar caching directives listed below are
5264 checked at different transaction processing stages, have different
5265 access to response information, affect different cache operations,
5266 and differ in slow ACLs support:
5268 * cache: Checked before Squid makes a hit/miss determination.
5269 No access to reply information!
5270 Denies both serving a hit and storing a miss.
5271 Supports both fast and slow ACLs.
5272 * send_hit: Checked after a hit was detected.
5273 Has access to reply (hit) information.
5274 Denies serving a hit only.
5275 Supports fast ACLs only.
5276 * store_miss: Checked before storing a cachable miss.
5277 Has access to reply (miss) information.
5278 Denies storing a miss only.
5279 Supports fast ACLs only.
5281 If you are not sure which of the three directives to use, apply the
5282 following decision logic:
5284 * If your ACL(s) are of slow type _and_ need response info, redesign.
5285 Squid does not support that particular combination at this time.
5287 * If your directive ACL(s) are of slow type, use "cache"; and/or
5288 * if your directive ACL(s) need no response info, use "cache".
5290 * If you do not want the response cached, use store_miss; and/or
5291 * if you do not want a hit on a cached response, use send_hit.
5297 DEFAULT_DOC: By default, this directive is unused and has no effect.
5298 LOC: Config.accessList.sendHit
5300 Responses denied by this directive will not be served from the cache
5301 (but may still be cached, see store_miss). This directive has no
5302 effect on the responses it allows and on the cached objects.
5304 Please see the "cache" directive for a summary of differences among
5305 store_miss, send_hit, and cache directives.
5307 Unlike the "cache" directive, send_hit only supports fast acl
5308 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5312 # apply custom Store ID mapping to some URLs
5313 acl MapMe dstdomain .c.example.com
5314 store_id_program ...
5315 store_id_access allow MapMe
5317 # but prevent caching of special responses
5318 # such as 302 redirects that cause StoreID loops
5319 acl Ordinary http_status 200-299
5320 store_miss deny MapMe !Ordinary
5322 # and do not serve any previously stored special responses
5323 # from the cache (in case they were already cached before
5324 # the above store_miss rule was in effect).
5325 send_hit deny MapMe !Ordinary
5331 DEFAULT_DOC: By default, this directive is unused and has no effect.
5332 LOC: Config.accessList.storeMiss
5334 Responses denied by this directive will not be cached (but may still
5335 be served from the cache, see send_hit). This directive has no
5336 effect on the responses it allows and on the already cached responses.
5338 Please see the "cache" directive for a summary of differences among
5339 store_miss, send_hit, and cache directives. See the
5340 send_hit directive for a usage example.
5342 Unlike the "cache" directive, store_miss only supports fast acl
5343 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5349 LOC: Config.maxStale
5352 This option puts an upper limit on how stale content Squid
5353 will serve from the cache if cache validation fails.
5354 Can be overriden by the refresh_pattern max-stale option.
5357 NAME: refresh_pattern
5358 TYPE: refreshpattern
5362 usage: refresh_pattern [-i] regex min percent max [options]
5364 By default, regular expressions are CASE-SENSITIVE. To make
5365 them case-insensitive, use the -i option.
5367 'Min' is the time (in minutes) an object without an explicit
5368 expiry time should be considered fresh. The recommended
5369 value is 0, any higher values may cause dynamic applications
5370 to be erroneously cached unless the application designer
5371 has taken the appropriate actions.
5373 'Percent' is a percentage of the objects age (time since last
5374 modification age) an object without explicit expiry time
5375 will be considered fresh.
5377 'Max' is an upper limit on how long objects without an explicit
5378 expiry time will be considered fresh.
5380 options: override-expire
5390 override-expire enforces min age even if the server
5391 sent an explicit expiry time (e.g., with the
5392 Expires: header or Cache-Control: max-age). Doing this
5393 VIOLATES the HTTP standard. Enabling this feature
5394 could make you liable for problems which it causes.
5396 Note: override-expire does not enforce staleness - it only extends
5397 freshness / min. If the server returns a Expires time which
5398 is longer than your max time, Squid will still consider
5399 the object fresh for that period of time.
5401 override-lastmod enforces min age even on objects
5402 that were modified recently.
5404 reload-into-ims changes a client no-cache or ``reload''
5405 request for a cached entry into a conditional request using
5406 If-Modified-Since and/or If-None-Match headers, provided the
5407 cached entry has a Last-Modified and/or a strong ETag header.
5408 Doing this VIOLATES the HTTP standard. Enabling this feature
5409 could make you liable for problems which it causes.
5411 ignore-reload ignores a client no-cache or ``reload''
5412 header. Doing this VIOLATES the HTTP standard. Enabling
5413 this feature could make you liable for problems which
5416 ignore-no-store ignores any ``Cache-control: no-store''
5417 headers received from a server. Doing this VIOLATES
5418 the HTTP standard. Enabling this feature could make you
5419 liable for problems which it causes.
5421 ignore-private ignores any ``Cache-control: private''
5422 headers received from a server. Doing this VIOLATES
5423 the HTTP standard. Enabling this feature could make you
5424 liable for problems which it causes.
5426 refresh-ims causes squid to contact the origin server
5427 when a client issues an If-Modified-Since request. This
5428 ensures that the client will receive an updated version
5429 if one is available.
5431 store-stale stores responses even if they don't have explicit
5432 freshness or a validator (i.e., Last-Modified or an ETag)
5433 present, or if they're already stale. By default, Squid will
5434 not cache such responses because they usually can't be
5435 reused. Note that such responses will be stale by default.
5437 max-stale=NN provide a maximum staleness factor. Squid won't
5438 serve objects more stale than this even if it failed to
5439 validate the object. Default: use the max_stale global limit.
5441 Basically a cached object is:
5443 FRESH if expire > now, else STALE
5445 FRESH if lm-factor < percent, else STALE
5449 The refresh_pattern lines are checked in the order listed here.
5450 The first entry which matches is used. If none of the entries
5451 match the default will be used.
5453 Note, you must uncomment all the default lines if you want
5454 to change one. The default setting is only active if none is
5460 # Add any of your own refresh_pattern entries above these.
5462 refresh_pattern ^ftp: 1440 20% 10080
5463 refresh_pattern ^gopher: 1440 0% 1440
5464 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5465 refresh_pattern . 0 20% 4320
5469 NAME: quick_abort_min
5473 LOC: Config.quickAbort.min
5476 NAME: quick_abort_max
5480 LOC: Config.quickAbort.max
5483 NAME: quick_abort_pct
5487 LOC: Config.quickAbort.pct
5489 The cache by default continues downloading aborted requests
5490 which are almost completed (less than 16 KB remaining). This
5491 may be undesirable on slow (e.g. SLIP) links and/or very busy
5492 caches. Impatient users may tie up file descriptors and
5493 bandwidth by repeatedly requesting and immediately aborting
5496 When the user aborts a request, Squid will check the
5497 quick_abort values to the amount of data transferred until
5500 If the transfer has less than 'quick_abort_min' KB remaining,
5501 it will finish the retrieval.
5503 If the transfer has more than 'quick_abort_max' KB remaining,
5504 it will abort the retrieval.
5506 If more than 'quick_abort_pct' of the transfer has completed,
5507 it will finish the retrieval.
5509 If you do not want any retrieval to continue after the client
5510 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5513 If you want retrievals to always continue if they are being
5514 cached set 'quick_abort_min' to '-1 KB'.
5517 NAME: read_ahead_gap
5518 COMMENT: buffer-size
5520 LOC: Config.readAheadGap
5523 The amount of data the cache will buffer ahead of what has been
5524 sent to the client when retrieving an object from another server.
5528 IFDEF: USE_HTTP_VIOLATIONS
5531 LOC: Config.negativeTtl
5534 Set the Default Time-to-Live (TTL) for failed requests.
5535 Certain types of failures (such as "connection refused" and
5536 "404 Not Found") are able to be negatively-cached for a short time.
5537 Modern web servers should provide Expires: header, however if they
5538 do not this can provide a minimum TTL.
5539 The default is not to cache errors with unknown expiry details.
5541 Note that this is different from negative caching of DNS lookups.
5543 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5544 this feature could make you liable for problems which it
5548 NAME: positive_dns_ttl
5551 LOC: Config.positiveDnsTtl
5554 Upper limit on how long Squid will cache positive DNS responses.
5555 Default is 6 hours (360 minutes). This directive must be set
5556 larger than negative_dns_ttl.
5559 NAME: negative_dns_ttl
5562 LOC: Config.negativeDnsTtl
5565 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5566 This also sets the lower cache limit on positive lookups.
5567 Minimum value is 1 second, and it is not recommendable to go
5568 much below 10 seconds.
5571 NAME: range_offset_limit
5572 COMMENT: size [acl acl...]
5574 LOC: Config.rangeOffsetLimit
5577 usage: (size) [units] [[!]aclname]
5579 Sets an upper limit on how far (number of bytes) into the file
5580 a Range request may be to cause Squid to prefetch the whole file.
5581 If beyond this limit, Squid forwards the Range request as it is and
5582 the result is NOT cached.
5584 This is to stop a far ahead range request (lets say start at 17MB)
5585 from making Squid fetch the whole object up to that point before
5586 sending anything to the client.
5588 Multiple range_offset_limit lines may be specified, and they will
5589 be searched from top to bottom on each request until a match is found.
5590 The first match found will be used. If no line matches a request, the
5591 default limit of 0 bytes will be used.
5593 'size' is the limit specified as a number of units.
5595 'units' specifies whether to use bytes, KB, MB, etc.
5596 If no units are specified bytes are assumed.
5598 A size of 0 causes Squid to never fetch more than the
5599 client requested. (default)
5601 A size of 'none' causes Squid to always fetch the object from the
5602 beginning so it may cache the result. (2.0 style)
5604 'aclname' is the name of a defined ACL.
5606 NP: Using 'none' as the byte value here will override any quick_abort settings
5607 that may otherwise apply to the range request. The range request will
5608 be fully fetched from start to finish regardless of the client
5609 actions. This affects bandwidth usage.
5612 NAME: minimum_expiry_time
5615 LOC: Config.minimum_expiry_time
5618 The minimum caching time according to (Expires - Date)
5619 headers Squid honors if the object can't be revalidated.
5620 The default is 60 seconds.
5622 In reverse proxy environments it might be desirable to honor
5623 shorter object lifetimes. It is most likely better to make
5624 your server return a meaningful Last-Modified header however.
5626 In ESI environments where page fragments often have short
5627 lifetimes, this will often be best set to 0.
5630 NAME: store_avg_object_size
5634 LOC: Config.Store.avgObjectSize
5636 Average object size, used to estimate number of objects your
5637 cache can hold. The default is 13 KB.
5639 This is used to pre-seed the cache index memory allocation to
5640 reduce expensive reallocate operations while handling clients
5641 traffic. Too-large values may result in memory allocation during
5642 peak traffic, too-small values will result in wasted memory.
5644 Check the cache manager 'info' report metrics for the real
5645 object sizes seen by your Squid before tuning this.
5648 NAME: store_objects_per_bucket
5651 LOC: Config.Store.objectsPerBucket
5653 Target number of objects per bucket in the store hash table.
5654 Lowering this value increases the total number of buckets and
5655 also the storage maintenance rate. The default is 20.
5660 -----------------------------------------------------------------------------
5663 NAME: request_header_max_size
5667 LOC: Config.maxRequestHeaderSize
5669 This specifies the maximum size for HTTP headers in a request.
5670 Request headers are usually relatively small (about 512 bytes).
5671 Placing a limit on the request header size will catch certain
5672 bugs (for example with persistent connections) and possibly
5673 buffer-overflow or denial-of-service attacks.
5676 NAME: reply_header_max_size
5680 LOC: Config.maxReplyHeaderSize
5682 This specifies the maximum size for HTTP headers in a reply.
5683 Reply headers are usually relatively small (about 512 bytes).
5684 Placing a limit on the reply header size will catch certain
5685 bugs (for example with persistent connections) and possibly
5686 buffer-overflow or denial-of-service attacks.
5689 NAME: request_body_max_size
5693 DEFAULT_DOC: No limit.
5694 LOC: Config.maxRequestBodySize
5696 This specifies the maximum size for an HTTP request body.
5697 In other words, the maximum size of a PUT/POST request.
5698 A user who attempts to send a request with a body larger
5699 than this limit receives an "Invalid Request" error message.
5700 If you set this parameter to a zero (the default), there will
5701 be no limit imposed.
5703 See also client_request_buffer_max_size for an alternative
5704 limitation on client uploads which can be configured.
5707 NAME: client_request_buffer_max_size
5711 LOC: Config.maxRequestBufferSize
5713 This specifies the maximum buffer size of a client request.
5714 It prevents squid eating too much memory when somebody uploads
5719 IFDEF: USE_HTTP_VIOLATIONS
5722 DEFAULT_DOC: Obey RFC 2616.
5723 LOC: Config.accessList.brokenPosts
5725 A list of ACL elements which, if matched, causes Squid to send
5726 an extra CRLF pair after the body of a PUT/POST request.
5728 Some HTTP servers has broken implementations of PUT/POST,
5729 and rely on an extra CRLF pair sent by some WWW clients.
5731 Quote from RFC2616 section 4.1 on this matter:
5733 Note: certain buggy HTTP/1.0 client implementations generate an
5734 extra CRLF's after a POST request. To restate what is explicitly
5735 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5736 a request with an extra CRLF.
5738 This clause only supports fast acl types.
5739 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5742 acl buggy_server url_regex ^http://....
5743 broken_posts allow buggy_server
5746 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5749 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5751 LOC: Adaptation::Config::use_indirect_client
5753 Controls whether the indirect client IP address (instead of the direct
5754 client IP address) is passed to adaptation services.
5756 See also: follow_x_forwarded_for adaptation_send_client_ip
5760 IFDEF: USE_HTTP_VIOLATIONS
5764 LOC: Config.onoff.via
5766 If set (default), Squid will include a Via header in requests and
5767 replies as required by RFC2616.
5773 LOC: Config.onoff.ie_refresh
5776 Microsoft Internet Explorer up until version 5.5 Service
5777 Pack 1 has an issue with transparent proxies, wherein it
5778 is impossible to force a refresh. Turning this on provides
5779 a partial fix to the problem, by causing all IMS-REFRESH
5780 requests from older IE versions to check the origin server
5781 for fresh content. This reduces hit ratio by some amount
5782 (~10% in my experience), but allows users to actually get
5783 fresh content when they want it. Note because Squid
5784 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5785 of 5.5 is unchanged from old versions of Squid (i.e. a
5786 forced refresh is impossible). Newer versions of IE will,
5787 hopefully, continue to have the new behavior and will be
5788 handled based on that assumption. This option defaults to
5789 the old Squid behavior, which is better for hit ratios but
5790 worse for clients using IE, if they need to be able to
5791 force fresh content.
5794 NAME: vary_ignore_expire
5797 LOC: Config.onoff.vary_ignore_expire
5800 Many HTTP servers supporting Vary gives such objects
5801 immediate expiry time with no cache-control header
5802 when requested by a HTTP/1.0 client. This option
5803 enables Squid to ignore such expiry times until
5804 HTTP/1.1 is fully implemented.
5806 WARNING: If turned on this may eventually cause some
5807 varying objects not intended for caching to get cached.
5810 NAME: request_entities
5812 LOC: Config.onoff.request_entities
5815 Squid defaults to deny GET and HEAD requests with request entities,
5816 as the meaning of such requests are undefined in the HTTP standard
5817 even if not explicitly forbidden.
5819 Set this directive to on if you have clients which insists
5820 on sending request entities in GET or HEAD requests. But be warned
5821 that there is server software (both proxies and web servers) which
5822 can fail to properly process this kind of request which may make you
5823 vulnerable to cache pollution attacks if enabled.
5826 NAME: request_header_access
5827 IFDEF: USE_HTTP_VIOLATIONS
5828 TYPE: http_header_access
5829 LOC: Config.request_header_access
5831 DEFAULT_DOC: No limits.
5833 Usage: request_header_access header_name allow|deny [!]aclname ...
5835 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5836 this feature could make you liable for problems which it
5839 This option replaces the old 'anonymize_headers' and the
5840 older 'http_anonymizer' option with something that is much
5841 more configurable. A list of ACLs for each header name allows
5842 removal of specific header fields under specific conditions.
5844 This option only applies to outgoing HTTP request headers (i.e.,
5845 headers sent by Squid to the next HTTP hop such as a cache peer
5846 or an origin server). The option has no effect during cache hit
5847 detection. The equivalent adaptation vectoring point in ICAP
5848 terminology is post-cache REQMOD.
5850 The option is applied to individual outgoing request header
5851 fields. For each request header field F, Squid uses the first
5852 qualifying sets of request_header_access rules:
5854 1. Rules with header_name equal to F's name.
5855 2. Rules with header_name 'Other', provided F's name is not
5856 on the hard-coded list of commonly used HTTP header names.
5857 3. Rules with header_name 'All'.
5859 Within that qualifying rule set, rule ACLs are checked as usual.
5860 If ACLs of an "allow" rule match, the header field is allowed to
5861 go through as is. If ACLs of a "deny" rule match, the header is
5862 removed and request_header_replace is then checked to identify
5863 if the removed header has a replacement. If no rules within the
5864 set have matching ACLs, the header field is left as is.
5866 For example, to achieve the same behavior as the old
5867 'http_anonymizer standard' option, you should use:
5869 request_header_access From deny all
5870 request_header_access Referer deny all
5871 request_header_access User-Agent deny all
5873 Or, to reproduce the old 'http_anonymizer paranoid' feature
5876 request_header_access Authorization allow all
5877 request_header_access Proxy-Authorization allow all
5878 request_header_access Cache-Control allow all
5879 request_header_access Content-Length allow all
5880 request_header_access Content-Type allow all
5881 request_header_access Date allow all
5882 request_header_access Host allow all
5883 request_header_access If-Modified-Since allow all
5884 request_header_access Pragma allow all
5885 request_header_access Accept allow all
5886 request_header_access Accept-Charset allow all
5887 request_header_access Accept-Encoding allow all
5888 request_header_access Accept-Language allow all
5889 request_header_access Connection allow all
5890 request_header_access All deny all
5892 HTTP reply headers are controlled with the reply_header_access directive.
5894 By default, all headers are allowed (no anonymizing is performed).
5897 NAME: reply_header_access
5898 IFDEF: USE_HTTP_VIOLATIONS
5899 TYPE: http_header_access
5900 LOC: Config.reply_header_access
5902 DEFAULT_DOC: No limits.
5904 Usage: reply_header_access header_name allow|deny [!]aclname ...
5906 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5907 this feature could make you liable for problems which it
5910 This option only applies to reply headers, i.e., from the
5911 server to the client.
5913 This is the same as request_header_access, but in the other
5914 direction. Please see request_header_access for detailed
5917 For example, to achieve the same behavior as the old
5918 'http_anonymizer standard' option, you should use:
5920 reply_header_access Server deny all
5921 reply_header_access WWW-Authenticate deny all
5922 reply_header_access Link deny all
5924 Or, to reproduce the old 'http_anonymizer paranoid' feature
5927 reply_header_access Allow allow all
5928 reply_header_access WWW-Authenticate allow all
5929 reply_header_access Proxy-Authenticate allow all
5930 reply_header_access Cache-Control allow all
5931 reply_header_access Content-Encoding allow all
5932 reply_header_access Content-Length allow all
5933 reply_header_access Content-Type allow all
5934 reply_header_access Date allow all
5935 reply_header_access Expires allow all
5936 reply_header_access Last-Modified allow all
5937 reply_header_access Location allow all
5938 reply_header_access Pragma allow all
5939 reply_header_access Content-Language allow all
5940 reply_header_access Retry-After allow all
5941 reply_header_access Title allow all
5942 reply_header_access Content-Disposition allow all
5943 reply_header_access Connection allow all
5944 reply_header_access All deny all
5946 HTTP request headers are controlled with the request_header_access directive.
5948 By default, all headers are allowed (no anonymizing is
5952 NAME: request_header_replace header_replace
5953 IFDEF: USE_HTTP_VIOLATIONS
5954 TYPE: http_header_replace
5955 LOC: Config.request_header_access
5958 Usage: request_header_replace header_name message
5959 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
5961 This option allows you to change the contents of headers
5962 denied with request_header_access above, by replacing them
5963 with some fixed string.
5965 This only applies to request headers, not reply headers.
5967 By default, headers are removed if denied.
5970 NAME: reply_header_replace
5971 IFDEF: USE_HTTP_VIOLATIONS
5972 TYPE: http_header_replace
5973 LOC: Config.reply_header_access
5976 Usage: reply_header_replace header_name message
5977 Example: reply_header_replace Server Foo/1.0
5979 This option allows you to change the contents of headers
5980 denied with reply_header_access above, by replacing them
5981 with some fixed string.
5983 This only applies to reply headers, not request headers.
5985 By default, headers are removed if denied.
5988 NAME: request_header_add
5989 TYPE: HeaderWithAclList
5990 LOC: Config.request_header_add
5993 Usage: request_header_add field-name field-value acl1 [acl2] ...
5994 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
5996 This option adds header fields to outgoing HTTP requests (i.e.,
5997 request headers sent by Squid to the next HTTP hop such as a
5998 cache peer or an origin server). The option has no effect during
5999 cache hit detection. The equivalent adaptation vectoring point
6000 in ICAP terminology is post-cache REQMOD.
6002 Field-name is a token specifying an HTTP header name. If a
6003 standard HTTP header name is used, Squid does not check whether
6004 the new header conflicts with any existing headers or violates
6005 HTTP rules. If the request to be modified already contains a
6006 field with the same name, the old field is preserved but the
6007 header field values are not merged.
6009 Field-value is either a token or a quoted string. If quoted
6010 string format is used, then the surrounding quotes are removed
6011 while escape sequences and %macros are processed.
6013 In theory, all of the logformat codes can be used as %macros.
6014 However, unlike logging (which happens at the very end of
6015 transaction lifetime), the transaction may not yet have enough
6016 information to expand a macro when the new header value is needed.
6017 And some information may already be available to Squid but not yet
6018 committed where the macro expansion code can access it (report
6019 such instances!). The macro will be expanded into a single dash
6020 ('-') in such cases. Not all macros have been tested.
6022 One or more Squid ACLs may be specified to restrict header
6023 injection to matching requests. As always in squid.conf, all
6024 ACLs in an option ACL list must be satisfied for the insertion
6025 to happen. The request_header_add option supports fast ACLs
6034 This option used to log custom information about the master
6035 transaction. For example, an admin may configure Squid to log
6036 which "user group" the transaction belongs to, where "user group"
6037 will be determined based on a set of ACLs and not [just]
6038 authentication information.
6039 Values of key/value pairs can be logged using %{key}note macros:
6041 note key value acl ...
6042 logformat myFormat ... %{key}note ...
6045 NAME: relaxed_header_parser
6046 COMMENT: on|off|warn
6048 LOC: Config.onoff.relaxed_header_parser
6051 In the default "on" setting Squid accepts certain forms
6052 of non-compliant HTTP messages where it is unambiguous
6053 what the sending application intended even if the message
6054 is not correctly formatted. The messages is then normalized
6055 to the correct form when forwarded by Squid.
6057 If set to "warn" then a warning will be emitted in cache.log
6058 each time such HTTP error is encountered.
6060 If set to "off" then such HTTP errors will cause the request
6061 or response to be rejected.
6064 NAME: collapsed_forwarding
6067 LOC: Config.onoff.collapsed_forwarding
6070 This option controls whether Squid is allowed to merge multiple
6071 potentially cachable requests for the same URI before Squid knows
6072 whether the response is going to be cachable.
6074 This feature is disabled by default: Enabling collapsed forwarding
6075 needlessly delays forwarding requests that look cachable (when they are
6076 collapsed) but then need to be forwarded individually anyway because
6077 they end up being for uncachable content. However, in some cases, such
6078 as accelleration of highly cachable content with periodic or groupped
6079 expiration times, the gains from collapsing [large volumes of
6080 simultenous refresh requests] outweigh losses from such delays.
6085 -----------------------------------------------------------------------------
6088 NAME: forward_timeout
6091 LOC: Config.Timeout.forward
6094 This parameter specifies how long Squid should at most attempt in
6095 finding a forwarding path for the request before giving up.
6098 NAME: connect_timeout
6101 LOC: Config.Timeout.connect
6104 This parameter specifies how long to wait for the TCP connect to
6105 the requested server or peer to complete before Squid should
6106 attempt to find another path where to forward the request.
6109 NAME: peer_connect_timeout
6112 LOC: Config.Timeout.peer_connect
6115 This parameter specifies how long to wait for a pending TCP
6116 connection to a peer cache. The default is 30 seconds. You
6117 may also set different timeout values for individual neighbors
6118 with the 'connect-timeout' option on a 'cache_peer' line.
6124 LOC: Config.Timeout.read
6127 Applied on peer server connections.
6129 After each successful read(), the timeout will be extended by this
6130 amount. If no data is read again after this amount of time,
6131 the request is aborted and logged with ERR_READ_TIMEOUT.
6133 The default is 15 minutes.
6139 LOC: Config.Timeout.write
6142 This timeout is tracked for all connections that have data
6143 available for writing and are waiting for the socket to become
6144 ready. After each successful write, the timeout is extended by
6145 the configured amount. If Squid has data to write but the
6146 connection is not ready for the configured duration, the
6147 transaction associated with the connection is terminated. The
6148 default is 15 minutes.
6151 NAME: request_timeout
6153 LOC: Config.Timeout.request
6156 How long to wait for complete HTTP request headers after initial
6157 connection establishment.
6160 NAME: request_start_timeout
6162 LOC: Config.Timeout.request_start_timeout
6165 How long to wait for the first request byte after initial
6166 connection establishment.
6169 NAME: client_idle_pconn_timeout persistent_request_timeout
6171 LOC: Config.Timeout.clientIdlePconn
6174 How long to wait for the next HTTP request on a persistent
6175 client connection after the previous request completes.
6178 NAME: ftp_client_idle_timeout
6180 LOC: Config.Timeout.ftpClientIdle
6183 How long to wait for an FTP request on a connection to Squid ftp_port.
6184 Many FTP clients do not deal with idle connection closures well,
6185 necessitating a longer default timeout than client_idle_pconn_timeout
6186 used for incoming HTTP requests.
6189 NAME: client_lifetime
6192 LOC: Config.Timeout.lifetime
6195 The maximum amount of time a client (browser) is allowed to
6196 remain connected to the cache process. This protects the Cache
6197 from having a lot of sockets (and hence file descriptors) tied up
6198 in a CLOSE_WAIT state from remote clients that go away without
6199 properly shutting down (either because of a network failure or
6200 because of a poor client implementation). The default is one
6203 NOTE: The default value is intended to be much larger than any
6204 client would ever need to be connected to your cache. You
6205 should probably change client_lifetime only as a last resort.
6206 If you seem to have many client connections tying up
6207 filedescriptors, we recommend first tuning the read_timeout,
6208 request_timeout, persistent_request_timeout and quick_abort values.
6211 NAME: pconn_lifetime
6214 LOC: Config.Timeout.pconnLifetime
6217 Desired maximum lifetime of a persistent connection.
6218 When set, Squid will close a now-idle persistent connection that
6219 exceeded configured lifetime instead of moving the connection into
6220 the idle connection pool (or equivalent). No effect on ongoing/active
6221 transactions. Connection lifetime is the time period from the
6222 connection acceptance or opening time until "now".
6224 This limit is useful in environments with long-lived connections
6225 where Squid configuration or environmental factors change during a
6226 single connection lifetime. If unrestricted, some connections may
6227 last for hours and even days, ignoring those changes that should
6228 have affected their behavior or their existence.
6230 Currently, a new lifetime value supplied via Squid reconfiguration
6231 has no effect on already idle connections unless they become busy.
6233 When set to '0' this limit is not used.
6236 NAME: half_closed_clients
6238 LOC: Config.onoff.half_closed_clients
6241 Some clients may shutdown the sending side of their TCP
6242 connections, while leaving their receiving sides open. Sometimes,
6243 Squid can not tell the difference between a half-closed and a
6244 fully-closed TCP connection.
6246 By default, Squid will immediately close client connections when
6247 read(2) returns "no more data to read."
6249 Change this option to 'on' and Squid will keep open connections
6250 until a read(2) or write(2) on the socket returns an error.
6251 This may show some benefits for reverse proxies. But if not
6252 it is recommended to leave OFF.
6255 NAME: server_idle_pconn_timeout pconn_timeout
6257 LOC: Config.Timeout.serverIdlePconn
6260 Timeout for idle persistent connections to servers and other
6267 LOC: Ident::TheConfig.timeout
6270 Maximum time to wait for IDENT lookups to complete.
6272 If this is too high, and you enabled IDENT lookups from untrusted
6273 users, you might be susceptible to denial-of-service by having
6274 many ident requests going at once.
6277 NAME: shutdown_lifetime
6280 LOC: Config.shutdownLifetime
6283 When SIGTERM or SIGHUP is received, the cache is put into
6284 "shutdown pending" mode until all active sockets are closed.
6285 This value is the lifetime to set for all open descriptors
6286 during shutdown mode. Any active clients after this many
6287 seconds will receive a 'timeout' message.
6291 ADMINISTRATIVE PARAMETERS
6292 -----------------------------------------------------------------------------
6298 LOC: Config.adminEmail
6300 Email-address of local cache manager who will receive
6301 mail if the cache dies. The default is "webmaster".
6307 LOC: Config.EmailFrom
6309 From: email-address for mail sent when the cache dies.
6310 The default is to use 'squid@unique_hostname'.
6312 See also: unique_hostname directive.
6318 LOC: Config.EmailProgram
6320 Email program used to send mail if the cache dies.
6321 The default is "mail". The specified program must comply
6322 with the standard Unix mail syntax:
6323 mail-program recipient < mailfile
6325 Optional command line options can be specified.
6328 NAME: cache_effective_user
6330 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
6331 LOC: Config.effectiveUser
6333 If you start Squid as root, it will change its effective/real
6334 UID/GID to the user specified below. The default is to change
6335 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
6336 see also; cache_effective_group
6339 NAME: cache_effective_group
6342 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
6343 LOC: Config.effectiveGroup
6345 Squid sets the GID to the effective user's default group ID
6346 (taken from the password file) and supplementary group list
6347 from the groups membership.
6349 If you want Squid to run with a specific GID regardless of
6350 the group memberships of the effective user then set this
6351 to the group (or GID) you want Squid to run as. When set
6352 all other group privileges of the effective user are ignored
6353 and only this GID is effective. If Squid is not started as
6354 root the user starting Squid MUST be member of the specified
6357 This option is not recommended by the Squid Team.
6358 Our preference is for administrators to configure a secure
6359 user account for squid with UID/GID matching system policies.
6362 NAME: httpd_suppress_version_string
6366 LOC: Config.onoff.httpd_suppress_version_string
6368 Suppress Squid version string info in HTTP headers and HTML error pages.
6371 NAME: visible_hostname
6373 LOC: Config.visibleHostname
6375 DEFAULT_DOC: Automatically detect the system host name
6377 If you want to present a special hostname in error messages, etc,
6378 define this. Otherwise, the return value of gethostname()
6379 will be used. If you have multiple caches in a cluster and
6380 get errors about IP-forwarding you must set them to have individual
6381 names with this setting.
6384 NAME: unique_hostname
6386 LOC: Config.uniqueHostname
6388 DEFAULT_DOC: Copy the value from visible_hostname
6390 If you want to have multiple machines with the same
6391 'visible_hostname' you must give each machine a different
6392 'unique_hostname' so forwarding loops can be detected.
6395 NAME: hostname_aliases
6397 LOC: Config.hostnameAliases
6400 A list of other DNS names your cache has.
6408 Minimum umask which should be enforced while the proxy
6409 is running, in addition to the umask set at startup.
6411 For a traditional octal representation of umasks, start
6416 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6417 -----------------------------------------------------------------------------
6419 This section contains parameters for the (optional) cache
6420 announcement service. This service is provided to help
6421 cache administrators locate one another in order to join or
6422 create cache hierarchies.
6424 An 'announcement' message is sent (via UDP) to the registration
6425 service by Squid. By default, the announcement message is NOT
6426 SENT unless you enable it with 'announce_period' below.
6428 The announcement message includes your hostname, plus the
6429 following information from this configuration file:
6435 All current information is processed regularly and made
6436 available on the Web at http://www.ircache.net/Cache/Tracker/.
6439 NAME: announce_period
6441 LOC: Config.Announce.period
6443 DEFAULT_DOC: Announcement messages disabled.
6445 This is how frequently to send cache announcements.
6447 To enable announcing your cache, just set an announce period.
6450 announce_period 1 day
6455 DEFAULT: tracker.ircache.net
6456 LOC: Config.Announce.host
6458 Set the hostname where announce registration messages will be sent.
6460 See also announce_port and announce_file
6466 LOC: Config.Announce.file
6468 The contents of this file will be included in the announce
6469 registration messages.
6475 LOC: Config.Announce.port
6477 Set the port where announce registration messages will be sent.
6479 See also announce_host and announce_file
6483 HTTPD-ACCELERATOR OPTIONS
6484 -----------------------------------------------------------------------------
6487 NAME: httpd_accel_surrogate_id
6490 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
6491 LOC: Config.Accel.surrogate_id
6493 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
6494 need an identification token to allow control targeting. Because
6495 a farm of surrogates may all perform the same tasks, they may share
6496 an identification token.
6499 NAME: http_accel_surrogate_remote
6503 LOC: Config.onoff.surrogate_is_remote
6505 Remote surrogates (such as those in a CDN) honour the header
6506 "Surrogate-Control: no-store-remote".
6508 Set this to on to have squid behave as a remote surrogate.
6512 IFDEF: USE_SQUID_ESI
6513 COMMENT: libxml2|expat|custom
6515 LOC: ESIParser::Type
6518 ESI markup is not strictly XML compatible. The custom ESI parser
6519 will give higher performance, but cannot handle non ASCII character
6524 DELAY POOL PARAMETERS
6525 -----------------------------------------------------------------------------
6529 TYPE: delay_pool_count
6531 IFDEF: USE_DELAY_POOLS
6534 This represents the number of delay pools to be used. For example,
6535 if you have one class 2 delay pool and one class 3 delays pool, you
6536 have a total of 2 delay pools.
6538 See also delay_parameters, delay_class, delay_access for pool
6539 configuration details.
6543 TYPE: delay_pool_class
6545 IFDEF: USE_DELAY_POOLS
6548 This defines the class of each delay pool. There must be exactly one
6549 delay_class line for each delay pool. For example, to define two
6550 delay pools, one of class 2 and one of class 3, the settings above
6554 delay_pools 4 # 4 delay pools
6555 delay_class 1 2 # pool 1 is a class 2 pool
6556 delay_class 2 3 # pool 2 is a class 3 pool
6557 delay_class 3 4 # pool 3 is a class 4 pool
6558 delay_class 4 5 # pool 4 is a class 5 pool
6560 The delay pool classes are:
6562 class 1 Everything is limited by a single aggregate
6565 class 2 Everything is limited by a single aggregate
6566 bucket as well as an "individual" bucket chosen
6567 from bits 25 through 32 of the IPv4 address.
6569 class 3 Everything is limited by a single aggregate
6570 bucket as well as a "network" bucket chosen
6571 from bits 17 through 24 of the IP address and a
6572 "individual" bucket chosen from bits 17 through
6573 32 of the IPv4 address.
6575 class 4 Everything in a class 3 delay pool, with an
6576 additional limit on a per user basis. This
6577 only takes effect if the username is established
6578 in advance - by forcing authentication in your
6581 class 5 Requests are grouped according their tag (see
6582 external_acl's tag= reply).
6585 Each pool also requires a delay_parameters directive to configure the pool size
6586 and speed limits used whenever the pool is applied to a request. Along with
6587 a set of delay_access directives to determine when it is used.
6589 NOTE: If an IP address is a.b.c.d
6590 -> bits 25 through 32 are "d"
6591 -> bits 17 through 24 are "c"
6592 -> bits 17 through 32 are "c * 256 + d"
6594 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6595 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6597 This clause only supports fast acl types.
6598 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6600 See also delay_parameters and delay_access.
6604 TYPE: delay_pool_access
6606 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6607 IFDEF: USE_DELAY_POOLS
6610 This is used to determine which delay pool a request falls into.
6612 delay_access is sorted per pool and the matching starts with pool 1,
6613 then pool 2, ..., and finally pool N. The first delay pool where the
6614 request is allowed is selected for the request. If it does not allow
6615 the request to any pool then the request is not delayed (default).
6617 For example, if you want some_big_clients in delay
6618 pool 1 and lotsa_little_clients in delay pool 2:
6620 delay_access 1 allow some_big_clients
6621 delay_access 1 deny all
6622 delay_access 2 allow lotsa_little_clients
6623 delay_access 2 deny all
6624 delay_access 3 allow authenticated_clients
6626 See also delay_parameters and delay_class.
6630 NAME: delay_parameters
6631 TYPE: delay_pool_rates
6633 IFDEF: USE_DELAY_POOLS
6636 This defines the parameters for a delay pool. Each delay pool has
6637 a number of "buckets" associated with it, as explained in the
6638 description of delay_class.
6640 For a class 1 delay pool, the syntax is:
6642 delay_parameters pool aggregate
6644 For a class 2 delay pool:
6646 delay_parameters pool aggregate individual
6648 For a class 3 delay pool:
6650 delay_parameters pool aggregate network individual
6652 For a class 4 delay pool:
6654 delay_parameters pool aggregate network individual user
6656 For a class 5 delay pool:
6658 delay_parameters pool tagrate
6660 The option variables are:
6662 pool a pool number - ie, a number between 1 and the
6663 number specified in delay_pools as used in
6666 aggregate the speed limit parameters for the aggregate bucket
6669 individual the speed limit parameters for the individual
6670 buckets (class 2, 3).
6672 network the speed limit parameters for the network buckets
6675 user the speed limit parameters for the user buckets
6678 tagrate the speed limit parameters for the tag buckets
6681 A pair of delay parameters is written restore/maximum, where restore is
6682 the number of bytes (not bits - modem and network speeds are usually
6683 quoted in bits) per second placed into the bucket, and maximum is the
6684 maximum number of bytes which can be in the bucket at any time.
6686 There must be one delay_parameters line for each delay pool.
6689 For example, if delay pool number 1 is a class 2 delay pool as in the
6690 above example, and is being used to strictly limit each host to 64Kbit/sec
6691 (plus overheads), with no overall limit, the line is:
6693 delay_parameters 1 none 8000/8000
6695 Note that 8 x 8K Byte/sec -> 64K bit/sec.
6697 Note that the word 'none' is used to represent no limit.
6700 And, if delay pool number 2 is a class 3 delay pool as in the above
6701 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6702 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6703 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6704 to permit a decent web page to be downloaded at a decent speed
6705 (if the network is not being limited due to overuse) but slow down
6706 large downloads more significantly:
6708 delay_parameters 2 32000/32000 8000/8000 600/8000
6710 Note that 8 x 32K Byte/sec -> 256K bit/sec.
6711 8 x 8K Byte/sec -> 64K bit/sec.
6712 8 x 600 Byte/sec -> 4800 bit/sec.
6715 Finally, for a class 4 delay pool as in the example - each user will
6716 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6718 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6721 See also delay_class and delay_access.
6725 NAME: delay_initial_bucket_level
6726 COMMENT: (percent, 0-100)
6729 IFDEF: USE_DELAY_POOLS
6730 LOC: Config.Delay.initial
6732 The initial bucket percentage is used to determine how much is put
6733 in each bucket when squid starts, is reconfigured, or first notices
6734 a host accessing it (in class 2 and class 3, individual hosts and
6735 networks only have buckets associated with them once they have been
6740 CLIENT DELAY POOL PARAMETERS
6741 -----------------------------------------------------------------------------
6744 NAME: client_delay_pools
6745 TYPE: client_delay_pool_count
6747 IFDEF: USE_DELAY_POOLS
6748 LOC: Config.ClientDelay
6750 This option specifies the number of client delay pools used. It must
6751 preceed other client_delay_* options.
6754 client_delay_pools 2
6756 See also client_delay_parameters and client_delay_access.
6759 NAME: client_delay_initial_bucket_level
6760 COMMENT: (percent, 0-no_limit)
6763 IFDEF: USE_DELAY_POOLS
6764 LOC: Config.ClientDelay.initial
6766 This option determines the initial bucket size as a percentage of
6767 max_bucket_size from client_delay_parameters. Buckets are created
6768 at the time of the "first" connection from the matching IP. Idle
6769 buckets are periodically deleted up.
6771 You can specify more than 100 percent but note that such "oversized"
6772 buckets are not refilled until their size goes down to max_bucket_size
6773 from client_delay_parameters.
6776 client_delay_initial_bucket_level 50
6779 NAME: client_delay_parameters
6780 TYPE: client_delay_pool_rates
6782 IFDEF: USE_DELAY_POOLS
6783 LOC: Config.ClientDelay
6786 This option configures client-side bandwidth limits using the
6789 client_delay_parameters pool speed_limit max_bucket_size
6791 pool is an integer ID used for client_delay_access matching.
6793 speed_limit is bytes added to the bucket per second.
6795 max_bucket_size is the maximum size of a bucket, enforced after any
6796 speed_limit additions.
6798 Please see the delay_parameters option for more information and
6802 client_delay_parameters 1 1024 2048
6803 client_delay_parameters 2 51200 16384
6805 See also client_delay_access.
6809 NAME: client_delay_access
6810 TYPE: client_delay_pool_access
6812 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6813 IFDEF: USE_DELAY_POOLS
6814 LOC: Config.ClientDelay
6816 This option determines the client-side delay pool for the
6819 client_delay_access pool_ID allow|deny acl_name
6821 All client_delay_access options are checked in their pool ID
6822 order, starting with pool 1. The first checked pool with allowed
6823 request is selected for the request. If no ACL matches or there
6824 are no client_delay_access options, the request bandwidth is not
6827 The ACL-selected pool is then used to find the
6828 client_delay_parameters for the request. Client-side pools are
6829 not used to aggregate clients. Clients are always aggregated
6830 based on their source IP addresses (one bucket per source IP).
6832 This clause only supports fast acl types.
6833 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6834 Additionally, only the client TCP connection details are available.
6835 ACLs testing HTTP properties will not work.
6837 Please see delay_access for more examples.
6840 client_delay_access 1 allow low_rate_network
6841 client_delay_access 2 allow vips_network
6844 See also client_delay_parameters and client_delay_pools.
6848 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6849 -----------------------------------------------------------------------------
6854 LOC: Config.Wccp.router
6856 DEFAULT_DOC: WCCP disabled.
6859 Use this option to define your WCCP ``home'' router for
6862 wccp_router supports a single WCCP(v1) router
6864 wccp2_router supports multiple WCCPv2 routers
6866 only one of the two may be used at the same time and defines
6867 which version of WCCP to use.
6871 TYPE: IpAddress_list
6872 LOC: Config.Wccp2.router
6874 DEFAULT_DOC: WCCPv2 disabled.
6877 Use this option to define your WCCP ``home'' router for
6880 wccp_router supports a single WCCP(v1) router
6882 wccp2_router supports multiple WCCPv2 routers
6884 only one of the two may be used at the same time and defines
6885 which version of WCCP to use.
6890 LOC: Config.Wccp.version
6894 This directive is only relevant if you need to set up WCCP(v1)
6895 to some very old and end-of-life Cisco routers. In all other
6896 setups it must be left unset or at the default setting.
6897 It defines an internal version in the WCCP(v1) protocol,
6898 with version 4 being the officially documented protocol.
6900 According to some users, Cisco IOS 11.2 and earlier only
6901 support WCCP version 3. If you're using that or an earlier
6902 version of IOS, you may need to change this value to 3, otherwise
6903 do not specify this parameter.
6906 NAME: wccp2_rebuild_wait
6908 LOC: Config.Wccp2.rebuildwait
6912 If this is enabled Squid will wait for the cache dir rebuild to finish
6913 before sending the first wccp2 HereIAm packet
6916 NAME: wccp2_forwarding_method
6918 LOC: Config.Wccp2.forwarding_method
6922 WCCP2 allows the setting of forwarding methods between the
6923 router/switch and the cache. Valid values are as follows:
6925 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6926 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6928 Currently (as of IOS 12.4) cisco routers only support GRE.
6929 Cisco switches only support the L2 redirect assignment method.
6932 NAME: wccp2_return_method
6934 LOC: Config.Wccp2.return_method
6938 WCCP2 allows the setting of return methods between the
6939 router/switch and the cache for packets that the cache
6940 decides not to handle. Valid values are as follows:
6942 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6943 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6945 Currently (as of IOS 12.4) cisco routers only support GRE.
6946 Cisco switches only support the L2 redirect assignment.
6948 If the "ip wccp redirect exclude in" command has been
6949 enabled on the cache interface, then it is still safe for
6950 the proxy server to use a l2 redirect method even if this
6951 option is set to GRE.
6954 NAME: wccp2_assignment_method
6956 LOC: Config.Wccp2.assignment_method
6960 WCCP2 allows the setting of methods to assign the WCCP hash
6961 Valid values are as follows:
6963 hash - Hash assignment
6964 mask - Mask assignment
6966 As a general rule, cisco routers support the hash assignment method
6967 and cisco switches support the mask assignment method.
6972 LOC: Config.Wccp2.info
6973 DEFAULT_IF_NONE: standard 0
6974 DEFAULT_DOC: Use the 'web-cache' standard service.
6977 WCCP2 allows for multiple traffic services. There are two
6978 types: "standard" and "dynamic". The standard type defines
6979 one service id - http (id 0). The dynamic service ids can be from
6980 51 to 255 inclusive. In order to use a dynamic service id
6981 one must define the type of traffic to be redirected; this is done
6982 using the wccp2_service_info option.
6984 The "standard" type does not require a wccp2_service_info option,
6985 just specifying the service id will suffice.
6987 MD5 service authentication can be enabled by adding
6988 "password=<password>" to the end of this service declaration.
6992 wccp2_service standard 0 # for the 'web-cache' standard service
6993 wccp2_service dynamic 80 # a dynamic service type which will be
6994 # fleshed out with subsequent options.
6995 wccp2_service standard 0 password=foo
6998 NAME: wccp2_service_info
6999 TYPE: wccp2_service_info
7000 LOC: Config.Wccp2.info
7004 Dynamic WCCPv2 services require further information to define the
7005 traffic you wish to have diverted.
7009 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
7010 priority=<priority> ports=<port>,<port>..
7012 The relevant WCCPv2 flags:
7013 + src_ip_hash, dst_ip_hash
7014 + source_port_hash, dst_port_hash
7015 + src_ip_alt_hash, dst_ip_alt_hash
7016 + src_port_alt_hash, dst_port_alt_hash
7019 The port list can be one to eight entries.
7023 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
7024 priority=240 ports=80
7026 Note: the service id must have been defined by a previous
7027 'wccp2_service dynamic <id>' entry.
7032 LOC: Config.Wccp2.weight
7036 Each cache server gets assigned a set of the destination
7037 hash proportional to their weight.
7042 LOC: Config.Wccp.address
7044 DEFAULT_DOC: Address selected by the operating system.
7047 Use this option if you require WCCPv2 to use a specific
7050 The default behavior is to not bind to any specific address.
7055 LOC: Config.Wccp2.address
7057 DEFAULT_DOC: Address selected by the operating system.
7060 Use this option if you require WCCP to use a specific
7063 The default behavior is to not bind to any specific address.
7067 PERSISTENT CONNECTION HANDLING
7068 -----------------------------------------------------------------------------
7070 Also see "pconn_timeout" in the TIMEOUTS section
7073 NAME: client_persistent_connections
7075 LOC: Config.onoff.client_pconns
7078 Persistent connection support for clients.
7079 Squid uses persistent connections (when allowed). You can use
7080 this option to disable persistent connections with clients.
7083 NAME: server_persistent_connections
7085 LOC: Config.onoff.server_pconns
7088 Persistent connection support for servers.
7089 Squid uses persistent connections (when allowed). You can use
7090 this option to disable persistent connections with servers.
7093 NAME: persistent_connection_after_error
7095 LOC: Config.onoff.error_pconns
7098 With this directive the use of persistent connections after
7099 HTTP errors can be disabled. Useful if you have clients
7100 who fail to handle errors on persistent connections proper.
7103 NAME: detect_broken_pconn
7105 LOC: Config.onoff.detect_broken_server_pconns
7108 Some servers have been found to incorrectly signal the use
7109 of HTTP/1.0 persistent connections even on replies not
7110 compatible, causing significant delays. This server problem
7111 has mostly been seen on redirects.
7113 By enabling this directive Squid attempts to detect such
7114 broken replies and automatically assume the reply is finished
7115 after 10 seconds timeout.
7119 CACHE DIGEST OPTIONS
7120 -----------------------------------------------------------------------------
7123 NAME: digest_generation
7124 IFDEF: USE_CACHE_DIGESTS
7126 LOC: Config.onoff.digest_generation
7129 This controls whether the server will generate a Cache Digest
7130 of its contents. By default, Cache Digest generation is
7131 enabled if Squid is compiled with --enable-cache-digests defined.
7134 NAME: digest_bits_per_entry
7135 IFDEF: USE_CACHE_DIGESTS
7137 LOC: Config.digest.bits_per_entry
7140 This is the number of bits of the server's Cache Digest which
7141 will be associated with the Digest entry for a given HTTP
7142 Method and URL (public key) combination. The default is 5.
7145 NAME: digest_rebuild_period
7146 IFDEF: USE_CACHE_DIGESTS
7149 LOC: Config.digest.rebuild_period
7152 This is the wait time between Cache Digest rebuilds.
7155 NAME: digest_rewrite_period
7157 IFDEF: USE_CACHE_DIGESTS
7159 LOC: Config.digest.rewrite_period
7162 This is the wait time between Cache Digest writes to
7166 NAME: digest_swapout_chunk_size
7169 IFDEF: USE_CACHE_DIGESTS
7170 LOC: Config.digest.swapout_chunk_size
7173 This is the number of bytes of the Cache Digest to write to
7174 disk at a time. It defaults to 4096 bytes (4KB), the Squid
7178 NAME: digest_rebuild_chunk_percentage
7179 COMMENT: (percent, 0-100)
7180 IFDEF: USE_CACHE_DIGESTS
7182 LOC: Config.digest.rebuild_chunk_percentage
7185 This is the percentage of the Cache Digest to be scanned at a
7186 time. By default it is set to 10% of the Cache Digest.
7191 -----------------------------------------------------------------------------
7196 LOC: Config.Port.snmp
7198 DEFAULT_DOC: SNMP disabled.
7201 The port number where Squid listens for SNMP requests. To enable
7202 SNMP support set this to a suitable port number. Port number
7203 3401 is often used for the Squid SNMP agent. By default it's
7204 set to "0" (disabled)
7212 LOC: Config.accessList.snmp
7214 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
7217 Allowing or denying access to the SNMP port.
7219 All access to the agent is denied by default.
7222 snmp_access allow|deny [!]aclname ...
7224 This clause only supports fast acl types.
7225 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7228 snmp_access allow snmppublic localhost
7229 snmp_access deny all
7232 NAME: snmp_incoming_address
7234 LOC: Config.Addrs.snmp_incoming
7236 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
7239 Just like 'udp_incoming_address', but for the SNMP port.
7241 snmp_incoming_address is used for the SNMP socket receiving
7242 messages from SNMP agents.
7244 The default snmp_incoming_address is to listen on all
7245 available network interfaces.
7248 NAME: snmp_outgoing_address
7250 LOC: Config.Addrs.snmp_outgoing
7252 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
7255 Just like 'udp_outgoing_address', but for the SNMP port.
7257 snmp_outgoing_address is used for SNMP packets returned to SNMP
7260 If snmp_outgoing_address is not set it will use the same socket
7261 as snmp_incoming_address. Only change this if you want to have
7262 SNMP replies sent using another address than where this Squid
7263 listens for SNMP queries.
7265 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
7266 the same value since they both use the same port.
7271 -----------------------------------------------------------------------------
7274 NAME: icp_port udp_port
7277 DEFAULT_DOC: ICP disabled.
7278 LOC: Config.Port.icp
7280 The port number where Squid sends and receives ICP queries to
7281 and from neighbor caches. The standard UDP port for ICP is 3130.
7284 icp_port @DEFAULT_ICP_PORT@
7291 DEFAULT_DOC: HTCP disabled.
7292 LOC: Config.Port.htcp
7294 The port number where Squid sends and receives HTCP queries to
7295 and from neighbor caches. To turn it on you want to set it to
7302 NAME: log_icp_queries
7306 LOC: Config.onoff.log_udp
7308 If set, ICP queries are logged to access.log. You may wish
7309 do disable this if your ICP load is VERY high to speed things
7310 up or to simplify log analysis.
7313 NAME: udp_incoming_address
7315 LOC:Config.Addrs.udp_incoming
7317 DEFAULT_DOC: Accept packets from all machine interfaces.
7319 udp_incoming_address is used for UDP packets received from other
7322 The default behavior is to not bind to any specific address.
7324 Only change this if you want to have all UDP queries received on
7325 a specific interface/address.
7327 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
7328 modules. Altering it will affect all of them in the same manner.
7330 see also; udp_outgoing_address
7332 NOTE, udp_incoming_address and udp_outgoing_address can not
7333 have the same value since they both use the same port.
7336 NAME: udp_outgoing_address
7338 LOC: Config.Addrs.udp_outgoing
7340 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
7342 udp_outgoing_address is used for UDP packets sent out to other
7345 The default behavior is to not bind to any specific address.
7347 Instead it will use the same socket as udp_incoming_address.
7348 Only change this if you want to have UDP queries sent using another
7349 address than where this Squid listens for UDP queries from other
7352 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7353 modules. Altering it will affect all of them in the same manner.
7355 see also; udp_incoming_address
7357 NOTE, udp_incoming_address and udp_outgoing_address can not
7358 have the same value since they both use the same port.
7365 LOC: Config.onoff.icp_hit_stale
7367 If you want to return ICP_HIT for stale cache objects, set this
7368 option to 'on'. If you have sibling relationships with caches
7369 in other administrative domains, this should be 'off'. If you only
7370 have sibling relationships with caches under your control,
7371 it is probably okay to set this to 'on'.
7372 If set to 'on', your siblings should use the option "allow-miss"
7373 on their cache_peer lines for connecting to you.
7376 NAME: minimum_direct_hops
7379 LOC: Config.minDirectHops
7381 If using the ICMP pinging stuff, do direct fetches for sites
7382 which are no more than this many hops away.
7385 NAME: minimum_direct_rtt
7389 LOC: Config.minDirectRtt
7391 If using the ICMP pinging stuff, do direct fetches for sites
7392 which are no more than this many rtt milliseconds away.
7398 LOC: Config.Netdb.low
7400 The low water mark for the ICMP measurement database.
7402 Note: high watermark controlled by netdb_high directive.
7404 These watermarks are counts, not percents. The defaults are
7405 (low) 900 and (high) 1000. When the high water mark is
7406 reached, database entries will be deleted until the low
7413 LOC: Config.Netdb.high
7415 The high water mark for the ICMP measurement database.
7417 Note: low watermark controlled by netdb_low directive.
7419 These watermarks are counts, not percents. The defaults are
7420 (low) 900 and (high) 1000. When the high water mark is
7421 reached, database entries will be deleted until the low
7425 NAME: netdb_ping_period
7427 LOC: Config.Netdb.period
7430 The minimum period for measuring a site. There will be at
7431 least this much delay between successive pings to the same
7432 network. The default is five minutes.
7439 LOC: Config.onoff.query_icmp
7441 If you want to ask your peers to include ICMP data in their ICP
7442 replies, enable this option.
7444 If your peer has configured Squid (during compilation) with
7445 '--enable-icmp' that peer will send ICMP pings to origin server
7446 sites of the URLs it receives. If you enable this option the
7447 ICP replies from that peer will include the ICMP data (if available).
7448 Then, when choosing a parent cache, Squid will choose the parent with
7449 the minimal RTT to the origin server. When this happens, the
7450 hierarchy field of the access.log will be
7451 "CLOSEST_PARENT_MISS". This option is off by default.
7454 NAME: test_reachability
7458 LOC: Config.onoff.test_reachability
7460 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
7461 instead of ICP_MISS if the target host is NOT in the ICMP
7462 database, or has a zero RTT.
7465 NAME: icp_query_timeout
7468 DEFAULT_DOC: Dynamic detection.
7470 LOC: Config.Timeout.icp_query
7472 Normally Squid will automatically determine an optimal ICP
7473 query timeout value based on the round-trip-time of recent ICP
7474 queries. If you want to override the value determined by
7475 Squid, set this 'icp_query_timeout' to a non-zero value. This
7476 value is specified in MILLISECONDS, so, to use a 2-second
7477 timeout (the old default), you would write:
7479 icp_query_timeout 2000
7482 NAME: maximum_icp_query_timeout
7486 LOC: Config.Timeout.icp_query_max
7488 Normally the ICP query timeout is determined dynamically. But
7489 sometimes it can lead to very large values (say 5 seconds).
7490 Use this option to put an upper limit on the dynamic timeout
7491 value. Do NOT use this option to always use a fixed (instead
7492 of a dynamic) timeout value. To set a fixed timeout see the
7493 'icp_query_timeout' directive.
7496 NAME: minimum_icp_query_timeout
7500 LOC: Config.Timeout.icp_query_min
7502 Normally the ICP query timeout is determined dynamically. But
7503 sometimes it can lead to very small timeouts, even lower than
7504 the normal latency variance on your link due to traffic.
7505 Use this option to put an lower limit on the dynamic timeout
7506 value. Do NOT use this option to always use a fixed (instead
7507 of a dynamic) timeout value. To set a fixed timeout see the
7508 'icp_query_timeout' directive.
7511 NAME: background_ping_rate
7515 LOC: Config.backgroundPingRate
7517 Controls how often the ICP pings are sent to siblings that
7518 have background-ping set.
7522 MULTICAST ICP OPTIONS
7523 -----------------------------------------------------------------------------
7528 LOC: Config.mcast_group_list
7531 This tag specifies a list of multicast groups which your server
7532 should join to receive multicasted ICP queries.
7534 NOTE! Be very careful what you put here! Be sure you
7535 understand the difference between an ICP _query_ and an ICP
7536 _reply_. This option is to be set only if you want to RECEIVE
7537 multicast queries. Do NOT set this option to SEND multicast
7538 ICP (use cache_peer for that). ICP replies are always sent via
7539 unicast, so this option does not affect whether or not you will
7540 receive replies from multicast group members.
7542 You must be very careful to NOT use a multicast address which
7543 is already in use by another group of caches.
7545 If you are unsure about multicast, please read the Multicast
7546 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7548 Usage: mcast_groups 239.128.16.128 224.0.1.20
7550 By default, Squid doesn't listen on any multicast groups.
7553 NAME: mcast_miss_addr
7554 IFDEF: MULTICAST_MISS_STREAM
7556 LOC: Config.mcast_miss.addr
7558 DEFAULT_DOC: disabled.
7560 If you enable this option, every "cache miss" URL will
7561 be sent out on the specified multicast address.
7563 Do not enable this option unless you are are absolutely
7564 certain you understand what you are doing.
7567 NAME: mcast_miss_ttl
7568 IFDEF: MULTICAST_MISS_STREAM
7570 LOC: Config.mcast_miss.ttl
7573 This is the time-to-live value for packets multicasted
7574 when multicasting off cache miss URLs is enabled. By
7575 default this is set to 'site scope', i.e. 16.
7578 NAME: mcast_miss_port
7579 IFDEF: MULTICAST_MISS_STREAM
7581 LOC: Config.mcast_miss.port
7584 This is the port number to be used in conjunction with
7588 NAME: mcast_miss_encode_key
7589 IFDEF: MULTICAST_MISS_STREAM
7591 LOC: Config.mcast_miss.encode_key
7592 DEFAULT: XXXXXXXXXXXXXXXX
7594 The URLs that are sent in the multicast miss stream are
7595 encrypted. This is the encryption key.
7598 NAME: mcast_icp_query_timeout
7602 LOC: Config.Timeout.mcast_icp_query
7604 For multicast peers, Squid regularly sends out ICP "probes" to
7605 count how many other peers are listening on the given multicast
7606 address. This value specifies how long Squid should wait to
7607 count all the replies. The default is 2000 msec, or 2
7612 INTERNAL ICON OPTIONS
7613 -----------------------------------------------------------------------------
7616 NAME: icon_directory
7618 LOC: Config.icons.directory
7619 DEFAULT: @DEFAULT_ICON_DIR@
7621 Where the icons are stored. These are normally kept in
7625 NAME: global_internal_static
7627 LOC: Config.onoff.global_internal_static
7630 This directive controls is Squid should intercept all requests for
7631 /squid-internal-static/ no matter which host the URL is requesting
7632 (default on setting), or if nothing special should be done for
7633 such URLs (off setting). The purpose of this directive is to make
7634 icons etc work better in complex cache hierarchies where it may
7635 not always be possible for all corners in the cache mesh to reach
7636 the server generating a directory listing.
7639 NAME: short_icon_urls
7641 LOC: Config.icons.use_short_names
7644 If this is enabled Squid will use short URLs for icons.
7645 If disabled it will revert to the old behavior of including
7646 it's own name and port in the URL.
7648 If you run a complex cache hierarchy with a mix of Squid and
7649 other proxies you may need to disable this directive.
7654 -----------------------------------------------------------------------------
7657 NAME: error_directory
7659 LOC: Config.errorDirectory
7661 DEFAULT_DOC: Send error pages in the clients preferred language
7663 If you wish to create your own versions of the default
7664 error files to customize them to suit your company copy
7665 the error/template files to another directory and point
7668 WARNING: This option will disable multi-language support
7669 on error pages if used.
7671 The squid developers are interested in making squid available in
7672 a wide variety of languages. If you are making translations for a
7673 language that Squid does not currently provide please consider
7674 contributing your translation back to the project.
7675 http://wiki.squid-cache.org/Translations
7677 The squid developers working on translations are happy to supply drop-in
7678 translated error files in exchange for any new language contributions.
7681 NAME: error_default_language
7682 IFDEF: USE_ERR_LOCALES
7684 LOC: Config.errorDefaultLanguage
7686 DEFAULT_DOC: Generate English language pages.
7688 Set the default language which squid will send error pages in
7689 if no existing translation matches the clients language
7692 If unset (default) generic English will be used.
7694 The squid developers are interested in making squid available in
7695 a wide variety of languages. If you are interested in making
7696 translations for any language see the squid wiki for details.
7697 http://wiki.squid-cache.org/Translations
7700 NAME: error_log_languages
7701 IFDEF: USE_ERR_LOCALES
7703 LOC: Config.errorLogMissingLanguages
7706 Log to cache.log what languages users are attempting to
7707 auto-negotiate for translations.
7709 Successful negotiations are not logged. Only failures
7710 have meaning to indicate that Squid may need an upgrade
7711 of its error page translations.
7714 NAME: err_page_stylesheet
7716 LOC: Config.errorStylesheet
7717 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7719 CSS Stylesheet to pattern the display of Squid default error pages.
7721 For information on CSS see http://www.w3.org/Style/CSS/
7726 LOC: Config.errHtmlText
7729 HTML text to include in error messages. Make this a "mailto"
7730 URL to your admin address, or maybe just a link to your
7731 organizations Web page.
7733 To include this in your error messages, you must rewrite
7734 the error template files (found in the "errors" directory).
7735 Wherever you want the 'err_html_text' line to appear,
7736 insert a %L tag in the error template file.
7739 NAME: email_err_data
7742 LOC: Config.onoff.emailErrData
7745 If enabled, information about the occurred error will be
7746 included in the mailto links of the ERR pages (if %W is set)
7747 so that the email body contains the data.
7748 Syntax is <A HREF="mailto:%w%W">%w</A>
7753 LOC: Config.denyInfoList
7756 Usage: deny_info err_page_name acl
7757 or deny_info http://... acl
7758 or deny_info TCP_RESET acl
7760 This can be used to return a ERR_ page for requests which
7761 do not pass the 'http_access' rules. Squid remembers the last
7762 acl it evaluated in http_access, and if a 'deny_info' line exists
7763 for that ACL Squid returns a corresponding error page.
7765 The acl is typically the last acl on the http_access deny line which
7766 denied access. The exceptions to this rule are:
7767 - When Squid needs to request authentication credentials. It's then
7768 the first authentication related acl encountered
7769 - When none of the http_access lines matches. It's then the last
7770 acl processed on the last http_access line.
7771 - When the decision to deny access was made by an adaptation service,
7772 the acl name is the corresponding eCAP or ICAP service_name.
7774 NP: If providing your own custom error pages with error_directory
7775 you may also specify them by your custom file name:
7776 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7778 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7779 may be specified by prefixing the file name with the code and a colon.
7780 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7782 Alternatively you can tell Squid to reset the TCP connection
7783 by specifying TCP_RESET.
7785 Or you can specify an error URL or URL pattern. The browsers will
7786 get redirected to the specified URL after formatting tags have
7787 been replaced. Redirect will be done with 302 or 307 according to
7788 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7789 the URL. e.g. 303:http://example.com/
7792 %a - username (if available. Password NOT included)
7795 %E - Error description
7797 %H - Request domain name
7798 %i - Client IP Address
7800 %o - Message result from external ACL helper
7801 %p - Request Port number
7802 %P - Request Protocol name
7803 %R - Request URL path
7804 %T - Timestamp in RFC 1123 format
7805 %U - Full canonical URL from client
7806 (HTTPS URLs terminate with *)
7807 %u - Full canonical URL from client
7808 %w - Admin email from squid.conf
7810 %% - Literal percent (%) code
7815 OPTIONS INFLUENCING REQUEST FORWARDING
7816 -----------------------------------------------------------------------------
7819 NAME: nonhierarchical_direct
7821 LOC: Config.onoff.nonhierarchical_direct
7824 By default, Squid will send any non-hierarchical requests
7825 (not cacheable request type) direct to origin servers.
7827 When this is set to "off", Squid will prefer to send these
7828 requests to parents.
7830 Note that in most configurations, by turning this off you will only
7831 add latency to these request without any improvement in global hit
7834 This option only sets a preference. If the parent is unavailable a
7835 direct connection to the origin server may still be attempted. To
7836 completely prevent direct connections use never_direct.
7841 LOC: Config.onoff.prefer_direct
7844 Normally Squid tries to use parents for most requests. If you for some
7845 reason like it to first try going direct and only use a parent if
7846 going direct fails set this to on.
7848 By combining nonhierarchical_direct off and prefer_direct on you
7849 can set up Squid to use a parent as a backup path if going direct
7852 Note: If you want Squid to use parents for all requests see
7853 the never_direct directive. prefer_direct only modifies how Squid
7854 acts on cacheable requests.
7857 NAME: cache_miss_revalidate
7861 LOC: Config.onoff.cache_miss_revalidate
7863 RFC 7232 defines a conditional request mechanism to prevent
7864 response objects being unnecessarily transferred over the network.
7865 If that mechanism is used by the client and a cache MISS occurs
7866 it can prevent new cache entries being created.
7868 This option determines whether Squid on cache MISS will pass the
7869 client revalidation request to the server or tries to fetch new
7870 content for caching. It can be useful while the cache is mostly
7871 empty to more quickly have the cache populated by generating
7872 non-conditional GETs.
7874 When set to 'on' (default), Squid will pass all client If-* headers
7875 to the server. This permits server responses without a cacheable
7876 payload to be delivered and on MISS no new cache entry is created.
7878 When set to 'off' and if the request is cacheable, Squid will
7879 remove the clients If-Modified-Since and If-None-Match headers from
7880 the request sent to the server. This requests a 200 status response
7881 from the server to create a new cache entry with.
7886 LOC: Config.accessList.AlwaysDirect
7888 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7890 Usage: always_direct allow|deny [!]aclname ...
7892 Here you can use ACL elements to specify requests which should
7893 ALWAYS be forwarded by Squid to the origin servers without using
7894 any peers. For example, to always directly forward requests for
7895 local servers ignoring any parents or siblings you may have use
7898 acl local-servers dstdomain my.domain.net
7899 always_direct allow local-servers
7901 To always forward FTP requests directly, use
7904 always_direct allow FTP
7906 NOTE: There is a similar, but opposite option named
7907 'never_direct'. You need to be aware that "always_direct deny
7908 foo" is NOT the same thing as "never_direct allow foo". You
7909 may need to use a deny rule to exclude a more-specific case of
7910 some other rule. Example:
7912 acl local-external dstdomain external.foo.net
7913 acl local-servers dstdomain .foo.net
7914 always_direct deny local-external
7915 always_direct allow local-servers
7917 NOTE: If your goal is to make the client forward the request
7918 directly to the origin server bypassing Squid then this needs
7919 to be done in the client configuration. Squid configuration
7920 can only tell Squid how Squid should fetch the object.
7922 NOTE: This directive is not related to caching. The replies
7923 is cached as usual even if you use always_direct. To not cache
7924 the replies see the 'cache' directive.
7926 This clause supports both fast and slow acl types.
7927 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7932 LOC: Config.accessList.NeverDirect
7934 DEFAULT_DOC: Allow DNS results to be used for this request.
7936 Usage: never_direct allow|deny [!]aclname ...
7938 never_direct is the opposite of always_direct. Please read
7939 the description for always_direct if you have not already.
7941 With 'never_direct' you can use ACL elements to specify
7942 requests which should NEVER be forwarded directly to origin
7943 servers. For example, to force the use of a proxy for all
7944 requests, except those in your local domain use something like:
7946 acl local-servers dstdomain .foo.net
7947 never_direct deny local-servers
7948 never_direct allow all
7950 or if Squid is inside a firewall and there are local intranet
7951 servers inside the firewall use something like:
7953 acl local-intranet dstdomain .foo.net
7954 acl local-external dstdomain external.foo.net
7955 always_direct deny local-external
7956 always_direct allow local-intranet
7957 never_direct allow all
7959 This clause supports both fast and slow acl types.
7960 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7964 ADVANCED NETWORKING OPTIONS
7965 -----------------------------------------------------------------------------
7968 NAME: incoming_udp_average incoming_icp_average
7971 LOC: Config.comm_incoming.udp.average
7973 Heavy voodoo here. I can't even believe you are reading this.
7974 Are you crazy? Don't even think about adjusting these unless
7975 you understand the algorithms in comm_select.c first!
7978 NAME: incoming_tcp_average incoming_http_average
7981 LOC: Config.comm_incoming.tcp.average
7983 Heavy voodoo here. I can't even believe you are reading this.
7984 Are you crazy? Don't even think about adjusting these unless
7985 you understand the algorithms in comm_select.c first!
7988 NAME: incoming_dns_average
7991 LOC: Config.comm_incoming.dns.average
7993 Heavy voodoo here. I can't even believe you are reading this.
7994 Are you crazy? Don't even think about adjusting these unless
7995 you understand the algorithms in comm_select.c first!
7998 NAME: min_udp_poll_cnt min_icp_poll_cnt
8001 LOC: Config.comm_incoming.udp.min_poll
8003 Heavy voodoo here. I can't even believe you are reading this.
8004 Are you crazy? Don't even think about adjusting these unless
8005 you understand the algorithms in comm_select.c first!
8008 NAME: min_dns_poll_cnt
8011 LOC: Config.comm_incoming.dns.min_poll
8013 Heavy voodoo here. I can't even believe you are reading this.
8014 Are you crazy? Don't even think about adjusting these unless
8015 you understand the algorithms in comm_select.c first!
8018 NAME: min_tcp_poll_cnt min_http_poll_cnt
8021 LOC: Config.comm_incoming.tcp.min_poll
8023 Heavy voodoo here. I can't even believe you are reading this.
8024 Are you crazy? Don't even think about adjusting these unless
8025 you understand the algorithms in comm_select.c first!
8031 LOC: Config.accept_filter
8035 The name of an accept(2) filter to install on Squid's
8036 listen socket(s). This feature is perhaps specific to
8037 FreeBSD and requires support in the kernel.
8039 The 'httpready' filter delays delivering new connections
8040 to Squid until a full HTTP request has been received.
8041 See the accf_http(9) man page for details.
8043 The 'dataready' filter delays delivering new connections
8044 to Squid until there is some data to process.
8045 See the accf_dataready(9) man page for details.
8049 The 'data' filter delays delivering of new connections
8050 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
8051 You may optionally specify a number of seconds to wait by
8052 'data=N' where N is the number of seconds. Defaults to 30
8053 if not specified. See the tcp(7) man page for details.
8056 accept_filter httpready
8061 NAME: client_ip_max_connections
8063 LOC: Config.client_ip_max_connections
8065 DEFAULT_DOC: No limit.
8067 Set an absolute limit on the number of connections a single
8068 client IP can use. Any more than this and Squid will begin to drop
8069 new connections from the client until it closes some links.
8071 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
8072 connections from the client. For finer control use the ACL access controls.
8074 Requires client_db to be enabled (the default).
8076 WARNING: This may noticably slow down traffic received via external proxies
8077 or NAT devices and cause them to rebound error messages back to their clients.
8080 NAME: tcp_recv_bufsize
8084 DEFAULT_DOC: Use operating system TCP defaults.
8085 LOC: Config.tcpRcvBufsz
8087 Size of receive buffer to set for TCP sockets. Probably just
8088 as easy to change your kernel's default.
8089 Omit from squid.conf to use the default buffer size.
8094 -----------------------------------------------------------------------------
8101 LOC: Adaptation::Icap::TheConfig.onoff
8104 If you want to enable the ICAP module support, set this to on.
8107 NAME: icap_connect_timeout
8110 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
8113 This parameter specifies how long to wait for the TCP connect to
8114 the requested ICAP server to complete before giving up and either
8115 terminating the HTTP transaction or bypassing the failure.
8117 The default for optional services is peer_connect_timeout.
8118 The default for essential services is connect_timeout.
8119 If this option is explicitly set, its value applies to all services.
8122 NAME: icap_io_timeout
8126 DEFAULT_DOC: Use read_timeout.
8127 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
8130 This parameter specifies how long to wait for an I/O activity on
8131 an established, active ICAP connection before giving up and
8132 either terminating the HTTP transaction or bypassing the
8136 NAME: icap_service_failure_limit
8137 COMMENT: limit [in memory-depth time-units]
8138 TYPE: icap_service_failure_limit
8140 LOC: Adaptation::Icap::TheConfig
8143 The limit specifies the number of failures that Squid tolerates
8144 when establishing a new TCP connection with an ICAP service. If
8145 the number of failures exceeds the limit, the ICAP service is
8146 not used for new ICAP requests until it is time to refresh its
8149 A negative value disables the limit. Without the limit, an ICAP
8150 service will not be considered down due to connectivity failures
8151 between ICAP OPTIONS requests.
8153 Squid forgets ICAP service failures older than the specified
8154 value of memory-depth. The memory fading algorithm
8155 is approximate because Squid does not remember individual
8156 errors but groups them instead, splitting the option
8157 value into ten time slots of equal length.
8159 When memory-depth is 0 and by default this option has no
8160 effect on service failure expiration.
8162 Squid always forgets failures when updating service settings
8163 using an ICAP OPTIONS transaction, regardless of this option
8167 # suspend service usage after 10 failures in 5 seconds:
8168 icap_service_failure_limit 10 in 5 seconds
8171 NAME: icap_service_revival_delay
8174 LOC: Adaptation::Icap::TheConfig.service_revival_delay
8177 The delay specifies the number of seconds to wait after an ICAP
8178 OPTIONS request failure before requesting the options again. The
8179 failed ICAP service is considered "down" until fresh OPTIONS are
8182 The actual delay cannot be smaller than the hardcoded minimum
8183 delay of 30 seconds.
8186 NAME: icap_preview_enable
8190 LOC: Adaptation::Icap::TheConfig.preview_enable
8193 The ICAP Preview feature allows the ICAP server to handle the
8194 HTTP message by looking only at the beginning of the message body
8195 or even without receiving the body at all. In some environments,
8196 previews greatly speedup ICAP processing.
8198 During an ICAP OPTIONS transaction, the server may tell Squid what
8199 HTTP messages should be previewed and how big the preview should be.
8200 Squid will not use Preview if the server did not request one.
8202 To disable ICAP Preview for all ICAP services, regardless of
8203 individual ICAP server OPTIONS responses, set this option to "off".
8205 icap_preview_enable off
8208 NAME: icap_preview_size
8211 LOC: Adaptation::Icap::TheConfig.preview_size
8213 DEFAULT_DOC: No preview sent.
8215 The default size of preview data to be sent to the ICAP server.
8216 This value might be overwritten on a per server basis by OPTIONS requests.
8219 NAME: icap_206_enable
8223 LOC: Adaptation::Icap::TheConfig.allow206_enable
8226 206 (Partial Content) responses is an ICAP extension that allows the
8227 ICAP agents to optionally combine adapted and original HTTP message
8228 content. The decision to combine is postponed until the end of the
8229 ICAP response. Squid supports Partial Content extension by default.
8231 Activation of the Partial Content extension is negotiated with each
8232 ICAP service during OPTIONS exchange. Most ICAP servers should handle
8233 negotation correctly even if they do not support the extension, but
8234 some might fail. To disable Partial Content support for all ICAP
8235 services and to avoid any negotiation, set this option to "off".
8241 NAME: icap_default_options_ttl
8244 LOC: Adaptation::Icap::TheConfig.default_options_ttl
8247 The default TTL value for ICAP OPTIONS responses that don't have
8248 an Options-TTL header.
8251 NAME: icap_persistent_connections
8255 LOC: Adaptation::Icap::TheConfig.reuse_connections
8258 Whether or not Squid should use persistent connections to
8262 NAME: adaptation_send_client_ip icap_send_client_ip
8264 IFDEF: USE_ADAPTATION
8266 LOC: Adaptation::Config::send_client_ip
8269 If enabled, Squid shares HTTP client IP information with adaptation
8270 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
8271 For eCAP, Squid sets the libecap::metaClientIp transaction option.
8273 See also: adaptation_uses_indirect_client
8276 NAME: adaptation_send_username icap_send_client_username
8278 IFDEF: USE_ADAPTATION
8280 LOC: Adaptation::Config::send_username
8283 This sends authenticated HTTP client username (if available) to
8284 the adaptation service.
8286 For ICAP, the username value is encoded based on the
8287 icap_client_username_encode option and is sent using the header
8288 specified by the icap_client_username_header option.
8291 NAME: icap_client_username_header
8294 LOC: Adaptation::Icap::TheConfig.client_username_header
8295 DEFAULT: X-Client-Username
8297 ICAP request header name to use for adaptation_send_username.
8300 NAME: icap_client_username_encode
8304 LOC: Adaptation::Icap::TheConfig.client_username_encode
8307 Whether to base64 encode the authenticated client username.
8311 TYPE: icap_service_type
8313 LOC: Adaptation::Icap::TheConfig
8316 Defines a single ICAP service using the following format:
8318 icap_service id vectoring_point uri [option ...]
8321 an opaque identifier or name which is used to direct traffic to
8322 this specific service. Must be unique among all adaptation
8323 services in squid.conf.
8325 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8326 This specifies at which point of transaction processing the
8327 ICAP service should be activated. *_postcache vectoring points
8328 are not yet supported.
8330 uri: icap://servername:port/servicepath
8331 ICAP server and service location.
8332 icaps://servername:port/servicepath
8333 The "icap:" URI scheme is used for traditional ICAP server and
8334 service location (default port is 1344, connections are not
8335 encrypted). The "icaps:" URI scheme is for Secure ICAP
8336 services that use SSL/TLS-encrypted ICAP connections (by
8337 default, on port 11344).
8339 ICAP does not allow a single service to handle both REQMOD and RESPMOD
8340 transactions. Squid does not enforce that requirement. You can specify
8341 services with the same service_url and different vectoring_points. You
8342 can even specify multiple identical services as long as their
8343 service_names differ.
8345 To activate a service, use the adaptation_access directive. To group
8346 services, use adaptation_service_chain and adaptation_service_set.
8348 Service options are separated by white space. ICAP services support
8349 the following name=value options:
8352 If set to 'on' or '1', the ICAP service is treated as
8353 optional. If the service cannot be reached or malfunctions,
8354 Squid will try to ignore any errors and process the message as
8355 if the service was not enabled. No all ICAP errors can be
8356 bypassed. If set to 0, the ICAP service is treated as
8357 essential and all ICAP errors will result in an error page
8358 returned to the HTTP client.
8360 Bypass is off by default: services are treated as essential.
8363 If set to 'on' or '1', the ICAP service is allowed to
8364 dynamically change the current message adaptation plan by
8365 returning a chain of services to be used next. The services
8366 are specified using the X-Next-Services ICAP response header
8367 value, formatted as a comma-separated list of service names.
8368 Each named service should be configured in squid.conf. Other
8369 services are ignored. An empty X-Next-Services value results
8370 in an empty plan which ends the current adaptation.
8372 Dynamic adaptation plan may cross or cover multiple supported
8373 vectoring points in their natural processing order.
8375 Routing is not allowed by default: the ICAP X-Next-Services
8376 response header is ignored.
8379 Only has effect on split-stack systems. The default on those systems
8380 is to use IPv4-only connections. When set to 'on' this option will
8381 make Squid use IPv6-only connections to contact this ICAP service.
8383 on-overload=block|bypass|wait|force
8384 If the service Max-Connections limit has been reached, do
8385 one of the following for each new ICAP transaction:
8386 * block: send an HTTP error response to the client
8387 * bypass: ignore the "over-connected" ICAP service
8388 * wait: wait (in a FIFO queue) for an ICAP connection slot
8389 * force: proceed, ignoring the Max-Connections limit
8391 In SMP mode with N workers, each worker assumes the service
8392 connection limit is Max-Connections/N, even though not all
8393 workers may use a given service.
8395 The default value is "bypass" if service is bypassable,
8396 otherwise it is set to "wait".
8400 Use the given number as the Max-Connections limit, regardless
8401 of the Max-Connections value given by the service, if any.
8403 ==== ICAPS / TLS OPTIONS ====
8405 These options are used for Secure ICAP (icaps://....) services only.
8407 tls-cert=/path/to/ssl/certificate
8408 A client SSL certificate to use when connecting to
8411 tls-key=/path/to/ssl/key
8412 The private TLS/SSL key corresponding to sslcert above.
8413 If 'tls-key' is not specified 'tls-cert' is assumed to
8414 reference a combined PEM format file containing both the
8415 certificate and the key.
8417 tls-cipher=... The list of valid TLS/SSL ciphers to use when connecting
8418 to this icap server.
8421 The minimum TLS protocol version to permit. To control
8422 SSLv3 use the ssloptions= parameter.
8423 Supported Values: 1.0 (default), 1.1, 1.2
8425 tls-options=... Specify various OpenSSL library options:
8427 NO_SSLv3 Disallow the use of SSLv3
8429 NO_TLSv1 Disallow the use of TLSv1.0
8430 NO_TLSv1_1 Disallow the use of TLSv1.1
8431 NO_TLSv1_2 Disallow the use of TLSv1.2
8434 Always create a new key when using
8435 temporary/ephemeral DH key exchanges
8437 ALL Enable various bug workarounds
8438 suggested as "harmless" by OpenSSL
8439 Be warned that this reduces SSL/TLS
8440 strength to some attacks.
8442 See the OpenSSL SSL_CTX_set_options documentation for a
8443 more complete list. Options relevant only to SSLv2 are
8446 tls-cafile= PEM file containing CA certificates to use when verifying
8447 the icap server certificate.
8448 Use to specify intermediate CA certificate(s) if not sent
8449 by the server. Or the full CA chain for the server when
8450 using the tls-no-default-ca flag.
8451 May be repeated to load multiple files.
8453 tls-capath=... A directory containing additional CA certificates to
8454 use when verifying the icap server certificate.
8455 Requires OpenSSL or LibreSSL.
8457 tls-crlfile=... A certificate revocation list file to use when
8458 verifying the icap server certificate.
8460 tls-flags=... Specify various flags modifying the Squid TLS implementation:
8463 Accept certificates even if they fail to
8466 Don't verify the icap server certificate
8467 matches the server name
8470 Do no use the system default Trusted CA.
8472 tls-domain= The icap server name as advertised in it's certificate.
8473 Used for verifying the correctness of the received icap
8474 server certificate. If not specified the icap server
8475 hostname extracted from ICAP URI will be used.
8477 Older icap_service format without optional named parameters is
8478 deprecated but supported for backward compatibility.
8481 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
8482 icap_service svcLogger reqmod_precache icaps://icap2.mydomain.net:11344/reqmod routing=on
8486 TYPE: icap_class_type
8491 This deprecated option was documented to define an ICAP service
8492 chain, even though it actually defined a set of similar, redundant
8493 services, and the chains were not supported.
8495 To define a set of redundant services, please use the
8496 adaptation_service_set directive. For service chains, use
8497 adaptation_service_chain.
8501 TYPE: icap_access_type
8506 This option is deprecated. Please use adaptation_access, which
8507 has the same ICAP functionality, but comes with better
8508 documentation, and eCAP support.
8513 -----------------------------------------------------------------------------
8520 LOC: Adaptation::Ecap::TheConfig.onoff
8523 Controls whether eCAP support is enabled.
8527 TYPE: ecap_service_type
8529 LOC: Adaptation::Ecap::TheConfig
8532 Defines a single eCAP service
8534 ecap_service id vectoring_point uri [option ...]
8537 an opaque identifier or name which is used to direct traffic to
8538 this specific service. Must be unique among all adaptation
8539 services in squid.conf.
8541 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8542 This specifies at which point of transaction processing the
8543 eCAP service should be activated. *_postcache vectoring points
8544 are not yet supported.
8546 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
8547 Squid uses the eCAP service URI to match this configuration
8548 line with one of the dynamically loaded services. Each loaded
8549 eCAP service must have a unique URI. Obtain the right URI from
8550 the service provider.
8552 To activate a service, use the adaptation_access directive. To group
8553 services, use adaptation_service_chain and adaptation_service_set.
8555 Service options are separated by white space. eCAP services support
8556 the following name=value options:
8559 If set to 'on' or '1', the eCAP service is treated as optional.
8560 If the service cannot be reached or malfunctions, Squid will try
8561 to ignore any errors and process the message as if the service
8562 was not enabled. No all eCAP errors can be bypassed.
8563 If set to 'off' or '0', the eCAP service is treated as essential
8564 and all eCAP errors will result in an error page returned to the
8567 Bypass is off by default: services are treated as essential.
8570 If set to 'on' or '1', the eCAP service is allowed to
8571 dynamically change the current message adaptation plan by
8572 returning a chain of services to be used next.
8574 Dynamic adaptation plan may cross or cover multiple supported
8575 vectoring points in their natural processing order.
8577 Routing is not allowed by default.
8579 Older ecap_service format without optional named parameters is
8580 deprecated but supported for backward compatibility.
8584 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
8585 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
8588 NAME: loadable_modules
8590 IFDEF: USE_LOADABLE_MODULES
8591 LOC: Config.loadable_module_names
8594 Instructs Squid to load the specified dynamic module(s) or activate
8595 preloaded module(s).
8597 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
8601 MESSAGE ADAPTATION OPTIONS
8602 -----------------------------------------------------------------------------
8605 NAME: adaptation_service_set
8606 TYPE: adaptation_service_set_type
8607 IFDEF: USE_ADAPTATION
8612 Configures an ordered set of similar, redundant services. This is
8613 useful when hot standby or backup adaptation servers are available.
8615 adaptation_service_set set_name service_name1 service_name2 ...
8617 The named services are used in the set declaration order. The first
8618 applicable adaptation service from the set is used first. The next
8619 applicable service is tried if and only if the transaction with the
8620 previous service fails and the message waiting to be adapted is still
8623 When adaptation starts, broken services are ignored as if they were
8624 not a part of the set. A broken service is a down optional service.
8626 The services in a set must be attached to the same vectoring point
8627 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8629 If all services in a set are optional then adaptation failures are
8630 bypassable. If all services in the set are essential, then a
8631 transaction failure with one service may still be retried using
8632 another service from the set, but when all services fail, the master
8633 transaction fails as well.
8635 A set may contain a mix of optional and essential services, but that
8636 is likely to lead to surprising results because broken services become
8637 ignored (see above), making previously bypassable failures fatal.
8638 Technically, it is the bypassability of the last failed service that
8641 See also: adaptation_access adaptation_service_chain
8644 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
8645 adaptation service_set svcLogger loggerLocal loggerRemote
8648 NAME: adaptation_service_chain
8649 TYPE: adaptation_service_chain_type
8650 IFDEF: USE_ADAPTATION
8655 Configures a list of complementary services that will be applied
8656 one-by-one, forming an adaptation chain or pipeline. This is useful
8657 when Squid must perform different adaptations on the same message.
8659 adaptation_service_chain chain_name service_name1 svc_name2 ...
8661 The named services are used in the chain declaration order. The first
8662 applicable adaptation service from the chain is used first. The next
8663 applicable service is applied to the successful adaptation results of
8664 the previous service in the chain.
8666 When adaptation starts, broken services are ignored as if they were
8667 not a part of the chain. A broken service is a down optional service.
8669 Request satisfaction terminates the adaptation chain because Squid
8670 does not currently allow declaration of RESPMOD services at the
8671 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8673 The services in a chain must be attached to the same vectoring point
8674 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8676 A chain may contain a mix of optional and essential services. If an
8677 essential adaptation fails (or the failure cannot be bypassed for
8678 other reasons), the master transaction fails. Otherwise, the failure
8679 is bypassed as if the failed adaptation service was not in the chain.
8681 See also: adaptation_access adaptation_service_set
8684 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8687 NAME: adaptation_access
8688 TYPE: adaptation_access_type
8689 IFDEF: USE_ADAPTATION
8692 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8694 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8696 adaptation_access service_name allow|deny [!]aclname...
8697 adaptation_access set_name allow|deny [!]aclname...
8699 At each supported vectoring point, the adaptation_access
8700 statements are processed in the order they appear in this
8701 configuration file. Statements pointing to the following services
8702 are ignored (i.e., skipped without checking their ACL):
8704 - services serving different vectoring points
8705 - "broken-but-bypassable" services
8706 - "up" services configured to ignore such transactions
8707 (e.g., based on the ICAP Transfer-Ignore header).
8709 When a set_name is used, all services in the set are checked
8710 using the same rules, to find the first applicable one. See
8711 adaptation_service_set for details.
8713 If an access list is checked and there is a match, the
8714 processing stops: For an "allow" rule, the corresponding
8715 adaptation service is used for the transaction. For a "deny"
8716 rule, no adaptation service is activated.
8718 It is currently not possible to apply more than one adaptation
8719 service at the same vectoring point to the same HTTP transaction.
8721 See also: icap_service and ecap_service
8724 adaptation_access service_1 allow all
8727 NAME: adaptation_service_iteration_limit
8729 IFDEF: USE_ADAPTATION
8730 LOC: Adaptation::Config::service_iteration_limit
8733 Limits the number of iterations allowed when applying adaptation
8734 services to a message. If your longest adaptation set or chain
8735 may have more than 16 services, increase the limit beyond its
8736 default value of 16. If detecting infinite iteration loops sooner
8737 is critical, make the iteration limit match the actual number
8738 of services in your longest adaptation set or chain.
8740 Infinite adaptation loops are most likely with routing services.
8742 See also: icap_service routing=1
8745 NAME: adaptation_masterx_shared_names
8747 IFDEF: USE_ADAPTATION
8748 LOC: Adaptation::Config::masterx_shared_name
8751 For each master transaction (i.e., the HTTP request and response
8752 sequence, including all related ICAP and eCAP exchanges), Squid
8753 maintains a table of metadata. The table entries are (name, value)
8754 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8755 with the master transaction.
8757 This option specifies the table entry names that Squid must accept
8758 from and forward to the adaptation transactions.
8760 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8761 shared table by returning an ICAP header field with a name
8762 specified in adaptation_masterx_shared_names.
8764 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8765 shared table by implementing the libecap::visitEachOption() API
8766 to provide an option with a name specified in
8767 adaptation_masterx_shared_names.
8769 Squid will store and forward the set entry to subsequent adaptation
8770 transactions within the same master transaction scope.
8772 Only one shared entry name is supported at this time.
8775 # share authentication information among ICAP services
8776 adaptation_masterx_shared_names X-Subscriber-ID
8779 NAME: adaptation_meta
8781 IFDEF: USE_ADAPTATION
8782 LOC: Adaptation::Config::metaHeaders
8785 This option allows Squid administrator to add custom ICAP request
8786 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8787 Use it to pass custom authentication tokens and other
8788 transaction-state related meta information to an ICAP/eCAP service.
8790 The addition of a meta header is ACL-driven:
8791 adaptation_meta name value [!]aclname ...
8793 Processing for a given header name stops after the first ACL list match.
8794 Thus, it is impossible to add two headers with the same name. If no ACL
8795 lists match for a given header name, no such header is added. For
8798 # do not debug transactions except for those that need debugging
8799 adaptation_meta X-Debug 1 needs_debugging
8801 # log all transactions except for those that must remain secret
8802 adaptation_meta X-Log 1 !keep_secret
8804 # mark transactions from users in the "G 1" group
8805 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8807 The "value" parameter may be a regular squid.conf token or a "double
8808 quoted string". Within the quoted string, use backslash (\) to escape
8809 any character, which is currently only useful for escaping backslashes
8810 and double quotes. For example,
8811 "this string has one backslash (\\) and two \"quotes\""
8813 Used adaptation_meta header values may be logged via %note
8814 logformat code. If multiple adaptation_meta headers with the same name
8815 are used during master transaction lifetime, the header values are
8816 logged in the order they were used and duplicate values are ignored
8817 (only the first repeated value will be logged).
8823 LOC: Adaptation::Icap::TheConfig.repeat
8824 DEFAULT_IF_NONE: deny all
8826 This ACL determines which retriable ICAP transactions are
8827 retried. Transactions that received a complete ICAP response
8828 and did not have to consume or produce HTTP bodies to receive
8829 that response are usually retriable.
8831 icap_retry allow|deny [!]aclname ...
8833 Squid automatically retries some ICAP I/O timeouts and errors
8834 due to persistent connection race conditions.
8836 See also: icap_retry_limit
8839 NAME: icap_retry_limit
8842 LOC: Adaptation::Icap::TheConfig.repeat_limit
8844 DEFAULT_DOC: No retries are allowed.
8846 Limits the number of retries allowed.
8848 Communication errors due to persistent connection race
8849 conditions are unavoidable, automatically retried, and do not
8850 count against this limit.
8852 See also: icap_retry
8858 -----------------------------------------------------------------------------
8861 NAME: check_hostnames
8864 LOC: Config.onoff.check_hostnames
8866 For security and stability reasons Squid can check
8867 hostnames for Internet standard RFC compliance. If you want
8868 Squid to perform these checks turn this directive on.
8871 NAME: allow_underscore
8874 LOC: Config.onoff.allow_underscore
8876 Underscore characters is not strictly allowed in Internet hostnames
8877 but nevertheless used by many sites. Set this to off if you want
8878 Squid to be strict about the standard.
8879 This check is performed only when check_hostnames is set to on.
8882 NAME: dns_retransmit_interval
8885 LOC: Config.Timeout.idns_retransmit
8887 Initial retransmit interval for DNS queries. The interval is
8888 doubled each time all configured DNS servers have been tried.
8894 LOC: Config.Timeout.idns_query
8896 DNS Query timeout. If no response is received to a DNS query
8897 within this time all DNS servers for the queried domain
8898 are assumed to be unavailable.
8901 NAME: dns_packet_max
8903 DEFAULT_DOC: EDNS disabled
8905 LOC: Config.dns.packet_max
8907 Maximum number of bytes packet size to advertise via EDNS.
8908 Set to "none" to disable EDNS large packet support.
8910 For legacy reasons DNS UDP replies will default to 512 bytes which
8911 is too small for many responses. EDNS provides a means for Squid to
8912 negotiate receiving larger responses back immediately without having
8913 to failover with repeat requests. Responses larger than this limit
8914 will retain the old behaviour of failover to TCP DNS.
8916 Squid has no real fixed limit internally, but allowing packet sizes
8917 over 1500 bytes requires network jumbogram support and is usually not
8920 WARNING: The RFC also indicates that some older resolvers will reply
8921 with failure of the whole request if the extension is added. Some
8922 resolvers have already been identified which will reply with mangled
8923 EDNS response on occasion. Usually in response to many-KB jumbogram
8924 sizes being advertised by Squid.
8925 Squid will currently treat these both as an unable-to-resolve domain
8926 even if it would be resolvable without EDNS.
8933 DEFAULT_DOC: Search for single-label domain names is disabled.
8934 LOC: Config.onoff.res_defnames
8936 Normally the RES_DEFNAMES resolver option is disabled
8937 (see res_init(3)). This prevents caches in a hierarchy
8938 from interpreting single-component hostnames locally. To allow
8939 Squid to handle single-component names, enable this option.
8942 NAME: dns_multicast_local
8946 DEFAULT_DOC: Search for .local and .arpa names is disabled.
8947 LOC: Config.onoff.dns_mdns
8949 When set to on, Squid sends multicast DNS lookups on the local
8950 network for domains ending in .local and .arpa.
8951 This enables local servers and devices to be contacted in an
8952 ad-hoc or zero-configuration network environment.
8955 NAME: dns_nameservers
8958 DEFAULT_DOC: Use operating system definitions
8959 LOC: Config.dns_nameservers
8961 Use this if you want to specify a list of DNS name servers
8962 (IP addresses) to use instead of those given in your
8963 /etc/resolv.conf file.
8965 On Windows platforms, if no value is specified here or in
8966 the /etc/resolv.conf file, the list of DNS name servers are
8967 taken from the Windows registry, both static and dynamic DHCP
8968 configurations are supported.
8970 Example: dns_nameservers 10.0.0.1 192.172.0.4
8975 DEFAULT: @DEFAULT_HOSTS@
8976 LOC: Config.etcHostsPath
8978 Location of the host-local IP name-address associations
8979 database. Most Operating Systems have such a file on different
8981 - Un*X & Linux: /etc/hosts
8982 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
8983 (%SystemRoot% value install default is c:\winnt)
8984 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
8985 (%SystemRoot% value install default is c:\windows)
8986 - Windows 9x/Me: %windir%\hosts
8987 (%windir% value is usually c:\windows)
8988 - Cygwin: /etc/hosts
8990 The file contains newline-separated definitions, in the
8991 form ip_address_in_dotted_form name [name ...] names are
8992 whitespace-separated. Lines beginning with an hash (#)
8993 character are comments.
8995 The file is checked at startup and upon configuration.
8996 If set to 'none', it won't be checked.
8997 If append_domain is used, that domain will be added to
8998 domain-local (i.e. not containing any dot character) host
9004 LOC: Config.appendDomain
9006 DEFAULT_DOC: Use operating system definitions
9008 Appends local domain name to hostnames without any dots in
9009 them. append_domain must begin with a period.
9011 Be warned there are now Internet names with no dots in
9012 them using only top-domain names, so setting this may
9013 cause some Internet sites to become unavailable.
9016 append_domain .yourdomain.com
9019 NAME: ignore_unknown_nameservers
9021 LOC: Config.onoff.ignore_unknown_nameservers
9024 By default Squid checks that DNS responses are received
9025 from the same IP addresses they are sent to. If they
9026 don't match, Squid ignores the response and writes a warning
9027 message to cache.log. You can allow responses from unknown
9028 nameservers by setting this option to 'off'.
9034 LOC: Config.dns.v4_first
9036 With the IPv6 Internet being as fast or faster than IPv4 Internet
9037 for most networks Squid prefers to contact websites over IPv6.
9039 This option reverses the order of preference to make Squid contact
9040 dual-stack websites over IPv4 first. Squid will still perform both
9041 IPv6 and IPv4 DNS lookups before connecting.
9044 This option will restrict the situations under which IPv6
9045 connectivity is used (and tested). Hiding network problems
9046 which would otherwise be detected and warned about.
9050 COMMENT: (number of entries)
9053 LOC: Config.ipcache.size
9055 Maximum number of DNS IP cache entries.
9062 LOC: Config.ipcache.low
9069 LOC: Config.ipcache.high
9071 The size, low-, and high-water marks for the IP cache.
9074 NAME: fqdncache_size
9075 COMMENT: (number of entries)
9078 LOC: Config.fqdncache.size
9080 Maximum number of FQDN cache entries.
9085 -----------------------------------------------------------------------------
9088 NAME: configuration_includes_quoted_values
9090 TYPE: configuration_includes_quoted_values
9092 LOC: ConfigParser::RecognizeQuotedValues
9094 If set, Squid will recognize each "quoted string" after a configuration
9095 directive as a single parameter. The quotes are stripped before the
9096 parameter value is interpreted or used.
9097 See "Values with spaces, quotes, and other special characters"
9098 section for more details.
9105 LOC: Config.onoff.mem_pools
9107 If set, Squid will keep pools of allocated (but unused) memory
9108 available for future use. If memory is a premium on your
9109 system and you believe your malloc library outperforms Squid
9110 routines, disable this.
9113 NAME: memory_pools_limit
9117 LOC: Config.MemPools.limit
9119 Used only with memory_pools on:
9120 memory_pools_limit 50 MB
9122 If set to a non-zero value, Squid will keep at most the specified
9123 limit of allocated (but unused) memory in memory pools. All free()
9124 requests that exceed this limit will be handled by your malloc
9125 library. Squid does not pre-allocate any memory, just safe-keeps
9126 objects that otherwise would be free()d. Thus, it is safe to set
9127 memory_pools_limit to a reasonably high value even if your
9128 configuration will use less memory.
9130 If set to none, Squid will keep all memory it can. That is, there
9131 will be no limit on the total amount of memory used for safe-keeping.
9133 To disable memory allocation optimization, do not set
9134 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
9136 An overhead for maintaining memory pools is not taken into account
9137 when the limit is checked. This overhead is close to four bytes per
9138 object kept. However, pools may actually _save_ memory because of
9139 reduced memory thrashing in your malloc library.
9143 COMMENT: on|off|transparent|truncate|delete
9146 LOC: opt_forwarded_for
9148 If set to "on", Squid will append your client's IP address
9149 in the HTTP requests it forwards. By default it looks like:
9151 X-Forwarded-For: 192.1.2.3
9153 If set to "off", it will appear as
9155 X-Forwarded-For: unknown
9157 If set to "transparent", Squid will not alter the
9158 X-Forwarded-For header in any way.
9160 If set to "delete", Squid will delete the entire
9161 X-Forwarded-For header.
9163 If set to "truncate", Squid will remove all existing
9164 X-Forwarded-For entries, and place the client IP as the sole entry.
9167 NAME: cachemgr_passwd
9168 TYPE: cachemgrpasswd
9170 DEFAULT_DOC: No password. Actions which require password are denied.
9171 LOC: Config.passwd_list
9173 Specify passwords for cachemgr operations.
9175 Usage: cachemgr_passwd password action action ...
9177 Some valid actions are (see cache manager menu for a full list):
9217 * Indicates actions which will not be performed without a
9218 valid password, others can be performed if not listed here.
9220 To disable an action, set the password to "disable".
9221 To allow performing an action without a password, set the
9224 Use the keyword "all" to set the same password for all actions.
9227 cachemgr_passwd secret shutdown
9228 cachemgr_passwd lesssssssecret info stats/objects
9229 cachemgr_passwd disable all
9236 LOC: Config.onoff.client_db
9238 If you want to disable collecting per-client statistics,
9239 turn off client_db here.
9242 NAME: refresh_all_ims
9246 LOC: Config.onoff.refresh_all_ims
9248 When you enable this option, squid will always check
9249 the origin server for an update when a client sends an
9250 If-Modified-Since request. Many browsers use IMS
9251 requests when the user requests a reload, and this
9252 ensures those clients receive the latest version.
9254 By default (off), squid may return a Not Modified response
9255 based on the age of the cached version.
9258 NAME: reload_into_ims
9259 IFDEF: USE_HTTP_VIOLATIONS
9263 LOC: Config.onoff.reload_into_ims
9265 When you enable this option, client no-cache or ``reload''
9266 requests will be changed to If-Modified-Since requests.
9267 Doing this VIOLATES the HTTP standard. Enabling this
9268 feature could make you liable for problems which it
9271 see also refresh_pattern for a more selective approach.
9274 NAME: connect_retries
9276 LOC: Config.connect_retries
9278 DEFAULT_DOC: Do not retry failed connections.
9280 This sets the maximum number of connection attempts made for each
9281 TCP connection. The connect_retries attempts must all still
9282 complete within the connection timeout period.
9284 The default is not to re-try if the first connection attempt fails.
9285 The (not recommended) maximum is 10 tries.
9287 A warning message will be generated if it is set to a too-high
9288 value and the configured value will be over-ridden.
9290 Note: These re-tries are in addition to forward_max_tries
9291 which limit how many different addresses may be tried to find
9295 NAME: retry_on_error
9297 LOC: Config.retry.onerror
9300 If set to ON Squid will automatically retry requests when
9301 receiving an error response with status 403 (Forbidden),
9302 500 (Internal Error), 501 or 503 (Service not available).
9303 Status 502 and 504 (Gateway errors) are always retried.
9305 This is mainly useful if you are in a complex cache hierarchy to
9306 work around access control errors.
9308 NOTE: This retry will attempt to find another working destination.
9309 Which is different from the server which just failed.
9312 NAME: as_whois_server
9314 LOC: Config.as_whois_server
9315 DEFAULT: whois.ra.net
9317 WHOIS server to query for AS numbers. NOTE: AS numbers are
9318 queried only when Squid starts up, not for every request.
9323 LOC: Config.onoff.offline
9326 Enable this option and Squid will never try to validate cached
9330 NAME: uri_whitespace
9331 TYPE: uri_whitespace
9332 LOC: Config.uri_whitespace
9335 What to do with requests that have whitespace characters in the
9338 strip: The whitespace characters are stripped out of the URL.
9339 This is the behavior recommended by RFC2396 and RFC3986
9340 for tolerant handling of generic URI.
9341 NOTE: This is one difference between generic URI and HTTP URLs.
9343 deny: The request is denied. The user receives an "Invalid
9345 This is the behaviour recommended by RFC2616 for safe
9346 handling of HTTP request URL.
9348 allow: The request is allowed and the URI is not changed. The
9349 whitespace characters remain in the URI. Note the
9350 whitespace is passed to redirector processes if they
9352 Note this may be considered a violation of RFC2616
9353 request parsing where whitespace is prohibited in the
9356 encode: The request is allowed and the whitespace characters are
9357 encoded according to RFC1738.
9359 chop: The request is allowed and the URI is chopped at the
9363 NOTE the current Squid implementation of encode and chop violates
9364 RFC2616 by not using a 301 redirect after altering the URL.
9369 LOC: Config.chroot_dir
9372 Specifies a directory where Squid should do a chroot() while
9373 initializing. This also causes Squid to fully drop root
9374 privileges after initializing. This means, for example, if you
9375 use a HTTP port less than 1024 and try to reconfigure, you may
9376 get an error saying that Squid can not open the port.
9379 NAME: balance_on_multiple_ip
9381 LOC: Config.onoff.balance_on_multiple_ip
9384 Modern IP resolvers in squid sort lookup results by preferred access.
9385 By default squid will use these IP in order and only rotates to
9386 the next listed when the most preffered fails.
9388 Some load balancing servers based on round robin DNS have been
9389 found not to preserve user session state across requests
9390 to different IP addresses.
9392 Enabling this directive Squid rotates IP's per request.
9395 NAME: pipeline_prefetch
9396 TYPE: pipelinePrefetch
9397 LOC: Config.pipeline_max_prefetch
9399 DEFAULT_DOC: Do not pre-parse pipelined requests.
9401 HTTP clients may send a pipeline of 1+N requests to Squid using a
9402 single connection, without waiting for Squid to respond to the first
9403 of those requests. This option limits the number of concurrent
9404 requests Squid will try to handle in parallel. If set to N, Squid
9405 will try to receive and process up to 1+N requests on the same
9406 connection concurrently.
9408 Defaults to 0 (off) for bandwidth management and access logging
9411 NOTE: pipelining requires persistent connections to clients.
9413 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
9416 NAME: high_response_time_warning
9419 LOC: Config.warnings.high_rptm
9421 DEFAULT_DOC: disabled.
9423 If the one-minute median response time exceeds this value,
9424 Squid prints a WARNING with debug level 0 to get the
9425 administrators attention. The value is in milliseconds.
9428 NAME: high_page_fault_warning
9430 LOC: Config.warnings.high_pf
9432 DEFAULT_DOC: disabled.
9434 If the one-minute average page fault rate exceeds this
9435 value, Squid prints a WARNING with debug level 0 to get
9436 the administrators attention. The value is in page faults
9440 NAME: high_memory_warning
9442 LOC: Config.warnings.high_memory
9443 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
9445 DEFAULT_DOC: disabled.
9447 If the memory usage (as determined by gnumalloc, if available and used)
9448 exceeds this amount, Squid prints a WARNING with debug level 0 to get
9449 the administrators attention.
9451 # TODO: link high_memory_warning to mempools?
9453 NAME: sleep_after_fork
9454 COMMENT: (microseconds)
9456 LOC: Config.sleep_after_fork
9459 When this is set to a non-zero value, the main Squid process
9460 sleeps the specified number of microseconds after a fork()
9461 system call. This sleep may help the situation where your
9462 system reports fork() failures due to lack of (virtual)
9463 memory. Note, however, if you have a lot of child
9464 processes, these sleep delays will add up and your
9465 Squid will not service requests for some amount of time
9466 until all the child processes have been started.
9467 On Windows value less then 1000 (1 milliseconds) are
9471 NAME: windows_ipaddrchangemonitor
9472 IFDEF: _SQUID_WINDOWS_
9476 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
9478 On Windows Squid by default will monitor IP address changes and will
9479 reconfigure itself after any detected event. This is very useful for
9480 proxies connected to internet with dial-up interfaces.
9481 In some cases (a Proxy server acting as VPN gateway is one) it could be
9482 desiderable to disable this behaviour setting this to 'off'.
9483 Note: after changing this, Squid service must be restarted.
9488 IFDEF: USE_SQUID_EUI
9490 LOC: Eui::TheConfig.euiLookup
9492 Whether to lookup the EUI or MAC address of a connected client.
9495 NAME: max_filedescriptors max_filedesc
9498 DEFAULT_DOC: Use operating system limits set by ulimit.
9499 LOC: Config.max_filedescriptors
9501 Reduce the maximum number of filedescriptors supported below
9502 the usual operating system defaults.
9504 Remove from squid.conf to inherit the current ulimit setting.
9506 Note: Changing this requires a restart of Squid. Also
9507 not all I/O types supports large values (eg on Windows).
9510 NAME: force_request_body_continuation
9512 LOC: Config.accessList.forceRequestBodyContinuation
9514 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
9516 This option controls how Squid handles data upload requests from HTTP
9517 and FTP agents that require a "Please Continue" control message response
9518 to actually send the request body to Squid. It is mostly useful in
9519 adaptation environments.
9521 When Squid receives an HTTP request with an "Expect: 100-continue"
9522 header or an FTP upload command (e.g., STOR), Squid normally sends the
9523 request headers or FTP command information to an adaptation service (or
9524 peer) and waits for a response. Most adaptation services (and some
9525 broken peers) may not respond to Squid at that stage because they may
9526 decide to wait for the HTTP request body or FTP data transfer. However,
9527 that request body or data transfer may never come because Squid has not
9528 responded with the HTTP 100 or FTP 150 (Please Continue) control message
9529 to the request sender yet!
9531 An allow match tells Squid to respond with the HTTP 100 or FTP 150
9532 (Please Continue) control message on its own, before forwarding the
9533 request to an adaptation service or peer. Such a response usually forces
9534 the request sender to proceed with sending the body. A deny match tells
9535 Squid to delay that control response until the origin server confirms
9536 that the request body is needed. Delaying is the default behavior.
projects / thirdparty / squid.git / blob