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 sslcontext= SSL session ID context identifier.
1982 connection-auth[=on|off]
1983 use connection-auth=off to tell Squid to prevent
1984 forwarding Microsoft connection oriented authentication
1985 (NTLM, Negotiate and Kerberos)
1987 disable-pmtu-discovery=
1988 Control Path-MTU discovery usage:
1989 off lets OS decide on what to do (default).
1990 transparent disable PMTU discovery when transparent
1992 always disable always PMTU discovery.
1994 In many setups of transparently intercepting proxies
1995 Path-MTU discovery can not work on traffic towards the
1996 clients. This is the case when the intercepting device
1997 does not fully track connections and fails to forward
1998 ICMP must fragment messages to the cache server. If you
1999 have such setup and experience that certain clients
2000 sporadically hang or never complete requests set
2001 disable-pmtu-discovery option to 'transparent'.
2003 name= Specifies a internal name for the port. Defaults to
2004 the port specification (port or addr:port)
2006 tcpkeepalive[=idle,interval,timeout]
2007 Enable TCP keepalive probes of idle connections.
2008 In seconds; idle is the initial time before TCP starts
2009 probing the connection, interval how often to probe, and
2010 timeout the time before giving up.
2012 require-proxy-header
2013 Require PROXY protocol version 1 or 2 connections.
2014 The proxy_protocol_access is required to whitelist
2015 downstream proxies which can be trusted.
2017 If you run Squid on a dual-homed machine with an internal
2018 and an external interface we recommend you to specify the
2019 internal address:port in http_port. This way Squid will only be
2020 visible on the internal address.
2024 # Squid normally listens to port 3128
2025 http_port @DEFAULT_HTTP_PORT@
2035 Usage: [ip:]port [mode] cert=certificate.pem [options]
2037 The socket address where Squid will listen for client requests made
2038 over TLS or SSL connections. Commonly referred to as HTTPS.
2040 This is most useful for situations where you are running squid in
2041 accelerator mode and you want to do the TLS work at the accelerator level.
2043 You may specify multiple socket addresses on multiple lines,
2044 each with their own certificate and/or options.
2046 The TLS cert= option is mandatory on HTTPS ports.
2048 See http_port for a list of modes and options.
2056 Enables Native FTP proxy by specifying the socket address where Squid
2057 listens for FTP client requests. See http_port directive for various
2058 ways to specify the listening address and mode.
2060 Usage: ftp_port address [mode] [options]
2062 WARNING: This is a new, experimental, complex feature that has seen
2063 limited production exposure. Some Squid modules (e.g., caching) do not
2064 currently work with native FTP proxying, and many features have not
2065 even been tested for compatibility. Test well before deploying!
2067 Native FTP proxying differs substantially from proxying HTTP requests
2068 with ftp:// URIs because Squid works as an FTP server and receives
2069 actual FTP commands (rather than HTTP requests with FTP URLs).
2071 Native FTP commands accepted at ftp_port are internally converted or
2072 wrapped into HTTP-like messages. The same happens to Native FTP
2073 responses received from FTP origin servers. Those HTTP-like messages
2074 are shoveled through regular access control and adaptation layers
2075 between the FTP client and the FTP origin server. This allows Squid to
2076 examine, adapt, block, and log FTP exchanges. Squid reuses most HTTP
2077 mechanisms when shoveling wrapped FTP messages. For example,
2078 http_access and adaptation_access directives are used.
2082 intercept Same as http_port intercept. The FTP origin address is
2083 determined based on the intended destination of the
2084 intercepted connection.
2086 tproxy Support Linux TPROXY for spoofing outgoing
2087 connections using the client IP address.
2088 NP: disables authentication and maybe IPv6 on the port.
2090 By default (i.e., without an explicit mode option), Squid extracts the
2091 FTP origin address from the login@origin parameter of the FTP USER
2092 command. Many popular FTP clients support such native FTP proxying.
2096 name=token Specifies an internal name for the port. Defaults to
2097 the port address. Usable with myportname ACL.
2100 Enables tracking of FTP directories by injecting extra
2101 PWD commands and adjusting Request-URI (in wrapping
2102 HTTP requests) to reflect the current FTP server
2103 directory. Tracking is disabled by default.
2105 protocol=FTP Protocol to reconstruct accelerated and intercepted
2106 requests with. Defaults to FTP. No other accepted
2107 values have been tested with. An unsupported value
2108 results in a FATAL error. Accepted values are FTP,
2109 HTTP (or HTTP/1.1), and HTTPS (or HTTPS/1.1).
2111 Other http_port modes and options that are not specific to HTTP and
2112 HTTPS may also work.
2115 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
2118 LOC: Ip::Qos::TheConfig.tosToServer
2120 Allows you to select a TOS/Diffserv value for packets outgoing
2121 on the server side, based on an ACL.
2123 tcp_outgoing_tos ds-field [!]aclname ...
2125 Example where normal_service_net uses the TOS value 0x00
2126 and good_service_net uses 0x20
2128 acl normal_service_net src 10.0.0.0/24
2129 acl good_service_net src 10.0.1.0/24
2130 tcp_outgoing_tos 0x00 normal_service_net
2131 tcp_outgoing_tos 0x20 good_service_net
2133 TOS/DSCP values really only have local significance - so you should
2134 know what you're specifying. For more information, see RFC2474,
2135 RFC2475, and RFC3260.
2137 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2138 "default" to use whatever default your host has.
2139 Note that only multiples of 4 are usable as the two rightmost bits have
2140 been redefined for use by ECN (RFC 3168 section 23.1).
2141 The squid parser will enforce this by masking away the ECN bits.
2143 Processing proceeds in the order specified, and stops at first fully
2146 Only fast ACLs are supported.
2149 NAME: clientside_tos
2152 LOC: Ip::Qos::TheConfig.tosToClient
2154 Allows you to select a TOS/DSCP value for packets being transmitted
2155 on the client-side, based on an ACL.
2157 clientside_tos ds-field [!]aclname ...
2159 Example where normal_service_net uses the TOS value 0x00
2160 and good_service_net uses 0x20
2162 acl normal_service_net src 10.0.0.0/24
2163 acl good_service_net src 10.0.1.0/24
2164 clientside_tos 0x00 normal_service_net
2165 clientside_tos 0x20 good_service_net
2167 Note: This feature is incompatible with qos_flows. Any TOS values set here
2168 will be overwritten by TOS values in qos_flows.
2170 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2171 "default" to use whatever default your host has.
2172 Note that only multiples of 4 are usable as the two rightmost bits have
2173 been redefined for use by ECN (RFC 3168 section 23.1).
2174 The squid parser will enforce this by masking away the ECN bits.
2178 NAME: tcp_outgoing_mark
2180 IFDEF: SO_MARK&&USE_LIBCAP
2182 LOC: Ip::Qos::TheConfig.nfmarkToServer
2184 Allows you to apply a Netfilter mark value to outgoing packets
2185 on the server side, based on an ACL.
2187 tcp_outgoing_mark mark-value [!]aclname ...
2189 Example where normal_service_net uses the mark value 0x00
2190 and good_service_net uses 0x20
2192 acl normal_service_net src 10.0.0.0/24
2193 acl good_service_net src 10.0.1.0/24
2194 tcp_outgoing_mark 0x00 normal_service_net
2195 tcp_outgoing_mark 0x20 good_service_net
2197 Only fast ACLs are supported.
2200 NAME: clientside_mark
2202 IFDEF: SO_MARK&&USE_LIBCAP
2204 LOC: Ip::Qos::TheConfig.nfmarkToClient
2206 Allows you to apply a Netfilter mark value to packets being transmitted
2207 on the client-side, based on an ACL.
2209 clientside_mark mark-value [!]aclname ...
2211 Example where normal_service_net uses the mark value 0x00
2212 and good_service_net uses 0x20
2214 acl normal_service_net src 10.0.0.0/24
2215 acl good_service_net src 10.0.1.0/24
2216 clientside_mark 0x00 normal_service_net
2217 clientside_mark 0x20 good_service_net
2219 Note: This feature is incompatible with qos_flows. Any mark values set here
2220 will be overwritten by mark values in qos_flows.
2227 LOC: Ip::Qos::TheConfig
2229 Allows you to select a TOS/DSCP value to mark outgoing
2230 connections to the client, based on where the reply was sourced.
2231 For platforms using netfilter, allows you to set a netfilter mark
2232 value instead of, or in addition to, a TOS value.
2234 By default this functionality is disabled. To enable it with the default
2235 settings simply use "qos_flows mark" or "qos_flows tos". Default
2236 settings will result in the netfilter mark or TOS value being copied
2237 from the upstream connection to the client. Note that it is the connection
2238 CONNMARK value not the packet MARK value that is copied.
2240 It is not currently possible to copy the mark or TOS value from the
2241 client to the upstream connection request.
2243 TOS values really only have local significance - so you should
2244 know what you're specifying. For more information, see RFC2474,
2245 RFC2475, and RFC3260.
2247 The TOS/DSCP byte must be exactly that - a octet value 0 - 255.
2248 Note that only multiples of 4 are usable as the two rightmost bits have
2249 been redefined for use by ECN (RFC 3168 section 23.1).
2250 The squid parser will enforce this by masking away the ECN bits.
2252 Mark values can be any unsigned 32-bit integer value.
2254 This setting is configured by setting the following values:
2256 tos|mark Whether to set TOS or netfilter mark values
2258 local-hit=0xFF Value to mark local cache hits.
2260 sibling-hit=0xFF Value to mark hits from sibling peers.
2262 parent-hit=0xFF Value to mark hits from parent peers.
2264 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2265 over the preserve-miss feature (see below), unless
2266 mask is specified, in which case only the bits
2267 specified in the mask are written.
2269 The TOS variant of the following features are only possible on Linux
2270 and require your kernel to be patched with the TOS preserving ZPH
2271 patch, available from http://zph.bratcheda.org
2272 No patch is needed to preserve the netfilter mark, which will work
2273 with all variants of netfilter.
2275 disable-preserve-miss
2276 This option disables the preservation of the TOS or netfilter
2277 mark. By default, the existing TOS or netfilter mark value of
2278 the response coming from the remote server will be retained
2279 and masked with miss-mark.
2280 NOTE: in the case of a netfilter mark, the mark must be set on
2281 the connection (using the CONNMARK target) not on the packet
2285 Allows you to mask certain bits in the TOS or mark value
2286 received from the remote server, before copying the value to
2287 the TOS sent towards clients.
2288 Default for tos: 0xFF (TOS from server is not changed).
2289 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2291 All of these features require the --enable-zph-qos compilation flag
2292 (enabled by default). Netfilter marking also requires the
2293 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2294 libcap 2.09+ (--with-libcap).
2298 NAME: tcp_outgoing_address
2301 DEFAULT_DOC: Address selection is performed by the operating system.
2302 LOC: Config.accessList.outgoing_address
2304 Allows you to map requests to different outgoing IP addresses
2305 based on the username or source address of the user making
2308 tcp_outgoing_address ipaddr [[!]aclname] ...
2311 Forwarding clients with dedicated IPs for certain subnets.
2313 acl normal_service_net src 10.0.0.0/24
2314 acl good_service_net src 10.0.2.0/24
2316 tcp_outgoing_address 2001:db8::c001 good_service_net
2317 tcp_outgoing_address 10.1.0.2 good_service_net
2319 tcp_outgoing_address 2001:db8::beef normal_service_net
2320 tcp_outgoing_address 10.1.0.1 normal_service_net
2322 tcp_outgoing_address 2001:db8::1
2323 tcp_outgoing_address 10.1.0.3
2325 Processing proceeds in the order specified, and stops at first fully
2328 Squid will add an implicit IP version test to each line.
2329 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2330 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2333 NOTE: The use of this directive using client dependent ACLs is
2334 incompatible with the use of server side persistent connections. To
2335 ensure correct results it is best to set server_persistent_connections
2336 to off when using this directive in such configurations.
2338 NOTE: The use of this directive to set a local IP on outgoing TCP links
2339 is incompatible with using TPROXY to set client IP out outbound TCP links.
2340 When needing to contact peers use the no-tproxy cache_peer option and the
2341 client_dst_passthru directive re-enable normal forwarding such as this.
2345 NAME: host_verify_strict
2348 LOC: Config.onoff.hostStrictVerify
2350 Regardless of this option setting, when dealing with intercepted
2351 traffic, Squid always verifies that the destination IP address matches
2352 the Host header domain or IP (called 'authority form URL').
2354 This enforcement is performed to satisfy a MUST-level requirement in
2355 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2356 authority of the origin server or gateway given by the original URL".
2359 Squid always responds with an HTTP 409 (Conflict) error
2360 page and logs a security warning if there is no match.
2362 Squid verifies that the destination IP address matches
2363 the Host header for forward-proxy and reverse-proxy traffic
2364 as well. For those traffic types, Squid also enables the
2365 following checks, comparing the corresponding Host header
2366 and Request-URI components:
2368 * The host names (domain or IP) must be identical,
2369 but valueless or missing Host header disables all checks.
2370 For the two host names to match, both must be either IP
2373 * Port numbers must be identical, but if a port is missing
2374 the scheme-default port is assumed.
2377 When set to OFF (the default):
2378 Squid allows suspicious requests to continue but logs a
2379 security warning and blocks caching of the response.
2381 * Forward-proxy traffic is not checked at all.
2383 * Reverse-proxy traffic is not checked at all.
2385 * Intercepted traffic which passes verification is handled
2386 according to client_dst_passthru.
2388 * Intercepted requests which fail verification are sent
2389 to the client original destination instead of DIRECT.
2390 This overrides 'client_dst_passthru off'.
2392 For now suspicious intercepted CONNECT requests are always
2393 responded to with an HTTP 409 (Conflict) error page.
2398 As described in CVE-2009-0801 when the Host: header alone is used
2399 to determine the destination of a request it becomes trivial for
2400 malicious scripts on remote websites to bypass browser same-origin
2401 security policy and sandboxing protections.
2403 The cause of this is that such applets are allowed to perform their
2404 own HTTP stack, in which case the same-origin policy of the browser
2405 sandbox only verifies that the applet tries to contact the same IP
2406 as from where it was loaded at the IP level. The Host: header may
2407 be different from the connected IP and approved origin.
2411 NAME: client_dst_passthru
2414 LOC: Config.onoff.client_dst_passthru
2416 With NAT or TPROXY intercepted traffic Squid may pass the request
2417 directly to the original client destination IP or seek a faster
2418 source using the HTTP Host header.
2420 Using Host to locate alternative servers can provide faster
2421 connectivity with a range of failure recovery options.
2422 But can also lead to connectivity trouble when the client and
2423 server are attempting stateful interactions unaware of the proxy.
2425 This option (on by default) prevents alternative DNS entries being
2426 located to send intercepted traffic DIRECT to an origin server.
2427 The clients original destination IP and port will be used instead.
2429 Regardless of this option setting, when dealing with intercepted
2430 traffic Squid will verify the Host: header and any traffic which
2431 fails Host verification will be treated as if this option were ON.
2433 see host_verify_strict for details on the verification process.
2438 -----------------------------------------------------------------------------
2441 NAME: tls_outgoing_options
2442 IFDEF: USE_GNUTLS||USE_OPENSSL
2443 TYPE: securePeerOptions
2444 DEFAULT: min-version=1.0
2445 LOC: Security::ProxyOutgoingConfig
2447 disable Do not support https:// URLs.
2449 cert=/path/to/client/certificate
2450 A client TLS certificate to use when connecting.
2452 key=/path/to/client/private_key
2453 The private TLS key corresponding to the cert= above.
2454 If key= is not specified cert= is assumed to reference
2455 a PEM file containing both the certificate and the key.
2457 cipher=... The list of valid TLS ciphers to use.
2460 The minimum TLS protocol version to permit.
2461 To control SSLv3 use the options= parameter.
2462 Supported Values: 1.0 (default), 1.1, 1.2
2464 options=... Specify various TLS/SSL implementation options:
2466 NO_SSLv3 Disallow the use of SSLv3
2468 NO_TLSv1 Disallow the use of TLSv1.0
2470 NO_TLSv1_1 Disallow the use of TLSv1.1
2472 NO_TLSv1_2 Disallow the use of TLSv1.2
2475 Always create a new key when using
2476 temporary/ephemeral DH key exchanges
2479 Disable use of RFC5077 session tickets.
2480 Some servers may have problems
2481 understanding the TLS extension due
2482 to ambiguous specification in RFC4507.
2484 ALL Enable various bug workarounds
2485 suggested as "harmless" by OpenSSL
2486 Be warned that this reduces SSL/TLS
2487 strength to some attacks.
2489 See the OpenSSL SSL_CTX_set_options documentation for a
2492 cafile= PEM file containing CA certificates to use when verifying
2493 the peer certificate. May be repeated to load multiple files.
2495 capath= A directory containing additional CA certificates to
2496 use when verifying the peer certificate.
2497 Requires OpenSSL or LibreSSL.
2499 crlfile=... A certificate revocation list file to use when
2500 verifying the peer certificate.
2502 flags=... Specify various flags modifying the TLS implementation:
2505 Accept certificates even if they fail to
2508 Don't verify the peer certificate
2509 matches the server name
2511 no-default-ca Do not use the system default Trusted CA.
2513 domain= The peer name as advertised in its certificate.
2514 Used for verifying the correctness of the received peer
2515 certificate. If not specified the peer hostname will be
2521 -----------------------------------------------------------------------------
2524 NAME: ssl_unclean_shutdown
2528 LOC: Config.SSL.unclean_shutdown
2530 Some browsers (especially MSIE) bugs out on SSL shutdown
2537 LOC: Config.SSL.ssl_engine
2540 The OpenSSL engine to use. You will need to set this if you
2541 would like to use hardware SSL acceleration for example.
2544 NAME: sslproxy_session_ttl
2547 LOC: Config.SSL.session_ttl
2550 Sets the timeout value for SSL sessions
2553 NAME: sslproxy_session_cache_size
2556 LOC: Config.SSL.sessionCacheSize
2559 Sets the cache size to use for ssl session
2562 NAME: sslproxy_untrusted_certs
2565 LOC: Config.ssl_client.untrustedCertsPath
2568 Squid uses the intermediate certificates pre-loaded from the specified
2569 file to validate origin server certificate chains. Squid receives many
2570 incomplete chains (i.e., chains with intermediate certificates missing).
2571 The file is expected to contain zero or more PEM-encoded intermediate
2572 certificates. These certificates are not treated as trusted root
2576 NAME: sslproxy_cert_sign_hash
2579 LOC: Config.SSL.certSignHash
2582 Sets the hashing algorithm to use when signing generated certificates.
2583 Valid algorithm names depend on the OpenSSL library used. The following
2584 names are usually available: sha1, sha256, sha512, and md5. Please see
2585 your OpenSSL library manual for the available hashes. By default, Squids
2586 that support this option use sha256 hashes.
2588 Squid does not forcefully purge cached certificates that were generated
2589 with an algorithm other than the currently configured one. They remain
2590 in the cache, subject to the regular cache eviction policy, and become
2591 useful if the algorithm changes again.
2596 TYPE: sslproxy_ssl_bump
2597 LOC: Config.accessList.ssl_bump
2598 DEFAULT_DOC: Become a TCP tunnel without decrypting proxied traffic.
2601 This option is consulted when a CONNECT request is received on
2602 an http_port (or a new connection is intercepted at an
2603 https_port), provided that port was configured with an ssl-bump
2604 flag. The subsequent data on the connection is either treated as
2605 HTTPS and decrypted OR tunneled at TCP level without decryption,
2606 depending on the first matching bumping "action".
2608 ssl_bump <action> [!]acl ...
2610 The following bumping actions are currently supported:
2613 Become a TCP tunnel without decrypting proxied traffic.
2614 This is the default action.
2617 Establish a secure connection with the server and, using a
2618 mimicked server certificate, with the client.
2621 Receive client (step SslBump1) or server (step SslBump2)
2622 certificate while preserving the possibility of splicing the
2623 connection. Peeking at the server certificate (during step 2)
2624 usually precludes bumping of the connection at step 3.
2627 Receive client (step SslBump1) or server (step SslBump2)
2628 certificate while preserving the possibility of bumping the
2629 connection. Staring at the server certificate (during step 2)
2630 usually precludes splicing of the connection at step 3.
2633 Close client and server connections.
2635 Backward compatibility actions available at step SslBump1:
2638 Bump the connection. Establish a secure connection with the
2639 client first, then connect to the server. This old mode does
2640 not allow Squid to mimic server SSL certificate and does not
2641 work with intercepted SSL connections.
2644 Bump the connection. Establish a secure connection with the
2645 server first, then establish a secure connection with the
2646 client, using a mimicked server certificate. Works with both
2647 CONNECT requests and intercepted SSL connections, but does
2648 not allow to make decisions based on SSL handshake info.
2651 Decide whether to bump or splice the connection based on
2652 client-to-squid and server-to-squid SSL hello messages.
2656 Same as the "splice" action.
2658 All ssl_bump rules are evaluated at each of the supported bumping
2659 steps. Rules with actions that are impossible at the current step are
2660 ignored. The first matching ssl_bump action wins and is applied at the
2661 end of the current step. If no rules match, the splice action is used.
2662 See the at_step ACL for a list of the supported SslBump steps.
2664 This clause supports both fast and slow acl types.
2665 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2667 See also: http_port ssl-bump, https_port ssl-bump, and acl at_step.
2670 # Example: Bump all requests except those originating from
2671 # localhost or those going to example.com.
2673 acl broken_sites dstdomain .example.com
2674 ssl_bump splice localhost
2675 ssl_bump splice broken_sites
2679 NAME: sslproxy_cert_error
2682 DEFAULT_DOC: Server certificate errors terminate the transaction.
2683 LOC: Config.ssl_client.cert_error
2686 Use this ACL to bypass server certificate validation errors.
2688 For example, the following lines will bypass all validation errors
2689 when talking to servers for example.com. All other
2690 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2692 acl BrokenButTrustedServers dstdomain example.com
2693 sslproxy_cert_error allow BrokenButTrustedServers
2694 sslproxy_cert_error deny all
2696 This clause only supports fast acl types.
2697 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2698 Using slow acl types may result in server crashes
2700 Without this option, all server certificate validation errors
2701 terminate the transaction to protect Squid and the client.
2703 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2704 but should not happen unless your OpenSSL library is buggy.
2707 Bypassing validation errors is dangerous because an
2708 error usually implies that the server cannot be trusted
2709 and the connection may be insecure.
2711 See also: sslproxy_flags and DONT_VERIFY_PEER.
2714 NAME: sslproxy_cert_sign
2717 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2718 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2719 POSTSCRIPTUM: signTrusted all
2720 TYPE: sslproxy_cert_sign
2721 LOC: Config.ssl_client.cert_sign
2724 sslproxy_cert_sign <signing algorithm> acl ...
2726 The following certificate signing algorithms are supported:
2729 Sign using the configured CA certificate which is usually
2730 placed in and trusted by end-user browsers. This is the
2731 default for trusted origin server certificates.
2734 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2735 This is the default for untrusted origin server certificates
2736 that are not self-signed (see ssl::certUntrusted).
2739 Sign using a self-signed certificate with the right CN to
2740 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2741 browser. This is the default for self-signed origin server
2742 certificates (see ssl::certSelfSigned).
2744 This clause only supports fast acl types.
2746 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2747 signing algorithm to generate the certificate and ignores all
2748 subsequent sslproxy_cert_sign options (the first match wins). If no
2749 acl(s) match, the default signing algorithm is determined by errors
2750 detected when obtaining and validating the origin server certificate.
2752 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2753 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2754 CONNECT request that carries a domain name. In all other cases (CONNECT
2755 to an IP address or an intercepted SSL connection), Squid cannot detect
2756 the domain mismatch at certificate generation time when
2757 bump-server-first is used.
2760 NAME: sslproxy_cert_adapt
2763 TYPE: sslproxy_cert_adapt
2764 LOC: Config.ssl_client.cert_adapt
2767 sslproxy_cert_adapt <adaptation algorithm> acl ...
2769 The following certificate adaptation algorithms are supported:
2772 Sets the "Not After" property to the "Not After" property of
2773 the CA certificate used to sign generated certificates.
2776 Sets the "Not Before" property to the "Not Before" property of
2777 the CA certificate used to sign generated certificates.
2779 setCommonName or setCommonName{CN}
2780 Sets Subject.CN property to the host name specified as a
2781 CN parameter or, if no explicit CN parameter was specified,
2782 extracted from the CONNECT request. It is a misconfiguration
2783 to use setCommonName without an explicit parameter for
2784 intercepted or tproxied SSL connections.
2786 This clause only supports fast acl types.
2788 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2789 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2790 corresponding adaptation algorithm to generate the certificate and
2791 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2792 group (i.e., the first match wins within each algorithm group). If no
2793 acl(s) match, the default mimicking action takes place.
2795 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2796 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2797 CONNECT request that carries a domain name. In all other cases (CONNECT
2798 to an IP address or an intercepted SSL connection), Squid cannot detect
2799 the domain mismatch at certificate generation time when
2800 bump-server-first is used.
2803 NAME: sslpassword_program
2806 LOC: Config.Program.ssl_password
2809 Specify a program used for entering SSL key passphrases
2810 when using encrypted SSL certificate keys. If not specified
2811 keys must either be unencrypted, or Squid started with the -N
2812 option to allow it to query interactively for the passphrase.
2814 The key file name is given as argument to the program allowing
2815 selection of the right password if you have multiple encrypted
2820 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2821 -----------------------------------------------------------------------------
2824 NAME: sslcrtd_program
2827 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2828 LOC: Ssl::TheConfig.ssl_crtd
2830 Specify the location and options of the executable for ssl_crtd process.
2831 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2832 For more information use:
2833 @DEFAULT_SSL_CRTD@ -h
2836 NAME: sslcrtd_children
2837 TYPE: HelperChildConfig
2839 DEFAULT: 32 startup=5 idle=1
2840 LOC: Ssl::TheConfig.ssl_crtdChildren
2842 The maximum number of processes spawn to service ssl server.
2843 The maximum this may be safely set to is 32.
2845 The startup= and idle= options allow some measure of skew in your
2850 Sets the minimum number of processes to spawn when Squid
2851 starts or reconfigures. When set to zero the first request will
2852 cause spawning of the first child process to handle it.
2854 Starting too few children temporary slows Squid under load while it
2855 tries to spawn enough additional processes to cope with traffic.
2859 Sets a minimum of how many processes Squid is to try and keep available
2860 at all times. When traffic begins to rise above what the existing
2861 processes can handle this many more will be spawned up to the maximum
2862 configured. A minimum setting of 1 is required.
2866 Sets the maximum number of queued requests.
2867 If the queued requests exceed queue size for more than 3 minutes
2868 squid aborts its operation.
2869 The default value is set to 2*numberofchildren.
2871 You must have at least one ssl_crtd process.
2874 NAME: sslcrtvalidator_program
2878 LOC: Ssl::TheConfig.ssl_crt_validator
2880 Specify the location and options of the executable for ssl_crt_validator
2883 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
2886 ttl=n TTL in seconds for cached results. The default is 60 secs
2887 cache=n limit the result cache size. The default value is 2048
2890 NAME: sslcrtvalidator_children
2891 TYPE: HelperChildConfig
2893 DEFAULT: 32 startup=5 idle=1 concurrency=1
2894 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2896 The maximum number of processes spawn to service SSL server.
2897 The maximum this may be safely set to is 32.
2899 The startup= and idle= options allow some measure of skew in your
2904 Sets the minimum number of processes to spawn when Squid
2905 starts or reconfigures. When set to zero the first request will
2906 cause spawning of the first child process to handle it.
2908 Starting too few children temporary slows Squid under load while it
2909 tries to spawn enough additional processes to cope with traffic.
2913 Sets a minimum of how many processes Squid is to try and keep available
2914 at all times. When traffic begins to rise above what the existing
2915 processes can handle this many more will be spawned up to the maximum
2916 configured. A minimum setting of 1 is required.
2920 The number of requests each certificate validator helper can handle in
2921 parallel. A value of 0 indicates the certficate validator does not
2922 support concurrency. Defaults to 1.
2924 When this directive is set to a value >= 1 then the protocol
2925 used to communicate with the helper is modified to include
2926 a request ID in front of the request/response. The request
2927 ID from the request must be echoed back with the response
2932 Sets the maximum number of queued requests.
2933 If the queued requests exceed queue size for more than 3 minutes
2934 squid aborts its operation.
2935 The default value is set to 2*numberofchildren.
2937 You must have at least one ssl_crt_validator process.
2941 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2942 -----------------------------------------------------------------------------
2950 To specify other caches in a hierarchy, use the format:
2952 cache_peer hostname type http-port icp-port [options]
2957 # hostname type port port options
2958 # -------------------- -------- ----- ----- -----------
2959 cache_peer parent.foo.net parent 3128 3130 default
2960 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2961 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2962 cache_peer example.com parent 80 0 default
2963 cache_peer cdn.example.com sibling 3128 0
2965 type: either 'parent', 'sibling', or 'multicast'.
2967 proxy-port: The port number where the peer accept HTTP requests.
2968 For other Squid proxies this is usually 3128
2969 For web servers this is usually 80
2971 icp-port: Used for querying neighbor caches about objects.
2972 Set to 0 if the peer does not support ICP or HTCP.
2973 See ICP and HTCP options below for additional details.
2976 ==== ICP OPTIONS ====
2978 You MUST also set icp_port and icp_access explicitly when using these options.
2979 The defaults will prevent peer traffic using ICP.
2982 no-query Disable ICP queries to this neighbor.
2985 Indicates the named peer is a member of a multicast group.
2986 ICP queries will not be sent directly to the peer, but ICP
2987 replies will be accepted from it.
2989 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2990 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2993 To only send ICP queries to this neighbor infrequently.
2994 This is used to keep the neighbor round trip time updated
2995 and is usually used in conjunction with weighted-round-robin.
2998 ==== HTCP OPTIONS ====
3000 You MUST also set htcp_port and htcp_access explicitly when using these options.
3001 The defaults will prevent peer traffic using HTCP.
3004 htcp Send HTCP, instead of ICP, queries to the neighbor.
3005 You probably also want to set the "icp-port" to 4827
3006 instead of 3130. This directive accepts a comma separated
3007 list of options described below.
3009 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
3011 htcp=no-clr Send HTCP to the neighbor but without
3012 sending any CLR requests. This cannot be used with
3015 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
3016 This cannot be used with no-clr.
3019 Send HTCP to the neighbor including CLRs but only when
3020 they do not result from PURGE requests.
3023 Forward any HTCP CLR requests this proxy receives to the peer.
3026 ==== PEER SELECTION METHODS ====
3028 The default peer selection method is ICP, with the first responding peer
3029 being used as source. These options can be used for better load balancing.
3032 default This is a parent cache which can be used as a "last-resort"
3033 if a peer cannot be located by any of the peer-selection methods.
3034 If specified more than once, only the first is used.
3036 round-robin Load-Balance parents which should be used in a round-robin
3037 fashion in the absence of any ICP queries.
3038 weight=N can be used to add bias.
3040 weighted-round-robin
3041 Load-Balance parents which should be used in a round-robin
3042 fashion with the frequency of each parent being based on the
3043 round trip time. Closer parents are used more often.
3044 Usually used for background-ping parents.
3045 weight=N can be used to add bias.
3047 carp Load-Balance parents which should be used as a CARP array.
3048 The requests will be distributed among the parents based on the
3049 CARP load balancing hash function based on their weight.
3051 userhash Load-balance parents based on the client proxy_auth or ident username.
3053 sourcehash Load-balance parents based on the client source IP.
3056 To be used only for cache peers of type "multicast".
3057 ALL members of this multicast group have "sibling"
3058 relationship with it, not "parent". This is to a multicast
3059 group when the requested object would be fetched only from
3060 a "parent" cache, anyway. It's useful, e.g., when
3061 configuring a pool of redundant Squid proxies, being
3062 members of the same multicast group.
3065 ==== PEER SELECTION OPTIONS ====
3067 weight=N use to affect the selection of a peer during any weighted
3068 peer-selection mechanisms.
3069 The weight must be an integer; default is 1,
3070 larger weights are favored more.
3071 This option does not affect parent selection if a peering
3072 protocol is not in use.
3074 basetime=N Specify a base amount to be subtracted from round trip
3076 It is subtracted before division by weight in calculating
3077 which parent to fectch from. If the rtt is less than the
3078 base time the rtt is set to a minimal value.
3080 ttl=N Specify a TTL to use when sending multicast ICP queries
3082 Only useful when sending to a multicast group.
3083 Because we don't accept ICP replies from random
3084 hosts, you must configure other group members as
3085 peers with the 'multicast-responder' option.
3087 no-delay To prevent access to this neighbor from influencing the
3090 digest-url=URL Tell Squid to fetch the cache digest (if digests are
3091 enabled) for this host from the specified URL rather
3092 than the Squid default location.
3095 ==== CARP OPTIONS ====
3097 carp-key=key-specification
3098 use a different key than the full URL to hash against the peer.
3099 the key-specification is a comma-separated list of the keywords
3100 scheme, host, port, path, params
3101 Order is not important.
3103 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
3105 originserver Causes this parent to be contacted as an origin server.
3106 Meant to be used in accelerator setups when the peer
3110 Set the Host header of requests forwarded to this peer.
3111 Useful in accelerator setups where the server (peer)
3112 expects a certain domain name but clients may request
3113 others. ie example.com or www.example.com
3115 no-digest Disable request of cache digests.
3118 Disables requesting ICMP RTT database (NetDB).
3121 ==== AUTHENTICATION OPTIONS ====
3124 If this is a personal/workgroup proxy and your parent
3125 requires proxy authentication.
3127 Note: The string can include URL escapes (i.e. %20 for
3128 spaces). This also means % must be written as %%.
3131 Send login details received from client to this peer.
3132 Both Proxy- and WWW-Authorization headers are passed
3133 without alteration to the peer.
3134 Authentication is not required by Squid for this to work.
3136 Note: This will pass any form of authentication but
3137 only Basic auth will work through a proxy unless the
3138 connection-auth options are also used.
3140 login=PASS Send login details received from client to this peer.
3141 Authentication is not required by this option.
3143 If there are no client-provided authentication headers
3144 to pass on, but username and password are available
3145 from an external ACL user= and password= result tags
3146 they may be sent instead.
3148 Note: To combine this with proxy_auth both proxies must
3149 share the same user database as HTTP only allows for
3150 a single login (one for proxy, one for origin server).
3151 Also be warned this will expose your users proxy
3152 password to the peer. USE WITH CAUTION
3155 Send the username to the upstream cache, but with a
3156 fixed password. This is meant to be used when the peer
3157 is in another administrative domain, but it is still
3158 needed to identify each user.
3159 The star can optionally be followed by some extra
3160 information which is added to the username. This can
3161 be used to identify this proxy to the peer, similar to
3162 the login=username:password option above.
3165 If this is a personal/workgroup proxy and your parent
3166 requires a secure proxy authentication.
3167 The first principal from the default keytab or defined by
3168 the environment variable KRB5_KTNAME will be used.
3170 WARNING: The connection may transmit requests from multiple
3171 clients. Negotiate often assumes end-to-end authentication
3172 and a single-client. Which is not strictly true here.
3174 login=NEGOTIATE:principal_name
3175 If this is a personal/workgroup proxy and your parent
3176 requires a secure proxy authentication.
3177 The principal principal_name from the default keytab or
3178 defined by the environment variable KRB5_KTNAME will be
3181 WARNING: The connection may transmit requests from multiple
3182 clients. Negotiate often assumes end-to-end authentication
3183 and a single-client. Which is not strictly true here.
3185 connection-auth=on|off
3186 Tell Squid that this peer does or not support Microsoft
3187 connection oriented authentication, and any such
3188 challenges received from there should be ignored.
3189 Default is auto to automatically determine the status
3193 ==== SSL / HTTPS / TLS OPTIONS ====
3195 ssl Encrypt connections to this peer with SSL/TLS.
3197 sslcert=/path/to/ssl/certificate
3198 A client SSL certificate to use when connecting to
3201 sslkey=/path/to/ssl/key
3202 The private SSL key corresponding to sslcert above.
3203 If 'sslkey' is not specified 'sslcert' is assumed to
3204 reference a combined file containing both the
3205 certificate and the key.
3207 sslcipher=... The list of valid SSL ciphers to use when connecting
3211 The minimum TLS protocol version to permit. To control
3212 SSLv3 use the ssloptions= parameter.
3213 Supported Values: 1.0 (default), 1.1, 1.2
3215 ssloptions=... Specify various SSL implementation options:
3217 NO_SSLv3 Disallow the use of SSLv3
3219 NO_TLSv1 Disallow the use of TLSv1.0
3221 NO_TLSv1_1 Disallow the use of TLSv1.1
3223 NO_TLSv1_2 Disallow the use of TLSv1.2
3226 Always create a new key when using
3227 temporary/ephemeral DH key exchanges
3230 Disable use of RFC5077 session tickets.
3231 Some servers may have problems
3232 understanding the TLS extension due
3233 to ambiguous specification in RFC4507.
3235 ALL Enable various bug workarounds
3236 suggested as "harmless" by OpenSSL
3237 Be warned that this reduces SSL/TLS
3238 strength to some attacks.
3240 See the OpenSSL SSL_CTX_set_options documentation for a
3243 tls-cafile= PEM file containing CA certificates to use when verifying
3244 the peer certificate. May be repeated to load multiple files.
3246 sslcapath=... A directory containing additional CA certificates to
3247 use when verifying the peer certificate.
3248 Requires OpenSSL or LibreSSL.
3250 sslcrlfile=... A certificate revocation list file to use when
3251 verifying the peer certificate.
3253 sslflags=... Specify various flags modifying the SSL implementation:
3256 Accept certificates even if they fail to
3260 Don't verify the peer certificate
3261 matches the server name
3263 ssldomain= The peer name as advertised in it's certificate.
3264 Used for verifying the correctness of the received peer
3265 certificate. If not specified the peer hostname will be
3269 Enable the "Front-End-Https: On" header needed when
3270 using Squid as a SSL frontend in front of Microsoft OWA.
3271 See MS KB document Q307347 for details on this header.
3272 If set to auto the header will only be added if the
3273 request is forwarded as a https:// URL.
3276 Do not use the system default Trusted CA.
3278 ==== GENERAL OPTIONS ====
3281 A peer-specific connect timeout.
3282 Also see the peer_connect_timeout directive.
3284 connect-fail-limit=N
3285 How many times connecting to a peer must fail before
3286 it is marked as down. Standby connection failures
3287 count towards this limit. Default is 10.
3289 allow-miss Disable Squid's use of only-if-cached when forwarding
3290 requests to siblings. This is primarily useful when
3291 icp_hit_stale is used by the sibling. To extensive use
3292 of this option may result in forwarding loops, and you
3293 should avoid having two-way peerings with this option.
3294 For example to deny peer usage on requests from peer
3295 by denying cache_peer_access if the source is a peer.
3297 max-conn=N Limit the number of concurrent connections the Squid
3298 may open to this peer, including already opened idle
3299 and standby connections. There is no peer-specific
3300 connection limit by default.
3302 A peer exceeding the limit is not used for new
3303 requests unless a standby connection is available.
3305 max-conn currently works poorly with idle persistent
3306 connections: When a peer reaches its max-conn limit,
3307 and there are idle persistent connections to the peer,
3308 the peer may not be selected because the limiting code
3309 does not know whether Squid can reuse those idle
3312 standby=N Maintain a pool of N "hot standby" connections to an
3313 UP peer, available for requests when no idle
3314 persistent connection is available (or safe) to use.
3315 By default and with zero N, no such pool is maintained.
3316 N must not exceed the max-conn limit (if any).
3318 At start or after reconfiguration, Squid opens new TCP
3319 standby connections until there are N connections
3320 available and then replenishes the standby pool as
3321 opened connections are used up for requests. A used
3322 connection never goes back to the standby pool, but
3323 may go to the regular idle persistent connection pool
3324 shared by all peers and origin servers.
3326 Squid never opens multiple new standby connections
3327 concurrently. This one-at-a-time approach minimizes
3328 flooding-like effect on peers. Furthermore, just a few
3329 standby connections should be sufficient in most cases
3330 to supply most new requests with a ready-to-use
3333 Standby connections obey server_idle_pconn_timeout.
3334 For the feature to work as intended, the peer must be
3335 configured to accept and keep them open longer than
3336 the idle timeout at the connecting Squid, to minimize
3337 race conditions typical to idle used persistent
3338 connections. Default request_timeout and
3339 server_idle_pconn_timeout values ensure such a
3342 name=xxx Unique name for the peer.
3343 Required if you have multiple peers on the same host
3344 but different ports.
3345 This name can be used in cache_peer_access and similar
3346 directives to dentify the peer.
3347 Can be used by outgoing access controls through the
3350 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3351 requests to this peer. Use normal address selection instead.
3352 This overrides the spoof_client_ip ACL.
3354 proxy-only objects fetched from the peer will not be stored locally.
3358 NAME: cache_peer_access
3363 Use to limit the requests for which a neighbor proxy will be
3364 queried. Peers with no restrictions are queried for all requests.
3367 cache_peer_access cache-host allow|deny [!]aclname ...
3369 The syntax is identical to 'http_access' and the other lists of
3370 ACL elements. See the comments for 'http_access', or the
3371 Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
3374 NAME: neighbor_type_domain
3375 TYPE: hostdomaintype
3377 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3380 Modify the cache_peer neighbor type when passing requests
3381 about specific domains to the peer.
3384 neighbor_type_domain neighbor parent|sibling domain domain ...
3387 cache_peer foo.example.com parent 3128 3130
3388 neighbor_type_domain foo.example.com sibling .au .de
3390 The above configuration treats all requests to foo.example.com as a
3391 parent proxy unless the request is for a .au or .de ccTLD domain name.
3394 NAME: dead_peer_timeout
3398 LOC: Config.Timeout.deadPeer
3400 This controls how long Squid waits to declare a peer cache
3401 as "dead." If there are no ICP replies received in this
3402 amount of time, Squid will declare the peer dead and not
3403 expect to receive any further ICP replies. However, it
3404 continues to send ICP queries, and will mark the peer as
3405 alive upon receipt of the first subsequent ICP reply.
3407 This timeout also affects when Squid expects to receive ICP
3408 replies from peers. If more than 'dead_peer' seconds have
3409 passed since the last ICP reply was received, Squid will not
3410 expect to receive an ICP reply on the next query. Thus, if
3411 your time between requests is greater than this timeout, you
3412 will see a lot of requests sent DIRECT to origin servers
3413 instead of to your parents.
3416 NAME: forward_max_tries
3419 LOC: Config.forward_max_tries
3421 Controls how many different forward paths Squid will try
3422 before giving up. See also forward_timeout.
3424 NOTE: connect_retries (default: none) can make each of these
3425 possible forwarding paths be tried multiple times.
3429 MEMORY CACHE OPTIONS
3430 -----------------------------------------------------------------------------
3437 LOC: Config.memMaxSize
3439 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3440 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3441 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3442 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3444 'cache_mem' specifies the ideal amount of memory to be used
3446 * In-Transit objects
3448 * Negative-Cached objects
3450 Data for these objects are stored in 4 KB blocks. This
3451 parameter specifies the ideal upper limit on the total size of
3452 4 KB blocks allocated. In-Transit objects take the highest
3455 In-transit objects have priority over the others. When
3456 additional space is needed for incoming data, negative-cached
3457 and hot objects will be released. In other words, the
3458 negative-cached and hot objects will fill up any unused space
3459 not needed for in-transit objects.
3461 If circumstances require, this limit will be exceeded.
3462 Specifically, if your incoming request rate requires more than
3463 'cache_mem' of memory to hold in-transit objects, Squid will
3464 exceed this limit to satisfy the new requests. When the load
3465 decreases, blocks will be freed until the high-water mark is
3466 reached. Thereafter, blocks will be used to store hot
3469 If shared memory caching is enabled, Squid does not use the shared
3470 cache space for in-transit objects, but they still consume as much
3471 local memory as they need. For more details about the shared memory
3472 cache, see memory_cache_shared.
3475 NAME: maximum_object_size_in_memory
3479 LOC: Config.Store.maxInMemObjSize
3481 Objects greater than this size will not be attempted to kept in
3482 the memory cache. This should be set high enough to keep objects
3483 accessed frequently in memory to improve performance whilst low
3484 enough to keep larger objects from hoarding cache_mem.
3487 NAME: memory_cache_shared
3490 LOC: Config.memShared
3492 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3494 Controls whether the memory cache is shared among SMP workers.
3496 The shared memory cache is meant to occupy cache_mem bytes and replace
3497 the non-shared memory cache, although some entities may still be
3498 cached locally by workers for now (e.g., internal and in-transit
3499 objects may be served from a local memory cache even if shared memory
3500 caching is enabled).
3502 By default, the memory cache is shared if and only if all of the
3503 following conditions are satisfied: Squid runs in SMP mode with
3504 multiple workers, cache_mem is positive, and Squid environment
3505 supports required IPC primitives (e.g., POSIX shared memory segments
3506 and GCC-style atomic operations).
3508 To avoid blocking locks, shared memory uses opportunistic algorithms
3509 that do not guarantee that every cachable entity that could have been
3510 shared among SMP workers will actually be shared.
3512 Currently, entities exceeding 32KB in size cannot be shared.
3515 NAME: memory_cache_mode
3519 DEFAULT_DOC: Keep the most recently fetched objects in memory
3521 Controls which objects to keep in the memory cache (cache_mem)
3523 always Keep most recently fetched objects in memory (default)
3525 disk Only disk cache hits are kept in memory, which means
3526 an object must first be cached on disk and then hit
3527 a second time before cached in memory.
3529 network Only objects fetched from network is kept in memory
3532 NAME: memory_replacement_policy
3534 LOC: Config.memPolicy
3537 The memory replacement policy parameter determines which
3538 objects are purged from memory when memory space is needed.
3540 See cache_replacement_policy for details on algorithms.
3545 -----------------------------------------------------------------------------
3548 NAME: cache_replacement_policy
3550 LOC: Config.replPolicy
3553 The cache replacement policy parameter determines which
3554 objects are evicted (replaced) when disk space is needed.
3556 lru : Squid's original list based LRU policy
3557 heap GDSF : Greedy-Dual Size Frequency
3558 heap LFUDA: Least Frequently Used with Dynamic Aging
3559 heap LRU : LRU policy implemented using a heap
3561 Applies to any cache_dir lines listed below this directive.
3563 The LRU policies keeps recently referenced objects.
3565 The heap GDSF policy optimizes object hit rate by keeping smaller
3566 popular objects in cache so it has a better chance of getting a
3567 hit. It achieves a lower byte hit rate than LFUDA though since
3568 it evicts larger (possibly popular) objects.
3570 The heap LFUDA policy keeps popular objects in cache regardless of
3571 their size and thus optimizes byte hit rate at the expense of
3572 hit rate since one large, popular object will prevent many
3573 smaller, slightly less popular objects from being cached.
3575 Both policies utilize a dynamic aging mechanism that prevents
3576 cache pollution that can otherwise occur with frequency-based
3577 replacement policies.
3579 NOTE: if using the LFUDA replacement policy you should increase
3580 the value of maximum_object_size above its default of 4 MB to
3581 to maximize the potential byte hit rate improvement of LFUDA.
3583 For more information about the GDSF and LFUDA cache replacement
3584 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3585 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3588 NAME: minimum_object_size
3592 DEFAULT_DOC: no limit
3593 LOC: Config.Store.minObjectSize
3595 Objects smaller than this size will NOT be saved on disk. The
3596 value is specified in bytes, and the default is 0 KB, which
3597 means all responses can be stored.
3600 NAME: maximum_object_size
3604 LOC: Config.Store.maxObjectSize
3606 Set the default value for max-size parameter on any cache_dir.
3607 The value is specified in bytes, and the default is 4 MB.
3609 If you wish to get a high BYTES hit ratio, you should probably
3610 increase this (one 32 MB object hit counts for 3200 10KB
3613 If you wish to increase hit ratio more than you want to
3614 save bandwidth you should leave this low.
3616 NOTE: if using the LFUDA replacement policy you should increase
3617 this value to maximize the byte hit rate improvement of LFUDA!
3618 See cache_replacement_policy for a discussion of this policy.
3624 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3625 LOC: Config.cacheSwap
3628 cache_dir Type Directory-Name Fs-specific-data [options]
3630 You can specify multiple cache_dir lines to spread the
3631 cache among different disk partitions.
3633 Type specifies the kind of storage system to use. Only "ufs"
3634 is built by default. To enable any of the other storage systems
3635 see the --enable-storeio configure option.
3637 'Directory' is a top-level directory where cache swap
3638 files will be stored. If you want to use an entire disk
3639 for caching, this can be the mount-point directory.
3640 The directory must exist and be writable by the Squid
3641 process. Squid will NOT create this directory for you.
3643 In SMP configurations, cache_dir must not precede the workers option
3644 and should use configuration macros or conditionals to give each
3645 worker interested in disk caching a dedicated cache directory.
3648 ==== The ufs store type ====
3650 "ufs" is the old well-known Squid storage format that has always
3654 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3656 'Mbytes' is the amount of disk space (MB) to use under this
3657 directory. The default is 100 MB. Change this to suit your
3658 configuration. Do NOT put the size of your disk drive here.
3659 Instead, if you want Squid to use the entire disk drive,
3660 subtract 20% and use that value.
3662 'L1' is the number of first-level subdirectories which
3663 will be created under the 'Directory'. The default is 16.
3665 'L2' is the number of second-level subdirectories which
3666 will be created under each first-level directory. The default
3670 ==== The aufs store type ====
3672 "aufs" uses the same storage format as "ufs", utilizing
3673 POSIX-threads to avoid blocking the main Squid process on
3674 disk-I/O. This was formerly known in Squid as async-io.
3677 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3679 see argument descriptions under ufs above
3682 ==== The diskd store type ====
3684 "diskd" uses the same storage format as "ufs", utilizing a
3685 separate process to avoid blocking the main Squid process on
3689 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3691 see argument descriptions under ufs above
3693 Q1 specifies the number of unacknowledged I/O requests when Squid
3694 stops opening new files. If this many messages are in the queues,
3695 Squid won't open new files. Default is 64
3697 Q2 specifies the number of unacknowledged messages when Squid
3698 starts blocking. If this many messages are in the queues,
3699 Squid blocks until it receives some replies. Default is 72
3701 When Q1 < Q2 (the default), the cache directory is optimized
3702 for lower response time at the expense of a decrease in hit
3703 ratio. If Q1 > Q2, the cache directory is optimized for
3704 higher hit ratio at the expense of an increase in response
3708 ==== The rock store type ====
3711 cache_dir rock Directory-Name Mbytes [options]
3713 The Rock Store type is a database-style storage. All cached
3714 entries are stored in a "database" file, using fixed-size slots.
3715 A single entry occupies one or more slots.
3717 If possible, Squid using Rock Store creates a dedicated kid
3718 process called "disker" to avoid blocking Squid worker(s) on disk
3719 I/O. One disker kid is created for each rock cache_dir. Diskers
3720 are created only when Squid, running in daemon mode, has support
3721 for the IpcIo disk I/O module.
3723 swap-timeout=msec: Squid will not start writing a miss to or
3724 reading a hit from disk if it estimates that the swap operation
3725 will take more than the specified number of milliseconds. By
3726 default and when set to zero, disables the disk I/O time limit
3727 enforcement. Ignored when using blocking I/O module because
3728 blocking synchronous I/O does not allow Squid to estimate the
3729 expected swap wait time.
3731 max-swap-rate=swaps/sec: Artificially limits disk access using
3732 the specified I/O rate limit. Swap out requests that
3733 would cause the average I/O rate to exceed the limit are
3734 delayed. Individual swap in requests (i.e., hits or reads) are
3735 not delayed, but they do contribute to measured swap rate and
3736 since they are placed in the same FIFO queue as swap out
3737 requests, they may wait longer if max-swap-rate is smaller.
3738 This is necessary on file systems that buffer "too
3739 many" writes and then start blocking Squid and other processes
3740 while committing those writes to disk. Usually used together
3741 with swap-timeout to avoid excessive delays and queue overflows
3742 when disk demand exceeds available disk "bandwidth". By default
3743 and when set to zero, disables the disk I/O rate limit
3744 enforcement. Currently supported by IpcIo module only.
3746 slot-size=bytes: The size of a database "record" used for
3747 storing cached responses. A cached response occupies at least
3748 one slot and all database I/O is done using individual slots so
3749 increasing this parameter leads to more disk space waste while
3750 decreasing it leads to more disk I/O overheads. Should be a
3751 multiple of your operating system I/O page size. Defaults to
3752 16KBytes. A housekeeping header is stored with each slot and
3753 smaller slot-sizes will be rejected. The header is smaller than
3757 ==== COMMON OPTIONS ====
3759 no-store no new objects should be stored to this cache_dir.
3761 min-size=n the minimum object size in bytes this cache_dir
3762 will accept. It's used to restrict a cache_dir
3763 to only store large objects (e.g. AUFS) while
3764 other stores are optimized for smaller objects
3768 max-size=n the maximum object size in bytes this cache_dir
3770 The value in maximum_object_size directive sets
3771 the default unless more specific details are
3772 available (ie a small store capacity).
3774 Note: To make optimal use of the max-size limits you should order
3775 the cache_dir lines with the smallest max-size value first.
3779 # Uncomment and adjust the following to add a disk cache directory.
3780 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3784 NAME: store_dir_select_algorithm
3786 LOC: Config.store_dir_select_algorithm
3789 How Squid selects which cache_dir to use when the response
3790 object will fit into more than one.
3792 Regardless of which algorithm is used the cache_dir min-size
3793 and max-size parameters are obeyed. As such they can affect
3794 the selection algorithm by limiting the set of considered
3801 This algorithm is suited to caches with similar cache_dir
3802 sizes and disk speeds.
3804 The disk with the least I/O pending is selected.
3805 When there are multiple disks with the same I/O load ranking
3806 the cache_dir with most available capacity is selected.
3808 When a mix of cache_dir sizes are configured the faster disks
3809 have a naturally lower I/O loading and larger disks have more
3810 capacity. So space used to store objects and data throughput
3811 may be very unbalanced towards larger disks.
3816 This algorithm is suited to caches with unequal cache_dir
3819 Each cache_dir is selected in a rotation. The next suitable
3822 Available cache_dir capacity is only considered in relation
3823 to whether the object will fit and meets the min-size and
3824 max-size parameters.
3826 Disk I/O loading is only considered to prevent overload on slow
3827 disks. This algorithm does not spread objects by size, so any
3828 I/O loading per-disk may appear very unbalanced and volatile.
3830 If several cache_dirs use similar min-size, max-size, or other
3831 limits to to reject certain responses, then do not group such
3832 cache_dir lines together, to avoid round-robin selection bias
3833 towards the first cache_dir after the group. Instead, interleave
3834 cache_dir lines from different groups. For example:
3836 store_dir_select_algorithm round-robin
3837 cache_dir rock /hdd1 ... min-size=100000
3838 cache_dir rock /ssd1 ... max-size=99999
3839 cache_dir rock /hdd2 ... min-size=100000
3840 cache_dir rock /ssd2 ... max-size=99999
3841 cache_dir rock /hdd3 ... min-size=100000
3842 cache_dir rock /ssd3 ... max-size=99999
3845 NAME: max_open_disk_fds
3847 LOC: Config.max_open_disk_fds
3849 DEFAULT_DOC: no limit
3851 To avoid having disk as the I/O bottleneck Squid can optionally
3852 bypass the on-disk cache if more than this amount of disk file
3853 descriptors are open.
3855 A value of 0 indicates no limit.
3858 NAME: cache_swap_low
3859 COMMENT: (percent, 0-100)
3862 LOC: Config.Swap.lowWaterMark
3864 The low-water mark for AUFS/UFS/diskd cache object eviction by
3865 the cache_replacement_policy algorithm.
3867 Removal begins when the swap (disk) usage of a cache_dir is
3868 above this low-water mark and attempts to maintain utilization
3869 near the low-water mark.
3871 As swap utilization increases towards the high-water mark set
3872 by cache_swap_high object eviction becomes more agressive.
3874 The value difference in percentages between low- and high-water
3875 marks represent an eviction rate of 300 objects per second and
3876 the rate continues to scale in agressiveness by multiples of
3877 this above the high-water mark.
3879 Defaults are 90% and 95%. If you have a large cache, 5% could be
3880 hundreds of MB. If this is the case you may wish to set these
3881 numbers closer together.
3883 See also cache_swap_high and cache_replacement_policy
3886 NAME: cache_swap_high
3887 COMMENT: (percent, 0-100)
3890 LOC: Config.Swap.highWaterMark
3892 The high-water mark for AUFS/UFS/diskd cache object eviction by
3893 the cache_replacement_policy algorithm.
3895 Removal begins when the swap (disk) usage of a cache_dir is
3896 above the low-water mark set by cache_swap_low and attempts to
3897 maintain utilization near the low-water mark.
3899 As swap utilization increases towards this high-water mark object
3900 eviction becomes more agressive.
3902 The value difference in percentages between low- and high-water
3903 marks represent an eviction rate of 300 objects per second and
3904 the rate continues to scale in agressiveness by multiples of
3905 this above the high-water mark.
3907 Defaults are 90% and 95%. If you have a large cache, 5% could be
3908 hundreds of MB. If this is the case you may wish to set these
3909 numbers closer together.
3911 See also cache_swap_low and cache_replacement_policy
3916 -----------------------------------------------------------------------------
3923 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
3927 logformat <name> <format specification>
3929 Defines an access log format.
3931 The <format specification> is a string with embedded % format codes
3933 % format codes all follow the same basic structure where all but
3934 the formatcode is optional. Output strings are automatically escaped
3935 as required according to their context and the output format
3936 modifiers are usually not needed, but can be specified if an explicit
3937 output format is desired.
3939 % ["|[|'|#|/] [-] [[0]width] [{arg}] formatcode [{arg}]
3941 " output in quoted string format
3942 [ output in squid text log format as used by log_mime_hdrs
3943 # output in URL quoted format
3944 / output in shell \-escaped format
3949 width minimum and/or maximum field width:
3950 [width_min][.width_max]
3951 When minimum starts with 0, the field is zero-padded.
3952 String values exceeding maximum width are truncated.
3954 {arg} argument such as header name etc. This field may be
3955 placed before or after the token, but not both at once.
3959 % a literal % character
3960 sn Unique sequence number per log line entry
3961 err_code The ID of an error response served by Squid or
3962 a similar internal error identifier.
3963 err_detail Additional err_code-dependent error information.
3964 note The annotation specified by the argument. Also
3965 logs the adaptation meta headers set by the
3966 adaptation_meta configuration parameter.
3967 If no argument given all annotations logged.
3968 The argument may include a separator to use with
3971 By default, multiple note values are separated with ","
3972 and multiple notes are separated with "\r\n".
3973 When logging named notes with %{name}note, the
3974 explicitly configured separator is used between note
3975 values. When logging all notes with %note, the
3976 explicitly configured separator is used between
3977 individual notes. There is currently no way to
3978 specify both value and notes separators when logging
3979 all notes with %note.
3981 Connection related format codes:
3983 >a Client source IP address
3985 >p Client source port
3986 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3987 >la Local IP address the client connected to
3988 >lp Local port number the client connected to
3989 >qos Client connection TOS/DSCP value set by Squid
3990 >nfmark Client connection netfilter mark set by Squid
3992 la Local listening IP address the client connection was connected to.
3993 lp Local listening port number the client connection was connected to.
3995 <a Server IP address of the last server or peer connection
3996 <A Server FQDN or peer name
3997 <p Server port number of the last server or peer connection
3998 <la Local IP address of the last server or peer connection
3999 <lp Local port number of the last server or peer connection
4000 <qos Server connection TOS/DSCP value set by Squid
4001 <nfmark Server connection netfilter mark set by Squid
4003 Time related format codes:
4005 ts Seconds since epoch
4006 tu subsecond time (milliseconds)
4007 tl Local time. Optional strftime format argument
4008 default %d/%b/%Y:%H:%M:%S %z
4009 tg GMT time. Optional strftime format argument
4010 default %d/%b/%Y:%H:%M:%S %z
4011 tr Response time (milliseconds)
4012 dt Total time spent making DNS lookups (milliseconds)
4013 tS Approximate master transaction start time in
4014 <full seconds since epoch>.<fractional seconds> format.
4015 Currently, Squid considers the master transaction
4016 started when a complete HTTP request header initiating
4017 the transaction is received from the client. This is
4018 the same value that Squid uses to calculate transaction
4019 response time when logging %tr to access.log. Currently,
4020 Squid uses millisecond resolution for %tS values,
4021 similar to the default access.log "current time" field
4024 Access Control related format codes:
4026 et Tag returned by external acl
4027 ea Log string returned by external acl
4028 un User name (any available)
4029 ul User name from authentication
4030 ue User name from external acl helper
4031 ui User name from ident
4032 un A user name. Expands to the first available name
4033 from the following list of information sources:
4034 - authenticated user name, like %ul
4035 - user name supplied by an external ACL, like %ue
4036 - SSL client name, like %us
4037 - ident user name, like %ui
4038 credentials Client credentials. The exact meaning depends on
4039 the authentication scheme: For Basic authentication,
4040 it is the password; for Digest, the realm sent by the
4041 client; for NTLM and Negotiate, the client challenge
4042 or client credentials prefixed with "YR " or "KK ".
4044 HTTP related format codes:
4048 [http::]rm Request method (GET/POST etc)
4049 [http::]>rm Request method from client
4050 [http::]<rm Request method sent to server or peer
4051 [http::]ru Request URL from client (historic, filtered for logging)
4052 [http::]>ru Request URL from client
4053 [http::]<ru Request URL sent to server or peer
4054 [http::]>rs Request URL scheme from client
4055 [http::]<rs Request URL scheme sent to server or peer
4056 [http::]>rd Request URL domain from client
4057 [http::]<rd Request URL domain sent to server or peer
4058 [http::]>rP Request URL port from client
4059 [http::]<rP Request URL port sent to server or peer
4060 [http::]rp Request URL path excluding hostname
4061 [http::]>rp Request URL path excluding hostname from client
4062 [http::]<rp Request URL path excluding hostname sent to server or peer
4063 [http::]rv Request protocol version
4064 [http::]>rv Request protocol version from client
4065 [http::]<rv Request protocol version sent to server or peer
4067 [http::]>h Original received request header.
4068 Usually differs from the request header sent by
4069 Squid, although most fields are often preserved.
4070 Accepts optional header field name/value filter
4071 argument using name[:[separator]element] format.
4072 [http::]>ha Received request header after adaptation and
4073 redirection (pre-cache REQMOD vectoring point).
4074 Usually differs from the request header sent by
4075 Squid, although most fields are often preserved.
4076 Optional header name argument as for >h
4080 [http::]<Hs HTTP status code received from the next hop
4081 [http::]>Hs HTTP status code sent to the client
4083 [http::]<h Reply header. Optional header name argument
4086 [http::]mt MIME content type
4091 [http::]st Total size of request + reply traffic with client
4092 [http::]>st Total size of request received from client.
4093 Excluding chunked encoding bytes.
4094 [http::]<st Total size of reply sent to client (after adaptation)
4096 [http::]>sh Size of request headers received from client
4097 [http::]<sh Size of reply headers sent to client (after adaptation)
4099 [http::]<sH Reply high offset sent
4100 [http::]<sS Upstream object size
4102 [http::]<bs Number of HTTP-equivalent message body bytes
4103 received from the next hop, excluding chunked
4104 transfer encoding and control messages.
4105 Generated FTP/Gopher listings are treated as
4110 [http::]<pt Peer response time in milliseconds. The timer starts
4111 when the last request byte is sent to the next hop
4112 and stops when the last response byte is received.
4113 [http::]<tt Total time in milliseconds. The timer
4114 starts with the first connect request (or write I/O)
4115 sent to the first selected peer. The timer stops
4116 with the last I/O with the last peer.
4118 Squid handling related format codes:
4120 Ss Squid request status (TCP_MISS etc)
4121 Sh Squid hierarchy status (DEFAULT_PARENT etc)
4123 SSL-related format codes:
4125 ssl::bump_mode SslBump decision for the transaction:
4127 For CONNECT requests that initiated bumping of
4128 a connection and for any request received on
4129 an already bumped connection, Squid logs the
4130 corresponding SslBump mode ("server-first" or
4131 "client-first"). See the ssl_bump option for
4132 more information about these modes.
4134 A "none" token is logged for requests that
4135 triggered "ssl_bump" ACL evaluation matching
4136 either a "none" rule or no rules at all.
4138 In all other cases, a single dash ("-") is
4141 ssl::>sni SSL client SNI sent to Squid. Available only
4142 after the peek, stare, or splice SSL bumping
4146 The Subject field of the received client
4147 SSL certificate or a dash ('-') if Squid has
4148 received an invalid/malformed certificate or
4149 no certificate at all. Consider encoding the
4150 logged value because Subject often has spaces.
4153 The Issuer field of the received client
4154 SSL certificate or a dash ('-') if Squid has
4155 received an invalid/malformed certificate or
4156 no certificate at all. Consider encoding the
4157 logged value because Issuer often has spaces.
4160 The list of certificate validation errors
4161 detected by Squid (including OpenSSL and
4162 certificate validation helper components). The
4163 errors are listed in the discovery order. By
4164 default, the error codes are separated by ':'.
4165 Accepts an optional separator argument.
4167 If ICAP is enabled, the following code becomes available (as
4168 well as ICAP log codes documented with the icap_log option):
4170 icap::tt Total ICAP processing time for the HTTP
4171 transaction. The timer ticks when ICAP
4172 ACLs are checked and when ICAP
4173 transaction is in progress.
4175 If adaptation is enabled the following codes become available:
4177 adapt::<last_h The header of the last ICAP response or
4178 meta-information from the last eCAP
4179 transaction related to the HTTP transaction.
4180 Like <h, accepts an optional header name
4183 adapt::sum_trs Summed adaptation transaction response
4184 times recorded as a comma-separated list in
4185 the order of transaction start time. Each time
4186 value is recorded as an integer number,
4187 representing response time of one or more
4188 adaptation (ICAP or eCAP) transaction in
4189 milliseconds. When a failed transaction is
4190 being retried or repeated, its time is not
4191 logged individually but added to the
4192 replacement (next) transaction. See also:
4195 adapt::all_trs All adaptation transaction response times.
4196 Same as adaptation_strs but response times of
4197 individual transactions are never added
4198 together. Instead, all transaction response
4199 times are recorded individually.
4201 You can prefix adapt::*_trs format codes with adaptation
4202 service name in curly braces to record response time(s) specific
4203 to that service. For example: %{my_service}adapt::sum_trs
4205 The default formats available (which do not need re-defining) are:
4207 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
4208 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
4209 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
4210 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
4211 logformat useragent %>a [%tl] "%{User-Agent}>h"
4213 NOTE: When the log_mime_hdrs directive is set to ON.
4214 The squid, common and combined formats have a safely encoded copy
4215 of the mime headers appended to each line within a pair of brackets.
4217 NOTE: The common and combined formats are not quite true to the Apache definition.
4218 The logs from Squid contain an extra status and hierarchy code appended.
4222 NAME: access_log cache_access_log
4224 LOC: Config.Log.accesslogs
4225 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
4227 Configures whether and how Squid logs HTTP and ICP transactions.
4228 If access logging is enabled, a single line is logged for every
4229 matching HTTP or ICP request. The recommended directive formats are:
4231 access_log <module>:<place> [option ...] [acl acl ...]
4232 access_log none [acl acl ...]
4234 The following directive format is accepted but may be deprecated:
4235 access_log <module>:<place> [<logformat name> [acl acl ...]]
4237 In most cases, the first ACL name must not contain the '=' character
4238 and should not be equal to an existing logformat name. You can always
4239 start with an 'all' ACL to work around those restrictions.
4241 Will log to the specified module:place using the specified format (which
4242 must be defined in a logformat directive) those entries which match
4243 ALL the acl's specified (which must be defined in acl clauses).
4244 If no acl is specified, all requests will be logged to this destination.
4246 ===== Available options for the recommended directive format =====
4248 logformat=name Names log line format (either built-in or
4249 defined by a logformat directive). Defaults
4252 buffer-size=64KB Defines approximate buffering limit for log
4253 records (see buffered_logs). Squid should not
4254 keep more than the specified size and, hence,
4255 should flush records before the buffer becomes
4256 full to avoid overflows under normal
4257 conditions (the exact flushing algorithm is
4258 module-dependent though). The on-error option
4259 controls overflow handling.
4261 on-error=die|drop Defines action on unrecoverable errors. The
4262 'drop' action ignores (i.e., does not log)
4263 affected log records. The default 'die' action
4264 kills the affected worker. The drop action
4265 support has not been tested for modules other
4268 rotate=N Specifies the number of log file rotations to
4269 make when you run 'squid -k rotate'. The default
4270 is to obey the logfile_rotate directive. Setting
4271 rotate=0 will disable the file name rotation,
4272 but the log files are still closed and re-opened.
4273 This will enable you to rename the logfiles
4274 yourself just before sending the rotate signal.
4275 Only supported by the stdio module.
4277 ===== Modules Currently available =====
4279 none Do not log any requests matching these ACL.
4280 Do not specify Place or logformat name.
4282 stdio Write each log line to disk immediately at the completion of
4284 Place: the filename and path to be written.
4286 daemon Very similar to stdio. But instead of writing to disk the log
4287 line is passed to a daemon helper for asychronous handling instead.
4288 Place: varies depending on the daemon.
4290 log_file_daemon Place: the file name and path to be written.
4292 syslog To log each request via syslog facility.
4293 Place: The syslog facility and priority level for these entries.
4294 Place Format: facility.priority
4296 where facility could be any of:
4297 authpriv, daemon, local0 ... local7 or user.
4299 And priority could be any of:
4300 err, warning, notice, info, debug.
4302 udp To send each log line as text data to a UDP receiver.
4303 Place: The destination host name or IP and port.
4304 Place Format: //host:port
4306 tcp To send each log line as text data to a TCP receiver.
4307 Lines may be accumulated before sending (see buffered_logs).
4308 Place: The destination host name or IP and port.
4309 Place Format: //host:port
4312 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4318 LOC: Config.Log.icaplogs
4321 ICAP log files record ICAP transaction summaries, one line per
4324 The icap_log option format is:
4325 icap_log <filepath> [<logformat name> [acl acl ...]]
4326 icap_log none [acl acl ...]]
4328 Please see access_log option documentation for details. The two
4329 kinds of logs share the overall configuration approach and many
4332 ICAP processing of a single HTTP message or transaction may
4333 require multiple ICAP transactions. In such cases, multiple
4334 ICAP transaction log lines will correspond to a single access
4337 ICAP log uses logformat codes that make sense for an ICAP
4338 transaction. Header-related codes are applied to the HTTP header
4339 embedded in an ICAP server response, with the following caveats:
4340 For REQMOD, there is no HTTP response header unless the ICAP
4341 server performed request satisfaction. For RESPMOD, the HTTP
4342 request header is the header sent to the ICAP server. For
4343 OPTIONS, there are no HTTP headers.
4345 The following format codes are also available for ICAP logs:
4347 icap::<A ICAP server IP address. Similar to <A.
4349 icap::<service_name ICAP service name from the icap_service
4350 option in Squid configuration file.
4352 icap::ru ICAP Request-URI. Similar to ru.
4354 icap::rm ICAP request method (REQMOD, RESPMOD, or
4355 OPTIONS). Similar to existing rm.
4357 icap::>st Bytes sent to the ICAP server (TCP payload
4358 only; i.e., what Squid writes to the socket).
4360 icap::<st Bytes received from the ICAP server (TCP
4361 payload only; i.e., what Squid reads from
4364 icap::<bs Number of message body bytes received from the
4365 ICAP server. ICAP message body, if any, usually
4366 includes encapsulated HTTP message headers and
4367 possibly encapsulated HTTP message body. The
4368 HTTP body part is dechunked before its size is
4371 icap::tr Transaction response time (in
4372 milliseconds). The timer starts when
4373 the ICAP transaction is created and
4374 stops when the transaction is completed.
4377 icap::tio Transaction I/O time (in milliseconds). The
4378 timer starts when the first ICAP request
4379 byte is scheduled for sending. The timers
4380 stops when the last byte of the ICAP response
4383 icap::to Transaction outcome: ICAP_ERR* for all
4384 transaction errors, ICAP_OPT for OPTION
4385 transactions, ICAP_ECHO for 204
4386 responses, ICAP_MOD for message
4387 modification, and ICAP_SAT for request
4388 satisfaction. Similar to Ss.
4390 icap::Hs ICAP response status code. Similar to Hs.
4392 icap::>h ICAP request header(s). Similar to >h.
4394 icap::<h ICAP response header(s). Similar to <h.
4396 The default ICAP log format, which can be used without an explicit
4397 definition, is called icap_squid:
4399 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
4401 See also: logformat, log_icap, and %adapt::<last_h
4404 NAME: logfile_daemon
4406 DEFAULT: @DEFAULT_LOGFILED@
4407 LOC: Log::TheConfig.logfile_daemon
4409 Specify the path to the logfile-writing daemon. This daemon is
4410 used to write the access and store logs, if configured.
4412 Squid sends a number of commands to the log daemon:
4413 L<data>\n - logfile data
4418 r<n>\n - set rotate count to <n>
4419 b<n>\n - 1 = buffer output, 0 = don't buffer output
4421 No responses is expected.
4424 NAME: stats_collection
4426 LOC: Config.accessList.stats_collection
4428 DEFAULT_DOC: Allow logging for all transactions.
4429 COMMENT: allow|deny acl acl...
4431 This options allows you to control which requests gets accounted
4432 in performance counters.
4434 This clause only supports fast acl types.
4435 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4438 NAME: cache_store_log
4441 LOC: Config.Log.store
4443 Logs the activities of the storage manager. Shows which
4444 objects are ejected from the cache, and which objects are
4445 saved and for how long.
4446 There are not really utilities to analyze this data, so you can safely
4447 disable it (the default).
4449 Store log uses modular logging outputs. See access_log for the list
4450 of modules supported.
4453 cache_store_log stdio:@DEFAULT_STORE_LOG@
4454 cache_store_log daemon:@DEFAULT_STORE_LOG@
4457 NAME: cache_swap_state cache_swap_log
4459 LOC: Config.Log.swap
4461 DEFAULT_DOC: Store the journal inside its cache_dir
4463 Location for the cache "swap.state" file. This index file holds
4464 the metadata of objects saved on disk. It is used to rebuild
4465 the cache during startup. Normally this file resides in each
4466 'cache_dir' directory, but you may specify an alternate
4467 pathname here. Note you must give a full filename, not just
4468 a directory. Since this is the index for the whole object
4469 list you CANNOT periodically rotate it!
4471 If %s can be used in the file name it will be replaced with a
4472 a representation of the cache_dir name where each / is replaced
4473 with '.'. This is needed to allow adding/removing cache_dir
4474 lines when cache_swap_log is being used.
4476 If have more than one 'cache_dir', and %s is not used in the name
4477 these swap logs will have names such as:
4483 The numbered extension (which is added automatically)
4484 corresponds to the order of the 'cache_dir' lines in this
4485 configuration file. If you change the order of the 'cache_dir'
4486 lines in this file, these index files will NOT correspond to
4487 the correct 'cache_dir' entry (unless you manually rename
4488 them). We recommend you do NOT use this option. It is
4489 better to keep these index files in each 'cache_dir' directory.
4492 NAME: logfile_rotate
4495 LOC: Config.Log.rotateNumber
4497 Specifies the default number of logfile rotations to make when you
4498 type 'squid -k rotate'. The default is 10, which will rotate
4499 with extensions 0 through 9. Setting logfile_rotate to 0 will
4500 disable the file name rotation, but the logfiles are still closed
4501 and re-opened. This will enable you to rename the logfiles
4502 yourself just before sending the rotate signal.
4504 Note, from Squid-3.1 this option is only a default for cache.log,
4505 that log can be rotated separately by using debug_options.
4507 Note, from Squid-3.6 this option is only a default for access.log
4508 recorded by stdio: module. Those logs can be rotated separately by
4509 using the rotate=N option on their access_log directive.
4511 Note, the 'squid -k rotate' command normally sends a USR1
4512 signal to the running squid process. In certain situations
4513 (e.g. on Linux with Async I/O), USR1 is used for other
4514 purposes, so -k rotate uses another signal. It is best to get
4515 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4522 DEFAULT: @DEFAULT_MIME_TABLE@
4523 LOC: Config.mimeTablePathname
4525 Path to Squid's icon configuration file.
4527 You shouldn't need to change this, but the default file contains
4528 examples and formatting information if you do.
4534 LOC: Config.onoff.log_mime_hdrs
4537 The Cache can record both the request and the response MIME
4538 headers for each HTTP transaction. The headers are encoded
4539 safely and will appear as two bracketed fields at the end of
4540 the access log (for either the native or httpd-emulated log
4541 formats). To enable this logging set log_mime_hdrs to 'on'.
4546 DEFAULT: @DEFAULT_PID_FILE@
4547 LOC: Config.pidFilename
4549 A filename to write the process-id to. To disable, enter "none".
4552 NAME: client_netmask
4554 LOC: Config.Addrs.client_netmask
4556 DEFAULT_DOC: Log full client IP address
4558 A netmask for client addresses in logfiles and cachemgr output.
4559 Change this to protect the privacy of your cache clients.
4560 A netmask of 255.255.255.0 will log all IP's in that range with
4561 the last digit set to '0'.
4564 NAME: strip_query_terms
4566 LOC: Config.onoff.strip_query_terms
4569 By default, Squid strips query terms from requested URLs before
4570 logging. This protects your user's privacy and reduces log size.
4572 When investigating HIT/MISS or other caching behaviour you
4573 will need to disable this to see the full URL used by Squid.
4580 LOC: Config.onoff.buffered_logs
4582 Whether to write/send access_log records ASAP or accumulate them and
4583 then write/send them in larger chunks. Buffering may improve
4584 performance because it decreases the number of I/Os. However,
4585 buffering increases the delay before log records become available to
4586 the final recipient (e.g., a disk file or logging daemon) and,
4587 hence, increases the risk of log records loss.
4589 Note that even when buffered_logs are off, Squid may have to buffer
4590 records if it cannot write/send them immediately due to pending I/Os
4591 (e.g., the I/O writing the previous log record) or connectivity loss.
4593 Currently honored by 'daemon' and 'tcp' access_log modules only.
4596 NAME: netdb_filename
4598 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4599 LOC: Config.netdbFilename
4602 Where Squid stores it's netdb journal.
4603 When enabled this journal preserves netdb state between restarts.
4605 To disable, enter "none".
4609 OPTIONS FOR TROUBLESHOOTING
4610 -----------------------------------------------------------------------------
4615 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4616 LOC: Debug::cache_log
4618 Squid administrative logging file.
4620 This is where general information about Squid behavior goes. You can
4621 increase the amount of data logged to this file and how often it is
4622 rotated with "debug_options"
4628 DEFAULT_DOC: Log all critical and important messages.
4629 LOC: Debug::debugOptions
4631 Logging options are set as section,level where each source file
4632 is assigned a unique section. Lower levels result in less
4633 output, Full debugging (level 9) can result in a very large
4634 log file, so be careful.
4636 The magic word "ALL" sets debugging levels for all sections.
4637 The default is to run with "ALL,1" to record important warnings.
4639 The rotate=N option can be used to keep more or less of these logs
4640 than would otherwise be kept by logfile_rotate.
4641 For most uses a single log should be enough to monitor current
4642 events affecting Squid.
4647 LOC: Config.coredump_dir
4648 DEFAULT_IF_NONE: none
4649 DEFAULT_DOC: Use the directory from where Squid was started.
4651 By default Squid leaves core files in the directory from where
4652 it was started. If you set 'coredump_dir' to a directory
4653 that exists, Squid will chdir() to that directory at startup
4654 and coredump files will be left there.
4658 # Leave coredumps in the first cache dir
4659 coredump_dir @DEFAULT_SWAP_DIR@
4665 OPTIONS FOR FTP GATEWAYING
4666 -----------------------------------------------------------------------------
4672 LOC: Config.Ftp.anon_user
4674 If you want the anonymous login password to be more informative
4675 (and enable the use of picky FTP servers), set this to something
4676 reasonable for your domain, like wwwuser@somewhere.net
4678 The reason why this is domainless by default is the
4679 request can be made on the behalf of a user in any domain,
4680 depending on how the cache is used.
4681 Some FTP server also validate the email address is valid
4682 (for example perl.com).
4688 LOC: Config.Ftp.passive
4690 If your firewall does not allow Squid to use passive
4691 connections, turn off this option.
4693 Use of ftp_epsv_all option requires this to be ON.
4699 LOC: Config.Ftp.epsv_all
4701 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4703 NATs may be able to put the connection on a "fast path" through the
4704 translator, as the EPRT command will never be used and therefore,
4705 translation of the data portion of the segments will never be needed.
4707 When a client only expects to do two-way FTP transfers this may be
4709 If squid finds that it must do a three-way FTP transfer after issuing
4710 an EPSV ALL command, the FTP session will fail.
4712 If you have any doubts about this option do not use it.
4713 Squid will nicely attempt all other connection methods.
4715 Requires ftp_passive to be ON (default) for any effect.
4721 LOC: Config.accessList.ftp_epsv
4723 FTP Protocol extensions permit the use of a special "EPSV" command.
4725 NATs may be able to put the connection on a "fast path" through the
4726 translator using EPSV, as the EPRT command will never be used
4727 and therefore, translation of the data portion of the segments
4728 will never be needed.
4730 EPSV is often required to interoperate with FTP servers on IPv6
4731 networks. On the other hand, it may break some IPv4 servers.
4733 By default, EPSV may try EPSV with any FTP server. To fine tune
4734 that decision, you may restrict EPSV to certain clients or servers
4737 ftp_epsv allow|deny al1 acl2 ...
4739 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
4741 Only fast ACLs are supported.
4742 Requires ftp_passive to be ON (default) for any effect.
4748 LOC: Config.Ftp.eprt
4750 FTP Protocol extensions permit the use of a special "EPRT" command.
4752 This extension provides a protocol neutral alternative to the
4753 IPv4-only PORT command. When supported it enables active FTP data
4754 channels over IPv6 and efficient NAT handling.
4756 Turning this OFF will prevent EPRT being attempted and will skip
4757 straight to using PORT for IPv4 servers.
4759 Some devices are known to not handle this extension correctly and
4760 may result in crashes. Devices which suport EPRT enough to fail
4761 cleanly will result in Squid attempting PORT anyway. This directive
4762 should only be disabled when EPRT results in device failures.
4764 WARNING: Doing so will convert Squid back to the old behavior with all
4765 the related problems with external NAT devices/layers and IPv4-only FTP.
4768 NAME: ftp_sanitycheck
4771 LOC: Config.Ftp.sanitycheck
4773 For security and data integrity reasons Squid by default performs
4774 sanity checks of the addresses of FTP data connections ensure the
4775 data connection is to the requested server. If you need to allow
4776 FTP connections to servers using another IP address for the data
4777 connection turn this off.
4780 NAME: ftp_telnet_protocol
4783 LOC: Config.Ftp.telnet
4785 The FTP protocol is officially defined to use the telnet protocol
4786 as transport channel for the control connection. However, many
4787 implementations are broken and does not respect this aspect of
4790 If you have trouble accessing files with ASCII code 255 in the
4791 path or similar problems involving this ASCII code you can
4792 try setting this directive to off. If that helps, report to the
4793 operator of the FTP server in question that their FTP server
4794 is broken and does not follow the FTP standard.
4798 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4799 -----------------------------------------------------------------------------
4804 DEFAULT: @DEFAULT_DISKD@
4805 LOC: Config.Program.diskd
4807 Specify the location of the diskd executable.
4808 Note this is only useful if you have compiled in
4809 diskd as one of the store io modules.
4812 NAME: unlinkd_program
4815 DEFAULT: @DEFAULT_UNLINKD@
4816 LOC: Config.Program.unlinkd
4818 Specify the location of the executable for file deletion process.
4821 NAME: pinger_program
4824 DEFAULT: @DEFAULT_PINGER@
4827 Specify the location of the executable for the pinger process.
4836 Control whether the pinger is active at run-time.
4837 Enables turning ICMP pinger on and off with a simple
4838 squid -k reconfigure.
4843 OPTIONS FOR URL REWRITING
4844 -----------------------------------------------------------------------------
4847 NAME: url_rewrite_program redirect_program
4849 LOC: Config.Program.redirect
4852 Specify the location of the executable URL rewriter to use.
4853 Since they can perform almost any function there isn't one included.
4855 For each requested URL, the rewriter will receive on line with the format
4857 [channel-ID <SP>] URL [<SP> extras]<NL>
4859 See url_rewrite_extras on how to send "extras" with optional values to
4861 After processing the request the helper must reply using the following format:
4863 [channel-ID <SP>] result [<SP> kv-pairs]
4865 The result code can be:
4867 OK status=30N url="..."
4868 Redirect the URL to the one supplied in 'url='.
4869 'status=' is optional and contains the status code to send
4870 the client in Squids HTTP response. It must be one of the
4871 HTTP redirect status codes: 301, 302, 303, 307, 308.
4872 When no status is given Squid will use 302.
4874 OK rewrite-url="..."
4875 Rewrite the URL to the one supplied in 'rewrite-url='.
4876 The new URL is fetched directly by Squid and returned to
4877 the client as the response to its request.
4880 When neither of url= and rewrite-url= are sent Squid does
4884 Do not change the URL.
4887 An internal error occurred in the helper, preventing
4888 a result being identified. The 'message=' key name is
4889 reserved for delivering a log message.
4892 In addition to the above kv-pairs Squid also understands the following
4893 optional kv-pairs received from URL rewriters:
4895 Associates a TAG with the client TCP connection.
4896 The TAG is treated as a regular annotation but persists across
4897 future requests on the client connection rather than just the
4898 current request. A helper may update the TAG during subsequent
4899 requests be returning a new kv-pair.
4901 When using the concurrency= option the protocol is changed by
4902 introducing a query channel tag in front of the request/response.
4903 The query channel tag is a number between 0 and concurrency-1.
4904 This value must be echoed back unchanged to Squid as the first part
4905 of the response relating to its request.
4907 WARNING: URL re-writing ability should be avoided whenever possible.
4908 Use the URL redirect form of response instead.
4910 Re-write creates a difference in the state held by the client
4911 and server. Possibly causing confusion when the server response
4912 contains snippets of its view state. Embeded URLs, response
4913 and content Location headers, etc. are not re-written by this
4916 By default, a URL rewriter is not used.
4919 NAME: url_rewrite_children redirect_children
4920 TYPE: HelperChildConfig
4921 DEFAULT: 20 startup=0 idle=1 concurrency=0
4922 LOC: Config.redirectChildren
4924 The maximum number of redirector processes to spawn. If you limit
4925 it too few Squid will have to wait for them to process a backlog of
4926 URLs, slowing it down. If you allow too many they will use RAM
4927 and other system resources noticably.
4929 The startup= and idle= options allow some measure of skew in your
4934 Sets a minimum of how many processes are to be spawned when Squid
4935 starts or reconfigures. When set to zero the first request will
4936 cause spawning of the first child process to handle it.
4938 Starting too few will cause an initial slowdown in traffic as Squid
4939 attempts to simultaneously spawn enough processes to cope.
4943 Sets a minimum of how many processes Squid is to try and keep available
4944 at all times. When traffic begins to rise above what the existing
4945 processes can handle this many more will be spawned up to the maximum
4946 configured. A minimum setting of 1 is required.
4950 The number of requests each redirector helper can handle in
4951 parallel. Defaults to 0 which indicates the redirector
4952 is a old-style single threaded redirector.
4954 When this directive is set to a value >= 1 then the protocol
4955 used to communicate with the helper is modified to include
4956 an ID in front of the request/response. The ID from the request
4957 must be echoed back with the response to that request.
4961 Sets the maximum number of queued requests.
4962 If the queued requests exceed queue size and redirector_bypass
4963 configuration option is set, then redirector is bypassed. Otherwise, if
4964 overloading persists squid may abort its operation.
4965 The default value is set to 2*numberofchildren.
4968 NAME: url_rewrite_host_header redirect_rewrites_host_header
4971 LOC: Config.onoff.redir_rewrites_host
4973 To preserve same-origin security policies in browsers and
4974 prevent Host: header forgery by redirectors Squid rewrites
4975 any Host: header in redirected requests.
4977 If you are running an accelerator this may not be a wanted
4978 effect of a redirector. This directive enables you disable
4979 Host: alteration in reverse-proxy traffic.
4981 WARNING: Entries are cached on the result of the URL rewriting
4982 process, so be careful if you have domain-virtual hosts.
4984 WARNING: Squid and other software verifies the URL and Host
4985 are matching, so be careful not to relay through other proxies
4986 or inspecting firewalls with this disabled.
4989 NAME: url_rewrite_access redirector_access
4992 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4993 LOC: Config.accessList.redirector
4995 If defined, this access list specifies which requests are
4996 sent to the redirector processes.
4998 This clause supports both fast and slow acl types.
4999 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5002 NAME: url_rewrite_bypass redirector_bypass
5004 LOC: Config.onoff.redirector_bypass
5007 When this is 'on', a request will not go through the
5008 redirector if all the helpers are busy. If this is 'off'
5009 and the redirector queue grows too large, Squid will exit
5010 with a FATAL error and ask you to increase the number of
5011 redirectors. You should only enable this if the redirectors
5012 are not critical to your caching system. If you use
5013 redirectors for access control, and you enable this option,
5014 users may have access to pages they should not
5015 be allowed to request.
5016 This options sets default queue-size option of the url_rewrite_children
5020 NAME: url_rewrite_extras
5021 TYPE: TokenOrQuotedString
5022 LOC: Config.redirector_extras
5023 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5025 Specifies a string to be append to request line format for the
5026 rewriter helper. "Quoted" format values may contain spaces and
5027 logformat %macros. In theory, any logformat %macro can be used.
5028 In practice, a %macro expands as a dash (-) if the helper request is
5029 sent before the required macro information is available to Squid.
5032 NAME: url_rewrite_timeout
5033 TYPE: UrlHelperTimeout
5034 LOC: Config.onUrlRewriteTimeout
5036 DEFAULT_DOC: Squid waits for the helper response forever
5038 Squid times active requests to redirector. The timeout value and Squid
5039 reaction to a timed out request are configurable using the following
5042 url_rewrite_timeout timeout time-units on_timeout=<action> [response=<quoted-response>]
5044 supported timeout actions:
5045 fail Squid return a ERR_GATEWAY_FAILURE error page
5047 bypass Do not re-write the URL
5049 retry Send the lookup to the helper again
5051 use_configured_response
5052 Use the <quoted-response> as helper response
5056 OPTIONS FOR STORE ID
5057 -----------------------------------------------------------------------------
5060 NAME: store_id_program storeurl_rewrite_program
5062 LOC: Config.Program.store_id
5065 Specify the location of the executable StoreID helper to use.
5066 Since they can perform almost any function there isn't one included.
5068 For each requested URL, the helper will receive one line with the format
5070 [channel-ID <SP>] URL [<SP> extras]<NL>
5073 After processing the request the helper must reply using the following format:
5075 [channel-ID <SP>] result [<SP> kv-pairs]
5077 The result code can be:
5080 Use the StoreID supplied in 'store-id='.
5083 The default is to use HTTP request URL as the store ID.
5086 An internal error occured in the helper, preventing
5087 a result being identified.
5089 In addition to the above kv-pairs Squid also understands the following
5090 optional kv-pairs received from URL rewriters:
5092 Associates a TAG with the client TCP connection.
5093 Please see url_rewrite_program related documentation for this
5096 Helper programs should be prepared to receive and possibly ignore
5097 additional whitespace-separated tokens on each input line.
5099 When using the concurrency= option the protocol is changed by
5100 introducing a query channel tag in front of the request/response.
5101 The query channel tag is a number between 0 and concurrency-1.
5102 This value must be echoed back unchanged to Squid as the first part
5103 of the response relating to its request.
5105 NOTE: when using StoreID refresh_pattern will apply to the StoreID
5106 returned from the helper and not the URL.
5108 WARNING: Wrong StoreID value returned by a careless helper may result
5109 in the wrong cached response returned to the user.
5111 By default, a StoreID helper is not used.
5114 NAME: store_id_extras
5115 TYPE: TokenOrQuotedString
5116 LOC: Config.storeId_extras
5117 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5119 Specifies a string to be append to request line format for the
5120 StoreId helper. "Quoted" format values may contain spaces and
5121 logformat %macros. In theory, any logformat %macro can be used.
5122 In practice, a %macro expands as a dash (-) if the helper request is
5123 sent before the required macro information is available to Squid.
5126 NAME: store_id_children storeurl_rewrite_children
5127 TYPE: HelperChildConfig
5128 DEFAULT: 20 startup=0 idle=1 concurrency=0
5129 LOC: Config.storeIdChildren
5131 The maximum number of StoreID helper processes to spawn. If you limit
5132 it too few Squid will have to wait for them to process a backlog of
5133 requests, slowing it down. If you allow too many they will use RAM
5134 and other system resources noticably.
5136 The startup= and idle= options allow some measure of skew in your
5141 Sets a minimum of how many processes are to be spawned when Squid
5142 starts or reconfigures. When set to zero the first request will
5143 cause spawning of the first child process to handle it.
5145 Starting too few will cause an initial slowdown in traffic as Squid
5146 attempts to simultaneously spawn enough processes to cope.
5150 Sets a minimum of how many processes Squid is to try and keep available
5151 at all times. When traffic begins to rise above what the existing
5152 processes can handle this many more will be spawned up to the maximum
5153 configured. A minimum setting of 1 is required.
5157 The number of requests each storeID helper can handle in
5158 parallel. Defaults to 0 which indicates the helper
5159 is a old-style single threaded program.
5161 When this directive is set to a value >= 1 then the protocol
5162 used to communicate with the helper is modified to include
5163 an ID in front of the request/response. The ID from the request
5164 must be echoed back with the response to that request.
5168 Sets the maximum number of queued requests.
5169 If the queued requests exceed queue size and store_id_bypass
5170 configuration option is set, then storeID helper is bypassed. Otherwise,
5171 if overloading persists squid may abort its operation.
5172 The default value is set to 2*numberofchildren.
5175 NAME: store_id_access storeurl_rewrite_access
5178 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5179 LOC: Config.accessList.store_id
5181 If defined, this access list specifies which requests are
5182 sent to the StoreID processes. By default all requests
5185 This clause supports both fast and slow acl types.
5186 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5189 NAME: store_id_bypass storeurl_rewrite_bypass
5191 LOC: Config.onoff.store_id_bypass
5194 When this is 'on', a request will not go through the
5195 helper if all helpers are busy. If this is 'off'
5196 and the helper queue grows too large, Squid will exit
5197 with a FATAL error and ask you to increase the number of
5198 helpers. You should only enable this if the helperss
5199 are not critical to your caching system. If you use
5200 helpers for critical caching components, and you enable this
5201 option, users may not get objects from cache.
5202 This options sets default queue-size option of the store_id_children
5207 OPTIONS FOR TUNING THE CACHE
5208 -----------------------------------------------------------------------------
5211 NAME: cache no_cache
5214 DEFAULT_DOC: By default, this directive is unused and has no effect.
5215 LOC: Config.accessList.noCache
5217 Requests denied by this directive will not be served from the cache
5218 and their responses will not be stored in the cache. This directive
5219 has no effect on other transactions and on already cached responses.
5221 This clause supports both fast and slow acl types.
5222 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5224 This and the two other similar caching directives listed below are
5225 checked at different transaction processing stages, have different
5226 access to response information, affect different cache operations,
5227 and differ in slow ACLs support:
5229 * cache: Checked before Squid makes a hit/miss determination.
5230 No access to reply information!
5231 Denies both serving a hit and storing a miss.
5232 Supports both fast and slow ACLs.
5233 * send_hit: Checked after a hit was detected.
5234 Has access to reply (hit) information.
5235 Denies serving a hit only.
5236 Supports fast ACLs only.
5237 * store_miss: Checked before storing a cachable miss.
5238 Has access to reply (miss) information.
5239 Denies storing a miss only.
5240 Supports fast ACLs only.
5242 If you are not sure which of the three directives to use, apply the
5243 following decision logic:
5245 * If your ACL(s) are of slow type _and_ need response info, redesign.
5246 Squid does not support that particular combination at this time.
5248 * If your directive ACL(s) are of slow type, use "cache"; and/or
5249 * if your directive ACL(s) need no response info, use "cache".
5251 * If you do not want the response cached, use store_miss; and/or
5252 * if you do not want a hit on a cached response, use send_hit.
5258 DEFAULT_DOC: By default, this directive is unused and has no effect.
5259 LOC: Config.accessList.sendHit
5261 Responses denied by this directive will not be served from the cache
5262 (but may still be cached, see store_miss). This directive has no
5263 effect on the responses it allows and on the cached objects.
5265 Please see the "cache" directive for a summary of differences among
5266 store_miss, send_hit, and cache directives.
5268 Unlike the "cache" directive, send_hit only supports fast acl
5269 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5273 # apply custom Store ID mapping to some URLs
5274 acl MapMe dstdomain .c.example.com
5275 store_id_program ...
5276 store_id_access allow MapMe
5278 # but prevent caching of special responses
5279 # such as 302 redirects that cause StoreID loops
5280 acl Ordinary http_status 200-299
5281 store_miss deny MapMe !Ordinary
5283 # and do not serve any previously stored special responses
5284 # from the cache (in case they were already cached before
5285 # the above store_miss rule was in effect).
5286 send_hit deny MapMe !Ordinary
5292 DEFAULT_DOC: By default, this directive is unused and has no effect.
5293 LOC: Config.accessList.storeMiss
5295 Responses denied by this directive will not be cached (but may still
5296 be served from the cache, see send_hit). This directive has no
5297 effect on the responses it allows and on the already cached responses.
5299 Please see the "cache" directive for a summary of differences among
5300 store_miss, send_hit, and cache directives. See the
5301 send_hit directive for a usage example.
5303 Unlike the "cache" directive, store_miss only supports fast acl
5304 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5310 LOC: Config.maxStale
5313 This option puts an upper limit on how stale content Squid
5314 will serve from the cache if cache validation fails.
5315 Can be overriden by the refresh_pattern max-stale option.
5318 NAME: refresh_pattern
5319 TYPE: refreshpattern
5323 usage: refresh_pattern [-i] regex min percent max [options]
5325 By default, regular expressions are CASE-SENSITIVE. To make
5326 them case-insensitive, use the -i option.
5328 'Min' is the time (in minutes) an object without an explicit
5329 expiry time should be considered fresh. The recommended
5330 value is 0, any higher values may cause dynamic applications
5331 to be erroneously cached unless the application designer
5332 has taken the appropriate actions.
5334 'Percent' is a percentage of the objects age (time since last
5335 modification age) an object without explicit expiry time
5336 will be considered fresh.
5338 'Max' is an upper limit on how long objects without an explicit
5339 expiry time will be considered fresh.
5341 options: override-expire
5351 override-expire enforces min age even if the server
5352 sent an explicit expiry time (e.g., with the
5353 Expires: header or Cache-Control: max-age). Doing this
5354 VIOLATES the HTTP standard. Enabling this feature
5355 could make you liable for problems which it causes.
5357 Note: override-expire does not enforce staleness - it only extends
5358 freshness / min. If the server returns a Expires time which
5359 is longer than your max time, Squid will still consider
5360 the object fresh for that period of time.
5362 override-lastmod enforces min age even on objects
5363 that were modified recently.
5365 reload-into-ims changes a client no-cache or ``reload''
5366 request for a cached entry into a conditional request using
5367 If-Modified-Since and/or If-None-Match headers, provided the
5368 cached entry has a Last-Modified and/or a strong ETag header.
5369 Doing this VIOLATES the HTTP standard. Enabling this feature
5370 could make you liable for problems which it causes.
5372 ignore-reload ignores a client no-cache or ``reload''
5373 header. Doing this VIOLATES the HTTP standard. Enabling
5374 this feature could make you liable for problems which
5377 ignore-no-store ignores any ``Cache-control: no-store''
5378 headers received from a server. Doing this VIOLATES
5379 the HTTP standard. Enabling this feature could make you
5380 liable for problems which it causes.
5382 ignore-private ignores any ``Cache-control: private''
5383 headers received from a server. Doing this VIOLATES
5384 the HTTP standard. Enabling this feature could make you
5385 liable for problems which it causes.
5387 refresh-ims causes squid to contact the origin server
5388 when a client issues an If-Modified-Since request. This
5389 ensures that the client will receive an updated version
5390 if one is available.
5392 store-stale stores responses even if they don't have explicit
5393 freshness or a validator (i.e., Last-Modified or an ETag)
5394 present, or if they're already stale. By default, Squid will
5395 not cache such responses because they usually can't be
5396 reused. Note that such responses will be stale by default.
5398 max-stale=NN provide a maximum staleness factor. Squid won't
5399 serve objects more stale than this even if it failed to
5400 validate the object. Default: use the max_stale global limit.
5402 Basically a cached object is:
5404 FRESH if expire > now, else STALE
5406 FRESH if lm-factor < percent, else STALE
5410 The refresh_pattern lines are checked in the order listed here.
5411 The first entry which matches is used. If none of the entries
5412 match the default will be used.
5414 Note, you must uncomment all the default lines if you want
5415 to change one. The default setting is only active if none is
5421 # Add any of your own refresh_pattern entries above these.
5423 refresh_pattern ^ftp: 1440 20% 10080
5424 refresh_pattern ^gopher: 1440 0% 1440
5425 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5426 refresh_pattern . 0 20% 4320
5430 NAME: quick_abort_min
5434 LOC: Config.quickAbort.min
5437 NAME: quick_abort_max
5441 LOC: Config.quickAbort.max
5444 NAME: quick_abort_pct
5448 LOC: Config.quickAbort.pct
5450 The cache by default continues downloading aborted requests
5451 which are almost completed (less than 16 KB remaining). This
5452 may be undesirable on slow (e.g. SLIP) links and/or very busy
5453 caches. Impatient users may tie up file descriptors and
5454 bandwidth by repeatedly requesting and immediately aborting
5457 When the user aborts a request, Squid will check the
5458 quick_abort values to the amount of data transferred until
5461 If the transfer has less than 'quick_abort_min' KB remaining,
5462 it will finish the retrieval.
5464 If the transfer has more than 'quick_abort_max' KB remaining,
5465 it will abort the retrieval.
5467 If more than 'quick_abort_pct' of the transfer has completed,
5468 it will finish the retrieval.
5470 If you do not want any retrieval to continue after the client
5471 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5474 If you want retrievals to always continue if they are being
5475 cached set 'quick_abort_min' to '-1 KB'.
5478 NAME: read_ahead_gap
5479 COMMENT: buffer-size
5481 LOC: Config.readAheadGap
5484 The amount of data the cache will buffer ahead of what has been
5485 sent to the client when retrieving an object from another server.
5489 IFDEF: USE_HTTP_VIOLATIONS
5492 LOC: Config.negativeTtl
5495 Set the Default Time-to-Live (TTL) for failed requests.
5496 Certain types of failures (such as "connection refused" and
5497 "404 Not Found") are able to be negatively-cached for a short time.
5498 Modern web servers should provide Expires: header, however if they
5499 do not this can provide a minimum TTL.
5500 The default is not to cache errors with unknown expiry details.
5502 Note that this is different from negative caching of DNS lookups.
5504 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5505 this feature could make you liable for problems which it
5509 NAME: positive_dns_ttl
5512 LOC: Config.positiveDnsTtl
5515 Upper limit on how long Squid will cache positive DNS responses.
5516 Default is 6 hours (360 minutes). This directive must be set
5517 larger than negative_dns_ttl.
5520 NAME: negative_dns_ttl
5523 LOC: Config.negativeDnsTtl
5526 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5527 This also sets the lower cache limit on positive lookups.
5528 Minimum value is 1 second, and it is not recommendable to go
5529 much below 10 seconds.
5532 NAME: range_offset_limit
5533 COMMENT: size [acl acl...]
5535 LOC: Config.rangeOffsetLimit
5538 usage: (size) [units] [[!]aclname]
5540 Sets an upper limit on how far (number of bytes) into the file
5541 a Range request may be to cause Squid to prefetch the whole file.
5542 If beyond this limit, Squid forwards the Range request as it is and
5543 the result is NOT cached.
5545 This is to stop a far ahead range request (lets say start at 17MB)
5546 from making Squid fetch the whole object up to that point before
5547 sending anything to the client.
5549 Multiple range_offset_limit lines may be specified, and they will
5550 be searched from top to bottom on each request until a match is found.
5551 The first match found will be used. If no line matches a request, the
5552 default limit of 0 bytes will be used.
5554 'size' is the limit specified as a number of units.
5556 'units' specifies whether to use bytes, KB, MB, etc.
5557 If no units are specified bytes are assumed.
5559 A size of 0 causes Squid to never fetch more than the
5560 client requested. (default)
5562 A size of 'none' causes Squid to always fetch the object from the
5563 beginning so it may cache the result. (2.0 style)
5565 'aclname' is the name of a defined ACL.
5567 NP: Using 'none' as the byte value here will override any quick_abort settings
5568 that may otherwise apply to the range request. The range request will
5569 be fully fetched from start to finish regardless of the client
5570 actions. This affects bandwidth usage.
5573 NAME: minimum_expiry_time
5576 LOC: Config.minimum_expiry_time
5579 The minimum caching time according to (Expires - Date)
5580 headers Squid honors if the object can't be revalidated.
5581 The default is 60 seconds.
5583 In reverse proxy environments it might be desirable to honor
5584 shorter object lifetimes. It is most likely better to make
5585 your server return a meaningful Last-Modified header however.
5587 In ESI environments where page fragments often have short
5588 lifetimes, this will often be best set to 0.
5591 NAME: store_avg_object_size
5595 LOC: Config.Store.avgObjectSize
5597 Average object size, used to estimate number of objects your
5598 cache can hold. The default is 13 KB.
5600 This is used to pre-seed the cache index memory allocation to
5601 reduce expensive reallocate operations while handling clients
5602 traffic. Too-large values may result in memory allocation during
5603 peak traffic, too-small values will result in wasted memory.
5605 Check the cache manager 'info' report metrics for the real
5606 object sizes seen by your Squid before tuning this.
5609 NAME: store_objects_per_bucket
5612 LOC: Config.Store.objectsPerBucket
5614 Target number of objects per bucket in the store hash table.
5615 Lowering this value increases the total number of buckets and
5616 also the storage maintenance rate. The default is 20.
5621 -----------------------------------------------------------------------------
5624 NAME: request_header_max_size
5628 LOC: Config.maxRequestHeaderSize
5630 This specifies the maximum size for HTTP headers in a request.
5631 Request headers are usually relatively small (about 512 bytes).
5632 Placing a limit on the request header size will catch certain
5633 bugs (for example with persistent connections) and possibly
5634 buffer-overflow or denial-of-service attacks.
5637 NAME: reply_header_max_size
5641 LOC: Config.maxReplyHeaderSize
5643 This specifies the maximum size for HTTP headers in a reply.
5644 Reply headers are usually relatively small (about 512 bytes).
5645 Placing a limit on the reply header size will catch certain
5646 bugs (for example with persistent connections) and possibly
5647 buffer-overflow or denial-of-service attacks.
5650 NAME: request_body_max_size
5654 DEFAULT_DOC: No limit.
5655 LOC: Config.maxRequestBodySize
5657 This specifies the maximum size for an HTTP request body.
5658 In other words, the maximum size of a PUT/POST request.
5659 A user who attempts to send a request with a body larger
5660 than this limit receives an "Invalid Request" error message.
5661 If you set this parameter to a zero (the default), there will
5662 be no limit imposed.
5664 See also client_request_buffer_max_size for an alternative
5665 limitation on client uploads which can be configured.
5668 NAME: client_request_buffer_max_size
5672 LOC: Config.maxRequestBufferSize
5674 This specifies the maximum buffer size of a client request.
5675 It prevents squid eating too much memory when somebody uploads
5680 IFDEF: USE_HTTP_VIOLATIONS
5683 DEFAULT_DOC: Obey RFC 2616.
5684 LOC: Config.accessList.brokenPosts
5686 A list of ACL elements which, if matched, causes Squid to send
5687 an extra CRLF pair after the body of a PUT/POST request.
5689 Some HTTP servers has broken implementations of PUT/POST,
5690 and rely on an extra CRLF pair sent by some WWW clients.
5692 Quote from RFC2616 section 4.1 on this matter:
5694 Note: certain buggy HTTP/1.0 client implementations generate an
5695 extra CRLF's after a POST request. To restate what is explicitly
5696 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5697 a request with an extra CRLF.
5699 This clause only supports fast acl types.
5700 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5703 acl buggy_server url_regex ^http://....
5704 broken_posts allow buggy_server
5707 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5710 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5712 LOC: Adaptation::Config::use_indirect_client
5714 Controls whether the indirect client IP address (instead of the direct
5715 client IP address) is passed to adaptation services.
5717 See also: follow_x_forwarded_for adaptation_send_client_ip
5721 IFDEF: USE_HTTP_VIOLATIONS
5725 LOC: Config.onoff.via
5727 If set (default), Squid will include a Via header in requests and
5728 replies as required by RFC2616.
5734 LOC: Config.onoff.ie_refresh
5737 Microsoft Internet Explorer up until version 5.5 Service
5738 Pack 1 has an issue with transparent proxies, wherein it
5739 is impossible to force a refresh. Turning this on provides
5740 a partial fix to the problem, by causing all IMS-REFRESH
5741 requests from older IE versions to check the origin server
5742 for fresh content. This reduces hit ratio by some amount
5743 (~10% in my experience), but allows users to actually get
5744 fresh content when they want it. Note because Squid
5745 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5746 of 5.5 is unchanged from old versions of Squid (i.e. a
5747 forced refresh is impossible). Newer versions of IE will,
5748 hopefully, continue to have the new behavior and will be
5749 handled based on that assumption. This option defaults to
5750 the old Squid behavior, which is better for hit ratios but
5751 worse for clients using IE, if they need to be able to
5752 force fresh content.
5755 NAME: vary_ignore_expire
5758 LOC: Config.onoff.vary_ignore_expire
5761 Many HTTP servers supporting Vary gives such objects
5762 immediate expiry time with no cache-control header
5763 when requested by a HTTP/1.0 client. This option
5764 enables Squid to ignore such expiry times until
5765 HTTP/1.1 is fully implemented.
5767 WARNING: If turned on this may eventually cause some
5768 varying objects not intended for caching to get cached.
5771 NAME: request_entities
5773 LOC: Config.onoff.request_entities
5776 Squid defaults to deny GET and HEAD requests with request entities,
5777 as the meaning of such requests are undefined in the HTTP standard
5778 even if not explicitly forbidden.
5780 Set this directive to on if you have clients which insists
5781 on sending request entities in GET or HEAD requests. But be warned
5782 that there is server software (both proxies and web servers) which
5783 can fail to properly process this kind of request which may make you
5784 vulnerable to cache pollution attacks if enabled.
5787 NAME: request_header_access
5788 IFDEF: USE_HTTP_VIOLATIONS
5789 TYPE: http_header_access
5790 LOC: Config.request_header_access
5792 DEFAULT_DOC: No limits.
5794 Usage: request_header_access header_name allow|deny [!]aclname ...
5796 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5797 this feature could make you liable for problems which it
5800 This option replaces the old 'anonymize_headers' and the
5801 older 'http_anonymizer' option with something that is much
5802 more configurable. A list of ACLs for each header name allows
5803 removal of specific header fields under specific conditions.
5805 This option only applies to outgoing HTTP request headers (i.e.,
5806 headers sent by Squid to the next HTTP hop such as a cache peer
5807 or an origin server). The option has no effect during cache hit
5808 detection. The equivalent adaptation vectoring point in ICAP
5809 terminology is post-cache REQMOD.
5811 The option is applied to individual outgoing request header
5812 fields. For each request header field F, Squid uses the first
5813 qualifying sets of request_header_access rules:
5815 1. Rules with header_name equal to F's name.
5816 2. Rules with header_name 'Other', provided F's name is not
5817 on the hard-coded list of commonly used HTTP header names.
5818 3. Rules with header_name 'All'.
5820 Within that qualifying rule set, rule ACLs are checked as usual.
5821 If ACLs of an "allow" rule match, the header field is allowed to
5822 go through as is. If ACLs of a "deny" rule match, the header is
5823 removed and request_header_replace is then checked to identify
5824 if the removed header has a replacement. If no rules within the
5825 set have matching ACLs, the header field is left as is.
5827 For example, to achieve the same behavior as the old
5828 'http_anonymizer standard' option, you should use:
5830 request_header_access From deny all
5831 request_header_access Referer deny all
5832 request_header_access User-Agent deny all
5834 Or, to reproduce the old 'http_anonymizer paranoid' feature
5837 request_header_access Authorization allow all
5838 request_header_access Proxy-Authorization allow all
5839 request_header_access Cache-Control allow all
5840 request_header_access Content-Length allow all
5841 request_header_access Content-Type allow all
5842 request_header_access Date allow all
5843 request_header_access Host allow all
5844 request_header_access If-Modified-Since allow all
5845 request_header_access Pragma allow all
5846 request_header_access Accept allow all
5847 request_header_access Accept-Charset allow all
5848 request_header_access Accept-Encoding allow all
5849 request_header_access Accept-Language allow all
5850 request_header_access Connection allow all
5851 request_header_access All deny all
5853 HTTP reply headers are controlled with the reply_header_access directive.
5855 By default, all headers are allowed (no anonymizing is performed).
5858 NAME: reply_header_access
5859 IFDEF: USE_HTTP_VIOLATIONS
5860 TYPE: http_header_access
5861 LOC: Config.reply_header_access
5863 DEFAULT_DOC: No limits.
5865 Usage: reply_header_access header_name allow|deny [!]aclname ...
5867 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5868 this feature could make you liable for problems which it
5871 This option only applies to reply headers, i.e., from the
5872 server to the client.
5874 This is the same as request_header_access, but in the other
5875 direction. Please see request_header_access for detailed
5878 For example, to achieve the same behavior as the old
5879 'http_anonymizer standard' option, you should use:
5881 reply_header_access Server deny all
5882 reply_header_access WWW-Authenticate deny all
5883 reply_header_access Link deny all
5885 Or, to reproduce the old 'http_anonymizer paranoid' feature
5888 reply_header_access Allow allow all
5889 reply_header_access WWW-Authenticate allow all
5890 reply_header_access Proxy-Authenticate allow all
5891 reply_header_access Cache-Control allow all
5892 reply_header_access Content-Encoding allow all
5893 reply_header_access Content-Length allow all
5894 reply_header_access Content-Type allow all
5895 reply_header_access Date allow all
5896 reply_header_access Expires allow all
5897 reply_header_access Last-Modified allow all
5898 reply_header_access Location allow all
5899 reply_header_access Pragma allow all
5900 reply_header_access Content-Language allow all
5901 reply_header_access Retry-After allow all
5902 reply_header_access Title allow all
5903 reply_header_access Content-Disposition allow all
5904 reply_header_access Connection allow all
5905 reply_header_access All deny all
5907 HTTP request headers are controlled with the request_header_access directive.
5909 By default, all headers are allowed (no anonymizing is
5913 NAME: request_header_replace header_replace
5914 IFDEF: USE_HTTP_VIOLATIONS
5915 TYPE: http_header_replace
5916 LOC: Config.request_header_access
5919 Usage: request_header_replace header_name message
5920 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
5922 This option allows you to change the contents of headers
5923 denied with request_header_access above, by replacing them
5924 with some fixed string.
5926 This only applies to request headers, not reply headers.
5928 By default, headers are removed if denied.
5931 NAME: reply_header_replace
5932 IFDEF: USE_HTTP_VIOLATIONS
5933 TYPE: http_header_replace
5934 LOC: Config.reply_header_access
5937 Usage: reply_header_replace header_name message
5938 Example: reply_header_replace Server Foo/1.0
5940 This option allows you to change the contents of headers
5941 denied with reply_header_access above, by replacing them
5942 with some fixed string.
5944 This only applies to reply headers, not request headers.
5946 By default, headers are removed if denied.
5949 NAME: request_header_add
5950 TYPE: HeaderWithAclList
5951 LOC: Config.request_header_add
5954 Usage: request_header_add field-name field-value acl1 [acl2] ...
5955 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
5957 This option adds header fields to outgoing HTTP requests (i.e.,
5958 request headers sent by Squid to the next HTTP hop such as a
5959 cache peer or an origin server). The option has no effect during
5960 cache hit detection. The equivalent adaptation vectoring point
5961 in ICAP terminology is post-cache REQMOD.
5963 Field-name is a token specifying an HTTP header name. If a
5964 standard HTTP header name is used, Squid does not check whether
5965 the new header conflicts with any existing headers or violates
5966 HTTP rules. If the request to be modified already contains a
5967 field with the same name, the old field is preserved but the
5968 header field values are not merged.
5970 Field-value is either a token or a quoted string. If quoted
5971 string format is used, then the surrounding quotes are removed
5972 while escape sequences and %macros are processed.
5974 In theory, all of the logformat codes can be used as %macros.
5975 However, unlike logging (which happens at the very end of
5976 transaction lifetime), the transaction may not yet have enough
5977 information to expand a macro when the new header value is needed.
5978 And some information may already be available to Squid but not yet
5979 committed where the macro expansion code can access it (report
5980 such instances!). The macro will be expanded into a single dash
5981 ('-') in such cases. Not all macros have been tested.
5983 One or more Squid ACLs may be specified to restrict header
5984 injection to matching requests. As always in squid.conf, all
5985 ACLs in an option ACL list must be satisfied for the insertion
5986 to happen. The request_header_add option supports fast ACLs
5995 This option used to log custom information about the master
5996 transaction. For example, an admin may configure Squid to log
5997 which "user group" the transaction belongs to, where "user group"
5998 will be determined based on a set of ACLs and not [just]
5999 authentication information.
6000 Values of key/value pairs can be logged using %{key}note macros:
6002 note key value acl ...
6003 logformat myFormat ... %{key}note ...
6006 NAME: relaxed_header_parser
6007 COMMENT: on|off|warn
6009 LOC: Config.onoff.relaxed_header_parser
6012 In the default "on" setting Squid accepts certain forms
6013 of non-compliant HTTP messages where it is unambiguous
6014 what the sending application intended even if the message
6015 is not correctly formatted. The messages is then normalized
6016 to the correct form when forwarded by Squid.
6018 If set to "warn" then a warning will be emitted in cache.log
6019 each time such HTTP error is encountered.
6021 If set to "off" then such HTTP errors will cause the request
6022 or response to be rejected.
6025 NAME: collapsed_forwarding
6028 LOC: Config.onoff.collapsed_forwarding
6031 This option controls whether Squid is allowed to merge multiple
6032 potentially cachable requests for the same URI before Squid knows
6033 whether the response is going to be cachable.
6035 This feature is disabled by default: Enabling collapsed forwarding
6036 needlessly delays forwarding requests that look cachable (when they are
6037 collapsed) but then need to be forwarded individually anyway because
6038 they end up being for uncachable content. However, in some cases, such
6039 as accelleration of highly cachable content with periodic or groupped
6040 expiration times, the gains from collapsing [large volumes of
6041 simultenous refresh requests] outweigh losses from such delays.
6046 -----------------------------------------------------------------------------
6049 NAME: forward_timeout
6052 LOC: Config.Timeout.forward
6055 This parameter specifies how long Squid should at most attempt in
6056 finding a forwarding path for the request before giving up.
6059 NAME: connect_timeout
6062 LOC: Config.Timeout.connect
6065 This parameter specifies how long to wait for the TCP connect to
6066 the requested server or peer to complete before Squid should
6067 attempt to find another path where to forward the request.
6070 NAME: peer_connect_timeout
6073 LOC: Config.Timeout.peer_connect
6076 This parameter specifies how long to wait for a pending TCP
6077 connection to a peer cache. The default is 30 seconds. You
6078 may also set different timeout values for individual neighbors
6079 with the 'connect-timeout' option on a 'cache_peer' line.
6085 LOC: Config.Timeout.read
6088 Applied on peer server connections.
6090 After each successful read(), the timeout will be extended by this
6091 amount. If no data is read again after this amount of time,
6092 the request is aborted and logged with ERR_READ_TIMEOUT.
6094 The default is 15 minutes.
6100 LOC: Config.Timeout.write
6103 This timeout is tracked for all connections that have data
6104 available for writing and are waiting for the socket to become
6105 ready. After each successful write, the timeout is extended by
6106 the configured amount. If Squid has data to write but the
6107 connection is not ready for the configured duration, the
6108 transaction associated with the connection is terminated. The
6109 default is 15 minutes.
6112 NAME: request_timeout
6114 LOC: Config.Timeout.request
6117 How long to wait for complete HTTP request headers after initial
6118 connection establishment.
6121 NAME: request_start_timeout
6123 LOC: Config.Timeout.request_start_timeout
6126 How long to wait for the first request byte after initial
6127 connection establishment.
6130 NAME: client_idle_pconn_timeout persistent_request_timeout
6132 LOC: Config.Timeout.clientIdlePconn
6135 How long to wait for the next HTTP request on a persistent
6136 client connection after the previous request completes.
6139 NAME: ftp_client_idle_timeout
6141 LOC: Config.Timeout.ftpClientIdle
6144 How long to wait for an FTP request on a connection to Squid ftp_port.
6145 Many FTP clients do not deal with idle connection closures well,
6146 necessitating a longer default timeout than client_idle_pconn_timeout
6147 used for incoming HTTP requests.
6150 NAME: client_lifetime
6153 LOC: Config.Timeout.lifetime
6156 The maximum amount of time a client (browser) is allowed to
6157 remain connected to the cache process. This protects the Cache
6158 from having a lot of sockets (and hence file descriptors) tied up
6159 in a CLOSE_WAIT state from remote clients that go away without
6160 properly shutting down (either because of a network failure or
6161 because of a poor client implementation). The default is one
6164 NOTE: The default value is intended to be much larger than any
6165 client would ever need to be connected to your cache. You
6166 should probably change client_lifetime only as a last resort.
6167 If you seem to have many client connections tying up
6168 filedescriptors, we recommend first tuning the read_timeout,
6169 request_timeout, persistent_request_timeout and quick_abort values.
6172 NAME: pconn_lifetime
6175 LOC: Config.Timeout.pconnLifetime
6178 Desired maximum lifetime of a persistent connection.
6179 When set, Squid will close a now-idle persistent connection that
6180 exceeded configured lifetime instead of moving the connection into
6181 the idle connection pool (or equivalent). No effect on ongoing/active
6182 transactions. Connection lifetime is the time period from the
6183 connection acceptance or opening time until "now".
6185 This limit is useful in environments with long-lived connections
6186 where Squid configuration or environmental factors change during a
6187 single connection lifetime. If unrestricted, some connections may
6188 last for hours and even days, ignoring those changes that should
6189 have affected their behavior or their existence.
6191 Currently, a new lifetime value supplied via Squid reconfiguration
6192 has no effect on already idle connections unless they become busy.
6194 When set to '0' this limit is not used.
6197 NAME: half_closed_clients
6199 LOC: Config.onoff.half_closed_clients
6202 Some clients may shutdown the sending side of their TCP
6203 connections, while leaving their receiving sides open. Sometimes,
6204 Squid can not tell the difference between a half-closed and a
6205 fully-closed TCP connection.
6207 By default, Squid will immediately close client connections when
6208 read(2) returns "no more data to read."
6210 Change this option to 'on' and Squid will keep open connections
6211 until a read(2) or write(2) on the socket returns an error.
6212 This may show some benefits for reverse proxies. But if not
6213 it is recommended to leave OFF.
6216 NAME: server_idle_pconn_timeout pconn_timeout
6218 LOC: Config.Timeout.serverIdlePconn
6221 Timeout for idle persistent connections to servers and other
6228 LOC: Ident::TheConfig.timeout
6231 Maximum time to wait for IDENT lookups to complete.
6233 If this is too high, and you enabled IDENT lookups from untrusted
6234 users, you might be susceptible to denial-of-service by having
6235 many ident requests going at once.
6238 NAME: shutdown_lifetime
6241 LOC: Config.shutdownLifetime
6244 When SIGTERM or SIGHUP is received, the cache is put into
6245 "shutdown pending" mode until all active sockets are closed.
6246 This value is the lifetime to set for all open descriptors
6247 during shutdown mode. Any active clients after this many
6248 seconds will receive a 'timeout' message.
6252 ADMINISTRATIVE PARAMETERS
6253 -----------------------------------------------------------------------------
6259 LOC: Config.adminEmail
6261 Email-address of local cache manager who will receive
6262 mail if the cache dies. The default is "webmaster".
6268 LOC: Config.EmailFrom
6270 From: email-address for mail sent when the cache dies.
6271 The default is to use 'squid@unique_hostname'.
6273 See also: unique_hostname directive.
6279 LOC: Config.EmailProgram
6281 Email program used to send mail if the cache dies.
6282 The default is "mail". The specified program must comply
6283 with the standard Unix mail syntax:
6284 mail-program recipient < mailfile
6286 Optional command line options can be specified.
6289 NAME: cache_effective_user
6291 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
6292 LOC: Config.effectiveUser
6294 If you start Squid as root, it will change its effective/real
6295 UID/GID to the user specified below. The default is to change
6296 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
6297 see also; cache_effective_group
6300 NAME: cache_effective_group
6303 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
6304 LOC: Config.effectiveGroup
6306 Squid sets the GID to the effective user's default group ID
6307 (taken from the password file) and supplementary group list
6308 from the groups membership.
6310 If you want Squid to run with a specific GID regardless of
6311 the group memberships of the effective user then set this
6312 to the group (or GID) you want Squid to run as. When set
6313 all other group privileges of the effective user are ignored
6314 and only this GID is effective. If Squid is not started as
6315 root the user starting Squid MUST be member of the specified
6318 This option is not recommended by the Squid Team.
6319 Our preference is for administrators to configure a secure
6320 user account for squid with UID/GID matching system policies.
6323 NAME: httpd_suppress_version_string
6327 LOC: Config.onoff.httpd_suppress_version_string
6329 Suppress Squid version string info in HTTP headers and HTML error pages.
6332 NAME: visible_hostname
6334 LOC: Config.visibleHostname
6336 DEFAULT_DOC: Automatically detect the system host name
6338 If you want to present a special hostname in error messages, etc,
6339 define this. Otherwise, the return value of gethostname()
6340 will be used. If you have multiple caches in a cluster and
6341 get errors about IP-forwarding you must set them to have individual
6342 names with this setting.
6345 NAME: unique_hostname
6347 LOC: Config.uniqueHostname
6349 DEFAULT_DOC: Copy the value from visible_hostname
6351 If you want to have multiple machines with the same
6352 'visible_hostname' you must give each machine a different
6353 'unique_hostname' so forwarding loops can be detected.
6356 NAME: hostname_aliases
6358 LOC: Config.hostnameAliases
6361 A list of other DNS names your cache has.
6369 Minimum umask which should be enforced while the proxy
6370 is running, in addition to the umask set at startup.
6372 For a traditional octal representation of umasks, start
6377 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6378 -----------------------------------------------------------------------------
6380 This section contains parameters for the (optional) cache
6381 announcement service. This service is provided to help
6382 cache administrators locate one another in order to join or
6383 create cache hierarchies.
6385 An 'announcement' message is sent (via UDP) to the registration
6386 service by Squid. By default, the announcement message is NOT
6387 SENT unless you enable it with 'announce_period' below.
6389 The announcement message includes your hostname, plus the
6390 following information from this configuration file:
6396 All current information is processed regularly and made
6397 available on the Web at http://www.ircache.net/Cache/Tracker/.
6400 NAME: announce_period
6402 LOC: Config.Announce.period
6404 DEFAULT_DOC: Announcement messages disabled.
6406 This is how frequently to send cache announcements.
6408 To enable announcing your cache, just set an announce period.
6411 announce_period 1 day
6416 DEFAULT: tracker.ircache.net
6417 LOC: Config.Announce.host
6419 Set the hostname where announce registration messages will be sent.
6421 See also announce_port and announce_file
6427 LOC: Config.Announce.file
6429 The contents of this file will be included in the announce
6430 registration messages.
6436 LOC: Config.Announce.port
6438 Set the port where announce registration messages will be sent.
6440 See also announce_host and announce_file
6444 HTTPD-ACCELERATOR OPTIONS
6445 -----------------------------------------------------------------------------
6448 NAME: httpd_accel_surrogate_id
6451 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
6452 LOC: Config.Accel.surrogate_id
6454 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
6455 need an identification token to allow control targeting. Because
6456 a farm of surrogates may all perform the same tasks, they may share
6457 an identification token.
6460 NAME: http_accel_surrogate_remote
6464 LOC: Config.onoff.surrogate_is_remote
6466 Remote surrogates (such as those in a CDN) honour the header
6467 "Surrogate-Control: no-store-remote".
6469 Set this to on to have squid behave as a remote surrogate.
6473 IFDEF: USE_SQUID_ESI
6474 COMMENT: libxml2|expat|custom
6476 LOC: ESIParser::Type
6479 ESI markup is not strictly XML compatible. The custom ESI parser
6480 will give higher performance, but cannot handle non ASCII character
6485 DELAY POOL PARAMETERS
6486 -----------------------------------------------------------------------------
6490 TYPE: delay_pool_count
6492 IFDEF: USE_DELAY_POOLS
6495 This represents the number of delay pools to be used. For example,
6496 if you have one class 2 delay pool and one class 3 delays pool, you
6497 have a total of 2 delay pools.
6499 See also delay_parameters, delay_class, delay_access for pool
6500 configuration details.
6504 TYPE: delay_pool_class
6506 IFDEF: USE_DELAY_POOLS
6509 This defines the class of each delay pool. There must be exactly one
6510 delay_class line for each delay pool. For example, to define two
6511 delay pools, one of class 2 and one of class 3, the settings above
6515 delay_pools 4 # 4 delay pools
6516 delay_class 1 2 # pool 1 is a class 2 pool
6517 delay_class 2 3 # pool 2 is a class 3 pool
6518 delay_class 3 4 # pool 3 is a class 4 pool
6519 delay_class 4 5 # pool 4 is a class 5 pool
6521 The delay pool classes are:
6523 class 1 Everything is limited by a single aggregate
6526 class 2 Everything is limited by a single aggregate
6527 bucket as well as an "individual" bucket chosen
6528 from bits 25 through 32 of the IPv4 address.
6530 class 3 Everything is limited by a single aggregate
6531 bucket as well as a "network" bucket chosen
6532 from bits 17 through 24 of the IP address and a
6533 "individual" bucket chosen from bits 17 through
6534 32 of the IPv4 address.
6536 class 4 Everything in a class 3 delay pool, with an
6537 additional limit on a per user basis. This
6538 only takes effect if the username is established
6539 in advance - by forcing authentication in your
6542 class 5 Requests are grouped according their tag (see
6543 external_acl's tag= reply).
6546 Each pool also requires a delay_parameters directive to configure the pool size
6547 and speed limits used whenever the pool is applied to a request. Along with
6548 a set of delay_access directives to determine when it is used.
6550 NOTE: If an IP address is a.b.c.d
6551 -> bits 25 through 32 are "d"
6552 -> bits 17 through 24 are "c"
6553 -> bits 17 through 32 are "c * 256 + d"
6555 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6556 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6558 This clause only supports fast acl types.
6559 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6561 See also delay_parameters and delay_access.
6565 TYPE: delay_pool_access
6567 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6568 IFDEF: USE_DELAY_POOLS
6571 This is used to determine which delay pool a request falls into.
6573 delay_access is sorted per pool and the matching starts with pool 1,
6574 then pool 2, ..., and finally pool N. The first delay pool where the
6575 request is allowed is selected for the request. If it does not allow
6576 the request to any pool then the request is not delayed (default).
6578 For example, if you want some_big_clients in delay
6579 pool 1 and lotsa_little_clients in delay pool 2:
6581 delay_access 1 allow some_big_clients
6582 delay_access 1 deny all
6583 delay_access 2 allow lotsa_little_clients
6584 delay_access 2 deny all
6585 delay_access 3 allow authenticated_clients
6587 See also delay_parameters and delay_class.
6591 NAME: delay_parameters
6592 TYPE: delay_pool_rates
6594 IFDEF: USE_DELAY_POOLS
6597 This defines the parameters for a delay pool. Each delay pool has
6598 a number of "buckets" associated with it, as explained in the
6599 description of delay_class.
6601 For a class 1 delay pool, the syntax is:
6603 delay_parameters pool aggregate
6605 For a class 2 delay pool:
6607 delay_parameters pool aggregate individual
6609 For a class 3 delay pool:
6611 delay_parameters pool aggregate network individual
6613 For a class 4 delay pool:
6615 delay_parameters pool aggregate network individual user
6617 For a class 5 delay pool:
6619 delay_parameters pool tagrate
6621 The option variables are:
6623 pool a pool number - ie, a number between 1 and the
6624 number specified in delay_pools as used in
6627 aggregate the speed limit parameters for the aggregate bucket
6630 individual the speed limit parameters for the individual
6631 buckets (class 2, 3).
6633 network the speed limit parameters for the network buckets
6636 user the speed limit parameters for the user buckets
6639 tagrate the speed limit parameters for the tag buckets
6642 A pair of delay parameters is written restore/maximum, where restore is
6643 the number of bytes (not bits - modem and network speeds are usually
6644 quoted in bits) per second placed into the bucket, and maximum is the
6645 maximum number of bytes which can be in the bucket at any time.
6647 There must be one delay_parameters line for each delay pool.
6650 For example, if delay pool number 1 is a class 2 delay pool as in the
6651 above example, and is being used to strictly limit each host to 64Kbit/sec
6652 (plus overheads), with no overall limit, the line is:
6654 delay_parameters 1 none 8000/8000
6656 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
6658 Note that the word 'none' is used to represent no limit.
6661 And, if delay pool number 2 is a class 3 delay pool as in the above
6662 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6663 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6664 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6665 to permit a decent web page to be downloaded at a decent speed
6666 (if the network is not being limited due to overuse) but slow down
6667 large downloads more significantly:
6669 delay_parameters 2 32000/32000 8000/8000 600/8000
6671 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
6672 8 x 8000 KByte/sec -> 64Kbit/sec.
6673 8 x 600 Byte/sec -> 4800bit/sec.
6676 Finally, for a class 4 delay pool as in the example - each user will
6677 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6679 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6682 See also delay_class and delay_access.
6686 NAME: delay_initial_bucket_level
6687 COMMENT: (percent, 0-100)
6690 IFDEF: USE_DELAY_POOLS
6691 LOC: Config.Delay.initial
6693 The initial bucket percentage is used to determine how much is put
6694 in each bucket when squid starts, is reconfigured, or first notices
6695 a host accessing it (in class 2 and class 3, individual hosts and
6696 networks only have buckets associated with them once they have been
6701 CLIENT DELAY POOL PARAMETERS
6702 -----------------------------------------------------------------------------
6705 NAME: client_delay_pools
6706 TYPE: client_delay_pool_count
6708 IFDEF: USE_DELAY_POOLS
6709 LOC: Config.ClientDelay
6711 This option specifies the number of client delay pools used. It must
6712 preceed other client_delay_* options.
6715 client_delay_pools 2
6717 See also client_delay_parameters and client_delay_access.
6720 NAME: client_delay_initial_bucket_level
6721 COMMENT: (percent, 0-no_limit)
6724 IFDEF: USE_DELAY_POOLS
6725 LOC: Config.ClientDelay.initial
6727 This option determines the initial bucket size as a percentage of
6728 max_bucket_size from client_delay_parameters. Buckets are created
6729 at the time of the "first" connection from the matching IP. Idle
6730 buckets are periodically deleted up.
6732 You can specify more than 100 percent but note that such "oversized"
6733 buckets are not refilled until their size goes down to max_bucket_size
6734 from client_delay_parameters.
6737 client_delay_initial_bucket_level 50
6740 NAME: client_delay_parameters
6741 TYPE: client_delay_pool_rates
6743 IFDEF: USE_DELAY_POOLS
6744 LOC: Config.ClientDelay
6747 This option configures client-side bandwidth limits using the
6750 client_delay_parameters pool speed_limit max_bucket_size
6752 pool is an integer ID used for client_delay_access matching.
6754 speed_limit is bytes added to the bucket per second.
6756 max_bucket_size is the maximum size of a bucket, enforced after any
6757 speed_limit additions.
6759 Please see the delay_parameters option for more information and
6763 client_delay_parameters 1 1024 2048
6764 client_delay_parameters 2 51200 16384
6766 See also client_delay_access.
6770 NAME: client_delay_access
6771 TYPE: client_delay_pool_access
6773 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6774 IFDEF: USE_DELAY_POOLS
6775 LOC: Config.ClientDelay
6777 This option determines the client-side delay pool for the
6780 client_delay_access pool_ID allow|deny acl_name
6782 All client_delay_access options are checked in their pool ID
6783 order, starting with pool 1. The first checked pool with allowed
6784 request is selected for the request. If no ACL matches or there
6785 are no client_delay_access options, the request bandwidth is not
6788 The ACL-selected pool is then used to find the
6789 client_delay_parameters for the request. Client-side pools are
6790 not used to aggregate clients. Clients are always aggregated
6791 based on their source IP addresses (one bucket per source IP).
6793 This clause only supports fast acl types.
6794 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6795 Additionally, only the client TCP connection details are available.
6796 ACLs testing HTTP properties will not work.
6798 Please see delay_access for more examples.
6801 client_delay_access 1 allow low_rate_network
6802 client_delay_access 2 allow vips_network
6805 See also client_delay_parameters and client_delay_pools.
6809 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6810 -----------------------------------------------------------------------------
6815 LOC: Config.Wccp.router
6817 DEFAULT_DOC: WCCP disabled.
6820 Use this option to define your WCCP ``home'' router for
6823 wccp_router supports a single WCCP(v1) router
6825 wccp2_router supports multiple WCCPv2 routers
6827 only one of the two may be used at the same time and defines
6828 which version of WCCP to use.
6832 TYPE: IpAddress_list
6833 LOC: Config.Wccp2.router
6835 DEFAULT_DOC: WCCPv2 disabled.
6838 Use this option to define your WCCP ``home'' router for
6841 wccp_router supports a single WCCP(v1) router
6843 wccp2_router supports multiple WCCPv2 routers
6845 only one of the two may be used at the same time and defines
6846 which version of WCCP to use.
6851 LOC: Config.Wccp.version
6855 This directive is only relevant if you need to set up WCCP(v1)
6856 to some very old and end-of-life Cisco routers. In all other
6857 setups it must be left unset or at the default setting.
6858 It defines an internal version in the WCCP(v1) protocol,
6859 with version 4 being the officially documented protocol.
6861 According to some users, Cisco IOS 11.2 and earlier only
6862 support WCCP version 3. If you're using that or an earlier
6863 version of IOS, you may need to change this value to 3, otherwise
6864 do not specify this parameter.
6867 NAME: wccp2_rebuild_wait
6869 LOC: Config.Wccp2.rebuildwait
6873 If this is enabled Squid will wait for the cache dir rebuild to finish
6874 before sending the first wccp2 HereIAm packet
6877 NAME: wccp2_forwarding_method
6879 LOC: Config.Wccp2.forwarding_method
6883 WCCP2 allows the setting of forwarding methods between the
6884 router/switch and the cache. Valid values are as follows:
6886 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6887 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6889 Currently (as of IOS 12.4) cisco routers only support GRE.
6890 Cisco switches only support the L2 redirect assignment method.
6893 NAME: wccp2_return_method
6895 LOC: Config.Wccp2.return_method
6899 WCCP2 allows the setting of return methods between the
6900 router/switch and the cache for packets that the cache
6901 decides not to handle. Valid values are as follows:
6903 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6904 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6906 Currently (as of IOS 12.4) cisco routers only support GRE.
6907 Cisco switches only support the L2 redirect assignment.
6909 If the "ip wccp redirect exclude in" command has been
6910 enabled on the cache interface, then it is still safe for
6911 the proxy server to use a l2 redirect method even if this
6912 option is set to GRE.
6915 NAME: wccp2_assignment_method
6917 LOC: Config.Wccp2.assignment_method
6921 WCCP2 allows the setting of methods to assign the WCCP hash
6922 Valid values are as follows:
6924 hash - Hash assignment
6925 mask - Mask assignment
6927 As a general rule, cisco routers support the hash assignment method
6928 and cisco switches support the mask assignment method.
6933 LOC: Config.Wccp2.info
6934 DEFAULT_IF_NONE: standard 0
6935 DEFAULT_DOC: Use the 'web-cache' standard service.
6938 WCCP2 allows for multiple traffic services. There are two
6939 types: "standard" and "dynamic". The standard type defines
6940 one service id - http (id 0). The dynamic service ids can be from
6941 51 to 255 inclusive. In order to use a dynamic service id
6942 one must define the type of traffic to be redirected; this is done
6943 using the wccp2_service_info option.
6945 The "standard" type does not require a wccp2_service_info option,
6946 just specifying the service id will suffice.
6948 MD5 service authentication can be enabled by adding
6949 "password=<password>" to the end of this service declaration.
6953 wccp2_service standard 0 # for the 'web-cache' standard service
6954 wccp2_service dynamic 80 # a dynamic service type which will be
6955 # fleshed out with subsequent options.
6956 wccp2_service standard 0 password=foo
6959 NAME: wccp2_service_info
6960 TYPE: wccp2_service_info
6961 LOC: Config.Wccp2.info
6965 Dynamic WCCPv2 services require further information to define the
6966 traffic you wish to have diverted.
6970 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
6971 priority=<priority> ports=<port>,<port>..
6973 The relevant WCCPv2 flags:
6974 + src_ip_hash, dst_ip_hash
6975 + source_port_hash, dst_port_hash
6976 + src_ip_alt_hash, dst_ip_alt_hash
6977 + src_port_alt_hash, dst_port_alt_hash
6980 The port list can be one to eight entries.
6984 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
6985 priority=240 ports=80
6987 Note: the service id must have been defined by a previous
6988 'wccp2_service dynamic <id>' entry.
6993 LOC: Config.Wccp2.weight
6997 Each cache server gets assigned a set of the destination
6998 hash proportional to their weight.
7003 LOC: Config.Wccp.address
7005 DEFAULT_DOC: Address selected by the operating system.
7008 Use this option if you require WCCPv2 to use a specific
7011 The default behavior is to not bind to any specific address.
7016 LOC: Config.Wccp2.address
7018 DEFAULT_DOC: Address selected by the operating system.
7021 Use this option if you require WCCP to use a specific
7024 The default behavior is to not bind to any specific address.
7028 PERSISTENT CONNECTION HANDLING
7029 -----------------------------------------------------------------------------
7031 Also see "pconn_timeout" in the TIMEOUTS section
7034 NAME: client_persistent_connections
7036 LOC: Config.onoff.client_pconns
7039 Persistent connection support for clients.
7040 Squid uses persistent connections (when allowed). You can use
7041 this option to disable persistent connections with clients.
7044 NAME: server_persistent_connections
7046 LOC: Config.onoff.server_pconns
7049 Persistent connection support for servers.
7050 Squid uses persistent connections (when allowed). You can use
7051 this option to disable persistent connections with servers.
7054 NAME: persistent_connection_after_error
7056 LOC: Config.onoff.error_pconns
7059 With this directive the use of persistent connections after
7060 HTTP errors can be disabled. Useful if you have clients
7061 who fail to handle errors on persistent connections proper.
7064 NAME: detect_broken_pconn
7066 LOC: Config.onoff.detect_broken_server_pconns
7069 Some servers have been found to incorrectly signal the use
7070 of HTTP/1.0 persistent connections even on replies not
7071 compatible, causing significant delays. This server problem
7072 has mostly been seen on redirects.
7074 By enabling this directive Squid attempts to detect such
7075 broken replies and automatically assume the reply is finished
7076 after 10 seconds timeout.
7080 CACHE DIGEST OPTIONS
7081 -----------------------------------------------------------------------------
7084 NAME: digest_generation
7085 IFDEF: USE_CACHE_DIGESTS
7087 LOC: Config.onoff.digest_generation
7090 This controls whether the server will generate a Cache Digest
7091 of its contents. By default, Cache Digest generation is
7092 enabled if Squid is compiled with --enable-cache-digests defined.
7095 NAME: digest_bits_per_entry
7096 IFDEF: USE_CACHE_DIGESTS
7098 LOC: Config.digest.bits_per_entry
7101 This is the number of bits of the server's Cache Digest which
7102 will be associated with the Digest entry for a given HTTP
7103 Method and URL (public key) combination. The default is 5.
7106 NAME: digest_rebuild_period
7107 IFDEF: USE_CACHE_DIGESTS
7110 LOC: Config.digest.rebuild_period
7113 This is the wait time between Cache Digest rebuilds.
7116 NAME: digest_rewrite_period
7118 IFDEF: USE_CACHE_DIGESTS
7120 LOC: Config.digest.rewrite_period
7123 This is the wait time between Cache Digest writes to
7127 NAME: digest_swapout_chunk_size
7130 IFDEF: USE_CACHE_DIGESTS
7131 LOC: Config.digest.swapout_chunk_size
7134 This is the number of bytes of the Cache Digest to write to
7135 disk at a time. It defaults to 4096 bytes (4KB), the Squid
7139 NAME: digest_rebuild_chunk_percentage
7140 COMMENT: (percent, 0-100)
7141 IFDEF: USE_CACHE_DIGESTS
7143 LOC: Config.digest.rebuild_chunk_percentage
7146 This is the percentage of the Cache Digest to be scanned at a
7147 time. By default it is set to 10% of the Cache Digest.
7152 -----------------------------------------------------------------------------
7157 LOC: Config.Port.snmp
7159 DEFAULT_DOC: SNMP disabled.
7162 The port number where Squid listens for SNMP requests. To enable
7163 SNMP support set this to a suitable port number. Port number
7164 3401 is often used for the Squid SNMP agent. By default it's
7165 set to "0" (disabled)
7173 LOC: Config.accessList.snmp
7175 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
7178 Allowing or denying access to the SNMP port.
7180 All access to the agent is denied by default.
7183 snmp_access allow|deny [!]aclname ...
7185 This clause only supports fast acl types.
7186 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7189 snmp_access allow snmppublic localhost
7190 snmp_access deny all
7193 NAME: snmp_incoming_address
7195 LOC: Config.Addrs.snmp_incoming
7197 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
7200 Just like 'udp_incoming_address', but for the SNMP port.
7202 snmp_incoming_address is used for the SNMP socket receiving
7203 messages from SNMP agents.
7205 The default snmp_incoming_address is to listen on all
7206 available network interfaces.
7209 NAME: snmp_outgoing_address
7211 LOC: Config.Addrs.snmp_outgoing
7213 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
7216 Just like 'udp_outgoing_address', but for the SNMP port.
7218 snmp_outgoing_address is used for SNMP packets returned to SNMP
7221 If snmp_outgoing_address is not set it will use the same socket
7222 as snmp_incoming_address. Only change this if you want to have
7223 SNMP replies sent using another address than where this Squid
7224 listens for SNMP queries.
7226 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
7227 the same value since they both use the same port.
7232 -----------------------------------------------------------------------------
7235 NAME: icp_port udp_port
7238 DEFAULT_DOC: ICP disabled.
7239 LOC: Config.Port.icp
7241 The port number where Squid sends and receives ICP queries to
7242 and from neighbor caches. The standard UDP port for ICP is 3130.
7245 icp_port @DEFAULT_ICP_PORT@
7252 DEFAULT_DOC: HTCP disabled.
7253 LOC: Config.Port.htcp
7255 The port number where Squid sends and receives HTCP queries to
7256 and from neighbor caches. To turn it on you want to set it to
7263 NAME: log_icp_queries
7267 LOC: Config.onoff.log_udp
7269 If set, ICP queries are logged to access.log. You may wish
7270 do disable this if your ICP load is VERY high to speed things
7271 up or to simplify log analysis.
7274 NAME: udp_incoming_address
7276 LOC:Config.Addrs.udp_incoming
7278 DEFAULT_DOC: Accept packets from all machine interfaces.
7280 udp_incoming_address is used for UDP packets received from other
7283 The default behavior is to not bind to any specific address.
7285 Only change this if you want to have all UDP queries received on
7286 a specific interface/address.
7288 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
7289 modules. Altering it will affect all of them in the same manner.
7291 see also; udp_outgoing_address
7293 NOTE, udp_incoming_address and udp_outgoing_address can not
7294 have the same value since they both use the same port.
7297 NAME: udp_outgoing_address
7299 LOC: Config.Addrs.udp_outgoing
7301 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
7303 udp_outgoing_address is used for UDP packets sent out to other
7306 The default behavior is to not bind to any specific address.
7308 Instead it will use the same socket as udp_incoming_address.
7309 Only change this if you want to have UDP queries sent using another
7310 address than where this Squid listens for UDP queries from other
7313 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7314 modules. Altering it will affect all of them in the same manner.
7316 see also; udp_incoming_address
7318 NOTE, udp_incoming_address and udp_outgoing_address can not
7319 have the same value since they both use the same port.
7326 LOC: Config.onoff.icp_hit_stale
7328 If you want to return ICP_HIT for stale cache objects, set this
7329 option to 'on'. If you have sibling relationships with caches
7330 in other administrative domains, this should be 'off'. If you only
7331 have sibling relationships with caches under your control,
7332 it is probably okay to set this to 'on'.
7333 If set to 'on', your siblings should use the option "allow-miss"
7334 on their cache_peer lines for connecting to you.
7337 NAME: minimum_direct_hops
7340 LOC: Config.minDirectHops
7342 If using the ICMP pinging stuff, do direct fetches for sites
7343 which are no more than this many hops away.
7346 NAME: minimum_direct_rtt
7350 LOC: Config.minDirectRtt
7352 If using the ICMP pinging stuff, do direct fetches for sites
7353 which are no more than this many rtt milliseconds away.
7359 LOC: Config.Netdb.low
7361 The low water mark for the ICMP measurement database.
7363 Note: high watermark controlled by netdb_high directive.
7365 These watermarks are counts, not percents. The defaults are
7366 (low) 900 and (high) 1000. When the high water mark is
7367 reached, database entries will be deleted until the low
7374 LOC: Config.Netdb.high
7376 The high water mark for the ICMP measurement database.
7378 Note: low watermark controlled by netdb_low directive.
7380 These watermarks are counts, not percents. The defaults are
7381 (low) 900 and (high) 1000. When the high water mark is
7382 reached, database entries will be deleted until the low
7386 NAME: netdb_ping_period
7388 LOC: Config.Netdb.period
7391 The minimum period for measuring a site. There will be at
7392 least this much delay between successive pings to the same
7393 network. The default is five minutes.
7400 LOC: Config.onoff.query_icmp
7402 If you want to ask your peers to include ICMP data in their ICP
7403 replies, enable this option.
7405 If your peer has configured Squid (during compilation) with
7406 '--enable-icmp' that peer will send ICMP pings to origin server
7407 sites of the URLs it receives. If you enable this option the
7408 ICP replies from that peer will include the ICMP data (if available).
7409 Then, when choosing a parent cache, Squid will choose the parent with
7410 the minimal RTT to the origin server. When this happens, the
7411 hierarchy field of the access.log will be
7412 "CLOSEST_PARENT_MISS". This option is off by default.
7415 NAME: test_reachability
7419 LOC: Config.onoff.test_reachability
7421 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
7422 instead of ICP_MISS if the target host is NOT in the ICMP
7423 database, or has a zero RTT.
7426 NAME: icp_query_timeout
7429 DEFAULT_DOC: Dynamic detection.
7431 LOC: Config.Timeout.icp_query
7433 Normally Squid will automatically determine an optimal ICP
7434 query timeout value based on the round-trip-time of recent ICP
7435 queries. If you want to override the value determined by
7436 Squid, set this 'icp_query_timeout' to a non-zero value. This
7437 value is specified in MILLISECONDS, so, to use a 2-second
7438 timeout (the old default), you would write:
7440 icp_query_timeout 2000
7443 NAME: maximum_icp_query_timeout
7447 LOC: Config.Timeout.icp_query_max
7449 Normally the ICP query timeout is determined dynamically. But
7450 sometimes it can lead to very large values (say 5 seconds).
7451 Use this option to put an upper limit on the dynamic timeout
7452 value. Do NOT use this option to always use a fixed (instead
7453 of a dynamic) timeout value. To set a fixed timeout see the
7454 'icp_query_timeout' directive.
7457 NAME: minimum_icp_query_timeout
7461 LOC: Config.Timeout.icp_query_min
7463 Normally the ICP query timeout is determined dynamically. But
7464 sometimes it can lead to very small timeouts, even lower than
7465 the normal latency variance on your link due to traffic.
7466 Use this option to put an lower limit on the dynamic timeout
7467 value. Do NOT use this option to always use a fixed (instead
7468 of a dynamic) timeout value. To set a fixed timeout see the
7469 'icp_query_timeout' directive.
7472 NAME: background_ping_rate
7476 LOC: Config.backgroundPingRate
7478 Controls how often the ICP pings are sent to siblings that
7479 have background-ping set.
7483 MULTICAST ICP OPTIONS
7484 -----------------------------------------------------------------------------
7489 LOC: Config.mcast_group_list
7492 This tag specifies a list of multicast groups which your server
7493 should join to receive multicasted ICP queries.
7495 NOTE! Be very careful what you put here! Be sure you
7496 understand the difference between an ICP _query_ and an ICP
7497 _reply_. This option is to be set only if you want to RECEIVE
7498 multicast queries. Do NOT set this option to SEND multicast
7499 ICP (use cache_peer for that). ICP replies are always sent via
7500 unicast, so this option does not affect whether or not you will
7501 receive replies from multicast group members.
7503 You must be very careful to NOT use a multicast address which
7504 is already in use by another group of caches.
7506 If you are unsure about multicast, please read the Multicast
7507 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7509 Usage: mcast_groups 239.128.16.128 224.0.1.20
7511 By default, Squid doesn't listen on any multicast groups.
7514 NAME: mcast_miss_addr
7515 IFDEF: MULTICAST_MISS_STREAM
7517 LOC: Config.mcast_miss.addr
7519 DEFAULT_DOC: disabled.
7521 If you enable this option, every "cache miss" URL will
7522 be sent out on the specified multicast address.
7524 Do not enable this option unless you are are absolutely
7525 certain you understand what you are doing.
7528 NAME: mcast_miss_ttl
7529 IFDEF: MULTICAST_MISS_STREAM
7531 LOC: Config.mcast_miss.ttl
7534 This is the time-to-live value for packets multicasted
7535 when multicasting off cache miss URLs is enabled. By
7536 default this is set to 'site scope', i.e. 16.
7539 NAME: mcast_miss_port
7540 IFDEF: MULTICAST_MISS_STREAM
7542 LOC: Config.mcast_miss.port
7545 This is the port number to be used in conjunction with
7549 NAME: mcast_miss_encode_key
7550 IFDEF: MULTICAST_MISS_STREAM
7552 LOC: Config.mcast_miss.encode_key
7553 DEFAULT: XXXXXXXXXXXXXXXX
7555 The URLs that are sent in the multicast miss stream are
7556 encrypted. This is the encryption key.
7559 NAME: mcast_icp_query_timeout
7563 LOC: Config.Timeout.mcast_icp_query
7565 For multicast peers, Squid regularly sends out ICP "probes" to
7566 count how many other peers are listening on the given multicast
7567 address. This value specifies how long Squid should wait to
7568 count all the replies. The default is 2000 msec, or 2
7573 INTERNAL ICON OPTIONS
7574 -----------------------------------------------------------------------------
7577 NAME: icon_directory
7579 LOC: Config.icons.directory
7580 DEFAULT: @DEFAULT_ICON_DIR@
7582 Where the icons are stored. These are normally kept in
7586 NAME: global_internal_static
7588 LOC: Config.onoff.global_internal_static
7591 This directive controls is Squid should intercept all requests for
7592 /squid-internal-static/ no matter which host the URL is requesting
7593 (default on setting), or if nothing special should be done for
7594 such URLs (off setting). The purpose of this directive is to make
7595 icons etc work better in complex cache hierarchies where it may
7596 not always be possible for all corners in the cache mesh to reach
7597 the server generating a directory listing.
7600 NAME: short_icon_urls
7602 LOC: Config.icons.use_short_names
7605 If this is enabled Squid will use short URLs for icons.
7606 If disabled it will revert to the old behavior of including
7607 it's own name and port in the URL.
7609 If you run a complex cache hierarchy with a mix of Squid and
7610 other proxies you may need to disable this directive.
7615 -----------------------------------------------------------------------------
7618 NAME: error_directory
7620 LOC: Config.errorDirectory
7622 DEFAULT_DOC: Send error pages in the clients preferred language
7624 If you wish to create your own versions of the default
7625 error files to customize them to suit your company copy
7626 the error/template files to another directory and point
7629 WARNING: This option will disable multi-language support
7630 on error pages if used.
7632 The squid developers are interested in making squid available in
7633 a wide variety of languages. If you are making translations for a
7634 language that Squid does not currently provide please consider
7635 contributing your translation back to the project.
7636 http://wiki.squid-cache.org/Translations
7638 The squid developers working on translations are happy to supply drop-in
7639 translated error files in exchange for any new language contributions.
7642 NAME: error_default_language
7643 IFDEF: USE_ERR_LOCALES
7645 LOC: Config.errorDefaultLanguage
7647 DEFAULT_DOC: Generate English language pages.
7649 Set the default language which squid will send error pages in
7650 if no existing translation matches the clients language
7653 If unset (default) generic English will be used.
7655 The squid developers are interested in making squid available in
7656 a wide variety of languages. If you are interested in making
7657 translations for any language see the squid wiki for details.
7658 http://wiki.squid-cache.org/Translations
7661 NAME: error_log_languages
7662 IFDEF: USE_ERR_LOCALES
7664 LOC: Config.errorLogMissingLanguages
7667 Log to cache.log what languages users are attempting to
7668 auto-negotiate for translations.
7670 Successful negotiations are not logged. Only failures
7671 have meaning to indicate that Squid may need an upgrade
7672 of its error page translations.
7675 NAME: err_page_stylesheet
7677 LOC: Config.errorStylesheet
7678 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7680 CSS Stylesheet to pattern the display of Squid default error pages.
7682 For information on CSS see http://www.w3.org/Style/CSS/
7687 LOC: Config.errHtmlText
7690 HTML text to include in error messages. Make this a "mailto"
7691 URL to your admin address, or maybe just a link to your
7692 organizations Web page.
7694 To include this in your error messages, you must rewrite
7695 the error template files (found in the "errors" directory).
7696 Wherever you want the 'err_html_text' line to appear,
7697 insert a %L tag in the error template file.
7700 NAME: email_err_data
7703 LOC: Config.onoff.emailErrData
7706 If enabled, information about the occurred error will be
7707 included in the mailto links of the ERR pages (if %W is set)
7708 so that the email body contains the data.
7709 Syntax is <A HREF="mailto:%w%W">%w</A>
7714 LOC: Config.denyInfoList
7717 Usage: deny_info err_page_name acl
7718 or deny_info http://... acl
7719 or deny_info TCP_RESET acl
7721 This can be used to return a ERR_ page for requests which
7722 do not pass the 'http_access' rules. Squid remembers the last
7723 acl it evaluated in http_access, and if a 'deny_info' line exists
7724 for that ACL Squid returns a corresponding error page.
7726 The acl is typically the last acl on the http_access deny line which
7727 denied access. The exceptions to this rule are:
7728 - When Squid needs to request authentication credentials. It's then
7729 the first authentication related acl encountered
7730 - When none of the http_access lines matches. It's then the last
7731 acl processed on the last http_access line.
7732 - When the decision to deny access was made by an adaptation service,
7733 the acl name is the corresponding eCAP or ICAP service_name.
7735 NP: If providing your own custom error pages with error_directory
7736 you may also specify them by your custom file name:
7737 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7739 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7740 may be specified by prefixing the file name with the code and a colon.
7741 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7743 Alternatively you can tell Squid to reset the TCP connection
7744 by specifying TCP_RESET.
7746 Or you can specify an error URL or URL pattern. The browsers will
7747 get redirected to the specified URL after formatting tags have
7748 been replaced. Redirect will be done with 302 or 307 according to
7749 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7750 the URL. e.g. 303:http://example.com/
7753 %a - username (if available. Password NOT included)
7756 %E - Error description
7758 %H - Request domain name
7759 %i - Client IP Address
7761 %o - Message result from external ACL helper
7762 %p - Request Port number
7763 %P - Request Protocol name
7764 %R - Request URL path
7765 %T - Timestamp in RFC 1123 format
7766 %U - Full canonical URL from client
7767 (HTTPS URLs terminate with *)
7768 %u - Full canonical URL from client
7769 %w - Admin email from squid.conf
7771 %% - Literal percent (%) code
7776 OPTIONS INFLUENCING REQUEST FORWARDING
7777 -----------------------------------------------------------------------------
7780 NAME: nonhierarchical_direct
7782 LOC: Config.onoff.nonhierarchical_direct
7785 By default, Squid will send any non-hierarchical requests
7786 (not cacheable request type) direct to origin servers.
7788 When this is set to "off", Squid will prefer to send these
7789 requests to parents.
7791 Note that in most configurations, by turning this off you will only
7792 add latency to these request without any improvement in global hit
7795 This option only sets a preference. If the parent is unavailable a
7796 direct connection to the origin server may still be attempted. To
7797 completely prevent direct connections use never_direct.
7802 LOC: Config.onoff.prefer_direct
7805 Normally Squid tries to use parents for most requests. If you for some
7806 reason like it to first try going direct and only use a parent if
7807 going direct fails set this to on.
7809 By combining nonhierarchical_direct off and prefer_direct on you
7810 can set up Squid to use a parent as a backup path if going direct
7813 Note: If you want Squid to use parents for all requests see
7814 the never_direct directive. prefer_direct only modifies how Squid
7815 acts on cacheable requests.
7818 NAME: cache_miss_revalidate
7822 LOC: Config.onoff.cache_miss_revalidate
7824 RFC 7232 defines a conditional request mechanism to prevent
7825 response objects being unnecessarily transferred over the network.
7826 If that mechanism is used by the client and a cache MISS occurs
7827 it can prevent new cache entries being created.
7829 This option determines whether Squid on cache MISS will pass the
7830 client revalidation request to the server or tries to fetch new
7831 content for caching. It can be useful while the cache is mostly
7832 empty to more quickly have the cache populated by generating
7833 non-conditional GETs.
7835 When set to 'on' (default), Squid will pass all client If-* headers
7836 to the server. This permits server responses without a cacheable
7837 payload to be delivered and on MISS no new cache entry is created.
7839 When set to 'off' and if the request is cacheable, Squid will
7840 remove the clients If-Modified-Since and If-None-Match headers from
7841 the request sent to the server. This requests a 200 status response
7842 from the server to create a new cache entry with.
7847 LOC: Config.accessList.AlwaysDirect
7849 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7851 Usage: always_direct allow|deny [!]aclname ...
7853 Here you can use ACL elements to specify requests which should
7854 ALWAYS be forwarded by Squid to the origin servers without using
7855 any peers. For example, to always directly forward requests for
7856 local servers ignoring any parents or siblings you may have use
7859 acl local-servers dstdomain my.domain.net
7860 always_direct allow local-servers
7862 To always forward FTP requests directly, use
7865 always_direct allow FTP
7867 NOTE: There is a similar, but opposite option named
7868 'never_direct'. You need to be aware that "always_direct deny
7869 foo" is NOT the same thing as "never_direct allow foo". You
7870 may need to use a deny rule to exclude a more-specific case of
7871 some other rule. Example:
7873 acl local-external dstdomain external.foo.net
7874 acl local-servers dstdomain .foo.net
7875 always_direct deny local-external
7876 always_direct allow local-servers
7878 NOTE: If your goal is to make the client forward the request
7879 directly to the origin server bypassing Squid then this needs
7880 to be done in the client configuration. Squid configuration
7881 can only tell Squid how Squid should fetch the object.
7883 NOTE: This directive is not related to caching. The replies
7884 is cached as usual even if you use always_direct. To not cache
7885 the replies see the 'cache' directive.
7887 This clause supports both fast and slow acl types.
7888 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7893 LOC: Config.accessList.NeverDirect
7895 DEFAULT_DOC: Allow DNS results to be used for this request.
7897 Usage: never_direct allow|deny [!]aclname ...
7899 never_direct is the opposite of always_direct. Please read
7900 the description for always_direct if you have not already.
7902 With 'never_direct' you can use ACL elements to specify
7903 requests which should NEVER be forwarded directly to origin
7904 servers. For example, to force the use of a proxy for all
7905 requests, except those in your local domain use something like:
7907 acl local-servers dstdomain .foo.net
7908 never_direct deny local-servers
7909 never_direct allow all
7911 or if Squid is inside a firewall and there are local intranet
7912 servers inside the firewall use something like:
7914 acl local-intranet dstdomain .foo.net
7915 acl local-external dstdomain external.foo.net
7916 always_direct deny local-external
7917 always_direct allow local-intranet
7918 never_direct allow all
7920 This clause supports both fast and slow acl types.
7921 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7925 ADVANCED NETWORKING OPTIONS
7926 -----------------------------------------------------------------------------
7929 NAME: incoming_udp_average incoming_icp_average
7932 LOC: Config.comm_incoming.udp.average
7934 Heavy voodoo here. I can't even believe you are reading this.
7935 Are you crazy? Don't even think about adjusting these unless
7936 you understand the algorithms in comm_select.c first!
7939 NAME: incoming_tcp_average incoming_http_average
7942 LOC: Config.comm_incoming.tcp.average
7944 Heavy voodoo here. I can't even believe you are reading this.
7945 Are you crazy? Don't even think about adjusting these unless
7946 you understand the algorithms in comm_select.c first!
7949 NAME: incoming_dns_average
7952 LOC: Config.comm_incoming.dns.average
7954 Heavy voodoo here. I can't even believe you are reading this.
7955 Are you crazy? Don't even think about adjusting these unless
7956 you understand the algorithms in comm_select.c first!
7959 NAME: min_udp_poll_cnt min_icp_poll_cnt
7962 LOC: Config.comm_incoming.udp.min_poll
7964 Heavy voodoo here. I can't even believe you are reading this.
7965 Are you crazy? Don't even think about adjusting these unless
7966 you understand the algorithms in comm_select.c first!
7969 NAME: min_dns_poll_cnt
7972 LOC: Config.comm_incoming.dns.min_poll
7974 Heavy voodoo here. I can't even believe you are reading this.
7975 Are you crazy? Don't even think about adjusting these unless
7976 you understand the algorithms in comm_select.c first!
7979 NAME: min_tcp_poll_cnt min_http_poll_cnt
7982 LOC: Config.comm_incoming.tcp.min_poll
7984 Heavy voodoo here. I can't even believe you are reading this.
7985 Are you crazy? Don't even think about adjusting these unless
7986 you understand the algorithms in comm_select.c first!
7992 LOC: Config.accept_filter
7996 The name of an accept(2) filter to install on Squid's
7997 listen socket(s). This feature is perhaps specific to
7998 FreeBSD and requires support in the kernel.
8000 The 'httpready' filter delays delivering new connections
8001 to Squid until a full HTTP request has been received.
8002 See the accf_http(9) man page for details.
8004 The 'dataready' filter delays delivering new connections
8005 to Squid until there is some data to process.
8006 See the accf_dataready(9) man page for details.
8010 The 'data' filter delays delivering of new connections
8011 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
8012 You may optionally specify a number of seconds to wait by
8013 'data=N' where N is the number of seconds. Defaults to 30
8014 if not specified. See the tcp(7) man page for details.
8017 accept_filter httpready
8022 NAME: client_ip_max_connections
8024 LOC: Config.client_ip_max_connections
8026 DEFAULT_DOC: No limit.
8028 Set an absolute limit on the number of connections a single
8029 client IP can use. Any more than this and Squid will begin to drop
8030 new connections from the client until it closes some links.
8032 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
8033 connections from the client. For finer control use the ACL access controls.
8035 Requires client_db to be enabled (the default).
8037 WARNING: This may noticably slow down traffic received via external proxies
8038 or NAT devices and cause them to rebound error messages back to their clients.
8041 NAME: tcp_recv_bufsize
8045 DEFAULT_DOC: Use operating system TCP defaults.
8046 LOC: Config.tcpRcvBufsz
8048 Size of receive buffer to set for TCP sockets. Probably just
8049 as easy to change your kernel's default.
8050 Omit from squid.conf to use the default buffer size.
8055 -----------------------------------------------------------------------------
8062 LOC: Adaptation::Icap::TheConfig.onoff
8065 If you want to enable the ICAP module support, set this to on.
8068 NAME: icap_connect_timeout
8071 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
8074 This parameter specifies how long to wait for the TCP connect to
8075 the requested ICAP server to complete before giving up and either
8076 terminating the HTTP transaction or bypassing the failure.
8078 The default for optional services is peer_connect_timeout.
8079 The default for essential services is connect_timeout.
8080 If this option is explicitly set, its value applies to all services.
8083 NAME: icap_io_timeout
8087 DEFAULT_DOC: Use read_timeout.
8088 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
8091 This parameter specifies how long to wait for an I/O activity on
8092 an established, active ICAP connection before giving up and
8093 either terminating the HTTP transaction or bypassing the
8097 NAME: icap_service_failure_limit
8098 COMMENT: limit [in memory-depth time-units]
8099 TYPE: icap_service_failure_limit
8101 LOC: Adaptation::Icap::TheConfig
8104 The limit specifies the number of failures that Squid tolerates
8105 when establishing a new TCP connection with an ICAP service. If
8106 the number of failures exceeds the limit, the ICAP service is
8107 not used for new ICAP requests until it is time to refresh its
8110 A negative value disables the limit. Without the limit, an ICAP
8111 service will not be considered down due to connectivity failures
8112 between ICAP OPTIONS requests.
8114 Squid forgets ICAP service failures older than the specified
8115 value of memory-depth. The memory fading algorithm
8116 is approximate because Squid does not remember individual
8117 errors but groups them instead, splitting the option
8118 value into ten time slots of equal length.
8120 When memory-depth is 0 and by default this option has no
8121 effect on service failure expiration.
8123 Squid always forgets failures when updating service settings
8124 using an ICAP OPTIONS transaction, regardless of this option
8128 # suspend service usage after 10 failures in 5 seconds:
8129 icap_service_failure_limit 10 in 5 seconds
8132 NAME: icap_service_revival_delay
8135 LOC: Adaptation::Icap::TheConfig.service_revival_delay
8138 The delay specifies the number of seconds to wait after an ICAP
8139 OPTIONS request failure before requesting the options again. The
8140 failed ICAP service is considered "down" until fresh OPTIONS are
8143 The actual delay cannot be smaller than the hardcoded minimum
8144 delay of 30 seconds.
8147 NAME: icap_preview_enable
8151 LOC: Adaptation::Icap::TheConfig.preview_enable
8154 The ICAP Preview feature allows the ICAP server to handle the
8155 HTTP message by looking only at the beginning of the message body
8156 or even without receiving the body at all. In some environments,
8157 previews greatly speedup ICAP processing.
8159 During an ICAP OPTIONS transaction, the server may tell Squid what
8160 HTTP messages should be previewed and how big the preview should be.
8161 Squid will not use Preview if the server did not request one.
8163 To disable ICAP Preview for all ICAP services, regardless of
8164 individual ICAP server OPTIONS responses, set this option to "off".
8166 icap_preview_enable off
8169 NAME: icap_preview_size
8172 LOC: Adaptation::Icap::TheConfig.preview_size
8174 DEFAULT_DOC: No preview sent.
8176 The default size of preview data to be sent to the ICAP server.
8177 This value might be overwritten on a per server basis by OPTIONS requests.
8180 NAME: icap_206_enable
8184 LOC: Adaptation::Icap::TheConfig.allow206_enable
8187 206 (Partial Content) responses is an ICAP extension that allows the
8188 ICAP agents to optionally combine adapted and original HTTP message
8189 content. The decision to combine is postponed until the end of the
8190 ICAP response. Squid supports Partial Content extension by default.
8192 Activation of the Partial Content extension is negotiated with each
8193 ICAP service during OPTIONS exchange. Most ICAP servers should handle
8194 negotation correctly even if they do not support the extension, but
8195 some might fail. To disable Partial Content support for all ICAP
8196 services and to avoid any negotiation, set this option to "off".
8202 NAME: icap_default_options_ttl
8205 LOC: Adaptation::Icap::TheConfig.default_options_ttl
8208 The default TTL value for ICAP OPTIONS responses that don't have
8209 an Options-TTL header.
8212 NAME: icap_persistent_connections
8216 LOC: Adaptation::Icap::TheConfig.reuse_connections
8219 Whether or not Squid should use persistent connections to
8223 NAME: adaptation_send_client_ip icap_send_client_ip
8225 IFDEF: USE_ADAPTATION
8227 LOC: Adaptation::Config::send_client_ip
8230 If enabled, Squid shares HTTP client IP information with adaptation
8231 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
8232 For eCAP, Squid sets the libecap::metaClientIp transaction option.
8234 See also: adaptation_uses_indirect_client
8237 NAME: adaptation_send_username icap_send_client_username
8239 IFDEF: USE_ADAPTATION
8241 LOC: Adaptation::Config::send_username
8244 This sends authenticated HTTP client username (if available) to
8245 the adaptation service.
8247 For ICAP, the username value is encoded based on the
8248 icap_client_username_encode option and is sent using the header
8249 specified by the icap_client_username_header option.
8252 NAME: icap_client_username_header
8255 LOC: Adaptation::Icap::TheConfig.client_username_header
8256 DEFAULT: X-Client-Username
8258 ICAP request header name to use for adaptation_send_username.
8261 NAME: icap_client_username_encode
8265 LOC: Adaptation::Icap::TheConfig.client_username_encode
8268 Whether to base64 encode the authenticated client username.
8272 TYPE: icap_service_type
8274 LOC: Adaptation::Icap::TheConfig
8277 Defines a single ICAP service using the following format:
8279 icap_service id vectoring_point uri [option ...]
8282 an opaque identifier or name which is used to direct traffic to
8283 this specific service. Must be unique among all adaptation
8284 services in squid.conf.
8286 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8287 This specifies at which point of transaction processing the
8288 ICAP service should be activated. *_postcache vectoring points
8289 are not yet supported.
8291 uri: icap://servername:port/servicepath
8292 ICAP server and service location.
8293 icaps://servername:port/servicepath
8294 The "icap:" URI scheme is used for traditional ICAP server and
8295 service location (default port is 1344, connections are not
8296 encrypted). The "icaps:" URI scheme is for Secure ICAP
8297 services that use SSL/TLS-encrypted ICAP connections (by
8298 default, on port 11344).
8300 ICAP does not allow a single service to handle both REQMOD and RESPMOD
8301 transactions. Squid does not enforce that requirement. You can specify
8302 services with the same service_url and different vectoring_points. You
8303 can even specify multiple identical services as long as their
8304 service_names differ.
8306 To activate a service, use the adaptation_access directive. To group
8307 services, use adaptation_service_chain and adaptation_service_set.
8309 Service options are separated by white space. ICAP services support
8310 the following name=value options:
8313 If set to 'on' or '1', the ICAP service is treated as
8314 optional. If the service cannot be reached or malfunctions,
8315 Squid will try to ignore any errors and process the message as
8316 if the service was not enabled. No all ICAP errors can be
8317 bypassed. If set to 0, the ICAP service is treated as
8318 essential and all ICAP errors will result in an error page
8319 returned to the HTTP client.
8321 Bypass is off by default: services are treated as essential.
8324 If set to 'on' or '1', the ICAP service is allowed to
8325 dynamically change the current message adaptation plan by
8326 returning a chain of services to be used next. The services
8327 are specified using the X-Next-Services ICAP response header
8328 value, formatted as a comma-separated list of service names.
8329 Each named service should be configured in squid.conf. Other
8330 services are ignored. An empty X-Next-Services value results
8331 in an empty plan which ends the current adaptation.
8333 Dynamic adaptation plan may cross or cover multiple supported
8334 vectoring points in their natural processing order.
8336 Routing is not allowed by default: the ICAP X-Next-Services
8337 response header is ignored.
8340 Only has effect on split-stack systems. The default on those systems
8341 is to use IPv4-only connections. When set to 'on' this option will
8342 make Squid use IPv6-only connections to contact this ICAP service.
8344 on-overload=block|bypass|wait|force
8345 If the service Max-Connections limit has been reached, do
8346 one of the following for each new ICAP transaction:
8347 * block: send an HTTP error response to the client
8348 * bypass: ignore the "over-connected" ICAP service
8349 * wait: wait (in a FIFO queue) for an ICAP connection slot
8350 * force: proceed, ignoring the Max-Connections limit
8352 In SMP mode with N workers, each worker assumes the service
8353 connection limit is Max-Connections/N, even though not all
8354 workers may use a given service.
8356 The default value is "bypass" if service is bypassable,
8357 otherwise it is set to "wait".
8361 Use the given number as the Max-Connections limit, regardless
8362 of the Max-Connections value given by the service, if any.
8364 ==== ICAPS / TLS OPTIONS ====
8366 These options are used for Secure ICAP (icaps://....) services only.
8368 tls-cert=/path/to/ssl/certificate
8369 A client SSL certificate to use when connecting to
8372 tls-key=/path/to/ssl/key
8373 The private TLS/SSL key corresponding to sslcert above.
8374 If 'tls-key' is not specified 'tls-cert' is assumed to
8375 reference a combined PEM format file containing both the
8376 certificate and the key.
8378 tls-cipher=... The list of valid TLS/SSL ciphers to use when connecting
8379 to this icap server.
8382 The minimum TLS protocol version to permit. To control
8383 SSLv3 use the ssloptions= parameter.
8384 Supported Values: 1.0 (default), 1.1, 1.2
8386 tls-options=... Specify various OpenSSL library options:
8388 NO_SSLv3 Disallow the use of SSLv3
8390 NO_TLSv1 Disallow the use of TLSv1.0
8391 NO_TLSv1_1 Disallow the use of TLSv1.1
8392 NO_TLSv1_2 Disallow the use of TLSv1.2
8395 Always create a new key when using
8396 temporary/ephemeral DH key exchanges
8398 ALL Enable various bug workarounds
8399 suggested as "harmless" by OpenSSL
8400 Be warned that this reduces SSL/TLS
8401 strength to some attacks.
8403 See the OpenSSL SSL_CTX_set_options documentation for a
8404 more complete list. Options relevant only to SSLv2 are
8407 tls-cafile= PEM file containing CA certificates to use when verifying
8408 the icap server certificate.
8409 Use to specify intermediate CA certificate(s) if not sent
8410 by the server. Or the full CA chain for the server when
8411 using the tls-no-default-ca flag.
8412 May be repeated to load multiple files.
8414 tls-capath=... A directory containing additional CA certificates to
8415 use when verifying the icap server certificate.
8416 Requires OpenSSL or LibreSSL.
8418 tls-crlfile=... A certificate revocation list file to use when
8419 verifying the icap server certificate.
8421 tls-flags=... Specify various flags modifying the Squid TLS implementation:
8424 Accept certificates even if they fail to
8427 Don't verify the icap server certificate
8428 matches the server name
8431 Do no use the system default Trusted CA.
8433 tls-domain= The icap server name as advertised in it's certificate.
8434 Used for verifying the correctness of the received icap
8435 server certificate. If not specified the icap server
8436 hostname extracted from ICAP URI will be used.
8438 Older icap_service format without optional named parameters is
8439 deprecated but supported for backward compatibility.
8442 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
8443 icap_service svcLogger reqmod_precache icaps://icap2.mydomain.net:11344/reqmod routing=on
8447 TYPE: icap_class_type
8452 This deprecated option was documented to define an ICAP service
8453 chain, even though it actually defined a set of similar, redundant
8454 services, and the chains were not supported.
8456 To define a set of redundant services, please use the
8457 adaptation_service_set directive. For service chains, use
8458 adaptation_service_chain.
8462 TYPE: icap_access_type
8467 This option is deprecated. Please use adaptation_access, which
8468 has the same ICAP functionality, but comes with better
8469 documentation, and eCAP support.
8474 -----------------------------------------------------------------------------
8481 LOC: Adaptation::Ecap::TheConfig.onoff
8484 Controls whether eCAP support is enabled.
8488 TYPE: ecap_service_type
8490 LOC: Adaptation::Ecap::TheConfig
8493 Defines a single eCAP service
8495 ecap_service id vectoring_point uri [option ...]
8498 an opaque identifier or name which is used to direct traffic to
8499 this specific service. Must be unique among all adaptation
8500 services in squid.conf.
8502 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8503 This specifies at which point of transaction processing the
8504 eCAP service should be activated. *_postcache vectoring points
8505 are not yet supported.
8507 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
8508 Squid uses the eCAP service URI to match this configuration
8509 line with one of the dynamically loaded services. Each loaded
8510 eCAP service must have a unique URI. Obtain the right URI from
8511 the service provider.
8513 To activate a service, use the adaptation_access directive. To group
8514 services, use adaptation_service_chain and adaptation_service_set.
8516 Service options are separated by white space. eCAP services support
8517 the following name=value options:
8520 If set to 'on' or '1', the eCAP service is treated as optional.
8521 If the service cannot be reached or malfunctions, Squid will try
8522 to ignore any errors and process the message as if the service
8523 was not enabled. No all eCAP errors can be bypassed.
8524 If set to 'off' or '0', the eCAP service is treated as essential
8525 and all eCAP errors will result in an error page returned to the
8528 Bypass is off by default: services are treated as essential.
8531 If set to 'on' or '1', the eCAP service is allowed to
8532 dynamically change the current message adaptation plan by
8533 returning a chain of services to be used next.
8535 Dynamic adaptation plan may cross or cover multiple supported
8536 vectoring points in their natural processing order.
8538 Routing is not allowed by default.
8540 Older ecap_service format without optional named parameters is
8541 deprecated but supported for backward compatibility.
8545 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
8546 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
8549 NAME: loadable_modules
8551 IFDEF: USE_LOADABLE_MODULES
8552 LOC: Config.loadable_module_names
8555 Instructs Squid to load the specified dynamic module(s) or activate
8556 preloaded module(s).
8558 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
8562 MESSAGE ADAPTATION OPTIONS
8563 -----------------------------------------------------------------------------
8566 NAME: adaptation_service_set
8567 TYPE: adaptation_service_set_type
8568 IFDEF: USE_ADAPTATION
8573 Configures an ordered set of similar, redundant services. This is
8574 useful when hot standby or backup adaptation servers are available.
8576 adaptation_service_set set_name service_name1 service_name2 ...
8578 The named services are used in the set declaration order. The first
8579 applicable adaptation service from the set is used first. The next
8580 applicable service is tried if and only if the transaction with the
8581 previous service fails and the message waiting to be adapted is still
8584 When adaptation starts, broken services are ignored as if they were
8585 not a part of the set. A broken service is a down optional service.
8587 The services in a set must be attached to the same vectoring point
8588 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8590 If all services in a set are optional then adaptation failures are
8591 bypassable. If all services in the set are essential, then a
8592 transaction failure with one service may still be retried using
8593 another service from the set, but when all services fail, the master
8594 transaction fails as well.
8596 A set may contain a mix of optional and essential services, but that
8597 is likely to lead to surprising results because broken services become
8598 ignored (see above), making previously bypassable failures fatal.
8599 Technically, it is the bypassability of the last failed service that
8602 See also: adaptation_access adaptation_service_chain
8605 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
8606 adaptation service_set svcLogger loggerLocal loggerRemote
8609 NAME: adaptation_service_chain
8610 TYPE: adaptation_service_chain_type
8611 IFDEF: USE_ADAPTATION
8616 Configures a list of complementary services that will be applied
8617 one-by-one, forming an adaptation chain or pipeline. This is useful
8618 when Squid must perform different adaptations on the same message.
8620 adaptation_service_chain chain_name service_name1 svc_name2 ...
8622 The named services are used in the chain declaration order. The first
8623 applicable adaptation service from the chain is used first. The next
8624 applicable service is applied to the successful adaptation results of
8625 the previous service in the chain.
8627 When adaptation starts, broken services are ignored as if they were
8628 not a part of the chain. A broken service is a down optional service.
8630 Request satisfaction terminates the adaptation chain because Squid
8631 does not currently allow declaration of RESPMOD services at the
8632 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8634 The services in a chain must be attached to the same vectoring point
8635 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8637 A chain may contain a mix of optional and essential services. If an
8638 essential adaptation fails (or the failure cannot be bypassed for
8639 other reasons), the master transaction fails. Otherwise, the failure
8640 is bypassed as if the failed adaptation service was not in the chain.
8642 See also: adaptation_access adaptation_service_set
8645 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8648 NAME: adaptation_access
8649 TYPE: adaptation_access_type
8650 IFDEF: USE_ADAPTATION
8653 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8655 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8657 adaptation_access service_name allow|deny [!]aclname...
8658 adaptation_access set_name allow|deny [!]aclname...
8660 At each supported vectoring point, the adaptation_access
8661 statements are processed in the order they appear in this
8662 configuration file. Statements pointing to the following services
8663 are ignored (i.e., skipped without checking their ACL):
8665 - services serving different vectoring points
8666 - "broken-but-bypassable" services
8667 - "up" services configured to ignore such transactions
8668 (e.g., based on the ICAP Transfer-Ignore header).
8670 When a set_name is used, all services in the set are checked
8671 using the same rules, to find the first applicable one. See
8672 adaptation_service_set for details.
8674 If an access list is checked and there is a match, the
8675 processing stops: For an "allow" rule, the corresponding
8676 adaptation service is used for the transaction. For a "deny"
8677 rule, no adaptation service is activated.
8679 It is currently not possible to apply more than one adaptation
8680 service at the same vectoring point to the same HTTP transaction.
8682 See also: icap_service and ecap_service
8685 adaptation_access service_1 allow all
8688 NAME: adaptation_service_iteration_limit
8690 IFDEF: USE_ADAPTATION
8691 LOC: Adaptation::Config::service_iteration_limit
8694 Limits the number of iterations allowed when applying adaptation
8695 services to a message. If your longest adaptation set or chain
8696 may have more than 16 services, increase the limit beyond its
8697 default value of 16. If detecting infinite iteration loops sooner
8698 is critical, make the iteration limit match the actual number
8699 of services in your longest adaptation set or chain.
8701 Infinite adaptation loops are most likely with routing services.
8703 See also: icap_service routing=1
8706 NAME: adaptation_masterx_shared_names
8708 IFDEF: USE_ADAPTATION
8709 LOC: Adaptation::Config::masterx_shared_name
8712 For each master transaction (i.e., the HTTP request and response
8713 sequence, including all related ICAP and eCAP exchanges), Squid
8714 maintains a table of metadata. The table entries are (name, value)
8715 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8716 with the master transaction.
8718 This option specifies the table entry names that Squid must accept
8719 from and forward to the adaptation transactions.
8721 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8722 shared table by returning an ICAP header field with a name
8723 specified in adaptation_masterx_shared_names.
8725 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8726 shared table by implementing the libecap::visitEachOption() API
8727 to provide an option with a name specified in
8728 adaptation_masterx_shared_names.
8730 Squid will store and forward the set entry to subsequent adaptation
8731 transactions within the same master transaction scope.
8733 Only one shared entry name is supported at this time.
8736 # share authentication information among ICAP services
8737 adaptation_masterx_shared_names X-Subscriber-ID
8740 NAME: adaptation_meta
8742 IFDEF: USE_ADAPTATION
8743 LOC: Adaptation::Config::metaHeaders
8746 This option allows Squid administrator to add custom ICAP request
8747 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8748 Use it to pass custom authentication tokens and other
8749 transaction-state related meta information to an ICAP/eCAP service.
8751 The addition of a meta header is ACL-driven:
8752 adaptation_meta name value [!]aclname ...
8754 Processing for a given header name stops after the first ACL list match.
8755 Thus, it is impossible to add two headers with the same name. If no ACL
8756 lists match for a given header name, no such header is added. For
8759 # do not debug transactions except for those that need debugging
8760 adaptation_meta X-Debug 1 needs_debugging
8762 # log all transactions except for those that must remain secret
8763 adaptation_meta X-Log 1 !keep_secret
8765 # mark transactions from users in the "G 1" group
8766 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8768 The "value" parameter may be a regular squid.conf token or a "double
8769 quoted string". Within the quoted string, use backslash (\) to escape
8770 any character, which is currently only useful for escaping backslashes
8771 and double quotes. For example,
8772 "this string has one backslash (\\) and two \"quotes\""
8774 Used adaptation_meta header values may be logged via %note
8775 logformat code. If multiple adaptation_meta headers with the same name
8776 are used during master transaction lifetime, the header values are
8777 logged in the order they were used and duplicate values are ignored
8778 (only the first repeated value will be logged).
8784 LOC: Adaptation::Icap::TheConfig.repeat
8785 DEFAULT_IF_NONE: deny all
8787 This ACL determines which retriable ICAP transactions are
8788 retried. Transactions that received a complete ICAP response
8789 and did not have to consume or produce HTTP bodies to receive
8790 that response are usually retriable.
8792 icap_retry allow|deny [!]aclname ...
8794 Squid automatically retries some ICAP I/O timeouts and errors
8795 due to persistent connection race conditions.
8797 See also: icap_retry_limit
8800 NAME: icap_retry_limit
8803 LOC: Adaptation::Icap::TheConfig.repeat_limit
8805 DEFAULT_DOC: No retries are allowed.
8807 Limits the number of retries allowed.
8809 Communication errors due to persistent connection race
8810 conditions are unavoidable, automatically retried, and do not
8811 count against this limit.
8813 See also: icap_retry
8819 -----------------------------------------------------------------------------
8822 NAME: check_hostnames
8825 LOC: Config.onoff.check_hostnames
8827 For security and stability reasons Squid can check
8828 hostnames for Internet standard RFC compliance. If you want
8829 Squid to perform these checks turn this directive on.
8832 NAME: allow_underscore
8835 LOC: Config.onoff.allow_underscore
8837 Underscore characters is not strictly allowed in Internet hostnames
8838 but nevertheless used by many sites. Set this to off if you want
8839 Squid to be strict about the standard.
8840 This check is performed only when check_hostnames is set to on.
8843 NAME: dns_retransmit_interval
8846 LOC: Config.Timeout.idns_retransmit
8848 Initial retransmit interval for DNS queries. The interval is
8849 doubled each time all configured DNS servers have been tried.
8855 LOC: Config.Timeout.idns_query
8857 DNS Query timeout. If no response is received to a DNS query
8858 within this time all DNS servers for the queried domain
8859 are assumed to be unavailable.
8862 NAME: dns_packet_max
8864 DEFAULT_DOC: EDNS disabled
8866 LOC: Config.dns.packet_max
8868 Maximum number of bytes packet size to advertise via EDNS.
8869 Set to "none" to disable EDNS large packet support.
8871 For legacy reasons DNS UDP replies will default to 512 bytes which
8872 is too small for many responses. EDNS provides a means for Squid to
8873 negotiate receiving larger responses back immediately without having
8874 to failover with repeat requests. Responses larger than this limit
8875 will retain the old behaviour of failover to TCP DNS.
8877 Squid has no real fixed limit internally, but allowing packet sizes
8878 over 1500 bytes requires network jumbogram support and is usually not
8881 WARNING: The RFC also indicates that some older resolvers will reply
8882 with failure of the whole request if the extension is added. Some
8883 resolvers have already been identified which will reply with mangled
8884 EDNS response on occasion. Usually in response to many-KB jumbogram
8885 sizes being advertised by Squid.
8886 Squid will currently treat these both as an unable-to-resolve domain
8887 even if it would be resolvable without EDNS.
8894 DEFAULT_DOC: Search for single-label domain names is disabled.
8895 LOC: Config.onoff.res_defnames
8897 Normally the RES_DEFNAMES resolver option is disabled
8898 (see res_init(3)). This prevents caches in a hierarchy
8899 from interpreting single-component hostnames locally. To allow
8900 Squid to handle single-component names, enable this option.
8903 NAME: dns_multicast_local
8907 DEFAULT_DOC: Search for .local and .arpa names is disabled.
8908 LOC: Config.onoff.dns_mdns
8910 When set to on, Squid sends multicast DNS lookups on the local
8911 network for domains ending in .local and .arpa.
8912 This enables local servers and devices to be contacted in an
8913 ad-hoc or zero-configuration network environment.
8916 NAME: dns_nameservers
8919 DEFAULT_DOC: Use operating system definitions
8920 LOC: Config.dns_nameservers
8922 Use this if you want to specify a list of DNS name servers
8923 (IP addresses) to use instead of those given in your
8924 /etc/resolv.conf file.
8926 On Windows platforms, if no value is specified here or in
8927 the /etc/resolv.conf file, the list of DNS name servers are
8928 taken from the Windows registry, both static and dynamic DHCP
8929 configurations are supported.
8931 Example: dns_nameservers 10.0.0.1 192.172.0.4
8936 DEFAULT: @DEFAULT_HOSTS@
8937 LOC: Config.etcHostsPath
8939 Location of the host-local IP name-address associations
8940 database. Most Operating Systems have such a file on different
8942 - Un*X & Linux: /etc/hosts
8943 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
8944 (%SystemRoot% value install default is c:\winnt)
8945 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
8946 (%SystemRoot% value install default is c:\windows)
8947 - Windows 9x/Me: %windir%\hosts
8948 (%windir% value is usually c:\windows)
8949 - Cygwin: /etc/hosts
8951 The file contains newline-separated definitions, in the
8952 form ip_address_in_dotted_form name [name ...] names are
8953 whitespace-separated. Lines beginning with an hash (#)
8954 character are comments.
8956 The file is checked at startup and upon configuration.
8957 If set to 'none', it won't be checked.
8958 If append_domain is used, that domain will be added to
8959 domain-local (i.e. not containing any dot character) host
8965 LOC: Config.appendDomain
8967 DEFAULT_DOC: Use operating system definitions
8969 Appends local domain name to hostnames without any dots in
8970 them. append_domain must begin with a period.
8972 Be warned there are now Internet names with no dots in
8973 them using only top-domain names, so setting this may
8974 cause some Internet sites to become unavailable.
8977 append_domain .yourdomain.com
8980 NAME: ignore_unknown_nameservers
8982 LOC: Config.onoff.ignore_unknown_nameservers
8985 By default Squid checks that DNS responses are received
8986 from the same IP addresses they are sent to. If they
8987 don't match, Squid ignores the response and writes a warning
8988 message to cache.log. You can allow responses from unknown
8989 nameservers by setting this option to 'off'.
8995 LOC: Config.dns.v4_first
8997 With the IPv6 Internet being as fast or faster than IPv4 Internet
8998 for most networks Squid prefers to contact websites over IPv6.
9000 This option reverses the order of preference to make Squid contact
9001 dual-stack websites over IPv4 first. Squid will still perform both
9002 IPv6 and IPv4 DNS lookups before connecting.
9005 This option will restrict the situations under which IPv6
9006 connectivity is used (and tested). Hiding network problems
9007 which would otherwise be detected and warned about.
9011 COMMENT: (number of entries)
9014 LOC: Config.ipcache.size
9016 Maximum number of DNS IP cache entries.
9023 LOC: Config.ipcache.low
9030 LOC: Config.ipcache.high
9032 The size, low-, and high-water marks for the IP cache.
9035 NAME: fqdncache_size
9036 COMMENT: (number of entries)
9039 LOC: Config.fqdncache.size
9041 Maximum number of FQDN cache entries.
9046 -----------------------------------------------------------------------------
9049 NAME: configuration_includes_quoted_values
9051 TYPE: configuration_includes_quoted_values
9053 LOC: ConfigParser::RecognizeQuotedValues
9055 If set, Squid will recognize each "quoted string" after a configuration
9056 directive as a single parameter. The quotes are stripped before the
9057 parameter value is interpreted or used.
9058 See "Values with spaces, quotes, and other special characters"
9059 section for more details.
9066 LOC: Config.onoff.mem_pools
9068 If set, Squid will keep pools of allocated (but unused) memory
9069 available for future use. If memory is a premium on your
9070 system and you believe your malloc library outperforms Squid
9071 routines, disable this.
9074 NAME: memory_pools_limit
9078 LOC: Config.MemPools.limit
9080 Used only with memory_pools on:
9081 memory_pools_limit 50 MB
9083 If set to a non-zero value, Squid will keep at most the specified
9084 limit of allocated (but unused) memory in memory pools. All free()
9085 requests that exceed this limit will be handled by your malloc
9086 library. Squid does not pre-allocate any memory, just safe-keeps
9087 objects that otherwise would be free()d. Thus, it is safe to set
9088 memory_pools_limit to a reasonably high value even if your
9089 configuration will use less memory.
9091 If set to none, Squid will keep all memory it can. That is, there
9092 will be no limit on the total amount of memory used for safe-keeping.
9094 To disable memory allocation optimization, do not set
9095 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
9097 An overhead for maintaining memory pools is not taken into account
9098 when the limit is checked. This overhead is close to four bytes per
9099 object kept. However, pools may actually _save_ memory because of
9100 reduced memory thrashing in your malloc library.
9104 COMMENT: on|off|transparent|truncate|delete
9107 LOC: opt_forwarded_for
9109 If set to "on", Squid will append your client's IP address
9110 in the HTTP requests it forwards. By default it looks like:
9112 X-Forwarded-For: 192.1.2.3
9114 If set to "off", it will appear as
9116 X-Forwarded-For: unknown
9118 If set to "transparent", Squid will not alter the
9119 X-Forwarded-For header in any way.
9121 If set to "delete", Squid will delete the entire
9122 X-Forwarded-For header.
9124 If set to "truncate", Squid will remove all existing
9125 X-Forwarded-For entries, and place the client IP as the sole entry.
9128 NAME: cachemgr_passwd
9129 TYPE: cachemgrpasswd
9131 DEFAULT_DOC: No password. Actions which require password are denied.
9132 LOC: Config.passwd_list
9134 Specify passwords for cachemgr operations.
9136 Usage: cachemgr_passwd password action action ...
9138 Some valid actions are (see cache manager menu for a full list):
9178 * Indicates actions which will not be performed without a
9179 valid password, others can be performed if not listed here.
9181 To disable an action, set the password to "disable".
9182 To allow performing an action without a password, set the
9185 Use the keyword "all" to set the same password for all actions.
9188 cachemgr_passwd secret shutdown
9189 cachemgr_passwd lesssssssecret info stats/objects
9190 cachemgr_passwd disable all
9197 LOC: Config.onoff.client_db
9199 If you want to disable collecting per-client statistics,
9200 turn off client_db here.
9203 NAME: refresh_all_ims
9207 LOC: Config.onoff.refresh_all_ims
9209 When you enable this option, squid will always check
9210 the origin server for an update when a client sends an
9211 If-Modified-Since request. Many browsers use IMS
9212 requests when the user requests a reload, and this
9213 ensures those clients receive the latest version.
9215 By default (off), squid may return a Not Modified response
9216 based on the age of the cached version.
9219 NAME: reload_into_ims
9220 IFDEF: USE_HTTP_VIOLATIONS
9224 LOC: Config.onoff.reload_into_ims
9226 When you enable this option, client no-cache or ``reload''
9227 requests will be changed to If-Modified-Since requests.
9228 Doing this VIOLATES the HTTP standard. Enabling this
9229 feature could make you liable for problems which it
9232 see also refresh_pattern for a more selective approach.
9235 NAME: connect_retries
9237 LOC: Config.connect_retries
9239 DEFAULT_DOC: Do not retry failed connections.
9241 This sets the maximum number of connection attempts made for each
9242 TCP connection. The connect_retries attempts must all still
9243 complete within the connection timeout period.
9245 The default is not to re-try if the first connection attempt fails.
9246 The (not recommended) maximum is 10 tries.
9248 A warning message will be generated if it is set to a too-high
9249 value and the configured value will be over-ridden.
9251 Note: These re-tries are in addition to forward_max_tries
9252 which limit how many different addresses may be tried to find
9256 NAME: retry_on_error
9258 LOC: Config.retry.onerror
9261 If set to ON Squid will automatically retry requests when
9262 receiving an error response with status 403 (Forbidden),
9263 500 (Internal Error), 501 or 503 (Service not available).
9264 Status 502 and 504 (Gateway errors) are always retried.
9266 This is mainly useful if you are in a complex cache hierarchy to
9267 work around access control errors.
9269 NOTE: This retry will attempt to find another working destination.
9270 Which is different from the server which just failed.
9273 NAME: as_whois_server
9275 LOC: Config.as_whois_server
9276 DEFAULT: whois.ra.net
9278 WHOIS server to query for AS numbers. NOTE: AS numbers are
9279 queried only when Squid starts up, not for every request.
9284 LOC: Config.onoff.offline
9287 Enable this option and Squid will never try to validate cached
9291 NAME: uri_whitespace
9292 TYPE: uri_whitespace
9293 LOC: Config.uri_whitespace
9296 What to do with requests that have whitespace characters in the
9299 strip: The whitespace characters are stripped out of the URL.
9300 This is the behavior recommended by RFC2396 and RFC3986
9301 for tolerant handling of generic URI.
9302 NOTE: This is one difference between generic URI and HTTP URLs.
9304 deny: The request is denied. The user receives an "Invalid
9306 This is the behaviour recommended by RFC2616 for safe
9307 handling of HTTP request URL.
9309 allow: The request is allowed and the URI is not changed. The
9310 whitespace characters remain in the URI. Note the
9311 whitespace is passed to redirector processes if they
9313 Note this may be considered a violation of RFC2616
9314 request parsing where whitespace is prohibited in the
9317 encode: The request is allowed and the whitespace characters are
9318 encoded according to RFC1738.
9320 chop: The request is allowed and the URI is chopped at the
9324 NOTE the current Squid implementation of encode and chop violates
9325 RFC2616 by not using a 301 redirect after altering the URL.
9330 LOC: Config.chroot_dir
9333 Specifies a directory where Squid should do a chroot() while
9334 initializing. This also causes Squid to fully drop root
9335 privileges after initializing. This means, for example, if you
9336 use a HTTP port less than 1024 and try to reconfigure, you may
9337 get an error saying that Squid can not open the port.
9340 NAME: balance_on_multiple_ip
9342 LOC: Config.onoff.balance_on_multiple_ip
9345 Modern IP resolvers in squid sort lookup results by preferred access.
9346 By default squid will use these IP in order and only rotates to
9347 the next listed when the most preffered fails.
9349 Some load balancing servers based on round robin DNS have been
9350 found not to preserve user session state across requests
9351 to different IP addresses.
9353 Enabling this directive Squid rotates IP's per request.
9356 NAME: pipeline_prefetch
9357 TYPE: pipelinePrefetch
9358 LOC: Config.pipeline_max_prefetch
9360 DEFAULT_DOC: Do not pre-parse pipelined requests.
9362 HTTP clients may send a pipeline of 1+N requests to Squid using a
9363 single connection, without waiting for Squid to respond to the first
9364 of those requests. This option limits the number of concurrent
9365 requests Squid will try to handle in parallel. If set to N, Squid
9366 will try to receive and process up to 1+N requests on the same
9367 connection concurrently.
9369 Defaults to 0 (off) for bandwidth management and access logging
9372 NOTE: pipelining requires persistent connections to clients.
9374 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
9377 NAME: high_response_time_warning
9380 LOC: Config.warnings.high_rptm
9382 DEFAULT_DOC: disabled.
9384 If the one-minute median response time exceeds this value,
9385 Squid prints a WARNING with debug level 0 to get the
9386 administrators attention. The value is in milliseconds.
9389 NAME: high_page_fault_warning
9391 LOC: Config.warnings.high_pf
9393 DEFAULT_DOC: disabled.
9395 If the one-minute average page fault rate exceeds this
9396 value, Squid prints a WARNING with debug level 0 to get
9397 the administrators attention. The value is in page faults
9401 NAME: high_memory_warning
9403 LOC: Config.warnings.high_memory
9404 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
9406 DEFAULT_DOC: disabled.
9408 If the memory usage (as determined by gnumalloc, if available and used)
9409 exceeds this amount, Squid prints a WARNING with debug level 0 to get
9410 the administrators attention.
9412 # TODO: link high_memory_warning to mempools?
9414 NAME: sleep_after_fork
9415 COMMENT: (microseconds)
9417 LOC: Config.sleep_after_fork
9420 When this is set to a non-zero value, the main Squid process
9421 sleeps the specified number of microseconds after a fork()
9422 system call. This sleep may help the situation where your
9423 system reports fork() failures due to lack of (virtual)
9424 memory. Note, however, if you have a lot of child
9425 processes, these sleep delays will add up and your
9426 Squid will not service requests for some amount of time
9427 until all the child processes have been started.
9428 On Windows value less then 1000 (1 milliseconds) are
9432 NAME: windows_ipaddrchangemonitor
9433 IFDEF: _SQUID_WINDOWS_
9437 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
9439 On Windows Squid by default will monitor IP address changes and will
9440 reconfigure itself after any detected event. This is very useful for
9441 proxies connected to internet with dial-up interfaces.
9442 In some cases (a Proxy server acting as VPN gateway is one) it could be
9443 desiderable to disable this behaviour setting this to 'off'.
9444 Note: after changing this, Squid service must be restarted.
9449 IFDEF: USE_SQUID_EUI
9451 LOC: Eui::TheConfig.euiLookup
9453 Whether to lookup the EUI or MAC address of a connected client.
9456 NAME: max_filedescriptors max_filedesc
9459 DEFAULT_DOC: Use operating system limits set by ulimit.
9460 LOC: Config.max_filedescriptors
9462 Reduce the maximum number of filedescriptors supported below
9463 the usual operating system defaults.
9465 Remove from squid.conf to inherit the current ulimit setting.
9467 Note: Changing this requires a restart of Squid. Also
9468 not all I/O types supports large values (eg on Windows).
9471 NAME: force_request_body_continuation
9473 LOC: Config.accessList.forceRequestBodyContinuation
9475 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
9477 This option controls how Squid handles data upload requests from HTTP
9478 and FTP agents that require a "Please Continue" control message response
9479 to actually send the request body to Squid. It is mostly useful in
9480 adaptation environments.
9482 When Squid receives an HTTP request with an "Expect: 100-continue"
9483 header or an FTP upload command (e.g., STOR), Squid normally sends the
9484 request headers or FTP command information to an adaptation service (or
9485 peer) and waits for a response. Most adaptation services (and some
9486 broken peers) may not respond to Squid at that stage because they may
9487 decide to wait for the HTTP request body or FTP data transfer. However,
9488 that request body or data transfer may never come because Squid has not
9489 responded with the HTTP 100 or FTP 150 (Please Continue) control message
9490 to the request sender yet!
9492 An allow match tells Squid to respond with the HTTP 100 or FTP 150
9493 (Please Continue) control message on its own, before forwarding the
9494 request to an adaptation service or peer. Such a response usually forces
9495 the request sender to proceed with sending the body. A deny match tells
9496 Squid to delay that control response until the origin server confirms
9497 that the request body is needed. Delaying is the default behavior.
projects / thirdparty / squid.git / blob