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 specifications
766 %LOGIN Authenticated user login name
767 %un A user name. Expands to the first available name
768 from the following list of information sources:
769 - authenticated user name, like %ul or %LOGIN
770 - user name sent by an external ACL, like %EXT_USER
771 - SSL client name, like %us in logformat
772 - ident user name, like %ui in logformat
773 %EXT_USER Username from previous external acl
774 %EXT_LOG Log details from previous external acl
775 %EXT_TAG Tag from previous external acl
776 %IDENT Ident user name
778 %SRCPORT Client source port
781 %PROTO Requested URL scheme
783 %PATH Requested URL path
784 %METHOD Request method
785 %MYADDR Squid interface address
786 %MYPORT Squid http_port number
787 %PATH Requested URL-path (including query-string if any)
788 %USER_CERT SSL User certificate in PEM format
789 %USER_CERTCHAIN SSL User certificate chain in PEM format
790 %USER_CERT_xx SSL User certificate subject attribute xx
791 %USER_CA_CERT_xx SSL User certificate issuer attribute xx
792 %ssl::>sni SSL client SNI sent to Squid
793 %ssl::<cert_subject SSL server certificate DN
794 %ssl::<cert_issuer SSL server certificate issuer DN
796 %>{Header} HTTP request header "Header"
798 HTTP request header "Hdr" list member "member"
800 HTTP request header list member using ; as
801 list separator. ; can be any non-alphanumeric
804 %<{Header} HTTP reply header "Header"
806 HTTP reply header "Hdr" list member "member"
808 HTTP reply header list member using ; as
809 list separator. ; can be any non-alphanumeric
812 %ACL The name of the ACL being tested.
813 %DATA The ACL arguments. If not used then any arguments
814 is automatically added at the end of the line
816 NOTE: this will encode the arguments as one token,
817 whereas the default will pass each separately.
819 %% The percent sign. Useful for helpers which need
820 an unchanging input format.
823 General request syntax:
825 [channel-ID] FORMAT-values [acl-values ...]
828 FORMAT-values consists of transaction details expanded with
829 whitespace separation per the config file FORMAT specification
830 using the FORMAT macros listed above.
832 acl-values consists of any string specified in the referencing
833 config 'acl ... external' line. see the "acl external" directive.
835 Request values sent to the helper are URL escaped to protect
836 each value in requests against whitespaces.
838 If using protocol=2.5 then the request sent to the helper is not
839 URL escaped to protect against whitespace.
841 NOTE: protocol=3.0 is deprecated as no longer necessary.
843 When using the concurrency= option the protocol is changed by
844 introducing a query channel tag in front of the request/response.
845 The query channel tag is a number between 0 and concurrency-1.
846 This value must be echoed back unchanged to Squid as the first part
847 of the response relating to its request.
850 The helper receives lines expanded per the above format specification
851 and for each input line returns 1 line starting with OK/ERR/BH result
852 code and optionally followed by additional keywords with more details.
855 General result syntax:
857 [channel-ID] result keyword=value ...
859 Result consists of one of the codes:
862 the ACL test produced a match.
865 the ACL test does not produce a match.
868 An internal error occurred in the helper, preventing
869 a result being identified.
871 The meaning of 'a match' is determined by your squid.conf
872 access control configuration. See the Squid wiki for details.
876 user= The users name (login)
878 password= The users password (for login= cache_peer option)
880 message= Message describing the reason for this response.
881 Available as %o in error pages.
882 Useful on (ERR and BH results).
884 tag= Apply a tag to a request. Only sets a tag once,
885 does not alter existing tags.
887 log= String to be logged in access.log. Available as
888 %ea in logformat specifications.
890 clt_conn_tag= Associates a TAG with the client TCP connection.
891 Please see url_rewrite_program related documentation
894 Any keywords may be sent on any response whether OK, ERR or BH.
896 All response keyword values need to be a single token with URL
897 escaping, or enclosed in double quotes (") and escaped using \ on
898 any double quotes or \ characters within the value. The wrapping
899 double quotes are removed before the value is interpreted by Squid.
900 \r and \n are also replace by CR and LF.
902 Some example key values:
906 user="J. \"Bob\" Smith"
913 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
914 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
915 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
916 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
917 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
920 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
921 DEFAULT: localhost src 127.0.0.1/32 ::1
922 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
923 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
925 Defining an Access List
927 Every access list definition must begin with an aclname and acltype,
928 followed by either type-specific arguments or a quoted filename that
931 acl aclname acltype argument ...
932 acl aclname acltype "file" ...
934 When using "file", the file should contain one item per line.
936 Some acl types supports options which changes their default behaviour.
937 The available options are:
939 -i,+i By default, regular expressions are CASE-SENSITIVE. To make them
940 case-insensitive, use the -i option. To return case-sensitive
941 use the +i option between patterns, or make a new ACL line
944 -n Disable lookups and address type conversions. If lookup or
945 conversion is required because the parameter type (IP or
946 domain name) does not match the message address type (domain
947 name or IP), then the ACL would immediately declare a mismatch
948 without any warnings or lookups.
950 -- Used to stop processing all options, in the case the first acl
951 value has '-' character as first character (for example the '-'
952 is a valid domain name)
954 Some acl types require suspending the current request in order
955 to access some external data source.
956 Those which do are marked with the tag [slow], those which
957 don't are marked as [fast].
958 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
959 for further information
961 ***** ACL TYPES AVAILABLE *****
963 acl aclname src ip-address/mask ... # clients IP address [fast]
964 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
965 acl aclname dst [-n] ip-address/mask ... # URL host's IP address [slow]
966 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
968 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
970 # The 'arp' ACL code is not portable to all operating systems.
971 # It works on Linux, Solaris, Windows, FreeBSD, and some other
974 # NOTE: Squid can only determine the MAC/EUI address for IPv4
975 # clients that are on the same subnet. If the client is on a
976 # different subnet, then Squid cannot find out its address.
978 # NOTE 2: IPv6 protocol does not contain ARP. MAC/EUI is either
979 # encoded directly in the IPv6 address or not available.
981 acl aclname srcdomain .foo.com ...
982 # reverse lookup, from client IP [slow]
983 acl aclname dstdomain [-n] .foo.com ...
984 # Destination server from URL [fast]
985 acl aclname srcdom_regex [-i] \.foo\.com ...
986 # regex matching client name [slow]
987 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
988 # regex matching server [fast]
990 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
991 # based URL is used and no match is found. The name "none" is used
992 # if the reverse lookup fails.
994 acl aclname src_as number ...
995 acl aclname dst_as number ...
997 # Except for access control, AS numbers can be used for
998 # routing of requests to specific caches. Here's an
999 # example for routing all requests for AS#1241 and only
1000 # those to mycache.mydomain.net:
1001 # acl asexample dst_as 1241
1002 # cache_peer_access mycache.mydomain.net allow asexample
1003 # cache_peer_access mycache_mydomain.net deny all
1005 acl aclname peername myPeer ...
1007 # match against a named cache_peer entry
1008 # set unique name= on cache_peer lines for reliable use.
1010 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
1020 # h1:m1 must be less than h2:m2
1022 acl aclname url_regex [-i] ^http:// ...
1023 # regex matching on whole URL [fast]
1024 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
1025 # regex matching on URL login field
1026 acl aclname urlpath_regex [-i] \.gif$ ...
1027 # regex matching on URL path [fast]
1029 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
1031 acl aclname localport 3128 ... # TCP port the client connected to [fast]
1032 # NP: for interception mode this is usually '80'
1034 acl aclname myportname 3128 ... # *_port name [fast]
1036 acl aclname proto HTTP FTP ... # request protocol [fast]
1038 acl aclname method GET POST ... # HTTP request method [fast]
1040 acl aclname http_status 200 301 500- 400-403 ...
1041 # status code in reply [fast]
1043 acl aclname browser [-i] regexp ...
1044 # pattern match on User-Agent header (see also req_header below) [fast]
1046 acl aclname referer_regex [-i] regexp ...
1047 # pattern match on Referer header [fast]
1048 # Referer is highly unreliable, so use with care
1050 acl aclname ident username ...
1051 acl aclname ident_regex [-i] pattern ...
1052 # string match on ident output [slow]
1053 # use REQUIRED to accept any non-null ident.
1055 acl aclname proxy_auth [-i] username ...
1056 acl aclname proxy_auth_regex [-i] pattern ...
1057 # perform http authentication challenge to the client and match against
1058 # supplied credentials [slow]
1060 # takes a list of allowed usernames.
1061 # use REQUIRED to accept any valid username.
1063 # Will use proxy authentication in forward-proxy scenarios, and plain
1064 # http authenticaiton in reverse-proxy scenarios
1066 # NOTE: when a Proxy-Authentication header is sent but it is not
1067 # needed during ACL checking the username is NOT logged
1070 # NOTE: proxy_auth requires a EXTERNAL authentication program
1071 # to check username/password combinations (see
1072 # auth_param directive).
1074 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
1075 # as the browser needs to be configured for using a proxy in order
1076 # to respond to proxy authentication.
1078 acl aclname snmp_community string ...
1079 # A community string to limit access to your SNMP Agent [fast]
1082 # acl snmppublic snmp_community public
1084 acl aclname maxconn number
1085 # This will be matched when the client's IP address has
1086 # more than <number> TCP connections established. [fast]
1087 # NOTE: This only measures direct TCP links so X-Forwarded-For
1088 # indirect clients are not counted.
1090 acl aclname max_user_ip [-s] number
1091 # This will be matched when the user attempts to log in from more
1092 # than <number> different ip addresses. The authenticate_ip_ttl
1093 # parameter controls the timeout on the ip entries. [fast]
1094 # If -s is specified the limit is strict, denying browsing
1095 # from any further IP addresses until the ttl has expired. Without
1096 # -s Squid will just annoy the user by "randomly" denying requests.
1097 # (the counter is reset each time the limit is reached and a
1098 # request is denied)
1099 # NOTE: in acceleration mode or where there is mesh of child proxies,
1100 # clients may appear to come from multiple addresses if they are
1101 # going through proxy farms, so a limit of 1 may cause user problems.
1103 acl aclname random probability
1104 # Pseudo-randomly match requests. Based on the probability given.
1105 # Probability may be written as a decimal (0.333), fraction (1/3)
1106 # or ratio of matches:non-matches (3:5).
1108 acl aclname req_mime_type [-i] mime-type ...
1109 # regex match against the mime type of the request generated
1110 # by the client. Can be used to detect file upload or some
1111 # types HTTP tunneling requests [fast]
1112 # NOTE: This does NOT match the reply. You cannot use this
1113 # to match the returned file type.
1115 acl aclname req_header header-name [-i] any\.regex\.here
1116 # regex match against any of the known request headers. May be
1117 # thought of as a superset of "browser", "referer" and "mime-type"
1120 acl aclname rep_mime_type [-i] mime-type ...
1121 # regex match against the mime type of the reply received by
1122 # squid. Can be used to detect file download or some
1123 # types HTTP tunneling requests. [fast]
1124 # NOTE: This has no effect in http_access rules. It only has
1125 # effect in rules that affect the reply data stream such as
1126 # http_reply_access.
1128 acl aclname rep_header header-name [-i] any\.regex\.here
1129 # regex match against any of the known reply headers. May be
1130 # thought of as a superset of "browser", "referer" and "mime-type"
1133 acl aclname external class_name [arguments...]
1134 # external ACL lookup via a helper class defined by the
1135 # external_acl_type directive [slow]
1137 acl aclname user_cert attribute values...
1138 # match against attributes in a user SSL certificate
1139 # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
1141 acl aclname ca_cert attribute values...
1142 # match against attributes a users issuing CA SSL certificate
1143 # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
1145 acl aclname ext_user username ...
1146 acl aclname ext_user_regex [-i] pattern ...
1147 # string match on username returned by external acl helper [slow]
1148 # use REQUIRED to accept any non-null user name.
1150 acl aclname tag tagvalue ...
1151 # string match on tag returned by external acl helper [fast]
1152 # DEPRECATED. Only the first tag will match with this ACL.
1153 # Use the 'note' ACL instead for handling multiple tag values.
1155 acl aclname hier_code codename ...
1156 # string match against squid hierarchy code(s); [fast]
1157 # e.g., DIRECT, PARENT_HIT, NONE, etc.
1159 # NOTE: This has no effect in http_access rules. It only has
1160 # effect in rules that affect the reply data stream such as
1161 # http_reply_access.
1163 acl aclname note name [value ...]
1164 # match transaction annotation [fast]
1165 # Without values, matches any annotation with a given name.
1166 # With value(s), matches any annotation with a given name that
1167 # also has one of the given values.
1168 # Names and values are compared using a string equality test.
1169 # Annotation sources include note and adaptation_meta directives
1170 # as well as helper and eCAP responses.
1172 acl aclname adaptation_service service ...
1173 # Matches the name of any icap_service, ecap_service,
1174 # adaptation_service_set, or adaptation_service_chain that Squid
1175 # has used (or attempted to use) for the master transaction.
1176 # This ACL must be defined after the corresponding adaptation
1177 # service is named in squid.conf. This ACL is usable with
1178 # adaptation_meta because it starts matching immediately after
1179 # the service has been selected for adaptation.
1182 acl aclname ssl_error errorname
1183 # match against SSL certificate validation error [fast]
1185 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1188 # The following can be used as shortcuts for certificate properties:
1189 # [ssl::]certHasExpired: the "not after" field is in the past
1190 # [ssl::]certNotYetValid: the "not before" field is in the future
1191 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1192 # [ssl::]certSelfSigned: The certificate is self signed.
1193 # [ssl::]certDomainMismatch: The certificate CN domain does not
1194 # match the name the name of the host we are connecting to.
1196 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1197 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1198 # predefined ACLs, just like the 'all' ACL.
1200 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1201 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1203 acl aclname server_cert_fingerprint [-sha1] fingerprint
1204 # match against server SSL certificate fingerprint [fast]
1206 # The fingerprint is the digest of the DER encoded version
1207 # of the whole certificate. The user should use the form: XX:XX:...
1208 # Optional argument specifies the digest algorithm to use.
1209 # The SHA1 digest algorithm is the default and is currently
1210 # the only algorithm supported (-sha1).
1212 acl aclname at_step step
1213 # match against the current step during ssl_bump evaluation [fast]
1214 # Never matches and should not be used outside the ssl_bump context.
1216 # At each SslBump step, Squid evaluates ssl_bump directives to find
1217 # the next bumping action (e.g., peek or splice). Valid SslBump step
1218 # values and the corresponding ssl_bump evaluation moments are:
1219 # SslBump1: After getting TCP-level and HTTP CONNECT info.
1220 # SslBump2: After getting SSL Client Hello info.
1221 # SslBump3: After getting SSL Server Hello info.
1223 acl aclname ssl::server_name .foo.com ...
1224 # matches server name obtained from various sources [fast]
1226 # The server name is obtained during Ssl-Bump steps from such sources
1227 # as CONNECT request URI, client SNI, and SSL server certificate CN.
1228 # During each Ssl-Bump step, Squid may improve its understanding of a
1229 # "true server name". Unlike dstdomain, this ACL does not perform
1232 acl aclname ssl::server_name_regex [-i] \.foo\.com ...
1233 # regex matches server name obtained from various sources [fast]
1235 acl aclname any-of acl1 acl2 ...
1236 # match any one of the acls [fast or slow]
1237 # The first matching ACL stops further ACL evaluation.
1239 # ACLs from multiple any-of lines with the same name are ORed.
1240 # For example, A = (a1 or a2) or (a3 or a4) can be written as
1241 # acl A any-of a1 a2
1242 # acl A any-of a3 a4
1244 # This group ACL is fast if all evaluated ACLs in the group are fast
1245 # and slow otherwise.
1247 acl aclname all-of acl1 acl2 ...
1248 # match all of the acls [fast or slow]
1249 # The first mismatching ACL stops further ACL evaluation.
1251 # ACLs from multiple all-of lines with the same name are ORed.
1252 # For example, B = (b1 and b2) or (b3 and b4) can be written as
1253 # acl B all-of b1 b2
1254 # acl B all-of b3 b4
1256 # This group ACL is fast if all evaluated ACLs in the group are fast
1257 # and slow otherwise.
1260 acl macaddress arp 09:00:2b:23:45:67
1261 acl myexample dst_as 1241
1262 acl password proxy_auth REQUIRED
1263 acl fileupload req_mime_type -i ^multipart/form-data$
1264 acl javascript rep_mime_type -i ^application/x-javascript$
1268 # Recommended minimum configuration:
1271 # Example rule allowing access from your local networks.
1272 # Adapt to list your (internal) IP networks from where browsing
1274 acl localnet src 0.0.0.1-0.255.255.255 # RFC 1122 "this" network (LAN)
1275 acl localnet src 10.0.0.0/8 # RFC 1918 local private network (LAN)
1276 acl localnet src 100.64.0.0/10 # RFC 6598 shared address space (CGN)
1277 acl localhet src 169.254.0.0/16 # RFC 3927 link-local (directly plugged) machines
1278 acl localnet src 172.16.0.0/12 # RFC 1918 local private network (LAN)
1279 acl localnet src 192.168.0.0/16 # RFC 1918 local private network (LAN)
1280 acl localnet src fc00::/7 # RFC 4193 local private network range
1281 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1283 acl SSL_ports port 443
1284 acl Safe_ports port 80 # http
1285 acl Safe_ports port 21 # ftp
1286 acl Safe_ports port 443 # https
1287 acl Safe_ports port 70 # gopher
1288 acl Safe_ports port 210 # wais
1289 acl Safe_ports port 1025-65535 # unregistered ports
1290 acl Safe_ports port 280 # http-mgmt
1291 acl Safe_ports port 488 # gss-http
1292 acl Safe_ports port 591 # filemaker
1293 acl Safe_ports port 777 # multiling http
1294 acl CONNECT method CONNECT
1298 NAME: proxy_protocol_access
1300 LOC: Config.accessList.proxyProtocol
1302 DEFAULT_DOC: all TCP connections to ports with require-proxy-header will be denied
1304 Determine which client proxies can be trusted to provide correct
1305 information regarding real client IP address using PROXY protocol.
1307 Requests may pass through a chain of several other proxies
1308 before reaching us. The original source details may by sent in:
1309 * HTTP message Forwarded header, or
1310 * HTTP message X-Forwarded-For header, or
1311 * PROXY protocol connection header.
1313 This directive is solely for validating new PROXY protocol
1314 connections received from a port flagged with require-proxy-header.
1315 It is checked only once after TCP connection setup.
1317 A deny match results in TCP connection closure.
1319 An allow match is required for Squid to permit the corresponding
1320 TCP connection, before Squid even looks for HTTP request headers.
1321 If there is an allow match, Squid starts using PROXY header information
1322 to determine the source address of the connection for all future ACL
1323 checks, logging, etc.
1325 SECURITY CONSIDERATIONS:
1327 Any host from which we accept client IP details can place
1328 incorrect information in the relevant header, and Squid
1329 will use the incorrect information as if it were the
1330 source address of the request. This may enable remote
1331 hosts to bypass any access control restrictions that are
1332 based on the client's source addresses.
1334 This clause only supports fast acl types.
1335 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1338 NAME: follow_x_forwarded_for
1340 IFDEF: FOLLOW_X_FORWARDED_FOR
1341 LOC: Config.accessList.followXFF
1342 DEFAULT_IF_NONE: deny all
1343 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1345 Determine which client proxies can be trusted to provide correct
1346 information regarding real client IP address.
1348 Requests may pass through a chain of several other proxies
1349 before reaching us. The original source details may by sent in:
1350 * HTTP message Forwarded header, or
1351 * HTTP message X-Forwarded-For header, or
1352 * PROXY protocol connection header.
1354 PROXY protocol connections are controlled by the proxy_protocol_access
1355 directive which is checked before this.
1357 If a request reaches us from a source that is allowed by this
1358 directive, then we trust the information it provides regarding
1359 the IP of the client it received from (if any).
1361 For the purpose of ACLs used in this directive the src ACL type always
1362 matches the address we are testing and srcdomain matches its rDNS.
1364 On each HTTP request Squid checks for X-Forwarded-For header fields.
1365 If found the header values are iterated in reverse order and an allow
1366 match is required for Squid to continue on to the next value.
1367 The verification ends when a value receives a deny match, cannot be
1368 tested, or there are no more values to test.
1369 NOTE: Squid does not yet follow the Forwarded HTTP header.
1371 The end result of this process is an IP address that we will
1372 refer to as the indirect client address. This address may
1373 be treated as the client address for access control, ICAP, delay
1374 pools and logging, depending on the acl_uses_indirect_client,
1375 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1376 log_uses_indirect_client and tproxy_uses_indirect_client options.
1378 This clause only supports fast acl types.
1379 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1381 SECURITY CONSIDERATIONS:
1383 Any host from which we accept client IP details can place
1384 incorrect information in the relevant header, and Squid
1385 will use the incorrect information as if it were the
1386 source address of the request. This may enable remote
1387 hosts to bypass any access control restrictions that are
1388 based on the client's source addresses.
1392 acl localhost src 127.0.0.1
1393 acl my_other_proxy srcdomain .proxy.example.com
1394 follow_x_forwarded_for allow localhost
1395 follow_x_forwarded_for allow my_other_proxy
1398 NAME: acl_uses_indirect_client
1401 IFDEF: FOLLOW_X_FORWARDED_FOR
1403 LOC: Config.onoff.acl_uses_indirect_client
1405 Controls whether the indirect client address
1406 (see follow_x_forwarded_for) is used instead of the
1407 direct client address in acl matching.
1409 NOTE: maxconn ACL considers direct TCP links and indirect
1410 clients will always have zero. So no match.
1413 NAME: delay_pool_uses_indirect_client
1416 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1418 LOC: Config.onoff.delay_pool_uses_indirect_client
1420 Controls whether the indirect client address
1421 (see follow_x_forwarded_for) is used instead of the
1422 direct client address in delay pools.
1425 NAME: log_uses_indirect_client
1428 IFDEF: FOLLOW_X_FORWARDED_FOR
1430 LOC: Config.onoff.log_uses_indirect_client
1432 Controls whether the indirect client address
1433 (see follow_x_forwarded_for) is used instead of the
1434 direct client address in the access log.
1437 NAME: tproxy_uses_indirect_client
1440 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1442 LOC: Config.onoff.tproxy_uses_indirect_client
1444 Controls whether the indirect client address
1445 (see follow_x_forwarded_for) is used instead of the
1446 direct client address when spoofing the outgoing client.
1448 This has no effect on requests arriving in non-tproxy
1451 SECURITY WARNING: Usage of this option is dangerous
1452 and should not be used trivially. Correct configuration
1453 of follow_x_forwarded_for with a limited set of trusted
1454 sources is required to prevent abuse of your proxy.
1457 NAME: spoof_client_ip
1459 LOC: Config.accessList.spoof_client_ip
1461 DEFAULT_DOC: Allow spoofing on all TPROXY traffic.
1463 Control client IP address spoofing of TPROXY traffic based on
1464 defined access lists.
1466 spoof_client_ip allow|deny [!]aclname ...
1468 If there are no "spoof_client_ip" lines present, the default
1469 is to "allow" spoofing of any suitable request.
1471 Note that the cache_peer "no-tproxy" option overrides this ACL.
1473 This clause supports fast acl types.
1474 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1479 LOC: Config.accessList.http
1480 DEFAULT_IF_NONE: deny all
1481 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1483 Allowing or Denying access based on defined access lists
1485 To allow or deny a message received on an HTTP, HTTPS, or FTP port:
1486 http_access allow|deny [!]aclname ...
1488 NOTE on default values:
1490 If there are no "access" lines present, the default is to deny
1493 If none of the "access" lines cause a match, the default is the
1494 opposite of the last line in the list. If the last line was
1495 deny, the default is allow. Conversely, if the last line
1496 is allow, the default will be deny. For these reasons, it is a
1497 good idea to have an "deny all" entry at the end of your access
1498 lists to avoid potential confusion.
1500 This clause supports both fast and slow acl types.
1501 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1506 # Recommended minimum Access Permission configuration:
1508 # Deny requests to certain unsafe ports
1509 http_access deny !Safe_ports
1511 # Deny CONNECT to other than secure SSL ports
1512 http_access deny CONNECT !SSL_ports
1514 # Only allow cachemgr access from localhost
1515 http_access allow localhost manager
1516 http_access deny manager
1518 # We strongly recommend the following be uncommented to protect innocent
1519 # web applications running on the proxy server who think the only
1520 # one who can access services on "localhost" is a local user
1521 #http_access deny to_localhost
1524 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1527 # Example rule allowing access from your local networks.
1528 # Adapt localnet in the ACL section to list your (internal) IP networks
1529 # from where browsing should be allowed
1530 http_access allow localnet
1531 http_access allow localhost
1533 # And finally deny all other access to this proxy
1534 http_access deny all
1538 NAME: adapted_http_access http_access2
1540 LOC: Config.accessList.adapted_http
1542 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1544 Allowing or Denying access based on defined access lists
1546 Essentially identical to http_access, but runs after redirectors
1547 and ICAP/eCAP adaptation. Allowing access control based on their
1550 If not set then only http_access is used.
1553 NAME: http_reply_access
1555 LOC: Config.accessList.reply
1557 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1559 Allow replies to client requests. This is complementary to http_access.
1561 http_reply_access allow|deny [!] aclname ...
1563 NOTE: if there are no access lines present, the default is to allow
1566 If none of the access lines cause a match the opposite of the
1567 last line will apply. Thus it is good practice to end the rules
1568 with an "allow all" or "deny all" entry.
1570 This clause supports both fast and slow acl types.
1571 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1576 LOC: Config.accessList.icp
1578 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1580 Allowing or Denying access to the ICP port based on defined
1583 icp_access allow|deny [!]aclname ...
1585 NOTE: The default if no icp_access lines are present is to
1586 deny all traffic. This default may cause problems with peers
1589 This clause only supports fast acl types.
1590 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1592 # Allow ICP queries from local networks only
1593 #icp_access allow localnet
1594 #icp_access deny all
1600 LOC: Config.accessList.htcp
1602 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1604 Allowing or Denying access to the HTCP port based on defined
1607 htcp_access allow|deny [!]aclname ...
1609 See also htcp_clr_access for details on access control for
1610 cache purge (CLR) HTCP messages.
1612 NOTE: The default if no htcp_access lines are present is to
1613 deny all traffic. This default may cause problems with peers
1614 using the htcp option.
1616 This clause only supports fast acl types.
1617 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1619 # Allow HTCP queries from local networks only
1620 #htcp_access allow localnet
1621 #htcp_access deny all
1624 NAME: htcp_clr_access
1627 LOC: Config.accessList.htcp_clr
1629 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1631 Allowing or Denying access to purge content using HTCP based
1632 on defined access lists.
1633 See htcp_access for details on general HTCP access control.
1635 htcp_clr_access allow|deny [!]aclname ...
1637 This clause only supports fast acl types.
1638 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1640 # Allow HTCP CLR requests from trusted peers
1641 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1642 htcp_clr_access allow htcp_clr_peer
1643 htcp_clr_access deny all
1648 LOC: Config.accessList.miss
1650 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1652 Determines whether network access is permitted when satisfying a request.
1655 to force your neighbors to use you as a sibling instead of
1658 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1659 miss_access deny !localclients
1660 miss_access allow all
1662 This means only your local clients are allowed to fetch relayed/MISS
1663 replies from the network and all other clients can only fetch cached
1666 The default for this setting allows all clients who passed the
1667 http_access rules to relay via this proxy.
1669 This clause only supports fast acl types.
1670 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1673 NAME: ident_lookup_access
1677 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1678 LOC: Ident::TheConfig.identLookup
1680 A list of ACL elements which, if matched, cause an ident
1681 (RFC 931) lookup to be performed for this request. For
1682 example, you might choose to always perform ident lookups
1683 for your main multi-user Unix boxes, but not for your Macs
1684 and PCs. By default, ident lookups are not performed for
1687 To enable ident lookups for specific client addresses, you
1688 can follow this example:
1690 acl ident_aware_hosts src 198.168.1.0/24
1691 ident_lookup_access allow ident_aware_hosts
1692 ident_lookup_access deny all
1694 Only src type ACL checks are fully supported. A srcdomain
1695 ACL might work at times, but it will not always provide
1698 This clause only supports fast acl types.
1699 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1702 NAME: reply_body_max_size
1703 COMMENT: size [acl acl...]
1706 DEFAULT_DOC: No limit is applied.
1707 LOC: Config.ReplyBodySize
1709 This option specifies the maximum size of a reply body. It can be
1710 used to prevent users from downloading very large files, such as
1711 MP3's and movies. When the reply headers are received, the
1712 reply_body_max_size lines are processed, and the first line where
1713 all (if any) listed ACLs are true is used as the maximum body size
1716 This size is checked twice. First when we get the reply headers,
1717 we check the content-length value. If the content length value exists
1718 and is larger than the allowed size, the request is denied and the
1719 user receives an error message that says "the request or reply
1720 is too large." If there is no content-length, and the reply
1721 size exceeds this limit, the client's connection is just closed
1722 and they will receive a partial reply.
1724 WARNING: downstream caches probably can not detect a partial reply
1725 if there is no content-length header, so they will cache
1726 partial responses and give them out as hits. You should NOT
1727 use this option if you have downstream caches.
1729 WARNING: A maximum size smaller than the size of squid's error messages
1730 will cause an infinite loop and crash squid. Ensure that the smallest
1731 non-zero value you use is greater that the maximum header size plus
1732 the size of your largest error page.
1734 If you set this parameter none (the default), there will be
1737 Configuration Format is:
1738 reply_body_max_size SIZE UNITS [acl ...]
1740 reply_body_max_size 10 MB
1744 NAME: on_unsupported_protocol
1745 TYPE: on_unsupported_protocol
1746 LOC: Config.accessList.on_unsupported_protocol
1748 DEFAULT_DOC: Respond with an error message to unidentifiable traffic
1750 Determines Squid behavior when encountering strange requests at the
1751 beginning of an accepted TCP connection or the beginning of a bumped
1752 CONNECT tunnel. Controlling Squid reaction to unexpected traffic is
1753 especially useful in interception environments where Squid is likely
1754 to see connections for unsupported protocols that Squid should either
1755 terminate or tunnel at TCP level.
1757 on_unsupported_protocol <action> [!]acl ...
1759 The first matching action wins. Only fast ACLs are supported.
1761 Supported actions are:
1763 tunnel: Establish a TCP connection with the intended server and
1764 blindly shovel TCP packets between the client and server.
1766 respond: Respond with an error message, using the transfer protocol
1767 for the Squid port that received the request (e.g., HTTP
1768 for connections intercepted at the http_port). This is the
1771 Squid expects the following traffic patterns:
1773 http_port: a plain HTTP request
1774 https_port: SSL/TLS handshake followed by an [encrypted] HTTP request
1775 ftp_port: a plain FTP command (no on_unsupported_protocol support yet!)
1776 CONNECT tunnel on http_port: same as https_port
1777 CONNECT tunnel on https_port: same as https_port
1779 Currently, this directive has effect on intercepted connections and
1780 bumped tunnels only. Other cases are not supported because Squid
1781 cannot know the intended destination of other traffic.
1784 # define what Squid errors indicate receiving non-HTTP traffic:
1785 acl foreignProtocol squid_error ERR_PROTOCOL_UNKNOWN ERR_TOO_BIG
1786 # define what Squid errors indicate receiving nothing:
1787 acl serverTalksFirstProtocol squid_error ERR_REQUEST_START_TIMEOUT
1788 # tunnel everything that does not look like HTTP:
1789 on_unsupported_protocol tunnel foreignProtocol
1790 # tunnel if we think the client waits for the server to talk first:
1791 on_unsupported_protocol tunnel serverTalksFirstProtocol
1792 # in all other error cases, just send an HTTP "error page" response:
1793 on_unsupported_protocol respond all
1795 See also: squid_error ACL
1800 -----------------------------------------------------------------------------
1803 NAME: http_port ascii_port
1808 Usage: port [mode] [options]
1809 hostname:port [mode] [options]
1810 1.2.3.4:port [mode] [options]
1812 The socket addresses where Squid will listen for HTTP client
1813 requests. You may specify multiple socket addresses.
1814 There are three forms: port alone, hostname with port, and
1815 IP address with port. If you specify a hostname or IP
1816 address, Squid binds the socket to that specific
1817 address. Most likely, you do not need to bind to a specific
1818 address, so you can use the port number alone.
1820 If you are running Squid in accelerator mode, you
1821 probably want to listen on port 80 also, or instead.
1823 The -a command line option may be used to specify additional
1824 port(s) where Squid listens for proxy request. Such ports will
1825 be plain proxy ports with no options.
1827 You may specify multiple socket addresses on multiple lines.
1831 intercept Support for IP-Layer NAT interception delivering
1832 traffic to this Squid port.
1833 NP: disables authentication on the port.
1835 tproxy Support Linux TPROXY (or BSD divert-to) with spoofing
1836 of outgoing connections using the client IP address.
1837 NP: disables authentication on the port.
1839 accel Accelerator / reverse proxy mode
1841 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1842 establish secure connection with the client and with
1843 the server, decrypt HTTPS messages as they pass through
1844 Squid, and treat them as unencrypted HTTP messages,
1845 becoming the man-in-the-middle.
1847 The ssl_bump option is required to fully enable
1848 bumping of CONNECT requests.
1850 Omitting the mode flag causes default forward proxy mode to be used.
1853 Accelerator Mode Options:
1855 defaultsite=domainname
1856 What to use for the Host: header if it is not present
1857 in a request. Determines what site (not origin server)
1858 accelerators should consider the default.
1860 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1862 protocol= Protocol to reconstruct accelerated and intercepted
1863 requests with. Defaults to HTTP/1.1 for http_port and
1864 HTTPS/1.1 for https_port.
1865 When an unsupported value is configured Squid will
1866 produce a FATAL error.
1867 Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
1869 vport Virtual host port support. Using the http_port number
1870 instead of the port passed on Host: headers.
1872 vport=NN Virtual host port support. Using the specified port
1873 number instead of the port passed on Host: headers.
1876 Act as if this Squid is the origin server.
1877 This currently means generate new Date: and Expires:
1878 headers on HIT instead of adding Age:.
1880 ignore-cc Ignore request Cache-Control headers.
1882 WARNING: This option violates HTTP specifications if
1883 used in non-accelerator setups.
1885 allow-direct Allow direct forwarding in accelerator mode. Normally
1886 accelerated requests are denied direct forwarding as if
1887 never_direct was used.
1889 WARNING: this option opens accelerator mode to security
1890 vulnerabilities usually only affecting in interception
1891 mode. Make sure to protect forwarding with suitable
1892 http_access rules when using this.
1895 SSL Bump Mode Options:
1896 In addition to these options ssl-bump requires TLS/SSL options.
1898 generate-host-certificates[=<on|off>]
1899 Dynamically create SSL server certificates for the
1900 destination hosts of bumped CONNECT requests.When
1901 enabled, the cert and key options are used to sign
1902 generated certificates. Otherwise generated
1903 certificate will be selfsigned.
1904 If there is a CA certificate lifetime of the generated
1905 certificate equals lifetime of the CA certificate. If
1906 generated certificate is selfsigned lifetime is three
1908 This option is enabled by default when ssl-bump is used.
1909 See the ssl-bump option above for more information.
1911 dynamic_cert_mem_cache_size=SIZE
1912 Approximate total RAM size spent on cached generated
1913 certificates. If set to zero, caching is disabled. The
1914 default value is 4MB.
1918 cert= Path to SSL certificate (PEM format).
1920 key= Path to SSL private key file (PEM format)
1921 if not specified, the certificate file is
1922 assumed to be a combined certificate and
1925 cipher= Colon separated list of supported ciphers.
1926 NOTE: some ciphers such as EDH ciphers depend on
1927 additional settings. If those settings are
1928 omitted the ciphers may be silently ignored
1929 by the OpenSSL library.
1931 options= Various SSL implementation options. The most important
1934 NO_SSLv3 Disallow the use of SSLv3
1936 NO_TLSv1 Disallow the use of TLSv1.0
1938 NO_TLSv1_1 Disallow the use of TLSv1.1
1940 NO_TLSv1_2 Disallow the use of TLSv1.2
1943 Always create a new key when using
1944 temporary/ephemeral DH key exchanges
1947 Enable ephemeral ECDH key exchange.
1948 The adopted curve should be specified
1949 using the tls-dh option.
1952 Disable use of RFC5077 session tickets.
1953 Some servers may have problems
1954 understanding the TLS extension due
1955 to ambiguous specification in RFC4507.
1957 ALL Enable various bug workarounds
1958 suggested as "harmless" by OpenSSL
1959 Be warned that this reduces SSL/TLS
1960 strength to some attacks.
1962 See the OpenSSL SSL_CTX_set_options documentation for a
1965 clientca= File containing the list of CAs to use when
1966 requesting a client certificate.
1968 tls-cafile= PEM file containing CA certificates to use when verifying
1969 client certificates. If not configured clientca will be
1970 used. May be repeated to load multiple files.
1972 capath= Directory containing additional CA certificates
1973 and CRL lists to use when verifying client certificates.
1974 Requires OpenSSL or LibreSSL.
1976 crlfile= File of additional CRL lists to use when verifying
1977 the client certificate, in addition to CRLs stored in
1978 the capath. Implies VERIFY_CRL flag below.
1981 File containing DH parameters for temporary/ephemeral DH key
1982 exchanges, optionally prefixed by a curve for ephemeral ECDH
1984 See OpenSSL documentation for details on how to create the
1985 DH parameter file. Supported curves for ECDH can be listed
1986 using the "openssl ecparam -list_curves" command.
1987 WARNING: EDH and EECDH ciphers will be silently disabled if
1988 this option is not set.
1990 sslflags= Various flags modifying the use of SSL:
1992 Don't request client certificates
1993 immediately, but wait until acl processing
1994 requires a certificate (not yet implemented).
1996 Don't allow for session reuse. Each connection
1997 will result in a new SSL session.
1999 Verify CRL lists when accepting client
2002 Verify CRL lists for all certificates in the
2003 client certificate chain.
2006 Do not use the system default Trusted CA.
2008 sslcontext= SSL session ID context identifier.
2012 connection-auth[=on|off]
2013 use connection-auth=off to tell Squid to prevent
2014 forwarding Microsoft connection oriented authentication
2015 (NTLM, Negotiate and Kerberos)
2017 disable-pmtu-discovery=
2018 Control Path-MTU discovery usage:
2019 off lets OS decide on what to do (default).
2020 transparent disable PMTU discovery when transparent
2022 always disable always PMTU discovery.
2024 In many setups of transparently intercepting proxies
2025 Path-MTU discovery can not work on traffic towards the
2026 clients. This is the case when the intercepting device
2027 does not fully track connections and fails to forward
2028 ICMP must fragment messages to the cache server. If you
2029 have such setup and experience that certain clients
2030 sporadically hang or never complete requests set
2031 disable-pmtu-discovery option to 'transparent'.
2033 name= Specifies a internal name for the port. Defaults to
2034 the port specification (port or addr:port)
2036 tcpkeepalive[=idle,interval,timeout]
2037 Enable TCP keepalive probes of idle connections.
2038 In seconds; idle is the initial time before TCP starts
2039 probing the connection, interval how often to probe, and
2040 timeout the time before giving up.
2042 require-proxy-header
2043 Require PROXY protocol version 1 or 2 connections.
2044 The proxy_protocol_access is required to whitelist
2045 downstream proxies which can be trusted.
2047 If you run Squid on a dual-homed machine with an internal
2048 and an external interface we recommend you to specify the
2049 internal address:port in http_port. This way Squid will only be
2050 visible on the internal address.
2054 # Squid normally listens to port 3128
2055 http_port @DEFAULT_HTTP_PORT@
2065 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
2067 The socket address where Squid will listen for client requests made
2068 over TLS or SSL connections. Commonly referred to as HTTPS.
2070 This is most useful for situations where you are running squid in
2071 accelerator mode and you want to do the SSL work at the accelerator level.
2073 You may specify multiple socket addresses on multiple lines,
2074 each with their own SSL certificate and/or options.
2078 accel Accelerator / reverse proxy mode
2080 intercept Support for IP-Layer interception of
2081 outgoing requests without browser settings.
2082 NP: disables authentication and IPv6 on the port.
2084 tproxy Support Linux TPROXY for spoofing outgoing
2085 connections using the client IP address.
2086 NP: disables authentication and maybe IPv6 on the port.
2088 ssl-bump For each intercepted connection allowed by ssl_bump
2089 ACLs, establish a secure connection with the client and with
2090 the server, decrypt HTTPS messages as they pass through
2091 Squid, and treat them as unencrypted HTTP messages,
2092 becoming the man-in-the-middle.
2094 An "ssl_bump server-first" match is required to
2095 fully enable bumping of intercepted SSL connections.
2097 Requires tproxy or intercept.
2099 Omitting the mode flag causes default forward proxy mode to be used.
2102 See http_port for a list of generic options
2107 cert= Path to SSL certificate (PEM format).
2109 key= Path to SSL private key file (PEM format)
2110 if not specified, the certificate file is
2111 assumed to be a combined certificate and
2114 cipher= Colon separated list of supported ciphers.
2116 options= Various SSL engine options. The most important
2119 NO_SSLv3 Disallow the use of SSLv3
2121 NO_TLSv1 Disallow the use of TLSv1.0
2123 NO_TLSv1_1 Disallow the use of TLSv1.1
2125 NO_TLSv1_2 Disallow the use of TLSv1.2
2128 Always create a new key when using
2129 temporary/ephemeral DH key exchanges
2132 Enable ephemeral ECDH key exchange.
2133 The adopted curve should be specified
2134 using the tls-dh option.
2137 Disable use of RFC5077 session tickets.
2138 Some servers may have problems
2139 understanding the TLS extension due
2140 to ambiguous specification in RFC4507.
2142 ALL Enable various bug workarounds
2143 suggested as "harmless" by OpenSSL
2144 Be warned that this reduces SSL/TLS
2145 strength to some attacks.
2147 See the OpenSSL SSL_CTX_set_options documentation for a
2150 clientca= File containing the list of CAs to use when
2151 requesting a client certificate.
2153 tls-cafile= PEM file containing CA certificates to use when verifying
2154 client certificates. If not configured clientca will be
2155 used. May be repeated to load multiple files.
2157 capath= Directory containing additional CA certificates
2158 and CRL lists to use when verifying client certificates.
2159 Requires OpenSSL or LibreSSL.
2161 crlfile= File of additional CRL lists to use when verifying
2162 the client certificate, in addition to CRLs stored in
2163 the capath. Implies VERIFY_CRL flag below.
2166 File containing DH parameters for temporary/ephemeral DH key
2167 exchanges, optionally prefixed by a curve for ephemeral ECDH
2170 sslflags= Various flags modifying the use of SSL:
2172 Don't request client certificates
2173 immediately, but wait until acl processing
2174 requires a certificate (not yet implemented).
2176 Don't allow for session reuse. Each connection
2177 will result in a new SSL session.
2179 Verify CRL lists when accepting client
2182 Verify CRL lists for all certificates in the
2183 client certificate chain.
2186 Do not use the system default Trusted CA.
2188 sslcontext= SSL session ID context identifier.
2190 generate-host-certificates[=<on|off>]
2191 Dynamically create SSL server certificates for the
2192 destination hosts of bumped SSL requests.When
2193 enabled, the cert and key options are used to sign
2194 generated certificates. Otherwise generated
2195 certificate will be selfsigned.
2196 If there is CA certificate life time of generated
2197 certificate equals lifetime of CA certificate. If
2198 generated certificate is selfsigned lifetime is three
2200 This option is enabled by default when SslBump is used.
2201 See the sslBump option above for more information.
2203 dynamic_cert_mem_cache_size=SIZE
2204 Approximate total RAM size spent on cached generated
2205 certificates. If set to zero, caching is disabled. The
2206 default value is 4MB.
2208 See http_port for a list of available options.
2216 Enables Native FTP proxy by specifying the socket address where Squid
2217 listens for FTP client requests. See http_port directive for various
2218 ways to specify the listening address and mode.
2220 Usage: ftp_port address [mode] [options]
2222 WARNING: This is a new, experimental, complex feature that has seen
2223 limited production exposure. Some Squid modules (e.g., caching) do not
2224 currently work with native FTP proxying, and many features have not
2225 even been tested for compatibility. Test well before deploying!
2227 Native FTP proxying differs substantially from proxying HTTP requests
2228 with ftp:// URIs because Squid works as an FTP server and receives
2229 actual FTP commands (rather than HTTP requests with FTP URLs).
2231 Native FTP commands accepted at ftp_port are internally converted or
2232 wrapped into HTTP-like messages. The same happens to Native FTP
2233 responses received from FTP origin servers. Those HTTP-like messages
2234 are shoveled through regular access control and adaptation layers
2235 between the FTP client and the FTP origin server. This allows Squid to
2236 examine, adapt, block, and log FTP exchanges. Squid reuses most HTTP
2237 mechanisms when shoveling wrapped FTP messages. For example,
2238 http_access and adaptation_access directives are used.
2242 intercept Same as http_port intercept. The FTP origin address is
2243 determined based on the intended destination of the
2244 intercepted connection.
2246 tproxy Support Linux TPROXY for spoofing outgoing
2247 connections using the client IP address.
2248 NP: disables authentication and maybe IPv6 on the port.
2250 By default (i.e., without an explicit mode option), Squid extracts the
2251 FTP origin address from the login@origin parameter of the FTP USER
2252 command. Many popular FTP clients support such native FTP proxying.
2256 name=token Specifies an internal name for the port. Defaults to
2257 the port address. Usable with myportname ACL.
2260 Enables tracking of FTP directories by injecting extra
2261 PWD commands and adjusting Request-URI (in wrapping
2262 HTTP requests) to reflect the current FTP server
2263 directory. Tracking is disabled by default.
2265 protocol=FTP Protocol to reconstruct accelerated and intercepted
2266 requests with. Defaults to FTP. No other accepted
2267 values have been tested with. An unsupported value
2268 results in a FATAL error. Accepted values are FTP,
2269 HTTP (or HTTP/1.1), and HTTPS (or HTTPS/1.1).
2271 Other http_port modes and options that are not specific to HTTP and
2272 HTTPS may also work.
2275 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
2278 LOC: Ip::Qos::TheConfig.tosToServer
2280 Allows you to select a TOS/Diffserv value for packets outgoing
2281 on the server side, based on an ACL.
2283 tcp_outgoing_tos ds-field [!]aclname ...
2285 Example where normal_service_net uses the TOS value 0x00
2286 and good_service_net uses 0x20
2288 acl normal_service_net src 10.0.0.0/24
2289 acl good_service_net src 10.0.1.0/24
2290 tcp_outgoing_tos 0x00 normal_service_net
2291 tcp_outgoing_tos 0x20 good_service_net
2293 TOS/DSCP values really only have local significance - so you should
2294 know what you're specifying. For more information, see RFC2474,
2295 RFC2475, and RFC3260.
2297 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2298 "default" to use whatever default your host has.
2299 Note that only multiples of 4 are usable as the two rightmost bits have
2300 been redefined for use by ECN (RFC 3168 section 23.1).
2301 The squid parser will enforce this by masking away the ECN bits.
2303 Processing proceeds in the order specified, and stops at first fully
2306 Only fast ACLs are supported.
2309 NAME: clientside_tos
2312 LOC: Ip::Qos::TheConfig.tosToClient
2314 Allows you to select a TOS/DSCP value for packets being transmitted
2315 on the client-side, based on an ACL.
2317 clientside_tos ds-field [!]aclname ...
2319 Example where normal_service_net uses the TOS value 0x00
2320 and good_service_net uses 0x20
2322 acl normal_service_net src 10.0.0.0/24
2323 acl good_service_net src 10.0.1.0/24
2324 clientside_tos 0x00 normal_service_net
2325 clientside_tos 0x20 good_service_net
2327 Note: This feature is incompatible with qos_flows. Any TOS values set here
2328 will be overwritten by TOS values in qos_flows.
2330 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2331 "default" to use whatever default your host has.
2332 Note that only multiples of 4 are usable as the two rightmost bits have
2333 been redefined for use by ECN (RFC 3168 section 23.1).
2334 The squid parser will enforce this by masking away the ECN bits.
2338 NAME: tcp_outgoing_mark
2340 IFDEF: SO_MARK&&USE_LIBCAP
2342 LOC: Ip::Qos::TheConfig.nfmarkToServer
2344 Allows you to apply a Netfilter mark value to outgoing packets
2345 on the server side, based on an ACL.
2347 tcp_outgoing_mark mark-value [!]aclname ...
2349 Example where normal_service_net uses the mark value 0x00
2350 and good_service_net uses 0x20
2352 acl normal_service_net src 10.0.0.0/24
2353 acl good_service_net src 10.0.1.0/24
2354 tcp_outgoing_mark 0x00 normal_service_net
2355 tcp_outgoing_mark 0x20 good_service_net
2357 Only fast ACLs are supported.
2360 NAME: clientside_mark
2362 IFDEF: SO_MARK&&USE_LIBCAP
2364 LOC: Ip::Qos::TheConfig.nfmarkToClient
2366 Allows you to apply a Netfilter mark value to packets being transmitted
2367 on the client-side, based on an ACL.
2369 clientside_mark mark-value [!]aclname ...
2371 Example where normal_service_net uses the mark value 0x00
2372 and good_service_net uses 0x20
2374 acl normal_service_net src 10.0.0.0/24
2375 acl good_service_net src 10.0.1.0/24
2376 clientside_mark 0x00 normal_service_net
2377 clientside_mark 0x20 good_service_net
2379 Note: This feature is incompatible with qos_flows. Any mark values set here
2380 will be overwritten by mark values in qos_flows.
2387 LOC: Ip::Qos::TheConfig
2389 Allows you to select a TOS/DSCP value to mark outgoing
2390 connections to the client, based on where the reply was sourced.
2391 For platforms using netfilter, allows you to set a netfilter mark
2392 value instead of, or in addition to, a TOS value.
2394 By default this functionality is disabled. To enable it with the default
2395 settings simply use "qos_flows mark" or "qos_flows tos". Default
2396 settings will result in the netfilter mark or TOS value being copied
2397 from the upstream connection to the client. Note that it is the connection
2398 CONNMARK value not the packet MARK value that is copied.
2400 It is not currently possible to copy the mark or TOS value from the
2401 client to the upstream connection request.
2403 TOS values really only have local significance - so you should
2404 know what you're specifying. For more information, see RFC2474,
2405 RFC2475, and RFC3260.
2407 The TOS/DSCP byte must be exactly that - a octet value 0 - 255.
2408 Note that only multiples of 4 are usable as the two rightmost bits have
2409 been redefined for use by ECN (RFC 3168 section 23.1).
2410 The squid parser will enforce this by masking away the ECN bits.
2412 Mark values can be any unsigned 32-bit integer value.
2414 This setting is configured by setting the following values:
2416 tos|mark Whether to set TOS or netfilter mark values
2418 local-hit=0xFF Value to mark local cache hits.
2420 sibling-hit=0xFF Value to mark hits from sibling peers.
2422 parent-hit=0xFF Value to mark hits from parent peers.
2424 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2425 over the preserve-miss feature (see below), unless
2426 mask is specified, in which case only the bits
2427 specified in the mask are written.
2429 The TOS variant of the following features are only possible on Linux
2430 and require your kernel to be patched with the TOS preserving ZPH
2431 patch, available from http://zph.bratcheda.org
2432 No patch is needed to preserve the netfilter mark, which will work
2433 with all variants of netfilter.
2435 disable-preserve-miss
2436 This option disables the preservation of the TOS or netfilter
2437 mark. By default, the existing TOS or netfilter mark value of
2438 the response coming from the remote server will be retained
2439 and masked with miss-mark.
2440 NOTE: in the case of a netfilter mark, the mark must be set on
2441 the connection (using the CONNMARK target) not on the packet
2445 Allows you to mask certain bits in the TOS or mark value
2446 received from the remote server, before copying the value to
2447 the TOS sent towards clients.
2448 Default for tos: 0xFF (TOS from server is not changed).
2449 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2451 All of these features require the --enable-zph-qos compilation flag
2452 (enabled by default). Netfilter marking also requires the
2453 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2454 libcap 2.09+ (--with-libcap).
2458 NAME: tcp_outgoing_address
2461 DEFAULT_DOC: Address selection is performed by the operating system.
2462 LOC: Config.accessList.outgoing_address
2464 Allows you to map requests to different outgoing IP addresses
2465 based on the username or source address of the user making
2468 tcp_outgoing_address ipaddr [[!]aclname] ...
2471 Forwarding clients with dedicated IPs for certain subnets.
2473 acl normal_service_net src 10.0.0.0/24
2474 acl good_service_net src 10.0.2.0/24
2476 tcp_outgoing_address 2001:db8::c001 good_service_net
2477 tcp_outgoing_address 10.1.0.2 good_service_net
2479 tcp_outgoing_address 2001:db8::beef normal_service_net
2480 tcp_outgoing_address 10.1.0.1 normal_service_net
2482 tcp_outgoing_address 2001:db8::1
2483 tcp_outgoing_address 10.1.0.3
2485 Processing proceeds in the order specified, and stops at first fully
2488 Squid will add an implicit IP version test to each line.
2489 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2490 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2493 NOTE: The use of this directive using client dependent ACLs is
2494 incompatible with the use of server side persistent connections. To
2495 ensure correct results it is best to set server_persistent_connections
2496 to off when using this directive in such configurations.
2498 NOTE: The use of this directive to set a local IP on outgoing TCP links
2499 is incompatible with using TPROXY to set client IP out outbound TCP links.
2500 When needing to contact peers use the no-tproxy cache_peer option and the
2501 client_dst_passthru directive re-enable normal forwarding such as this.
2505 NAME: host_verify_strict
2508 LOC: Config.onoff.hostStrictVerify
2510 Regardless of this option setting, when dealing with intercepted
2511 traffic, Squid always verifies that the destination IP address matches
2512 the Host header domain or IP (called 'authority form URL').
2514 This enforcement is performed to satisfy a MUST-level requirement in
2515 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2516 authority of the origin server or gateway given by the original URL".
2519 Squid always responds with an HTTP 409 (Conflict) error
2520 page and logs a security warning if there is no match.
2522 Squid verifies that the destination IP address matches
2523 the Host header for forward-proxy and reverse-proxy traffic
2524 as well. For those traffic types, Squid also enables the
2525 following checks, comparing the corresponding Host header
2526 and Request-URI components:
2528 * The host names (domain or IP) must be identical,
2529 but valueless or missing Host header disables all checks.
2530 For the two host names to match, both must be either IP
2533 * Port numbers must be identical, but if a port is missing
2534 the scheme-default port is assumed.
2537 When set to OFF (the default):
2538 Squid allows suspicious requests to continue but logs a
2539 security warning and blocks caching of the response.
2541 * Forward-proxy traffic is not checked at all.
2543 * Reverse-proxy traffic is not checked at all.
2545 * Intercepted traffic which passes verification is handled
2546 according to client_dst_passthru.
2548 * Intercepted requests which fail verification are sent
2549 to the client original destination instead of DIRECT.
2550 This overrides 'client_dst_passthru off'.
2552 For now suspicious intercepted CONNECT requests are always
2553 responded to with an HTTP 409 (Conflict) error page.
2558 As described in CVE-2009-0801 when the Host: header alone is used
2559 to determine the destination of a request it becomes trivial for
2560 malicious scripts on remote websites to bypass browser same-origin
2561 security policy and sandboxing protections.
2563 The cause of this is that such applets are allowed to perform their
2564 own HTTP stack, in which case the same-origin policy of the browser
2565 sandbox only verifies that the applet tries to contact the same IP
2566 as from where it was loaded at the IP level. The Host: header may
2567 be different from the connected IP and approved origin.
2571 NAME: client_dst_passthru
2574 LOC: Config.onoff.client_dst_passthru
2576 With NAT or TPROXY intercepted traffic Squid may pass the request
2577 directly to the original client destination IP or seek a faster
2578 source using the HTTP Host header.
2580 Using Host to locate alternative servers can provide faster
2581 connectivity with a range of failure recovery options.
2582 But can also lead to connectivity trouble when the client and
2583 server are attempting stateful interactions unaware of the proxy.
2585 This option (on by default) prevents alternative DNS entries being
2586 located to send intercepted traffic DIRECT to an origin server.
2587 The clients original destination IP and port will be used instead.
2589 Regardless of this option setting, when dealing with intercepted
2590 traffic Squid will verify the Host: header and any traffic which
2591 fails Host verification will be treated as if this option were ON.
2593 see host_verify_strict for details on the verification process.
2598 -----------------------------------------------------------------------------
2601 NAME: tls_outgoing_options
2602 IFDEF: USE_GNUTLS||USE_OPENSSL
2603 TYPE: securePeerOptions
2604 DEFAULT: min-version=1.0
2605 LOC: Security::ProxyOutgoingConfig
2607 disable Do not support https:// URLs.
2609 cert=/path/to/client/certificate
2610 A client TLS certificate to use when connecting.
2612 key=/path/to/client/private_key
2613 The private TLS key corresponding to the cert= above.
2614 If key= is not specified cert= is assumed to reference
2615 a PEM file containing both the certificate and the key.
2617 cipher=... The list of valid TLS ciphers to use.
2620 The minimum TLS protocol version to permit.
2621 To control SSLv3 use the options= parameter.
2622 Supported Values: 1.0 (default), 1.1, 1.2
2624 options=... Specify various TLS/SSL implementation options:
2626 NO_SSLv3 Disallow the use of SSLv3
2628 NO_TLSv1 Disallow the use of TLSv1.0
2630 NO_TLSv1_1 Disallow the use of TLSv1.1
2632 NO_TLSv1_2 Disallow the use of TLSv1.2
2635 Always create a new key when using
2636 temporary/ephemeral DH key exchanges
2639 Disable use of RFC5077 session tickets.
2640 Some servers may have problems
2641 understanding the TLS extension due
2642 to ambiguous specification in RFC4507.
2644 ALL Enable various bug workarounds
2645 suggested as "harmless" by OpenSSL
2646 Be warned that this reduces SSL/TLS
2647 strength to some attacks.
2649 See the OpenSSL SSL_CTX_set_options documentation for a
2652 cafile= PEM file containing CA certificates to use when verifying
2653 the peer certificate. May be repeated to load multiple files.
2655 capath= A directory containing additional CA certificates to
2656 use when verifying the peer certificate.
2657 Requires OpenSSL or LibreSSL.
2659 crlfile=... A certificate revocation list file to use when
2660 verifying the peer certificate.
2662 flags=... Specify various flags modifying the TLS implementation:
2665 Accept certificates even if they fail to
2668 Don't verify the peer certificate
2669 matches the server name
2671 no-default-ca Do not use the system default Trusted CA.
2673 domain= The peer name as advertised in its certificate.
2674 Used for verifying the correctness of the received peer
2675 certificate. If not specified the peer hostname will be
2681 -----------------------------------------------------------------------------
2684 NAME: ssl_unclean_shutdown
2688 LOC: Config.SSL.unclean_shutdown
2690 Some browsers (especially MSIE) bugs out on SSL shutdown
2697 LOC: Config.SSL.ssl_engine
2700 The OpenSSL engine to use. You will need to set this if you
2701 would like to use hardware SSL acceleration for example.
2704 NAME: sslproxy_session_ttl
2707 LOC: Config.SSL.session_ttl
2710 Sets the timeout value for SSL sessions
2713 NAME: sslproxy_session_cache_size
2716 LOC: Config.SSL.sessionCacheSize
2719 Sets the cache size to use for ssl session
2722 NAME: sslproxy_cert_sign_hash
2725 LOC: Config.SSL.certSignHash
2728 Sets the hashing algorithm to use when signing generated certificates.
2729 Valid algorithm names depend on the OpenSSL library used. The following
2730 names are usually available: sha1, sha256, sha512, and md5. Please see
2731 your OpenSSL library manual for the available hashes. By default, Squids
2732 that support this option use sha256 hashes.
2734 Squid does not forcefully purge cached certificates that were generated
2735 with an algorithm other than the currently configured one. They remain
2736 in the cache, subject to the regular cache eviction policy, and become
2737 useful if the algorithm changes again.
2742 TYPE: sslproxy_ssl_bump
2743 LOC: Config.accessList.ssl_bump
2744 DEFAULT_DOC: Become a TCP tunnel without decrypting proxied traffic.
2747 This option is consulted when a CONNECT request is received on
2748 an http_port (or a new connection is intercepted at an
2749 https_port), provided that port was configured with an ssl-bump
2750 flag. The subsequent data on the connection is either treated as
2751 HTTPS and decrypted OR tunneled at TCP level without decryption,
2752 depending on the first matching bumping "action".
2754 ssl_bump <action> [!]acl ...
2756 The following bumping actions are currently supported:
2759 Become a TCP tunnel without decrypting proxied traffic.
2760 This is the default action.
2763 Establish a secure connection with the server and, using a
2764 mimicked server certificate, with the client.
2767 Receive client (step SslBump1) or server (step SslBump2)
2768 certificate while preserving the possibility of splicing the
2769 connection. Peeking at the server certificate (during step 2)
2770 usually precludes bumping of the connection at step 3.
2773 Receive client (step SslBump1) or server (step SslBump2)
2774 certificate while preserving the possibility of bumping the
2775 connection. Staring at the server certificate (during step 2)
2776 usually precludes splicing of the connection at step 3.
2779 Close client and server connections.
2781 Backward compatibility actions available at step SslBump1:
2784 Bump the connection. Establish a secure connection with the
2785 client first, then connect to the server. This old mode does
2786 not allow Squid to mimic server SSL certificate and does not
2787 work with intercepted SSL connections.
2790 Bump the connection. Establish a secure connection with the
2791 server first, then establish a secure connection with the
2792 client, using a mimicked server certificate. Works with both
2793 CONNECT requests and intercepted SSL connections, but does
2794 not allow to make decisions based on SSL handshake info.
2797 Decide whether to bump or splice the connection based on
2798 client-to-squid and server-to-squid SSL hello messages.
2802 Same as the "splice" action.
2804 All ssl_bump rules are evaluated at each of the supported bumping
2805 steps. Rules with actions that are impossible at the current step are
2806 ignored. The first matching ssl_bump action wins and is applied at the
2807 end of the current step. If no rules match, the splice action is used.
2808 See the at_step ACL for a list of the supported SslBump steps.
2810 This clause supports both fast and slow acl types.
2811 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2813 See also: http_port ssl-bump, https_port ssl-bump, and acl at_step.
2816 # Example: Bump all requests except those originating from
2817 # localhost or those going to example.com.
2819 acl broken_sites dstdomain .example.com
2820 ssl_bump splice localhost
2821 ssl_bump splice broken_sites
2825 NAME: sslproxy_cert_error
2828 DEFAULT_DOC: Server certificate errors terminate the transaction.
2829 LOC: Config.ssl_client.cert_error
2832 Use this ACL to bypass server certificate validation errors.
2834 For example, the following lines will bypass all validation errors
2835 when talking to servers for example.com. All other
2836 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2838 acl BrokenButTrustedServers dstdomain example.com
2839 sslproxy_cert_error allow BrokenButTrustedServers
2840 sslproxy_cert_error deny all
2842 This clause only supports fast acl types.
2843 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2844 Using slow acl types may result in server crashes
2846 Without this option, all server certificate validation errors
2847 terminate the transaction to protect Squid and the client.
2849 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2850 but should not happen unless your OpenSSL library is buggy.
2853 Bypassing validation errors is dangerous because an
2854 error usually implies that the server cannot be trusted
2855 and the connection may be insecure.
2857 See also: sslproxy_flags and DONT_VERIFY_PEER.
2860 NAME: sslproxy_cert_sign
2863 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2864 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2865 POSTSCRIPTUM: signTrusted all
2866 TYPE: sslproxy_cert_sign
2867 LOC: Config.ssl_client.cert_sign
2870 sslproxy_cert_sign <signing algorithm> acl ...
2872 The following certificate signing algorithms are supported:
2875 Sign using the configured CA certificate which is usually
2876 placed in and trusted by end-user browsers. This is the
2877 default for trusted origin server certificates.
2880 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2881 This is the default for untrusted origin server certificates
2882 that are not self-signed (see ssl::certUntrusted).
2885 Sign using a self-signed certificate with the right CN to
2886 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2887 browser. This is the default for self-signed origin server
2888 certificates (see ssl::certSelfSigned).
2890 This clause only supports fast acl types.
2892 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2893 signing algorithm to generate the certificate and ignores all
2894 subsequent sslproxy_cert_sign options (the first match wins). If no
2895 acl(s) match, the default signing algorithm is determined by errors
2896 detected when obtaining and validating the origin server certificate.
2898 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2899 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2900 CONNECT request that carries a domain name. In all other cases (CONNECT
2901 to an IP address or an intercepted SSL connection), Squid cannot detect
2902 the domain mismatch at certificate generation time when
2903 bump-server-first is used.
2906 NAME: sslproxy_cert_adapt
2909 TYPE: sslproxy_cert_adapt
2910 LOC: Config.ssl_client.cert_adapt
2913 sslproxy_cert_adapt <adaptation algorithm> acl ...
2915 The following certificate adaptation algorithms are supported:
2918 Sets the "Not After" property to the "Not After" property of
2919 the CA certificate used to sign generated certificates.
2922 Sets the "Not Before" property to the "Not Before" property of
2923 the CA certificate used to sign generated certificates.
2925 setCommonName or setCommonName{CN}
2926 Sets Subject.CN property to the host name specified as a
2927 CN parameter or, if no explicit CN parameter was specified,
2928 extracted from the CONNECT request. It is a misconfiguration
2929 to use setCommonName without an explicit parameter for
2930 intercepted or tproxied SSL connections.
2932 This clause only supports fast acl types.
2934 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2935 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2936 corresponding adaptation algorithm to generate the certificate and
2937 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2938 group (i.e., the first match wins within each algorithm group). If no
2939 acl(s) match, the default mimicking action takes place.
2941 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2942 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2943 CONNECT request that carries a domain name. In all other cases (CONNECT
2944 to an IP address or an intercepted SSL connection), Squid cannot detect
2945 the domain mismatch at certificate generation time when
2946 bump-server-first is used.
2949 NAME: sslpassword_program
2952 LOC: Config.Program.ssl_password
2955 Specify a program used for entering SSL key passphrases
2956 when using encrypted SSL certificate keys. If not specified
2957 keys must either be unencrypted, or Squid started with the -N
2958 option to allow it to query interactively for the passphrase.
2960 The key file name is given as argument to the program allowing
2961 selection of the right password if you have multiple encrypted
2966 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2967 -----------------------------------------------------------------------------
2970 NAME: sslcrtd_program
2973 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2974 LOC: Ssl::TheConfig.ssl_crtd
2976 Specify the location and options of the executable for ssl_crtd process.
2977 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2978 For more information use:
2979 @DEFAULT_SSL_CRTD@ -h
2982 NAME: sslcrtd_children
2983 TYPE: HelperChildConfig
2985 DEFAULT: 32 startup=5 idle=1
2986 LOC: Ssl::TheConfig.ssl_crtdChildren
2988 The maximum number of processes spawn to service ssl server.
2989 The maximum this may be safely set to is 32.
2991 The startup= and idle= options allow some measure of skew in your
2996 Sets the minimum number of processes to spawn when Squid
2997 starts or reconfigures. When set to zero the first request will
2998 cause spawning of the first child process to handle it.
3000 Starting too few children temporary slows Squid under load while it
3001 tries to spawn enough additional processes to cope with traffic.
3005 Sets a minimum of how many processes Squid is to try and keep available
3006 at all times. When traffic begins to rise above what the existing
3007 processes can handle this many more will be spawned up to the maximum
3008 configured. A minimum setting of 1 is required.
3012 Sets the maximum number of queued requests.
3013 If the queued requests exceed queue size for more than 3 minutes
3014 squid aborts its operation.
3015 The default value is set to 2*numberofchildren.
3017 You must have at least one ssl_crtd process.
3020 NAME: sslcrtvalidator_program
3024 LOC: Ssl::TheConfig.ssl_crt_validator
3026 Specify the location and options of the executable for ssl_crt_validator
3029 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
3032 ttl=n TTL in seconds for cached results. The default is 60 secs
3033 cache=n limit the result cache size. The default value is 2048
3036 NAME: sslcrtvalidator_children
3037 TYPE: HelperChildConfig
3039 DEFAULT: 32 startup=5 idle=1 concurrency=1
3040 LOC: Ssl::TheConfig.ssl_crt_validator_Children
3042 The maximum number of processes spawn to service SSL server.
3043 The maximum this may be safely set to is 32.
3045 The startup= and idle= options allow some measure of skew in your
3050 Sets the minimum number of processes to spawn when Squid
3051 starts or reconfigures. When set to zero the first request will
3052 cause spawning of the first child process to handle it.
3054 Starting too few children temporary slows Squid under load while it
3055 tries to spawn enough additional processes to cope with traffic.
3059 Sets a minimum of how many processes Squid is to try and keep available
3060 at all times. When traffic begins to rise above what the existing
3061 processes can handle this many more will be spawned up to the maximum
3062 configured. A minimum setting of 1 is required.
3066 The number of requests each certificate validator helper can handle in
3067 parallel. A value of 0 indicates the certficate validator does not
3068 support concurrency. Defaults to 1.
3070 When this directive is set to a value >= 1 then the protocol
3071 used to communicate with the helper is modified to include
3072 a request ID in front of the request/response. The request
3073 ID from the request must be echoed back with the response
3078 Sets the maximum number of queued requests.
3079 If the queued requests exceed queue size for more than 3 minutes
3080 squid aborts its operation.
3081 The default value is set to 2*numberofchildren.
3083 You must have at least one ssl_crt_validator process.
3087 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
3088 -----------------------------------------------------------------------------
3096 To specify other caches in a hierarchy, use the format:
3098 cache_peer hostname type http-port icp-port [options]
3103 # hostname type port port options
3104 # -------------------- -------- ----- ----- -----------
3105 cache_peer parent.foo.net parent 3128 3130 default
3106 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
3107 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
3108 cache_peer example.com parent 80 0 default
3109 cache_peer cdn.example.com sibling 3128 0
3111 type: either 'parent', 'sibling', or 'multicast'.
3113 proxy-port: The port number where the peer accept HTTP requests.
3114 For other Squid proxies this is usually 3128
3115 For web servers this is usually 80
3117 icp-port: Used for querying neighbor caches about objects.
3118 Set to 0 if the peer does not support ICP or HTCP.
3119 See ICP and HTCP options below for additional details.
3122 ==== ICP OPTIONS ====
3124 You MUST also set icp_port and icp_access explicitly when using these options.
3125 The defaults will prevent peer traffic using ICP.
3128 no-query Disable ICP queries to this neighbor.
3131 Indicates the named peer is a member of a multicast group.
3132 ICP queries will not be sent directly to the peer, but ICP
3133 replies will be accepted from it.
3135 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
3136 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
3139 To only send ICP queries to this neighbor infrequently.
3140 This is used to keep the neighbor round trip time updated
3141 and is usually used in conjunction with weighted-round-robin.
3144 ==== HTCP OPTIONS ====
3146 You MUST also set htcp_port and htcp_access explicitly when using these options.
3147 The defaults will prevent peer traffic using HTCP.
3150 htcp Send HTCP, instead of ICP, queries to the neighbor.
3151 You probably also want to set the "icp-port" to 4827
3152 instead of 3130. This directive accepts a comma separated
3153 list of options described below.
3155 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
3157 htcp=no-clr Send HTCP to the neighbor but without
3158 sending any CLR requests. This cannot be used with
3161 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
3162 This cannot be used with no-clr.
3165 Send HTCP to the neighbor including CLRs but only when
3166 they do not result from PURGE requests.
3169 Forward any HTCP CLR requests this proxy receives to the peer.
3172 ==== PEER SELECTION METHODS ====
3174 The default peer selection method is ICP, with the first responding peer
3175 being used as source. These options can be used for better load balancing.
3178 default This is a parent cache which can be used as a "last-resort"
3179 if a peer cannot be located by any of the peer-selection methods.
3180 If specified more than once, only the first is used.
3182 round-robin Load-Balance parents which should be used in a round-robin
3183 fashion in the absence of any ICP queries.
3184 weight=N can be used to add bias.
3186 weighted-round-robin
3187 Load-Balance parents which should be used in a round-robin
3188 fashion with the frequency of each parent being based on the
3189 round trip time. Closer parents are used more often.
3190 Usually used for background-ping parents.
3191 weight=N can be used to add bias.
3193 carp Load-Balance parents which should be used as a CARP array.
3194 The requests will be distributed among the parents based on the
3195 CARP load balancing hash function based on their weight.
3197 userhash Load-balance parents based on the client proxy_auth or ident username.
3199 sourcehash Load-balance parents based on the client source IP.
3202 To be used only for cache peers of type "multicast".
3203 ALL members of this multicast group have "sibling"
3204 relationship with it, not "parent". This is to a multicast
3205 group when the requested object would be fetched only from
3206 a "parent" cache, anyway. It's useful, e.g., when
3207 configuring a pool of redundant Squid proxies, being
3208 members of the same multicast group.
3211 ==== PEER SELECTION OPTIONS ====
3213 weight=N use to affect the selection of a peer during any weighted
3214 peer-selection mechanisms.
3215 The weight must be an integer; default is 1,
3216 larger weights are favored more.
3217 This option does not affect parent selection if a peering
3218 protocol is not in use.
3220 basetime=N Specify a base amount to be subtracted from round trip
3222 It is subtracted before division by weight in calculating
3223 which parent to fectch from. If the rtt is less than the
3224 base time the rtt is set to a minimal value.
3226 ttl=N Specify a TTL to use when sending multicast ICP queries
3228 Only useful when sending to a multicast group.
3229 Because we don't accept ICP replies from random
3230 hosts, you must configure other group members as
3231 peers with the 'multicast-responder' option.
3233 no-delay To prevent access to this neighbor from influencing the
3236 digest-url=URL Tell Squid to fetch the cache digest (if digests are
3237 enabled) for this host from the specified URL rather
3238 than the Squid default location.
3241 ==== CARP OPTIONS ====
3243 carp-key=key-specification
3244 use a different key than the full URL to hash against the peer.
3245 the key-specification is a comma-separated list of the keywords
3246 scheme, host, port, path, params
3247 Order is not important.
3249 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
3251 originserver Causes this parent to be contacted as an origin server.
3252 Meant to be used in accelerator setups when the peer
3256 Set the Host header of requests forwarded to this peer.
3257 Useful in accelerator setups where the server (peer)
3258 expects a certain domain name but clients may request
3259 others. ie example.com or www.example.com
3261 no-digest Disable request of cache digests.
3264 Disables requesting ICMP RTT database (NetDB).
3267 ==== AUTHENTICATION OPTIONS ====
3270 If this is a personal/workgroup proxy and your parent
3271 requires proxy authentication.
3273 Note: The string can include URL escapes (i.e. %20 for
3274 spaces). This also means % must be written as %%.
3277 Send login details received from client to this peer.
3278 Both Proxy- and WWW-Authorization headers are passed
3279 without alteration to the peer.
3280 Authentication is not required by Squid for this to work.
3282 Note: This will pass any form of authentication but
3283 only Basic auth will work through a proxy unless the
3284 connection-auth options are also used.
3286 login=PASS Send login details received from client to this peer.
3287 Authentication is not required by this option.
3289 If there are no client-provided authentication headers
3290 to pass on, but username and password are available
3291 from an external ACL user= and password= result tags
3292 they may be sent instead.
3294 Note: To combine this with proxy_auth both proxies must
3295 share the same user database as HTTP only allows for
3296 a single login (one for proxy, one for origin server).
3297 Also be warned this will expose your users proxy
3298 password to the peer. USE WITH CAUTION
3301 Send the username to the upstream cache, but with a
3302 fixed password. This is meant to be used when the peer
3303 is in another administrative domain, but it is still
3304 needed to identify each user.
3305 The star can optionally be followed by some extra
3306 information which is added to the username. This can
3307 be used to identify this proxy to the peer, similar to
3308 the login=username:password option above.
3311 If this is a personal/workgroup proxy and your parent
3312 requires a secure proxy authentication.
3313 The first principal from the default keytab or defined by
3314 the environment variable KRB5_KTNAME will be used.
3316 WARNING: The connection may transmit requests from multiple
3317 clients. Negotiate often assumes end-to-end authentication
3318 and a single-client. Which is not strictly true here.
3320 login=NEGOTIATE:principal_name
3321 If this is a personal/workgroup proxy and your parent
3322 requires a secure proxy authentication.
3323 The principal principal_name from the default keytab or
3324 defined by the environment variable KRB5_KTNAME will be
3327 WARNING: The connection may transmit requests from multiple
3328 clients. Negotiate often assumes end-to-end authentication
3329 and a single-client. Which is not strictly true here.
3331 connection-auth=on|off
3332 Tell Squid that this peer does or not support Microsoft
3333 connection oriented authentication, and any such
3334 challenges received from there should be ignored.
3335 Default is auto to automatically determine the status
3339 ==== SSL / HTTPS / TLS OPTIONS ====
3341 ssl Encrypt connections to this peer with SSL/TLS.
3343 sslcert=/path/to/ssl/certificate
3344 A client SSL certificate to use when connecting to
3347 sslkey=/path/to/ssl/key
3348 The private SSL key corresponding to sslcert above.
3349 If 'sslkey' is not specified 'sslcert' is assumed to
3350 reference a combined file containing both the
3351 certificate and the key.
3353 sslcipher=... The list of valid SSL ciphers to use when connecting
3357 The minimum TLS protocol version to permit. To control
3358 SSLv3 use the ssloptions= parameter.
3359 Supported Values: 1.0 (default), 1.1, 1.2
3361 ssloptions=... Specify various SSL implementation options:
3363 NO_SSLv3 Disallow the use of SSLv3
3365 NO_TLSv1 Disallow the use of TLSv1.0
3367 NO_TLSv1_1 Disallow the use of TLSv1.1
3369 NO_TLSv1_2 Disallow the use of TLSv1.2
3372 Always create a new key when using
3373 temporary/ephemeral DH key exchanges
3376 Disable use of RFC5077 session tickets.
3377 Some servers may have problems
3378 understanding the TLS extension due
3379 to ambiguous specification in RFC4507.
3381 ALL Enable various bug workarounds
3382 suggested as "harmless" by OpenSSL
3383 Be warned that this reduces SSL/TLS
3384 strength to some attacks.
3386 See the OpenSSL SSL_CTX_set_options documentation for a
3389 tls-cafile= PEM file containing CA certificates to use when verifying
3390 the peer certificate. May be repeated to load multiple files.
3392 sslcapath=... A directory containing additional CA certificates to
3393 use when verifying the peer certificate.
3394 Requires OpenSSL or LibreSSL.
3396 sslcrlfile=... A certificate revocation list file to use when
3397 verifying the peer certificate.
3399 sslflags=... Specify various flags modifying the SSL implementation:
3402 Accept certificates even if they fail to
3406 Don't verify the peer certificate
3407 matches the server name
3409 ssldomain= The peer name as advertised in it's certificate.
3410 Used for verifying the correctness of the received peer
3411 certificate. If not specified the peer hostname will be
3415 Enable the "Front-End-Https: On" header needed when
3416 using Squid as a SSL frontend in front of Microsoft OWA.
3417 See MS KB document Q307347 for details on this header.
3418 If set to auto the header will only be added if the
3419 request is forwarded as a https:// URL.
3422 Do not use the system default Trusted CA.
3424 ==== GENERAL OPTIONS ====
3427 A peer-specific connect timeout.
3428 Also see the peer_connect_timeout directive.
3430 connect-fail-limit=N
3431 How many times connecting to a peer must fail before
3432 it is marked as down. Standby connection failures
3433 count towards this limit. Default is 10.
3435 allow-miss Disable Squid's use of only-if-cached when forwarding
3436 requests to siblings. This is primarily useful when
3437 icp_hit_stale is used by the sibling. To extensive use
3438 of this option may result in forwarding loops, and you
3439 should avoid having two-way peerings with this option.
3440 For example to deny peer usage on requests from peer
3441 by denying cache_peer_access if the source is a peer.
3443 max-conn=N Limit the number of concurrent connections the Squid
3444 may open to this peer, including already opened idle
3445 and standby connections. There is no peer-specific
3446 connection limit by default.
3448 A peer exceeding the limit is not used for new
3449 requests unless a standby connection is available.
3451 max-conn currently works poorly with idle persistent
3452 connections: When a peer reaches its max-conn limit,
3453 and there are idle persistent connections to the peer,
3454 the peer may not be selected because the limiting code
3455 does not know whether Squid can reuse those idle
3458 standby=N Maintain a pool of N "hot standby" connections to an
3459 UP peer, available for requests when no idle
3460 persistent connection is available (or safe) to use.
3461 By default and with zero N, no such pool is maintained.
3462 N must not exceed the max-conn limit (if any).
3464 At start or after reconfiguration, Squid opens new TCP
3465 standby connections until there are N connections
3466 available and then replenishes the standby pool as
3467 opened connections are used up for requests. A used
3468 connection never goes back to the standby pool, but
3469 may go to the regular idle persistent connection pool
3470 shared by all peers and origin servers.
3472 Squid never opens multiple new standby connections
3473 concurrently. This one-at-a-time approach minimizes
3474 flooding-like effect on peers. Furthermore, just a few
3475 standby connections should be sufficient in most cases
3476 to supply most new requests with a ready-to-use
3479 Standby connections obey server_idle_pconn_timeout.
3480 For the feature to work as intended, the peer must be
3481 configured to accept and keep them open longer than
3482 the idle timeout at the connecting Squid, to minimize
3483 race conditions typical to idle used persistent
3484 connections. Default request_timeout and
3485 server_idle_pconn_timeout values ensure such a
3488 name=xxx Unique name for the peer.
3489 Required if you have multiple peers on the same host
3490 but different ports.
3491 This name can be used in cache_peer_access and similar
3492 directives to dentify the peer.
3493 Can be used by outgoing access controls through the
3496 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3497 requests to this peer. Use normal address selection instead.
3498 This overrides the spoof_client_ip ACL.
3500 proxy-only objects fetched from the peer will not be stored locally.
3504 NAME: cache_peer_access
3509 Use to limit the requests for which a neighbor proxy will be
3510 queried. Peers with no restrictions are queried for all requests.
3513 cache_peer_access cache-host allow|deny [!]aclname ...
3515 The syntax is identical to 'http_access' and the other lists of
3516 ACL elements. See the comments for 'http_access', or the
3517 Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
3520 NAME: neighbor_type_domain
3521 TYPE: hostdomaintype
3523 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3526 Modify the cache_peer neighbor type when passing requests
3527 about specific domains to the peer.
3530 neighbor_type_domain neighbor parent|sibling domain domain ...
3533 cache_peer foo.example.com parent 3128 3130
3534 neighbor_type_domain foo.example.com sibling .au .de
3536 The above configuration treats all requests to foo.example.com as a
3537 parent proxy unless the request is for a .au or .de ccTLD domain name.
3540 NAME: dead_peer_timeout
3544 LOC: Config.Timeout.deadPeer
3546 This controls how long Squid waits to declare a peer cache
3547 as "dead." If there are no ICP replies received in this
3548 amount of time, Squid will declare the peer dead and not
3549 expect to receive any further ICP replies. However, it
3550 continues to send ICP queries, and will mark the peer as
3551 alive upon receipt of the first subsequent ICP reply.
3553 This timeout also affects when Squid expects to receive ICP
3554 replies from peers. If more than 'dead_peer' seconds have
3555 passed since the last ICP reply was received, Squid will not
3556 expect to receive an ICP reply on the next query. Thus, if
3557 your time between requests is greater than this timeout, you
3558 will see a lot of requests sent DIRECT to origin servers
3559 instead of to your parents.
3562 NAME: forward_max_tries
3565 LOC: Config.forward_max_tries
3567 Controls how many different forward paths Squid will try
3568 before giving up. See also forward_timeout.
3570 NOTE: connect_retries (default: none) can make each of these
3571 possible forwarding paths be tried multiple times.
3575 MEMORY CACHE OPTIONS
3576 -----------------------------------------------------------------------------
3583 LOC: Config.memMaxSize
3585 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3586 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3587 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3588 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3590 'cache_mem' specifies the ideal amount of memory to be used
3592 * In-Transit objects
3594 * Negative-Cached objects
3596 Data for these objects are stored in 4 KB blocks. This
3597 parameter specifies the ideal upper limit on the total size of
3598 4 KB blocks allocated. In-Transit objects take the highest
3601 In-transit objects have priority over the others. When
3602 additional space is needed for incoming data, negative-cached
3603 and hot objects will be released. In other words, the
3604 negative-cached and hot objects will fill up any unused space
3605 not needed for in-transit objects.
3607 If circumstances require, this limit will be exceeded.
3608 Specifically, if your incoming request rate requires more than
3609 'cache_mem' of memory to hold in-transit objects, Squid will
3610 exceed this limit to satisfy the new requests. When the load
3611 decreases, blocks will be freed until the high-water mark is
3612 reached. Thereafter, blocks will be used to store hot
3615 If shared memory caching is enabled, Squid does not use the shared
3616 cache space for in-transit objects, but they still consume as much
3617 local memory as they need. For more details about the shared memory
3618 cache, see memory_cache_shared.
3621 NAME: maximum_object_size_in_memory
3625 LOC: Config.Store.maxInMemObjSize
3627 Objects greater than this size will not be attempted to kept in
3628 the memory cache. This should be set high enough to keep objects
3629 accessed frequently in memory to improve performance whilst low
3630 enough to keep larger objects from hoarding cache_mem.
3633 NAME: memory_cache_shared
3636 LOC: Config.memShared
3638 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3640 Controls whether the memory cache is shared among SMP workers.
3642 The shared memory cache is meant to occupy cache_mem bytes and replace
3643 the non-shared memory cache, although some entities may still be
3644 cached locally by workers for now (e.g., internal and in-transit
3645 objects may be served from a local memory cache even if shared memory
3646 caching is enabled).
3648 By default, the memory cache is shared if and only if all of the
3649 following conditions are satisfied: Squid runs in SMP mode with
3650 multiple workers, cache_mem is positive, and Squid environment
3651 supports required IPC primitives (e.g., POSIX shared memory segments
3652 and GCC-style atomic operations).
3654 To avoid blocking locks, shared memory uses opportunistic algorithms
3655 that do not guarantee that every cachable entity that could have been
3656 shared among SMP workers will actually be shared.
3658 Currently, entities exceeding 32KB in size cannot be shared.
3661 NAME: memory_cache_mode
3665 DEFAULT_DOC: Keep the most recently fetched objects in memory
3667 Controls which objects to keep in the memory cache (cache_mem)
3669 always Keep most recently fetched objects in memory (default)
3671 disk Only disk cache hits are kept in memory, which means
3672 an object must first be cached on disk and then hit
3673 a second time before cached in memory.
3675 network Only objects fetched from network is kept in memory
3678 NAME: memory_replacement_policy
3680 LOC: Config.memPolicy
3683 The memory replacement policy parameter determines which
3684 objects are purged from memory when memory space is needed.
3686 See cache_replacement_policy for details on algorithms.
3691 -----------------------------------------------------------------------------
3694 NAME: cache_replacement_policy
3696 LOC: Config.replPolicy
3699 The cache replacement policy parameter determines which
3700 objects are evicted (replaced) when disk space is needed.
3702 lru : Squid's original list based LRU policy
3703 heap GDSF : Greedy-Dual Size Frequency
3704 heap LFUDA: Least Frequently Used with Dynamic Aging
3705 heap LRU : LRU policy implemented using a heap
3707 Applies to any cache_dir lines listed below this directive.
3709 The LRU policies keeps recently referenced objects.
3711 The heap GDSF policy optimizes object hit rate by keeping smaller
3712 popular objects in cache so it has a better chance of getting a
3713 hit. It achieves a lower byte hit rate than LFUDA though since
3714 it evicts larger (possibly popular) objects.
3716 The heap LFUDA policy keeps popular objects in cache regardless of
3717 their size and thus optimizes byte hit rate at the expense of
3718 hit rate since one large, popular object will prevent many
3719 smaller, slightly less popular objects from being cached.
3721 Both policies utilize a dynamic aging mechanism that prevents
3722 cache pollution that can otherwise occur with frequency-based
3723 replacement policies.
3725 NOTE: if using the LFUDA replacement policy you should increase
3726 the value of maximum_object_size above its default of 4 MB to
3727 to maximize the potential byte hit rate improvement of LFUDA.
3729 For more information about the GDSF and LFUDA cache replacement
3730 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3731 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3734 NAME: minimum_object_size
3738 DEFAULT_DOC: no limit
3739 LOC: Config.Store.minObjectSize
3741 Objects smaller than this size will NOT be saved on disk. The
3742 value is specified in bytes, and the default is 0 KB, which
3743 means all responses can be stored.
3746 NAME: maximum_object_size
3750 LOC: Config.Store.maxObjectSize
3752 Set the default value for max-size parameter on any cache_dir.
3753 The value is specified in bytes, and the default is 4 MB.
3755 If you wish to get a high BYTES hit ratio, you should probably
3756 increase this (one 32 MB object hit counts for 3200 10KB
3759 If you wish to increase hit ratio more than you want to
3760 save bandwidth you should leave this low.
3762 NOTE: if using the LFUDA replacement policy you should increase
3763 this value to maximize the byte hit rate improvement of LFUDA!
3764 See cache_replacement_policy for a discussion of this policy.
3770 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3771 LOC: Config.cacheSwap
3774 cache_dir Type Directory-Name Fs-specific-data [options]
3776 You can specify multiple cache_dir lines to spread the
3777 cache among different disk partitions.
3779 Type specifies the kind of storage system to use. Only "ufs"
3780 is built by default. To enable any of the other storage systems
3781 see the --enable-storeio configure option.
3783 'Directory' is a top-level directory where cache swap
3784 files will be stored. If you want to use an entire disk
3785 for caching, this can be the mount-point directory.
3786 The directory must exist and be writable by the Squid
3787 process. Squid will NOT create this directory for you.
3789 In SMP configurations, cache_dir must not precede the workers option
3790 and should use configuration macros or conditionals to give each
3791 worker interested in disk caching a dedicated cache directory.
3794 ==== The ufs store type ====
3796 "ufs" is the old well-known Squid storage format that has always
3800 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3802 'Mbytes' is the amount of disk space (MB) to use under this
3803 directory. The default is 100 MB. Change this to suit your
3804 configuration. Do NOT put the size of your disk drive here.
3805 Instead, if you want Squid to use the entire disk drive,
3806 subtract 20% and use that value.
3808 'L1' is the number of first-level subdirectories which
3809 will be created under the 'Directory'. The default is 16.
3811 'L2' is the number of second-level subdirectories which
3812 will be created under each first-level directory. The default
3816 ==== The aufs store type ====
3818 "aufs" uses the same storage format as "ufs", utilizing
3819 POSIX-threads to avoid blocking the main Squid process on
3820 disk-I/O. This was formerly known in Squid as async-io.
3823 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3825 see argument descriptions under ufs above
3828 ==== The diskd store type ====
3830 "diskd" uses the same storage format as "ufs", utilizing a
3831 separate process to avoid blocking the main Squid process on
3835 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3837 see argument descriptions under ufs above
3839 Q1 specifies the number of unacknowledged I/O requests when Squid
3840 stops opening new files. If this many messages are in the queues,
3841 Squid won't open new files. Default is 64
3843 Q2 specifies the number of unacknowledged messages when Squid
3844 starts blocking. If this many messages are in the queues,
3845 Squid blocks until it receives some replies. Default is 72
3847 When Q1 < Q2 (the default), the cache directory is optimized
3848 for lower response time at the expense of a decrease in hit
3849 ratio. If Q1 > Q2, the cache directory is optimized for
3850 higher hit ratio at the expense of an increase in response
3854 ==== The rock store type ====
3857 cache_dir rock Directory-Name Mbytes [options]
3859 The Rock Store type is a database-style storage. All cached
3860 entries are stored in a "database" file, using fixed-size slots.
3861 A single entry occupies one or more slots.
3863 If possible, Squid using Rock Store creates a dedicated kid
3864 process called "disker" to avoid blocking Squid worker(s) on disk
3865 I/O. One disker kid is created for each rock cache_dir. Diskers
3866 are created only when Squid, running in daemon mode, has support
3867 for the IpcIo disk I/O module.
3869 swap-timeout=msec: Squid will not start writing a miss to or
3870 reading a hit from disk if it estimates that the swap operation
3871 will take more than the specified number of milliseconds. By
3872 default and when set to zero, disables the disk I/O time limit
3873 enforcement. Ignored when using blocking I/O module because
3874 blocking synchronous I/O does not allow Squid to estimate the
3875 expected swap wait time.
3877 max-swap-rate=swaps/sec: Artificially limits disk access using
3878 the specified I/O rate limit. Swap out requests that
3879 would cause the average I/O rate to exceed the limit are
3880 delayed. Individual swap in requests (i.e., hits or reads) are
3881 not delayed, but they do contribute to measured swap rate and
3882 since they are placed in the same FIFO queue as swap out
3883 requests, they may wait longer if max-swap-rate is smaller.
3884 This is necessary on file systems that buffer "too
3885 many" writes and then start blocking Squid and other processes
3886 while committing those writes to disk. Usually used together
3887 with swap-timeout to avoid excessive delays and queue overflows
3888 when disk demand exceeds available disk "bandwidth". By default
3889 and when set to zero, disables the disk I/O rate limit
3890 enforcement. Currently supported by IpcIo module only.
3892 slot-size=bytes: The size of a database "record" used for
3893 storing cached responses. A cached response occupies at least
3894 one slot and all database I/O is done using individual slots so
3895 increasing this parameter leads to more disk space waste while
3896 decreasing it leads to more disk I/O overheads. Should be a
3897 multiple of your operating system I/O page size. Defaults to
3898 16KBytes. A housekeeping header is stored with each slot and
3899 smaller slot-sizes will be rejected. The header is smaller than
3903 ==== COMMON OPTIONS ====
3905 no-store no new objects should be stored to this cache_dir.
3907 min-size=n the minimum object size in bytes this cache_dir
3908 will accept. It's used to restrict a cache_dir
3909 to only store large objects (e.g. AUFS) while
3910 other stores are optimized for smaller objects
3914 max-size=n the maximum object size in bytes this cache_dir
3916 The value in maximum_object_size directive sets
3917 the default unless more specific details are
3918 available (ie a small store capacity).
3920 Note: To make optimal use of the max-size limits you should order
3921 the cache_dir lines with the smallest max-size value first.
3925 # Uncomment and adjust the following to add a disk cache directory.
3926 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3930 NAME: store_dir_select_algorithm
3932 LOC: Config.store_dir_select_algorithm
3935 How Squid selects which cache_dir to use when the response
3936 object will fit into more than one.
3938 Regardless of which algorithm is used the cache_dir min-size
3939 and max-size parameters are obeyed. As such they can affect
3940 the selection algorithm by limiting the set of considered
3947 This algorithm is suited to caches with similar cache_dir
3948 sizes and disk speeds.
3950 The disk with the least I/O pending is selected.
3951 When there are multiple disks with the same I/O load ranking
3952 the cache_dir with most available capacity is selected.
3954 When a mix of cache_dir sizes are configured the faster disks
3955 have a naturally lower I/O loading and larger disks have more
3956 capacity. So space used to store objects and data throughput
3957 may be very unbalanced towards larger disks.
3962 This algorithm is suited to caches with unequal cache_dir
3965 Each cache_dir is selected in a rotation. The next suitable
3968 Available cache_dir capacity is only considered in relation
3969 to whether the object will fit and meets the min-size and
3970 max-size parameters.
3972 Disk I/O loading is only considered to prevent overload on slow
3973 disks. This algorithm does not spread objects by size, so any
3974 I/O loading per-disk may appear very unbalanced and volatile.
3976 If several cache_dirs use similar min-size, max-size, or other
3977 limits to to reject certain responses, then do not group such
3978 cache_dir lines together, to avoid round-robin selection bias
3979 towards the first cache_dir after the group. Instead, interleave
3980 cache_dir lines from different groups. For example:
3982 store_dir_select_algorithm round-robin
3983 cache_dir rock /hdd1 ... min-size=100000
3984 cache_dir rock /ssd1 ... max-size=99999
3985 cache_dir rock /hdd2 ... min-size=100000
3986 cache_dir rock /ssd2 ... max-size=99999
3987 cache_dir rock /hdd3 ... min-size=100000
3988 cache_dir rock /ssd3 ... max-size=99999
3991 NAME: max_open_disk_fds
3993 LOC: Config.max_open_disk_fds
3995 DEFAULT_DOC: no limit
3997 To avoid having disk as the I/O bottleneck Squid can optionally
3998 bypass the on-disk cache if more than this amount of disk file
3999 descriptors are open.
4001 A value of 0 indicates no limit.
4004 NAME: cache_swap_low
4005 COMMENT: (percent, 0-100)
4008 LOC: Config.Swap.lowWaterMark
4010 The low-water mark for AUFS/UFS/diskd cache object eviction by
4011 the cache_replacement_policy algorithm.
4013 Removal begins when the swap (disk) usage of a cache_dir is
4014 above this low-water mark and attempts to maintain utilization
4015 near the low-water mark.
4017 As swap utilization increases towards the high-water mark set
4018 by cache_swap_high object eviction becomes more agressive.
4020 The value difference in percentages between low- and high-water
4021 marks represent an eviction rate of 300 objects per second and
4022 the rate continues to scale in agressiveness by multiples of
4023 this above the high-water mark.
4025 Defaults are 90% and 95%. If you have a large cache, 5% could be
4026 hundreds of MB. If this is the case you may wish to set these
4027 numbers closer together.
4029 See also cache_swap_high and cache_replacement_policy
4032 NAME: cache_swap_high
4033 COMMENT: (percent, 0-100)
4036 LOC: Config.Swap.highWaterMark
4038 The high-water mark for AUFS/UFS/diskd cache object eviction by
4039 the cache_replacement_policy algorithm.
4041 Removal begins when the swap (disk) usage of a cache_dir is
4042 above the low-water mark set by cache_swap_low and attempts to
4043 maintain utilization near the low-water mark.
4045 As swap utilization increases towards this high-water mark object
4046 eviction becomes more agressive.
4048 The value difference in percentages between low- and high-water
4049 marks represent an eviction rate of 300 objects per second and
4050 the rate continues to scale in agressiveness by multiples of
4051 this above the high-water mark.
4053 Defaults are 90% and 95%. If you have a large cache, 5% could be
4054 hundreds of MB. If this is the case you may wish to set these
4055 numbers closer together.
4057 See also cache_swap_low and cache_replacement_policy
4062 -----------------------------------------------------------------------------
4069 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
4073 logformat <name> <format specification>
4075 Defines an access log format.
4077 The <format specification> is a string with embedded % format codes
4079 % format codes all follow the same basic structure where all but
4080 the formatcode is optional. Output strings are automatically escaped
4081 as required according to their context and the output format
4082 modifiers are usually not needed, but can be specified if an explicit
4083 output format is desired.
4085 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
4087 " output in quoted string format
4088 [ output in squid text log format as used by log_mime_hdrs
4089 # output in URL quoted format
4094 width minimum and/or maximum field width:
4095 [width_min][.width_max]
4096 When minimum starts with 0, the field is zero-padded.
4097 String values exceeding maximum width are truncated.
4099 {arg} argument such as header name etc
4103 % a literal % character
4104 sn Unique sequence number per log line entry
4105 err_code The ID of an error response served by Squid or
4106 a similar internal error identifier.
4107 err_detail Additional err_code-dependent error information.
4108 note The annotation specified by the argument. Also
4109 logs the adaptation meta headers set by the
4110 adaptation_meta configuration parameter.
4111 If no argument given all annotations logged.
4112 The argument may include a separator to use with
4115 By default, multiple note values are separated with ","
4116 and multiple notes are separated with "\r\n".
4117 When logging named notes with %{name}note, the
4118 explicitly configured separator is used between note
4119 values. When logging all notes with %note, the
4120 explicitly configured separator is used between
4121 individual notes. There is currently no way to
4122 specify both value and notes separators when logging
4123 all notes with %note.
4125 Connection related format codes:
4127 >a Client source IP address
4129 >p Client source port
4130 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
4131 >la Local IP address the client connected to
4132 >lp Local port number the client connected to
4133 >qos Client connection TOS/DSCP value set by Squid
4134 >nfmark Client connection netfilter mark set by Squid
4136 la Local listening IP address the client connection was connected to.
4137 lp Local listening port number the client connection was connected to.
4139 <a Server IP address of the last server or peer connection
4140 <A Server FQDN or peer name
4141 <p Server port number of the last server or peer connection
4142 <la Local IP address of the last server or peer connection
4143 <lp Local port number of the last server or peer connection
4144 <qos Server connection TOS/DSCP value set by Squid
4145 <nfmark Server connection netfilter mark set by Squid
4147 Time related format codes:
4149 ts Seconds since epoch
4150 tu subsecond time (milliseconds)
4151 tl Local time. Optional strftime format argument
4152 default %d/%b/%Y:%H:%M:%S %z
4153 tg GMT time. Optional strftime format argument
4154 default %d/%b/%Y:%H:%M:%S %z
4155 tr Response time (milliseconds)
4156 dt Total time spent making DNS lookups (milliseconds)
4157 tS Approximate master transaction start time in
4158 <full seconds since epoch>.<fractional seconds> format.
4159 Currently, Squid considers the master transaction
4160 started when a complete HTTP request header initiating
4161 the transaction is received from the client. This is
4162 the same value that Squid uses to calculate transaction
4163 response time when logging %tr to access.log. Currently,
4164 Squid uses millisecond resolution for %tS values,
4165 similar to the default access.log "current time" field
4168 Access Control related format codes:
4170 et Tag returned by external acl
4171 ea Log string returned by external acl
4172 un User name (any available)
4173 ul User name from authentication
4174 ue User name from external acl helper
4175 ui User name from ident
4176 un A user name. Expands to the first available name
4177 from the following list of information sources:
4178 - authenticated user name, like %ul
4179 - user name supplied by an external ACL, like %ue
4180 - SSL client name, like %us
4181 - ident user name, like %ui
4182 credentials Client credentials. The exact meaning depends on
4183 the authentication scheme: For Basic authentication,
4184 it is the password; for Digest, the realm sent by the
4185 client; for NTLM and Negotiate, the client challenge
4186 or client credentials prefixed with "YR " or "KK ".
4188 HTTP related format codes:
4192 [http::]rm Request method (GET/POST etc)
4193 [http::]>rm Request method from client
4194 [http::]<rm Request method sent to server or peer
4195 [http::]ru Request URL from client (historic, filtered for logging)
4196 [http::]>ru Request URL from client
4197 [http::]<ru Request URL sent to server or peer
4198 [http::]>rs Request URL scheme from client
4199 [http::]<rs Request URL scheme sent to server or peer
4200 [http::]>rd Request URL domain from client
4201 [http::]<rd Request URL domain sent to server or peer
4202 [http::]>rP Request URL port from client
4203 [http::]<rP Request URL port sent to server or peer
4204 [http::]rp Request URL path excluding hostname
4205 [http::]>rp Request URL path excluding hostname from client
4206 [http::]<rp Request URL path excluding hostname sent to server or peer
4207 [http::]rv Request protocol version
4208 [http::]>rv Request protocol version from client
4209 [http::]<rv Request protocol version sent to server or peer
4211 [http::]>h Original received request header.
4212 Usually differs from the request header sent by
4213 Squid, although most fields are often preserved.
4214 Accepts optional header field name/value filter
4215 argument using name[:[separator]element] format.
4216 [http::]>ha Received request header after adaptation and
4217 redirection (pre-cache REQMOD vectoring point).
4218 Usually differs from the request header sent by
4219 Squid, although most fields are often preserved.
4220 Optional header name argument as for >h
4224 [http::]<Hs HTTP status code received from the next hop
4225 [http::]>Hs HTTP status code sent to the client
4227 [http::]<h Reply header. Optional header name argument
4230 [http::]mt MIME content type
4235 [http::]st Total size of request + reply traffic with client
4236 [http::]>st Total size of request received from client.
4237 Excluding chunked encoding bytes.
4238 [http::]<st Total size of reply sent to client (after adaptation)
4240 [http::]>sh Size of request headers received from client
4241 [http::]<sh Size of reply headers sent to client (after adaptation)
4243 [http::]<sH Reply high offset sent
4244 [http::]<sS Upstream object size
4246 [http::]<bs Number of HTTP-equivalent message body bytes
4247 received from the next hop, excluding chunked
4248 transfer encoding and control messages.
4249 Generated FTP/Gopher listings are treated as
4254 [http::]<pt Peer response time in milliseconds. The timer starts
4255 when the last request byte is sent to the next hop
4256 and stops when the last response byte is received.
4257 [http::]<tt Total time in milliseconds. The timer
4258 starts with the first connect request (or write I/O)
4259 sent to the first selected peer. The timer stops
4260 with the last I/O with the last peer.
4262 Squid handling related format codes:
4264 Ss Squid request status (TCP_MISS etc)
4265 Sh Squid hierarchy status (DEFAULT_PARENT etc)
4267 SSL-related format codes:
4269 ssl::bump_mode SslBump decision for the transaction:
4271 For CONNECT requests that initiated bumping of
4272 a connection and for any request received on
4273 an already bumped connection, Squid logs the
4274 corresponding SslBump mode ("server-first" or
4275 "client-first"). See the ssl_bump option for
4276 more information about these modes.
4278 A "none" token is logged for requests that
4279 triggered "ssl_bump" ACL evaluation matching
4280 either a "none" rule or no rules at all.
4282 In all other cases, a single dash ("-") is
4285 ssl::>sni SSL client SNI sent to Squid. Available only
4286 after the peek, stare, or splice SSL bumping
4290 The Subject field of the received client
4291 SSL certificate or a dash ('-') if Squid has
4292 received an invalid/malformed certificate or
4293 no certificate at all. Consider encoding the
4294 logged value because Subject often has spaces.
4297 The Issuer field of the received client
4298 SSL certificate or a dash ('-') if Squid has
4299 received an invalid/malformed certificate or
4300 no certificate at all. Consider encoding the
4301 logged value because Issuer often has spaces.
4304 The list of certificate validation errors
4305 detected by Squid (including OpenSSL and
4306 certificate validation helper components). The
4307 errors are listed in the discovery order. By
4308 default, the error codes are separated by ':'.
4309 Accepts an optional separator argument.
4311 If ICAP is enabled, the following code becomes available (as
4312 well as ICAP log codes documented with the icap_log option):
4314 icap::tt Total ICAP processing time for the HTTP
4315 transaction. The timer ticks when ICAP
4316 ACLs are checked and when ICAP
4317 transaction is in progress.
4319 If adaptation is enabled the following codes become available:
4321 adapt::<last_h The header of the last ICAP response or
4322 meta-information from the last eCAP
4323 transaction related to the HTTP transaction.
4324 Like <h, accepts an optional header name
4327 adapt::sum_trs Summed adaptation transaction response
4328 times recorded as a comma-separated list in
4329 the order of transaction start time. Each time
4330 value is recorded as an integer number,
4331 representing response time of one or more
4332 adaptation (ICAP or eCAP) transaction in
4333 milliseconds. When a failed transaction is
4334 being retried or repeated, its time is not
4335 logged individually but added to the
4336 replacement (next) transaction. See also:
4339 adapt::all_trs All adaptation transaction response times.
4340 Same as adaptation_strs but response times of
4341 individual transactions are never added
4342 together. Instead, all transaction response
4343 times are recorded individually.
4345 You can prefix adapt::*_trs format codes with adaptation
4346 service name in curly braces to record response time(s) specific
4347 to that service. For example: %{my_service}adapt::sum_trs
4349 The default formats available (which do not need re-defining) are:
4351 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
4352 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
4353 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
4354 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
4355 logformat useragent %>a [%tl] "%{User-Agent}>h"
4357 NOTE: When the log_mime_hdrs directive is set to ON.
4358 The squid, common and combined formats have a safely encoded copy
4359 of the mime headers appended to each line within a pair of brackets.
4361 NOTE: The common and combined formats are not quite true to the Apache definition.
4362 The logs from Squid contain an extra status and hierarchy code appended.
4366 NAME: access_log cache_access_log
4368 LOC: Config.Log.accesslogs
4369 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
4371 Configures whether and how Squid logs HTTP and ICP transactions.
4372 If access logging is enabled, a single line is logged for every
4373 matching HTTP or ICP request. The recommended directive formats are:
4375 access_log <module>:<place> [option ...] [acl acl ...]
4376 access_log none [acl acl ...]
4378 The following directive format is accepted but may be deprecated:
4379 access_log <module>:<place> [<logformat name> [acl acl ...]]
4381 In most cases, the first ACL name must not contain the '=' character
4382 and should not be equal to an existing logformat name. You can always
4383 start with an 'all' ACL to work around those restrictions.
4385 Will log to the specified module:place using the specified format (which
4386 must be defined in a logformat directive) those entries which match
4387 ALL the acl's specified (which must be defined in acl clauses).
4388 If no acl is specified, all requests will be logged to this destination.
4390 ===== Available options for the recommended directive format =====
4392 logformat=name Names log line format (either built-in or
4393 defined by a logformat directive). Defaults
4396 buffer-size=64KB Defines approximate buffering limit for log
4397 records (see buffered_logs). Squid should not
4398 keep more than the specified size and, hence,
4399 should flush records before the buffer becomes
4400 full to avoid overflows under normal
4401 conditions (the exact flushing algorithm is
4402 module-dependent though). The on-error option
4403 controls overflow handling.
4405 on-error=die|drop Defines action on unrecoverable errors. The
4406 'drop' action ignores (i.e., does not log)
4407 affected log records. The default 'die' action
4408 kills the affected worker. The drop action
4409 support has not been tested for modules other
4412 rotate=N Specifies the number of log file rotations to
4413 make when you run 'squid -k rotate'. The default
4414 is to obey the logfile_rotate directive. Setting
4415 rotate=0 will disable the file name rotation,
4416 but the log files are still closed and re-opened.
4417 This will enable you to rename the logfiles
4418 yourself just before sending the rotate signal.
4419 Only supported by the stdio module.
4421 ===== Modules Currently available =====
4423 none Do not log any requests matching these ACL.
4424 Do not specify Place or logformat name.
4426 stdio Write each log line to disk immediately at the completion of
4428 Place: the filename and path to be written.
4430 daemon Very similar to stdio. But instead of writing to disk the log
4431 line is passed to a daemon helper for asychronous handling instead.
4432 Place: varies depending on the daemon.
4434 log_file_daemon Place: the file name and path to be written.
4436 syslog To log each request via syslog facility.
4437 Place: The syslog facility and priority level for these entries.
4438 Place Format: facility.priority
4440 where facility could be any of:
4441 authpriv, daemon, local0 ... local7 or user.
4443 And priority could be any of:
4444 err, warning, notice, info, debug.
4446 udp To send each log line as text data to a UDP receiver.
4447 Place: The destination host name or IP and port.
4448 Place Format: //host:port
4450 tcp To send each log line as text data to a TCP receiver.
4451 Lines may be accumulated before sending (see buffered_logs).
4452 Place: The destination host name or IP and port.
4453 Place Format: //host:port
4456 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4462 LOC: Config.Log.icaplogs
4465 ICAP log files record ICAP transaction summaries, one line per
4468 The icap_log option format is:
4469 icap_log <filepath> [<logformat name> [acl acl ...]]
4470 icap_log none [acl acl ...]]
4472 Please see access_log option documentation for details. The two
4473 kinds of logs share the overall configuration approach and many
4476 ICAP processing of a single HTTP message or transaction may
4477 require multiple ICAP transactions. In such cases, multiple
4478 ICAP transaction log lines will correspond to a single access
4481 ICAP log uses logformat codes that make sense for an ICAP
4482 transaction. Header-related codes are applied to the HTTP header
4483 embedded in an ICAP server response, with the following caveats:
4484 For REQMOD, there is no HTTP response header unless the ICAP
4485 server performed request satisfaction. For RESPMOD, the HTTP
4486 request header is the header sent to the ICAP server. For
4487 OPTIONS, there are no HTTP headers.
4489 The following format codes are also available for ICAP logs:
4491 icap::<A ICAP server IP address. Similar to <A.
4493 icap::<service_name ICAP service name from the icap_service
4494 option in Squid configuration file.
4496 icap::ru ICAP Request-URI. Similar to ru.
4498 icap::rm ICAP request method (REQMOD, RESPMOD, or
4499 OPTIONS). Similar to existing rm.
4501 icap::>st Bytes sent to the ICAP server (TCP payload
4502 only; i.e., what Squid writes to the socket).
4504 icap::<st Bytes received from the ICAP server (TCP
4505 payload only; i.e., what Squid reads from
4508 icap::<bs Number of message body bytes received from the
4509 ICAP server. ICAP message body, if any, usually
4510 includes encapsulated HTTP message headers and
4511 possibly encapsulated HTTP message body. The
4512 HTTP body part is dechunked before its size is
4515 icap::tr Transaction response time (in
4516 milliseconds). The timer starts when
4517 the ICAP transaction is created and
4518 stops when the transaction is completed.
4521 icap::tio Transaction I/O time (in milliseconds). The
4522 timer starts when the first ICAP request
4523 byte is scheduled for sending. The timers
4524 stops when the last byte of the ICAP response
4527 icap::to Transaction outcome: ICAP_ERR* for all
4528 transaction errors, ICAP_OPT for OPTION
4529 transactions, ICAP_ECHO for 204
4530 responses, ICAP_MOD for message
4531 modification, and ICAP_SAT for request
4532 satisfaction. Similar to Ss.
4534 icap::Hs ICAP response status code. Similar to Hs.
4536 icap::>h ICAP request header(s). Similar to >h.
4538 icap::<h ICAP response header(s). Similar to <h.
4540 The default ICAP log format, which can be used without an explicit
4541 definition, is called icap_squid:
4543 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
4545 See also: logformat, log_icap, and %adapt::<last_h
4548 NAME: logfile_daemon
4550 DEFAULT: @DEFAULT_LOGFILED@
4551 LOC: Log::TheConfig.logfile_daemon
4553 Specify the path to the logfile-writing daemon. This daemon is
4554 used to write the access and store logs, if configured.
4556 Squid sends a number of commands to the log daemon:
4557 L<data>\n - logfile data
4562 r<n>\n - set rotate count to <n>
4563 b<n>\n - 1 = buffer output, 0 = don't buffer output
4565 No responses is expected.
4568 NAME: stats_collection
4570 LOC: Config.accessList.stats_collection
4572 DEFAULT_DOC: Allow logging for all transactions.
4573 COMMENT: allow|deny acl acl...
4575 This options allows you to control which requests gets accounted
4576 in performance counters.
4578 This clause only supports fast acl types.
4579 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4582 NAME: cache_store_log
4585 LOC: Config.Log.store
4587 Logs the activities of the storage manager. Shows which
4588 objects are ejected from the cache, and which objects are
4589 saved and for how long.
4590 There are not really utilities to analyze this data, so you can safely
4591 disable it (the default).
4593 Store log uses modular logging outputs. See access_log for the list
4594 of modules supported.
4597 cache_store_log stdio:@DEFAULT_STORE_LOG@
4598 cache_store_log daemon:@DEFAULT_STORE_LOG@
4601 NAME: cache_swap_state cache_swap_log
4603 LOC: Config.Log.swap
4605 DEFAULT_DOC: Store the journal inside its cache_dir
4607 Location for the cache "swap.state" file. This index file holds
4608 the metadata of objects saved on disk. It is used to rebuild
4609 the cache during startup. Normally this file resides in each
4610 'cache_dir' directory, but you may specify an alternate
4611 pathname here. Note you must give a full filename, not just
4612 a directory. Since this is the index for the whole object
4613 list you CANNOT periodically rotate it!
4615 If %s can be used in the file name it will be replaced with a
4616 a representation of the cache_dir name where each / is replaced
4617 with '.'. This is needed to allow adding/removing cache_dir
4618 lines when cache_swap_log is being used.
4620 If have more than one 'cache_dir', and %s is not used in the name
4621 these swap logs will have names such as:
4627 The numbered extension (which is added automatically)
4628 corresponds to the order of the 'cache_dir' lines in this
4629 configuration file. If you change the order of the 'cache_dir'
4630 lines in this file, these index files will NOT correspond to
4631 the correct 'cache_dir' entry (unless you manually rename
4632 them). We recommend you do NOT use this option. It is
4633 better to keep these index files in each 'cache_dir' directory.
4636 NAME: logfile_rotate
4639 LOC: Config.Log.rotateNumber
4641 Specifies the default number of logfile rotations to make when you
4642 type 'squid -k rotate'. The default is 10, which will rotate
4643 with extensions 0 through 9. Setting logfile_rotate to 0 will
4644 disable the file name rotation, but the logfiles are still closed
4645 and re-opened. This will enable you to rename the logfiles
4646 yourself just before sending the rotate signal.
4648 Note, from Squid-3.1 this option is only a default for cache.log,
4649 that log can be rotated separately by using debug_options.
4651 Note, from Squid-3.6 this option is only a default for access.log
4652 recorded by stdio: module. Those logs can be rotated separately by
4653 using the rotate=N option on their access_log directive.
4655 Note, the 'squid -k rotate' command normally sends a USR1
4656 signal to the running squid process. In certain situations
4657 (e.g. on Linux with Async I/O), USR1 is used for other
4658 purposes, so -k rotate uses another signal. It is best to get
4659 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4666 DEFAULT: @DEFAULT_MIME_TABLE@
4667 LOC: Config.mimeTablePathname
4669 Path to Squid's icon configuration file.
4671 You shouldn't need to change this, but the default file contains
4672 examples and formatting information if you do.
4678 LOC: Config.onoff.log_mime_hdrs
4681 The Cache can record both the request and the response MIME
4682 headers for each HTTP transaction. The headers are encoded
4683 safely and will appear as two bracketed fields at the end of
4684 the access log (for either the native or httpd-emulated log
4685 formats). To enable this logging set log_mime_hdrs to 'on'.
4690 DEFAULT: @DEFAULT_PID_FILE@
4691 LOC: Config.pidFilename
4693 A filename to write the process-id to. To disable, enter "none".
4696 NAME: client_netmask
4698 LOC: Config.Addrs.client_netmask
4700 DEFAULT_DOC: Log full client IP address
4702 A netmask for client addresses in logfiles and cachemgr output.
4703 Change this to protect the privacy of your cache clients.
4704 A netmask of 255.255.255.0 will log all IP's in that range with
4705 the last digit set to '0'.
4708 NAME: strip_query_terms
4710 LOC: Config.onoff.strip_query_terms
4713 By default, Squid strips query terms from requested URLs before
4714 logging. This protects your user's privacy and reduces log size.
4716 When investigating HIT/MISS or other caching behaviour you
4717 will need to disable this to see the full URL used by Squid.
4724 LOC: Config.onoff.buffered_logs
4726 Whether to write/send access_log records ASAP or accumulate them and
4727 then write/send them in larger chunks. Buffering may improve
4728 performance because it decreases the number of I/Os. However,
4729 buffering increases the delay before log records become available to
4730 the final recipient (e.g., a disk file or logging daemon) and,
4731 hence, increases the risk of log records loss.
4733 Note that even when buffered_logs are off, Squid may have to buffer
4734 records if it cannot write/send them immediately due to pending I/Os
4735 (e.g., the I/O writing the previous log record) or connectivity loss.
4737 Currently honored by 'daemon' and 'tcp' access_log modules only.
4740 NAME: netdb_filename
4742 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4743 LOC: Config.netdbFilename
4746 Where Squid stores it's netdb journal.
4747 When enabled this journal preserves netdb state between restarts.
4749 To disable, enter "none".
4753 OPTIONS FOR TROUBLESHOOTING
4754 -----------------------------------------------------------------------------
4759 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4760 LOC: Debug::cache_log
4762 Squid administrative logging file.
4764 This is where general information about Squid behavior goes. You can
4765 increase the amount of data logged to this file and how often it is
4766 rotated with "debug_options"
4772 DEFAULT_DOC: Log all critical and important messages.
4773 LOC: Debug::debugOptions
4775 Logging options are set as section,level where each source file
4776 is assigned a unique section. Lower levels result in less
4777 output, Full debugging (level 9) can result in a very large
4778 log file, so be careful.
4780 The magic word "ALL" sets debugging levels for all sections.
4781 The default is to run with "ALL,1" to record important warnings.
4783 The rotate=N option can be used to keep more or less of these logs
4784 than would otherwise be kept by logfile_rotate.
4785 For most uses a single log should be enough to monitor current
4786 events affecting Squid.
4791 LOC: Config.coredump_dir
4792 DEFAULT_IF_NONE: none
4793 DEFAULT_DOC: Use the directory from where Squid was started.
4795 By default Squid leaves core files in the directory from where
4796 it was started. If you set 'coredump_dir' to a directory
4797 that exists, Squid will chdir() to that directory at startup
4798 and coredump files will be left there.
4802 # Leave coredumps in the first cache dir
4803 coredump_dir @DEFAULT_SWAP_DIR@
4809 OPTIONS FOR FTP GATEWAYING
4810 -----------------------------------------------------------------------------
4816 LOC: Config.Ftp.anon_user
4818 If you want the anonymous login password to be more informative
4819 (and enable the use of picky FTP servers), set this to something
4820 reasonable for your domain, like wwwuser@somewhere.net
4822 The reason why this is domainless by default is the
4823 request can be made on the behalf of a user in any domain,
4824 depending on how the cache is used.
4825 Some FTP server also validate the email address is valid
4826 (for example perl.com).
4832 LOC: Config.Ftp.passive
4834 If your firewall does not allow Squid to use passive
4835 connections, turn off this option.
4837 Use of ftp_epsv_all option requires this to be ON.
4843 LOC: Config.Ftp.epsv_all
4845 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4847 NATs may be able to put the connection on a "fast path" through the
4848 translator, as the EPRT command will never be used and therefore,
4849 translation of the data portion of the segments will never be needed.
4851 When a client only expects to do two-way FTP transfers this may be
4853 If squid finds that it must do a three-way FTP transfer after issuing
4854 an EPSV ALL command, the FTP session will fail.
4856 If you have any doubts about this option do not use it.
4857 Squid will nicely attempt all other connection methods.
4859 Requires ftp_passive to be ON (default) for any effect.
4865 LOC: Config.accessList.ftp_epsv
4867 FTP Protocol extensions permit the use of a special "EPSV" command.
4869 NATs may be able to put the connection on a "fast path" through the
4870 translator using EPSV, as the EPRT command will never be used
4871 and therefore, translation of the data portion of the segments
4872 will never be needed.
4874 EPSV is often required to interoperate with FTP servers on IPv6
4875 networks. On the other hand, it may break some IPv4 servers.
4877 By default, EPSV may try EPSV with any FTP server. To fine tune
4878 that decision, you may restrict EPSV to certain clients or servers
4881 ftp_epsv allow|deny al1 acl2 ...
4883 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
4885 Only fast ACLs are supported.
4886 Requires ftp_passive to be ON (default) for any effect.
4892 LOC: Config.Ftp.eprt
4894 FTP Protocol extensions permit the use of a special "EPRT" command.
4896 This extension provides a protocol neutral alternative to the
4897 IPv4-only PORT command. When supported it enables active FTP data
4898 channels over IPv6 and efficient NAT handling.
4900 Turning this OFF will prevent EPRT being attempted and will skip
4901 straight to using PORT for IPv4 servers.
4903 Some devices are known to not handle this extension correctly and
4904 may result in crashes. Devices which suport EPRT enough to fail
4905 cleanly will result in Squid attempting PORT anyway. This directive
4906 should only be disabled when EPRT results in device failures.
4908 WARNING: Doing so will convert Squid back to the old behavior with all
4909 the related problems with external NAT devices/layers and IPv4-only FTP.
4912 NAME: ftp_sanitycheck
4915 LOC: Config.Ftp.sanitycheck
4917 For security and data integrity reasons Squid by default performs
4918 sanity checks of the addresses of FTP data connections ensure the
4919 data connection is to the requested server. If you need to allow
4920 FTP connections to servers using another IP address for the data
4921 connection turn this off.
4924 NAME: ftp_telnet_protocol
4927 LOC: Config.Ftp.telnet
4929 The FTP protocol is officially defined to use the telnet protocol
4930 as transport channel for the control connection. However, many
4931 implementations are broken and does not respect this aspect of
4934 If you have trouble accessing files with ASCII code 255 in the
4935 path or similar problems involving this ASCII code you can
4936 try setting this directive to off. If that helps, report to the
4937 operator of the FTP server in question that their FTP server
4938 is broken and does not follow the FTP standard.
4942 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4943 -----------------------------------------------------------------------------
4948 DEFAULT: @DEFAULT_DISKD@
4949 LOC: Config.Program.diskd
4951 Specify the location of the diskd executable.
4952 Note this is only useful if you have compiled in
4953 diskd as one of the store io modules.
4956 NAME: unlinkd_program
4959 DEFAULT: @DEFAULT_UNLINKD@
4960 LOC: Config.Program.unlinkd
4962 Specify the location of the executable for file deletion process.
4965 NAME: pinger_program
4968 DEFAULT: @DEFAULT_PINGER@
4971 Specify the location of the executable for the pinger process.
4980 Control whether the pinger is active at run-time.
4981 Enables turning ICMP pinger on and off with a simple
4982 squid -k reconfigure.
4987 OPTIONS FOR URL REWRITING
4988 -----------------------------------------------------------------------------
4991 NAME: url_rewrite_program redirect_program
4993 LOC: Config.Program.redirect
4996 Specify the location of the executable URL rewriter to use.
4997 Since they can perform almost any function there isn't one included.
4999 For each requested URL, the rewriter will receive on line with the format
5001 [channel-ID <SP>] URL [<SP> extras]<NL>
5003 See url_rewrite_extras on how to send "extras" with optional values to
5005 After processing the request the helper must reply using the following format:
5007 [channel-ID <SP>] result [<SP> kv-pairs]
5009 The result code can be:
5011 OK status=30N url="..."
5012 Redirect the URL to the one supplied in 'url='.
5013 'status=' is optional and contains the status code to send
5014 the client in Squids HTTP response. It must be one of the
5015 HTTP redirect status codes: 301, 302, 303, 307, 308.
5016 When no status is given Squid will use 302.
5018 OK rewrite-url="..."
5019 Rewrite the URL to the one supplied in 'rewrite-url='.
5020 The new URL is fetched directly by Squid and returned to
5021 the client as the response to its request.
5024 When neither of url= and rewrite-url= are sent Squid does
5028 Do not change the URL.
5031 An internal error occurred in the helper, preventing
5032 a result being identified. The 'message=' key name is
5033 reserved for delivering a log message.
5036 In addition to the above kv-pairs Squid also understands the following
5037 optional kv-pairs received from URL rewriters:
5039 Associates a TAG with the client TCP connection.
5040 The TAG is treated as a regular annotation but persists across
5041 future requests on the client connection rather than just the
5042 current request. A helper may update the TAG during subsequent
5043 requests be returning a new kv-pair.
5045 When using the concurrency= option the protocol is changed by
5046 introducing a query channel tag in front of the request/response.
5047 The query channel tag is a number between 0 and concurrency-1.
5048 This value must be echoed back unchanged to Squid as the first part
5049 of the response relating to its request.
5051 WARNING: URL re-writing ability should be avoided whenever possible.
5052 Use the URL redirect form of response instead.
5054 Re-write creates a difference in the state held by the client
5055 and server. Possibly causing confusion when the server response
5056 contains snippets of its view state. Embeded URLs, response
5057 and content Location headers, etc. are not re-written by this
5060 By default, a URL rewriter is not used.
5063 NAME: url_rewrite_children redirect_children
5064 TYPE: HelperChildConfig
5065 DEFAULT: 20 startup=0 idle=1 concurrency=0
5066 LOC: Config.redirectChildren
5068 The maximum number of redirector processes to spawn. If you limit
5069 it too few Squid will have to wait for them to process a backlog of
5070 URLs, slowing it down. If you allow too many they will use RAM
5071 and other system resources noticably.
5073 The startup= and idle= options allow some measure of skew in your
5078 Sets a minimum of how many processes are to be spawned when Squid
5079 starts or reconfigures. When set to zero the first request will
5080 cause spawning of the first child process to handle it.
5082 Starting too few will cause an initial slowdown in traffic as Squid
5083 attempts to simultaneously spawn enough processes to cope.
5087 Sets a minimum of how many processes Squid is to try and keep available
5088 at all times. When traffic begins to rise above what the existing
5089 processes can handle this many more will be spawned up to the maximum
5090 configured. A minimum setting of 1 is required.
5094 The number of requests each redirector helper can handle in
5095 parallel. Defaults to 0 which indicates the redirector
5096 is a old-style single threaded redirector.
5098 When this directive is set to a value >= 1 then the protocol
5099 used to communicate with the helper is modified to include
5100 an ID in front of the request/response. The ID from the request
5101 must be echoed back with the response to that request.
5105 Sets the maximum number of queued requests.
5106 If the queued requests exceed queue size and redirector_bypass
5107 configuration option is set, then redirector is bypassed. Otherwise, if
5108 overloading persists squid may abort its operation.
5109 The default value is set to 2*numberofchildren.
5112 NAME: url_rewrite_host_header redirect_rewrites_host_header
5115 LOC: Config.onoff.redir_rewrites_host
5117 To preserve same-origin security policies in browsers and
5118 prevent Host: header forgery by redirectors Squid rewrites
5119 any Host: header in redirected requests.
5121 If you are running an accelerator this may not be a wanted
5122 effect of a redirector. This directive enables you disable
5123 Host: alteration in reverse-proxy traffic.
5125 WARNING: Entries are cached on the result of the URL rewriting
5126 process, so be careful if you have domain-virtual hosts.
5128 WARNING: Squid and other software verifies the URL and Host
5129 are matching, so be careful not to relay through other proxies
5130 or inspecting firewalls with this disabled.
5133 NAME: url_rewrite_access redirector_access
5136 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5137 LOC: Config.accessList.redirector
5139 If defined, this access list specifies which requests are
5140 sent to the redirector processes.
5142 This clause supports both fast and slow acl types.
5143 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5146 NAME: url_rewrite_bypass redirector_bypass
5148 LOC: Config.onoff.redirector_bypass
5151 When this is 'on', a request will not go through the
5152 redirector if all the helpers are busy. If this is 'off'
5153 and the redirector queue grows too large, Squid will exit
5154 with a FATAL error and ask you to increase the number of
5155 redirectors. You should only enable this if the redirectors
5156 are not critical to your caching system. If you use
5157 redirectors for access control, and you enable this option,
5158 users may have access to pages they should not
5159 be allowed to request.
5160 This options sets default queue-size option of the url_rewrite_children
5164 NAME: url_rewrite_extras
5165 TYPE: TokenOrQuotedString
5166 LOC: Config.redirector_extras
5167 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5169 Specifies a string to be append to request line format for the
5170 rewriter helper. "Quoted" format values may contain spaces and
5171 logformat %macros. In theory, any logformat %macro can be used.
5172 In practice, a %macro expands as a dash (-) if the helper request is
5173 sent before the required macro information is available to Squid.
5176 NAME: url_rewrite_timeout
5177 TYPE: UrlHelperTimeout
5178 LOC: Config.onUrlRewriteTimeout
5180 DEFAULT_DOC: Squid waits for the helper response forever
5182 Squid times active requests to redirector. The timeout value and Squid
5183 reaction to a timed out request are configurable using the following
5186 url_rewrite_timeout timeout time-units on_timeout=<action> [response=<quoted-response>]
5188 supported timeout actions:
5189 fail Squid return a ERR_GATEWAY_FAILURE error page
5191 bypass Do not re-write the URL
5193 retry Send the lookup to the helper again
5195 use_configured_response
5196 Use the <quoted-response> as helper response
5200 OPTIONS FOR STORE ID
5201 -----------------------------------------------------------------------------
5204 NAME: store_id_program storeurl_rewrite_program
5206 LOC: Config.Program.store_id
5209 Specify the location of the executable StoreID helper to use.
5210 Since they can perform almost any function there isn't one included.
5212 For each requested URL, the helper will receive one line with the format
5214 [channel-ID <SP>] URL [<SP> extras]<NL>
5217 After processing the request the helper must reply using the following format:
5219 [channel-ID <SP>] result [<SP> kv-pairs]
5221 The result code can be:
5224 Use the StoreID supplied in 'store-id='.
5227 The default is to use HTTP request URL as the store ID.
5230 An internal error occured in the helper, preventing
5231 a result being identified.
5233 In addition to the above kv-pairs Squid also understands the following
5234 optional kv-pairs received from URL rewriters:
5236 Associates a TAG with the client TCP connection.
5237 Please see url_rewrite_program related documentation for this
5240 Helper programs should be prepared to receive and possibly ignore
5241 additional whitespace-separated tokens on each input line.
5243 When using the concurrency= option the protocol is changed by
5244 introducing a query channel tag in front of the request/response.
5245 The query channel tag is a number between 0 and concurrency-1.
5246 This value must be echoed back unchanged to Squid as the first part
5247 of the response relating to its request.
5249 NOTE: when using StoreID refresh_pattern will apply to the StoreID
5250 returned from the helper and not the URL.
5252 WARNING: Wrong StoreID value returned by a careless helper may result
5253 in the wrong cached response returned to the user.
5255 By default, a StoreID helper is not used.
5258 NAME: store_id_extras
5259 TYPE: TokenOrQuotedString
5260 LOC: Config.storeId_extras
5261 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5263 Specifies a string to be append to request line format for the
5264 StoreId helper. "Quoted" format values may contain spaces and
5265 logformat %macros. In theory, any logformat %macro can be used.
5266 In practice, a %macro expands as a dash (-) if the helper request is
5267 sent before the required macro information is available to Squid.
5270 NAME: store_id_children storeurl_rewrite_children
5271 TYPE: HelperChildConfig
5272 DEFAULT: 20 startup=0 idle=1 concurrency=0
5273 LOC: Config.storeIdChildren
5275 The maximum number of StoreID helper processes to spawn. If you limit
5276 it too few Squid will have to wait for them to process a backlog of
5277 requests, slowing it down. If you allow too many they will use RAM
5278 and other system resources noticably.
5280 The startup= and idle= options allow some measure of skew in your
5285 Sets a minimum of how many processes are to be spawned when Squid
5286 starts or reconfigures. When set to zero the first request will
5287 cause spawning of the first child process to handle it.
5289 Starting too few will cause an initial slowdown in traffic as Squid
5290 attempts to simultaneously spawn enough processes to cope.
5294 Sets a minimum of how many processes Squid is to try and keep available
5295 at all times. When traffic begins to rise above what the existing
5296 processes can handle this many more will be spawned up to the maximum
5297 configured. A minimum setting of 1 is required.
5301 The number of requests each storeID helper can handle in
5302 parallel. Defaults to 0 which indicates the helper
5303 is a old-style single threaded program.
5305 When this directive is set to a value >= 1 then the protocol
5306 used to communicate with the helper is modified to include
5307 an ID in front of the request/response. The ID from the request
5308 must be echoed back with the response to that request.
5312 Sets the maximum number of queued requests.
5313 If the queued requests exceed queue size and store_id_bypass
5314 configuration option is set, then storeID helper is bypassed. Otherwise,
5315 if overloading persists squid may abort its operation.
5316 The default value is set to 2*numberofchildren.
5319 NAME: store_id_access storeurl_rewrite_access
5322 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5323 LOC: Config.accessList.store_id
5325 If defined, this access list specifies which requests are
5326 sent to the StoreID processes. By default all requests
5329 This clause supports both fast and slow acl types.
5330 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5333 NAME: store_id_bypass storeurl_rewrite_bypass
5335 LOC: Config.onoff.store_id_bypass
5338 When this is 'on', a request will not go through the
5339 helper if all helpers are busy. If this is 'off'
5340 and the helper queue grows too large, Squid will exit
5341 with a FATAL error and ask you to increase the number of
5342 helpers. You should only enable this if the helperss
5343 are not critical to your caching system. If you use
5344 helpers for critical caching components, and you enable this
5345 option, users may not get objects from cache.
5346 This options sets default queue-size option of the store_id_children
5351 OPTIONS FOR TUNING THE CACHE
5352 -----------------------------------------------------------------------------
5355 NAME: cache no_cache
5358 DEFAULT_DOC: By default, this directive is unused and has no effect.
5359 LOC: Config.accessList.noCache
5361 Requests denied by this directive will not be served from the cache
5362 and their responses will not be stored in the cache. This directive
5363 has no effect on other transactions and on already cached responses.
5365 This clause supports both fast and slow acl types.
5366 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5368 This and the two other similar caching directives listed below are
5369 checked at different transaction processing stages, have different
5370 access to response information, affect different cache operations,
5371 and differ in slow ACLs support:
5373 * cache: Checked before Squid makes a hit/miss determination.
5374 No access to reply information!
5375 Denies both serving a hit and storing a miss.
5376 Supports both fast and slow ACLs.
5377 * send_hit: Checked after a hit was detected.
5378 Has access to reply (hit) information.
5379 Denies serving a hit only.
5380 Supports fast ACLs only.
5381 * store_miss: Checked before storing a cachable miss.
5382 Has access to reply (miss) information.
5383 Denies storing a miss only.
5384 Supports fast ACLs only.
5386 If you are not sure which of the three directives to use, apply the
5387 following decision logic:
5389 * If your ACL(s) are of slow type _and_ need response info, redesign.
5390 Squid does not support that particular combination at this time.
5392 * If your directive ACL(s) are of slow type, use "cache"; and/or
5393 * if your directive ACL(s) need no response info, use "cache".
5395 * If you do not want the response cached, use store_miss; and/or
5396 * if you do not want a hit on a cached response, use send_hit.
5402 DEFAULT_DOC: By default, this directive is unused and has no effect.
5403 LOC: Config.accessList.sendHit
5405 Responses denied by this directive will not be served from the cache
5406 (but may still be cached, see store_miss). This directive has no
5407 effect on the responses it allows and on the cached objects.
5409 Please see the "cache" directive for a summary of differences among
5410 store_miss, send_hit, and cache directives.
5412 Unlike the "cache" directive, send_hit only supports fast acl
5413 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5417 # apply custom Store ID mapping to some URLs
5418 acl MapMe dstdomain .c.example.com
5419 store_id_program ...
5420 store_id_access allow MapMe
5422 # but prevent caching of special responses
5423 # such as 302 redirects that cause StoreID loops
5424 acl Ordinary http_status 200-299
5425 store_miss deny MapMe !Ordinary
5427 # and do not serve any previously stored special responses
5428 # from the cache (in case they were already cached before
5429 # the above store_miss rule was in effect).
5430 send_hit deny MapMe !Ordinary
5436 DEFAULT_DOC: By default, this directive is unused and has no effect.
5437 LOC: Config.accessList.storeMiss
5439 Responses denied by this directive will not be cached (but may still
5440 be served from the cache, see send_hit). This directive has no
5441 effect on the responses it allows and on the already cached responses.
5443 Please see the "cache" directive for a summary of differences among
5444 store_miss, send_hit, and cache directives. See the
5445 send_hit directive for a usage example.
5447 Unlike the "cache" directive, store_miss only supports fast acl
5448 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5454 LOC: Config.maxStale
5457 This option puts an upper limit on how stale content Squid
5458 will serve from the cache if cache validation fails.
5459 Can be overriden by the refresh_pattern max-stale option.
5462 NAME: refresh_pattern
5463 TYPE: refreshpattern
5467 usage: refresh_pattern [-i] regex min percent max [options]
5469 By default, regular expressions are CASE-SENSITIVE. To make
5470 them case-insensitive, use the -i option.
5472 'Min' is the time (in minutes) an object without an explicit
5473 expiry time should be considered fresh. The recommended
5474 value is 0, any higher values may cause dynamic applications
5475 to be erroneously cached unless the application designer
5476 has taken the appropriate actions.
5478 'Percent' is a percentage of the objects age (time since last
5479 modification age) an object without explicit expiry time
5480 will be considered fresh.
5482 'Max' is an upper limit on how long objects without an explicit
5483 expiry time will be considered fresh.
5485 options: override-expire
5495 override-expire enforces min age even if the server
5496 sent an explicit expiry time (e.g., with the
5497 Expires: header or Cache-Control: max-age). Doing this
5498 VIOLATES the HTTP standard. Enabling this feature
5499 could make you liable for problems which it causes.
5501 Note: override-expire does not enforce staleness - it only extends
5502 freshness / min. If the server returns a Expires time which
5503 is longer than your max time, Squid will still consider
5504 the object fresh for that period of time.
5506 override-lastmod enforces min age even on objects
5507 that were modified recently.
5509 reload-into-ims changes a client no-cache or ``reload''
5510 request for a cached entry into a conditional request using
5511 If-Modified-Since and/or If-None-Match headers, provided the
5512 cached entry has a Last-Modified and/or a strong ETag header.
5513 Doing this VIOLATES the HTTP standard. Enabling this feature
5514 could make you liable for problems which it causes.
5516 ignore-reload ignores a client no-cache or ``reload''
5517 header. Doing this VIOLATES the HTTP standard. Enabling
5518 this feature could make you liable for problems which
5521 ignore-no-store ignores any ``Cache-control: no-store''
5522 headers received from a server. Doing this VIOLATES
5523 the HTTP standard. Enabling this feature could make you
5524 liable for problems which it causes.
5526 ignore-private ignores any ``Cache-control: private''
5527 headers received from a server. Doing this VIOLATES
5528 the HTTP standard. Enabling this feature could make you
5529 liable for problems which it causes.
5531 refresh-ims causes squid to contact the origin server
5532 when a client issues an If-Modified-Since request. This
5533 ensures that the client will receive an updated version
5534 if one is available.
5536 store-stale stores responses even if they don't have explicit
5537 freshness or a validator (i.e., Last-Modified or an ETag)
5538 present, or if they're already stale. By default, Squid will
5539 not cache such responses because they usually can't be
5540 reused. Note that such responses will be stale by default.
5542 max-stale=NN provide a maximum staleness factor. Squid won't
5543 serve objects more stale than this even if it failed to
5544 validate the object. Default: use the max_stale global limit.
5546 Basically a cached object is:
5548 FRESH if expire > now, else STALE
5550 FRESH if lm-factor < percent, else STALE
5554 The refresh_pattern lines are checked in the order listed here.
5555 The first entry which matches is used. If none of the entries
5556 match the default will be used.
5558 Note, you must uncomment all the default lines if you want
5559 to change one. The default setting is only active if none is
5565 # Add any of your own refresh_pattern entries above these.
5567 refresh_pattern ^ftp: 1440 20% 10080
5568 refresh_pattern ^gopher: 1440 0% 1440
5569 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5570 refresh_pattern . 0 20% 4320
5574 NAME: quick_abort_min
5578 LOC: Config.quickAbort.min
5581 NAME: quick_abort_max
5585 LOC: Config.quickAbort.max
5588 NAME: quick_abort_pct
5592 LOC: Config.quickAbort.pct
5594 The cache by default continues downloading aborted requests
5595 which are almost completed (less than 16 KB remaining). This
5596 may be undesirable on slow (e.g. SLIP) links and/or very busy
5597 caches. Impatient users may tie up file descriptors and
5598 bandwidth by repeatedly requesting and immediately aborting
5601 When the user aborts a request, Squid will check the
5602 quick_abort values to the amount of data transferred until
5605 If the transfer has less than 'quick_abort_min' KB remaining,
5606 it will finish the retrieval.
5608 If the transfer has more than 'quick_abort_max' KB remaining,
5609 it will abort the retrieval.
5611 If more than 'quick_abort_pct' of the transfer has completed,
5612 it will finish the retrieval.
5614 If you do not want any retrieval to continue after the client
5615 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5618 If you want retrievals to always continue if they are being
5619 cached set 'quick_abort_min' to '-1 KB'.
5622 NAME: read_ahead_gap
5623 COMMENT: buffer-size
5625 LOC: Config.readAheadGap
5628 The amount of data the cache will buffer ahead of what has been
5629 sent to the client when retrieving an object from another server.
5633 IFDEF: USE_HTTP_VIOLATIONS
5636 LOC: Config.negativeTtl
5639 Set the Default Time-to-Live (TTL) for failed requests.
5640 Certain types of failures (such as "connection refused" and
5641 "404 Not Found") are able to be negatively-cached for a short time.
5642 Modern web servers should provide Expires: header, however if they
5643 do not this can provide a minimum TTL.
5644 The default is not to cache errors with unknown expiry details.
5646 Note that this is different from negative caching of DNS lookups.
5648 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5649 this feature could make you liable for problems which it
5653 NAME: positive_dns_ttl
5656 LOC: Config.positiveDnsTtl
5659 Upper limit on how long Squid will cache positive DNS responses.
5660 Default is 6 hours (360 minutes). This directive must be set
5661 larger than negative_dns_ttl.
5664 NAME: negative_dns_ttl
5667 LOC: Config.negativeDnsTtl
5670 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5671 This also sets the lower cache limit on positive lookups.
5672 Minimum value is 1 second, and it is not recommendable to go
5673 much below 10 seconds.
5676 NAME: range_offset_limit
5677 COMMENT: size [acl acl...]
5679 LOC: Config.rangeOffsetLimit
5682 usage: (size) [units] [[!]aclname]
5684 Sets an upper limit on how far (number of bytes) into the file
5685 a Range request may be to cause Squid to prefetch the whole file.
5686 If beyond this limit, Squid forwards the Range request as it is and
5687 the result is NOT cached.
5689 This is to stop a far ahead range request (lets say start at 17MB)
5690 from making Squid fetch the whole object up to that point before
5691 sending anything to the client.
5693 Multiple range_offset_limit lines may be specified, and they will
5694 be searched from top to bottom on each request until a match is found.
5695 The first match found will be used. If no line matches a request, the
5696 default limit of 0 bytes will be used.
5698 'size' is the limit specified as a number of units.
5700 'units' specifies whether to use bytes, KB, MB, etc.
5701 If no units are specified bytes are assumed.
5703 A size of 0 causes Squid to never fetch more than the
5704 client requested. (default)
5706 A size of 'none' causes Squid to always fetch the object from the
5707 beginning so it may cache the result. (2.0 style)
5709 'aclname' is the name of a defined ACL.
5711 NP: Using 'none' as the byte value here will override any quick_abort settings
5712 that may otherwise apply to the range request. The range request will
5713 be fully fetched from start to finish regardless of the client
5714 actions. This affects bandwidth usage.
5717 NAME: minimum_expiry_time
5720 LOC: Config.minimum_expiry_time
5723 The minimum caching time according to (Expires - Date)
5724 headers Squid honors if the object can't be revalidated.
5725 The default is 60 seconds.
5727 In reverse proxy environments it might be desirable to honor
5728 shorter object lifetimes. It is most likely better to make
5729 your server return a meaningful Last-Modified header however.
5731 In ESI environments where page fragments often have short
5732 lifetimes, this will often be best set to 0.
5735 NAME: store_avg_object_size
5739 LOC: Config.Store.avgObjectSize
5741 Average object size, used to estimate number of objects your
5742 cache can hold. The default is 13 KB.
5744 This is used to pre-seed the cache index memory allocation to
5745 reduce expensive reallocate operations while handling clients
5746 traffic. Too-large values may result in memory allocation during
5747 peak traffic, too-small values will result in wasted memory.
5749 Check the cache manager 'info' report metrics for the real
5750 object sizes seen by your Squid before tuning this.
5753 NAME: store_objects_per_bucket
5756 LOC: Config.Store.objectsPerBucket
5758 Target number of objects per bucket in the store hash table.
5759 Lowering this value increases the total number of buckets and
5760 also the storage maintenance rate. The default is 20.
5765 -----------------------------------------------------------------------------
5768 NAME: request_header_max_size
5772 LOC: Config.maxRequestHeaderSize
5774 This specifies the maximum size for HTTP headers in a request.
5775 Request headers are usually relatively small (about 512 bytes).
5776 Placing a limit on the request header size will catch certain
5777 bugs (for example with persistent connections) and possibly
5778 buffer-overflow or denial-of-service attacks.
5781 NAME: reply_header_max_size
5785 LOC: Config.maxReplyHeaderSize
5787 This specifies the maximum size for HTTP headers in a reply.
5788 Reply headers are usually relatively small (about 512 bytes).
5789 Placing a limit on the reply header size will catch certain
5790 bugs (for example with persistent connections) and possibly
5791 buffer-overflow or denial-of-service attacks.
5794 NAME: request_body_max_size
5798 DEFAULT_DOC: No limit.
5799 LOC: Config.maxRequestBodySize
5801 This specifies the maximum size for an HTTP request body.
5802 In other words, the maximum size of a PUT/POST request.
5803 A user who attempts to send a request with a body larger
5804 than this limit receives an "Invalid Request" error message.
5805 If you set this parameter to a zero (the default), there will
5806 be no limit imposed.
5808 See also client_request_buffer_max_size for an alternative
5809 limitation on client uploads which can be configured.
5812 NAME: client_request_buffer_max_size
5816 LOC: Config.maxRequestBufferSize
5818 This specifies the maximum buffer size of a client request.
5819 It prevents squid eating too much memory when somebody uploads
5824 IFDEF: USE_HTTP_VIOLATIONS
5827 DEFAULT_DOC: Obey RFC 2616.
5828 LOC: Config.accessList.brokenPosts
5830 A list of ACL elements which, if matched, causes Squid to send
5831 an extra CRLF pair after the body of a PUT/POST request.
5833 Some HTTP servers has broken implementations of PUT/POST,
5834 and rely on an extra CRLF pair sent by some WWW clients.
5836 Quote from RFC2616 section 4.1 on this matter:
5838 Note: certain buggy HTTP/1.0 client implementations generate an
5839 extra CRLF's after a POST request. To restate what is explicitly
5840 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5841 a request with an extra CRLF.
5843 This clause only supports fast acl types.
5844 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5847 acl buggy_server url_regex ^http://....
5848 broken_posts allow buggy_server
5851 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5854 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5856 LOC: Adaptation::Config::use_indirect_client
5858 Controls whether the indirect client IP address (instead of the direct
5859 client IP address) is passed to adaptation services.
5861 See also: follow_x_forwarded_for adaptation_send_client_ip
5865 IFDEF: USE_HTTP_VIOLATIONS
5869 LOC: Config.onoff.via
5871 If set (default), Squid will include a Via header in requests and
5872 replies as required by RFC2616.
5878 LOC: Config.onoff.ie_refresh
5881 Microsoft Internet Explorer up until version 5.5 Service
5882 Pack 1 has an issue with transparent proxies, wherein it
5883 is impossible to force a refresh. Turning this on provides
5884 a partial fix to the problem, by causing all IMS-REFRESH
5885 requests from older IE versions to check the origin server
5886 for fresh content. This reduces hit ratio by some amount
5887 (~10% in my experience), but allows users to actually get
5888 fresh content when they want it. Note because Squid
5889 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5890 of 5.5 is unchanged from old versions of Squid (i.e. a
5891 forced refresh is impossible). Newer versions of IE will,
5892 hopefully, continue to have the new behavior and will be
5893 handled based on that assumption. This option defaults to
5894 the old Squid behavior, which is better for hit ratios but
5895 worse for clients using IE, if they need to be able to
5896 force fresh content.
5899 NAME: vary_ignore_expire
5902 LOC: Config.onoff.vary_ignore_expire
5905 Many HTTP servers supporting Vary gives such objects
5906 immediate expiry time with no cache-control header
5907 when requested by a HTTP/1.0 client. This option
5908 enables Squid to ignore such expiry times until
5909 HTTP/1.1 is fully implemented.
5911 WARNING: If turned on this may eventually cause some
5912 varying objects not intended for caching to get cached.
5915 NAME: request_entities
5917 LOC: Config.onoff.request_entities
5920 Squid defaults to deny GET and HEAD requests with request entities,
5921 as the meaning of such requests are undefined in the HTTP standard
5922 even if not explicitly forbidden.
5924 Set this directive to on if you have clients which insists
5925 on sending request entities in GET or HEAD requests. But be warned
5926 that there is server software (both proxies and web servers) which
5927 can fail to properly process this kind of request which may make you
5928 vulnerable to cache pollution attacks if enabled.
5931 NAME: request_header_access
5932 IFDEF: USE_HTTP_VIOLATIONS
5933 TYPE: http_header_access
5934 LOC: Config.request_header_access
5936 DEFAULT_DOC: No limits.
5938 Usage: request_header_access header_name allow|deny [!]aclname ...
5940 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5941 this feature could make you liable for problems which it
5944 This option replaces the old 'anonymize_headers' and the
5945 older 'http_anonymizer' option with something that is much
5946 more configurable. A list of ACLs for each header name allows
5947 removal of specific header fields under specific conditions.
5949 This option only applies to outgoing HTTP request headers (i.e.,
5950 headers sent by Squid to the next HTTP hop such as a cache peer
5951 or an origin server). The option has no effect during cache hit
5952 detection. The equivalent adaptation vectoring point in ICAP
5953 terminology is post-cache REQMOD.
5955 The option is applied to individual outgoing request header
5956 fields. For each request header field F, Squid uses the first
5957 qualifying sets of request_header_access rules:
5959 1. Rules with header_name equal to F's name.
5960 2. Rules with header_name 'Other', provided F's name is not
5961 on the hard-coded list of commonly used HTTP header names.
5962 3. Rules with header_name 'All'.
5964 Within that qualifying rule set, rule ACLs are checked as usual.
5965 If ACLs of an "allow" rule match, the header field is allowed to
5966 go through as is. If ACLs of a "deny" rule match, the header is
5967 removed and request_header_replace is then checked to identify
5968 if the removed header has a replacement. If no rules within the
5969 set have matching ACLs, the header field is left as is.
5971 For example, to achieve the same behavior as the old
5972 'http_anonymizer standard' option, you should use:
5974 request_header_access From deny all
5975 request_header_access Referer deny all
5976 request_header_access User-Agent deny all
5978 Or, to reproduce the old 'http_anonymizer paranoid' feature
5981 request_header_access Authorization allow all
5982 request_header_access Proxy-Authorization allow all
5983 request_header_access Cache-Control allow all
5984 request_header_access Content-Length allow all
5985 request_header_access Content-Type allow all
5986 request_header_access Date allow all
5987 request_header_access Host allow all
5988 request_header_access If-Modified-Since allow all
5989 request_header_access Pragma allow all
5990 request_header_access Accept allow all
5991 request_header_access Accept-Charset allow all
5992 request_header_access Accept-Encoding allow all
5993 request_header_access Accept-Language allow all
5994 request_header_access Connection allow all
5995 request_header_access All deny all
5997 HTTP reply headers are controlled with the reply_header_access directive.
5999 By default, all headers are allowed (no anonymizing is performed).
6002 NAME: reply_header_access
6003 IFDEF: USE_HTTP_VIOLATIONS
6004 TYPE: http_header_access
6005 LOC: Config.reply_header_access
6007 DEFAULT_DOC: No limits.
6009 Usage: reply_header_access header_name allow|deny [!]aclname ...
6011 WARNING: Doing this VIOLATES the HTTP standard. Enabling
6012 this feature could make you liable for problems which it
6015 This option only applies to reply headers, i.e., from the
6016 server to the client.
6018 This is the same as request_header_access, but in the other
6019 direction. Please see request_header_access for detailed
6022 For example, to achieve the same behavior as the old
6023 'http_anonymizer standard' option, you should use:
6025 reply_header_access Server deny all
6026 reply_header_access WWW-Authenticate deny all
6027 reply_header_access Link deny all
6029 Or, to reproduce the old 'http_anonymizer paranoid' feature
6032 reply_header_access Allow allow all
6033 reply_header_access WWW-Authenticate allow all
6034 reply_header_access Proxy-Authenticate allow all
6035 reply_header_access Cache-Control allow all
6036 reply_header_access Content-Encoding allow all
6037 reply_header_access Content-Length allow all
6038 reply_header_access Content-Type allow all
6039 reply_header_access Date allow all
6040 reply_header_access Expires allow all
6041 reply_header_access Last-Modified allow all
6042 reply_header_access Location allow all
6043 reply_header_access Pragma allow all
6044 reply_header_access Content-Language allow all
6045 reply_header_access Retry-After allow all
6046 reply_header_access Title allow all
6047 reply_header_access Content-Disposition allow all
6048 reply_header_access Connection allow all
6049 reply_header_access All deny all
6051 HTTP request headers are controlled with the request_header_access directive.
6053 By default, all headers are allowed (no anonymizing is
6057 NAME: request_header_replace header_replace
6058 IFDEF: USE_HTTP_VIOLATIONS
6059 TYPE: http_header_replace
6060 LOC: Config.request_header_access
6063 Usage: request_header_replace header_name message
6064 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
6066 This option allows you to change the contents of headers
6067 denied with request_header_access above, by replacing them
6068 with some fixed string.
6070 This only applies to request headers, not reply headers.
6072 By default, headers are removed if denied.
6075 NAME: reply_header_replace
6076 IFDEF: USE_HTTP_VIOLATIONS
6077 TYPE: http_header_replace
6078 LOC: Config.reply_header_access
6081 Usage: reply_header_replace header_name message
6082 Example: reply_header_replace Server Foo/1.0
6084 This option allows you to change the contents of headers
6085 denied with reply_header_access above, by replacing them
6086 with some fixed string.
6088 This only applies to reply headers, not request headers.
6090 By default, headers are removed if denied.
6093 NAME: request_header_add
6094 TYPE: HeaderWithAclList
6095 LOC: Config.request_header_add
6098 Usage: request_header_add field-name field-value acl1 [acl2] ...
6099 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
6101 This option adds header fields to outgoing HTTP requests (i.e.,
6102 request headers sent by Squid to the next HTTP hop such as a
6103 cache peer or an origin server). The option has no effect during
6104 cache hit detection. The equivalent adaptation vectoring point
6105 in ICAP terminology is post-cache REQMOD.
6107 Field-name is a token specifying an HTTP header name. If a
6108 standard HTTP header name is used, Squid does not check whether
6109 the new header conflicts with any existing headers or violates
6110 HTTP rules. If the request to be modified already contains a
6111 field with the same name, the old field is preserved but the
6112 header field values are not merged.
6114 Field-value is either a token or a quoted string. If quoted
6115 string format is used, then the surrounding quotes are removed
6116 while escape sequences and %macros are processed.
6118 In theory, all of the logformat codes can be used as %macros.
6119 However, unlike logging (which happens at the very end of
6120 transaction lifetime), the transaction may not yet have enough
6121 information to expand a macro when the new header value is needed.
6122 And some information may already be available to Squid but not yet
6123 committed where the macro expansion code can access it (report
6124 such instances!). The macro will be expanded into a single dash
6125 ('-') in such cases. Not all macros have been tested.
6127 One or more Squid ACLs may be specified to restrict header
6128 injection to matching requests. As always in squid.conf, all
6129 ACLs in an option ACL list must be satisfied for the insertion
6130 to happen. The request_header_add option supports fast ACLs
6139 This option used to log custom information about the master
6140 transaction. For example, an admin may configure Squid to log
6141 which "user group" the transaction belongs to, where "user group"
6142 will be determined based on a set of ACLs and not [just]
6143 authentication information.
6144 Values of key/value pairs can be logged using %{key}note macros:
6146 note key value acl ...
6147 logformat myFormat ... %{key}note ...
6150 NAME: relaxed_header_parser
6151 COMMENT: on|off|warn
6153 LOC: Config.onoff.relaxed_header_parser
6156 In the default "on" setting Squid accepts certain forms
6157 of non-compliant HTTP messages where it is unambiguous
6158 what the sending application intended even if the message
6159 is not correctly formatted. The messages is then normalized
6160 to the correct form when forwarded by Squid.
6162 If set to "warn" then a warning will be emitted in cache.log
6163 each time such HTTP error is encountered.
6165 If set to "off" then such HTTP errors will cause the request
6166 or response to be rejected.
6169 NAME: collapsed_forwarding
6172 LOC: Config.onoff.collapsed_forwarding
6175 This option controls whether Squid is allowed to merge multiple
6176 potentially cachable requests for the same URI before Squid knows
6177 whether the response is going to be cachable.
6179 This feature is disabled by default: Enabling collapsed forwarding
6180 needlessly delays forwarding requests that look cachable (when they are
6181 collapsed) but then need to be forwarded individually anyway because
6182 they end up being for uncachable content. However, in some cases, such
6183 as accelleration of highly cachable content with periodic or groupped
6184 expiration times, the gains from collapsing [large volumes of
6185 simultenous refresh requests] outweigh losses from such delays.
6190 -----------------------------------------------------------------------------
6193 NAME: forward_timeout
6196 LOC: Config.Timeout.forward
6199 This parameter specifies how long Squid should at most attempt in
6200 finding a forwarding path for the request before giving up.
6203 NAME: connect_timeout
6206 LOC: Config.Timeout.connect
6209 This parameter specifies how long to wait for the TCP connect to
6210 the requested server or peer to complete before Squid should
6211 attempt to find another path where to forward the request.
6214 NAME: peer_connect_timeout
6217 LOC: Config.Timeout.peer_connect
6220 This parameter specifies how long to wait for a pending TCP
6221 connection to a peer cache. The default is 30 seconds. You
6222 may also set different timeout values for individual neighbors
6223 with the 'connect-timeout' option on a 'cache_peer' line.
6229 LOC: Config.Timeout.read
6232 Applied on peer server connections.
6234 After each successful read(), the timeout will be extended by this
6235 amount. If no data is read again after this amount of time,
6236 the request is aborted and logged with ERR_READ_TIMEOUT.
6238 The default is 15 minutes.
6244 LOC: Config.Timeout.write
6247 This timeout is tracked for all connections that have data
6248 available for writing and are waiting for the socket to become
6249 ready. After each successful write, the timeout is extended by
6250 the configured amount. If Squid has data to write but the
6251 connection is not ready for the configured duration, the
6252 transaction associated with the connection is terminated. The
6253 default is 15 minutes.
6256 NAME: request_timeout
6258 LOC: Config.Timeout.request
6261 How long to wait for complete HTTP request headers after initial
6262 connection establishment.
6265 NAME: request_start_timeout
6267 LOC: Config.Timeout.request_start_timeout
6270 How long to wait for the first request byte after initial
6271 connection establishment.
6274 NAME: client_idle_pconn_timeout persistent_request_timeout
6276 LOC: Config.Timeout.clientIdlePconn
6279 How long to wait for the next HTTP request on a persistent
6280 client connection after the previous request completes.
6283 NAME: ftp_client_idle_timeout
6285 LOC: Config.Timeout.ftpClientIdle
6288 How long to wait for an FTP request on a connection to Squid ftp_port.
6289 Many FTP clients do not deal with idle connection closures well,
6290 necessitating a longer default timeout than client_idle_pconn_timeout
6291 used for incoming HTTP requests.
6294 NAME: client_lifetime
6297 LOC: Config.Timeout.lifetime
6300 The maximum amount of time a client (browser) is allowed to
6301 remain connected to the cache process. This protects the Cache
6302 from having a lot of sockets (and hence file descriptors) tied up
6303 in a CLOSE_WAIT state from remote clients that go away without
6304 properly shutting down (either because of a network failure or
6305 because of a poor client implementation). The default is one
6308 NOTE: The default value is intended to be much larger than any
6309 client would ever need to be connected to your cache. You
6310 should probably change client_lifetime only as a last resort.
6311 If you seem to have many client connections tying up
6312 filedescriptors, we recommend first tuning the read_timeout,
6313 request_timeout, persistent_request_timeout and quick_abort values.
6316 NAME: pconn_lifetime
6319 LOC: Config.Timeout.pconnLifetime
6322 Desired maximum lifetime of a persistent connection.
6323 When set, Squid will close a now-idle persistent connection that
6324 exceeded configured lifetime instead of moving the connection into
6325 the idle connection pool (or equivalent). No effect on ongoing/active
6326 transactions. Connection lifetime is the time period from the
6327 connection acceptance or opening time until "now".
6329 This limit is useful in environments with long-lived connections
6330 where Squid configuration or environmental factors change during a
6331 single connection lifetime. If unrestricted, some connections may
6332 last for hours and even days, ignoring those changes that should
6333 have affected their behavior or their existence.
6335 Currently, a new lifetime value supplied via Squid reconfiguration
6336 has no effect on already idle connections unless they become busy.
6338 When set to '0' this limit is not used.
6341 NAME: half_closed_clients
6343 LOC: Config.onoff.half_closed_clients
6346 Some clients may shutdown the sending side of their TCP
6347 connections, while leaving their receiving sides open. Sometimes,
6348 Squid can not tell the difference between a half-closed and a
6349 fully-closed TCP connection.
6351 By default, Squid will immediately close client connections when
6352 read(2) returns "no more data to read."
6354 Change this option to 'on' and Squid will keep open connections
6355 until a read(2) or write(2) on the socket returns an error.
6356 This may show some benefits for reverse proxies. But if not
6357 it is recommended to leave OFF.
6360 NAME: server_idle_pconn_timeout pconn_timeout
6362 LOC: Config.Timeout.serverIdlePconn
6365 Timeout for idle persistent connections to servers and other
6372 LOC: Ident::TheConfig.timeout
6375 Maximum time to wait for IDENT lookups to complete.
6377 If this is too high, and you enabled IDENT lookups from untrusted
6378 users, you might be susceptible to denial-of-service by having
6379 many ident requests going at once.
6382 NAME: shutdown_lifetime
6385 LOC: Config.shutdownLifetime
6388 When SIGTERM or SIGHUP is received, the cache is put into
6389 "shutdown pending" mode until all active sockets are closed.
6390 This value is the lifetime to set for all open descriptors
6391 during shutdown mode. Any active clients after this many
6392 seconds will receive a 'timeout' message.
6396 ADMINISTRATIVE PARAMETERS
6397 -----------------------------------------------------------------------------
6403 LOC: Config.adminEmail
6405 Email-address of local cache manager who will receive
6406 mail if the cache dies. The default is "webmaster".
6412 LOC: Config.EmailFrom
6414 From: email-address for mail sent when the cache dies.
6415 The default is to use 'squid@unique_hostname'.
6417 See also: unique_hostname directive.
6423 LOC: Config.EmailProgram
6425 Email program used to send mail if the cache dies.
6426 The default is "mail". The specified program must comply
6427 with the standard Unix mail syntax:
6428 mail-program recipient < mailfile
6430 Optional command line options can be specified.
6433 NAME: cache_effective_user
6435 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
6436 LOC: Config.effectiveUser
6438 If you start Squid as root, it will change its effective/real
6439 UID/GID to the user specified below. The default is to change
6440 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
6441 see also; cache_effective_group
6444 NAME: cache_effective_group
6447 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
6448 LOC: Config.effectiveGroup
6450 Squid sets the GID to the effective user's default group ID
6451 (taken from the password file) and supplementary group list
6452 from the groups membership.
6454 If you want Squid to run with a specific GID regardless of
6455 the group memberships of the effective user then set this
6456 to the group (or GID) you want Squid to run as. When set
6457 all other group privileges of the effective user are ignored
6458 and only this GID is effective. If Squid is not started as
6459 root the user starting Squid MUST be member of the specified
6462 This option is not recommended by the Squid Team.
6463 Our preference is for administrators to configure a secure
6464 user account for squid with UID/GID matching system policies.
6467 NAME: httpd_suppress_version_string
6471 LOC: Config.onoff.httpd_suppress_version_string
6473 Suppress Squid version string info in HTTP headers and HTML error pages.
6476 NAME: visible_hostname
6478 LOC: Config.visibleHostname
6480 DEFAULT_DOC: Automatically detect the system host name
6482 If you want to present a special hostname in error messages, etc,
6483 define this. Otherwise, the return value of gethostname()
6484 will be used. If you have multiple caches in a cluster and
6485 get errors about IP-forwarding you must set them to have individual
6486 names with this setting.
6489 NAME: unique_hostname
6491 LOC: Config.uniqueHostname
6493 DEFAULT_DOC: Copy the value from visible_hostname
6495 If you want to have multiple machines with the same
6496 'visible_hostname' you must give each machine a different
6497 'unique_hostname' so forwarding loops can be detected.
6500 NAME: hostname_aliases
6502 LOC: Config.hostnameAliases
6505 A list of other DNS names your cache has.
6513 Minimum umask which should be enforced while the proxy
6514 is running, in addition to the umask set at startup.
6516 For a traditional octal representation of umasks, start
6521 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6522 -----------------------------------------------------------------------------
6524 This section contains parameters for the (optional) cache
6525 announcement service. This service is provided to help
6526 cache administrators locate one another in order to join or
6527 create cache hierarchies.
6529 An 'announcement' message is sent (via UDP) to the registration
6530 service by Squid. By default, the announcement message is NOT
6531 SENT unless you enable it with 'announce_period' below.
6533 The announcement message includes your hostname, plus the
6534 following information from this configuration file:
6540 All current information is processed regularly and made
6541 available on the Web at http://www.ircache.net/Cache/Tracker/.
6544 NAME: announce_period
6546 LOC: Config.Announce.period
6548 DEFAULT_DOC: Announcement messages disabled.
6550 This is how frequently to send cache announcements.
6552 To enable announcing your cache, just set an announce period.
6555 announce_period 1 day
6560 DEFAULT: tracker.ircache.net
6561 LOC: Config.Announce.host
6563 Set the hostname where announce registration messages will be sent.
6565 See also announce_port and announce_file
6571 LOC: Config.Announce.file
6573 The contents of this file will be included in the announce
6574 registration messages.
6580 LOC: Config.Announce.port
6582 Set the port where announce registration messages will be sent.
6584 See also announce_host and announce_file
6588 HTTPD-ACCELERATOR OPTIONS
6589 -----------------------------------------------------------------------------
6592 NAME: httpd_accel_surrogate_id
6595 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
6596 LOC: Config.Accel.surrogate_id
6598 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
6599 need an identification token to allow control targeting. Because
6600 a farm of surrogates may all perform the same tasks, they may share
6601 an identification token.
6604 NAME: http_accel_surrogate_remote
6608 LOC: Config.onoff.surrogate_is_remote
6610 Remote surrogates (such as those in a CDN) honour the header
6611 "Surrogate-Control: no-store-remote".
6613 Set this to on to have squid behave as a remote surrogate.
6617 IFDEF: USE_SQUID_ESI
6618 COMMENT: libxml2|expat|custom
6620 LOC: ESIParser::Type
6623 ESI markup is not strictly XML compatible. The custom ESI parser
6624 will give higher performance, but cannot handle non ASCII character
6629 DELAY POOL PARAMETERS
6630 -----------------------------------------------------------------------------
6634 TYPE: delay_pool_count
6636 IFDEF: USE_DELAY_POOLS
6639 This represents the number of delay pools to be used. For example,
6640 if you have one class 2 delay pool and one class 3 delays pool, you
6641 have a total of 2 delay pools.
6643 See also delay_parameters, delay_class, delay_access for pool
6644 configuration details.
6648 TYPE: delay_pool_class
6650 IFDEF: USE_DELAY_POOLS
6653 This defines the class of each delay pool. There must be exactly one
6654 delay_class line for each delay pool. For example, to define two
6655 delay pools, one of class 2 and one of class 3, the settings above
6659 delay_pools 4 # 4 delay pools
6660 delay_class 1 2 # pool 1 is a class 2 pool
6661 delay_class 2 3 # pool 2 is a class 3 pool
6662 delay_class 3 4 # pool 3 is a class 4 pool
6663 delay_class 4 5 # pool 4 is a class 5 pool
6665 The delay pool classes are:
6667 class 1 Everything is limited by a single aggregate
6670 class 2 Everything is limited by a single aggregate
6671 bucket as well as an "individual" bucket chosen
6672 from bits 25 through 32 of the IPv4 address.
6674 class 3 Everything is limited by a single aggregate
6675 bucket as well as a "network" bucket chosen
6676 from bits 17 through 24 of the IP address and a
6677 "individual" bucket chosen from bits 17 through
6678 32 of the IPv4 address.
6680 class 4 Everything in a class 3 delay pool, with an
6681 additional limit on a per user basis. This
6682 only takes effect if the username is established
6683 in advance - by forcing authentication in your
6686 class 5 Requests are grouped according their tag (see
6687 external_acl's tag= reply).
6690 Each pool also requires a delay_parameters directive to configure the pool size
6691 and speed limits used whenever the pool is applied to a request. Along with
6692 a set of delay_access directives to determine when it is used.
6694 NOTE: If an IP address is a.b.c.d
6695 -> bits 25 through 32 are "d"
6696 -> bits 17 through 24 are "c"
6697 -> bits 17 through 32 are "c * 256 + d"
6699 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6700 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6702 This clause only supports fast acl types.
6703 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6705 See also delay_parameters and delay_access.
6709 TYPE: delay_pool_access
6711 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6712 IFDEF: USE_DELAY_POOLS
6715 This is used to determine which delay pool a request falls into.
6717 delay_access is sorted per pool and the matching starts with pool 1,
6718 then pool 2, ..., and finally pool N. The first delay pool where the
6719 request is allowed is selected for the request. If it does not allow
6720 the request to any pool then the request is not delayed (default).
6722 For example, if you want some_big_clients in delay
6723 pool 1 and lotsa_little_clients in delay pool 2:
6725 delay_access 1 allow some_big_clients
6726 delay_access 1 deny all
6727 delay_access 2 allow lotsa_little_clients
6728 delay_access 2 deny all
6729 delay_access 3 allow authenticated_clients
6731 See also delay_parameters and delay_class.
6735 NAME: delay_parameters
6736 TYPE: delay_pool_rates
6738 IFDEF: USE_DELAY_POOLS
6741 This defines the parameters for a delay pool. Each delay pool has
6742 a number of "buckets" associated with it, as explained in the
6743 description of delay_class.
6745 For a class 1 delay pool, the syntax is:
6747 delay_parameters pool aggregate
6749 For a class 2 delay pool:
6751 delay_parameters pool aggregate individual
6753 For a class 3 delay pool:
6755 delay_parameters pool aggregate network individual
6757 For a class 4 delay pool:
6759 delay_parameters pool aggregate network individual user
6761 For a class 5 delay pool:
6763 delay_parameters pool tagrate
6765 The option variables are:
6767 pool a pool number - ie, a number between 1 and the
6768 number specified in delay_pools as used in
6771 aggregate the speed limit parameters for the aggregate bucket
6774 individual the speed limit parameters for the individual
6775 buckets (class 2, 3).
6777 network the speed limit parameters for the network buckets
6780 user the speed limit parameters for the user buckets
6783 tagrate the speed limit parameters for the tag buckets
6786 A pair of delay parameters is written restore/maximum, where restore is
6787 the number of bytes (not bits - modem and network speeds are usually
6788 quoted in bits) per second placed into the bucket, and maximum is the
6789 maximum number of bytes which can be in the bucket at any time.
6791 There must be one delay_parameters line for each delay pool.
6794 For example, if delay pool number 1 is a class 2 delay pool as in the
6795 above example, and is being used to strictly limit each host to 64Kbit/sec
6796 (plus overheads), with no overall limit, the line is:
6798 delay_parameters 1 none 8000/8000
6800 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
6802 Note that the word 'none' is used to represent no limit.
6805 And, if delay pool number 2 is a class 3 delay pool as in the above
6806 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6807 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6808 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6809 to permit a decent web page to be downloaded at a decent speed
6810 (if the network is not being limited due to overuse) but slow down
6811 large downloads more significantly:
6813 delay_parameters 2 32000/32000 8000/8000 600/8000
6815 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
6816 8 x 8000 KByte/sec -> 64Kbit/sec.
6817 8 x 600 Byte/sec -> 4800bit/sec.
6820 Finally, for a class 4 delay pool as in the example - each user will
6821 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6823 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6826 See also delay_class and delay_access.
6830 NAME: delay_initial_bucket_level
6831 COMMENT: (percent, 0-100)
6834 IFDEF: USE_DELAY_POOLS
6835 LOC: Config.Delay.initial
6837 The initial bucket percentage is used to determine how much is put
6838 in each bucket when squid starts, is reconfigured, or first notices
6839 a host accessing it (in class 2 and class 3, individual hosts and
6840 networks only have buckets associated with them once they have been
6845 CLIENT DELAY POOL PARAMETERS
6846 -----------------------------------------------------------------------------
6849 NAME: client_delay_pools
6850 TYPE: client_delay_pool_count
6852 IFDEF: USE_DELAY_POOLS
6853 LOC: Config.ClientDelay
6855 This option specifies the number of client delay pools used. It must
6856 preceed other client_delay_* options.
6859 client_delay_pools 2
6861 See also client_delay_parameters and client_delay_access.
6864 NAME: client_delay_initial_bucket_level
6865 COMMENT: (percent, 0-no_limit)
6868 IFDEF: USE_DELAY_POOLS
6869 LOC: Config.ClientDelay.initial
6871 This option determines the initial bucket size as a percentage of
6872 max_bucket_size from client_delay_parameters. Buckets are created
6873 at the time of the "first" connection from the matching IP. Idle
6874 buckets are periodically deleted up.
6876 You can specify more than 100 percent but note that such "oversized"
6877 buckets are not refilled until their size goes down to max_bucket_size
6878 from client_delay_parameters.
6881 client_delay_initial_bucket_level 50
6884 NAME: client_delay_parameters
6885 TYPE: client_delay_pool_rates
6887 IFDEF: USE_DELAY_POOLS
6888 LOC: Config.ClientDelay
6891 This option configures client-side bandwidth limits using the
6894 client_delay_parameters pool speed_limit max_bucket_size
6896 pool is an integer ID used for client_delay_access matching.
6898 speed_limit is bytes added to the bucket per second.
6900 max_bucket_size is the maximum size of a bucket, enforced after any
6901 speed_limit additions.
6903 Please see the delay_parameters option for more information and
6907 client_delay_parameters 1 1024 2048
6908 client_delay_parameters 2 51200 16384
6910 See also client_delay_access.
6914 NAME: client_delay_access
6915 TYPE: client_delay_pool_access
6917 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6918 IFDEF: USE_DELAY_POOLS
6919 LOC: Config.ClientDelay
6921 This option determines the client-side delay pool for the
6924 client_delay_access pool_ID allow|deny acl_name
6926 All client_delay_access options are checked in their pool ID
6927 order, starting with pool 1. The first checked pool with allowed
6928 request is selected for the request. If no ACL matches or there
6929 are no client_delay_access options, the request bandwidth is not
6932 The ACL-selected pool is then used to find the
6933 client_delay_parameters for the request. Client-side pools are
6934 not used to aggregate clients. Clients are always aggregated
6935 based on their source IP addresses (one bucket per source IP).
6937 This clause only supports fast acl types.
6938 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6939 Additionally, only the client TCP connection details are available.
6940 ACLs testing HTTP properties will not work.
6942 Please see delay_access for more examples.
6945 client_delay_access 1 allow low_rate_network
6946 client_delay_access 2 allow vips_network
6949 See also client_delay_parameters and client_delay_pools.
6953 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6954 -----------------------------------------------------------------------------
6959 LOC: Config.Wccp.router
6961 DEFAULT_DOC: WCCP disabled.
6964 Use this option to define your WCCP ``home'' router for
6967 wccp_router supports a single WCCP(v1) router
6969 wccp2_router supports multiple WCCPv2 routers
6971 only one of the two may be used at the same time and defines
6972 which version of WCCP to use.
6976 TYPE: IpAddress_list
6977 LOC: Config.Wccp2.router
6979 DEFAULT_DOC: WCCPv2 disabled.
6982 Use this option to define your WCCP ``home'' router for
6985 wccp_router supports a single WCCP(v1) router
6987 wccp2_router supports multiple WCCPv2 routers
6989 only one of the two may be used at the same time and defines
6990 which version of WCCP to use.
6995 LOC: Config.Wccp.version
6999 This directive is only relevant if you need to set up WCCP(v1)
7000 to some very old and end-of-life Cisco routers. In all other
7001 setups it must be left unset or at the default setting.
7002 It defines an internal version in the WCCP(v1) protocol,
7003 with version 4 being the officially documented protocol.
7005 According to some users, Cisco IOS 11.2 and earlier only
7006 support WCCP version 3. If you're using that or an earlier
7007 version of IOS, you may need to change this value to 3, otherwise
7008 do not specify this parameter.
7011 NAME: wccp2_rebuild_wait
7013 LOC: Config.Wccp2.rebuildwait
7017 If this is enabled Squid will wait for the cache dir rebuild to finish
7018 before sending the first wccp2 HereIAm packet
7021 NAME: wccp2_forwarding_method
7023 LOC: Config.Wccp2.forwarding_method
7027 WCCP2 allows the setting of forwarding methods between the
7028 router/switch and the cache. Valid values are as follows:
7030 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
7031 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
7033 Currently (as of IOS 12.4) cisco routers only support GRE.
7034 Cisco switches only support the L2 redirect assignment method.
7037 NAME: wccp2_return_method
7039 LOC: Config.Wccp2.return_method
7043 WCCP2 allows the setting of return methods between the
7044 router/switch and the cache for packets that the cache
7045 decides not to handle. Valid values are as follows:
7047 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
7048 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
7050 Currently (as of IOS 12.4) cisco routers only support GRE.
7051 Cisco switches only support the L2 redirect assignment.
7053 If the "ip wccp redirect exclude in" command has been
7054 enabled on the cache interface, then it is still safe for
7055 the proxy server to use a l2 redirect method even if this
7056 option is set to GRE.
7059 NAME: wccp2_assignment_method
7061 LOC: Config.Wccp2.assignment_method
7065 WCCP2 allows the setting of methods to assign the WCCP hash
7066 Valid values are as follows:
7068 hash - Hash assignment
7069 mask - Mask assignment
7071 As a general rule, cisco routers support the hash assignment method
7072 and cisco switches support the mask assignment method.
7077 LOC: Config.Wccp2.info
7078 DEFAULT_IF_NONE: standard 0
7079 DEFAULT_DOC: Use the 'web-cache' standard service.
7082 WCCP2 allows for multiple traffic services. There are two
7083 types: "standard" and "dynamic". The standard type defines
7084 one service id - http (id 0). The dynamic service ids can be from
7085 51 to 255 inclusive. In order to use a dynamic service id
7086 one must define the type of traffic to be redirected; this is done
7087 using the wccp2_service_info option.
7089 The "standard" type does not require a wccp2_service_info option,
7090 just specifying the service id will suffice.
7092 MD5 service authentication can be enabled by adding
7093 "password=<password>" to the end of this service declaration.
7097 wccp2_service standard 0 # for the 'web-cache' standard service
7098 wccp2_service dynamic 80 # a dynamic service type which will be
7099 # fleshed out with subsequent options.
7100 wccp2_service standard 0 password=foo
7103 NAME: wccp2_service_info
7104 TYPE: wccp2_service_info
7105 LOC: Config.Wccp2.info
7109 Dynamic WCCPv2 services require further information to define the
7110 traffic you wish to have diverted.
7114 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
7115 priority=<priority> ports=<port>,<port>..
7117 The relevant WCCPv2 flags:
7118 + src_ip_hash, dst_ip_hash
7119 + source_port_hash, dst_port_hash
7120 + src_ip_alt_hash, dst_ip_alt_hash
7121 + src_port_alt_hash, dst_port_alt_hash
7124 The port list can be one to eight entries.
7128 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
7129 priority=240 ports=80
7131 Note: the service id must have been defined by a previous
7132 'wccp2_service dynamic <id>' entry.
7137 LOC: Config.Wccp2.weight
7141 Each cache server gets assigned a set of the destination
7142 hash proportional to their weight.
7147 LOC: Config.Wccp.address
7149 DEFAULT_DOC: Address selected by the operating system.
7152 Use this option if you require WCCPv2 to use a specific
7155 The default behavior is to not bind to any specific address.
7160 LOC: Config.Wccp2.address
7162 DEFAULT_DOC: Address selected by the operating system.
7165 Use this option if you require WCCP to use a specific
7168 The default behavior is to not bind to any specific address.
7172 PERSISTENT CONNECTION HANDLING
7173 -----------------------------------------------------------------------------
7175 Also see "pconn_timeout" in the TIMEOUTS section
7178 NAME: client_persistent_connections
7180 LOC: Config.onoff.client_pconns
7183 Persistent connection support for clients.
7184 Squid uses persistent connections (when allowed). You can use
7185 this option to disable persistent connections with clients.
7188 NAME: server_persistent_connections
7190 LOC: Config.onoff.server_pconns
7193 Persistent connection support for servers.
7194 Squid uses persistent connections (when allowed). You can use
7195 this option to disable persistent connections with servers.
7198 NAME: persistent_connection_after_error
7200 LOC: Config.onoff.error_pconns
7203 With this directive the use of persistent connections after
7204 HTTP errors can be disabled. Useful if you have clients
7205 who fail to handle errors on persistent connections proper.
7208 NAME: detect_broken_pconn
7210 LOC: Config.onoff.detect_broken_server_pconns
7213 Some servers have been found to incorrectly signal the use
7214 of HTTP/1.0 persistent connections even on replies not
7215 compatible, causing significant delays. This server problem
7216 has mostly been seen on redirects.
7218 By enabling this directive Squid attempts to detect such
7219 broken replies and automatically assume the reply is finished
7220 after 10 seconds timeout.
7224 CACHE DIGEST OPTIONS
7225 -----------------------------------------------------------------------------
7228 NAME: digest_generation
7229 IFDEF: USE_CACHE_DIGESTS
7231 LOC: Config.onoff.digest_generation
7234 This controls whether the server will generate a Cache Digest
7235 of its contents. By default, Cache Digest generation is
7236 enabled if Squid is compiled with --enable-cache-digests defined.
7239 NAME: digest_bits_per_entry
7240 IFDEF: USE_CACHE_DIGESTS
7242 LOC: Config.digest.bits_per_entry
7245 This is the number of bits of the server's Cache Digest which
7246 will be associated with the Digest entry for a given HTTP
7247 Method and URL (public key) combination. The default is 5.
7250 NAME: digest_rebuild_period
7251 IFDEF: USE_CACHE_DIGESTS
7254 LOC: Config.digest.rebuild_period
7257 This is the wait time between Cache Digest rebuilds.
7260 NAME: digest_rewrite_period
7262 IFDEF: USE_CACHE_DIGESTS
7264 LOC: Config.digest.rewrite_period
7267 This is the wait time between Cache Digest writes to
7271 NAME: digest_swapout_chunk_size
7274 IFDEF: USE_CACHE_DIGESTS
7275 LOC: Config.digest.swapout_chunk_size
7278 This is the number of bytes of the Cache Digest to write to
7279 disk at a time. It defaults to 4096 bytes (4KB), the Squid
7283 NAME: digest_rebuild_chunk_percentage
7284 COMMENT: (percent, 0-100)
7285 IFDEF: USE_CACHE_DIGESTS
7287 LOC: Config.digest.rebuild_chunk_percentage
7290 This is the percentage of the Cache Digest to be scanned at a
7291 time. By default it is set to 10% of the Cache Digest.
7296 -----------------------------------------------------------------------------
7301 LOC: Config.Port.snmp
7303 DEFAULT_DOC: SNMP disabled.
7306 The port number where Squid listens for SNMP requests. To enable
7307 SNMP support set this to a suitable port number. Port number
7308 3401 is often used for the Squid SNMP agent. By default it's
7309 set to "0" (disabled)
7317 LOC: Config.accessList.snmp
7319 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
7322 Allowing or denying access to the SNMP port.
7324 All access to the agent is denied by default.
7327 snmp_access allow|deny [!]aclname ...
7329 This clause only supports fast acl types.
7330 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7333 snmp_access allow snmppublic localhost
7334 snmp_access deny all
7337 NAME: snmp_incoming_address
7339 LOC: Config.Addrs.snmp_incoming
7341 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
7344 Just like 'udp_incoming_address', but for the SNMP port.
7346 snmp_incoming_address is used for the SNMP socket receiving
7347 messages from SNMP agents.
7349 The default snmp_incoming_address is to listen on all
7350 available network interfaces.
7353 NAME: snmp_outgoing_address
7355 LOC: Config.Addrs.snmp_outgoing
7357 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
7360 Just like 'udp_outgoing_address', but for the SNMP port.
7362 snmp_outgoing_address is used for SNMP packets returned to SNMP
7365 If snmp_outgoing_address is not set it will use the same socket
7366 as snmp_incoming_address. Only change this if you want to have
7367 SNMP replies sent using another address than where this Squid
7368 listens for SNMP queries.
7370 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
7371 the same value since they both use the same port.
7376 -----------------------------------------------------------------------------
7379 NAME: icp_port udp_port
7382 DEFAULT_DOC: ICP disabled.
7383 LOC: Config.Port.icp
7385 The port number where Squid sends and receives ICP queries to
7386 and from neighbor caches. The standard UDP port for ICP is 3130.
7389 icp_port @DEFAULT_ICP_PORT@
7396 DEFAULT_DOC: HTCP disabled.
7397 LOC: Config.Port.htcp
7399 The port number where Squid sends and receives HTCP queries to
7400 and from neighbor caches. To turn it on you want to set it to
7407 NAME: log_icp_queries
7411 LOC: Config.onoff.log_udp
7413 If set, ICP queries are logged to access.log. You may wish
7414 do disable this if your ICP load is VERY high to speed things
7415 up or to simplify log analysis.
7418 NAME: udp_incoming_address
7420 LOC:Config.Addrs.udp_incoming
7422 DEFAULT_DOC: Accept packets from all machine interfaces.
7424 udp_incoming_address is used for UDP packets received from other
7427 The default behavior is to not bind to any specific address.
7429 Only change this if you want to have all UDP queries received on
7430 a specific interface/address.
7432 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
7433 modules. Altering it will affect all of them in the same manner.
7435 see also; udp_outgoing_address
7437 NOTE, udp_incoming_address and udp_outgoing_address can not
7438 have the same value since they both use the same port.
7441 NAME: udp_outgoing_address
7443 LOC: Config.Addrs.udp_outgoing
7445 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
7447 udp_outgoing_address is used for UDP packets sent out to other
7450 The default behavior is to not bind to any specific address.
7452 Instead it will use the same socket as udp_incoming_address.
7453 Only change this if you want to have UDP queries sent using another
7454 address than where this Squid listens for UDP queries from other
7457 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7458 modules. Altering it will affect all of them in the same manner.
7460 see also; udp_incoming_address
7462 NOTE, udp_incoming_address and udp_outgoing_address can not
7463 have the same value since they both use the same port.
7470 LOC: Config.onoff.icp_hit_stale
7472 If you want to return ICP_HIT for stale cache objects, set this
7473 option to 'on'. If you have sibling relationships with caches
7474 in other administrative domains, this should be 'off'. If you only
7475 have sibling relationships with caches under your control,
7476 it is probably okay to set this to 'on'.
7477 If set to 'on', your siblings should use the option "allow-miss"
7478 on their cache_peer lines for connecting to you.
7481 NAME: minimum_direct_hops
7484 LOC: Config.minDirectHops
7486 If using the ICMP pinging stuff, do direct fetches for sites
7487 which are no more than this many hops away.
7490 NAME: minimum_direct_rtt
7494 LOC: Config.minDirectRtt
7496 If using the ICMP pinging stuff, do direct fetches for sites
7497 which are no more than this many rtt milliseconds away.
7503 LOC: Config.Netdb.low
7505 The low water mark for the ICMP measurement database.
7507 Note: high watermark controlled by netdb_high directive.
7509 These watermarks are counts, not percents. The defaults are
7510 (low) 900 and (high) 1000. When the high water mark is
7511 reached, database entries will be deleted until the low
7518 LOC: Config.Netdb.high
7520 The high water mark for the ICMP measurement database.
7522 Note: low watermark controlled by netdb_low directive.
7524 These watermarks are counts, not percents. The defaults are
7525 (low) 900 and (high) 1000. When the high water mark is
7526 reached, database entries will be deleted until the low
7530 NAME: netdb_ping_period
7532 LOC: Config.Netdb.period
7535 The minimum period for measuring a site. There will be at
7536 least this much delay between successive pings to the same
7537 network. The default is five minutes.
7544 LOC: Config.onoff.query_icmp
7546 If you want to ask your peers to include ICMP data in their ICP
7547 replies, enable this option.
7549 If your peer has configured Squid (during compilation) with
7550 '--enable-icmp' that peer will send ICMP pings to origin server
7551 sites of the URLs it receives. If you enable this option the
7552 ICP replies from that peer will include the ICMP data (if available).
7553 Then, when choosing a parent cache, Squid will choose the parent with
7554 the minimal RTT to the origin server. When this happens, the
7555 hierarchy field of the access.log will be
7556 "CLOSEST_PARENT_MISS". This option is off by default.
7559 NAME: test_reachability
7563 LOC: Config.onoff.test_reachability
7565 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
7566 instead of ICP_MISS if the target host is NOT in the ICMP
7567 database, or has a zero RTT.
7570 NAME: icp_query_timeout
7573 DEFAULT_DOC: Dynamic detection.
7575 LOC: Config.Timeout.icp_query
7577 Normally Squid will automatically determine an optimal ICP
7578 query timeout value based on the round-trip-time of recent ICP
7579 queries. If you want to override the value determined by
7580 Squid, set this 'icp_query_timeout' to a non-zero value. This
7581 value is specified in MILLISECONDS, so, to use a 2-second
7582 timeout (the old default), you would write:
7584 icp_query_timeout 2000
7587 NAME: maximum_icp_query_timeout
7591 LOC: Config.Timeout.icp_query_max
7593 Normally the ICP query timeout is determined dynamically. But
7594 sometimes it can lead to very large values (say 5 seconds).
7595 Use this option to put an upper limit on the dynamic timeout
7596 value. Do NOT use this option to always use a fixed (instead
7597 of a dynamic) timeout value. To set a fixed timeout see the
7598 'icp_query_timeout' directive.
7601 NAME: minimum_icp_query_timeout
7605 LOC: Config.Timeout.icp_query_min
7607 Normally the ICP query timeout is determined dynamically. But
7608 sometimes it can lead to very small timeouts, even lower than
7609 the normal latency variance on your link due to traffic.
7610 Use this option to put an lower limit on the dynamic timeout
7611 value. Do NOT use this option to always use a fixed (instead
7612 of a dynamic) timeout value. To set a fixed timeout see the
7613 'icp_query_timeout' directive.
7616 NAME: background_ping_rate
7620 LOC: Config.backgroundPingRate
7622 Controls how often the ICP pings are sent to siblings that
7623 have background-ping set.
7627 MULTICAST ICP OPTIONS
7628 -----------------------------------------------------------------------------
7633 LOC: Config.mcast_group_list
7636 This tag specifies a list of multicast groups which your server
7637 should join to receive multicasted ICP queries.
7639 NOTE! Be very careful what you put here! Be sure you
7640 understand the difference between an ICP _query_ and an ICP
7641 _reply_. This option is to be set only if you want to RECEIVE
7642 multicast queries. Do NOT set this option to SEND multicast
7643 ICP (use cache_peer for that). ICP replies are always sent via
7644 unicast, so this option does not affect whether or not you will
7645 receive replies from multicast group members.
7647 You must be very careful to NOT use a multicast address which
7648 is already in use by another group of caches.
7650 If you are unsure about multicast, please read the Multicast
7651 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7653 Usage: mcast_groups 239.128.16.128 224.0.1.20
7655 By default, Squid doesn't listen on any multicast groups.
7658 NAME: mcast_miss_addr
7659 IFDEF: MULTICAST_MISS_STREAM
7661 LOC: Config.mcast_miss.addr
7663 DEFAULT_DOC: disabled.
7665 If you enable this option, every "cache miss" URL will
7666 be sent out on the specified multicast address.
7668 Do not enable this option unless you are are absolutely
7669 certain you understand what you are doing.
7672 NAME: mcast_miss_ttl
7673 IFDEF: MULTICAST_MISS_STREAM
7675 LOC: Config.mcast_miss.ttl
7678 This is the time-to-live value for packets multicasted
7679 when multicasting off cache miss URLs is enabled. By
7680 default this is set to 'site scope', i.e. 16.
7683 NAME: mcast_miss_port
7684 IFDEF: MULTICAST_MISS_STREAM
7686 LOC: Config.mcast_miss.port
7689 This is the port number to be used in conjunction with
7693 NAME: mcast_miss_encode_key
7694 IFDEF: MULTICAST_MISS_STREAM
7696 LOC: Config.mcast_miss.encode_key
7697 DEFAULT: XXXXXXXXXXXXXXXX
7699 The URLs that are sent in the multicast miss stream are
7700 encrypted. This is the encryption key.
7703 NAME: mcast_icp_query_timeout
7707 LOC: Config.Timeout.mcast_icp_query
7709 For multicast peers, Squid regularly sends out ICP "probes" to
7710 count how many other peers are listening on the given multicast
7711 address. This value specifies how long Squid should wait to
7712 count all the replies. The default is 2000 msec, or 2
7717 INTERNAL ICON OPTIONS
7718 -----------------------------------------------------------------------------
7721 NAME: icon_directory
7723 LOC: Config.icons.directory
7724 DEFAULT: @DEFAULT_ICON_DIR@
7726 Where the icons are stored. These are normally kept in
7730 NAME: global_internal_static
7732 LOC: Config.onoff.global_internal_static
7735 This directive controls is Squid should intercept all requests for
7736 /squid-internal-static/ no matter which host the URL is requesting
7737 (default on setting), or if nothing special should be done for
7738 such URLs (off setting). The purpose of this directive is to make
7739 icons etc work better in complex cache hierarchies where it may
7740 not always be possible for all corners in the cache mesh to reach
7741 the server generating a directory listing.
7744 NAME: short_icon_urls
7746 LOC: Config.icons.use_short_names
7749 If this is enabled Squid will use short URLs for icons.
7750 If disabled it will revert to the old behavior of including
7751 it's own name and port in the URL.
7753 If you run a complex cache hierarchy with a mix of Squid and
7754 other proxies you may need to disable this directive.
7759 -----------------------------------------------------------------------------
7762 NAME: error_directory
7764 LOC: Config.errorDirectory
7766 DEFAULT_DOC: Send error pages in the clients preferred language
7768 If you wish to create your own versions of the default
7769 error files to customize them to suit your company copy
7770 the error/template files to another directory and point
7773 WARNING: This option will disable multi-language support
7774 on error pages if used.
7776 The squid developers are interested in making squid available in
7777 a wide variety of languages. If you are making translations for a
7778 language that Squid does not currently provide please consider
7779 contributing your translation back to the project.
7780 http://wiki.squid-cache.org/Translations
7782 The squid developers working on translations are happy to supply drop-in
7783 translated error files in exchange for any new language contributions.
7786 NAME: error_default_language
7787 IFDEF: USE_ERR_LOCALES
7789 LOC: Config.errorDefaultLanguage
7791 DEFAULT_DOC: Generate English language pages.
7793 Set the default language which squid will send error pages in
7794 if no existing translation matches the clients language
7797 If unset (default) generic English will be used.
7799 The squid developers are interested in making squid available in
7800 a wide variety of languages. If you are interested in making
7801 translations for any language see the squid wiki for details.
7802 http://wiki.squid-cache.org/Translations
7805 NAME: error_log_languages
7806 IFDEF: USE_ERR_LOCALES
7808 LOC: Config.errorLogMissingLanguages
7811 Log to cache.log what languages users are attempting to
7812 auto-negotiate for translations.
7814 Successful negotiations are not logged. Only failures
7815 have meaning to indicate that Squid may need an upgrade
7816 of its error page translations.
7819 NAME: err_page_stylesheet
7821 LOC: Config.errorStylesheet
7822 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7824 CSS Stylesheet to pattern the display of Squid default error pages.
7826 For information on CSS see http://www.w3.org/Style/CSS/
7831 LOC: Config.errHtmlText
7834 HTML text to include in error messages. Make this a "mailto"
7835 URL to your admin address, or maybe just a link to your
7836 organizations Web page.
7838 To include this in your error messages, you must rewrite
7839 the error template files (found in the "errors" directory).
7840 Wherever you want the 'err_html_text' line to appear,
7841 insert a %L tag in the error template file.
7844 NAME: email_err_data
7847 LOC: Config.onoff.emailErrData
7850 If enabled, information about the occurred error will be
7851 included in the mailto links of the ERR pages (if %W is set)
7852 so that the email body contains the data.
7853 Syntax is <A HREF="mailto:%w%W">%w</A>
7858 LOC: Config.denyInfoList
7861 Usage: deny_info err_page_name acl
7862 or deny_info http://... acl
7863 or deny_info TCP_RESET acl
7865 This can be used to return a ERR_ page for requests which
7866 do not pass the 'http_access' rules. Squid remembers the last
7867 acl it evaluated in http_access, and if a 'deny_info' line exists
7868 for that ACL Squid returns a corresponding error page.
7870 The acl is typically the last acl on the http_access deny line which
7871 denied access. The exceptions to this rule are:
7872 - When Squid needs to request authentication credentials. It's then
7873 the first authentication related acl encountered
7874 - When none of the http_access lines matches. It's then the last
7875 acl processed on the last http_access line.
7876 - When the decision to deny access was made by an adaptation service,
7877 the acl name is the corresponding eCAP or ICAP service_name.
7879 NP: If providing your own custom error pages with error_directory
7880 you may also specify them by your custom file name:
7881 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7883 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7884 may be specified by prefixing the file name with the code and a colon.
7885 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7887 Alternatively you can tell Squid to reset the TCP connection
7888 by specifying TCP_RESET.
7890 Or you can specify an error URL or URL pattern. The browsers will
7891 get redirected to the specified URL after formatting tags have
7892 been replaced. Redirect will be done with 302 or 307 according to
7893 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7894 the URL. e.g. 303:http://example.com/
7897 %a - username (if available. Password NOT included)
7900 %E - Error description
7902 %H - Request domain name
7903 %i - Client IP Address
7905 %o - Message result from external ACL helper
7906 %p - Request Port number
7907 %P - Request Protocol name
7908 %R - Request URL path
7909 %T - Timestamp in RFC 1123 format
7910 %U - Full canonical URL from client
7911 (HTTPS URLs terminate with *)
7912 %u - Full canonical URL from client
7913 %w - Admin email from squid.conf
7915 %% - Literal percent (%) code
7920 OPTIONS INFLUENCING REQUEST FORWARDING
7921 -----------------------------------------------------------------------------
7924 NAME: nonhierarchical_direct
7926 LOC: Config.onoff.nonhierarchical_direct
7929 By default, Squid will send any non-hierarchical requests
7930 (not cacheable request type) direct to origin servers.
7932 When this is set to "off", Squid will prefer to send these
7933 requests to parents.
7935 Note that in most configurations, by turning this off you will only
7936 add latency to these request without any improvement in global hit
7939 This option only sets a preference. If the parent is unavailable a
7940 direct connection to the origin server may still be attempted. To
7941 completely prevent direct connections use never_direct.
7946 LOC: Config.onoff.prefer_direct
7949 Normally Squid tries to use parents for most requests. If you for some
7950 reason like it to first try going direct and only use a parent if
7951 going direct fails set this to on.
7953 By combining nonhierarchical_direct off and prefer_direct on you
7954 can set up Squid to use a parent as a backup path if going direct
7957 Note: If you want Squid to use parents for all requests see
7958 the never_direct directive. prefer_direct only modifies how Squid
7959 acts on cacheable requests.
7962 NAME: cache_miss_revalidate
7966 LOC: Config.onoff.cache_miss_revalidate
7968 RFC 7232 defines a conditional request mechanism to prevent
7969 response objects being unnecessarily transferred over the network.
7970 If that mechanism is used by the client and a cache MISS occurs
7971 it can prevent new cache entries being created.
7973 This option determines whether Squid on cache MISS will pass the
7974 client revalidation request to the server or tries to fetch new
7975 content for caching. It can be useful while the cache is mostly
7976 empty to more quickly have the cache populated by generating
7977 non-conditional GETs.
7979 When set to 'on' (default), Squid will pass all client If-* headers
7980 to the server. This permits server responses without a cacheable
7981 payload to be delivered and on MISS no new cache entry is created.
7983 When set to 'off' and if the request is cacheable, Squid will
7984 remove the clients If-Modified-Since and If-None-Match headers from
7985 the request sent to the server. This requests a 200 status response
7986 from the server to create a new cache entry with.
7991 LOC: Config.accessList.AlwaysDirect
7993 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7995 Usage: always_direct allow|deny [!]aclname ...
7997 Here you can use ACL elements to specify requests which should
7998 ALWAYS be forwarded by Squid to the origin servers without using
7999 any peers. For example, to always directly forward requests for
8000 local servers ignoring any parents or siblings you may have use
8003 acl local-servers dstdomain my.domain.net
8004 always_direct allow local-servers
8006 To always forward FTP requests directly, use
8009 always_direct allow FTP
8011 NOTE: There is a similar, but opposite option named
8012 'never_direct'. You need to be aware that "always_direct deny
8013 foo" is NOT the same thing as "never_direct allow foo". You
8014 may need to use a deny rule to exclude a more-specific case of
8015 some other rule. Example:
8017 acl local-external dstdomain external.foo.net
8018 acl local-servers dstdomain .foo.net
8019 always_direct deny local-external
8020 always_direct allow local-servers
8022 NOTE: If your goal is to make the client forward the request
8023 directly to the origin server bypassing Squid then this needs
8024 to be done in the client configuration. Squid configuration
8025 can only tell Squid how Squid should fetch the object.
8027 NOTE: This directive is not related to caching. The replies
8028 is cached as usual even if you use always_direct. To not cache
8029 the replies see the 'cache' directive.
8031 This clause supports both fast and slow acl types.
8032 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
8037 LOC: Config.accessList.NeverDirect
8039 DEFAULT_DOC: Allow DNS results to be used for this request.
8041 Usage: never_direct allow|deny [!]aclname ...
8043 never_direct is the opposite of always_direct. Please read
8044 the description for always_direct if you have not already.
8046 With 'never_direct' you can use ACL elements to specify
8047 requests which should NEVER be forwarded directly to origin
8048 servers. For example, to force the use of a proxy for all
8049 requests, except those in your local domain use something like:
8051 acl local-servers dstdomain .foo.net
8052 never_direct deny local-servers
8053 never_direct allow all
8055 or if Squid is inside a firewall and there are local intranet
8056 servers inside the firewall use something like:
8058 acl local-intranet dstdomain .foo.net
8059 acl local-external dstdomain external.foo.net
8060 always_direct deny local-external
8061 always_direct allow local-intranet
8062 never_direct allow all
8064 This clause supports both fast and slow acl types.
8065 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
8069 ADVANCED NETWORKING OPTIONS
8070 -----------------------------------------------------------------------------
8073 NAME: incoming_udp_average incoming_icp_average
8076 LOC: Config.comm_incoming.udp.average
8078 Heavy voodoo here. I can't even believe you are reading this.
8079 Are you crazy? Don't even think about adjusting these unless
8080 you understand the algorithms in comm_select.c first!
8083 NAME: incoming_tcp_average incoming_http_average
8086 LOC: Config.comm_incoming.tcp.average
8088 Heavy voodoo here. I can't even believe you are reading this.
8089 Are you crazy? Don't even think about adjusting these unless
8090 you understand the algorithms in comm_select.c first!
8093 NAME: incoming_dns_average
8096 LOC: Config.comm_incoming.dns.average
8098 Heavy voodoo here. I can't even believe you are reading this.
8099 Are you crazy? Don't even think about adjusting these unless
8100 you understand the algorithms in comm_select.c first!
8103 NAME: min_udp_poll_cnt min_icp_poll_cnt
8106 LOC: Config.comm_incoming.udp.min_poll
8108 Heavy voodoo here. I can't even believe you are reading this.
8109 Are you crazy? Don't even think about adjusting these unless
8110 you understand the algorithms in comm_select.c first!
8113 NAME: min_dns_poll_cnt
8116 LOC: Config.comm_incoming.dns.min_poll
8118 Heavy voodoo here. I can't even believe you are reading this.
8119 Are you crazy? Don't even think about adjusting these unless
8120 you understand the algorithms in comm_select.c first!
8123 NAME: min_tcp_poll_cnt min_http_poll_cnt
8126 LOC: Config.comm_incoming.tcp.min_poll
8128 Heavy voodoo here. I can't even believe you are reading this.
8129 Are you crazy? Don't even think about adjusting these unless
8130 you understand the algorithms in comm_select.c first!
8136 LOC: Config.accept_filter
8140 The name of an accept(2) filter to install on Squid's
8141 listen socket(s). This feature is perhaps specific to
8142 FreeBSD and requires support in the kernel.
8144 The 'httpready' filter delays delivering new connections
8145 to Squid until a full HTTP request has been received.
8146 See the accf_http(9) man page for details.
8148 The 'dataready' filter delays delivering new connections
8149 to Squid until there is some data to process.
8150 See the accf_dataready(9) man page for details.
8154 The 'data' filter delays delivering of new connections
8155 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
8156 You may optionally specify a number of seconds to wait by
8157 'data=N' where N is the number of seconds. Defaults to 30
8158 if not specified. See the tcp(7) man page for details.
8161 accept_filter httpready
8166 NAME: client_ip_max_connections
8168 LOC: Config.client_ip_max_connections
8170 DEFAULT_DOC: No limit.
8172 Set an absolute limit on the number of connections a single
8173 client IP can use. Any more than this and Squid will begin to drop
8174 new connections from the client until it closes some links.
8176 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
8177 connections from the client. For finer control use the ACL access controls.
8179 Requires client_db to be enabled (the default).
8181 WARNING: This may noticably slow down traffic received via external proxies
8182 or NAT devices and cause them to rebound error messages back to their clients.
8185 NAME: tcp_recv_bufsize
8189 DEFAULT_DOC: Use operating system TCP defaults.
8190 LOC: Config.tcpRcvBufsz
8192 Size of receive buffer to set for TCP sockets. Probably just
8193 as easy to change your kernel's default.
8194 Omit from squid.conf to use the default buffer size.
8199 -----------------------------------------------------------------------------
8206 LOC: Adaptation::Icap::TheConfig.onoff
8209 If you want to enable the ICAP module support, set this to on.
8212 NAME: icap_connect_timeout
8215 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
8218 This parameter specifies how long to wait for the TCP connect to
8219 the requested ICAP server to complete before giving up and either
8220 terminating the HTTP transaction or bypassing the failure.
8222 The default for optional services is peer_connect_timeout.
8223 The default for essential services is connect_timeout.
8224 If this option is explicitly set, its value applies to all services.
8227 NAME: icap_io_timeout
8231 DEFAULT_DOC: Use read_timeout.
8232 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
8235 This parameter specifies how long to wait for an I/O activity on
8236 an established, active ICAP connection before giving up and
8237 either terminating the HTTP transaction or bypassing the
8241 NAME: icap_service_failure_limit
8242 COMMENT: limit [in memory-depth time-units]
8243 TYPE: icap_service_failure_limit
8245 LOC: Adaptation::Icap::TheConfig
8248 The limit specifies the number of failures that Squid tolerates
8249 when establishing a new TCP connection with an ICAP service. If
8250 the number of failures exceeds the limit, the ICAP service is
8251 not used for new ICAP requests until it is time to refresh its
8254 A negative value disables the limit. Without the limit, an ICAP
8255 service will not be considered down due to connectivity failures
8256 between ICAP OPTIONS requests.
8258 Squid forgets ICAP service failures older than the specified
8259 value of memory-depth. The memory fading algorithm
8260 is approximate because Squid does not remember individual
8261 errors but groups them instead, splitting the option
8262 value into ten time slots of equal length.
8264 When memory-depth is 0 and by default this option has no
8265 effect on service failure expiration.
8267 Squid always forgets failures when updating service settings
8268 using an ICAP OPTIONS transaction, regardless of this option
8272 # suspend service usage after 10 failures in 5 seconds:
8273 icap_service_failure_limit 10 in 5 seconds
8276 NAME: icap_service_revival_delay
8279 LOC: Adaptation::Icap::TheConfig.service_revival_delay
8282 The delay specifies the number of seconds to wait after an ICAP
8283 OPTIONS request failure before requesting the options again. The
8284 failed ICAP service is considered "down" until fresh OPTIONS are
8287 The actual delay cannot be smaller than the hardcoded minimum
8288 delay of 30 seconds.
8291 NAME: icap_preview_enable
8295 LOC: Adaptation::Icap::TheConfig.preview_enable
8298 The ICAP Preview feature allows the ICAP server to handle the
8299 HTTP message by looking only at the beginning of the message body
8300 or even without receiving the body at all. In some environments,
8301 previews greatly speedup ICAP processing.
8303 During an ICAP OPTIONS transaction, the server may tell Squid what
8304 HTTP messages should be previewed and how big the preview should be.
8305 Squid will not use Preview if the server did not request one.
8307 To disable ICAP Preview for all ICAP services, regardless of
8308 individual ICAP server OPTIONS responses, set this option to "off".
8310 icap_preview_enable off
8313 NAME: icap_preview_size
8316 LOC: Adaptation::Icap::TheConfig.preview_size
8318 DEFAULT_DOC: No preview sent.
8320 The default size of preview data to be sent to the ICAP server.
8321 This value might be overwritten on a per server basis by OPTIONS requests.
8324 NAME: icap_206_enable
8328 LOC: Adaptation::Icap::TheConfig.allow206_enable
8331 206 (Partial Content) responses is an ICAP extension that allows the
8332 ICAP agents to optionally combine adapted and original HTTP message
8333 content. The decision to combine is postponed until the end of the
8334 ICAP response. Squid supports Partial Content extension by default.
8336 Activation of the Partial Content extension is negotiated with each
8337 ICAP service during OPTIONS exchange. Most ICAP servers should handle
8338 negotation correctly even if they do not support the extension, but
8339 some might fail. To disable Partial Content support for all ICAP
8340 services and to avoid any negotiation, set this option to "off".
8346 NAME: icap_default_options_ttl
8349 LOC: Adaptation::Icap::TheConfig.default_options_ttl
8352 The default TTL value for ICAP OPTIONS responses that don't have
8353 an Options-TTL header.
8356 NAME: icap_persistent_connections
8360 LOC: Adaptation::Icap::TheConfig.reuse_connections
8363 Whether or not Squid should use persistent connections to
8367 NAME: adaptation_send_client_ip icap_send_client_ip
8369 IFDEF: USE_ADAPTATION
8371 LOC: Adaptation::Config::send_client_ip
8374 If enabled, Squid shares HTTP client IP information with adaptation
8375 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
8376 For eCAP, Squid sets the libecap::metaClientIp transaction option.
8378 See also: adaptation_uses_indirect_client
8381 NAME: adaptation_send_username icap_send_client_username
8383 IFDEF: USE_ADAPTATION
8385 LOC: Adaptation::Config::send_username
8388 This sends authenticated HTTP client username (if available) to
8389 the adaptation service.
8391 For ICAP, the username value is encoded based on the
8392 icap_client_username_encode option and is sent using the header
8393 specified by the icap_client_username_header option.
8396 NAME: icap_client_username_header
8399 LOC: Adaptation::Icap::TheConfig.client_username_header
8400 DEFAULT: X-Client-Username
8402 ICAP request header name to use for adaptation_send_username.
8405 NAME: icap_client_username_encode
8409 LOC: Adaptation::Icap::TheConfig.client_username_encode
8412 Whether to base64 encode the authenticated client username.
8416 TYPE: icap_service_type
8418 LOC: Adaptation::Icap::TheConfig
8421 Defines a single ICAP service using the following format:
8423 icap_service id vectoring_point uri [option ...]
8426 an opaque identifier or name which is used to direct traffic to
8427 this specific service. Must be unique among all adaptation
8428 services in squid.conf.
8430 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8431 This specifies at which point of transaction processing the
8432 ICAP service should be activated. *_postcache vectoring points
8433 are not yet supported.
8435 uri: icap://servername:port/servicepath
8436 ICAP server and service location.
8437 icaps://servername:port/servicepath
8438 The "icap:" URI scheme is used for traditional ICAP server and
8439 service location (default port is 1344, connections are not
8440 encrypted). The "icaps:" URI scheme is for Secure ICAP
8441 services that use SSL/TLS-encrypted ICAP connections (by
8442 default, on port 11344).
8444 ICAP does not allow a single service to handle both REQMOD and RESPMOD
8445 transactions. Squid does not enforce that requirement. You can specify
8446 services with the same service_url and different vectoring_points. You
8447 can even specify multiple identical services as long as their
8448 service_names differ.
8450 To activate a service, use the adaptation_access directive. To group
8451 services, use adaptation_service_chain and adaptation_service_set.
8453 Service options are separated by white space. ICAP services support
8454 the following name=value options:
8457 If set to 'on' or '1', the ICAP service is treated as
8458 optional. If the service cannot be reached or malfunctions,
8459 Squid will try to ignore any errors and process the message as
8460 if the service was not enabled. No all ICAP errors can be
8461 bypassed. If set to 0, the ICAP service is treated as
8462 essential and all ICAP errors will result in an error page
8463 returned to the HTTP client.
8465 Bypass is off by default: services are treated as essential.
8468 If set to 'on' or '1', the ICAP service is allowed to
8469 dynamically change the current message adaptation plan by
8470 returning a chain of services to be used next. The services
8471 are specified using the X-Next-Services ICAP response header
8472 value, formatted as a comma-separated list of service names.
8473 Each named service should be configured in squid.conf. Other
8474 services are ignored. An empty X-Next-Services value results
8475 in an empty plan which ends the current adaptation.
8477 Dynamic adaptation plan may cross or cover multiple supported
8478 vectoring points in their natural processing order.
8480 Routing is not allowed by default: the ICAP X-Next-Services
8481 response header is ignored.
8484 Only has effect on split-stack systems. The default on those systems
8485 is to use IPv4-only connections. When set to 'on' this option will
8486 make Squid use IPv6-only connections to contact this ICAP service.
8488 on-overload=block|bypass|wait|force
8489 If the service Max-Connections limit has been reached, do
8490 one of the following for each new ICAP transaction:
8491 * block: send an HTTP error response to the client
8492 * bypass: ignore the "over-connected" ICAP service
8493 * wait: wait (in a FIFO queue) for an ICAP connection slot
8494 * force: proceed, ignoring the Max-Connections limit
8496 In SMP mode with N workers, each worker assumes the service
8497 connection limit is Max-Connections/N, even though not all
8498 workers may use a given service.
8500 The default value is "bypass" if service is bypassable,
8501 otherwise it is set to "wait".
8505 Use the given number as the Max-Connections limit, regardless
8506 of the Max-Connections value given by the service, if any.
8508 ==== ICAPS / TLS OPTIONS ====
8510 These options are used for Secure ICAP (icaps://....) services only.
8512 tls-cert=/path/to/ssl/certificate
8513 A client SSL certificate to use when connecting to
8516 tls-key=/path/to/ssl/key
8517 The private TLS/SSL key corresponding to sslcert above.
8518 If 'tls-key' is not specified 'tls-cert' is assumed to
8519 reference a combined PEM format file containing both the
8520 certificate and the key.
8522 tls-cipher=... The list of valid TLS/SSL ciphers to use when connecting
8523 to this icap server.
8526 The minimum TLS protocol version to permit. To control
8527 SSLv3 use the ssloptions= parameter.
8528 Supported Values: 1.0 (default), 1.1, 1.2
8530 tls-options=... Specify various OpenSSL library options:
8532 NO_SSLv3 Disallow the use of SSLv3
8534 NO_TLSv1 Disallow the use of TLSv1.0
8535 NO_TLSv1_1 Disallow the use of TLSv1.1
8536 NO_TLSv1_2 Disallow the use of TLSv1.2
8539 Always create a new key when using
8540 temporary/ephemeral DH key exchanges
8542 ALL Enable various bug workarounds
8543 suggested as "harmless" by OpenSSL
8544 Be warned that this reduces SSL/TLS
8545 strength to some attacks.
8547 See the OpenSSL SSL_CTX_set_options documentation for a
8548 more complete list. Options relevant only to SSLv2 are
8551 tls-cafile= PEM file containing CA certificates to use when verifying
8552 the icap server certificate.
8553 Use to specify intermediate CA certificate(s) if not sent
8554 by the server. Or the full CA chain for the server when
8555 using the tls-no-default-ca flag.
8556 May be repeated to load multiple files.
8558 tls-capath=... A directory containing additional CA certificates to
8559 use when verifying the icap server certificate.
8560 Requires OpenSSL or LibreSSL.
8562 tls-crlfile=... A certificate revocation list file to use when
8563 verifying the icap server certificate.
8565 tls-flags=... Specify various flags modifying the Squid TLS implementation:
8568 Accept certificates even if they fail to
8571 Don't verify the icap server certificate
8572 matches the server name
8575 Do no use the system default Trusted CA.
8577 tls-domain= The icap server name as advertised in it's certificate.
8578 Used for verifying the correctness of the received icap
8579 server certificate. If not specified the icap server
8580 hostname extracted from ICAP URI will be used.
8582 Older icap_service format without optional named parameters is
8583 deprecated but supported for backward compatibility.
8586 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
8587 icap_service svcLogger reqmod_precache icaps://icap2.mydomain.net:11344/reqmod routing=on
8591 TYPE: icap_class_type
8596 This deprecated option was documented to define an ICAP service
8597 chain, even though it actually defined a set of similar, redundant
8598 services, and the chains were not supported.
8600 To define a set of redundant services, please use the
8601 adaptation_service_set directive. For service chains, use
8602 adaptation_service_chain.
8606 TYPE: icap_access_type
8611 This option is deprecated. Please use adaptation_access, which
8612 has the same ICAP functionality, but comes with better
8613 documentation, and eCAP support.
8618 -----------------------------------------------------------------------------
8625 LOC: Adaptation::Ecap::TheConfig.onoff
8628 Controls whether eCAP support is enabled.
8632 TYPE: ecap_service_type
8634 LOC: Adaptation::Ecap::TheConfig
8637 Defines a single eCAP service
8639 ecap_service id vectoring_point uri [option ...]
8642 an opaque identifier or name which is used to direct traffic to
8643 this specific service. Must be unique among all adaptation
8644 services in squid.conf.
8646 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8647 This specifies at which point of transaction processing the
8648 eCAP service should be activated. *_postcache vectoring points
8649 are not yet supported.
8651 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
8652 Squid uses the eCAP service URI to match this configuration
8653 line with one of the dynamically loaded services. Each loaded
8654 eCAP service must have a unique URI. Obtain the right URI from
8655 the service provider.
8657 To activate a service, use the adaptation_access directive. To group
8658 services, use adaptation_service_chain and adaptation_service_set.
8660 Service options are separated by white space. eCAP services support
8661 the following name=value options:
8664 If set to 'on' or '1', the eCAP service is treated as optional.
8665 If the service cannot be reached or malfunctions, Squid will try
8666 to ignore any errors and process the message as if the service
8667 was not enabled. No all eCAP errors can be bypassed.
8668 If set to 'off' or '0', the eCAP service is treated as essential
8669 and all eCAP errors will result in an error page returned to the
8672 Bypass is off by default: services are treated as essential.
8675 If set to 'on' or '1', the eCAP service is allowed to
8676 dynamically change the current message adaptation plan by
8677 returning a chain of services to be used next.
8679 Dynamic adaptation plan may cross or cover multiple supported
8680 vectoring points in their natural processing order.
8682 Routing is not allowed by default.
8684 Older ecap_service format without optional named parameters is
8685 deprecated but supported for backward compatibility.
8689 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
8690 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
8693 NAME: loadable_modules
8695 IFDEF: USE_LOADABLE_MODULES
8696 LOC: Config.loadable_module_names
8699 Instructs Squid to load the specified dynamic module(s) or activate
8700 preloaded module(s).
8702 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
8706 MESSAGE ADAPTATION OPTIONS
8707 -----------------------------------------------------------------------------
8710 NAME: adaptation_service_set
8711 TYPE: adaptation_service_set_type
8712 IFDEF: USE_ADAPTATION
8717 Configures an ordered set of similar, redundant services. This is
8718 useful when hot standby or backup adaptation servers are available.
8720 adaptation_service_set set_name service_name1 service_name2 ...
8722 The named services are used in the set declaration order. The first
8723 applicable adaptation service from the set is used first. The next
8724 applicable service is tried if and only if the transaction with the
8725 previous service fails and the message waiting to be adapted is still
8728 When adaptation starts, broken services are ignored as if they were
8729 not a part of the set. A broken service is a down optional service.
8731 The services in a set must be attached to the same vectoring point
8732 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8734 If all services in a set are optional then adaptation failures are
8735 bypassable. If all services in the set are essential, then a
8736 transaction failure with one service may still be retried using
8737 another service from the set, but when all services fail, the master
8738 transaction fails as well.
8740 A set may contain a mix of optional and essential services, but that
8741 is likely to lead to surprising results because broken services become
8742 ignored (see above), making previously bypassable failures fatal.
8743 Technically, it is the bypassability of the last failed service that
8746 See also: adaptation_access adaptation_service_chain
8749 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
8750 adaptation service_set svcLogger loggerLocal loggerRemote
8753 NAME: adaptation_service_chain
8754 TYPE: adaptation_service_chain_type
8755 IFDEF: USE_ADAPTATION
8760 Configures a list of complementary services that will be applied
8761 one-by-one, forming an adaptation chain or pipeline. This is useful
8762 when Squid must perform different adaptations on the same message.
8764 adaptation_service_chain chain_name service_name1 svc_name2 ...
8766 The named services are used in the chain declaration order. The first
8767 applicable adaptation service from the chain is used first. The next
8768 applicable service is applied to the successful adaptation results of
8769 the previous service in the chain.
8771 When adaptation starts, broken services are ignored as if they were
8772 not a part of the chain. A broken service is a down optional service.
8774 Request satisfaction terminates the adaptation chain because Squid
8775 does not currently allow declaration of RESPMOD services at the
8776 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8778 The services in a chain must be attached to the same vectoring point
8779 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8781 A chain may contain a mix of optional and essential services. If an
8782 essential adaptation fails (or the failure cannot be bypassed for
8783 other reasons), the master transaction fails. Otherwise, the failure
8784 is bypassed as if the failed adaptation service was not in the chain.
8786 See also: adaptation_access adaptation_service_set
8789 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8792 NAME: adaptation_access
8793 TYPE: adaptation_access_type
8794 IFDEF: USE_ADAPTATION
8797 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8799 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8801 adaptation_access service_name allow|deny [!]aclname...
8802 adaptation_access set_name allow|deny [!]aclname...
8804 At each supported vectoring point, the adaptation_access
8805 statements are processed in the order they appear in this
8806 configuration file. Statements pointing to the following services
8807 are ignored (i.e., skipped without checking their ACL):
8809 - services serving different vectoring points
8810 - "broken-but-bypassable" services
8811 - "up" services configured to ignore such transactions
8812 (e.g., based on the ICAP Transfer-Ignore header).
8814 When a set_name is used, all services in the set are checked
8815 using the same rules, to find the first applicable one. See
8816 adaptation_service_set for details.
8818 If an access list is checked and there is a match, the
8819 processing stops: For an "allow" rule, the corresponding
8820 adaptation service is used for the transaction. For a "deny"
8821 rule, no adaptation service is activated.
8823 It is currently not possible to apply more than one adaptation
8824 service at the same vectoring point to the same HTTP transaction.
8826 See also: icap_service and ecap_service
8829 adaptation_access service_1 allow all
8832 NAME: adaptation_service_iteration_limit
8834 IFDEF: USE_ADAPTATION
8835 LOC: Adaptation::Config::service_iteration_limit
8838 Limits the number of iterations allowed when applying adaptation
8839 services to a message. If your longest adaptation set or chain
8840 may have more than 16 services, increase the limit beyond its
8841 default value of 16. If detecting infinite iteration loops sooner
8842 is critical, make the iteration limit match the actual number
8843 of services in your longest adaptation set or chain.
8845 Infinite adaptation loops are most likely with routing services.
8847 See also: icap_service routing=1
8850 NAME: adaptation_masterx_shared_names
8852 IFDEF: USE_ADAPTATION
8853 LOC: Adaptation::Config::masterx_shared_name
8856 For each master transaction (i.e., the HTTP request and response
8857 sequence, including all related ICAP and eCAP exchanges), Squid
8858 maintains a table of metadata. The table entries are (name, value)
8859 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8860 with the master transaction.
8862 This option specifies the table entry names that Squid must accept
8863 from and forward to the adaptation transactions.
8865 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8866 shared table by returning an ICAP header field with a name
8867 specified in adaptation_masterx_shared_names.
8869 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8870 shared table by implementing the libecap::visitEachOption() API
8871 to provide an option with a name specified in
8872 adaptation_masterx_shared_names.
8874 Squid will store and forward the set entry to subsequent adaptation
8875 transactions within the same master transaction scope.
8877 Only one shared entry name is supported at this time.
8880 # share authentication information among ICAP services
8881 adaptation_masterx_shared_names X-Subscriber-ID
8884 NAME: adaptation_meta
8886 IFDEF: USE_ADAPTATION
8887 LOC: Adaptation::Config::metaHeaders
8890 This option allows Squid administrator to add custom ICAP request
8891 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8892 Use it to pass custom authentication tokens and other
8893 transaction-state related meta information to an ICAP/eCAP service.
8895 The addition of a meta header is ACL-driven:
8896 adaptation_meta name value [!]aclname ...
8898 Processing for a given header name stops after the first ACL list match.
8899 Thus, it is impossible to add two headers with the same name. If no ACL
8900 lists match for a given header name, no such header is added. For
8903 # do not debug transactions except for those that need debugging
8904 adaptation_meta X-Debug 1 needs_debugging
8906 # log all transactions except for those that must remain secret
8907 adaptation_meta X-Log 1 !keep_secret
8909 # mark transactions from users in the "G 1" group
8910 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8912 The "value" parameter may be a regular squid.conf token or a "double
8913 quoted string". Within the quoted string, use backslash (\) to escape
8914 any character, which is currently only useful for escaping backslashes
8915 and double quotes. For example,
8916 "this string has one backslash (\\) and two \"quotes\""
8918 Used adaptation_meta header values may be logged via %note
8919 logformat code. If multiple adaptation_meta headers with the same name
8920 are used during master transaction lifetime, the header values are
8921 logged in the order they were used and duplicate values are ignored
8922 (only the first repeated value will be logged).
8928 LOC: Adaptation::Icap::TheConfig.repeat
8929 DEFAULT_IF_NONE: deny all
8931 This ACL determines which retriable ICAP transactions are
8932 retried. Transactions that received a complete ICAP response
8933 and did not have to consume or produce HTTP bodies to receive
8934 that response are usually retriable.
8936 icap_retry allow|deny [!]aclname ...
8938 Squid automatically retries some ICAP I/O timeouts and errors
8939 due to persistent connection race conditions.
8941 See also: icap_retry_limit
8944 NAME: icap_retry_limit
8947 LOC: Adaptation::Icap::TheConfig.repeat_limit
8949 DEFAULT_DOC: No retries are allowed.
8951 Limits the number of retries allowed.
8953 Communication errors due to persistent connection race
8954 conditions are unavoidable, automatically retried, and do not
8955 count against this limit.
8957 See also: icap_retry
8963 -----------------------------------------------------------------------------
8966 NAME: check_hostnames
8969 LOC: Config.onoff.check_hostnames
8971 For security and stability reasons Squid can check
8972 hostnames for Internet standard RFC compliance. If you want
8973 Squid to perform these checks turn this directive on.
8976 NAME: allow_underscore
8979 LOC: Config.onoff.allow_underscore
8981 Underscore characters is not strictly allowed in Internet hostnames
8982 but nevertheless used by many sites. Set this to off if you want
8983 Squid to be strict about the standard.
8984 This check is performed only when check_hostnames is set to on.
8987 NAME: dns_retransmit_interval
8990 LOC: Config.Timeout.idns_retransmit
8992 Initial retransmit interval for DNS queries. The interval is
8993 doubled each time all configured DNS servers have been tried.
8999 LOC: Config.Timeout.idns_query
9001 DNS Query timeout. If no response is received to a DNS query
9002 within this time all DNS servers for the queried domain
9003 are assumed to be unavailable.
9006 NAME: dns_packet_max
9008 DEFAULT_DOC: EDNS disabled
9010 LOC: Config.dns.packet_max
9012 Maximum number of bytes packet size to advertise via EDNS.
9013 Set to "none" to disable EDNS large packet support.
9015 For legacy reasons DNS UDP replies will default to 512 bytes which
9016 is too small for many responses. EDNS provides a means for Squid to
9017 negotiate receiving larger responses back immediately without having
9018 to failover with repeat requests. Responses larger than this limit
9019 will retain the old behaviour of failover to TCP DNS.
9021 Squid has no real fixed limit internally, but allowing packet sizes
9022 over 1500 bytes requires network jumbogram support and is usually not
9025 WARNING: The RFC also indicates that some older resolvers will reply
9026 with failure of the whole request if the extension is added. Some
9027 resolvers have already been identified which will reply with mangled
9028 EDNS response on occasion. Usually in response to many-KB jumbogram
9029 sizes being advertised by Squid.
9030 Squid will currently treat these both as an unable-to-resolve domain
9031 even if it would be resolvable without EDNS.
9038 DEFAULT_DOC: Search for single-label domain names is disabled.
9039 LOC: Config.onoff.res_defnames
9041 Normally the RES_DEFNAMES resolver option is disabled
9042 (see res_init(3)). This prevents caches in a hierarchy
9043 from interpreting single-component hostnames locally. To allow
9044 Squid to handle single-component names, enable this option.
9047 NAME: dns_multicast_local
9051 DEFAULT_DOC: Search for .local and .arpa names is disabled.
9052 LOC: Config.onoff.dns_mdns
9054 When set to on, Squid sends multicast DNS lookups on the local
9055 network for domains ending in .local and .arpa.
9056 This enables local servers and devices to be contacted in an
9057 ad-hoc or zero-configuration network environment.
9060 NAME: dns_nameservers
9063 DEFAULT_DOC: Use operating system definitions
9064 LOC: Config.dns_nameservers
9066 Use this if you want to specify a list of DNS name servers
9067 (IP addresses) to use instead of those given in your
9068 /etc/resolv.conf file.
9070 On Windows platforms, if no value is specified here or in
9071 the /etc/resolv.conf file, the list of DNS name servers are
9072 taken from the Windows registry, both static and dynamic DHCP
9073 configurations are supported.
9075 Example: dns_nameservers 10.0.0.1 192.172.0.4
9080 DEFAULT: @DEFAULT_HOSTS@
9081 LOC: Config.etcHostsPath
9083 Location of the host-local IP name-address associations
9084 database. Most Operating Systems have such a file on different
9086 - Un*X & Linux: /etc/hosts
9087 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
9088 (%SystemRoot% value install default is c:\winnt)
9089 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
9090 (%SystemRoot% value install default is c:\windows)
9091 - Windows 9x/Me: %windir%\hosts
9092 (%windir% value is usually c:\windows)
9093 - Cygwin: /etc/hosts
9095 The file contains newline-separated definitions, in the
9096 form ip_address_in_dotted_form name [name ...] names are
9097 whitespace-separated. Lines beginning with an hash (#)
9098 character are comments.
9100 The file is checked at startup and upon configuration.
9101 If set to 'none', it won't be checked.
9102 If append_domain is used, that domain will be added to
9103 domain-local (i.e. not containing any dot character) host
9109 LOC: Config.appendDomain
9111 DEFAULT_DOC: Use operating system definitions
9113 Appends local domain name to hostnames without any dots in
9114 them. append_domain must begin with a period.
9116 Be warned there are now Internet names with no dots in
9117 them using only top-domain names, so setting this may
9118 cause some Internet sites to become unavailable.
9121 append_domain .yourdomain.com
9124 NAME: ignore_unknown_nameservers
9126 LOC: Config.onoff.ignore_unknown_nameservers
9129 By default Squid checks that DNS responses are received
9130 from the same IP addresses they are sent to. If they
9131 don't match, Squid ignores the response and writes a warning
9132 message to cache.log. You can allow responses from unknown
9133 nameservers by setting this option to 'off'.
9139 LOC: Config.dns.v4_first
9141 With the IPv6 Internet being as fast or faster than IPv4 Internet
9142 for most networks Squid prefers to contact websites over IPv6.
9144 This option reverses the order of preference to make Squid contact
9145 dual-stack websites over IPv4 first. Squid will still perform both
9146 IPv6 and IPv4 DNS lookups before connecting.
9149 This option will restrict the situations under which IPv6
9150 connectivity is used (and tested). Hiding network problems
9151 which would otherwise be detected and warned about.
9155 COMMENT: (number of entries)
9158 LOC: Config.ipcache.size
9160 Maximum number of DNS IP cache entries.
9167 LOC: Config.ipcache.low
9174 LOC: Config.ipcache.high
9176 The size, low-, and high-water marks for the IP cache.
9179 NAME: fqdncache_size
9180 COMMENT: (number of entries)
9183 LOC: Config.fqdncache.size
9185 Maximum number of FQDN cache entries.
9190 -----------------------------------------------------------------------------
9193 NAME: configuration_includes_quoted_values
9195 TYPE: configuration_includes_quoted_values
9197 LOC: ConfigParser::RecognizeQuotedValues
9199 If set, Squid will recognize each "quoted string" after a configuration
9200 directive as a single parameter. The quotes are stripped before the
9201 parameter value is interpreted or used.
9202 See "Values with spaces, quotes, and other special characters"
9203 section for more details.
9210 LOC: Config.onoff.mem_pools
9212 If set, Squid will keep pools of allocated (but unused) memory
9213 available for future use. If memory is a premium on your
9214 system and you believe your malloc library outperforms Squid
9215 routines, disable this.
9218 NAME: memory_pools_limit
9222 LOC: Config.MemPools.limit
9224 Used only with memory_pools on:
9225 memory_pools_limit 50 MB
9227 If set to a non-zero value, Squid will keep at most the specified
9228 limit of allocated (but unused) memory in memory pools. All free()
9229 requests that exceed this limit will be handled by your malloc
9230 library. Squid does not pre-allocate any memory, just safe-keeps
9231 objects that otherwise would be free()d. Thus, it is safe to set
9232 memory_pools_limit to a reasonably high value even if your
9233 configuration will use less memory.
9235 If set to none, Squid will keep all memory it can. That is, there
9236 will be no limit on the total amount of memory used for safe-keeping.
9238 To disable memory allocation optimization, do not set
9239 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
9241 An overhead for maintaining memory pools is not taken into account
9242 when the limit is checked. This overhead is close to four bytes per
9243 object kept. However, pools may actually _save_ memory because of
9244 reduced memory thrashing in your malloc library.
9248 COMMENT: on|off|transparent|truncate|delete
9251 LOC: opt_forwarded_for
9253 If set to "on", Squid will append your client's IP address
9254 in the HTTP requests it forwards. By default it looks like:
9256 X-Forwarded-For: 192.1.2.3
9258 If set to "off", it will appear as
9260 X-Forwarded-For: unknown
9262 If set to "transparent", Squid will not alter the
9263 X-Forwarded-For header in any way.
9265 If set to "delete", Squid will delete the entire
9266 X-Forwarded-For header.
9268 If set to "truncate", Squid will remove all existing
9269 X-Forwarded-For entries, and place the client IP as the sole entry.
9272 NAME: cachemgr_passwd
9273 TYPE: cachemgrpasswd
9275 DEFAULT_DOC: No password. Actions which require password are denied.
9276 LOC: Config.passwd_list
9278 Specify passwords for cachemgr operations.
9280 Usage: cachemgr_passwd password action action ...
9282 Some valid actions are (see cache manager menu for a full list):
9322 * Indicates actions which will not be performed without a
9323 valid password, others can be performed if not listed here.
9325 To disable an action, set the password to "disable".
9326 To allow performing an action without a password, set the
9329 Use the keyword "all" to set the same password for all actions.
9332 cachemgr_passwd secret shutdown
9333 cachemgr_passwd lesssssssecret info stats/objects
9334 cachemgr_passwd disable all
9341 LOC: Config.onoff.client_db
9343 If you want to disable collecting per-client statistics,
9344 turn off client_db here.
9347 NAME: refresh_all_ims
9351 LOC: Config.onoff.refresh_all_ims
9353 When you enable this option, squid will always check
9354 the origin server for an update when a client sends an
9355 If-Modified-Since request. Many browsers use IMS
9356 requests when the user requests a reload, and this
9357 ensures those clients receive the latest version.
9359 By default (off), squid may return a Not Modified response
9360 based on the age of the cached version.
9363 NAME: reload_into_ims
9364 IFDEF: USE_HTTP_VIOLATIONS
9368 LOC: Config.onoff.reload_into_ims
9370 When you enable this option, client no-cache or ``reload''
9371 requests will be changed to If-Modified-Since requests.
9372 Doing this VIOLATES the HTTP standard. Enabling this
9373 feature could make you liable for problems which it
9376 see also refresh_pattern for a more selective approach.
9379 NAME: connect_retries
9381 LOC: Config.connect_retries
9383 DEFAULT_DOC: Do not retry failed connections.
9385 This sets the maximum number of connection attempts made for each
9386 TCP connection. The connect_retries attempts must all still
9387 complete within the connection timeout period.
9389 The default is not to re-try if the first connection attempt fails.
9390 The (not recommended) maximum is 10 tries.
9392 A warning message will be generated if it is set to a too-high
9393 value and the configured value will be over-ridden.
9395 Note: These re-tries are in addition to forward_max_tries
9396 which limit how many different addresses may be tried to find
9400 NAME: retry_on_error
9402 LOC: Config.retry.onerror
9405 If set to ON Squid will automatically retry requests when
9406 receiving an error response with status 403 (Forbidden),
9407 500 (Internal Error), 501 or 503 (Service not available).
9408 Status 502 and 504 (Gateway errors) are always retried.
9410 This is mainly useful if you are in a complex cache hierarchy to
9411 work around access control errors.
9413 NOTE: This retry will attempt to find another working destination.
9414 Which is different from the server which just failed.
9417 NAME: as_whois_server
9419 LOC: Config.as_whois_server
9420 DEFAULT: whois.ra.net
9422 WHOIS server to query for AS numbers. NOTE: AS numbers are
9423 queried only when Squid starts up, not for every request.
9428 LOC: Config.onoff.offline
9431 Enable this option and Squid will never try to validate cached
9435 NAME: uri_whitespace
9436 TYPE: uri_whitespace
9437 LOC: Config.uri_whitespace
9440 What to do with requests that have whitespace characters in the
9443 strip: The whitespace characters are stripped out of the URL.
9444 This is the behavior recommended by RFC2396 and RFC3986
9445 for tolerant handling of generic URI.
9446 NOTE: This is one difference between generic URI and HTTP URLs.
9448 deny: The request is denied. The user receives an "Invalid
9450 This is the behaviour recommended by RFC2616 for safe
9451 handling of HTTP request URL.
9453 allow: The request is allowed and the URI is not changed. The
9454 whitespace characters remain in the URI. Note the
9455 whitespace is passed to redirector processes if they
9457 Note this may be considered a violation of RFC2616
9458 request parsing where whitespace is prohibited in the
9461 encode: The request is allowed and the whitespace characters are
9462 encoded according to RFC1738.
9464 chop: The request is allowed and the URI is chopped at the
9468 NOTE the current Squid implementation of encode and chop violates
9469 RFC2616 by not using a 301 redirect after altering the URL.
9474 LOC: Config.chroot_dir
9477 Specifies a directory where Squid should do a chroot() while
9478 initializing. This also causes Squid to fully drop root
9479 privileges after initializing. This means, for example, if you
9480 use a HTTP port less than 1024 and try to reconfigure, you may
9481 get an error saying that Squid can not open the port.
9484 NAME: balance_on_multiple_ip
9486 LOC: Config.onoff.balance_on_multiple_ip
9489 Modern IP resolvers in squid sort lookup results by preferred access.
9490 By default squid will use these IP in order and only rotates to
9491 the next listed when the most preffered fails.
9493 Some load balancing servers based on round robin DNS have been
9494 found not to preserve user session state across requests
9495 to different IP addresses.
9497 Enabling this directive Squid rotates IP's per request.
9500 NAME: pipeline_prefetch
9501 TYPE: pipelinePrefetch
9502 LOC: Config.pipeline_max_prefetch
9504 DEFAULT_DOC: Do not pre-parse pipelined requests.
9506 HTTP clients may send a pipeline of 1+N requests to Squid using a
9507 single connection, without waiting for Squid to respond to the first
9508 of those requests. This option limits the number of concurrent
9509 requests Squid will try to handle in parallel. If set to N, Squid
9510 will try to receive and process up to 1+N requests on the same
9511 connection concurrently.
9513 Defaults to 0 (off) for bandwidth management and access logging
9516 NOTE: pipelining requires persistent connections to clients.
9518 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
9521 NAME: high_response_time_warning
9524 LOC: Config.warnings.high_rptm
9526 DEFAULT_DOC: disabled.
9528 If the one-minute median response time exceeds this value,
9529 Squid prints a WARNING with debug level 0 to get the
9530 administrators attention. The value is in milliseconds.
9533 NAME: high_page_fault_warning
9535 LOC: Config.warnings.high_pf
9537 DEFAULT_DOC: disabled.
9539 If the one-minute average page fault rate exceeds this
9540 value, Squid prints a WARNING with debug level 0 to get
9541 the administrators attention. The value is in page faults
9545 NAME: high_memory_warning
9547 LOC: Config.warnings.high_memory
9548 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
9550 DEFAULT_DOC: disabled.
9552 If the memory usage (as determined by gnumalloc, if available and used)
9553 exceeds this amount, Squid prints a WARNING with debug level 0 to get
9554 the administrators attention.
9556 # TODO: link high_memory_warning to mempools?
9558 NAME: sleep_after_fork
9559 COMMENT: (microseconds)
9561 LOC: Config.sleep_after_fork
9564 When this is set to a non-zero value, the main Squid process
9565 sleeps the specified number of microseconds after a fork()
9566 system call. This sleep may help the situation where your
9567 system reports fork() failures due to lack of (virtual)
9568 memory. Note, however, if you have a lot of child
9569 processes, these sleep delays will add up and your
9570 Squid will not service requests for some amount of time
9571 until all the child processes have been started.
9572 On Windows value less then 1000 (1 milliseconds) are
9576 NAME: windows_ipaddrchangemonitor
9577 IFDEF: _SQUID_WINDOWS_
9581 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
9583 On Windows Squid by default will monitor IP address changes and will
9584 reconfigure itself after any detected event. This is very useful for
9585 proxies connected to internet with dial-up interfaces.
9586 In some cases (a Proxy server acting as VPN gateway is one) it could be
9587 desiderable to disable this behaviour setting this to 'off'.
9588 Note: after changing this, Squid service must be restarted.
9593 IFDEF: USE_SQUID_EUI
9595 LOC: Eui::TheConfig.euiLookup
9597 Whether to lookup the EUI or MAC address of a connected client.
9600 NAME: max_filedescriptors max_filedesc
9603 DEFAULT_DOC: Use operating system limits set by ulimit.
9604 LOC: Config.max_filedescriptors
9606 Reduce the maximum number of filedescriptors supported below
9607 the usual operating system defaults.
9609 Remove from squid.conf to inherit the current ulimit setting.
9611 Note: Changing this requires a restart of Squid. Also
9612 not all I/O types supports large values (eg on Windows).
9615 NAME: force_request_body_continuation
9617 LOC: Config.accessList.forceRequestBodyContinuation
9619 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
9621 This option controls how Squid handles data upload requests from HTTP
9622 and FTP agents that require a "Please Continue" control message response
9623 to actually send the request body to Squid. It is mostly useful in
9624 adaptation environments.
9626 When Squid receives an HTTP request with an "Expect: 100-continue"
9627 header or an FTP upload command (e.g., STOR), Squid normally sends the
9628 request headers or FTP command information to an adaptation service (or
9629 peer) and waits for a response. Most adaptation services (and some
9630 broken peers) may not respond to Squid at that stage because they may
9631 decide to wait for the HTTP request body or FTP data transfer. However,
9632 that request body or data transfer may never come because Squid has not
9633 responded with the HTTP 100 or FTP 150 (Please Continue) control message
9634 to the request sender yet!
9636 An allow match tells Squid to respond with the HTTP 100 or FTP 150
9637 (Please Continue) control message on its own, before forwarding the
9638 request to an adaptation service or peer. Such a response usually forces
9639 the request sender to proceed with sending the body. A deny match tells
9640 Squid to delay that control response until the origin server confirms
9641 that the request body is needed. Delaying is the default behavior.
projects / thirdparty / squid.git / blob