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 version= 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.
380 OPTIONS FOR AUTHENTICATION
381 -----------------------------------------------------------------------------
390 This is used to define parameters for the various authentication
391 schemes supported by Squid.
393 format: auth_param scheme parameter [setting]
395 The order in which authentication schemes are presented to the client is
396 dependent on the order the scheme first appears in config file. IE
397 has a bug (it's not RFC 2617 compliant) in that it will use the basic
398 scheme if basic is the first entry presented, even if more secure
399 schemes are presented. For now use the order in the recommended
400 settings section below. If other browsers have difficulties (don't
401 recognize the schemes offered even if you are using basic) either
402 put basic first, or disable the other schemes (by commenting out their
405 Once an authentication scheme is fully configured, it can only be
406 shutdown by shutting squid down and restarting. Changes can be made on
407 the fly and activated with a reconfigure. I.E. You can change to a
408 different helper, but not unconfigure the helper completely.
410 Please note that while this directive defines how Squid processes
411 authentication it does not automatically activate authentication.
412 To use authentication you must in addition make use of ACLs based
413 on login name in http_access (proxy_auth, proxy_auth_regex or
414 external with %LOGIN used in the format tag). The browser will be
415 challenged for authentication on the first such acl encountered
416 in http_access processing and will also be re-challenged for new
417 login credentials if the request is being denied by a proxy_auth
420 WARNING: authentication can't be used in a transparently intercepting
421 proxy as the client then thinks it is talking to an origin server and
422 not the proxy. This is a limitation of bending the TCP/IP protocol to
423 transparently intercepting port 80, not a limitation in Squid.
424 Ports flagged 'transparent', 'intercept', or 'tproxy' have
425 authentication disabled.
427 === Parameters common to all schemes. ===
430 Specifies the command for the external authenticator.
432 By default, each authentication scheme is not used unless a
433 program is specified.
435 See http://wiki.squid-cache.org/Features/AddonHelpers for
436 more details on helper operations and creating your own.
439 Specifies a string to be append to request line format for
440 the authentication helper. "Quoted" format values may contain
441 spaces and logformat %macros. In theory, any logformat %macro
442 can be used. In practice, a %macro expands as a dash (-) if
443 the helper request is sent before the required macro
444 information is available to Squid.
446 By default, Squid uses request formats provided in
447 scheme-specific examples below (search for %credentials).
449 The expanded key_extras value is added to the Squid credentials
450 cache and, hence, will affect authentication. It can be used to
451 autenticate different users with identical user names (e.g.,
452 when user authentication depends on http_port).
454 Avoid adding frequently changing information to key_extras. For
455 example, if you add user source IP, and it changes frequently
456 in your environment, then max_user_ip ACL is going to treat
457 every user+IP combination as a unique "user", breaking the ACL
458 and wasting a lot of memory on those user records. It will also
459 force users to authenticate from scratch whenever their IP
463 Specifies the protection scope (aka realm name) which is to be
464 reported to the client for the authentication scheme. It is
465 commonly part of the text the user will see when prompted for
466 their username and password.
468 For Basic the default is "Squid proxy-caching web server".
469 For Digest there is no default, this parameter is mandatory.
470 For NTLM and Negotiate this parameter is ignored.
472 "children" numberofchildren [startup=N] [idle=N] [concurrency=N] [queue-size=N]
474 The maximum number of authenticator processes to spawn. If
475 you start too few Squid will have to wait for them to process
476 a backlog of credential verifications, slowing it down. When
477 password verifications are done via a (slow) network you are
478 likely to need lots of authenticator processes.
480 The startup= and idle= options permit some skew in the exact
481 amount run. A minimum of startup=N will begin during startup
482 and reconfigure. Squid will start more in groups of up to
483 idle=N in an attempt to meet traffic needs and to keep idle=N
484 free above those traffic needs up to the maximum.
486 The concurrency= option sets the number of concurrent requests
487 the helper can process. The default of 0 is used for helpers
488 who only supports one request at a time. Setting this to a
489 number greater than 0 changes the protocol used to include a
490 channel ID field first on the request/response line, allowing
491 multiple requests to be sent to the same helper in parallel
492 without waiting for the response.
494 Concurrency must not be set unless it's known the helper
495 supports the input format with channel-ID fields.
497 The queue-size= option sets the maximum number of queued
498 requests. If the queued requests exceed queue size for more
499 than 3 minutes then squid aborts its operation.
500 The default value is set to 2*numberofchildren/
502 NOTE: NTLM and Negotiate schemes do not support concurrency
503 in the Squid code module even though some helpers can.
506 IF HAVE_AUTH_MODULE_BASIC
507 === Basic authentication parameters ===
510 HTTP uses iso-latin-1 as character set, while some
511 authentication backends such as LDAP expects UTF-8. If this is
512 set to on Squid will translate the HTTP iso-latin-1 charset to
513 UTF-8 before sending the username and password to the helper.
515 "credentialsttl" timetolive
516 Specifies how long squid assumes an externally validated
517 username:password pair is valid for - in other words how
518 often the helper program is called for that user. Set this
519 low to force revalidation with short lived passwords.
521 NOTE: setting this high does not impact your susceptibility
522 to replay attacks unless you are using an one-time password
523 system (such as SecureID). If you are using such a system,
524 you will be vulnerable to replay attacks unless you also
525 use the max_user_ip ACL in an http_access rule.
527 "casesensitive" on|off
528 Specifies if usernames are case sensitive. Most user databases
529 are case insensitive allowing the same username to be spelled
530 using both lower and upper case letters, but some are case
531 sensitive. This makes a big difference for user_max_ip ACL
532 processing and similar.
535 IF HAVE_AUTH_MODULE_DIGEST
536 === Digest authentication parameters ===
539 HTTP uses iso-latin-1 as character set, while some
540 authentication backends such as LDAP expects UTF-8. If this is
541 set to on Squid will translate the HTTP iso-latin-1 charset to
542 UTF-8 before sending the username and password to the helper.
544 "nonce_garbage_interval" timeinterval
545 Specifies the interval that nonces that have been issued
546 to client_agent's are checked for validity.
548 "nonce_max_duration" timeinterval
549 Specifies the maximum length of time a given nonce will be
552 "nonce_max_count" number
553 Specifies the maximum number of times a given nonce can be
556 "nonce_strictness" on|off
557 Determines if squid requires strict increment-by-1 behavior
558 for nonce counts, or just incrementing (off - for use when
559 user agents generate nonce counts that occasionally miss 1
560 (ie, 1,2,4,6)). Default off.
562 "check_nonce_count" on|off
563 This directive if set to off can disable the nonce count check
564 completely to work around buggy digest qop implementations in
565 certain mainstream browser versions. Default on to check the
566 nonce count to protect from authentication replay attacks.
568 "post_workaround" on|off
569 This is a workaround to certain buggy browsers who send an
570 incorrect request digest in POST requests when reusing the
571 same nonce as acquired earlier on a GET request.
574 IF HAVE_AUTH_MODULE_NEGOTIATE
575 === Negotiate authentication parameters ===
578 If you experience problems with PUT/POST requests when using
579 the this authentication scheme then you can try setting this
580 to off. This will cause Squid to forcibly close the connection
581 on the initial request where the browser asks which schemes
582 are supported by the proxy.
585 IF HAVE_AUTH_MODULE_NTLM
586 === NTLM authentication parameters ===
589 If you experience problems with PUT/POST requests when using
590 the this authentication scheme then you can try setting this
591 to off. This will cause Squid to forcibly close the connection
592 on the initial request where the browser asks which schemes
593 are supported by the proxy.
596 === Example Configuration ===
598 This configuration displays the recommended authentication scheme
599 order from most to least secure with recommended minimum configuration
600 settings for each scheme:
602 #auth_param negotiate program <uncomment and complete this line to activate>
603 #auth_param negotiate children 20 startup=0 idle=1
604 #auth_param negotiate keep_alive on
606 #auth_param digest program <uncomment and complete this line to activate>
607 #auth_param digest children 20 startup=0 idle=1
608 #auth_param digest realm Squid proxy-caching web server
609 #auth_param digest nonce_garbage_interval 5 minutes
610 #auth_param digest nonce_max_duration 30 minutes
611 #auth_param digest nonce_max_count 50
613 #auth_param ntlm program <uncomment and complete this line to activate>
614 #auth_param ntlm children 20 startup=0 idle=1
615 #auth_param ntlm keep_alive on
617 #auth_param basic program <uncomment and complete this line>
618 #auth_param basic children 5 startup=5 idle=1
619 #auth_param basic realm Squid proxy-caching web server
620 #auth_param basic credentialsttl 2 hours
623 NAME: authenticate_cache_garbage_interval
626 LOC: Config.authenticateGCInterval
628 The time period between garbage collection across the username cache.
629 This is a trade-off between memory utilization (long intervals - say
630 2 days) and CPU (short intervals - say 1 minute). Only change if you
634 NAME: authenticate_ttl
637 LOC: Config.authenticateTTL
639 The time a user & their credentials stay in the logged in
640 user cache since their last request. When the garbage
641 interval passes, all user credentials that have passed their
642 TTL are removed from memory.
645 NAME: authenticate_ip_ttl
647 LOC: Config.authenticateIpTTL
650 If you use proxy authentication and the 'max_user_ip' ACL,
651 this directive controls how long Squid remembers the IP
652 addresses associated with each user. Use a small value
653 (e.g., 60 seconds) if your users might change addresses
654 quickly, as is the case with dialup. You might be safe
655 using a larger value (e.g., 2 hours) in a corporate LAN
656 environment with relatively static address assignments.
661 -----------------------------------------------------------------------------
664 NAME: external_acl_type
665 TYPE: externalAclHelper
666 LOC: Config.externalAclHelperList
669 This option defines external acl classes using a helper program
670 to look up the status
672 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
676 ttl=n TTL in seconds for cached results (defaults to 3600
680 TTL for cached negative lookups (default same
683 grace=n Percentage remaining of TTL where a refresh of a
684 cached entry should be initiated without needing to
685 wait for a new reply. (default is for no grace period)
687 cache=n Limit the result cache size, default is 262144.
688 The expanded FORMAT value is used as the cache key, so
689 if the details in FORMAT are highly variable a larger
690 cache may be needed to produce reduction in helper load.
693 Maximum number of acl helper processes spawned to service
694 external acl lookups of this type. (default 20)
697 Minimum number of acl helper processes to spawn during
698 startup and reconfigure to service external acl lookups
699 of this type. (default 0)
702 Number of acl helper processes to keep ahead of traffic
703 loads. Squid will spawn this many at once whenever load
704 rises above the capabilities of existing processes.
705 Up to the value of children-max. (default 1)
707 concurrency=n concurrency level per process. Only used with helpers
708 capable of processing more than one query at a time.
710 queue-size=N The queue-size= option sets the maximum number of queued
711 requests. If the queued requests exceed queue size
713 The default value is set to 2*children-max.
715 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers.
717 ipv4 / ipv6 IP protocol used to communicate with this helper.
718 The default is to auto-detect IPv6 and use it when available.
721 FORMAT specifications
723 %LOGIN Authenticated user login name
724 %EXT_USER Username from previous external acl
725 %EXT_LOG Log details from previous external acl
726 %EXT_TAG Tag from previous external acl
727 %IDENT Ident user name
729 %SRCPORT Client source port
732 %PROTO Requested URL scheme
734 %PATH Requested URL path
735 %METHOD Request method
736 %MYADDR Squid interface address
737 %MYPORT Squid http_port number
738 %PATH Requested URL-path (including query-string if any)
739 %USER_CERT SSL User certificate in PEM format
740 %USER_CERTCHAIN SSL User certificate chain in PEM format
741 %USER_CERT_xx SSL User certificate subject attribute xx
742 %USER_CA_CERT_xx SSL User certificate issuer attribute xx
743 %ssl::>sni SSL client SNI sent to Squid
744 %ssl::<cert_subject SSL server certificate DN
745 %ssl::<cert_issuer SSL server certificate issuer DN
747 %>{Header} HTTP request header "Header"
749 HTTP request header "Hdr" list member "member"
751 HTTP request header list member using ; as
752 list separator. ; can be any non-alphanumeric
755 %<{Header} HTTP reply header "Header"
757 HTTP reply header "Hdr" list member "member"
759 HTTP reply header list member using ; as
760 list separator. ; can be any non-alphanumeric
763 %ACL The name of the ACL being tested.
764 %DATA The ACL arguments. If not used then any arguments
765 is automatically added at the end of the line
767 NOTE: this will encode the arguments as one token,
768 whereas the default will pass each separately.
770 %% The percent sign. Useful for helpers which need
771 an unchanging input format.
774 General request syntax:
776 [channel-ID] FORMAT-values [acl-values ...]
779 FORMAT-values consists of transaction details expanded with
780 whitespace separation per the config file FORMAT specification
781 using the FORMAT macros listed above.
783 acl-values consists of any string specified in the referencing
784 config 'acl ... external' line. see the "acl external" directive.
786 Request values sent to the helper are URL escaped to protect
787 each value in requests against whitespaces.
789 If using protocol=2.5 then the request sent to the helper is not
790 URL escaped to protect against whitespace.
792 NOTE: protocol=3.0 is deprecated as no longer necessary.
794 When using the concurrency= option the protocol is changed by
795 introducing a query channel tag in front of the request/response.
796 The query channel tag is a number between 0 and concurrency-1.
797 This value must be echoed back unchanged to Squid as the first part
798 of the response relating to its request.
801 The helper receives lines expanded per the above format specification
802 and for each input line returns 1 line starting with OK/ERR/BH result
803 code and optionally followed by additional keywords with more details.
806 General result syntax:
808 [channel-ID] result keyword=value ...
810 Result consists of one of the codes:
813 the ACL test produced a match.
816 the ACL test does not produce a match.
819 An internal error occurred in the helper, preventing
820 a result being identified.
822 The meaning of 'a match' is determined by your squid.conf
823 access control configuration. See the Squid wiki for details.
827 user= The users name (login)
829 password= The users password (for login= cache_peer option)
831 message= Message describing the reason for this response.
832 Available as %o in error pages.
833 Useful on (ERR and BH results).
835 tag= Apply a tag to a request. Only sets a tag once,
836 does not alter existing tags.
838 log= String to be logged in access.log. Available as
839 %ea in logformat specifications.
841 clt_conn_tag= Associates a TAG with the client TCP connection.
842 Please see url_rewrite_program related documentation
845 Any keywords may be sent on any response whether OK, ERR or BH.
847 All response keyword values need to be a single token with URL
848 escaping, or enclosed in double quotes (") and escaped using \ on
849 any double quotes or \ characters within the value. The wrapping
850 double quotes are removed before the value is interpreted by Squid.
851 \r and \n are also replace by CR and LF.
853 Some example key values:
857 user="J. \"Bob\" Smith"
864 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
865 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
866 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
867 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
868 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
871 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
872 DEFAULT: localhost src 127.0.0.1/32 ::1
873 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
874 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
876 Defining an Access List
878 Every access list definition must begin with an aclname and acltype,
879 followed by either type-specific arguments or a quoted filename that
882 acl aclname acltype argument ...
883 acl aclname acltype "file" ...
885 When using "file", the file should contain one item per line.
887 Some acl types supports options which changes their default behaviour.
888 The available options are:
890 -i,+i By default, regular expressions are CASE-SENSITIVE. To make them
891 case-insensitive, use the -i option. To return case-sensitive
892 use the +i option between patterns, or make a new ACL line
895 -n Disable lookups and address type conversions. If lookup or
896 conversion is required because the parameter type (IP or
897 domain name) does not match the message address type (domain
898 name or IP), then the ACL would immediately declare a mismatch
899 without any warnings or lookups.
901 -- Used to stop processing all options, in the case the first acl
902 value has '-' character as first character (for example the '-'
903 is a valid domain name)
905 Some acl types require suspending the current request in order
906 to access some external data source.
907 Those which do are marked with the tag [slow], those which
908 don't are marked as [fast].
909 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
910 for further information
912 ***** ACL TYPES AVAILABLE *****
914 acl aclname src ip-address/mask ... # clients IP address [fast]
915 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
916 acl aclname dst [-n] ip-address/mask ... # URL host's IP address [slow]
917 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
919 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
920 # The arp ACL requires the special configure option --enable-arp-acl.
921 # Furthermore, the ARP ACL code is not portable to all operating systems.
922 # It works on Linux, Solaris, Windows, FreeBSD, and some
923 # other *BSD variants.
926 # NOTE: Squid can only determine the MAC address for clients that are on
927 # the same subnet. If the client is on a different subnet,
928 # then Squid cannot find out its MAC address.
930 acl aclname srcdomain .foo.com ...
931 # reverse lookup, from client IP [slow]
932 acl aclname dstdomain [-n] .foo.com ...
933 # Destination server from URL [fast]
934 acl aclname srcdom_regex [-i] \.foo\.com ...
935 # regex matching client name [slow]
936 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
937 # regex matching server [fast]
939 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
940 # based URL is used and no match is found. The name "none" is used
941 # if the reverse lookup fails.
943 acl aclname src_as number ...
944 acl aclname dst_as number ...
946 # Except for access control, AS numbers can be used for
947 # routing of requests to specific caches. Here's an
948 # example for routing all requests for AS#1241 and only
949 # those to mycache.mydomain.net:
950 # acl asexample dst_as 1241
951 # cache_peer_access mycache.mydomain.net allow asexample
952 # cache_peer_access mycache_mydomain.net deny all
954 acl aclname peername myPeer ...
956 # match against a named cache_peer entry
957 # set unique name= on cache_peer lines for reliable use.
959 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
969 # h1:m1 must be less than h2:m2
971 acl aclname url_regex [-i] ^http:// ...
972 # regex matching on whole URL [fast]
973 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
974 # regex matching on URL login field
975 acl aclname urlpath_regex [-i] \.gif$ ...
976 # regex matching on URL path [fast]
978 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
980 acl aclname localport 3128 ... # TCP port the client connected to [fast]
981 # NP: for interception mode this is usually '80'
983 acl aclname myportname 3128 ... # *_port name [fast]
985 acl aclname proto HTTP FTP ... # request protocol [fast]
987 acl aclname method GET POST ... # HTTP request method [fast]
989 acl aclname http_status 200 301 500- 400-403 ...
990 # status code in reply [fast]
992 acl aclname browser [-i] regexp ...
993 # pattern match on User-Agent header (see also req_header below) [fast]
995 acl aclname referer_regex [-i] regexp ...
996 # pattern match on Referer header [fast]
997 # Referer is highly unreliable, so use with care
999 acl aclname ident username ...
1000 acl aclname ident_regex [-i] pattern ...
1001 # string match on ident output [slow]
1002 # use REQUIRED to accept any non-null ident.
1004 acl aclname proxy_auth [-i] username ...
1005 acl aclname proxy_auth_regex [-i] pattern ...
1006 # perform http authentication challenge to the client and match against
1007 # supplied credentials [slow]
1009 # takes a list of allowed usernames.
1010 # use REQUIRED to accept any valid username.
1012 # Will use proxy authentication in forward-proxy scenarios, and plain
1013 # http authenticaiton in reverse-proxy scenarios
1015 # NOTE: when a Proxy-Authentication header is sent but it is not
1016 # needed during ACL checking the username is NOT logged
1019 # NOTE: proxy_auth requires a EXTERNAL authentication program
1020 # to check username/password combinations (see
1021 # auth_param directive).
1023 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
1024 # as the browser needs to be configured for using a proxy in order
1025 # to respond to proxy authentication.
1027 acl aclname snmp_community string ...
1028 # A community string to limit access to your SNMP Agent [fast]
1031 # acl snmppublic snmp_community public
1033 acl aclname maxconn number
1034 # This will be matched when the client's IP address has
1035 # more than <number> TCP connections established. [fast]
1036 # NOTE: This only measures direct TCP links so X-Forwarded-For
1037 # indirect clients are not counted.
1039 acl aclname max_user_ip [-s] number
1040 # This will be matched when the user attempts to log in from more
1041 # than <number> different ip addresses. The authenticate_ip_ttl
1042 # parameter controls the timeout on the ip entries. [fast]
1043 # If -s is specified the limit is strict, denying browsing
1044 # from any further IP addresses until the ttl has expired. Without
1045 # -s Squid will just annoy the user by "randomly" denying requests.
1046 # (the counter is reset each time the limit is reached and a
1047 # request is denied)
1048 # NOTE: in acceleration mode or where there is mesh of child proxies,
1049 # clients may appear to come from multiple addresses if they are
1050 # going through proxy farms, so a limit of 1 may cause user problems.
1052 acl aclname random probability
1053 # Pseudo-randomly match requests. Based on the probability given.
1054 # Probability may be written as a decimal (0.333), fraction (1/3)
1055 # or ratio of matches:non-matches (3:5).
1057 acl aclname req_mime_type [-i] mime-type ...
1058 # regex match against the mime type of the request generated
1059 # by the client. Can be used to detect file upload or some
1060 # types HTTP tunneling requests [fast]
1061 # NOTE: This does NOT match the reply. You cannot use this
1062 # to match the returned file type.
1064 acl aclname req_header header-name [-i] any\.regex\.here
1065 # regex match against any of the known request headers. May be
1066 # thought of as a superset of "browser", "referer" and "mime-type"
1069 acl aclname rep_mime_type [-i] mime-type ...
1070 # regex match against the mime type of the reply received by
1071 # squid. Can be used to detect file download or some
1072 # types HTTP tunneling requests. [fast]
1073 # NOTE: This has no effect in http_access rules. It only has
1074 # effect in rules that affect the reply data stream such as
1075 # http_reply_access.
1077 acl aclname rep_header header-name [-i] any\.regex\.here
1078 # regex match against any of the known reply headers. May be
1079 # thought of as a superset of "browser", "referer" and "mime-type"
1082 acl aclname external class_name [arguments...]
1083 # external ACL lookup via a helper class defined by the
1084 # external_acl_type directive [slow]
1086 acl aclname user_cert attribute values...
1087 # match against attributes in a user SSL certificate
1088 # attribute is one of DN/C/O/CN/L/ST [fast]
1090 acl aclname ca_cert attribute values...
1091 # match against attributes a users issuing CA SSL certificate
1092 # attribute is one of DN/C/O/CN/L/ST [fast]
1094 acl aclname ext_user username ...
1095 acl aclname ext_user_regex [-i] pattern ...
1096 # string match on username returned by external acl helper [slow]
1097 # use REQUIRED to accept any non-null user name.
1099 acl aclname tag tagvalue ...
1100 # string match on tag returned by external acl helper [fast]
1101 # DEPRECATED. Only the first tag will match with this ACL.
1102 # Use the 'note' ACL instead for handling multiple tag values.
1104 acl aclname hier_code codename ...
1105 # string match against squid hierarchy code(s); [fast]
1106 # e.g., DIRECT, PARENT_HIT, NONE, etc.
1108 # NOTE: This has no effect in http_access rules. It only has
1109 # effect in rules that affect the reply data stream such as
1110 # http_reply_access.
1112 acl aclname note name [value ...]
1113 # match transaction annotation [fast]
1114 # Without values, matches any annotation with a given name.
1115 # With value(s), matches any annotation with a given name that
1116 # also has one of the given values.
1117 # Names and values are compared using a string equality test.
1118 # Annotation sources include note and adaptation_meta directives
1119 # as well as helper and eCAP responses.
1121 acl aclname adaptation_service service ...
1122 # Matches the name of any icap_service, ecap_service,
1123 # adaptation_service_set, or adaptation_service_chain that Squid
1124 # has used (or attempted to use) for the master transaction.
1125 # This ACL must be defined after the corresponding adaptation
1126 # service is named in squid.conf. This ACL is usable with
1127 # adaptation_meta because it starts matching immediately after
1128 # the service has been selected for adaptation.
1131 acl aclname ssl_error errorname
1132 # match against SSL certificate validation error [fast]
1134 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1137 # The following can be used as shortcuts for certificate properties:
1138 # [ssl::]certHasExpired: the "not after" field is in the past
1139 # [ssl::]certNotYetValid: the "not before" field is in the future
1140 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1141 # [ssl::]certSelfSigned: The certificate is self signed.
1142 # [ssl::]certDomainMismatch: The certificate CN domain does not
1143 # match the name the name of the host we are connecting to.
1145 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1146 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1147 # predefined ACLs, just like the 'all' ACL.
1149 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1150 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1152 acl aclname server_cert_fingerprint [-sha1] fingerprint
1153 # match against server SSL certificate fingerprint [fast]
1155 # The fingerprint is the digest of the DER encoded version
1156 # of the whole certificate. The user should use the form: XX:XX:...
1157 # Optional argument specifies the digest algorithm to use.
1158 # The SHA1 digest algorithm is the default and is currently
1159 # the only algorithm supported (-sha1).
1161 acl aclname at_step step
1162 # match against the current step during ssl_bump evaluation [fast]
1163 # Never matches and should not be used outside the ssl_bump context.
1165 # At each SslBump step, Squid evaluates ssl_bump directives to find
1166 # the next bumping action (e.g., peek or splice). Valid SslBump step
1167 # values and the corresponding ssl_bump evaluation moments are:
1168 # SslBump1: After getting TCP-level and HTTP CONNECT info.
1169 # SslBump2: After getting SSL Client Hello info.
1170 # SslBump3: After getting SSL Server Hello info.
1172 acl aclname any-of acl1 acl2 ...
1173 # match any one of the acls [fast or slow]
1174 # The first matching ACL stops further ACL evaluation.
1176 # ACLs from multiple any-of lines with the same name are ORed.
1177 # For example, A = (a1 or a2) or (a3 or a4) can be written as
1178 # acl A any-of a1 a2
1179 # acl A any-of a3 a4
1181 # This group ACL is fast if all evaluated ACLs in the group are fast
1182 # and slow otherwise.
1184 acl aclname all-of acl1 acl2 ...
1185 # match all of the acls [fast or slow]
1186 # The first mismatching ACL stops further ACL evaluation.
1188 # ACLs from multiple all-of lines with the same name are ORed.
1189 # For example, B = (b1 and b2) or (b3 and b4) can be written as
1190 # acl B all-of b1 b2
1191 # acl B all-of b3 b4
1193 # This group ACL is fast if all evaluated ACLs in the group are fast
1194 # and slow otherwise.
1197 acl macaddress arp 09:00:2b:23:45:67
1198 acl myexample dst_as 1241
1199 acl password proxy_auth REQUIRED
1200 acl fileupload req_mime_type -i ^multipart/form-data$
1201 acl javascript rep_mime_type -i ^application/x-javascript$
1205 # Recommended minimum configuration:
1208 # Example rule allowing access from your local networks.
1209 # Adapt to list your (internal) IP networks from where browsing
1211 acl localnet src 0.0.0.1-0.255.255.255 # RFC 1122 "this" network (LAN)
1212 acl localnet src 10.0.0.0/8 # RFC 1918 local private network (LAN)
1213 acl localnet src 100.64.0.0/10 # RFC 6598 shared address space (CGN)
1214 acl localhet src 169.254.0.0/16 # RFC 3927 link-local (directly plugged) machines
1215 acl localnet src 172.16.0.0/12 # RFC 1918 local private network (LAN)
1216 acl localnet src 192.168.0.0/16 # RFC 1918 local private network (LAN)
1217 acl localnet src fc00::/7 # RFC 4193 local private network range
1218 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1220 acl SSL_ports port 443
1221 acl Safe_ports port 80 # http
1222 acl Safe_ports port 21 # ftp
1223 acl Safe_ports port 443 # https
1224 acl Safe_ports port 70 # gopher
1225 acl Safe_ports port 210 # wais
1226 acl Safe_ports port 1025-65535 # unregistered ports
1227 acl Safe_ports port 280 # http-mgmt
1228 acl Safe_ports port 488 # gss-http
1229 acl Safe_ports port 591 # filemaker
1230 acl Safe_ports port 777 # multiling http
1231 acl CONNECT method CONNECT
1235 NAME: proxy_protocol_access
1237 LOC: Config.accessList.proxyProtocol
1239 DEFAULT_DOC: all TCP connections to ports with require-proxy-header will be denied
1241 Determine which client proxies can be trusted to provide correct
1242 information regarding real client IP address using PROXY protocol.
1244 Requests may pass through a chain of several other proxies
1245 before reaching us. The original source details may by sent in:
1246 * HTTP message Forwarded header, or
1247 * HTTP message X-Forwarded-For header, or
1248 * PROXY protocol connection header.
1250 This directive is solely for validating new PROXY protocol
1251 connections received from a port flagged with require-proxy-header.
1252 It is checked only once after TCP connection setup.
1254 A deny match results in TCP connection closure.
1256 An allow match is required for Squid to permit the corresponding
1257 TCP connection, before Squid even looks for HTTP request headers.
1258 If there is an allow match, Squid starts using PROXY header information
1259 to determine the source address of the connection for all future ACL
1260 checks, logging, etc.
1262 SECURITY CONSIDERATIONS:
1264 Any host from which we accept client IP details can place
1265 incorrect information in the relevant header, and Squid
1266 will use the incorrect information as if it were the
1267 source address of the request. This may enable remote
1268 hosts to bypass any access control restrictions that are
1269 based on the client's source addresses.
1271 This clause only supports fast acl types.
1272 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1275 NAME: follow_x_forwarded_for
1277 IFDEF: FOLLOW_X_FORWARDED_FOR
1278 LOC: Config.accessList.followXFF
1279 DEFAULT_IF_NONE: deny all
1280 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1282 Determine which client proxies can be trusted to provide correct
1283 information regarding real client IP address.
1285 Requests may pass through a chain of several other proxies
1286 before reaching us. The original source details may by sent in:
1287 * HTTP message Forwarded header, or
1288 * HTTP message X-Forwarded-For header, or
1289 * PROXY protocol connection header.
1291 PROXY protocol connections are controlled by the proxy_protocol_access
1292 directive which is checked before this.
1294 If a request reaches us from a source that is allowed by this
1295 directive, then we trust the information it provides regarding
1296 the IP of the client it received from (if any).
1298 For the purpose of ACLs used in this directive the src ACL type always
1299 matches the address we are testing and srcdomain matches its rDNS.
1301 On each HTTP request Squid checks for X-Forwarded-For header fields.
1302 If found the header values are iterated in reverse order and an allow
1303 match is required for Squid to continue on to the next value.
1304 The verification ends when a value receives a deny match, cannot be
1305 tested, or there are no more values to test.
1306 NOTE: Squid does not yet follow the Forwarded HTTP header.
1308 The end result of this process is an IP address that we will
1309 refer to as the indirect client address. This address may
1310 be treated as the client address for access control, ICAP, delay
1311 pools and logging, depending on the acl_uses_indirect_client,
1312 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1313 log_uses_indirect_client and tproxy_uses_indirect_client options.
1315 This clause only supports fast acl types.
1316 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1318 SECURITY CONSIDERATIONS:
1320 Any host from which we accept client IP details can place
1321 incorrect information in the relevant header, and Squid
1322 will use the incorrect information as if it were the
1323 source address of the request. This may enable remote
1324 hosts to bypass any access control restrictions that are
1325 based on the client's source addresses.
1329 acl localhost src 127.0.0.1
1330 acl my_other_proxy srcdomain .proxy.example.com
1331 follow_x_forwarded_for allow localhost
1332 follow_x_forwarded_for allow my_other_proxy
1335 NAME: acl_uses_indirect_client
1338 IFDEF: FOLLOW_X_FORWARDED_FOR
1340 LOC: Config.onoff.acl_uses_indirect_client
1342 Controls whether the indirect client address
1343 (see follow_x_forwarded_for) is used instead of the
1344 direct client address in acl matching.
1346 NOTE: maxconn ACL considers direct TCP links and indirect
1347 clients will always have zero. So no match.
1350 NAME: delay_pool_uses_indirect_client
1353 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1355 LOC: Config.onoff.delay_pool_uses_indirect_client
1357 Controls whether the indirect client address
1358 (see follow_x_forwarded_for) is used instead of the
1359 direct client address in delay pools.
1362 NAME: log_uses_indirect_client
1365 IFDEF: FOLLOW_X_FORWARDED_FOR
1367 LOC: Config.onoff.log_uses_indirect_client
1369 Controls whether the indirect client address
1370 (see follow_x_forwarded_for) is used instead of the
1371 direct client address in the access log.
1374 NAME: tproxy_uses_indirect_client
1377 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1379 LOC: Config.onoff.tproxy_uses_indirect_client
1381 Controls whether the indirect client address
1382 (see follow_x_forwarded_for) is used instead of the
1383 direct client address when spoofing the outgoing client.
1385 This has no effect on requests arriving in non-tproxy
1388 SECURITY WARNING: Usage of this option is dangerous
1389 and should not be used trivially. Correct configuration
1390 of follow_x_forewarded_for with a limited set of trusted
1391 sources is required to prevent abuse of your proxy.
1394 NAME: spoof_client_ip
1396 LOC: Config.accessList.spoof_client_ip
1398 DEFAULT_DOC: Allow spoofing on all TPROXY traffic.
1400 Control client IP address spoofing of TPROXY traffic based on
1401 defined access lists.
1403 spoof_client_ip allow|deny [!]aclname ...
1405 If there are no "spoof_client_ip" lines present, the default
1406 is to "allow" spoofing of any suitable request.
1408 Note that the cache_peer "no-tproxy" option overrides this ACL.
1410 This clause supports fast acl types.
1411 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1416 LOC: Config.accessList.http
1417 DEFAULT_IF_NONE: deny all
1418 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1420 Allowing or Denying access based on defined access lists
1422 To allow or deny a message received on an HTTP, HTTPS, or FTP port:
1423 http_access allow|deny [!]aclname ...
1425 NOTE on default values:
1427 If there are no "access" lines present, the default is to deny
1430 If none of the "access" lines cause a match, the default is the
1431 opposite of the last line in the list. If the last line was
1432 deny, the default is allow. Conversely, if the last line
1433 is allow, the default will be deny. For these reasons, it is a
1434 good idea to have an "deny all" entry at the end of your access
1435 lists to avoid potential confusion.
1437 This clause supports both fast and slow acl types.
1438 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1443 # Recommended minimum Access Permission configuration:
1445 # Deny requests to certain unsafe ports
1446 http_access deny !Safe_ports
1448 # Deny CONNECT to other than secure SSL ports
1449 http_access deny CONNECT !SSL_ports
1451 # Only allow cachemgr access from localhost
1452 http_access allow localhost manager
1453 http_access deny manager
1455 # We strongly recommend the following be uncommented to protect innocent
1456 # web applications running on the proxy server who think the only
1457 # one who can access services on "localhost" is a local user
1458 #http_access deny to_localhost
1461 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1464 # Example rule allowing access from your local networks.
1465 # Adapt localnet in the ACL section to list your (internal) IP networks
1466 # from where browsing should be allowed
1467 http_access allow localnet
1468 http_access allow localhost
1470 # And finally deny all other access to this proxy
1471 http_access deny all
1475 NAME: adapted_http_access http_access2
1477 LOC: Config.accessList.adapted_http
1479 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1481 Allowing or Denying access based on defined access lists
1483 Essentially identical to http_access, but runs after redirectors
1484 and ICAP/eCAP adaptation. Allowing access control based on their
1487 If not set then only http_access is used.
1490 NAME: http_reply_access
1492 LOC: Config.accessList.reply
1494 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1496 Allow replies to client requests. This is complementary to http_access.
1498 http_reply_access allow|deny [!] aclname ...
1500 NOTE: if there are no access lines present, the default is to allow
1503 If none of the access lines cause a match the opposite of the
1504 last line will apply. Thus it is good practice to end the rules
1505 with an "allow all" or "deny all" entry.
1507 This clause supports both fast and slow acl types.
1508 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1513 LOC: Config.accessList.icp
1515 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1517 Allowing or Denying access to the ICP port based on defined
1520 icp_access allow|deny [!]aclname ...
1522 NOTE: The default if no icp_access lines are present is to
1523 deny all traffic. This default may cause problems with peers
1526 This clause only supports fast acl types.
1527 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1529 # Allow ICP queries from local networks only
1530 #icp_access allow localnet
1531 #icp_access deny all
1537 LOC: Config.accessList.htcp
1539 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1541 Allowing or Denying access to the HTCP port based on defined
1544 htcp_access allow|deny [!]aclname ...
1546 See also htcp_clr_access for details on access control for
1547 cache purge (CLR) HTCP messages.
1549 NOTE: The default if no htcp_access lines are present is to
1550 deny all traffic. This default may cause problems with peers
1551 using the htcp option.
1553 This clause only supports fast acl types.
1554 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1556 # Allow HTCP queries from local networks only
1557 #htcp_access allow localnet
1558 #htcp_access deny all
1561 NAME: htcp_clr_access
1564 LOC: Config.accessList.htcp_clr
1566 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1568 Allowing or Denying access to purge content using HTCP based
1569 on defined access lists.
1570 See htcp_access for details on general HTCP access control.
1572 htcp_clr_access allow|deny [!]aclname ...
1574 This clause only supports fast acl types.
1575 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1577 # Allow HTCP CLR requests from trusted peers
1578 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1579 htcp_clr_access allow htcp_clr_peer
1580 htcp_clr_access deny all
1585 LOC: Config.accessList.miss
1587 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1589 Determins whether network access is permitted when satisfying a request.
1592 to force your neighbors to use you as a sibling instead of
1595 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1596 miss_access deny !localclients
1597 miss_access allow all
1599 This means only your local clients are allowed to fetch relayed/MISS
1600 replies from the network and all other clients can only fetch cached
1603 The default for this setting allows all clients who passed the
1604 http_access rules to relay via this proxy.
1606 This clause only supports fast acl types.
1607 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1610 NAME: ident_lookup_access
1614 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1615 LOC: Ident::TheConfig.identLookup
1617 A list of ACL elements which, if matched, cause an ident
1618 (RFC 931) lookup to be performed for this request. For
1619 example, you might choose to always perform ident lookups
1620 for your main multi-user Unix boxes, but not for your Macs
1621 and PCs. By default, ident lookups are not performed for
1624 To enable ident lookups for specific client addresses, you
1625 can follow this example:
1627 acl ident_aware_hosts src 198.168.1.0/24
1628 ident_lookup_access allow ident_aware_hosts
1629 ident_lookup_access deny all
1631 Only src type ACL checks are fully supported. A srcdomain
1632 ACL might work at times, but it will not always provide
1635 This clause only supports fast acl types.
1636 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1639 NAME: reply_body_max_size
1640 COMMENT: size [acl acl...]
1643 DEFAULT_DOC: No limit is applied.
1644 LOC: Config.ReplyBodySize
1646 This option specifies the maximum size of a reply body. It can be
1647 used to prevent users from downloading very large files, such as
1648 MP3's and movies. When the reply headers are received, the
1649 reply_body_max_size lines are processed, and the first line where
1650 all (if any) listed ACLs are true is used as the maximum body size
1653 This size is checked twice. First when we get the reply headers,
1654 we check the content-length value. If the content length value exists
1655 and is larger than the allowed size, the request is denied and the
1656 user receives an error message that says "the request or reply
1657 is too large." If there is no content-length, and the reply
1658 size exceeds this limit, the client's connection is just closed
1659 and they will receive a partial reply.
1661 WARNING: downstream caches probably can not detect a partial reply
1662 if there is no content-length header, so they will cache
1663 partial responses and give them out as hits. You should NOT
1664 use this option if you have downstream caches.
1666 WARNING: A maximum size smaller than the size of squid's error messages
1667 will cause an infinite loop and crash squid. Ensure that the smallest
1668 non-zero value you use is greater that the maximum header size plus
1669 the size of your largest error page.
1671 If you set this parameter none (the default), there will be
1674 Configuration Format is:
1675 reply_body_max_size SIZE UNITS [acl ...]
1677 reply_body_max_size 10 MB
1681 NAME: on_unsupported_protocol
1682 TYPE: on_unsupported_protocol
1683 LOC: Config.accessList.on_unsupported_protocol
1685 DEFAULT_DOC: Respond with an error message to unidentifiable traffic
1687 Determines Squid behavior when encountering strange requests at the
1688 beginning of an accepted TCP connection. This is especially useful in
1689 interception environments where Squid is likely to see connections for
1690 unsupported protocols that Squid should either terminate or tunnel at
1693 on_unsupported_protocol <action> [!]acl ...
1695 The first matching action wins.
1697 Supported actions are:
1699 tunnel: Establish a TCP connection with the intended server and
1700 blindly shovel TCP packets between the client and server.
1702 respond: Respond with an error message, using the transfer protocol
1703 for the Squid port that received the request (e.g., HTTP
1704 for connections intercepted at the http_port). This is the
1707 Currently, this directive is ignored for non-intercepted connections
1708 because Squid cannot know what their intended destination is.
1711 # define what Squid errors indicate receiving non-HTTP traffic:
1712 acl foreignProtocol squid_error ERR_PROTOCOL_UNKNOWN ERR_TOO_BIG
1713 # define what Squid errors indicate receiving nothing:
1714 acl serverTalksFirstProtocol squid_error ERR_REQUEST_START_TIMEOUT
1715 # tunnel everything that does not look like HTTP:
1716 on_unsupported_protocol tunnel foreignProtocol
1717 # tunnel if we think the client waits for the server to talk first:
1718 on_unsupported_protocol tunnel serverTalksFirstProtocol
1719 # in all other error cases, just send an HTTP "error page" response:
1720 on_unsupported_protocol respond all
1722 See also: squid_error ACL
1727 -----------------------------------------------------------------------------
1730 NAME: http_port ascii_port
1735 Usage: port [mode] [options]
1736 hostname:port [mode] [options]
1737 1.2.3.4:port [mode] [options]
1739 The socket addresses where Squid will listen for HTTP client
1740 requests. You may specify multiple socket addresses.
1741 There are three forms: port alone, hostname with port, and
1742 IP address with port. If you specify a hostname or IP
1743 address, Squid binds the socket to that specific
1744 address. Most likely, you do not need to bind to a specific
1745 address, so you can use the port number alone.
1747 If you are running Squid in accelerator mode, you
1748 probably want to listen on port 80 also, or instead.
1750 The -a command line option may be used to specify additional
1751 port(s) where Squid listens for proxy request. Such ports will
1752 be plain proxy ports with no options.
1754 You may specify multiple socket addresses on multiple lines.
1758 intercept Support for IP-Layer interception of
1759 outgoing requests without browser settings.
1760 NP: disables authentication and IPv6 on the port.
1762 tproxy Support Linux TPROXY for spoofing outgoing
1763 connections using the client IP address.
1764 NP: disables authentication and maybe IPv6 on the port.
1766 accel Accelerator / reverse proxy mode
1768 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1769 establish secure connection with the client and with
1770 the server, decrypt HTTPS messages as they pass through
1771 Squid, and treat them as unencrypted HTTP messages,
1772 becoming the man-in-the-middle.
1774 The ssl_bump option is required to fully enable
1775 bumping of CONNECT requests.
1777 Omitting the mode flag causes default forward proxy mode to be used.
1780 Accelerator Mode Options:
1782 defaultsite=domainname
1783 What to use for the Host: header if it is not present
1784 in a request. Determines what site (not origin server)
1785 accelerators should consider the default.
1787 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1789 protocol= Protocol to reconstruct accelerated and intercepted
1790 requests with. Defaults to HTTP/1.1 for http_port and
1791 HTTPS/1.1 for https_port.
1792 When an unsupported value is configured Squid will
1793 produce a FATAL error.
1794 Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
1796 vport Virtual host port support. Using the http_port number
1797 instead of the port passed on Host: headers.
1799 vport=NN Virtual host port support. Using the specified port
1800 number instead of the port passed on Host: headers.
1803 Act as if this Squid is the origin server.
1804 This currently means generate new Date: and Expires:
1805 headers on HIT instead of adding Age:.
1807 ignore-cc Ignore request Cache-Control headers.
1809 WARNING: This option violates HTTP specifications if
1810 used in non-accelerator setups.
1812 allow-direct Allow direct forwarding in accelerator mode. Normally
1813 accelerated requests are denied direct forwarding as if
1814 never_direct was used.
1816 WARNING: this option opens accelerator mode to security
1817 vulnerabilities usually only affecting in interception
1818 mode. Make sure to protect forwarding with suitable
1819 http_access rules when using this.
1822 SSL Bump Mode Options:
1823 In addition to these options ssl-bump requires TLS/SSL options.
1825 generate-host-certificates[=<on|off>]
1826 Dynamically create SSL server certificates for the
1827 destination hosts of bumped CONNECT requests.When
1828 enabled, the cert and key options are used to sign
1829 generated certificates. Otherwise generated
1830 certificate will be selfsigned.
1831 If there is a CA certificate lifetime of the generated
1832 certificate equals lifetime of the CA certificate. If
1833 generated certificate is selfsigned lifetime is three
1835 This option is enabled by default when ssl-bump is used.
1836 See the ssl-bump option above for more information.
1838 dynamic_cert_mem_cache_size=SIZE
1839 Approximate total RAM size spent on cached generated
1840 certificates. If set to zero, caching is disabled. The
1841 default value is 4MB.
1845 cert= Path to SSL certificate (PEM format).
1847 key= Path to SSL private key file (PEM format)
1848 if not specified, the certificate file is
1849 assumed to be a combined certificate and
1852 version= The version of SSL/TLS supported
1853 1 automatic (default)
1859 cipher= Colon separated list of supported ciphers.
1860 NOTE: some ciphers such as EDH ciphers depend on
1861 additional settings. If those settings are
1862 omitted the ciphers may be silently ignored
1863 by the OpenSSL library.
1865 options= Various SSL implementation options. The most important
1868 NO_SSLv3 Disallow the use of SSLv3
1870 NO_TLSv1 Disallow the use of TLSv1.0
1872 NO_TLSv1_1 Disallow the use of TLSv1.1
1874 NO_TLSv1_2 Disallow the use of TLSv1.2
1877 Always create a new key when using
1878 temporary/ephemeral DH key exchanges
1881 Disable use of RFC5077 session tickets.
1882 Some servers may have problems
1883 understanding the TLS extension due
1884 to ambiguous specification in RFC4507.
1886 ALL Enable various bug workarounds
1887 suggested as "harmless" by OpenSSL
1888 Be warned that this reduces SSL/TLS
1889 strength to some attacks.
1891 See the OpenSSL SSL_CTX_set_options documentation for a
1894 clientca= File containing the list of CAs to use when
1895 requesting a client certificate.
1897 cafile= File containing additional CA certificates to
1898 use when verifying client certificates. If unset
1899 clientca will be used.
1901 capath= Directory containing additional CA certificates
1902 and CRL lists to use when verifying client certificates.
1904 crlfile= File of additional CRL lists to use when verifying
1905 the client certificate, in addition to CRLs stored in
1906 the capath. Implies VERIFY_CRL flag below.
1908 dhparams= File containing DH parameters for temporary/ephemeral
1909 DH key exchanges. See OpenSSL documentation for details
1910 on how to create this file.
1911 WARNING: EDH ciphers will be silently disabled if this
1914 sslflags= Various flags modifying the use of SSL:
1916 Don't request client certificates
1917 immediately, but wait until acl processing
1918 requires a certificate (not yet implemented).
1920 Don't use the default CA lists built in
1923 Don't allow for session reuse. Each connection
1924 will result in a new SSL session.
1926 Verify CRL lists when accepting client
1929 Verify CRL lists for all certificates in the
1930 client certificate chain.
1932 sslcontext= SSL session ID context identifier.
1936 connection-auth[=on|off]
1937 use connection-auth=off to tell Squid to prevent
1938 forwarding Microsoft connection oriented authentication
1939 (NTLM, Negotiate and Kerberos)
1941 disable-pmtu-discovery=
1942 Control Path-MTU discovery usage:
1943 off lets OS decide on what to do (default).
1944 transparent disable PMTU discovery when transparent
1946 always disable always PMTU discovery.
1948 In many setups of transparently intercepting proxies
1949 Path-MTU discovery can not work on traffic towards the
1950 clients. This is the case when the intercepting device
1951 does not fully track connections and fails to forward
1952 ICMP must fragment messages to the cache server. If you
1953 have such setup and experience that certain clients
1954 sporadically hang or never complete requests set
1955 disable-pmtu-discovery option to 'transparent'.
1957 name= Specifies a internal name for the port. Defaults to
1958 the port specification (port or addr:port)
1960 tcpkeepalive[=idle,interval,timeout]
1961 Enable TCP keepalive probes of idle connections.
1962 In seconds; idle is the initial time before TCP starts
1963 probing the connection, interval how often to probe, and
1964 timeout the time before giving up.
1966 require-proxy-header
1967 Require PROXY protocol version 1 or 2 connections.
1968 The proxy_protocol_access is required to whitelist
1969 downstream proxies which can be trusted.
1971 If you run Squid on a dual-homed machine with an internal
1972 and an external interface we recommend you to specify the
1973 internal address:port in http_port. This way Squid will only be
1974 visible on the internal address.
1978 # Squid normally listens to port 3128
1979 http_port @DEFAULT_HTTP_PORT@
1989 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1991 The socket address where Squid will listen for client requests made
1992 over TLS or SSL connections. Commonly referred to as HTTPS.
1994 This is most useful for situations where you are running squid in
1995 accelerator mode and you want to do the SSL work at the accelerator level.
1997 You may specify multiple socket addresses on multiple lines,
1998 each with their own SSL certificate and/or options.
2002 accel Accelerator / reverse proxy mode
2004 intercept Support for IP-Layer interception of
2005 outgoing requests without browser settings.
2006 NP: disables authentication and IPv6 on the port.
2008 tproxy Support Linux TPROXY for spoofing outgoing
2009 connections using the client IP address.
2010 NP: disables authentication and maybe IPv6 on the port.
2012 ssl-bump For each intercepted connection allowed by ssl_bump
2013 ACLs, establish a secure connection with the client and with
2014 the server, decrypt HTTPS messages as they pass through
2015 Squid, and treat them as unencrypted HTTP messages,
2016 becoming the man-in-the-middle.
2018 An "ssl_bump server-first" match is required to
2019 fully enable bumping of intercepted SSL connections.
2021 Requires tproxy or intercept.
2023 Omitting the mode flag causes default forward proxy mode to be used.
2026 See http_port for a list of generic options
2031 cert= Path to SSL certificate (PEM format).
2033 key= Path to SSL private key file (PEM format)
2034 if not specified, the certificate file is
2035 assumed to be a combined certificate and
2038 version= The version of SSL/TLS supported
2039 1 automatic (default)
2043 cipher= Colon separated list of supported ciphers.
2045 options= Various SSL engine options. The most important
2048 NO_SSLv3 Disallow the use of SSLv3
2050 NO_TLSv1 Disallow the use of TLSv1.0
2052 NO_TLSv1_1 Disallow the use of TLSv1.1
2054 NO_TLSv1_2 Disallow the use of TLSv1.2
2057 Always create a new key when using
2058 temporary/ephemeral DH key exchanges
2061 Disable use of RFC5077 session tickets.
2062 Some servers may have problems
2063 understanding the TLS extension due
2064 to ambiguous specification in RFC4507.
2066 ALL Enable various bug workarounds
2067 suggested as "harmless" by OpenSSL
2068 Be warned that this reduces SSL/TLS
2069 strength to some attacks.
2071 See the OpenSSL SSL_CTX_set_options documentation for a
2074 clientca= File containing the list of CAs to use when
2075 requesting a client certificate.
2077 cafile= File containing additional CA certificates to
2078 use when verifying client certificates. If unset
2079 clientca will be used.
2081 capath= Directory containing additional CA certificates
2082 and CRL lists to use when verifying client certificates.
2084 crlfile= File of additional CRL lists to use when verifying
2085 the client certificate, in addition to CRLs stored in
2086 the capath. Implies VERIFY_CRL flag below.
2088 dhparams= File containing DH parameters for temporary/ephemeral
2091 sslflags= Various flags modifying the use of SSL:
2093 Don't request client certificates
2094 immediately, but wait until acl processing
2095 requires a certificate (not yet implemented).
2097 Don't use the default CA lists built in
2100 Don't allow for session reuse. Each connection
2101 will result in a new SSL session.
2103 Verify CRL lists when accepting client
2106 Verify CRL lists for all certificates in the
2107 client certificate chain.
2109 sslcontext= SSL session ID context identifier.
2111 generate-host-certificates[=<on|off>]
2112 Dynamically create SSL server certificates for the
2113 destination hosts of bumped SSL requests.When
2114 enabled, the cert and key options are used to sign
2115 generated certificates. Otherwise generated
2116 certificate will be selfsigned.
2117 If there is CA certificate life time of generated
2118 certificate equals lifetime of CA certificate. If
2119 generated certificate is selfsigned lifetime is three
2121 This option is enabled by default when SslBump is used.
2122 See the sslBump option above for more information.
2124 dynamic_cert_mem_cache_size=SIZE
2125 Approximate total RAM size spent on cached generated
2126 certificates. If set to zero, caching is disabled. The
2127 default value is 4MB.
2129 See http_port for a list of available options.
2137 Enables Native FTP proxy by specifying the socket address where Squid
2138 listens for FTP client requests. See http_port directive for various
2139 ways to specify the listening address and mode.
2141 Usage: ftp_port address [mode] [options]
2143 WARNING: This is a new, experimental, complex feature that has seen
2144 limited production exposure. Some Squid modules (e.g., caching) do not
2145 currently work with native FTP proxying, and many features have not
2146 even been tested for compatibility. Test well before deploying!
2148 Native FTP proxying differs substantially from proxying HTTP requests
2149 with ftp:// URIs because Squid works as an FTP server and receives
2150 actual FTP commands (rather than HTTP requests with FTP URLs).
2152 Native FTP commands accepted at ftp_port are internally converted or
2153 wrapped into HTTP-like messages. The same happens to Native FTP
2154 responses received from FTP origin servers. Those HTTP-like messages
2155 are shoveled through regular access control and adaptation layers
2156 between the FTP client and the FTP origin server. This allows Squid to
2157 examine, adapt, block, and log FTP exchanges. Squid reuses most HTTP
2158 mechanisms when shoveling wrapped FTP messages. For example,
2159 http_access and adaptation_access directives are used.
2163 intercept Same as http_port intercept. The FTP origin address is
2164 determined based on the intended destination of the
2165 intercepted connection.
2167 tproxy Support Linux TPROXY for spoofing outgoing
2168 connections using the client IP address.
2169 NP: disables authentication and maybe IPv6 on the port.
2171 By default (i.e., without an explicit mode option), Squid extracts the
2172 FTP origin address from the login@origin parameter of the FTP USER
2173 command. Many popular FTP clients support such native FTP proxying.
2177 name=token Specifies an internal name for the port. Defaults to
2178 the port address. Usable with myportname ACL.
2181 Enables tracking of FTP directories by injecting extra
2182 PWD commands and adjusting Request-URI (in wrapping
2183 HTTP requests) to reflect the current FTP server
2184 directory. Tracking is disabled by default.
2186 protocol=FTP Protocol to reconstruct accelerated and intercepted
2187 requests with. Defaults to FTP. No other accepted
2188 values have been tested with. An unsupported value
2189 results in a FATAL error. Accepted values are FTP,
2190 HTTP (or HTTP/1.1), and HTTPS (or HTTPS/1.1).
2192 Other http_port modes and options that are not specific to HTTP and
2193 HTTPS may also work.
2196 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
2199 LOC: Ip::Qos::TheConfig.tosToServer
2201 Allows you to select a TOS/Diffserv value for packets outgoing
2202 on the server side, based on an ACL.
2204 tcp_outgoing_tos ds-field [!]aclname ...
2206 Example where normal_service_net uses the TOS value 0x00
2207 and good_service_net uses 0x20
2209 acl normal_service_net src 10.0.0.0/24
2210 acl good_service_net src 10.0.1.0/24
2211 tcp_outgoing_tos 0x00 normal_service_net
2212 tcp_outgoing_tos 0x20 good_service_net
2214 TOS/DSCP values really only have local significance - so you should
2215 know what you're specifying. For more information, see RFC2474,
2216 RFC2475, and RFC3260.
2218 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2219 "default" to use whatever default your host has. Note that in
2220 practice often only multiples of 4 is usable as the two rightmost bits
2221 have been redefined for use by ECN (RFC 3168 section 23.1).
2223 Processing proceeds in the order specified, and stops at first fully
2226 Only fast ACLs are supported.
2229 NAME: clientside_tos
2232 LOC: Ip::Qos::TheConfig.tosToClient
2234 Allows you to select a TOS/Diffserv value for packets being transmitted
2235 on the client-side, based on an ACL.
2237 clientside_tos ds-field [!]aclname ...
2239 Example where normal_service_net uses the TOS value 0x00
2240 and good_service_net uses 0x20
2242 acl normal_service_net src 10.0.0.0/24
2243 acl good_service_net src 10.0.1.0/24
2244 clientside_tos 0x00 normal_service_net
2245 clientside_tos 0x20 good_service_net
2247 Note: This feature is incompatible with qos_flows. Any TOS values set here
2248 will be overwritten by TOS values in qos_flows.
2251 NAME: tcp_outgoing_mark
2253 IFDEF: SO_MARK&&USE_LIBCAP
2255 LOC: Ip::Qos::TheConfig.nfmarkToServer
2257 Allows you to apply a Netfilter mark value to outgoing packets
2258 on the server side, based on an ACL.
2260 tcp_outgoing_mark mark-value [!]aclname ...
2262 Example where normal_service_net uses the mark value 0x00
2263 and good_service_net uses 0x20
2265 acl normal_service_net src 10.0.0.0/24
2266 acl good_service_net src 10.0.1.0/24
2267 tcp_outgoing_mark 0x00 normal_service_net
2268 tcp_outgoing_mark 0x20 good_service_net
2270 Only fast ACLs are supported.
2273 NAME: clientside_mark
2275 IFDEF: SO_MARK&&USE_LIBCAP
2277 LOC: Ip::Qos::TheConfig.nfmarkToClient
2279 Allows you to apply a Netfilter mark value to packets being transmitted
2280 on the client-side, based on an ACL.
2282 clientside_mark mark-value [!]aclname ...
2284 Example where normal_service_net uses the mark value 0x00
2285 and good_service_net uses 0x20
2287 acl normal_service_net src 10.0.0.0/24
2288 acl good_service_net src 10.0.1.0/24
2289 clientside_mark 0x00 normal_service_net
2290 clientside_mark 0x20 good_service_net
2292 Note: This feature is incompatible with qos_flows. Any mark values set here
2293 will be overwritten by mark values in qos_flows.
2300 LOC: Ip::Qos::TheConfig
2302 Allows you to select a TOS/DSCP value to mark outgoing
2303 connections to the client, based on where the reply was sourced.
2304 For platforms using netfilter, allows you to set a netfilter mark
2305 value instead of, or in addition to, a TOS value.
2307 By default this functionality is disabled. To enable it with the default
2308 settings simply use "qos_flows mark" or "qos_flows tos". Default
2309 settings will result in the netfilter mark or TOS value being copied
2310 from the upstream connection to the client. Note that it is the connection
2311 CONNMARK value not the packet MARK value that is copied.
2313 It is not currently possible to copy the mark or TOS value from the
2314 client to the upstream connection request.
2316 TOS values really only have local significance - so you should
2317 know what you're specifying. For more information, see RFC2474,
2318 RFC2475, and RFC3260.
2320 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
2321 in practice often only multiples of 4 is usable as the two rightmost bits
2322 have been redefined for use by ECN (RFC 3168 section 23.1).
2324 Mark values can be any unsigned 32-bit integer value.
2326 This setting is configured by setting the following values:
2328 tos|mark Whether to set TOS or netfilter mark values
2330 local-hit=0xFF Value to mark local cache hits.
2332 sibling-hit=0xFF Value to mark hits from sibling peers.
2334 parent-hit=0xFF Value to mark hits from parent peers.
2336 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2337 over the preserve-miss feature (see below), unless
2338 mask is specified, in which case only the bits
2339 specified in the mask are written.
2341 The TOS variant of the following features are only possible on Linux
2342 and require your kernel to be patched with the TOS preserving ZPH
2343 patch, available from http://zph.bratcheda.org
2344 No patch is needed to preserve the netfilter mark, which will work
2345 with all variants of netfilter.
2347 disable-preserve-miss
2348 This option disables the preservation of the TOS or netfilter
2349 mark. By default, the existing TOS or netfilter mark value of
2350 the response coming from the remote server will be retained
2351 and masked with miss-mark.
2352 NOTE: in the case of a netfilter mark, the mark must be set on
2353 the connection (using the CONNMARK target) not on the packet
2357 Allows you to mask certain bits in the TOS or mark value
2358 received from the remote server, before copying the value to
2359 the TOS sent towards clients.
2360 Default for tos: 0xFF (TOS from server is not changed).
2361 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2363 All of these features require the --enable-zph-qos compilation flag
2364 (enabled by default). Netfilter marking also requires the
2365 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2366 libcap 2.09+ (--with-libcap).
2370 NAME: tcp_outgoing_address
2373 DEFAULT_DOC: Address selection is performed by the operating system.
2374 LOC: Config.accessList.outgoing_address
2376 Allows you to map requests to different outgoing IP addresses
2377 based on the username or source address of the user making
2380 tcp_outgoing_address ipaddr [[!]aclname] ...
2383 Forwarding clients with dedicated IPs for certain subnets.
2385 acl normal_service_net src 10.0.0.0/24
2386 acl good_service_net src 10.0.2.0/24
2388 tcp_outgoing_address 2001:db8::c001 good_service_net
2389 tcp_outgoing_address 10.1.0.2 good_service_net
2391 tcp_outgoing_address 2001:db8::beef normal_service_net
2392 tcp_outgoing_address 10.1.0.1 normal_service_net
2394 tcp_outgoing_address 2001:db8::1
2395 tcp_outgoing_address 10.1.0.3
2397 Processing proceeds in the order specified, and stops at first fully
2400 Squid will add an implicit IP version test to each line.
2401 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2402 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2405 NOTE: The use of this directive using client dependent ACLs is
2406 incompatible with the use of server side persistent connections. To
2407 ensure correct results it is best to set server_persistent_connections
2408 to off when using this directive in such configurations.
2410 NOTE: The use of this directive to set a local IP on outgoing TCP links
2411 is incompatible with using TPROXY to set client IP out outbound TCP links.
2412 When needing to contact peers use the no-tproxy cache_peer option and the
2413 client_dst_passthru directive re-enable normal forwarding such as this.
2417 NAME: host_verify_strict
2420 LOC: Config.onoff.hostStrictVerify
2422 Regardless of this option setting, when dealing with intercepted
2423 traffic, Squid always verifies that the destination IP address matches
2424 the Host header domain or IP (called 'authority form URL').
2426 This enforcement is performed to satisfy a MUST-level requirement in
2427 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2428 authority of the origin server or gateway given by the original URL".
2431 Squid always responds with an HTTP 409 (Conflict) error
2432 page and logs a security warning if there is no match.
2434 Squid verifies that the destination IP address matches
2435 the Host header for forward-proxy and reverse-proxy traffic
2436 as well. For those traffic types, Squid also enables the
2437 following checks, comparing the corresponding Host header
2438 and Request-URI components:
2440 * The host names (domain or IP) must be identical,
2441 but valueless or missing Host header disables all checks.
2442 For the two host names to match, both must be either IP
2445 * Port numbers must be identical, but if a port is missing
2446 the scheme-default port is assumed.
2449 When set to OFF (the default):
2450 Squid allows suspicious requests to continue but logs a
2451 security warning and blocks caching of the response.
2453 * Forward-proxy traffic is not checked at all.
2455 * Reverse-proxy traffic is not checked at all.
2457 * Intercepted traffic which passes verification is handled
2458 according to client_dst_passthru.
2460 * Intercepted requests which fail verification are sent
2461 to the client original destination instead of DIRECT.
2462 This overrides 'client_dst_passthru off'.
2464 For now suspicious intercepted CONNECT requests are always
2465 responded to with an HTTP 409 (Conflict) error page.
2470 As described in CVE-2009-0801 when the Host: header alone is used
2471 to determine the destination of a request it becomes trivial for
2472 malicious scripts on remote websites to bypass browser same-origin
2473 security policy and sandboxing protections.
2475 The cause of this is that such applets are allowed to perform their
2476 own HTTP stack, in which case the same-origin policy of the browser
2477 sandbox only verifies that the applet tries to contact the same IP
2478 as from where it was loaded at the IP level. The Host: header may
2479 be different from the connected IP and approved origin.
2483 NAME: client_dst_passthru
2486 LOC: Config.onoff.client_dst_passthru
2488 With NAT or TPROXY intercepted traffic Squid may pass the request
2489 directly to the original client destination IP or seek a faster
2490 source using the HTTP Host header.
2492 Using Host to locate alternative servers can provide faster
2493 connectivity with a range of failure recovery options.
2494 But can also lead to connectivity trouble when the client and
2495 server are attempting stateful interactions unaware of the proxy.
2497 This option (on by default) prevents alternative DNS entries being
2498 located to send intercepted traffic DIRECT to an origin server.
2499 The clients original destination IP and port will be used instead.
2501 Regardless of this option setting, when dealing with intercepted
2502 traffic Squid will verify the Host: header and any traffic which
2503 fails Host verification will be treated as if this option were ON.
2505 see host_verify_strict for details on the verification process.
2510 -----------------------------------------------------------------------------
2513 NAME: tls_outgoing_options
2514 IFDEF: USE_GNUTLS||USE_OPENSSL
2515 TYPE: securePeerOptions
2517 LOC: Security::ProxyOutgoingConfig
2519 disable Do not support https:// URLs.
2521 cert=/path/to/client/certificate
2522 A client TLS certificate to use when connecting.
2524 key=/path/to/client/private_key
2525 The private TLS key corresponding to the cert= above.
2526 If key= is not specified cert= is assumed to reference
2527 a PEM file containing both the certificate and the key.
2530 The TLS/SSL version to use when connecting
2531 1 = automatic (default)
2537 cipher=... The list of valid TLS ciphers to use.
2539 options=... Specify various TLS/SSL implementation options:
2541 NO_SSLv3 Disallow the use of SSLv3
2543 NO_TLSv1 Disallow the use of TLSv1.0
2545 NO_TLSv1_1 Disallow the use of TLSv1.1
2547 NO_TLSv1_2 Disallow the use of TLSv1.2
2550 Always create a new key when using
2551 temporary/ephemeral DH key exchanges
2554 Disable use of RFC5077 session tickets.
2555 Some servers may have problems
2556 understanding the TLS extension due
2557 to ambiguous specification in RFC4507.
2559 ALL Enable various bug workarounds
2560 suggested as "harmless" by OpenSSL
2561 Be warned that this reduces SSL/TLS
2562 strength to some attacks.
2564 See the OpenSSL SSL_CTX_set_options documentation for a
2567 cafile=... A file containing additional CA certificates to use
2568 when verifying the peer certificate.
2570 capath=... A directory containing additional CA certificates to
2571 use when verifying the peer certificate.
2573 crlfile=... A certificate revocation list file to use when
2574 verifying the peer certificate.
2576 flags=... Specify various flags modifying the TLS implementation:
2579 Accept certificates even if they fail to
2582 Don't use the default CA list built in
2585 Don't verify the peer certificate
2586 matches the server name
2588 domain= The peer name as advertised in its certificate.
2589 Used for verifying the correctness of the received peer
2590 certificate. If not specified the peer hostname will be
2596 -----------------------------------------------------------------------------
2599 NAME: ssl_unclean_shutdown
2603 LOC: Config.SSL.unclean_shutdown
2605 Some browsers (especially MSIE) bugs out on SSL shutdown
2612 LOC: Config.SSL.ssl_engine
2615 The OpenSSL engine to use. You will need to set this if you
2616 would like to use hardware SSL acceleration for example.
2619 NAME: sslproxy_session_ttl
2622 LOC: Config.SSL.session_ttl
2625 Sets the timeout value for SSL sessions
2628 NAME: sslproxy_session_cache_size
2631 LOC: Config.SSL.sessionCacheSize
2634 Sets the cache size to use for ssl session
2637 NAME: sslproxy_cert_sign_hash
2640 LOC: Config.SSL.certSignHash
2643 Sets the hashing algorithm to use when signing generated certificates.
2644 Valid algorithm names depend on the OpenSSL library used. The following
2645 names are usually available: sha1, sha256, sha512, and md5. Please see
2646 your OpenSSL library manual for the available hashes. By default, Squids
2647 that support this option use sha256 hashes.
2649 Squid does not forcefully purge cached certificates that were generated
2650 with an algorithm other than the currently configured one. They remain
2651 in the cache, subject to the regular cache eviction policy, and become
2652 useful if the algorithm changes again.
2657 TYPE: sslproxy_ssl_bump
2658 LOC: Config.accessList.ssl_bump
2659 DEFAULT_DOC: Become a TCP tunnel without decrypting proxied traffic.
2662 This option is consulted when a CONNECT request is received on
2663 an http_port (or a new connection is intercepted at an
2664 https_port), provided that port was configured with an ssl-bump
2665 flag. The subsequent data on the connection is either treated as
2666 HTTPS and decrypted OR tunneled at TCP level without decryption,
2667 depending on the first matching bumping "action".
2669 ssl_bump <action> [!]acl ...
2671 The following bumping actions are currently supported:
2674 Become a TCP tunnel without decrypting proxied traffic.
2675 This is the default action.
2678 Establish a secure connection with the server and, using a
2679 mimicked server certificate, with the client.
2682 Receive client (step SslBump1) or server (step SslBump2)
2683 certificate while preserving the possibility of splicing the
2684 connection. Peeking at the server certificate (during step 2)
2685 usually precludes bumping of the connection at step 3.
2688 Receive client (step SslBump1) or server (step SslBump2)
2689 certificate while preserving the possibility of bumping the
2690 connection. Staring at the server certificate (during step 2)
2691 usually precludes splicing of the connection at step 3.
2694 Close client and server connections.
2696 Backward compatibility actions available at step SslBump1:
2699 Bump the connection. Establish a secure connection with the
2700 client first, then connect to the server. This old mode does
2701 not allow Squid to mimic server SSL certificate and does not
2702 work with intercepted SSL connections.
2705 Bump the connection. Establish a secure connection with the
2706 server first, then establish a secure connection with the
2707 client, using a mimicked server certificate. Works with both
2708 CONNECT requests and intercepted SSL connections, but does
2709 not allow to make decisions based on SSL handshake info.
2712 Decide whether to bump or splice the connection based on
2713 client-to-squid and server-to-squid SSL hello messages.
2717 Same as the "splice" action.
2719 All ssl_bump rules are evaluated at each of the supported bumping
2720 steps. Rules with actions that are impossible at the current step are
2721 ignored. The first matching ssl_bump action wins and is applied at the
2722 end of the current step. If no rules match, the splice action is used.
2723 See the at_step ACL for a list of the supported SslBump steps.
2725 This clause supports both fast and slow acl types.
2726 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2728 See also: http_port ssl-bump, https_port ssl-bump, and acl at_step.
2731 # Example: Bump all requests except those originating from
2732 # localhost or those going to example.com.
2734 acl broken_sites dstdomain .example.com
2735 ssl_bump splice localhost
2736 ssl_bump splice broken_sites
2740 NAME: sslproxy_cert_error
2743 DEFAULT_DOC: Server certificate errors terminate the transaction.
2744 LOC: Config.ssl_client.cert_error
2747 Use this ACL to bypass server certificate validation errors.
2749 For example, the following lines will bypass all validation errors
2750 when talking to servers for example.com. All other
2751 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2753 acl BrokenButTrustedServers dstdomain example.com
2754 sslproxy_cert_error allow BrokenButTrustedServers
2755 sslproxy_cert_error deny all
2757 This clause only supports fast acl types.
2758 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2759 Using slow acl types may result in server crashes
2761 Without this option, all server certificate validation errors
2762 terminate the transaction to protect Squid and the client.
2764 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2765 but should not happen unless your OpenSSL library is buggy.
2768 Bypassing validation errors is dangerous because an
2769 error usually implies that the server cannot be trusted
2770 and the connection may be insecure.
2772 See also: sslproxy_flags and DONT_VERIFY_PEER.
2775 NAME: sslproxy_cert_sign
2778 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2779 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2780 POSTSCRIPTUM: signTrusted all
2781 TYPE: sslproxy_cert_sign
2782 LOC: Config.ssl_client.cert_sign
2785 sslproxy_cert_sign <signing algorithm> acl ...
2787 The following certificate signing algorithms are supported:
2790 Sign using the configured CA certificate which is usually
2791 placed in and trusted by end-user browsers. This is the
2792 default for trusted origin server certificates.
2795 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2796 This is the default for untrusted origin server certificates
2797 that are not self-signed (see ssl::certUntrusted).
2800 Sign using a self-signed certificate with the right CN to
2801 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2802 browser. This is the default for self-signed origin server
2803 certificates (see ssl::certSelfSigned).
2805 This clause only supports fast acl types.
2807 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2808 signing algorithm to generate the certificate and ignores all
2809 subsequent sslproxy_cert_sign options (the first match wins). If no
2810 acl(s) match, the default signing algorithm is determined by errors
2811 detected when obtaining and validating the origin server certificate.
2813 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2814 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2815 CONNECT request that carries a domain name. In all other cases (CONNECT
2816 to an IP address or an intercepted SSL connection), Squid cannot detect
2817 the domain mismatch at certificate generation time when
2818 bump-server-first is used.
2821 NAME: sslproxy_cert_adapt
2824 TYPE: sslproxy_cert_adapt
2825 LOC: Config.ssl_client.cert_adapt
2828 sslproxy_cert_adapt <adaptation algorithm> acl ...
2830 The following certificate adaptation algorithms are supported:
2833 Sets the "Not After" property to the "Not After" property of
2834 the CA certificate used to sign generated certificates.
2837 Sets the "Not Before" property to the "Not Before" property of
2838 the CA certificate used to sign generated certificates.
2840 setCommonName or setCommonName{CN}
2841 Sets Subject.CN property to the host name specified as a
2842 CN parameter or, if no explicit CN parameter was specified,
2843 extracted from the CONNECT request. It is a misconfiguration
2844 to use setCommonName without an explicit parameter for
2845 intercepted or tproxied SSL connections.
2847 This clause only supports fast acl types.
2849 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2850 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2851 corresponding adaptation algorithm to generate the certificate and
2852 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2853 group (i.e., the first match wins within each algorithm group). If no
2854 acl(s) match, the default mimicking action takes place.
2856 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2857 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2858 CONNECT request that carries a domain name. In all other cases (CONNECT
2859 to an IP address or an intercepted SSL connection), Squid cannot detect
2860 the domain mismatch at certificate generation time when
2861 bump-server-first is used.
2864 NAME: sslpassword_program
2867 LOC: Config.Program.ssl_password
2870 Specify a program used for entering SSL key passphrases
2871 when using encrypted SSL certificate keys. If not specified
2872 keys must either be unencrypted, or Squid started with the -N
2873 option to allow it to query interactively for the passphrase.
2875 The key file name is given as argument to the program allowing
2876 selection of the right password if you have multiple encrypted
2881 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2882 -----------------------------------------------------------------------------
2885 NAME: sslcrtd_program
2888 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2889 LOC: Ssl::TheConfig.ssl_crtd
2891 Specify the location and options of the executable for ssl_crtd process.
2892 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2893 For more information use:
2894 @DEFAULT_SSL_CRTD@ -h
2897 NAME: sslcrtd_children
2898 TYPE: HelperChildConfig
2900 DEFAULT: 32 startup=5 idle=1
2901 LOC: Ssl::TheConfig.ssl_crtdChildren
2903 The maximum number of processes spawn to service ssl server.
2904 The maximum this may be safely set to is 32.
2906 The startup= and idle= options allow some measure of skew in your
2911 Sets the minimum number of processes to spawn when Squid
2912 starts or reconfigures. When set to zero the first request will
2913 cause spawning of the first child process to handle it.
2915 Starting too few children temporary slows Squid under load while it
2916 tries to spawn enough additional processes to cope with traffic.
2920 Sets a minimum of how many processes Squid is to try and keep available
2921 at all times. When traffic begins to rise above what the existing
2922 processes can handle this many more will be spawned up to the maximum
2923 configured. A minimum setting of 1 is required.
2927 Sets the maximum number of queued requests.
2928 If the queued requests exceed queue size for more than 3 minutes
2929 squid aborts its operation.
2930 The default value is set to 2*numberofchildren.
2932 You must have at least one ssl_crtd process.
2935 NAME: sslcrtvalidator_program
2939 LOC: Ssl::TheConfig.ssl_crt_validator
2941 Specify the location and options of the executable for ssl_crt_validator
2944 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
2947 ttl=n TTL in seconds for cached results. The default is 60 secs
2948 cache=n limit the result cache size. The default value is 2048
2951 NAME: sslcrtvalidator_children
2952 TYPE: HelperChildConfig
2954 DEFAULT: 32 startup=5 idle=1 concurrency=1
2955 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2957 The maximum number of processes spawn to service SSL server.
2958 The maximum this may be safely set to is 32.
2960 The startup= and idle= options allow some measure of skew in your
2965 Sets the minimum number of processes to spawn when Squid
2966 starts or reconfigures. When set to zero the first request will
2967 cause spawning of the first child process to handle it.
2969 Starting too few children temporary slows Squid under load while it
2970 tries to spawn enough additional processes to cope with traffic.
2974 Sets a minimum of how many processes Squid is to try and keep available
2975 at all times. When traffic begins to rise above what the existing
2976 processes can handle this many more will be spawned up to the maximum
2977 configured. A minimum setting of 1 is required.
2981 The number of requests each certificate validator helper can handle in
2982 parallel. A value of 0 indicates the certficate validator does not
2983 support concurrency. Defaults to 1.
2985 When this directive is set to a value >= 1 then the protocol
2986 used to communicate with the helper is modified to include
2987 a request ID in front of the request/response. The request
2988 ID from the request must be echoed back with the response
2993 Sets the maximum number of queued requests.
2994 If the queued requests exceed queue size for more than 3 minutes
2995 squid aborts its operation.
2996 The default value is set to 2*numberofchildren.
2998 You must have at least one ssl_crt_validator process.
3002 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
3003 -----------------------------------------------------------------------------
3011 To specify other caches in a hierarchy, use the format:
3013 cache_peer hostname type http-port icp-port [options]
3018 # hostname type port port options
3019 # -------------------- -------- ----- ----- -----------
3020 cache_peer parent.foo.net parent 3128 3130 default
3021 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
3022 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
3023 cache_peer example.com parent 80 0 default
3024 cache_peer cdn.example.com sibling 3128 0
3026 type: either 'parent', 'sibling', or 'multicast'.
3028 proxy-port: The port number where the peer accept HTTP requests.
3029 For other Squid proxies this is usually 3128
3030 For web servers this is usually 80
3032 icp-port: Used for querying neighbor caches about objects.
3033 Set to 0 if the peer does not support ICP or HTCP.
3034 See ICP and HTCP options below for additional details.
3037 ==== ICP OPTIONS ====
3039 You MUST also set icp_port and icp_access explicitly when using these options.
3040 The defaults will prevent peer traffic using ICP.
3043 no-query Disable ICP queries to this neighbor.
3046 Indicates the named peer is a member of a multicast group.
3047 ICP queries will not be sent directly to the peer, but ICP
3048 replies will be accepted from it.
3050 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
3051 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
3054 To only send ICP queries to this neighbor infrequently.
3055 This is used to keep the neighbor round trip time updated
3056 and is usually used in conjunction with weighted-round-robin.
3059 ==== HTCP OPTIONS ====
3061 You MUST also set htcp_port and htcp_access explicitly when using these options.
3062 The defaults will prevent peer traffic using HTCP.
3065 htcp Send HTCP, instead of ICP, queries to the neighbor.
3066 You probably also want to set the "icp-port" to 4827
3067 instead of 3130. This directive accepts a comma separated
3068 list of options described below.
3070 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
3072 htcp=no-clr Send HTCP to the neighbor but without
3073 sending any CLR requests. This cannot be used with
3076 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
3077 This cannot be used with no-clr.
3080 Send HTCP to the neighbor including CLRs but only when
3081 they do not result from PURGE requests.
3084 Forward any HTCP CLR requests this proxy receives to the peer.
3087 ==== PEER SELECTION METHODS ====
3089 The default peer selection method is ICP, with the first responding peer
3090 being used as source. These options can be used for better load balancing.
3093 default This is a parent cache which can be used as a "last-resort"
3094 if a peer cannot be located by any of the peer-selection methods.
3095 If specified more than once, only the first is used.
3097 round-robin Load-Balance parents which should be used in a round-robin
3098 fashion in the absence of any ICP queries.
3099 weight=N can be used to add bias.
3101 weighted-round-robin
3102 Load-Balance parents which should be used in a round-robin
3103 fashion with the frequency of each parent being based on the
3104 round trip time. Closer parents are used more often.
3105 Usually used for background-ping parents.
3106 weight=N can be used to add bias.
3108 carp Load-Balance parents which should be used as a CARP array.
3109 The requests will be distributed among the parents based on the
3110 CARP load balancing hash function based on their weight.
3112 userhash Load-balance parents based on the client proxy_auth or ident username.
3114 sourcehash Load-balance parents based on the client source IP.
3117 To be used only for cache peers of type "multicast".
3118 ALL members of this multicast group have "sibling"
3119 relationship with it, not "parent". This is to a multicast
3120 group when the requested object would be fetched only from
3121 a "parent" cache, anyway. It's useful, e.g., when
3122 configuring a pool of redundant Squid proxies, being
3123 members of the same multicast group.
3126 ==== PEER SELECTION OPTIONS ====
3128 weight=N use to affect the selection of a peer during any weighted
3129 peer-selection mechanisms.
3130 The weight must be an integer; default is 1,
3131 larger weights are favored more.
3132 This option does not affect parent selection if a peering
3133 protocol is not in use.
3135 basetime=N Specify a base amount to be subtracted from round trip
3137 It is subtracted before division by weight in calculating
3138 which parent to fectch from. If the rtt is less than the
3139 base time the rtt is set to a minimal value.
3141 ttl=N Specify a TTL to use when sending multicast ICP queries
3143 Only useful when sending to a multicast group.
3144 Because we don't accept ICP replies from random
3145 hosts, you must configure other group members as
3146 peers with the 'multicast-responder' option.
3148 no-delay To prevent access to this neighbor from influencing the
3151 digest-url=URL Tell Squid to fetch the cache digest (if digests are
3152 enabled) for this host from the specified URL rather
3153 than the Squid default location.
3156 ==== CARP OPTIONS ====
3158 carp-key=key-specification
3159 use a different key than the full URL to hash against the peer.
3160 the key-specification is a comma-separated list of the keywords
3161 scheme, host, port, path, params
3162 Order is not important.
3164 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
3166 originserver Causes this parent to be contacted as an origin server.
3167 Meant to be used in accelerator setups when the peer
3171 Set the Host header of requests forwarded to this peer.
3172 Useful in accelerator setups where the server (peer)
3173 expects a certain domain name but clients may request
3174 others. ie example.com or www.example.com
3176 no-digest Disable request of cache digests.
3179 Disables requesting ICMP RTT database (NetDB).
3182 ==== AUTHENTICATION OPTIONS ====
3185 If this is a personal/workgroup proxy and your parent
3186 requires proxy authentication.
3188 Note: The string can include URL escapes (i.e. %20 for
3189 spaces). This also means % must be written as %%.
3192 Send login details received from client to this peer.
3193 Both Proxy- and WWW-Authorization headers are passed
3194 without alteration to the peer.
3195 Authentication is not required by Squid for this to work.
3197 Note: This will pass any form of authentication but
3198 only Basic auth will work through a proxy unless the
3199 connection-auth options are also used.
3201 login=PASS Send login details received from client to this peer.
3202 Authentication is not required by this option.
3204 If there are no client-provided authentication headers
3205 to pass on, but username and password are available
3206 from an external ACL user= and password= result tags
3207 they may be sent instead.
3209 Note: To combine this with proxy_auth both proxies must
3210 share the same user database as HTTP only allows for
3211 a single login (one for proxy, one for origin server).
3212 Also be warned this will expose your users proxy
3213 password to the peer. USE WITH CAUTION
3216 Send the username to the upstream cache, but with a
3217 fixed password. This is meant to be used when the peer
3218 is in another administrative domain, but it is still
3219 needed to identify each user.
3220 The star can optionally be followed by some extra
3221 information which is added to the username. This can
3222 be used to identify this proxy to the peer, similar to
3223 the login=username:password option above.
3226 If this is a personal/workgroup proxy and your parent
3227 requires a secure proxy authentication.
3228 The first principal from the default keytab or defined by
3229 the environment variable KRB5_KTNAME will be used.
3231 WARNING: The connection may transmit requests from multiple
3232 clients. Negotiate often assumes end-to-end authentication
3233 and a single-client. Which is not strictly true here.
3235 login=NEGOTIATE:principal_name
3236 If this is a personal/workgroup proxy and your parent
3237 requires a secure proxy authentication.
3238 The principal principal_name from the default keytab or
3239 defined by the environment variable KRB5_KTNAME will be
3242 WARNING: The connection may transmit requests from multiple
3243 clients. Negotiate often assumes end-to-end authentication
3244 and a single-client. Which is not strictly true here.
3246 connection-auth=on|off
3247 Tell Squid that this peer does or not support Microsoft
3248 connection oriented authentication, and any such
3249 challenges received from there should be ignored.
3250 Default is auto to automatically determine the status
3254 ==== SSL / HTTPS / TLS OPTIONS ====
3256 ssl Encrypt connections to this peer with SSL/TLS.
3258 sslcert=/path/to/ssl/certificate
3259 A client SSL certificate to use when connecting to
3262 sslkey=/path/to/ssl/key
3263 The private SSL key corresponding to sslcert above.
3264 If 'sslkey' is not specified 'sslcert' is assumed to
3265 reference a combined file containing both the
3266 certificate and the key.
3268 sslversion=1|3|4|5|6
3269 The SSL version to use when connecting to this peer
3270 1 = automatic (default)
3276 sslcipher=... The list of valid SSL ciphers to use when connecting
3279 ssloptions=... Specify various SSL implementation options:
3281 NO_SSLv3 Disallow the use of SSLv3
3283 NO_TLSv1 Disallow the use of TLSv1.0
3285 NO_TLSv1_1 Disallow the use of TLSv1.1
3287 NO_TLSv1_2 Disallow the use of TLSv1.2
3290 Always create a new key when using
3291 temporary/ephemeral DH key exchanges
3294 Disable use of RFC5077 session tickets.
3295 Some servers may have problems
3296 understanding the TLS extension due
3297 to ambiguous specification in RFC4507.
3299 ALL Enable various bug workarounds
3300 suggested as "harmless" by OpenSSL
3301 Be warned that this reduces SSL/TLS
3302 strength to some attacks.
3304 See the OpenSSL SSL_CTX_set_options documentation for a
3307 sslcafile=... A file containing additional CA certificates to use
3308 when verifying the peer certificate.
3310 sslcapath=... A directory containing additional CA certificates to
3311 use when verifying the peer certificate.
3313 sslcrlfile=... A certificate revocation list file to use when
3314 verifying the peer certificate.
3316 sslflags=... Specify various flags modifying the SSL implementation:
3319 Accept certificates even if they fail to
3323 Don't use the default CA list built in
3327 Don't verify the peer certificate
3328 matches the server name
3330 ssldomain= The peer name as advertised in it's certificate.
3331 Used for verifying the correctness of the received peer
3332 certificate. If not specified the peer hostname will be
3336 Enable the "Front-End-Https: On" header needed when
3337 using Squid as a SSL frontend in front of Microsoft OWA.
3338 See MS KB document Q307347 for details on this header.
3339 If set to auto the header will only be added if the
3340 request is forwarded as a https:// URL.
3343 ==== GENERAL OPTIONS ====
3346 A peer-specific connect timeout.
3347 Also see the peer_connect_timeout directive.
3349 connect-fail-limit=N
3350 How many times connecting to a peer must fail before
3351 it is marked as down. Standby connection failures
3352 count towards this limit. Default is 10.
3354 allow-miss Disable Squid's use of only-if-cached when forwarding
3355 requests to siblings. This is primarily useful when
3356 icp_hit_stale is used by the sibling. To extensive use
3357 of this option may result in forwarding loops, and you
3358 should avoid having two-way peerings with this option.
3359 For example to deny peer usage on requests from peer
3360 by denying cache_peer_access if the source is a peer.
3362 max-conn=N Limit the number of concurrent connections the Squid
3363 may open to this peer, including already opened idle
3364 and standby connections. There is no peer-specific
3365 connection limit by default.
3367 A peer exceeding the limit is not used for new
3368 requests unless a standby connection is available.
3370 max-conn currently works poorly with idle persistent
3371 connections: When a peer reaches its max-conn limit,
3372 and there are idle persistent connections to the peer,
3373 the peer may not be selected because the limiting code
3374 does not know whether Squid can reuse those idle
3377 standby=N Maintain a pool of N "hot standby" connections to an
3378 UP peer, available for requests when no idle
3379 persistent connection is available (or safe) to use.
3380 By default and with zero N, no such pool is maintained.
3381 N must not exceed the max-conn limit (if any).
3383 At start or after reconfiguration, Squid opens new TCP
3384 standby connections until there are N connections
3385 available and then replenishes the standby pool as
3386 opened connections are used up for requests. A used
3387 connection never goes back to the standby pool, but
3388 may go to the regular idle persistent connection pool
3389 shared by all peers and origin servers.
3391 Squid never opens multiple new standby connections
3392 concurrently. This one-at-a-time approach minimizes
3393 flooding-like effect on peers. Furthermore, just a few
3394 standby connections should be sufficient in most cases
3395 to supply most new requests with a ready-to-use
3398 Standby connections obey server_idle_pconn_timeout.
3399 For the feature to work as intended, the peer must be
3400 configured to accept and keep them open longer than
3401 the idle timeout at the connecting Squid, to minimize
3402 race conditions typical to idle used persistent
3403 connections. Default request_timeout and
3404 server_idle_pconn_timeout values ensure such a
3407 name=xxx Unique name for the peer.
3408 Required if you have multiple peers on the same host
3409 but different ports.
3410 This name can be used in cache_peer_access and similar
3411 directives to dentify the peer.
3412 Can be used by outgoing access controls through the
3415 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3416 requests to this peer. Use normal address selection instead.
3417 This overrides the spoof_client_ip ACL.
3419 proxy-only objects fetched from the peer will not be stored locally.
3423 NAME: cache_peer_access
3428 Use to limit the requests for which a neighbor proxy will be
3429 queried. Peers with no restrictions are queried for all requests.
3432 cache_peer_access cache-host allow|deny [!]aclname ...
3434 The syntax is identical to 'http_access' and the other lists of
3435 ACL elements. See the comments for 'http_access', or the
3436 Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
3439 NAME: neighbor_type_domain
3440 TYPE: hostdomaintype
3442 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3445 Modify the cache_peer neighbor type when passing requests
3446 about specific domains to the peer.
3449 neighbor_type_domain neighbor parent|sibling domain domain ...
3452 cache_peer foo.example.com parent 3128 3130
3453 neighbor_type_domain foo.example.com sibling .au .de
3455 The above configuration treats all requests to foo.example.com as a
3456 parent proxy unless the request is for a .au or .de ccTLD domain name.
3459 NAME: dead_peer_timeout
3463 LOC: Config.Timeout.deadPeer
3465 This controls how long Squid waits to declare a peer cache
3466 as "dead." If there are no ICP replies received in this
3467 amount of time, Squid will declare the peer dead and not
3468 expect to receive any further ICP replies. However, it
3469 continues to send ICP queries, and will mark the peer as
3470 alive upon receipt of the first subsequent ICP reply.
3472 This timeout also affects when Squid expects to receive ICP
3473 replies from peers. If more than 'dead_peer' seconds have
3474 passed since the last ICP reply was received, Squid will not
3475 expect to receive an ICP reply on the next query. Thus, if
3476 your time between requests is greater than this timeout, you
3477 will see a lot of requests sent DIRECT to origin servers
3478 instead of to your parents.
3481 NAME: forward_max_tries
3484 LOC: Config.forward_max_tries
3486 Controls how many different forward paths Squid will try
3487 before giving up. See also forward_timeout.
3489 NOTE: connect_retries (default: none) can make each of these
3490 possible forwarding paths be tried multiple times.
3494 MEMORY CACHE OPTIONS
3495 -----------------------------------------------------------------------------
3502 LOC: Config.memMaxSize
3504 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3505 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3506 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3507 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3509 'cache_mem' specifies the ideal amount of memory to be used
3511 * In-Transit objects
3513 * Negative-Cached objects
3515 Data for these objects are stored in 4 KB blocks. This
3516 parameter specifies the ideal upper limit on the total size of
3517 4 KB blocks allocated. In-Transit objects take the highest
3520 In-transit objects have priority over the others. When
3521 additional space is needed for incoming data, negative-cached
3522 and hot objects will be released. In other words, the
3523 negative-cached and hot objects will fill up any unused space
3524 not needed for in-transit objects.
3526 If circumstances require, this limit will be exceeded.
3527 Specifically, if your incoming request rate requires more than
3528 'cache_mem' of memory to hold in-transit objects, Squid will
3529 exceed this limit to satisfy the new requests. When the load
3530 decreases, blocks will be freed until the high-water mark is
3531 reached. Thereafter, blocks will be used to store hot
3534 If shared memory caching is enabled, Squid does not use the shared
3535 cache space for in-transit objects, but they still consume as much
3536 local memory as they need. For more details about the shared memory
3537 cache, see memory_cache_shared.
3540 NAME: maximum_object_size_in_memory
3544 LOC: Config.Store.maxInMemObjSize
3546 Objects greater than this size will not be attempted to kept in
3547 the memory cache. This should be set high enough to keep objects
3548 accessed frequently in memory to improve performance whilst low
3549 enough to keep larger objects from hoarding cache_mem.
3552 NAME: memory_cache_shared
3555 LOC: Config.memShared
3557 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3559 Controls whether the memory cache is shared among SMP workers.
3561 The shared memory cache is meant to occupy cache_mem bytes and replace
3562 the non-shared memory cache, although some entities may still be
3563 cached locally by workers for now (e.g., internal and in-transit
3564 objects may be served from a local memory cache even if shared memory
3565 caching is enabled).
3567 By default, the memory cache is shared if and only if all of the
3568 following conditions are satisfied: Squid runs in SMP mode with
3569 multiple workers, cache_mem is positive, and Squid environment
3570 supports required IPC primitives (e.g., POSIX shared memory segments
3571 and GCC-style atomic operations).
3573 To avoid blocking locks, shared memory uses opportunistic algorithms
3574 that do not guarantee that every cachable entity that could have been
3575 shared among SMP workers will actually be shared.
3577 Currently, entities exceeding 32KB in size cannot be shared.
3580 NAME: memory_cache_mode
3584 DEFAULT_DOC: Keep the most recently fetched objects in memory
3586 Controls which objects to keep in the memory cache (cache_mem)
3588 always Keep most recently fetched objects in memory (default)
3590 disk Only disk cache hits are kept in memory, which means
3591 an object must first be cached on disk and then hit
3592 a second time before cached in memory.
3594 network Only objects fetched from network is kept in memory
3597 NAME: memory_replacement_policy
3599 LOC: Config.memPolicy
3602 The memory replacement policy parameter determines which
3603 objects are purged from memory when memory space is needed.
3605 See cache_replacement_policy for details on algorithms.
3610 -----------------------------------------------------------------------------
3613 NAME: cache_replacement_policy
3615 LOC: Config.replPolicy
3618 The cache replacement policy parameter determines which
3619 objects are evicted (replaced) when disk space is needed.
3621 lru : Squid's original list based LRU policy
3622 heap GDSF : Greedy-Dual Size Frequency
3623 heap LFUDA: Least Frequently Used with Dynamic Aging
3624 heap LRU : LRU policy implemented using a heap
3626 Applies to any cache_dir lines listed below this directive.
3628 The LRU policies keeps recently referenced objects.
3630 The heap GDSF policy optimizes object hit rate by keeping smaller
3631 popular objects in cache so it has a better chance of getting a
3632 hit. It achieves a lower byte hit rate than LFUDA though since
3633 it evicts larger (possibly popular) objects.
3635 The heap LFUDA policy keeps popular objects in cache regardless of
3636 their size and thus optimizes byte hit rate at the expense of
3637 hit rate since one large, popular object will prevent many
3638 smaller, slightly less popular objects from being cached.
3640 Both policies utilize a dynamic aging mechanism that prevents
3641 cache pollution that can otherwise occur with frequency-based
3642 replacement policies.
3644 NOTE: if using the LFUDA replacement policy you should increase
3645 the value of maximum_object_size above its default of 4 MB to
3646 to maximize the potential byte hit rate improvement of LFUDA.
3648 For more information about the GDSF and LFUDA cache replacement
3649 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3650 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3653 NAME: minimum_object_size
3657 DEFAULT_DOC: no limit
3658 LOC: Config.Store.minObjectSize
3660 Objects smaller than this size will NOT be saved on disk. The
3661 value is specified in bytes, and the default is 0 KB, which
3662 means all responses can be stored.
3665 NAME: maximum_object_size
3669 LOC: Config.Store.maxObjectSize
3671 Set the default value for max-size parameter on any cache_dir.
3672 The value is specified in bytes, and the default is 4 MB.
3674 If you wish to get a high BYTES hit ratio, you should probably
3675 increase this (one 32 MB object hit counts for 3200 10KB
3678 If you wish to increase hit ratio more than you want to
3679 save bandwidth you should leave this low.
3681 NOTE: if using the LFUDA replacement policy you should increase
3682 this value to maximize the byte hit rate improvement of LFUDA!
3683 See cache_replacement_policy for a discussion of this policy.
3689 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3690 LOC: Config.cacheSwap
3693 cache_dir Type Directory-Name Fs-specific-data [options]
3695 You can specify multiple cache_dir lines to spread the
3696 cache among different disk partitions.
3698 Type specifies the kind of storage system to use. Only "ufs"
3699 is built by default. To enable any of the other storage systems
3700 see the --enable-storeio configure option.
3702 'Directory' is a top-level directory where cache swap
3703 files will be stored. If you want to use an entire disk
3704 for caching, this can be the mount-point directory.
3705 The directory must exist and be writable by the Squid
3706 process. Squid will NOT create this directory for you.
3708 In SMP configurations, cache_dir must not precede the workers option
3709 and should use configuration macros or conditionals to give each
3710 worker interested in disk caching a dedicated cache directory.
3713 ==== The ufs store type ====
3715 "ufs" is the old well-known Squid storage format that has always
3719 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3721 'Mbytes' is the amount of disk space (MB) to use under this
3722 directory. The default is 100 MB. Change this to suit your
3723 configuration. Do NOT put the size of your disk drive here.
3724 Instead, if you want Squid to use the entire disk drive,
3725 subtract 20% and use that value.
3727 'L1' is the number of first-level subdirectories which
3728 will be created under the 'Directory'. The default is 16.
3730 'L2' is the number of second-level subdirectories which
3731 will be created under each first-level directory. The default
3735 ==== The aufs store type ====
3737 "aufs" uses the same storage format as "ufs", utilizing
3738 POSIX-threads to avoid blocking the main Squid process on
3739 disk-I/O. This was formerly known in Squid as async-io.
3742 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3744 see argument descriptions under ufs above
3747 ==== The diskd store type ====
3749 "diskd" uses the same storage format as "ufs", utilizing a
3750 separate process to avoid blocking the main Squid process on
3754 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3756 see argument descriptions under ufs above
3758 Q1 specifies the number of unacknowledged I/O requests when Squid
3759 stops opening new files. If this many messages are in the queues,
3760 Squid won't open new files. Default is 64
3762 Q2 specifies the number of unacknowledged messages when Squid
3763 starts blocking. If this many messages are in the queues,
3764 Squid blocks until it receives some replies. Default is 72
3766 When Q1 < Q2 (the default), the cache directory is optimized
3767 for lower response time at the expense of a decrease in hit
3768 ratio. If Q1 > Q2, the cache directory is optimized for
3769 higher hit ratio at the expense of an increase in response
3773 ==== The rock store type ====
3776 cache_dir rock Directory-Name Mbytes [options]
3778 The Rock Store type is a database-style storage. All cached
3779 entries are stored in a "database" file, using fixed-size slots.
3780 A single entry occupies one or more slots.
3782 If possible, Squid using Rock Store creates a dedicated kid
3783 process called "disker" to avoid blocking Squid worker(s) on disk
3784 I/O. One disker kid is created for each rock cache_dir. Diskers
3785 are created only when Squid, running in daemon mode, has support
3786 for the IpcIo disk I/O module.
3788 swap-timeout=msec: Squid will not start writing a miss to or
3789 reading a hit from disk if it estimates that the swap operation
3790 will take more than the specified number of milliseconds. By
3791 default and when set to zero, disables the disk I/O time limit
3792 enforcement. Ignored when using blocking I/O module because
3793 blocking synchronous I/O does not allow Squid to estimate the
3794 expected swap wait time.
3796 max-swap-rate=swaps/sec: Artificially limits disk access using
3797 the specified I/O rate limit. Swap out requests that
3798 would cause the average I/O rate to exceed the limit are
3799 delayed. Individual swap in requests (i.e., hits or reads) are
3800 not delayed, but they do contribute to measured swap rate and
3801 since they are placed in the same FIFO queue as swap out
3802 requests, they may wait longer if max-swap-rate is smaller.
3803 This is necessary on file systems that buffer "too
3804 many" writes and then start blocking Squid and other processes
3805 while committing those writes to disk. Usually used together
3806 with swap-timeout to avoid excessive delays and queue overflows
3807 when disk demand exceeds available disk "bandwidth". By default
3808 and when set to zero, disables the disk I/O rate limit
3809 enforcement. Currently supported by IpcIo module only.
3811 slot-size=bytes: The size of a database "record" used for
3812 storing cached responses. A cached response occupies at least
3813 one slot and all database I/O is done using individual slots so
3814 increasing this parameter leads to more disk space waste while
3815 decreasing it leads to more disk I/O overheads. Should be a
3816 multiple of your operating system I/O page size. Defaults to
3817 16KBytes. A housekeeping header is stored with each slot and
3818 smaller slot-sizes will be rejected. The header is smaller than
3822 ==== COMMON OPTIONS ====
3824 no-store no new objects should be stored to this cache_dir.
3826 min-size=n the minimum object size in bytes this cache_dir
3827 will accept. It's used to restrict a cache_dir
3828 to only store large objects (e.g. AUFS) while
3829 other stores are optimized for smaller objects
3833 max-size=n the maximum object size in bytes this cache_dir
3835 The value in maximum_object_size directive sets
3836 the default unless more specific details are
3837 available (ie a small store capacity).
3839 Note: To make optimal use of the max-size limits you should order
3840 the cache_dir lines with the smallest max-size value first.
3844 # Uncomment and adjust the following to add a disk cache directory.
3845 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3849 NAME: store_dir_select_algorithm
3851 LOC: Config.store_dir_select_algorithm
3854 How Squid selects which cache_dir to use when the response
3855 object will fit into more than one.
3857 Regardless of which algorithm is used the cache_dir min-size
3858 and max-size parameters are obeyed. As such they can affect
3859 the selection algorithm by limiting the set of considered
3866 This algorithm is suited to caches with similar cache_dir
3867 sizes and disk speeds.
3869 The disk with the least I/O pending is selected.
3870 When there are multiple disks with the same I/O load ranking
3871 the cache_dir with most available capacity is selected.
3873 When a mix of cache_dir sizes are configured the faster disks
3874 have a naturally lower I/O loading and larger disks have more
3875 capacity. So space used to store objects and data throughput
3876 may be very unbalanced towards larger disks.
3881 This algorithm is suited to caches with unequal cache_dir
3884 Each cache_dir is selected in a rotation. The next suitable
3887 Available cache_dir capacity is only considered in relation
3888 to whether the object will fit and meets the min-size and
3889 max-size parameters.
3891 Disk I/O loading is only considered to prevent overload on slow
3892 disks. This algorithm does not spread objects by size, so any
3893 I/O loading per-disk may appear very unbalanced and volatile.
3895 If several cache_dirs use similar min-size, max-size, or other
3896 limits to to reject certain responses, then do not group such
3897 cache_dir lines together, to avoid round-robin selection bias
3898 towards the first cache_dir after the group. Instead, interleave
3899 cache_dir lines from different groups. For example:
3901 store_dir_select_algorithm round-robin
3902 cache_dir rock /hdd1 ... min-size=100000
3903 cache_dir rock /ssd1 ... max-size=99999
3904 cache_dir rock /hdd2 ... min-size=100000
3905 cache_dir rock /ssd2 ... max-size=99999
3906 cache_dir rock /hdd3 ... min-size=100000
3907 cache_dir rock /ssd3 ... max-size=99999
3910 NAME: max_open_disk_fds
3912 LOC: Config.max_open_disk_fds
3914 DEFAULT_DOC: no limit
3916 To avoid having disk as the I/O bottleneck Squid can optionally
3917 bypass the on-disk cache if more than this amount of disk file
3918 descriptors are open.
3920 A value of 0 indicates no limit.
3923 NAME: cache_swap_low
3924 COMMENT: (percent, 0-100)
3927 LOC: Config.Swap.lowWaterMark
3929 The low-water mark for cache object replacement.
3930 Replacement begins when the swap (disk) usage is above the
3931 low-water mark and attempts to maintain utilization near the
3932 low-water mark. As swap utilization gets close to high-water
3933 mark object eviction becomes more aggressive. If utilization is
3934 close to the low-water mark less replacement is done each time.
3936 Defaults are 90% and 95%. If you have a large cache, 5% could be
3937 hundreds of MB. If this is the case you may wish to set these
3938 numbers closer together.
3940 See also cache_swap_high
3943 NAME: cache_swap_high
3944 COMMENT: (percent, 0-100)
3947 LOC: Config.Swap.highWaterMark
3949 The high-water mark for cache object replacement.
3950 Replacement begins when the swap (disk) usage is above the
3951 low-water mark and attempts to maintain utilization near the
3952 low-water mark. As swap utilization gets close to high-water
3953 mark object eviction becomes more aggressive. If utilization is
3954 close to the low-water mark less replacement is done each time.
3956 Defaults are 90% and 95%. If you have a large cache, 5% could be
3957 hundreds of MB. If this is the case you may wish to set these
3958 numbers closer together.
3960 See also cache_swap_low
3965 -----------------------------------------------------------------------------
3972 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
3976 logformat <name> <format specification>
3978 Defines an access log format.
3980 The <format specification> is a string with embedded % format codes
3982 % format codes all follow the same basic structure where all but
3983 the formatcode is optional. Output strings are automatically escaped
3984 as required according to their context and the output format
3985 modifiers are usually not needed, but can be specified if an explicit
3986 output format is desired.
3988 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3990 " output in quoted string format
3991 [ output in squid text log format as used by log_mime_hdrs
3992 # output in URL quoted format
3997 width minimum and/or maximum field width:
3998 [width_min][.width_max]
3999 When minimum starts with 0, the field is zero-padded.
4000 String values exceeding maximum width are truncated.
4002 {arg} argument such as header name etc
4006 % a literal % character
4007 sn Unique sequence number per log line entry
4008 err_code The ID of an error response served by Squid or
4009 a similar internal error identifier.
4010 err_detail Additional err_code-dependent error information.
4011 note The annotation specified by the argument. Also
4012 logs the adaptation meta headers set by the
4013 adaptation_meta configuration parameter.
4014 If no argument given all annotations logged.
4015 The argument may include a separator to use with
4018 By default, multiple note values are separated with ","
4019 and multiple notes are separated with "\r\n".
4020 When logging named notes with %{name}note, the
4021 explicitly configured separator is used between note
4022 values. When logging all notes with %note, the
4023 explicitly configured separator is used between
4024 individual notes. There is currently no way to
4025 specify both value and notes separators when logging
4026 all notes with %note.
4028 Connection related format codes:
4030 >a Client source IP address
4032 >p Client source port
4033 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
4034 >la Local IP address the client connected to
4035 >lp Local port number the client connected to
4036 >qos Client connection TOS/DSCP value set by Squid
4037 >nfmark Client connection netfilter mark set by Squid
4039 la Local listening IP address the client connection was connected to.
4040 lp Local listening port number the client connection was connected to.
4042 <a Server IP address of the last server or peer connection
4043 <A Server FQDN or peer name
4044 <p Server port number of the last server or peer connection
4045 <la Local IP address of the last server or peer connection
4046 <lp Local port number of the last server or peer connection
4047 <qos Server connection TOS/DSCP value set by Squid
4048 <nfmark Server connection netfilter mark set by Squid
4050 Time related format codes:
4052 ts Seconds since epoch
4053 tu subsecond time (milliseconds)
4054 tl Local time. Optional strftime format argument
4055 default %d/%b/%Y:%H:%M:%S %z
4056 tg GMT time. Optional strftime format argument
4057 default %d/%b/%Y:%H:%M:%S %z
4058 tr Response time (milliseconds)
4059 dt Total time spent making DNS lookups (milliseconds)
4060 tS Approximate master transaction start time in
4061 <full seconds since epoch>.<fractional seconds> format.
4062 Currently, Squid considers the master transaction
4063 started when a complete HTTP request header initiating
4064 the transaction is received from the client. This is
4065 the same value that Squid uses to calculate transaction
4066 response time when logging %tr to access.log. Currently,
4067 Squid uses millisecond resolution for %tS values,
4068 similar to the default access.log "current time" field
4071 Access Control related format codes:
4073 et Tag returned by external acl
4074 ea Log string returned by external acl
4075 un User name (any available)
4076 ul User name from authentication
4077 ue User name from external acl helper
4078 ui User name from ident
4079 us User name from SSL
4080 credentials Client credentials. The exact meaning depends on
4081 the authentication scheme: For Basic authentication,
4082 it is the password; for Digest, the realm sent by the
4083 client; for NTLM and Negotiate, the client challenge
4084 or client credentials prefixed with "YR " or "KK ".
4086 HTTP related format codes:
4090 [http::]rm Request method (GET/POST etc)
4091 [http::]>rm Request method from client
4092 [http::]<rm Request method sent to server or peer
4093 [http::]ru Request URL from client (historic, filtered for logging)
4094 [http::]>ru Request URL from client
4095 [http::]<ru Request URL sent to server or peer
4096 [http::]>rs Request URL scheme from client
4097 [http::]<rs Request URL scheme sent to server or peer
4098 [http::]>rd Request URL domain from client
4099 [http::]<rd Request URL domain sent to server or peer
4100 [http::]>rP Request URL port from client
4101 [http::]<rP Request URL port sent to server or peer
4102 [http::]rp Request URL path excluding hostname
4103 [http::]>rp Request URL path excluding hostname from client
4104 [http::]<rp Request URL path excluding hostname sent to server or peer
4105 [http::]rv Request protocol version
4106 [http::]>rv Request protocol version from client
4107 [http::]<rv Request protocol version sent to server or peer
4109 [http::]>h Original received request header.
4110 Usually differs from the request header sent by
4111 Squid, although most fields are often preserved.
4112 Accepts optional header field name/value filter
4113 argument using name[:[separator]element] format.
4114 [http::]>ha Received request header after adaptation and
4115 redirection (pre-cache REQMOD vectoring point).
4116 Usually differs from the request header sent by
4117 Squid, although most fields are often preserved.
4118 Optional header name argument as for >h
4123 [http::]<Hs HTTP status code received from the next hop
4124 [http::]>Hs HTTP status code sent to the client
4126 [http::]<h Reply header. Optional header name argument
4129 [http::]mt MIME content type
4134 [http::]st Total size of request + reply traffic with client
4135 [http::]>st Total size of request received from client.
4136 Excluding chunked encoding bytes.
4137 [http::]<st Total size of reply sent to client (after adaptation)
4139 [http::]>sh Size of request headers received from client
4140 [http::]<sh Size of reply headers sent to client (after adaptation)
4142 [http::]<sH Reply high offset sent
4143 [http::]<sS Upstream object size
4145 [http::]<bs Number of HTTP-equivalent message body bytes
4146 received from the next hop, excluding chunked
4147 transfer encoding and control messages.
4148 Generated FTP/Gopher listings are treated as
4154 [http::]<pt Peer response time in milliseconds. The timer starts
4155 when the last request byte is sent to the next hop
4156 and stops when the last response byte is received.
4157 [http::]<tt Total time in milliseconds. The timer
4158 starts with the first connect request (or write I/O)
4159 sent to the first selected peer. The timer stops
4160 with the last I/O with the last peer.
4162 Squid handling related format codes:
4164 Ss Squid request status (TCP_MISS etc)
4165 Sh Squid hierarchy status (DEFAULT_PARENT etc)
4167 SSL-related format codes:
4169 ssl::bump_mode SslBump decision for the transaction:
4171 For CONNECT requests that initiated bumping of
4172 a connection and for any request received on
4173 an already bumped connection, Squid logs the
4174 corresponding SslBump mode ("server-first" or
4175 "client-first"). See the ssl_bump option for
4176 more information about these modes.
4178 A "none" token is logged for requests that
4179 triggered "ssl_bump" ACL evaluation matching
4180 either a "none" rule or no rules at all.
4182 In all other cases, a single dash ("-") is
4185 ssl::>sni SSL client SNI sent to Squid. Available only
4186 after the peek, stare, or splice SSL bumping
4189 If ICAP is enabled, the following code becomes available (as
4190 well as ICAP log codes documented with the icap_log option):
4192 icap::tt Total ICAP processing time for the HTTP
4193 transaction. The timer ticks when ICAP
4194 ACLs are checked and when ICAP
4195 transaction is in progress.
4197 If adaptation is enabled the following three codes become available:
4199 adapt::<last_h The header of the last ICAP response or
4200 meta-information from the last eCAP
4201 transaction related to the HTTP transaction.
4202 Like <h, accepts an optional header name
4205 adapt::sum_trs Summed adaptation transaction response
4206 times recorded as a comma-separated list in
4207 the order of transaction start time. Each time
4208 value is recorded as an integer number,
4209 representing response time of one or more
4210 adaptation (ICAP or eCAP) transaction in
4211 milliseconds. When a failed transaction is
4212 being retried or repeated, its time is not
4213 logged individually but added to the
4214 replacement (next) transaction. See also:
4217 adapt::all_trs All adaptation transaction response times.
4218 Same as adaptation_strs but response times of
4219 individual transactions are never added
4220 together. Instead, all transaction response
4221 times are recorded individually.
4223 You can prefix adapt::*_trs format codes with adaptation
4224 service name in curly braces to record response time(s) specific
4225 to that service. For example: %{my_service}adapt::sum_trs
4227 If SSL is enabled, the following formating codes become available:
4229 %ssl::>cert_subject The Subject field of the received client
4230 SSL certificate or a dash ('-') if Squid has
4231 received an invalid/malformed certificate or
4232 no certificate at all. Consider encoding the
4233 logged value because Subject often has spaces.
4235 %ssl::>cert_issuer The Issuer field of the received client
4236 SSL certificate or a dash ('-') if Squid has
4237 received an invalid/malformed certificate or
4238 no certificate at all. Consider encoding the
4239 logged value because Issuer often has spaces.
4241 The default formats available (which do not need re-defining) are:
4243 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
4244 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
4245 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
4246 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
4247 logformat useragent %>a [%tl] "%{User-Agent}>h"
4249 NOTE: When the log_mime_hdrs directive is set to ON.
4250 The squid, common and combined formats have a safely encoded copy
4251 of the mime headers appended to each line within a pair of brackets.
4253 NOTE: The common and combined formats are not quite true to the Apache definition.
4254 The logs from Squid contain an extra status and hierarchy code appended.
4258 NAME: access_log cache_access_log
4260 LOC: Config.Log.accesslogs
4261 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
4263 Configures whether and how Squid logs HTTP and ICP transactions.
4264 If access logging is enabled, a single line is logged for every
4265 matching HTTP or ICP request. The recommended directive formats are:
4267 access_log <module>:<place> [option ...] [acl acl ...]
4268 access_log none [acl acl ...]
4270 The following directive format is accepted but may be deprecated:
4271 access_log <module>:<place> [<logformat name> [acl acl ...]]
4273 In most cases, the first ACL name must not contain the '=' character
4274 and should not be equal to an existing logformat name. You can always
4275 start with an 'all' ACL to work around those restrictions.
4277 Will log to the specified module:place using the specified format (which
4278 must be defined in a logformat directive) those entries which match
4279 ALL the acl's specified (which must be defined in acl clauses).
4280 If no acl is specified, all requests will be logged to this destination.
4282 ===== Available options for the recommended directive format =====
4284 logformat=name Names log line format (either built-in or
4285 defined by a logformat directive). Defaults
4288 buffer-size=64KB Defines approximate buffering limit for log
4289 records (see buffered_logs). Squid should not
4290 keep more than the specified size and, hence,
4291 should flush records before the buffer becomes
4292 full to avoid overflows under normal
4293 conditions (the exact flushing algorithm is
4294 module-dependent though). The on-error option
4295 controls overflow handling.
4297 on-error=die|drop Defines action on unrecoverable errors. The
4298 'drop' action ignores (i.e., does not log)
4299 affected log records. The default 'die' action
4300 kills the affected worker. The drop action
4301 support has not been tested for modules other
4304 rotate=N Specifies the number of log file rotations to
4305 make when you run 'squid -k rotate'. The default
4306 is to obey the logfile_rotate directive. Setting
4307 rotate=0 will disable the file name rotation,
4308 but the log files are still closed and re-opened.
4309 This will enable you to rename the logfiles
4310 yourself just before sending the rotate signal.
4311 Only supported by the stdio module.
4313 ===== Modules Currently available =====
4315 none Do not log any requests matching these ACL.
4316 Do not specify Place or logformat name.
4318 stdio Write each log line to disk immediately at the completion of
4320 Place: the filename and path to be written.
4322 daemon Very similar to stdio. But instead of writing to disk the log
4323 line is passed to a daemon helper for asychronous handling instead.
4324 Place: varies depending on the daemon.
4326 log_file_daemon Place: the file name and path to be written.
4328 syslog To log each request via syslog facility.
4329 Place: The syslog facility and priority level for these entries.
4330 Place Format: facility.priority
4332 where facility could be any of:
4333 authpriv, daemon, local0 ... local7 or user.
4335 And priority could be any of:
4336 err, warning, notice, info, debug.
4338 udp To send each log line as text data to a UDP receiver.
4339 Place: The destination host name or IP and port.
4340 Place Format: //host:port
4342 tcp To send each log line as text data to a TCP receiver.
4343 Lines may be accumulated before sending (see buffered_logs).
4344 Place: The destination host name or IP and port.
4345 Place Format: //host:port
4348 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4354 LOC: Config.Log.icaplogs
4357 ICAP log files record ICAP transaction summaries, one line per
4360 The icap_log option format is:
4361 icap_log <filepath> [<logformat name> [acl acl ...]]
4362 icap_log none [acl acl ...]]
4364 Please see access_log option documentation for details. The two
4365 kinds of logs share the overall configuration approach and many
4368 ICAP processing of a single HTTP message or transaction may
4369 require multiple ICAP transactions. In such cases, multiple
4370 ICAP transaction log lines will correspond to a single access
4373 ICAP log uses logformat codes that make sense for an ICAP
4374 transaction. Header-related codes are applied to the HTTP header
4375 embedded in an ICAP server response, with the following caveats:
4376 For REQMOD, there is no HTTP response header unless the ICAP
4377 server performed request satisfaction. For RESPMOD, the HTTP
4378 request header is the header sent to the ICAP server. For
4379 OPTIONS, there are no HTTP headers.
4381 The following format codes are also available for ICAP logs:
4383 icap::<A ICAP server IP address. Similar to <A.
4385 icap::<service_name ICAP service name from the icap_service
4386 option in Squid configuration file.
4388 icap::ru ICAP Request-URI. Similar to ru.
4390 icap::rm ICAP request method (REQMOD, RESPMOD, or
4391 OPTIONS). Similar to existing rm.
4393 icap::>st Bytes sent to the ICAP server (TCP payload
4394 only; i.e., what Squid writes to the socket).
4396 icap::<st Bytes received from the ICAP server (TCP
4397 payload only; i.e., what Squid reads from
4400 icap::<bs Number of message body bytes received from the
4401 ICAP server. ICAP message body, if any, usually
4402 includes encapsulated HTTP message headers and
4403 possibly encapsulated HTTP message body. The
4404 HTTP body part is dechunked before its size is
4407 icap::tr Transaction response time (in
4408 milliseconds). The timer starts when
4409 the ICAP transaction is created and
4410 stops when the transaction is completed.
4413 icap::tio Transaction I/O time (in milliseconds). The
4414 timer starts when the first ICAP request
4415 byte is scheduled for sending. The timers
4416 stops when the last byte of the ICAP response
4419 icap::to Transaction outcome: ICAP_ERR* for all
4420 transaction errors, ICAP_OPT for OPTION
4421 transactions, ICAP_ECHO for 204
4422 responses, ICAP_MOD for message
4423 modification, and ICAP_SAT for request
4424 satisfaction. Similar to Ss.
4426 icap::Hs ICAP response status code. Similar to Hs.
4428 icap::>h ICAP request header(s). Similar to >h.
4430 icap::<h ICAP response header(s). Similar to <h.
4432 The default ICAP log format, which can be used without an explicit
4433 definition, is called icap_squid:
4435 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
4437 See also: logformat, log_icap, and %adapt::<last_h
4440 NAME: logfile_daemon
4442 DEFAULT: @DEFAULT_LOGFILED@
4443 LOC: Log::TheConfig.logfile_daemon
4445 Specify the path to the logfile-writing daemon. This daemon is
4446 used to write the access and store logs, if configured.
4448 Squid sends a number of commands to the log daemon:
4449 L<data>\n - logfile data
4454 r<n>\n - set rotate count to <n>
4455 b<n>\n - 1 = buffer output, 0 = don't buffer output
4457 No responses is expected.
4460 NAME: stats_collection
4462 LOC: Config.accessList.stats_collection
4464 DEFAULT_DOC: Allow logging for all transactions.
4465 COMMENT: allow|deny acl acl...
4467 This options allows you to control which requests gets accounted
4468 in performance counters.
4470 This clause only supports fast acl types.
4471 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4474 NAME: cache_store_log
4477 LOC: Config.Log.store
4479 Logs the activities of the storage manager. Shows which
4480 objects are ejected from the cache, and which objects are
4481 saved and for how long.
4482 There are not really utilities to analyze this data, so you can safely
4483 disable it (the default).
4485 Store log uses modular logging outputs. See access_log for the list
4486 of modules supported.
4489 cache_store_log stdio:@DEFAULT_STORE_LOG@
4490 cache_store_log daemon:@DEFAULT_STORE_LOG@
4493 NAME: cache_swap_state cache_swap_log
4495 LOC: Config.Log.swap
4497 DEFAULT_DOC: Store the journal inside its cache_dir
4499 Location for the cache "swap.state" file. This index file holds
4500 the metadata of objects saved on disk. It is used to rebuild
4501 the cache during startup. Normally this file resides in each
4502 'cache_dir' directory, but you may specify an alternate
4503 pathname here. Note you must give a full filename, not just
4504 a directory. Since this is the index for the whole object
4505 list you CANNOT periodically rotate it!
4507 If %s can be used in the file name it will be replaced with a
4508 a representation of the cache_dir name where each / is replaced
4509 with '.'. This is needed to allow adding/removing cache_dir
4510 lines when cache_swap_log is being used.
4512 If have more than one 'cache_dir', and %s is not used in the name
4513 these swap logs will have names such as:
4519 The numbered extension (which is added automatically)
4520 corresponds to the order of the 'cache_dir' lines in this
4521 configuration file. If you change the order of the 'cache_dir'
4522 lines in this file, these index files will NOT correspond to
4523 the correct 'cache_dir' entry (unless you manually rename
4524 them). We recommend you do NOT use this option. It is
4525 better to keep these index files in each 'cache_dir' directory.
4528 NAME: logfile_rotate
4531 LOC: Config.Log.rotateNumber
4533 Specifies the default number of logfile rotations to make when you
4534 type 'squid -k rotate'. The default is 10, which will rotate
4535 with extensions 0 through 9. Setting logfile_rotate to 0 will
4536 disable the file name rotation, but the logfiles are still closed
4537 and re-opened. This will enable you to rename the logfiles
4538 yourself just before sending the rotate signal.
4540 Note, from Squid-3.1 this option is only a default for cache.log,
4541 that log can be rotated separately by using debug_options.
4543 Note, from Squid-3.6 this option is only a default for access.log
4544 recorded by stdio: module. Those logs can be rotated separately by
4545 using the rotate=N option on their access_log directive.
4547 Note, the 'squid -k rotate' command normally sends a USR1
4548 signal to the running squid process. In certain situations
4549 (e.g. on Linux with Async I/O), USR1 is used for other
4550 purposes, so -k rotate uses another signal. It is best to get
4551 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4558 DEFAULT: @DEFAULT_MIME_TABLE@
4559 LOC: Config.mimeTablePathname
4561 Path to Squid's icon configuration file.
4563 You shouldn't need to change this, but the default file contains
4564 examples and formatting information if you do.
4570 LOC: Config.onoff.log_mime_hdrs
4573 The Cache can record both the request and the response MIME
4574 headers for each HTTP transaction. The headers are encoded
4575 safely and will appear as two bracketed fields at the end of
4576 the access log (for either the native or httpd-emulated log
4577 formats). To enable this logging set log_mime_hdrs to 'on'.
4582 DEFAULT: @DEFAULT_PID_FILE@
4583 LOC: Config.pidFilename
4585 A filename to write the process-id to. To disable, enter "none".
4588 NAME: client_netmask
4590 LOC: Config.Addrs.client_netmask
4592 DEFAULT_DOC: Log full client IP address
4594 A netmask for client addresses in logfiles and cachemgr output.
4595 Change this to protect the privacy of your cache clients.
4596 A netmask of 255.255.255.0 will log all IP's in that range with
4597 the last digit set to '0'.
4600 NAME: strip_query_terms
4602 LOC: Config.onoff.strip_query_terms
4605 By default, Squid strips query terms from requested URLs before
4606 logging. This protects your user's privacy and reduces log size.
4608 When investigating HIT/MISS or other caching behaviour you
4609 will need to disable this to see the full URL used by Squid.
4616 LOC: Config.onoff.buffered_logs
4618 Whether to write/send access_log records ASAP or accumulate them and
4619 then write/send them in larger chunks. Buffering may improve
4620 performance because it decreases the number of I/Os. However,
4621 buffering increases the delay before log records become available to
4622 the final recipient (e.g., a disk file or logging daemon) and,
4623 hence, increases the risk of log records loss.
4625 Note that even when buffered_logs are off, Squid may have to buffer
4626 records if it cannot write/send them immediately due to pending I/Os
4627 (e.g., the I/O writing the previous log record) or connectivity loss.
4629 Currently honored by 'daemon' and 'tcp' access_log modules only.
4632 NAME: netdb_filename
4634 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4635 LOC: Config.netdbFilename
4638 Where Squid stores it's netdb journal.
4639 When enabled this journal preserves netdb state between restarts.
4641 To disable, enter "none".
4645 OPTIONS FOR TROUBLESHOOTING
4646 -----------------------------------------------------------------------------
4651 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4652 LOC: Debug::cache_log
4654 Squid administrative logging file.
4656 This is where general information about Squid behavior goes. You can
4657 increase the amount of data logged to this file and how often it is
4658 rotated with "debug_options"
4664 DEFAULT_DOC: Log all critical and important messages.
4665 LOC: Debug::debugOptions
4667 Logging options are set as section,level where each source file
4668 is assigned a unique section. Lower levels result in less
4669 output, Full debugging (level 9) can result in a very large
4670 log file, so be careful.
4672 The magic word "ALL" sets debugging levels for all sections.
4673 The default is to run with "ALL,1" to record important warnings.
4675 The rotate=N option can be used to keep more or less of these logs
4676 than would otherwise be kept by logfile_rotate.
4677 For most uses a single log should be enough to monitor current
4678 events affecting Squid.
4683 LOC: Config.coredump_dir
4684 DEFAULT_IF_NONE: none
4685 DEFAULT_DOC: Use the directory from where Squid was started.
4687 By default Squid leaves core files in the directory from where
4688 it was started. If you set 'coredump_dir' to a directory
4689 that exists, Squid will chdir() to that directory at startup
4690 and coredump files will be left there.
4694 # Leave coredumps in the first cache dir
4695 coredump_dir @DEFAULT_SWAP_DIR@
4701 OPTIONS FOR FTP GATEWAYING
4702 -----------------------------------------------------------------------------
4708 LOC: Config.Ftp.anon_user
4710 If you want the anonymous login password to be more informative
4711 (and enable the use of picky FTP servers), set this to something
4712 reasonable for your domain, like wwwuser@somewhere.net
4714 The reason why this is domainless by default is the
4715 request can be made on the behalf of a user in any domain,
4716 depending on how the cache is used.
4717 Some FTP server also validate the email address is valid
4718 (for example perl.com).
4724 LOC: Config.Ftp.passive
4726 If your firewall does not allow Squid to use passive
4727 connections, turn off this option.
4729 Use of ftp_epsv_all option requires this to be ON.
4735 LOC: Config.Ftp.epsv_all
4737 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4739 NATs may be able to put the connection on a "fast path" through the
4740 translator, as the EPRT command will never be used and therefore,
4741 translation of the data portion of the segments will never be needed.
4743 When a client only expects to do two-way FTP transfers this may be
4745 If squid finds that it must do a three-way FTP transfer after issuing
4746 an EPSV ALL command, the FTP session will fail.
4748 If you have any doubts about this option do not use it.
4749 Squid will nicely attempt all other connection methods.
4751 Requires ftp_passive to be ON (default) for any effect.
4757 LOC: Config.accessList.ftp_epsv
4759 FTP Protocol extensions permit the use of a special "EPSV" command.
4761 NATs may be able to put the connection on a "fast path" through the
4762 translator using EPSV, as the EPRT command will never be used
4763 and therefore, translation of the data portion of the segments
4764 will never be needed.
4766 EPSV is often required to interoperate with FTP servers on IPv6
4767 networks. On the other hand, it may break some IPv4 servers.
4769 By default, EPSV may try EPSV with any FTP server. To fine tune
4770 that decision, you may restrict EPSV to certain clients or servers
4773 ftp_epsv allow|deny al1 acl2 ...
4775 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
4777 Only fast ACLs are supported.
4778 Requires ftp_passive to be ON (default) for any effect.
4784 LOC: Config.Ftp.eprt
4786 FTP Protocol extensions permit the use of a special "EPRT" command.
4788 This extension provides a protocol neutral alternative to the
4789 IPv4-only PORT command. When supported it enables active FTP data
4790 channels over IPv6 and efficient NAT handling.
4792 Turning this OFF will prevent EPRT being attempted and will skip
4793 straight to using PORT for IPv4 servers.
4795 Some devices are known to not handle this extension correctly and
4796 may result in crashes. Devices which suport EPRT enough to fail
4797 cleanly will result in Squid attempting PORT anyway. This directive
4798 should only be disabled when EPRT results in device failures.
4800 WARNING: Doing so will convert Squid back to the old behavior with all
4801 the related problems with external NAT devices/layers and IPv4-only FTP.
4804 NAME: ftp_sanitycheck
4807 LOC: Config.Ftp.sanitycheck
4809 For security and data integrity reasons Squid by default performs
4810 sanity checks of the addresses of FTP data connections ensure the
4811 data connection is to the requested server. If you need to allow
4812 FTP connections to servers using another IP address for the data
4813 connection turn this off.
4816 NAME: ftp_telnet_protocol
4819 LOC: Config.Ftp.telnet
4821 The FTP protocol is officially defined to use the telnet protocol
4822 as transport channel for the control connection. However, many
4823 implementations are broken and does not respect this aspect of
4826 If you have trouble accessing files with ASCII code 255 in the
4827 path or similar problems involving this ASCII code you can
4828 try setting this directive to off. If that helps, report to the
4829 operator of the FTP server in question that their FTP server
4830 is broken and does not follow the FTP standard.
4834 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4835 -----------------------------------------------------------------------------
4840 DEFAULT: @DEFAULT_DISKD@
4841 LOC: Config.Program.diskd
4843 Specify the location of the diskd executable.
4844 Note this is only useful if you have compiled in
4845 diskd as one of the store io modules.
4848 NAME: unlinkd_program
4851 DEFAULT: @DEFAULT_UNLINKD@
4852 LOC: Config.Program.unlinkd
4854 Specify the location of the executable for file deletion process.
4857 NAME: pinger_program
4859 DEFAULT: @DEFAULT_PINGER@
4860 LOC: Config.pinger.program
4863 Specify the location of the executable for the pinger process.
4869 LOC: Config.pinger.enable
4872 Control whether the pinger is active at run-time.
4873 Enables turning ICMP pinger on and off with a simple
4874 squid -k reconfigure.
4879 OPTIONS FOR URL REWRITING
4880 -----------------------------------------------------------------------------
4883 NAME: url_rewrite_program redirect_program
4885 LOC: Config.Program.redirect
4888 Specify the location of the executable URL rewriter to use.
4889 Since they can perform almost any function there isn't one included.
4891 For each requested URL, the rewriter will receive on line with the format
4893 [channel-ID <SP>] URL [<SP> extras]<NL>
4895 See url_rewrite_extras on how to send "extras" with optional values to
4897 After processing the request the helper must reply using the following format:
4899 [channel-ID <SP>] result [<SP> kv-pairs]
4901 The result code can be:
4903 OK status=30N url="..."
4904 Redirect the URL to the one supplied in 'url='.
4905 'status=' is optional and contains the status code to send
4906 the client in Squids HTTP response. It must be one of the
4907 HTTP redirect status codes: 301, 302, 303, 307, 308.
4908 When no status is given Squid will use 302.
4910 OK rewrite-url="..."
4911 Rewrite the URL to the one supplied in 'rewrite-url='.
4912 The new URL is fetched directly by Squid and returned to
4913 the client as the response to its request.
4916 When neither of url= and rewrite-url= are sent Squid does
4920 Do not change the URL.
4923 An internal error occurred in the helper, preventing
4924 a result being identified. The 'message=' key name is
4925 reserved for delivering a log message.
4928 In addition to the above kv-pairs Squid also understands the following
4929 optional kv-pairs received from URL rewriters:
4931 Associates a TAG with the client TCP connection.
4932 The TAG is treated as a regular annotation but persists across
4933 future requests on the client connection rather than just the
4934 current request. A helper may update the TAG during subsequent
4935 requests be returning a new kv-pair.
4937 When using the concurrency= option the protocol is changed by
4938 introducing a query channel tag in front of the request/response.
4939 The query channel tag is a number between 0 and concurrency-1.
4940 This value must be echoed back unchanged to Squid as the first part
4941 of the response relating to its request.
4943 WARNING: URL re-writing ability should be avoided whenever possible.
4944 Use the URL redirect form of response instead.
4946 Re-write creates a difference in the state held by the client
4947 and server. Possibly causing confusion when the server response
4948 contains snippets of its view state. Embeded URLs, response
4949 and content Location headers, etc. are not re-written by this
4952 By default, a URL rewriter is not used.
4955 NAME: url_rewrite_children redirect_children
4956 TYPE: HelperChildConfig
4957 DEFAULT: 20 startup=0 idle=1 concurrency=0
4958 LOC: Config.redirectChildren
4960 The maximum number of redirector processes to spawn. If you limit
4961 it too few Squid will have to wait for them to process a backlog of
4962 URLs, slowing it down. If you allow too many they will use RAM
4963 and other system resources noticably.
4965 The startup= and idle= options allow some measure of skew in your
4970 Sets a minimum of how many processes are to be spawned when Squid
4971 starts or reconfigures. When set to zero the first request will
4972 cause spawning of the first child process to handle it.
4974 Starting too few will cause an initial slowdown in traffic as Squid
4975 attempts to simultaneously spawn enough processes to cope.
4979 Sets a minimum of how many processes Squid is to try and keep available
4980 at all times. When traffic begins to rise above what the existing
4981 processes can handle this many more will be spawned up to the maximum
4982 configured. A minimum setting of 1 is required.
4986 The number of requests each redirector helper can handle in
4987 parallel. Defaults to 0 which indicates the redirector
4988 is a old-style single threaded redirector.
4990 When this directive is set to a value >= 1 then the protocol
4991 used to communicate with the helper is modified to include
4992 an ID in front of the request/response. The ID from the request
4993 must be echoed back with the response to that request.
4997 Sets the maximum number of queued requests.
4998 If the queued requests exceed queue size and redirector_bypass
4999 configuration option is set, then redirector is bypassed. Otherwise, if
5000 overloading persists squid may abort its operation.
5001 The default value is set to 2*numberofchildren.
5004 NAME: url_rewrite_host_header redirect_rewrites_host_header
5007 LOC: Config.onoff.redir_rewrites_host
5009 To preserve same-origin security policies in browsers and
5010 prevent Host: header forgery by redirectors Squid rewrites
5011 any Host: header in redirected requests.
5013 If you are running an accelerator this may not be a wanted
5014 effect of a redirector. This directive enables you disable
5015 Host: alteration in reverse-proxy traffic.
5017 WARNING: Entries are cached on the result of the URL rewriting
5018 process, so be careful if you have domain-virtual hosts.
5020 WARNING: Squid and other software verifies the URL and Host
5021 are matching, so be careful not to relay through other proxies
5022 or inspecting firewalls with this disabled.
5025 NAME: url_rewrite_access redirector_access
5028 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5029 LOC: Config.accessList.redirector
5031 If defined, this access list specifies which requests are
5032 sent to the redirector processes.
5034 This clause supports both fast and slow acl types.
5035 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5038 NAME: url_rewrite_bypass redirector_bypass
5040 LOC: Config.onoff.redirector_bypass
5043 When this is 'on', a request will not go through the
5044 redirector if all the helpers are busy. If this is 'off'
5045 and the redirector queue grows too large, Squid will exit
5046 with a FATAL error and ask you to increase the number of
5047 redirectors. You should only enable this if the redirectors
5048 are not critical to your caching system. If you use
5049 redirectors for access control, and you enable this option,
5050 users may have access to pages they should not
5051 be allowed to request.
5052 This options sets default queue-size option of the url_rewrite_children
5056 NAME: url_rewrite_extras
5057 TYPE: TokenOrQuotedString
5058 LOC: Config.redirector_extras
5059 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5061 Specifies a string to be append to request line format for the
5062 rewriter helper. "Quoted" format values may contain spaces and
5063 logformat %macros. In theory, any logformat %macro can be used.
5064 In practice, a %macro expands as a dash (-) if the helper request is
5065 sent before the required macro information is available to Squid.
5068 NAME: url_rewrite_timeout
5069 TYPE: UrlHelperTimeout
5070 LOC: Config.onUrlRewriteTimeout
5072 DEFAULT_DOC: Squid waits for the helper response forever
5074 Squid times active requests to redirector. The timeout value and Squid
5075 reaction to a timed out request are configurable using the following
5078 url_rewrite_timeout timeout time-units on_timeout=<action> [response=<quoted-response>]
5080 supported timeout actions:
5081 fail Squid return a ERR_GATEWAY_FAILURE error page
5083 bypass Do not re-write the URL
5085 retry Send the lookup to the helper again
5087 use_configured_response
5088 Use the <quoted-response> as helper response
5092 OPTIONS FOR STORE ID
5093 -----------------------------------------------------------------------------
5096 NAME: store_id_program storeurl_rewrite_program
5098 LOC: Config.Program.store_id
5101 Specify the location of the executable StoreID helper to use.
5102 Since they can perform almost any function there isn't one included.
5104 For each requested URL, the helper will receive one line with the format
5106 [channel-ID <SP>] URL [<SP> extras]<NL>
5109 After processing the request the helper must reply using the following format:
5111 [channel-ID <SP>] result [<SP> kv-pairs]
5113 The result code can be:
5116 Use the StoreID supplied in 'store-id='.
5119 The default is to use HTTP request URL as the store ID.
5122 An internal error occured in the helper, preventing
5123 a result being identified.
5125 In addition to the above kv-pairs Squid also understands the following
5126 optional kv-pairs received from URL rewriters:
5128 Associates a TAG with the client TCP connection.
5129 Please see url_rewrite_program related documentation for this
5132 Helper programs should be prepared to receive and possibly ignore
5133 additional whitespace-separated tokens on each input line.
5135 When using the concurrency= option the protocol is changed by
5136 introducing a query channel tag in front of the request/response.
5137 The query channel tag is a number between 0 and concurrency-1.
5138 This value must be echoed back unchanged to Squid as the first part
5139 of the response relating to its request.
5141 NOTE: when using StoreID refresh_pattern will apply to the StoreID
5142 returned from the helper and not the URL.
5144 WARNING: Wrong StoreID value returned by a careless helper may result
5145 in the wrong cached response returned to the user.
5147 By default, a StoreID helper is not used.
5150 NAME: store_id_extras
5151 TYPE: TokenOrQuotedString
5152 LOC: Config.storeId_extras
5153 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5155 Specifies a string to be append to request line format for the
5156 StoreId helper. "Quoted" format values may contain spaces and
5157 logformat %macros. In theory, any logformat %macro can be used.
5158 In practice, a %macro expands as a dash (-) if the helper request is
5159 sent before the required macro information is available to Squid.
5162 NAME: store_id_children storeurl_rewrite_children
5163 TYPE: HelperChildConfig
5164 DEFAULT: 20 startup=0 idle=1 concurrency=0
5165 LOC: Config.storeIdChildren
5167 The maximum number of StoreID helper processes to spawn. If you limit
5168 it too few Squid will have to wait for them to process a backlog of
5169 requests, slowing it down. If you allow too many they will use RAM
5170 and other system resources noticably.
5172 The startup= and idle= options allow some measure of skew in your
5177 Sets a minimum of how many processes are to be spawned when Squid
5178 starts or reconfigures. When set to zero the first request will
5179 cause spawning of the first child process to handle it.
5181 Starting too few will cause an initial slowdown in traffic as Squid
5182 attempts to simultaneously spawn enough processes to cope.
5186 Sets a minimum of how many processes Squid is to try and keep available
5187 at all times. When traffic begins to rise above what the existing
5188 processes can handle this many more will be spawned up to the maximum
5189 configured. A minimum setting of 1 is required.
5193 The number of requests each storeID helper can handle in
5194 parallel. Defaults to 0 which indicates the helper
5195 is a old-style single threaded program.
5197 When this directive is set to a value >= 1 then the protocol
5198 used to communicate with the helper is modified to include
5199 an ID in front of the request/response. The ID from the request
5200 must be echoed back with the response to that request.
5204 Sets the maximum number of queued requests.
5205 If the queued requests exceed queue size and store_id_bypass
5206 configuration option is set, then storeID helper is bypassed. Otherwise,
5207 if overloading persists squid may abort its operation.
5208 The default value is set to 2*numberofchildren.
5211 NAME: store_id_access storeurl_rewrite_access
5214 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5215 LOC: Config.accessList.store_id
5217 If defined, this access list specifies which requests are
5218 sent to the StoreID processes. By default all requests
5221 This clause supports both fast and slow acl types.
5222 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5225 NAME: store_id_bypass storeurl_rewrite_bypass
5227 LOC: Config.onoff.store_id_bypass
5230 When this is 'on', a request will not go through the
5231 helper if all helpers are busy. If this is 'off'
5232 and the helper queue grows too large, Squid will exit
5233 with a FATAL error and ask you to increase the number of
5234 helpers. You should only enable this if the helperss
5235 are not critical to your caching system. If you use
5236 helpers for critical caching components, and you enable this
5237 option, users may not get objects from cache.
5238 This options sets default queue-size option of the store_id_children
5243 OPTIONS FOR TUNING THE CACHE
5244 -----------------------------------------------------------------------------
5247 NAME: cache no_cache
5250 DEFAULT_DOC: By default, this directive is unused and has no effect.
5251 LOC: Config.accessList.noCache
5253 Requests denied by this directive will not be served from the cache
5254 and their responses will not be stored in the cache. This directive
5255 has no effect on other transactions and on already cached responses.
5257 This clause supports both fast and slow acl types.
5258 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5260 This and the two other similar caching directives listed below are
5261 checked at different transaction processing stages, have different
5262 access to response information, affect different cache operations,
5263 and differ in slow ACLs support:
5265 * cache: Checked before Squid makes a hit/miss determination.
5266 No access to reply information!
5267 Denies both serving a hit and storing a miss.
5268 Supports both fast and slow ACLs.
5269 * send_hit: Checked after a hit was detected.
5270 Has access to reply (hit) information.
5271 Denies serving a hit only.
5272 Supports fast ACLs only.
5273 * store_miss: Checked before storing a cachable miss.
5274 Has access to reply (miss) information.
5275 Denies storing a miss only.
5276 Supports fast ACLs only.
5278 If you are not sure which of the three directives to use, apply the
5279 following decision logic:
5281 * If your ACL(s) are of slow type _and_ need response info, redesign.
5282 Squid does not support that particular combination at this time.
5284 * If your directive ACL(s) are of slow type, use "cache"; and/or
5285 * if your directive ACL(s) need no response info, use "cache".
5287 * If you do not want the response cached, use store_miss; and/or
5288 * if you do not want a hit on a cached response, use send_hit.
5294 DEFAULT_DOC: By default, this directive is unused and has no effect.
5295 LOC: Config.accessList.sendHit
5297 Responses denied by this directive will not be served from the cache
5298 (but may still be cached, see store_miss). This directive has no
5299 effect on the responses it allows and on the cached objects.
5301 Please see the "cache" directive for a summary of differences among
5302 store_miss, send_hit, and cache directives.
5304 Unlike the "cache" directive, send_hit only supports fast acl
5305 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5309 # apply custom Store ID mapping to some URLs
5310 acl MapMe dstdomain .c.example.com
5311 store_id_program ...
5312 store_id_access allow MapMe
5314 # but prevent caching of special responses
5315 # such as 302 redirects that cause StoreID loops
5316 acl Ordinary http_status 200-299
5317 store_miss deny MapMe !Ordinary
5319 # and do not serve any previously stored special responses
5320 # from the cache (in case they were already cached before
5321 # the above store_miss rule was in effect).
5322 send_hit deny MapMe !Ordinary
5328 DEFAULT_DOC: By default, this directive is unused and has no effect.
5329 LOC: Config.accessList.storeMiss
5331 Responses denied by this directive will not be cached (but may still
5332 be served from the cache, see send_hit). This directive has no
5333 effect on the responses it allows and on the already cached responses.
5335 Please see the "cache" directive for a summary of differences among
5336 store_miss, send_hit, and cache directives. See the
5337 send_hit directive for a usage example.
5339 Unlike the "cache" directive, store_miss only supports fast acl
5340 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5346 LOC: Config.maxStale
5349 This option puts an upper limit on how stale content Squid
5350 will serve from the cache if cache validation fails.
5351 Can be overriden by the refresh_pattern max-stale option.
5354 NAME: refresh_pattern
5355 TYPE: refreshpattern
5359 usage: refresh_pattern [-i] regex min percent max [options]
5361 By default, regular expressions are CASE-SENSITIVE. To make
5362 them case-insensitive, use the -i option.
5364 'Min' is the time (in minutes) an object without an explicit
5365 expiry time should be considered fresh. The recommended
5366 value is 0, any higher values may cause dynamic applications
5367 to be erroneously cached unless the application designer
5368 has taken the appropriate actions.
5370 'Percent' is a percentage of the objects age (time since last
5371 modification age) an object without explicit expiry time
5372 will be considered fresh.
5374 'Max' is an upper limit on how long objects without an explicit
5375 expiry time will be considered fresh.
5377 options: override-expire
5382 ignore-must-revalidate
5389 override-expire enforces min age even if the server
5390 sent an explicit expiry time (e.g., with the
5391 Expires: header or Cache-Control: max-age). Doing this
5392 VIOLATES the HTTP standard. Enabling this feature
5393 could make you liable for problems which it causes.
5395 Note: override-expire does not enforce staleness - it only extends
5396 freshness / min. If the server returns a Expires time which
5397 is longer than your max time, Squid will still consider
5398 the object fresh for that period of time.
5400 override-lastmod enforces min age even on objects
5401 that were modified recently.
5403 reload-into-ims changes a client no-cache or ``reload''
5404 request for a cached entry into a conditional request using
5405 If-Modified-Since and/or If-None-Match headers, provided the
5406 cached entry has a Last-Modified and/or a strong ETag header.
5407 Doing this VIOLATES the HTTP standard. Enabling this feature
5408 could make you liable for problems which it causes.
5410 ignore-reload ignores a client no-cache or ``reload''
5411 header. Doing this VIOLATES the HTTP standard. Enabling
5412 this feature could make you liable for problems which
5415 ignore-no-store ignores any ``Cache-control: no-store''
5416 headers received from a server. Doing this VIOLATES
5417 the HTTP standard. Enabling this feature could make you
5418 liable for problems which it causes.
5420 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
5421 headers received from a server. Doing this VIOLATES
5422 the HTTP standard. Enabling this feature could make you
5423 liable for problems which it causes.
5425 ignore-private ignores any ``Cache-control: private''
5426 headers received from a server. Doing this VIOLATES
5427 the HTTP standard. Enabling this feature could make you
5428 liable for problems which it causes.
5430 ignore-auth caches responses to requests with authorization,
5431 as if the originserver had sent ``Cache-control: public''
5432 in the response header. Doing this VIOLATES the HTTP standard.
5433 Enabling this feature could make you liable for problems which
5436 refresh-ims causes squid to contact the origin server
5437 when a client issues an If-Modified-Since request. This
5438 ensures that the client will receive an updated version
5439 if one is available.
5441 store-stale stores responses even if they don't have explicit
5442 freshness or a validator (i.e., Last-Modified or an ETag)
5443 present, or if they're already stale. By default, Squid will
5444 not cache such responses because they usually can't be
5445 reused. Note that such responses will be stale by default.
5447 max-stale=NN provide a maximum staleness factor. Squid won't
5448 serve objects more stale than this even if it failed to
5449 validate the object. Default: use the max_stale global limit.
5451 Basically a cached object is:
5453 FRESH if expires < now, else STALE
5455 FRESH if lm-factor < percent, else STALE
5459 The refresh_pattern lines are checked in the order listed here.
5460 The first entry which matches is used. If none of the entries
5461 match the default will be used.
5463 Note, you must uncomment all the default lines if you want
5464 to change one. The default setting is only active if none is
5470 # Add any of your own refresh_pattern entries above these.
5472 refresh_pattern ^ftp: 1440 20% 10080
5473 refresh_pattern ^gopher: 1440 0% 1440
5474 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5475 refresh_pattern . 0 20% 4320
5479 NAME: quick_abort_min
5483 LOC: Config.quickAbort.min
5486 NAME: quick_abort_max
5490 LOC: Config.quickAbort.max
5493 NAME: quick_abort_pct
5497 LOC: Config.quickAbort.pct
5499 The cache by default continues downloading aborted requests
5500 which are almost completed (less than 16 KB remaining). This
5501 may be undesirable on slow (e.g. SLIP) links and/or very busy
5502 caches. Impatient users may tie up file descriptors and
5503 bandwidth by repeatedly requesting and immediately aborting
5506 When the user aborts a request, Squid will check the
5507 quick_abort values to the amount of data transferred until
5510 If the transfer has less than 'quick_abort_min' KB remaining,
5511 it will finish the retrieval.
5513 If the transfer has more than 'quick_abort_max' KB remaining,
5514 it will abort the retrieval.
5516 If more than 'quick_abort_pct' of the transfer has completed,
5517 it will finish the retrieval.
5519 If you do not want any retrieval to continue after the client
5520 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5523 If you want retrievals to always continue if they are being
5524 cached set 'quick_abort_min' to '-1 KB'.
5527 NAME: read_ahead_gap
5528 COMMENT: buffer-size
5530 LOC: Config.readAheadGap
5533 The amount of data the cache will buffer ahead of what has been
5534 sent to the client when retrieving an object from another server.
5538 IFDEF: USE_HTTP_VIOLATIONS
5541 LOC: Config.negativeTtl
5544 Set the Default Time-to-Live (TTL) for failed requests.
5545 Certain types of failures (such as "connection refused" and
5546 "404 Not Found") are able to be negatively-cached for a short time.
5547 Modern web servers should provide Expires: header, however if they
5548 do not this can provide a minimum TTL.
5549 The default is not to cache errors with unknown expiry details.
5551 Note that this is different from negative caching of DNS lookups.
5553 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5554 this feature could make you liable for problems which it
5558 NAME: positive_dns_ttl
5561 LOC: Config.positiveDnsTtl
5564 Upper limit on how long Squid will cache positive DNS responses.
5565 Default is 6 hours (360 minutes). This directive must be set
5566 larger than negative_dns_ttl.
5569 NAME: negative_dns_ttl
5572 LOC: Config.negativeDnsTtl
5575 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5576 This also sets the lower cache limit on positive lookups.
5577 Minimum value is 1 second, and it is not recommendable to go
5578 much below 10 seconds.
5581 NAME: range_offset_limit
5582 COMMENT: size [acl acl...]
5584 LOC: Config.rangeOffsetLimit
5587 usage: (size) [units] [[!]aclname]
5589 Sets an upper limit on how far (number of bytes) into the file
5590 a Range request may be to cause Squid to prefetch the whole file.
5591 If beyond this limit, Squid forwards the Range request as it is and
5592 the result is NOT cached.
5594 This is to stop a far ahead range request (lets say start at 17MB)
5595 from making Squid fetch the whole object up to that point before
5596 sending anything to the client.
5598 Multiple range_offset_limit lines may be specified, and they will
5599 be searched from top to bottom on each request until a match is found.
5600 The first match found will be used. If no line matches a request, the
5601 default limit of 0 bytes will be used.
5603 'size' is the limit specified as a number of units.
5605 'units' specifies whether to use bytes, KB, MB, etc.
5606 If no units are specified bytes are assumed.
5608 A size of 0 causes Squid to never fetch more than the
5609 client requested. (default)
5611 A size of 'none' causes Squid to always fetch the object from the
5612 beginning so it may cache the result. (2.0 style)
5614 'aclname' is the name of a defined ACL.
5616 NP: Using 'none' as the byte value here will override any quick_abort settings
5617 that may otherwise apply to the range request. The range request will
5618 be fully fetched from start to finish regardless of the client
5619 actions. This affects bandwidth usage.
5622 NAME: minimum_expiry_time
5625 LOC: Config.minimum_expiry_time
5628 The minimum caching time according to (Expires - Date)
5629 headers Squid honors if the object can't be revalidated.
5630 The default is 60 seconds.
5632 In reverse proxy environments it might be desirable to honor
5633 shorter object lifetimes. It is most likely better to make
5634 your server return a meaningful Last-Modified header however.
5636 In ESI environments where page fragments often have short
5637 lifetimes, this will often be best set to 0.
5640 NAME: store_avg_object_size
5644 LOC: Config.Store.avgObjectSize
5646 Average object size, used to estimate number of objects your
5647 cache can hold. The default is 13 KB.
5649 This is used to pre-seed the cache index memory allocation to
5650 reduce expensive reallocate operations while handling clients
5651 traffic. Too-large values may result in memory allocation during
5652 peak traffic, too-small values will result in wasted memory.
5654 Check the cache manager 'info' report metrics for the real
5655 object sizes seen by your Squid before tuning this.
5658 NAME: store_objects_per_bucket
5661 LOC: Config.Store.objectsPerBucket
5663 Target number of objects per bucket in the store hash table.
5664 Lowering this value increases the total number of buckets and
5665 also the storage maintenance rate. The default is 20.
5670 -----------------------------------------------------------------------------
5673 NAME: request_header_max_size
5677 LOC: Config.maxRequestHeaderSize
5679 This specifies the maximum size for HTTP headers in a request.
5680 Request headers are usually relatively small (about 512 bytes).
5681 Placing a limit on the request header size will catch certain
5682 bugs (for example with persistent connections) and possibly
5683 buffer-overflow or denial-of-service attacks.
5686 NAME: reply_header_max_size
5690 LOC: Config.maxReplyHeaderSize
5692 This specifies the maximum size for HTTP headers in a reply.
5693 Reply headers are usually relatively small (about 512 bytes).
5694 Placing a limit on the reply header size will catch certain
5695 bugs (for example with persistent connections) and possibly
5696 buffer-overflow or denial-of-service attacks.
5699 NAME: request_body_max_size
5703 DEFAULT_DOC: No limit.
5704 LOC: Config.maxRequestBodySize
5706 This specifies the maximum size for an HTTP request body.
5707 In other words, the maximum size of a PUT/POST request.
5708 A user who attempts to send a request with a body larger
5709 than this limit receives an "Invalid Request" error message.
5710 If you set this parameter to a zero (the default), there will
5711 be no limit imposed.
5713 See also client_request_buffer_max_size for an alternative
5714 limitation on client uploads which can be configured.
5717 NAME: client_request_buffer_max_size
5721 LOC: Config.maxRequestBufferSize
5723 This specifies the maximum buffer size of a client request.
5724 It prevents squid eating too much memory when somebody uploads
5729 IFDEF: USE_HTTP_VIOLATIONS
5732 DEFAULT_DOC: Obey RFC 2616.
5733 LOC: Config.accessList.brokenPosts
5735 A list of ACL elements which, if matched, causes Squid to send
5736 an extra CRLF pair after the body of a PUT/POST request.
5738 Some HTTP servers has broken implementations of PUT/POST,
5739 and rely on an extra CRLF pair sent by some WWW clients.
5741 Quote from RFC2616 section 4.1 on this matter:
5743 Note: certain buggy HTTP/1.0 client implementations generate an
5744 extra CRLF's after a POST request. To restate what is explicitly
5745 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5746 a request with an extra CRLF.
5748 This clause only supports fast acl types.
5749 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5752 acl buggy_server url_regex ^http://....
5753 broken_posts allow buggy_server
5756 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5759 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5761 LOC: Adaptation::Config::use_indirect_client
5763 Controls whether the indirect client IP address (instead of the direct
5764 client IP address) is passed to adaptation services.
5766 See also: follow_x_forwarded_for adaptation_send_client_ip
5770 IFDEF: USE_HTTP_VIOLATIONS
5774 LOC: Config.onoff.via
5776 If set (default), Squid will include a Via header in requests and
5777 replies as required by RFC2616.
5783 LOC: Config.onoff.ie_refresh
5786 Microsoft Internet Explorer up until version 5.5 Service
5787 Pack 1 has an issue with transparent proxies, wherein it
5788 is impossible to force a refresh. Turning this on provides
5789 a partial fix to the problem, by causing all IMS-REFRESH
5790 requests from older IE versions to check the origin server
5791 for fresh content. This reduces hit ratio by some amount
5792 (~10% in my experience), but allows users to actually get
5793 fresh content when they want it. Note because Squid
5794 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5795 of 5.5 is unchanged from old versions of Squid (i.e. a
5796 forced refresh is impossible). Newer versions of IE will,
5797 hopefully, continue to have the new behavior and will be
5798 handled based on that assumption. This option defaults to
5799 the old Squid behavior, which is better for hit ratios but
5800 worse for clients using IE, if they need to be able to
5801 force fresh content.
5804 NAME: vary_ignore_expire
5807 LOC: Config.onoff.vary_ignore_expire
5810 Many HTTP servers supporting Vary gives such objects
5811 immediate expiry time with no cache-control header
5812 when requested by a HTTP/1.0 client. This option
5813 enables Squid to ignore such expiry times until
5814 HTTP/1.1 is fully implemented.
5816 WARNING: If turned on this may eventually cause some
5817 varying objects not intended for caching to get cached.
5820 NAME: request_entities
5822 LOC: Config.onoff.request_entities
5825 Squid defaults to deny GET and HEAD requests with request entities,
5826 as the meaning of such requests are undefined in the HTTP standard
5827 even if not explicitly forbidden.
5829 Set this directive to on if you have clients which insists
5830 on sending request entities in GET or HEAD requests. But be warned
5831 that there is server software (both proxies and web servers) which
5832 can fail to properly process this kind of request which may make you
5833 vulnerable to cache pollution attacks if enabled.
5836 NAME: request_header_access
5837 IFDEF: USE_HTTP_VIOLATIONS
5838 TYPE: http_header_access
5839 LOC: Config.request_header_access
5841 DEFAULT_DOC: No limits.
5843 Usage: request_header_access header_name allow|deny [!]aclname ...
5845 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5846 this feature could make you liable for problems which it
5849 This option replaces the old 'anonymize_headers' and the
5850 older 'http_anonymizer' option with something that is much
5851 more configurable. A list of ACLs for each header name allows
5852 removal of specific header fields under specific conditions.
5854 This option only applies to outgoing HTTP request headers (i.e.,
5855 headers sent by Squid to the next HTTP hop such as a cache peer
5856 or an origin server). The option has no effect during cache hit
5857 detection. The equivalent adaptation vectoring point in ICAP
5858 terminology is post-cache REQMOD.
5860 The option is applied to individual outgoing request header
5861 fields. For each request header field F, Squid uses the first
5862 qualifying sets of request_header_access rules:
5864 1. Rules with header_name equal to F's name.
5865 2. Rules with header_name 'Other', provided F's name is not
5866 on the hard-coded list of commonly used HTTP header names.
5867 3. Rules with header_name 'All'.
5869 Within that qualifying rule set, rule ACLs are checked as usual.
5870 If ACLs of an "allow" rule match, the header field is allowed to
5871 go through as is. If ACLs of a "deny" rule match, the header is
5872 removed and request_header_replace is then checked to identify
5873 if the removed header has a replacement. If no rules within the
5874 set have matching ACLs, the header field is left as is.
5876 For example, to achieve the same behavior as the old
5877 'http_anonymizer standard' option, you should use:
5879 request_header_access From deny all
5880 request_header_access Referer deny all
5881 request_header_access User-Agent deny all
5883 Or, to reproduce the old 'http_anonymizer paranoid' feature
5886 request_header_access Authorization allow all
5887 request_header_access Proxy-Authorization allow all
5888 request_header_access Cache-Control allow all
5889 request_header_access Content-Length allow all
5890 request_header_access Content-Type allow all
5891 request_header_access Date allow all
5892 request_header_access Host allow all
5893 request_header_access If-Modified-Since allow all
5894 request_header_access Pragma allow all
5895 request_header_access Accept allow all
5896 request_header_access Accept-Charset allow all
5897 request_header_access Accept-Encoding allow all
5898 request_header_access Accept-Language allow all
5899 request_header_access Connection allow all
5900 request_header_access All deny all
5902 HTTP reply headers are controlled with the reply_header_access directive.
5904 By default, all headers are allowed (no anonymizing is performed).
5907 NAME: reply_header_access
5908 IFDEF: USE_HTTP_VIOLATIONS
5909 TYPE: http_header_access
5910 LOC: Config.reply_header_access
5912 DEFAULT_DOC: No limits.
5914 Usage: reply_header_access header_name allow|deny [!]aclname ...
5916 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5917 this feature could make you liable for problems which it
5920 This option only applies to reply headers, i.e., from the
5921 server to the client.
5923 This is the same as request_header_access, but in the other
5924 direction. Please see request_header_access for detailed
5927 For example, to achieve the same behavior as the old
5928 'http_anonymizer standard' option, you should use:
5930 reply_header_access Server deny all
5931 reply_header_access WWW-Authenticate deny all
5932 reply_header_access Link deny all
5934 Or, to reproduce the old 'http_anonymizer paranoid' feature
5937 reply_header_access Allow allow all
5938 reply_header_access WWW-Authenticate allow all
5939 reply_header_access Proxy-Authenticate allow all
5940 reply_header_access Cache-Control allow all
5941 reply_header_access Content-Encoding allow all
5942 reply_header_access Content-Length allow all
5943 reply_header_access Content-Type allow all
5944 reply_header_access Date allow all
5945 reply_header_access Expires allow all
5946 reply_header_access Last-Modified allow all
5947 reply_header_access Location allow all
5948 reply_header_access Pragma allow all
5949 reply_header_access Content-Language allow all
5950 reply_header_access Retry-After allow all
5951 reply_header_access Title allow all
5952 reply_header_access Content-Disposition allow all
5953 reply_header_access Connection allow all
5954 reply_header_access All deny all
5956 HTTP request headers are controlled with the request_header_access directive.
5958 By default, all headers are allowed (no anonymizing is
5962 NAME: request_header_replace header_replace
5963 IFDEF: USE_HTTP_VIOLATIONS
5964 TYPE: http_header_replace
5965 LOC: Config.request_header_access
5968 Usage: request_header_replace header_name message
5969 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
5971 This option allows you to change the contents of headers
5972 denied with request_header_access above, by replacing them
5973 with some fixed string.
5975 This only applies to request headers, not reply headers.
5977 By default, headers are removed if denied.
5980 NAME: reply_header_replace
5981 IFDEF: USE_HTTP_VIOLATIONS
5982 TYPE: http_header_replace
5983 LOC: Config.reply_header_access
5986 Usage: reply_header_replace header_name message
5987 Example: reply_header_replace Server Foo/1.0
5989 This option allows you to change the contents of headers
5990 denied with reply_header_access above, by replacing them
5991 with some fixed string.
5993 This only applies to reply headers, not request headers.
5995 By default, headers are removed if denied.
5998 NAME: request_header_add
5999 TYPE: HeaderWithAclList
6000 LOC: Config.request_header_add
6003 Usage: request_header_add field-name field-value acl1 [acl2] ...
6004 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
6006 This option adds header fields to outgoing HTTP requests (i.e.,
6007 request headers sent by Squid to the next HTTP hop such as a
6008 cache peer or an origin server). The option has no effect during
6009 cache hit detection. The equivalent adaptation vectoring point
6010 in ICAP terminology is post-cache REQMOD.
6012 Field-name is a token specifying an HTTP header name. If a
6013 standard HTTP header name is used, Squid does not check whether
6014 the new header conflicts with any existing headers or violates
6015 HTTP rules. If the request to be modified already contains a
6016 field with the same name, the old field is preserved but the
6017 header field values are not merged.
6019 Field-value is either a token or a quoted string. If quoted
6020 string format is used, then the surrounding quotes are removed
6021 while escape sequences and %macros are processed.
6023 In theory, all of the logformat codes can be used as %macros.
6024 However, unlike logging (which happens at the very end of
6025 transaction lifetime), the transaction may not yet have enough
6026 information to expand a macro when the new header value is needed.
6027 And some information may already be available to Squid but not yet
6028 committed where the macro expansion code can access it (report
6029 such instances!). The macro will be expanded into a single dash
6030 ('-') in such cases. Not all macros have been tested.
6032 One or more Squid ACLs may be specified to restrict header
6033 injection to matching requests. As always in squid.conf, all
6034 ACLs in an option ACL list must be satisfied for the insertion
6035 to happen. The request_header_add option supports fast ACLs
6044 This option used to log custom information about the master
6045 transaction. For example, an admin may configure Squid to log
6046 which "user group" the transaction belongs to, where "user group"
6047 will be determined based on a set of ACLs and not [just]
6048 authentication information.
6049 Values of key/value pairs can be logged using %{key}note macros:
6051 note key value acl ...
6052 logformat myFormat ... %{key}note ...
6055 NAME: relaxed_header_parser
6056 COMMENT: on|off|warn
6058 LOC: Config.onoff.relaxed_header_parser
6061 In the default "on" setting Squid accepts certain forms
6062 of non-compliant HTTP messages where it is unambiguous
6063 what the sending application intended even if the message
6064 is not correctly formatted. The messages is then normalized
6065 to the correct form when forwarded by Squid.
6067 If set to "warn" then a warning will be emitted in cache.log
6068 each time such HTTP error is encountered.
6070 If set to "off" then such HTTP errors will cause the request
6071 or response to be rejected.
6074 NAME: collapsed_forwarding
6077 LOC: Config.onoff.collapsed_forwarding
6080 This option controls whether Squid is allowed to merge multiple
6081 potentially cachable requests for the same URI before Squid knows
6082 whether the response is going to be cachable.
6084 This feature is disabled by default: Enabling collapsed forwarding
6085 needlessly delays forwarding requests that look cachable (when they are
6086 collapsed) but then need to be forwarded individually anyway because
6087 they end up being for uncachable content. However, in some cases, such
6088 as accelleration of highly cachable content with periodic or groupped
6089 expiration times, the gains from collapsing [large volumes of
6090 simultenous refresh requests] outweigh losses from such delays.
6095 -----------------------------------------------------------------------------
6098 NAME: forward_timeout
6101 LOC: Config.Timeout.forward
6104 This parameter specifies how long Squid should at most attempt in
6105 finding a forwarding path for the request before giving up.
6108 NAME: connect_timeout
6111 LOC: Config.Timeout.connect
6114 This parameter specifies how long to wait for the TCP connect to
6115 the requested server or peer to complete before Squid should
6116 attempt to find another path where to forward the request.
6119 NAME: peer_connect_timeout
6122 LOC: Config.Timeout.peer_connect
6125 This parameter specifies how long to wait for a pending TCP
6126 connection to a peer cache. The default is 30 seconds. You
6127 may also set different timeout values for individual neighbors
6128 with the 'connect-timeout' option on a 'cache_peer' line.
6134 LOC: Config.Timeout.read
6137 Applied on peer server connections.
6139 After each successful read(), the timeout will be extended by this
6140 amount. If no data is read again after this amount of time,
6141 the request is aborted and logged with ERR_READ_TIMEOUT.
6143 The default is 15 minutes.
6149 LOC: Config.Timeout.write
6152 This timeout is tracked for all connections that have data
6153 available for writing and are waiting for the socket to become
6154 ready. After each successful write, the timeout is extended by
6155 the configured amount. If Squid has data to write but the
6156 connection is not ready for the configured duration, the
6157 transaction associated with the connection is terminated. The
6158 default is 15 minutes.
6161 NAME: request_timeout
6163 LOC: Config.Timeout.request
6166 How long to wait for complete HTTP request headers after initial
6167 connection establishment.
6170 NAME: request_start_timeout
6172 LOC: Config.Timeout.request_start_timeout
6175 How long to wait for the first request byte after initial
6176 connection establishment.
6179 NAME: client_idle_pconn_timeout persistent_request_timeout
6181 LOC: Config.Timeout.clientIdlePconn
6184 How long to wait for the next HTTP request on a persistent
6185 client connection after the previous request completes.
6188 NAME: ftp_client_idle_timeout
6190 LOC: Config.Timeout.ftpClientIdle
6193 How long to wait for an FTP request on a connection to Squid ftp_port.
6194 Many FTP clients do not deal with idle connection closures well,
6195 necessitating a longer default timeout than client_idle_pconn_timeout
6196 used for incoming HTTP requests.
6199 NAME: client_lifetime
6202 LOC: Config.Timeout.lifetime
6205 The maximum amount of time a client (browser) is allowed to
6206 remain connected to the cache process. This protects the Cache
6207 from having a lot of sockets (and hence file descriptors) tied up
6208 in a CLOSE_WAIT state from remote clients that go away without
6209 properly shutting down (either because of a network failure or
6210 because of a poor client implementation). The default is one
6213 NOTE: The default value is intended to be much larger than any
6214 client would ever need to be connected to your cache. You
6215 should probably change client_lifetime only as a last resort.
6216 If you seem to have many client connections tying up
6217 filedescriptors, we recommend first tuning the read_timeout,
6218 request_timeout, persistent_request_timeout and quick_abort values.
6221 NAME: pconn_lifetime
6224 LOC: Config.Timeout.pconnLifetime
6227 Desired maximum lifetime of a persistent connection.
6228 When set, Squid will close a now-idle persistent connection that
6229 exceeded configured lifetime instead of moving the connection into
6230 the idle connection pool (or equivalent). No effect on ongoing/active
6231 transactions. Connection lifetime is the time period from the
6232 connection acceptance or opening time until "now".
6234 This limit is useful in environments with long-lived connections
6235 where Squid configuration or environmental factors change during a
6236 single connection lifetime. If unrestricted, some connections may
6237 last for hours and even days, ignoring those changes that should
6238 have affected their behavior or their existence.
6240 Currently, a new lifetime value supplied via Squid reconfiguration
6241 has no effect on already idle connections unless they become busy.
6243 When set to '0' this limit is not used.
6246 NAME: half_closed_clients
6248 LOC: Config.onoff.half_closed_clients
6251 Some clients may shutdown the sending side of their TCP
6252 connections, while leaving their receiving sides open. Sometimes,
6253 Squid can not tell the difference between a half-closed and a
6254 fully-closed TCP connection.
6256 By default, Squid will immediately close client connections when
6257 read(2) returns "no more data to read."
6259 Change this option to 'on' and Squid will keep open connections
6260 until a read(2) or write(2) on the socket returns an error.
6261 This may show some benefits for reverse proxies. But if not
6262 it is recommended to leave OFF.
6265 NAME: server_idle_pconn_timeout pconn_timeout
6267 LOC: Config.Timeout.serverIdlePconn
6270 Timeout for idle persistent connections to servers and other
6277 LOC: Ident::TheConfig.timeout
6280 Maximum time to wait for IDENT lookups to complete.
6282 If this is too high, and you enabled IDENT lookups from untrusted
6283 users, you might be susceptible to denial-of-service by having
6284 many ident requests going at once.
6287 NAME: shutdown_lifetime
6290 LOC: Config.shutdownLifetime
6293 When SIGTERM or SIGHUP is received, the cache is put into
6294 "shutdown pending" mode until all active sockets are closed.
6295 This value is the lifetime to set for all open descriptors
6296 during shutdown mode. Any active clients after this many
6297 seconds will receive a 'timeout' message.
6301 ADMINISTRATIVE PARAMETERS
6302 -----------------------------------------------------------------------------
6308 LOC: Config.adminEmail
6310 Email-address of local cache manager who will receive
6311 mail if the cache dies. The default is "webmaster".
6317 LOC: Config.EmailFrom
6319 From: email-address for mail sent when the cache dies.
6320 The default is to use 'squid@unique_hostname'.
6322 See also: unique_hostname directive.
6328 LOC: Config.EmailProgram
6330 Email program used to send mail if the cache dies.
6331 The default is "mail". The specified program must comply
6332 with the standard Unix mail syntax:
6333 mail-program recipient < mailfile
6335 Optional command line options can be specified.
6338 NAME: cache_effective_user
6340 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
6341 LOC: Config.effectiveUser
6343 If you start Squid as root, it will change its effective/real
6344 UID/GID to the user specified below. The default is to change
6345 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
6346 see also; cache_effective_group
6349 NAME: cache_effective_group
6352 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
6353 LOC: Config.effectiveGroup
6355 Squid sets the GID to the effective user's default group ID
6356 (taken from the password file) and supplementary group list
6357 from the groups membership.
6359 If you want Squid to run with a specific GID regardless of
6360 the group memberships of the effective user then set this
6361 to the group (or GID) you want Squid to run as. When set
6362 all other group privileges of the effective user are ignored
6363 and only this GID is effective. If Squid is not started as
6364 root the user starting Squid MUST be member of the specified
6367 This option is not recommended by the Squid Team.
6368 Our preference is for administrators to configure a secure
6369 user account for squid with UID/GID matching system policies.
6372 NAME: httpd_suppress_version_string
6376 LOC: Config.onoff.httpd_suppress_version_string
6378 Suppress Squid version string info in HTTP headers and HTML error pages.
6381 NAME: visible_hostname
6383 LOC: Config.visibleHostname
6385 DEFAULT_DOC: Automatically detect the system host name
6387 If you want to present a special hostname in error messages, etc,
6388 define this. Otherwise, the return value of gethostname()
6389 will be used. If you have multiple caches in a cluster and
6390 get errors about IP-forwarding you must set them to have individual
6391 names with this setting.
6394 NAME: unique_hostname
6396 LOC: Config.uniqueHostname
6398 DEFAULT_DOC: Copy the value from visible_hostname
6400 If you want to have multiple machines with the same
6401 'visible_hostname' you must give each machine a different
6402 'unique_hostname' so forwarding loops can be detected.
6405 NAME: hostname_aliases
6407 LOC: Config.hostnameAliases
6410 A list of other DNS names your cache has.
6418 Minimum umask which should be enforced while the proxy
6419 is running, in addition to the umask set at startup.
6421 For a traditional octal representation of umasks, start
6426 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6427 -----------------------------------------------------------------------------
6429 This section contains parameters for the (optional) cache
6430 announcement service. This service is provided to help
6431 cache administrators locate one another in order to join or
6432 create cache hierarchies.
6434 An 'announcement' message is sent (via UDP) to the registration
6435 service by Squid. By default, the announcement message is NOT
6436 SENT unless you enable it with 'announce_period' below.
6438 The announcement message includes your hostname, plus the
6439 following information from this configuration file:
6445 All current information is processed regularly and made
6446 available on the Web at http://www.ircache.net/Cache/Tracker/.
6449 NAME: announce_period
6451 LOC: Config.Announce.period
6453 DEFAULT_DOC: Announcement messages disabled.
6455 This is how frequently to send cache announcements.
6457 To enable announcing your cache, just set an announce period.
6460 announce_period 1 day
6465 DEFAULT: tracker.ircache.net
6466 LOC: Config.Announce.host
6468 Set the hostname where announce registration messages will be sent.
6470 See also announce_port and announce_file
6476 LOC: Config.Announce.file
6478 The contents of this file will be included in the announce
6479 registration messages.
6485 LOC: Config.Announce.port
6487 Set the port where announce registration messages will be sent.
6489 See also announce_host and announce_file
6493 HTTPD-ACCELERATOR OPTIONS
6494 -----------------------------------------------------------------------------
6497 NAME: httpd_accel_surrogate_id
6500 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
6501 LOC: Config.Accel.surrogate_id
6503 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
6504 need an identification token to allow control targeting. Because
6505 a farm of surrogates may all perform the same tasks, they may share
6506 an identification token.
6509 NAME: http_accel_surrogate_remote
6513 LOC: Config.onoff.surrogate_is_remote
6515 Remote surrogates (such as those in a CDN) honour the header
6516 "Surrogate-Control: no-store-remote".
6518 Set this to on to have squid behave as a remote surrogate.
6522 IFDEF: USE_SQUID_ESI
6523 COMMENT: libxml2|expat|custom
6525 LOC: ESIParser::Type
6528 ESI markup is not strictly XML compatible. The custom ESI parser
6529 will give higher performance, but cannot handle non ASCII character
6534 DELAY POOL PARAMETERS
6535 -----------------------------------------------------------------------------
6539 TYPE: delay_pool_count
6541 IFDEF: USE_DELAY_POOLS
6544 This represents the number of delay pools to be used. For example,
6545 if you have one class 2 delay pool and one class 3 delays pool, you
6546 have a total of 2 delay pools.
6548 See also delay_parameters, delay_class, delay_access for pool
6549 configuration details.
6553 TYPE: delay_pool_class
6555 IFDEF: USE_DELAY_POOLS
6558 This defines the class of each delay pool. There must be exactly one
6559 delay_class line for each delay pool. For example, to define two
6560 delay pools, one of class 2 and one of class 3, the settings above
6564 delay_pools 4 # 4 delay pools
6565 delay_class 1 2 # pool 1 is a class 2 pool
6566 delay_class 2 3 # pool 2 is a class 3 pool
6567 delay_class 3 4 # pool 3 is a class 4 pool
6568 delay_class 4 5 # pool 4 is a class 5 pool
6570 The delay pool classes are:
6572 class 1 Everything is limited by a single aggregate
6575 class 2 Everything is limited by a single aggregate
6576 bucket as well as an "individual" bucket chosen
6577 from bits 25 through 32 of the IPv4 address.
6579 class 3 Everything is limited by a single aggregate
6580 bucket as well as a "network" bucket chosen
6581 from bits 17 through 24 of the IP address and a
6582 "individual" bucket chosen from bits 17 through
6583 32 of the IPv4 address.
6585 class 4 Everything in a class 3 delay pool, with an
6586 additional limit on a per user basis. This
6587 only takes effect if the username is established
6588 in advance - by forcing authentication in your
6591 class 5 Requests are grouped according their tag (see
6592 external_acl's tag= reply).
6595 Each pool also requires a delay_parameters directive to configure the pool size
6596 and speed limits used whenever the pool is applied to a request. Along with
6597 a set of delay_access directives to determine when it is used.
6599 NOTE: If an IP address is a.b.c.d
6600 -> bits 25 through 32 are "d"
6601 -> bits 17 through 24 are "c"
6602 -> bits 17 through 32 are "c * 256 + d"
6604 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6605 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6607 This clause only supports fast acl types.
6608 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6610 See also delay_parameters and delay_access.
6614 TYPE: delay_pool_access
6616 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6617 IFDEF: USE_DELAY_POOLS
6620 This is used to determine which delay pool a request falls into.
6622 delay_access is sorted per pool and the matching starts with pool 1,
6623 then pool 2, ..., and finally pool N. The first delay pool where the
6624 request is allowed is selected for the request. If it does not allow
6625 the request to any pool then the request is not delayed (default).
6627 For example, if you want some_big_clients in delay
6628 pool 1 and lotsa_little_clients in delay pool 2:
6630 delay_access 1 allow some_big_clients
6631 delay_access 1 deny all
6632 delay_access 2 allow lotsa_little_clients
6633 delay_access 2 deny all
6634 delay_access 3 allow authenticated_clients
6636 See also delay_parameters and delay_class.
6640 NAME: delay_parameters
6641 TYPE: delay_pool_rates
6643 IFDEF: USE_DELAY_POOLS
6646 This defines the parameters for a delay pool. Each delay pool has
6647 a number of "buckets" associated with it, as explained in the
6648 description of delay_class.
6650 For a class 1 delay pool, the syntax is:
6652 delay_parameters pool aggregate
6654 For a class 2 delay pool:
6656 delay_parameters pool aggregate individual
6658 For a class 3 delay pool:
6660 delay_parameters pool aggregate network individual
6662 For a class 4 delay pool:
6664 delay_parameters pool aggregate network individual user
6666 For a class 5 delay pool:
6668 delay_parameters pool tagrate
6670 The option variables are:
6672 pool a pool number - ie, a number between 1 and the
6673 number specified in delay_pools as used in
6676 aggregate the speed limit parameters for the aggregate bucket
6679 individual the speed limit parameters for the individual
6680 buckets (class 2, 3).
6682 network the speed limit parameters for the network buckets
6685 user the speed limit parameters for the user buckets
6688 tagrate the speed limit parameters for the tag buckets
6691 A pair of delay parameters is written restore/maximum, where restore is
6692 the number of bytes (not bits - modem and network speeds are usually
6693 quoted in bits) per second placed into the bucket, and maximum is the
6694 maximum number of bytes which can be in the bucket at any time.
6696 There must be one delay_parameters line for each delay pool.
6699 For example, if delay pool number 1 is a class 2 delay pool as in the
6700 above example, and is being used to strictly limit each host to 64Kbit/sec
6701 (plus overheads), with no overall limit, the line is:
6703 delay_parameters 1 none 8000/8000
6705 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
6707 Note that the word 'none' is used to represent no limit.
6710 And, if delay pool number 2 is a class 3 delay pool as in the above
6711 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6712 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6713 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6714 to permit a decent web page to be downloaded at a decent speed
6715 (if the network is not being limited due to overuse) but slow down
6716 large downloads more significantly:
6718 delay_parameters 2 32000/32000 8000/8000 600/8000
6720 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
6721 8 x 8000 KByte/sec -> 64Kbit/sec.
6722 8 x 600 Byte/sec -> 4800bit/sec.
6725 Finally, for a class 4 delay pool as in the example - each user will
6726 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6728 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6731 See also delay_class and delay_access.
6735 NAME: delay_initial_bucket_level
6736 COMMENT: (percent, 0-100)
6739 IFDEF: USE_DELAY_POOLS
6740 LOC: Config.Delay.initial
6742 The initial bucket percentage is used to determine how much is put
6743 in each bucket when squid starts, is reconfigured, or first notices
6744 a host accessing it (in class 2 and class 3, individual hosts and
6745 networks only have buckets associated with them once they have been
6750 CLIENT DELAY POOL PARAMETERS
6751 -----------------------------------------------------------------------------
6754 NAME: client_delay_pools
6755 TYPE: client_delay_pool_count
6757 IFDEF: USE_DELAY_POOLS
6758 LOC: Config.ClientDelay
6760 This option specifies the number of client delay pools used. It must
6761 preceed other client_delay_* options.
6764 client_delay_pools 2
6766 See also client_delay_parameters and client_delay_access.
6769 NAME: client_delay_initial_bucket_level
6770 COMMENT: (percent, 0-no_limit)
6773 IFDEF: USE_DELAY_POOLS
6774 LOC: Config.ClientDelay.initial
6776 This option determines the initial bucket size as a percentage of
6777 max_bucket_size from client_delay_parameters. Buckets are created
6778 at the time of the "first" connection from the matching IP. Idle
6779 buckets are periodically deleted up.
6781 You can specify more than 100 percent but note that such "oversized"
6782 buckets are not refilled until their size goes down to max_bucket_size
6783 from client_delay_parameters.
6786 client_delay_initial_bucket_level 50
6789 NAME: client_delay_parameters
6790 TYPE: client_delay_pool_rates
6792 IFDEF: USE_DELAY_POOLS
6793 LOC: Config.ClientDelay
6796 This option configures client-side bandwidth limits using the
6799 client_delay_parameters pool speed_limit max_bucket_size
6801 pool is an integer ID used for client_delay_access matching.
6803 speed_limit is bytes added to the bucket per second.
6805 max_bucket_size is the maximum size of a bucket, enforced after any
6806 speed_limit additions.
6808 Please see the delay_parameters option for more information and
6812 client_delay_parameters 1 1024 2048
6813 client_delay_parameters 2 51200 16384
6815 See also client_delay_access.
6819 NAME: client_delay_access
6820 TYPE: client_delay_pool_access
6822 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6823 IFDEF: USE_DELAY_POOLS
6824 LOC: Config.ClientDelay
6826 This option determines the client-side delay pool for the
6829 client_delay_access pool_ID allow|deny acl_name
6831 All client_delay_access options are checked in their pool ID
6832 order, starting with pool 1. The first checked pool with allowed
6833 request is selected for the request. If no ACL matches or there
6834 are no client_delay_access options, the request bandwidth is not
6837 The ACL-selected pool is then used to find the
6838 client_delay_parameters for the request. Client-side pools are
6839 not used to aggregate clients. Clients are always aggregated
6840 based on their source IP addresses (one bucket per source IP).
6842 This clause only supports fast acl types.
6843 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6844 Additionally, only the client TCP connection details are available.
6845 ACLs testing HTTP properties will not work.
6847 Please see delay_access for more examples.
6850 client_delay_access 1 allow low_rate_network
6851 client_delay_access 2 allow vips_network
6854 See also client_delay_parameters and client_delay_pools.
6858 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6859 -----------------------------------------------------------------------------
6864 LOC: Config.Wccp.router
6866 DEFAULT_DOC: WCCP disabled.
6869 Use this option to define your WCCP ``home'' router for
6872 wccp_router supports a single WCCP(v1) router
6874 wccp2_router supports multiple WCCPv2 routers
6876 only one of the two may be used at the same time and defines
6877 which version of WCCP to use.
6881 TYPE: IpAddress_list
6882 LOC: Config.Wccp2.router
6884 DEFAULT_DOC: WCCPv2 disabled.
6887 Use this option to define your WCCP ``home'' router for
6890 wccp_router supports a single WCCP(v1) router
6892 wccp2_router supports multiple WCCPv2 routers
6894 only one of the two may be used at the same time and defines
6895 which version of WCCP to use.
6900 LOC: Config.Wccp.version
6904 This directive is only relevant if you need to set up WCCP(v1)
6905 to some very old and end-of-life Cisco routers. In all other
6906 setups it must be left unset or at the default setting.
6907 It defines an internal version in the WCCP(v1) protocol,
6908 with version 4 being the officially documented protocol.
6910 According to some users, Cisco IOS 11.2 and earlier only
6911 support WCCP version 3. If you're using that or an earlier
6912 version of IOS, you may need to change this value to 3, otherwise
6913 do not specify this parameter.
6916 NAME: wccp2_rebuild_wait
6918 LOC: Config.Wccp2.rebuildwait
6922 If this is enabled Squid will wait for the cache dir rebuild to finish
6923 before sending the first wccp2 HereIAm packet
6926 NAME: wccp2_forwarding_method
6928 LOC: Config.Wccp2.forwarding_method
6932 WCCP2 allows the setting of forwarding methods between the
6933 router/switch and the cache. Valid values are as follows:
6935 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6936 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6938 Currently (as of IOS 12.4) cisco routers only support GRE.
6939 Cisco switches only support the L2 redirect assignment method.
6942 NAME: wccp2_return_method
6944 LOC: Config.Wccp2.return_method
6948 WCCP2 allows the setting of return methods between the
6949 router/switch and the cache for packets that the cache
6950 decides not to handle. Valid values are as follows:
6952 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6953 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6955 Currently (as of IOS 12.4) cisco routers only support GRE.
6956 Cisco switches only support the L2 redirect assignment.
6958 If the "ip wccp redirect exclude in" command has been
6959 enabled on the cache interface, then it is still safe for
6960 the proxy server to use a l2 redirect method even if this
6961 option is set to GRE.
6964 NAME: wccp2_assignment_method
6966 LOC: Config.Wccp2.assignment_method
6970 WCCP2 allows the setting of methods to assign the WCCP hash
6971 Valid values are as follows:
6973 hash - Hash assignment
6974 mask - Mask assignment
6976 As a general rule, cisco routers support the hash assignment method
6977 and cisco switches support the mask assignment method.
6982 LOC: Config.Wccp2.info
6983 DEFAULT_IF_NONE: standard 0
6984 DEFAULT_DOC: Use the 'web-cache' standard service.
6987 WCCP2 allows for multiple traffic services. There are two
6988 types: "standard" and "dynamic". The standard type defines
6989 one service id - http (id 0). The dynamic service ids can be from
6990 51 to 255 inclusive. In order to use a dynamic service id
6991 one must define the type of traffic to be redirected; this is done
6992 using the wccp2_service_info option.
6994 The "standard" type does not require a wccp2_service_info option,
6995 just specifying the service id will suffice.
6997 MD5 service authentication can be enabled by adding
6998 "password=<password>" to the end of this service declaration.
7002 wccp2_service standard 0 # for the 'web-cache' standard service
7003 wccp2_service dynamic 80 # a dynamic service type which will be
7004 # fleshed out with subsequent options.
7005 wccp2_service standard 0 password=foo
7008 NAME: wccp2_service_info
7009 TYPE: wccp2_service_info
7010 LOC: Config.Wccp2.info
7014 Dynamic WCCPv2 services require further information to define the
7015 traffic you wish to have diverted.
7019 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
7020 priority=<priority> ports=<port>,<port>..
7022 The relevant WCCPv2 flags:
7023 + src_ip_hash, dst_ip_hash
7024 + source_port_hash, dst_port_hash
7025 + src_ip_alt_hash, dst_ip_alt_hash
7026 + src_port_alt_hash, dst_port_alt_hash
7029 The port list can be one to eight entries.
7033 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
7034 priority=240 ports=80
7036 Note: the service id must have been defined by a previous
7037 'wccp2_service dynamic <id>' entry.
7042 LOC: Config.Wccp2.weight
7046 Each cache server gets assigned a set of the destination
7047 hash proportional to their weight.
7052 LOC: Config.Wccp.address
7054 DEFAULT_DOC: Address selected by the operating system.
7057 Use this option if you require WCCPv2 to use a specific
7060 The default behavior is to not bind to any specific address.
7065 LOC: Config.Wccp2.address
7067 DEFAULT_DOC: Address selected by the operating system.
7070 Use this option if you require WCCP to use a specific
7073 The default behavior is to not bind to any specific address.
7077 PERSISTENT CONNECTION HANDLING
7078 -----------------------------------------------------------------------------
7080 Also see "pconn_timeout" in the TIMEOUTS section
7083 NAME: client_persistent_connections
7085 LOC: Config.onoff.client_pconns
7088 Persistent connection support for clients.
7089 Squid uses persistent connections (when allowed). You can use
7090 this option to disable persistent connections with clients.
7093 NAME: server_persistent_connections
7095 LOC: Config.onoff.server_pconns
7098 Persistent connection support for servers.
7099 Squid uses persistent connections (when allowed). You can use
7100 this option to disable persistent connections with servers.
7103 NAME: persistent_connection_after_error
7105 LOC: Config.onoff.error_pconns
7108 With this directive the use of persistent connections after
7109 HTTP errors can be disabled. Useful if you have clients
7110 who fail to handle errors on persistent connections proper.
7113 NAME: detect_broken_pconn
7115 LOC: Config.onoff.detect_broken_server_pconns
7118 Some servers have been found to incorrectly signal the use
7119 of HTTP/1.0 persistent connections even on replies not
7120 compatible, causing significant delays. This server problem
7121 has mostly been seen on redirects.
7123 By enabling this directive Squid attempts to detect such
7124 broken replies and automatically assume the reply is finished
7125 after 10 seconds timeout.
7129 CACHE DIGEST OPTIONS
7130 -----------------------------------------------------------------------------
7133 NAME: digest_generation
7134 IFDEF: USE_CACHE_DIGESTS
7136 LOC: Config.onoff.digest_generation
7139 This controls whether the server will generate a Cache Digest
7140 of its contents. By default, Cache Digest generation is
7141 enabled if Squid is compiled with --enable-cache-digests defined.
7144 NAME: digest_bits_per_entry
7145 IFDEF: USE_CACHE_DIGESTS
7147 LOC: Config.digest.bits_per_entry
7150 This is the number of bits of the server's Cache Digest which
7151 will be associated with the Digest entry for a given HTTP
7152 Method and URL (public key) combination. The default is 5.
7155 NAME: digest_rebuild_period
7156 IFDEF: USE_CACHE_DIGESTS
7159 LOC: Config.digest.rebuild_period
7162 This is the wait time between Cache Digest rebuilds.
7165 NAME: digest_rewrite_period
7167 IFDEF: USE_CACHE_DIGESTS
7169 LOC: Config.digest.rewrite_period
7172 This is the wait time between Cache Digest writes to
7176 NAME: digest_swapout_chunk_size
7179 IFDEF: USE_CACHE_DIGESTS
7180 LOC: Config.digest.swapout_chunk_size
7183 This is the number of bytes of the Cache Digest to write to
7184 disk at a time. It defaults to 4096 bytes (4KB), the Squid
7188 NAME: digest_rebuild_chunk_percentage
7189 COMMENT: (percent, 0-100)
7190 IFDEF: USE_CACHE_DIGESTS
7192 LOC: Config.digest.rebuild_chunk_percentage
7195 This is the percentage of the Cache Digest to be scanned at a
7196 time. By default it is set to 10% of the Cache Digest.
7201 -----------------------------------------------------------------------------
7206 LOC: Config.Port.snmp
7208 DEFAULT_DOC: SNMP disabled.
7211 The port number where Squid listens for SNMP requests. To enable
7212 SNMP support set this to a suitable port number. Port number
7213 3401 is often used for the Squid SNMP agent. By default it's
7214 set to "0" (disabled)
7222 LOC: Config.accessList.snmp
7224 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
7227 Allowing or denying access to the SNMP port.
7229 All access to the agent is denied by default.
7232 snmp_access allow|deny [!]aclname ...
7234 This clause only supports fast acl types.
7235 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7238 snmp_access allow snmppublic localhost
7239 snmp_access deny all
7242 NAME: snmp_incoming_address
7244 LOC: Config.Addrs.snmp_incoming
7246 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
7249 Just like 'udp_incoming_address', but for the SNMP port.
7251 snmp_incoming_address is used for the SNMP socket receiving
7252 messages from SNMP agents.
7254 The default snmp_incoming_address is to listen on all
7255 available network interfaces.
7258 NAME: snmp_outgoing_address
7260 LOC: Config.Addrs.snmp_outgoing
7262 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
7265 Just like 'udp_outgoing_address', but for the SNMP port.
7267 snmp_outgoing_address is used for SNMP packets returned to SNMP
7270 If snmp_outgoing_address is not set it will use the same socket
7271 as snmp_incoming_address. Only change this if you want to have
7272 SNMP replies sent using another address than where this Squid
7273 listens for SNMP queries.
7275 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
7276 the same value since they both use the same port.
7281 -----------------------------------------------------------------------------
7284 NAME: icp_port udp_port
7287 DEFAULT_DOC: ICP disabled.
7288 LOC: Config.Port.icp
7290 The port number where Squid sends and receives ICP queries to
7291 and from neighbor caches. The standard UDP port for ICP is 3130.
7294 icp_port @DEFAULT_ICP_PORT@
7301 DEFAULT_DOC: HTCP disabled.
7302 LOC: Config.Port.htcp
7304 The port number where Squid sends and receives HTCP queries to
7305 and from neighbor caches. To turn it on you want to set it to
7312 NAME: log_icp_queries
7316 LOC: Config.onoff.log_udp
7318 If set, ICP queries are logged to access.log. You may wish
7319 do disable this if your ICP load is VERY high to speed things
7320 up or to simplify log analysis.
7323 NAME: udp_incoming_address
7325 LOC:Config.Addrs.udp_incoming
7327 DEFAULT_DOC: Accept packets from all machine interfaces.
7329 udp_incoming_address is used for UDP packets received from other
7332 The default behavior is to not bind to any specific address.
7334 Only change this if you want to have all UDP queries received on
7335 a specific interface/address.
7337 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
7338 modules. Altering it will affect all of them in the same manner.
7340 see also; udp_outgoing_address
7342 NOTE, udp_incoming_address and udp_outgoing_address can not
7343 have the same value since they both use the same port.
7346 NAME: udp_outgoing_address
7348 LOC: Config.Addrs.udp_outgoing
7350 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
7352 udp_outgoing_address is used for UDP packets sent out to other
7355 The default behavior is to not bind to any specific address.
7357 Instead it will use the same socket as udp_incoming_address.
7358 Only change this if you want to have UDP queries sent using another
7359 address than where this Squid listens for UDP queries from other
7362 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7363 modules. Altering it will affect all of them in the same manner.
7365 see also; udp_incoming_address
7367 NOTE, udp_incoming_address and udp_outgoing_address can not
7368 have the same value since they both use the same port.
7375 LOC: Config.onoff.icp_hit_stale
7377 If you want to return ICP_HIT for stale cache objects, set this
7378 option to 'on'. If you have sibling relationships with caches
7379 in other administrative domains, this should be 'off'. If you only
7380 have sibling relationships with caches under your control,
7381 it is probably okay to set this to 'on'.
7382 If set to 'on', your siblings should use the option "allow-miss"
7383 on their cache_peer lines for connecting to you.
7386 NAME: minimum_direct_hops
7389 LOC: Config.minDirectHops
7391 If using the ICMP pinging stuff, do direct fetches for sites
7392 which are no more than this many hops away.
7395 NAME: minimum_direct_rtt
7399 LOC: Config.minDirectRtt
7401 If using the ICMP pinging stuff, do direct fetches for sites
7402 which are no more than this many rtt milliseconds away.
7408 LOC: Config.Netdb.low
7410 The low water mark for the ICMP measurement database.
7412 Note: high watermark controlled by netdb_high directive.
7414 These watermarks are counts, not percents. The defaults are
7415 (low) 900 and (high) 1000. When the high water mark is
7416 reached, database entries will be deleted until the low
7423 LOC: Config.Netdb.high
7425 The high water mark for the ICMP measurement database.
7427 Note: low watermark controlled by netdb_low directive.
7429 These watermarks are counts, not percents. The defaults are
7430 (low) 900 and (high) 1000. When the high water mark is
7431 reached, database entries will be deleted until the low
7435 NAME: netdb_ping_period
7437 LOC: Config.Netdb.period
7440 The minimum period for measuring a site. There will be at
7441 least this much delay between successive pings to the same
7442 network. The default is five minutes.
7449 LOC: Config.onoff.query_icmp
7451 If you want to ask your peers to include ICMP data in their ICP
7452 replies, enable this option.
7454 If your peer has configured Squid (during compilation) with
7455 '--enable-icmp' that peer will send ICMP pings to origin server
7456 sites of the URLs it receives. If you enable this option the
7457 ICP replies from that peer will include the ICMP data (if available).
7458 Then, when choosing a parent cache, Squid will choose the parent with
7459 the minimal RTT to the origin server. When this happens, the
7460 hierarchy field of the access.log will be
7461 "CLOSEST_PARENT_MISS". This option is off by default.
7464 NAME: test_reachability
7468 LOC: Config.onoff.test_reachability
7470 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
7471 instead of ICP_MISS if the target host is NOT in the ICMP
7472 database, or has a zero RTT.
7475 NAME: icp_query_timeout
7478 DEFAULT_DOC: Dynamic detection.
7480 LOC: Config.Timeout.icp_query
7482 Normally Squid will automatically determine an optimal ICP
7483 query timeout value based on the round-trip-time of recent ICP
7484 queries. If you want to override the value determined by
7485 Squid, set this 'icp_query_timeout' to a non-zero value. This
7486 value is specified in MILLISECONDS, so, to use a 2-second
7487 timeout (the old default), you would write:
7489 icp_query_timeout 2000
7492 NAME: maximum_icp_query_timeout
7496 LOC: Config.Timeout.icp_query_max
7498 Normally the ICP query timeout is determined dynamically. But
7499 sometimes it can lead to very large values (say 5 seconds).
7500 Use this option to put an upper limit on the dynamic timeout
7501 value. Do NOT use this option to always use a fixed (instead
7502 of a dynamic) timeout value. To set a fixed timeout see the
7503 'icp_query_timeout' directive.
7506 NAME: minimum_icp_query_timeout
7510 LOC: Config.Timeout.icp_query_min
7512 Normally the ICP query timeout is determined dynamically. But
7513 sometimes it can lead to very small timeouts, even lower than
7514 the normal latency variance on your link due to traffic.
7515 Use this option to put an lower limit on the dynamic timeout
7516 value. Do NOT use this option to always use a fixed (instead
7517 of a dynamic) timeout value. To set a fixed timeout see the
7518 'icp_query_timeout' directive.
7521 NAME: background_ping_rate
7525 LOC: Config.backgroundPingRate
7527 Controls how often the ICP pings are sent to siblings that
7528 have background-ping set.
7532 MULTICAST ICP OPTIONS
7533 -----------------------------------------------------------------------------
7538 LOC: Config.mcast_group_list
7541 This tag specifies a list of multicast groups which your server
7542 should join to receive multicasted ICP queries.
7544 NOTE! Be very careful what you put here! Be sure you
7545 understand the difference between an ICP _query_ and an ICP
7546 _reply_. This option is to be set only if you want to RECEIVE
7547 multicast queries. Do NOT set this option to SEND multicast
7548 ICP (use cache_peer for that). ICP replies are always sent via
7549 unicast, so this option does not affect whether or not you will
7550 receive replies from multicast group members.
7552 You must be very careful to NOT use a multicast address which
7553 is already in use by another group of caches.
7555 If you are unsure about multicast, please read the Multicast
7556 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7558 Usage: mcast_groups 239.128.16.128 224.0.1.20
7560 By default, Squid doesn't listen on any multicast groups.
7563 NAME: mcast_miss_addr
7564 IFDEF: MULTICAST_MISS_STREAM
7566 LOC: Config.mcast_miss.addr
7568 DEFAULT_DOC: disabled.
7570 If you enable this option, every "cache miss" URL will
7571 be sent out on the specified multicast address.
7573 Do not enable this option unless you are are absolutely
7574 certain you understand what you are doing.
7577 NAME: mcast_miss_ttl
7578 IFDEF: MULTICAST_MISS_STREAM
7580 LOC: Config.mcast_miss.ttl
7583 This is the time-to-live value for packets multicasted
7584 when multicasting off cache miss URLs is enabled. By
7585 default this is set to 'site scope', i.e. 16.
7588 NAME: mcast_miss_port
7589 IFDEF: MULTICAST_MISS_STREAM
7591 LOC: Config.mcast_miss.port
7594 This is the port number to be used in conjunction with
7598 NAME: mcast_miss_encode_key
7599 IFDEF: MULTICAST_MISS_STREAM
7601 LOC: Config.mcast_miss.encode_key
7602 DEFAULT: XXXXXXXXXXXXXXXX
7604 The URLs that are sent in the multicast miss stream are
7605 encrypted. This is the encryption key.
7608 NAME: mcast_icp_query_timeout
7612 LOC: Config.Timeout.mcast_icp_query
7614 For multicast peers, Squid regularly sends out ICP "probes" to
7615 count how many other peers are listening on the given multicast
7616 address. This value specifies how long Squid should wait to
7617 count all the replies. The default is 2000 msec, or 2
7622 INTERNAL ICON OPTIONS
7623 -----------------------------------------------------------------------------
7626 NAME: icon_directory
7628 LOC: Config.icons.directory
7629 DEFAULT: @DEFAULT_ICON_DIR@
7631 Where the icons are stored. These are normally kept in
7635 NAME: global_internal_static
7637 LOC: Config.onoff.global_internal_static
7640 This directive controls is Squid should intercept all requests for
7641 /squid-internal-static/ no matter which host the URL is requesting
7642 (default on setting), or if nothing special should be done for
7643 such URLs (off setting). The purpose of this directive is to make
7644 icons etc work better in complex cache hierarchies where it may
7645 not always be possible for all corners in the cache mesh to reach
7646 the server generating a directory listing.
7649 NAME: short_icon_urls
7651 LOC: Config.icons.use_short_names
7654 If this is enabled Squid will use short URLs for icons.
7655 If disabled it will revert to the old behavior of including
7656 it's own name and port in the URL.
7658 If you run a complex cache hierarchy with a mix of Squid and
7659 other proxies you may need to disable this directive.
7664 -----------------------------------------------------------------------------
7667 NAME: error_directory
7669 LOC: Config.errorDirectory
7671 DEFAULT_DOC: Send error pages in the clients preferred language
7673 If you wish to create your own versions of the default
7674 error files to customize them to suit your company copy
7675 the error/template files to another directory and point
7678 WARNING: This option will disable multi-language support
7679 on error pages if used.
7681 The squid developers are interested in making squid available in
7682 a wide variety of languages. If you are making translations for a
7683 language that Squid does not currently provide please consider
7684 contributing your translation back to the project.
7685 http://wiki.squid-cache.org/Translations
7687 The squid developers working on translations are happy to supply drop-in
7688 translated error files in exchange for any new language contributions.
7691 NAME: error_default_language
7692 IFDEF: USE_ERR_LOCALES
7694 LOC: Config.errorDefaultLanguage
7696 DEFAULT_DOC: Generate English language pages.
7698 Set the default language which squid will send error pages in
7699 if no existing translation matches the clients language
7702 If unset (default) generic English will be used.
7704 The squid developers are interested in making squid available in
7705 a wide variety of languages. If you are interested in making
7706 translations for any language see the squid wiki for details.
7707 http://wiki.squid-cache.org/Translations
7710 NAME: error_log_languages
7711 IFDEF: USE_ERR_LOCALES
7713 LOC: Config.errorLogMissingLanguages
7716 Log to cache.log what languages users are attempting to
7717 auto-negotiate for translations.
7719 Successful negotiations are not logged. Only failures
7720 have meaning to indicate that Squid may need an upgrade
7721 of its error page translations.
7724 NAME: err_page_stylesheet
7726 LOC: Config.errorStylesheet
7727 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7729 CSS Stylesheet to pattern the display of Squid default error pages.
7731 For information on CSS see http://www.w3.org/Style/CSS/
7736 LOC: Config.errHtmlText
7739 HTML text to include in error messages. Make this a "mailto"
7740 URL to your admin address, or maybe just a link to your
7741 organizations Web page.
7743 To include this in your error messages, you must rewrite
7744 the error template files (found in the "errors" directory).
7745 Wherever you want the 'err_html_text' line to appear,
7746 insert a %L tag in the error template file.
7749 NAME: email_err_data
7752 LOC: Config.onoff.emailErrData
7755 If enabled, information about the occurred error will be
7756 included in the mailto links of the ERR pages (if %W is set)
7757 so that the email body contains the data.
7758 Syntax is <A HREF="mailto:%w%W">%w</A>
7763 LOC: Config.denyInfoList
7766 Usage: deny_info err_page_name acl
7767 or deny_info http://... acl
7768 or deny_info TCP_RESET acl
7770 This can be used to return a ERR_ page for requests which
7771 do not pass the 'http_access' rules. Squid remembers the last
7772 acl it evaluated in http_access, and if a 'deny_info' line exists
7773 for that ACL Squid returns a corresponding error page.
7775 The acl is typically the last acl on the http_access deny line which
7776 denied access. The exceptions to this rule are:
7777 - When Squid needs to request authentication credentials. It's then
7778 the first authentication related acl encountered
7779 - When none of the http_access lines matches. It's then the last
7780 acl processed on the last http_access line.
7781 - When the decision to deny access was made by an adaptation service,
7782 the acl name is the corresponding eCAP or ICAP service_name.
7784 NP: If providing your own custom error pages with error_directory
7785 you may also specify them by your custom file name:
7786 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7788 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7789 may be specified by prefixing the file name with the code and a colon.
7790 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7792 Alternatively you can tell Squid to reset the TCP connection
7793 by specifying TCP_RESET.
7795 Or you can specify an error URL or URL pattern. The browsers will
7796 get redirected to the specified URL after formatting tags have
7797 been replaced. Redirect will be done with 302 or 307 according to
7798 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7799 the URL. e.g. 303:http://example.com/
7802 %a - username (if available. Password NOT included)
7805 %E - Error description
7807 %H - Request domain name
7808 %i - Client IP Address
7810 %o - Message result from external ACL helper
7811 %p - Request Port number
7812 %P - Request Protocol name
7813 %R - Request URL path
7814 %T - Timestamp in RFC 1123 format
7815 %U - Full canonical URL from client
7816 (HTTPS URLs terminate with *)
7817 %u - Full canonical URL from client
7818 %w - Admin email from squid.conf
7820 %% - Literal percent (%) code
7825 OPTIONS INFLUENCING REQUEST FORWARDING
7826 -----------------------------------------------------------------------------
7829 NAME: nonhierarchical_direct
7831 LOC: Config.onoff.nonhierarchical_direct
7834 By default, Squid will send any non-hierarchical requests
7835 (not cacheable request type) direct to origin servers.
7837 When this is set to "off", Squid will prefer to send these
7838 requests to parents.
7840 Note that in most configurations, by turning this off you will only
7841 add latency to these request without any improvement in global hit
7844 This option only sets a preference. If the parent is unavailable a
7845 direct connection to the origin server may still be attempted. To
7846 completely prevent direct connections use never_direct.
7851 LOC: Config.onoff.prefer_direct
7854 Normally Squid tries to use parents for most requests. If you for some
7855 reason like it to first try going direct and only use a parent if
7856 going direct fails set this to on.
7858 By combining nonhierarchical_direct off and prefer_direct on you
7859 can set up Squid to use a parent as a backup path if going direct
7862 Note: If you want Squid to use parents for all requests see
7863 the never_direct directive. prefer_direct only modifies how Squid
7864 acts on cacheable requests.
7867 NAME: cache_miss_revalidate
7871 LOC: Config.onoff.cache_miss_revalidate
7873 RFC 7232 defines a conditional request mechanism to prevent
7874 response objects being unnecessarily transferred over the network.
7875 If that mechanism is used by the client and a cache MISS occurs
7876 it can prevent new cache entries being created.
7878 This option determines whether Squid on cache MISS will pass the
7879 client revalidation request to the server or tries to fetch new
7880 content for caching. It can be useful while the cache is mostly
7881 empty to more quickly have the cache populated by generating
7882 non-conditional GETs.
7884 When set to 'on' (default), Squid will pass all client If-* headers
7885 to the server. This permits server responses without a cacheable
7886 payload to be delivered and on MISS no new cache entry is created.
7888 When set to 'off' and if the request is cacheable, Squid will
7889 remove the clients If-Modified-Since and If-None-Match headers from
7890 the request sent to the server. This requests a 200 status response
7891 from the server to create a new cache entry with.
7896 LOC: Config.accessList.AlwaysDirect
7898 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7900 Usage: always_direct allow|deny [!]aclname ...
7902 Here you can use ACL elements to specify requests which should
7903 ALWAYS be forwarded by Squid to the origin servers without using
7904 any peers. For example, to always directly forward requests for
7905 local servers ignoring any parents or siblings you may have use
7908 acl local-servers dstdomain my.domain.net
7909 always_direct allow local-servers
7911 To always forward FTP requests directly, use
7914 always_direct allow FTP
7916 NOTE: There is a similar, but opposite option named
7917 'never_direct'. You need to be aware that "always_direct deny
7918 foo" is NOT the same thing as "never_direct allow foo". You
7919 may need to use a deny rule to exclude a more-specific case of
7920 some other rule. Example:
7922 acl local-external dstdomain external.foo.net
7923 acl local-servers dstdomain .foo.net
7924 always_direct deny local-external
7925 always_direct allow local-servers
7927 NOTE: If your goal is to make the client forward the request
7928 directly to the origin server bypassing Squid then this needs
7929 to be done in the client configuration. Squid configuration
7930 can only tell Squid how Squid should fetch the object.
7932 NOTE: This directive is not related to caching. The replies
7933 is cached as usual even if you use always_direct. To not cache
7934 the replies see the 'cache' directive.
7936 This clause supports both fast and slow acl types.
7937 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7942 LOC: Config.accessList.NeverDirect
7944 DEFAULT_DOC: Allow DNS results to be used for this request.
7946 Usage: never_direct allow|deny [!]aclname ...
7948 never_direct is the opposite of always_direct. Please read
7949 the description for always_direct if you have not already.
7951 With 'never_direct' you can use ACL elements to specify
7952 requests which should NEVER be forwarded directly to origin
7953 servers. For example, to force the use of a proxy for all
7954 requests, except those in your local domain use something like:
7956 acl local-servers dstdomain .foo.net
7957 never_direct deny local-servers
7958 never_direct allow all
7960 or if Squid is inside a firewall and there are local intranet
7961 servers inside the firewall use something like:
7963 acl local-intranet dstdomain .foo.net
7964 acl local-external dstdomain external.foo.net
7965 always_direct deny local-external
7966 always_direct allow local-intranet
7967 never_direct allow all
7969 This clause supports both fast and slow acl types.
7970 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7974 ADVANCED NETWORKING OPTIONS
7975 -----------------------------------------------------------------------------
7978 NAME: incoming_udp_average incoming_icp_average
7981 LOC: Config.comm_incoming.udp.average
7983 Heavy voodoo here. I can't even believe you are reading this.
7984 Are you crazy? Don't even think about adjusting these unless
7985 you understand the algorithms in comm_select.c first!
7988 NAME: incoming_tcp_average incoming_http_average
7991 LOC: Config.comm_incoming.tcp.average
7993 Heavy voodoo here. I can't even believe you are reading this.
7994 Are you crazy? Don't even think about adjusting these unless
7995 you understand the algorithms in comm_select.c first!
7998 NAME: incoming_dns_average
8001 LOC: Config.comm_incoming.dns.average
8003 Heavy voodoo here. I can't even believe you are reading this.
8004 Are you crazy? Don't even think about adjusting these unless
8005 you understand the algorithms in comm_select.c first!
8008 NAME: min_udp_poll_cnt min_icp_poll_cnt
8011 LOC: Config.comm_incoming.udp.min_poll
8013 Heavy voodoo here. I can't even believe you are reading this.
8014 Are you crazy? Don't even think about adjusting these unless
8015 you understand the algorithms in comm_select.c first!
8018 NAME: min_dns_poll_cnt
8021 LOC: Config.comm_incoming.dns.min_poll
8023 Heavy voodoo here. I can't even believe you are reading this.
8024 Are you crazy? Don't even think about adjusting these unless
8025 you understand the algorithms in comm_select.c first!
8028 NAME: min_tcp_poll_cnt min_http_poll_cnt
8031 LOC: Config.comm_incoming.tcp.min_poll
8033 Heavy voodoo here. I can't even believe you are reading this.
8034 Are you crazy? Don't even think about adjusting these unless
8035 you understand the algorithms in comm_select.c first!
8041 LOC: Config.accept_filter
8045 The name of an accept(2) filter to install on Squid's
8046 listen socket(s). This feature is perhaps specific to
8047 FreeBSD and requires support in the kernel.
8049 The 'httpready' filter delays delivering new connections
8050 to Squid until a full HTTP request has been received.
8051 See the accf_http(9) man page for details.
8053 The 'dataready' filter delays delivering new connections
8054 to Squid until there is some data to process.
8055 See the accf_dataready(9) man page for details.
8059 The 'data' filter delays delivering of new connections
8060 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
8061 You may optionally specify a number of seconds to wait by
8062 'data=N' where N is the number of seconds. Defaults to 30
8063 if not specified. See the tcp(7) man page for details.
8066 accept_filter httpready
8071 NAME: client_ip_max_connections
8073 LOC: Config.client_ip_max_connections
8075 DEFAULT_DOC: No limit.
8077 Set an absolute limit on the number of connections a single
8078 client IP can use. Any more than this and Squid will begin to drop
8079 new connections from the client until it closes some links.
8081 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
8082 connections from the client. For finer control use the ACL access controls.
8084 Requires client_db to be enabled (the default).
8086 WARNING: This may noticably slow down traffic received via external proxies
8087 or NAT devices and cause them to rebound error messages back to their clients.
8090 NAME: tcp_recv_bufsize
8094 DEFAULT_DOC: Use operating system TCP defaults.
8095 LOC: Config.tcpRcvBufsz
8097 Size of receive buffer to set for TCP sockets. Probably just
8098 as easy to change your kernel's default.
8099 Omit from squid.conf to use the default buffer size.
8104 -----------------------------------------------------------------------------
8111 LOC: Adaptation::Icap::TheConfig.onoff
8114 If you want to enable the ICAP module support, set this to on.
8117 NAME: icap_connect_timeout
8120 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
8123 This parameter specifies how long to wait for the TCP connect to
8124 the requested ICAP server to complete before giving up and either
8125 terminating the HTTP transaction or bypassing the failure.
8127 The default for optional services is peer_connect_timeout.
8128 The default for essential services is connect_timeout.
8129 If this option is explicitly set, its value applies to all services.
8132 NAME: icap_io_timeout
8136 DEFAULT_DOC: Use read_timeout.
8137 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
8140 This parameter specifies how long to wait for an I/O activity on
8141 an established, active ICAP connection before giving up and
8142 either terminating the HTTP transaction or bypassing the
8146 NAME: icap_service_failure_limit
8147 COMMENT: limit [in memory-depth time-units]
8148 TYPE: icap_service_failure_limit
8150 LOC: Adaptation::Icap::TheConfig
8153 The limit specifies the number of failures that Squid tolerates
8154 when establishing a new TCP connection with an ICAP service. If
8155 the number of failures exceeds the limit, the ICAP service is
8156 not used for new ICAP requests until it is time to refresh its
8159 A negative value disables the limit. Without the limit, an ICAP
8160 service will not be considered down due to connectivity failures
8161 between ICAP OPTIONS requests.
8163 Squid forgets ICAP service failures older than the specified
8164 value of memory-depth. The memory fading algorithm
8165 is approximate because Squid does not remember individual
8166 errors but groups them instead, splitting the option
8167 value into ten time slots of equal length.
8169 When memory-depth is 0 and by default this option has no
8170 effect on service failure expiration.
8172 Squid always forgets failures when updating service settings
8173 using an ICAP OPTIONS transaction, regardless of this option
8177 # suspend service usage after 10 failures in 5 seconds:
8178 icap_service_failure_limit 10 in 5 seconds
8181 NAME: icap_service_revival_delay
8184 LOC: Adaptation::Icap::TheConfig.service_revival_delay
8187 The delay specifies the number of seconds to wait after an ICAP
8188 OPTIONS request failure before requesting the options again. The
8189 failed ICAP service is considered "down" until fresh OPTIONS are
8192 The actual delay cannot be smaller than the hardcoded minimum
8193 delay of 30 seconds.
8196 NAME: icap_preview_enable
8200 LOC: Adaptation::Icap::TheConfig.preview_enable
8203 The ICAP Preview feature allows the ICAP server to handle the
8204 HTTP message by looking only at the beginning of the message body
8205 or even without receiving the body at all. In some environments,
8206 previews greatly speedup ICAP processing.
8208 During an ICAP OPTIONS transaction, the server may tell Squid what
8209 HTTP messages should be previewed and how big the preview should be.
8210 Squid will not use Preview if the server did not request one.
8212 To disable ICAP Preview for all ICAP services, regardless of
8213 individual ICAP server OPTIONS responses, set this option to "off".
8215 icap_preview_enable off
8218 NAME: icap_preview_size
8221 LOC: Adaptation::Icap::TheConfig.preview_size
8223 DEFAULT_DOC: No preview sent.
8225 The default size of preview data to be sent to the ICAP server.
8226 This value might be overwritten on a per server basis by OPTIONS requests.
8229 NAME: icap_206_enable
8233 LOC: Adaptation::Icap::TheConfig.allow206_enable
8236 206 (Partial Content) responses is an ICAP extension that allows the
8237 ICAP agents to optionally combine adapted and original HTTP message
8238 content. The decision to combine is postponed until the end of the
8239 ICAP response. Squid supports Partial Content extension by default.
8241 Activation of the Partial Content extension is negotiated with each
8242 ICAP service during OPTIONS exchange. Most ICAP servers should handle
8243 negotation correctly even if they do not support the extension, but
8244 some might fail. To disable Partial Content support for all ICAP
8245 services and to avoid any negotiation, set this option to "off".
8251 NAME: icap_default_options_ttl
8254 LOC: Adaptation::Icap::TheConfig.default_options_ttl
8257 The default TTL value for ICAP OPTIONS responses that don't have
8258 an Options-TTL header.
8261 NAME: icap_persistent_connections
8265 LOC: Adaptation::Icap::TheConfig.reuse_connections
8268 Whether or not Squid should use persistent connections to
8272 NAME: adaptation_send_client_ip icap_send_client_ip
8274 IFDEF: USE_ADAPTATION
8276 LOC: Adaptation::Config::send_client_ip
8279 If enabled, Squid shares HTTP client IP information with adaptation
8280 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
8281 For eCAP, Squid sets the libecap::metaClientIp transaction option.
8283 See also: adaptation_uses_indirect_client
8286 NAME: adaptation_send_username icap_send_client_username
8288 IFDEF: USE_ADAPTATION
8290 LOC: Adaptation::Config::send_username
8293 This sends authenticated HTTP client username (if available) to
8294 the adaptation service.
8296 For ICAP, the username value is encoded based on the
8297 icap_client_username_encode option and is sent using the header
8298 specified by the icap_client_username_header option.
8301 NAME: icap_client_username_header
8304 LOC: Adaptation::Icap::TheConfig.client_username_header
8305 DEFAULT: X-Client-Username
8307 ICAP request header name to use for adaptation_send_username.
8310 NAME: icap_client_username_encode
8314 LOC: Adaptation::Icap::TheConfig.client_username_encode
8317 Whether to base64 encode the authenticated client username.
8321 TYPE: icap_service_type
8323 LOC: Adaptation::Icap::TheConfig
8326 Defines a single ICAP service using the following format:
8328 icap_service id vectoring_point uri [option ...]
8331 an opaque identifier or name which is used to direct traffic to
8332 this specific service. Must be unique among all adaptation
8333 services in squid.conf.
8335 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8336 This specifies at which point of transaction processing the
8337 ICAP service should be activated. *_postcache vectoring points
8338 are not yet supported.
8340 uri: icap://servername:port/servicepath
8341 ICAP server and service location.
8343 ICAP does not allow a single service to handle both REQMOD and RESPMOD
8344 transactions. Squid does not enforce that requirement. You can specify
8345 services with the same service_url and different vectoring_points. You
8346 can even specify multiple identical services as long as their
8347 service_names differ.
8349 To activate a service, use the adaptation_access directive. To group
8350 services, use adaptation_service_chain and adaptation_service_set.
8352 Service options are separated by white space. ICAP services support
8353 the following name=value options:
8356 If set to 'on' or '1', the ICAP service is treated as
8357 optional. If the service cannot be reached or malfunctions,
8358 Squid will try to ignore any errors and process the message as
8359 if the service was not enabled. No all ICAP errors can be
8360 bypassed. If set to 0, the ICAP service is treated as
8361 essential and all ICAP errors will result in an error page
8362 returned to the HTTP client.
8364 Bypass is off by default: services are treated as essential.
8367 If set to 'on' or '1', the ICAP service is allowed to
8368 dynamically change the current message adaptation plan by
8369 returning a chain of services to be used next. The services
8370 are specified using the X-Next-Services ICAP response header
8371 value, formatted as a comma-separated list of service names.
8372 Each named service should be configured in squid.conf. Other
8373 services are ignored. An empty X-Next-Services value results
8374 in an empty plan which ends the current adaptation.
8376 Dynamic adaptation plan may cross or cover multiple supported
8377 vectoring points in their natural processing order.
8379 Routing is not allowed by default: the ICAP X-Next-Services
8380 response header is ignored.
8383 Only has effect on split-stack systems. The default on those systems
8384 is to use IPv4-only connections. When set to 'on' this option will
8385 make Squid use IPv6-only connections to contact this ICAP service.
8387 on-overload=block|bypass|wait|force
8388 If the service Max-Connections limit has been reached, do
8389 one of the following for each new ICAP transaction:
8390 * block: send an HTTP error response to the client
8391 * bypass: ignore the "over-connected" ICAP service
8392 * wait: wait (in a FIFO queue) for an ICAP connection slot
8393 * force: proceed, ignoring the Max-Connections limit
8395 In SMP mode with N workers, each worker assumes the service
8396 connection limit is Max-Connections/N, even though not all
8397 workers may use a given service.
8399 The default value is "bypass" if service is bypassable,
8400 otherwise it is set to "wait".
8404 Use the given number as the Max-Connections limit, regardless
8405 of the Max-Connections value given by the service, if any.
8407 Older icap_service format without optional named parameters is
8408 deprecated but supported for backward compatibility.
8411 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
8412 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
8416 TYPE: icap_class_type
8421 This deprecated option was documented to define an ICAP service
8422 chain, even though it actually defined a set of similar, redundant
8423 services, and the chains were not supported.
8425 To define a set of redundant services, please use the
8426 adaptation_service_set directive. For service chains, use
8427 adaptation_service_chain.
8431 TYPE: icap_access_type
8436 This option is deprecated. Please use adaptation_access, which
8437 has the same ICAP functionality, but comes with better
8438 documentation, and eCAP support.
8443 -----------------------------------------------------------------------------
8450 LOC: Adaptation::Ecap::TheConfig.onoff
8453 Controls whether eCAP support is enabled.
8457 TYPE: ecap_service_type
8459 LOC: Adaptation::Ecap::TheConfig
8462 Defines a single eCAP service
8464 ecap_service id vectoring_point uri [option ...]
8467 an opaque identifier or name which is used to direct traffic to
8468 this specific service. Must be unique among all adaptation
8469 services in squid.conf.
8471 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8472 This specifies at which point of transaction processing the
8473 eCAP service should be activated. *_postcache vectoring points
8474 are not yet supported.
8476 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
8477 Squid uses the eCAP service URI to match this configuration
8478 line with one of the dynamically loaded services. Each loaded
8479 eCAP service must have a unique URI. Obtain the right URI from
8480 the service provider.
8482 To activate a service, use the adaptation_access directive. To group
8483 services, use adaptation_service_chain and adaptation_service_set.
8485 Service options are separated by white space. eCAP services support
8486 the following name=value options:
8489 If set to 'on' or '1', the eCAP service is treated as optional.
8490 If the service cannot be reached or malfunctions, Squid will try
8491 to ignore any errors and process the message as if the service
8492 was not enabled. No all eCAP errors can be bypassed.
8493 If set to 'off' or '0', the eCAP service is treated as essential
8494 and all eCAP errors will result in an error page returned to the
8497 Bypass is off by default: services are treated as essential.
8500 If set to 'on' or '1', the eCAP service is allowed to
8501 dynamically change the current message adaptation plan by
8502 returning a chain of services to be used next.
8504 Dynamic adaptation plan may cross or cover multiple supported
8505 vectoring points in their natural processing order.
8507 Routing is not allowed by default.
8509 Older ecap_service format without optional named parameters is
8510 deprecated but supported for backward compatibility.
8514 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
8515 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
8518 NAME: loadable_modules
8520 IFDEF: USE_LOADABLE_MODULES
8521 LOC: Config.loadable_module_names
8524 Instructs Squid to load the specified dynamic module(s) or activate
8525 preloaded module(s).
8527 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
8531 MESSAGE ADAPTATION OPTIONS
8532 -----------------------------------------------------------------------------
8535 NAME: adaptation_service_set
8536 TYPE: adaptation_service_set_type
8537 IFDEF: USE_ADAPTATION
8542 Configures an ordered set of similar, redundant services. This is
8543 useful when hot standby or backup adaptation servers are available.
8545 adaptation_service_set set_name service_name1 service_name2 ...
8547 The named services are used in the set declaration order. The first
8548 applicable adaptation service from the set is used first. The next
8549 applicable service is tried if and only if the transaction with the
8550 previous service fails and the message waiting to be adapted is still
8553 When adaptation starts, broken services are ignored as if they were
8554 not a part of the set. A broken service is a down optional service.
8556 The services in a set must be attached to the same vectoring point
8557 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8559 If all services in a set are optional then adaptation failures are
8560 bypassable. If all services in the set are essential, then a
8561 transaction failure with one service may still be retried using
8562 another service from the set, but when all services fail, the master
8563 transaction fails as well.
8565 A set may contain a mix of optional and essential services, but that
8566 is likely to lead to surprising results because broken services become
8567 ignored (see above), making previously bypassable failures fatal.
8568 Technically, it is the bypassability of the last failed service that
8571 See also: adaptation_access adaptation_service_chain
8574 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
8575 adaptation service_set svcLogger loggerLocal loggerRemote
8578 NAME: adaptation_service_chain
8579 TYPE: adaptation_service_chain_type
8580 IFDEF: USE_ADAPTATION
8585 Configures a list of complementary services that will be applied
8586 one-by-one, forming an adaptation chain or pipeline. This is useful
8587 when Squid must perform different adaptations on the same message.
8589 adaptation_service_chain chain_name service_name1 svc_name2 ...
8591 The named services are used in the chain declaration order. The first
8592 applicable adaptation service from the chain is used first. The next
8593 applicable service is applied to the successful adaptation results of
8594 the previous service in the chain.
8596 When adaptation starts, broken services are ignored as if they were
8597 not a part of the chain. A broken service is a down optional service.
8599 Request satisfaction terminates the adaptation chain because Squid
8600 does not currently allow declaration of RESPMOD services at the
8601 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8603 The services in a chain must be attached to the same vectoring point
8604 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8606 A chain may contain a mix of optional and essential services. If an
8607 essential adaptation fails (or the failure cannot be bypassed for
8608 other reasons), the master transaction fails. Otherwise, the failure
8609 is bypassed as if the failed adaptation service was not in the chain.
8611 See also: adaptation_access adaptation_service_set
8614 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8617 NAME: adaptation_access
8618 TYPE: adaptation_access_type
8619 IFDEF: USE_ADAPTATION
8622 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8624 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8626 adaptation_access service_name allow|deny [!]aclname...
8627 adaptation_access set_name allow|deny [!]aclname...
8629 At each supported vectoring point, the adaptation_access
8630 statements are processed in the order they appear in this
8631 configuration file. Statements pointing to the following services
8632 are ignored (i.e., skipped without checking their ACL):
8634 - services serving different vectoring points
8635 - "broken-but-bypassable" services
8636 - "up" services configured to ignore such transactions
8637 (e.g., based on the ICAP Transfer-Ignore header).
8639 When a set_name is used, all services in the set are checked
8640 using the same rules, to find the first applicable one. See
8641 adaptation_service_set for details.
8643 If an access list is checked and there is a match, the
8644 processing stops: For an "allow" rule, the corresponding
8645 adaptation service is used for the transaction. For a "deny"
8646 rule, no adaptation service is activated.
8648 It is currently not possible to apply more than one adaptation
8649 service at the same vectoring point to the same HTTP transaction.
8651 See also: icap_service and ecap_service
8654 adaptation_access service_1 allow all
8657 NAME: adaptation_service_iteration_limit
8659 IFDEF: USE_ADAPTATION
8660 LOC: Adaptation::Config::service_iteration_limit
8663 Limits the number of iterations allowed when applying adaptation
8664 services to a message. If your longest adaptation set or chain
8665 may have more than 16 services, increase the limit beyond its
8666 default value of 16. If detecting infinite iteration loops sooner
8667 is critical, make the iteration limit match the actual number
8668 of services in your longest adaptation set or chain.
8670 Infinite adaptation loops are most likely with routing services.
8672 See also: icap_service routing=1
8675 NAME: adaptation_masterx_shared_names
8677 IFDEF: USE_ADAPTATION
8678 LOC: Adaptation::Config::masterx_shared_name
8681 For each master transaction (i.e., the HTTP request and response
8682 sequence, including all related ICAP and eCAP exchanges), Squid
8683 maintains a table of metadata. The table entries are (name, value)
8684 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8685 with the master transaction.
8687 This option specifies the table entry names that Squid must accept
8688 from and forward to the adaptation transactions.
8690 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8691 shared table by returning an ICAP header field with a name
8692 specified in adaptation_masterx_shared_names.
8694 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8695 shared table by implementing the libecap::visitEachOption() API
8696 to provide an option with a name specified in
8697 adaptation_masterx_shared_names.
8699 Squid will store and forward the set entry to subsequent adaptation
8700 transactions within the same master transaction scope.
8702 Only one shared entry name is supported at this time.
8705 # share authentication information among ICAP services
8706 adaptation_masterx_shared_names X-Subscriber-ID
8709 NAME: adaptation_meta
8711 IFDEF: USE_ADAPTATION
8712 LOC: Adaptation::Config::metaHeaders
8715 This option allows Squid administrator to add custom ICAP request
8716 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8717 Use it to pass custom authentication tokens and other
8718 transaction-state related meta information to an ICAP/eCAP service.
8720 The addition of a meta header is ACL-driven:
8721 adaptation_meta name value [!]aclname ...
8723 Processing for a given header name stops after the first ACL list match.
8724 Thus, it is impossible to add two headers with the same name. If no ACL
8725 lists match for a given header name, no such header is added. For
8728 # do not debug transactions except for those that need debugging
8729 adaptation_meta X-Debug 1 needs_debugging
8731 # log all transactions except for those that must remain secret
8732 adaptation_meta X-Log 1 !keep_secret
8734 # mark transactions from users in the "G 1" group
8735 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8737 The "value" parameter may be a regular squid.conf token or a "double
8738 quoted string". Within the quoted string, use backslash (\) to escape
8739 any character, which is currently only useful for escaping backslashes
8740 and double quotes. For example,
8741 "this string has one backslash (\\) and two \"quotes\""
8743 Used adaptation_meta header values may be logged via %note
8744 logformat code. If multiple adaptation_meta headers with the same name
8745 are used during master transaction lifetime, the header values are
8746 logged in the order they were used and duplicate values are ignored
8747 (only the first repeated value will be logged).
8753 LOC: Adaptation::Icap::TheConfig.repeat
8754 DEFAULT_IF_NONE: deny all
8756 This ACL determines which retriable ICAP transactions are
8757 retried. Transactions that received a complete ICAP response
8758 and did not have to consume or produce HTTP bodies to receive
8759 that response are usually retriable.
8761 icap_retry allow|deny [!]aclname ...
8763 Squid automatically retries some ICAP I/O timeouts and errors
8764 due to persistent connection race conditions.
8766 See also: icap_retry_limit
8769 NAME: icap_retry_limit
8772 LOC: Adaptation::Icap::TheConfig.repeat_limit
8774 DEFAULT_DOC: No retries are allowed.
8776 Limits the number of retries allowed.
8778 Communication errors due to persistent connection race
8779 conditions are unavoidable, automatically retried, and do not
8780 count against this limit.
8782 See also: icap_retry
8788 -----------------------------------------------------------------------------
8791 NAME: check_hostnames
8794 LOC: Config.onoff.check_hostnames
8796 For security and stability reasons Squid can check
8797 hostnames for Internet standard RFC compliance. If you want
8798 Squid to perform these checks turn this directive on.
8801 NAME: allow_underscore
8804 LOC: Config.onoff.allow_underscore
8806 Underscore characters is not strictly allowed in Internet hostnames
8807 but nevertheless used by many sites. Set this to off if you want
8808 Squid to be strict about the standard.
8809 This check is performed only when check_hostnames is set to on.
8812 NAME: dns_retransmit_interval
8815 LOC: Config.Timeout.idns_retransmit
8817 Initial retransmit interval for DNS queries. The interval is
8818 doubled each time all configured DNS servers have been tried.
8824 LOC: Config.Timeout.idns_query
8826 DNS Query timeout. If no response is received to a DNS query
8827 within this time all DNS servers for the queried domain
8828 are assumed to be unavailable.
8831 NAME: dns_packet_max
8833 DEFAULT_DOC: EDNS disabled
8835 LOC: Config.dns.packet_max
8837 Maximum number of bytes packet size to advertise via EDNS.
8838 Set to "none" to disable EDNS large packet support.
8840 For legacy reasons DNS UDP replies will default to 512 bytes which
8841 is too small for many responses. EDNS provides a means for Squid to
8842 negotiate receiving larger responses back immediately without having
8843 to failover with repeat requests. Responses larger than this limit
8844 will retain the old behaviour of failover to TCP DNS.
8846 Squid has no real fixed limit internally, but allowing packet sizes
8847 over 1500 bytes requires network jumbogram support and is usually not
8850 WARNING: The RFC also indicates that some older resolvers will reply
8851 with failure of the whole request if the extension is added. Some
8852 resolvers have already been identified which will reply with mangled
8853 EDNS response on occasion. Usually in response to many-KB jumbogram
8854 sizes being advertised by Squid.
8855 Squid will currently treat these both as an unable-to-resolve domain
8856 even if it would be resolvable without EDNS.
8863 DEFAULT_DOC: Search for single-label domain names is disabled.
8864 LOC: Config.onoff.res_defnames
8866 Normally the RES_DEFNAMES resolver option is disabled
8867 (see res_init(3)). This prevents caches in a hierarchy
8868 from interpreting single-component hostnames locally. To allow
8869 Squid to handle single-component names, enable this option.
8872 NAME: dns_multicast_local
8876 DEFAULT_DOC: Search for .local and .arpa names is disabled.
8877 LOC: Config.onoff.dns_mdns
8879 When set to on, Squid sends multicast DNS lookups on the local
8880 network for domains ending in .local and .arpa.
8881 This enables local servers and devices to be contacted in an
8882 ad-hoc or zero-configuration network environment.
8885 NAME: dns_nameservers
8888 DEFAULT_DOC: Use operating system definitions
8889 LOC: Config.dns_nameservers
8891 Use this if you want to specify a list of DNS name servers
8892 (IP addresses) to use instead of those given in your
8893 /etc/resolv.conf file.
8895 On Windows platforms, if no value is specified here or in
8896 the /etc/resolv.conf file, the list of DNS name servers are
8897 taken from the Windows registry, both static and dynamic DHCP
8898 configurations are supported.
8900 Example: dns_nameservers 10.0.0.1 192.172.0.4
8905 DEFAULT: @DEFAULT_HOSTS@
8906 LOC: Config.etcHostsPath
8908 Location of the host-local IP name-address associations
8909 database. Most Operating Systems have such a file on different
8911 - Un*X & Linux: /etc/hosts
8912 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
8913 (%SystemRoot% value install default is c:\winnt)
8914 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
8915 (%SystemRoot% value install default is c:\windows)
8916 - Windows 9x/Me: %windir%\hosts
8917 (%windir% value is usually c:\windows)
8918 - Cygwin: /etc/hosts
8920 The file contains newline-separated definitions, in the
8921 form ip_address_in_dotted_form name [name ...] names are
8922 whitespace-separated. Lines beginning with an hash (#)
8923 character are comments.
8925 The file is checked at startup and upon configuration.
8926 If set to 'none', it won't be checked.
8927 If append_domain is used, that domain will be added to
8928 domain-local (i.e. not containing any dot character) host
8934 LOC: Config.appendDomain
8936 DEFAULT_DOC: Use operating system definitions
8938 Appends local domain name to hostnames without any dots in
8939 them. append_domain must begin with a period.
8941 Be warned there are now Internet names with no dots in
8942 them using only top-domain names, so setting this may
8943 cause some Internet sites to become unavailable.
8946 append_domain .yourdomain.com
8949 NAME: ignore_unknown_nameservers
8951 LOC: Config.onoff.ignore_unknown_nameservers
8954 By default Squid checks that DNS responses are received
8955 from the same IP addresses they are sent to. If they
8956 don't match, Squid ignores the response and writes a warning
8957 message to cache.log. You can allow responses from unknown
8958 nameservers by setting this option to 'off'.
8964 LOC: Config.dns.v4_first
8966 With the IPv6 Internet being as fast or faster than IPv4 Internet
8967 for most networks Squid prefers to contact websites over IPv6.
8969 This option reverses the order of preference to make Squid contact
8970 dual-stack websites over IPv4 first. Squid will still perform both
8971 IPv6 and IPv4 DNS lookups before connecting.
8974 This option will restrict the situations under which IPv6
8975 connectivity is used (and tested). Hiding network problems
8976 which would otherwise be detected and warned about.
8980 COMMENT: (number of entries)
8983 LOC: Config.ipcache.size
8985 Maximum number of DNS IP cache entries.
8992 LOC: Config.ipcache.low
8999 LOC: Config.ipcache.high
9001 The size, low-, and high-water marks for the IP cache.
9004 NAME: fqdncache_size
9005 COMMENT: (number of entries)
9008 LOC: Config.fqdncache.size
9010 Maximum number of FQDN cache entries.
9015 -----------------------------------------------------------------------------
9018 NAME: configuration_includes_quoted_values
9020 TYPE: configuration_includes_quoted_values
9022 LOC: ConfigParser::RecognizeQuotedValues
9024 If set, Squid will recognize each "quoted string" after a configuration
9025 directive as a single parameter. The quotes are stripped before the
9026 parameter value is interpreted or used.
9027 See "Values with spaces, quotes, and other special characters"
9028 section for more details.
9035 LOC: Config.onoff.mem_pools
9037 If set, Squid will keep pools of allocated (but unused) memory
9038 available for future use. If memory is a premium on your
9039 system and you believe your malloc library outperforms Squid
9040 routines, disable this.
9043 NAME: memory_pools_limit
9047 LOC: Config.MemPools.limit
9049 Used only with memory_pools on:
9050 memory_pools_limit 50 MB
9052 If set to a non-zero value, Squid will keep at most the specified
9053 limit of allocated (but unused) memory in memory pools. All free()
9054 requests that exceed this limit will be handled by your malloc
9055 library. Squid does not pre-allocate any memory, just safe-keeps
9056 objects that otherwise would be free()d. Thus, it is safe to set
9057 memory_pools_limit to a reasonably high value even if your
9058 configuration will use less memory.
9060 If set to none, Squid will keep all memory it can. That is, there
9061 will be no limit on the total amount of memory used for safe-keeping.
9063 To disable memory allocation optimization, do not set
9064 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
9066 An overhead for maintaining memory pools is not taken into account
9067 when the limit is checked. This overhead is close to four bytes per
9068 object kept. However, pools may actually _save_ memory because of
9069 reduced memory thrashing in your malloc library.
9073 COMMENT: on|off|transparent|truncate|delete
9076 LOC: opt_forwarded_for
9078 If set to "on", Squid will append your client's IP address
9079 in the HTTP requests it forwards. By default it looks like:
9081 X-Forwarded-For: 192.1.2.3
9083 If set to "off", it will appear as
9085 X-Forwarded-For: unknown
9087 If set to "transparent", Squid will not alter the
9088 X-Forwarded-For header in any way.
9090 If set to "delete", Squid will delete the entire
9091 X-Forwarded-For header.
9093 If set to "truncate", Squid will remove all existing
9094 X-Forwarded-For entries, and place the client IP as the sole entry.
9097 NAME: cachemgr_passwd
9098 TYPE: cachemgrpasswd
9100 DEFAULT_DOC: No password. Actions which require password are denied.
9101 LOC: Config.passwd_list
9103 Specify passwords for cachemgr operations.
9105 Usage: cachemgr_passwd password action action ...
9107 Some valid actions are (see cache manager menu for a full list):
9147 * Indicates actions which will not be performed without a
9148 valid password, others can be performed if not listed here.
9150 To disable an action, set the password to "disable".
9151 To allow performing an action without a password, set the
9154 Use the keyword "all" to set the same password for all actions.
9157 cachemgr_passwd secret shutdown
9158 cachemgr_passwd lesssssssecret info stats/objects
9159 cachemgr_passwd disable all
9166 LOC: Config.onoff.client_db
9168 If you want to disable collecting per-client statistics,
9169 turn off client_db here.
9172 NAME: refresh_all_ims
9176 LOC: Config.onoff.refresh_all_ims
9178 When you enable this option, squid will always check
9179 the origin server for an update when a client sends an
9180 If-Modified-Since request. Many browsers use IMS
9181 requests when the user requests a reload, and this
9182 ensures those clients receive the latest version.
9184 By default (off), squid may return a Not Modified response
9185 based on the age of the cached version.
9188 NAME: reload_into_ims
9189 IFDEF: USE_HTTP_VIOLATIONS
9193 LOC: Config.onoff.reload_into_ims
9195 When you enable this option, client no-cache or ``reload''
9196 requests will be changed to If-Modified-Since requests.
9197 Doing this VIOLATES the HTTP standard. Enabling this
9198 feature could make you liable for problems which it
9201 see also refresh_pattern for a more selective approach.
9204 NAME: connect_retries
9206 LOC: Config.connect_retries
9208 DEFAULT_DOC: Do not retry failed connections.
9210 This sets the maximum number of connection attempts made for each
9211 TCP connection. The connect_retries attempts must all still
9212 complete within the connection timeout period.
9214 The default is not to re-try if the first connection attempt fails.
9215 The (not recommended) maximum is 10 tries.
9217 A warning message will be generated if it is set to a too-high
9218 value and the configured value will be over-ridden.
9220 Note: These re-tries are in addition to forward_max_tries
9221 which limit how many different addresses may be tried to find
9225 NAME: retry_on_error
9227 LOC: Config.retry.onerror
9230 If set to ON Squid will automatically retry requests when
9231 receiving an error response with status 403 (Forbidden),
9232 500 (Internal Error), 501 or 503 (Service not available).
9233 Status 502 and 504 (Gateway errors) are always retried.
9235 This is mainly useful if you are in a complex cache hierarchy to
9236 work around access control errors.
9238 NOTE: This retry will attempt to find another working destination.
9239 Which is different from the server which just failed.
9242 NAME: as_whois_server
9244 LOC: Config.as_whois_server
9245 DEFAULT: whois.ra.net
9247 WHOIS server to query for AS numbers. NOTE: AS numbers are
9248 queried only when Squid starts up, not for every request.
9253 LOC: Config.onoff.offline
9256 Enable this option and Squid will never try to validate cached
9260 NAME: uri_whitespace
9261 TYPE: uri_whitespace
9262 LOC: Config.uri_whitespace
9265 What to do with requests that have whitespace characters in the
9268 strip: The whitespace characters are stripped out of the URL.
9269 This is the behavior recommended by RFC2396 and RFC3986
9270 for tolerant handling of generic URI.
9271 NOTE: This is one difference between generic URI and HTTP URLs.
9273 deny: The request is denied. The user receives an "Invalid
9275 This is the behaviour recommended by RFC2616 for safe
9276 handling of HTTP request URL.
9278 allow: The request is allowed and the URI is not changed. The
9279 whitespace characters remain in the URI. Note the
9280 whitespace is passed to redirector processes if they
9282 Note this may be considered a violation of RFC2616
9283 request parsing where whitespace is prohibited in the
9286 encode: The request is allowed and the whitespace characters are
9287 encoded according to RFC1738.
9289 chop: The request is allowed and the URI is chopped at the
9293 NOTE the current Squid implementation of encode and chop violates
9294 RFC2616 by not using a 301 redirect after altering the URL.
9299 LOC: Config.chroot_dir
9302 Specifies a directory where Squid should do a chroot() while
9303 initializing. This also causes Squid to fully drop root
9304 privileges after initializing. This means, for example, if you
9305 use a HTTP port less than 1024 and try to reconfigure, you may
9306 get an error saying that Squid can not open the port.
9309 NAME: balance_on_multiple_ip
9311 LOC: Config.onoff.balance_on_multiple_ip
9314 Modern IP resolvers in squid sort lookup results by preferred access.
9315 By default squid will use these IP in order and only rotates to
9316 the next listed when the most preffered fails.
9318 Some load balancing servers based on round robin DNS have been
9319 found not to preserve user session state across requests
9320 to different IP addresses.
9322 Enabling this directive Squid rotates IP's per request.
9325 NAME: pipeline_prefetch
9326 TYPE: pipelinePrefetch
9327 LOC: Config.pipeline_max_prefetch
9329 DEFAULT_DOC: Do not pre-parse pipelined requests.
9331 HTTP clients may send a pipeline of 1+N requests to Squid using a
9332 single connection, without waiting for Squid to respond to the first
9333 of those requests. This option limits the number of concurrent
9334 requests Squid will try to handle in parallel. If set to N, Squid
9335 will try to receive and process up to 1+N requests on the same
9336 connection concurrently.
9338 Defaults to 0 (off) for bandwidth management and access logging
9341 NOTE: pipelining requires persistent connections to clients.
9343 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
9346 NAME: high_response_time_warning
9349 LOC: Config.warnings.high_rptm
9351 DEFAULT_DOC: disabled.
9353 If the one-minute median response time exceeds this value,
9354 Squid prints a WARNING with debug level 0 to get the
9355 administrators attention. The value is in milliseconds.
9358 NAME: high_page_fault_warning
9360 LOC: Config.warnings.high_pf
9362 DEFAULT_DOC: disabled.
9364 If the one-minute average page fault rate exceeds this
9365 value, Squid prints a WARNING with debug level 0 to get
9366 the administrators attention. The value is in page faults
9370 NAME: high_memory_warning
9372 LOC: Config.warnings.high_memory
9373 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
9375 DEFAULT_DOC: disabled.
9377 If the memory usage (as determined by gnumalloc, if available and used)
9378 exceeds this amount, Squid prints a WARNING with debug level 0 to get
9379 the administrators attention.
9381 # TODO: link high_memory_warning to mempools?
9383 NAME: sleep_after_fork
9384 COMMENT: (microseconds)
9386 LOC: Config.sleep_after_fork
9389 When this is set to a non-zero value, the main Squid process
9390 sleeps the specified number of microseconds after a fork()
9391 system call. This sleep may help the situation where your
9392 system reports fork() failures due to lack of (virtual)
9393 memory. Note, however, if you have a lot of child
9394 processes, these sleep delays will add up and your
9395 Squid will not service requests for some amount of time
9396 until all the child processes have been started.
9397 On Windows value less then 1000 (1 milliseconds) are
9401 NAME: windows_ipaddrchangemonitor
9402 IFDEF: _SQUID_WINDOWS_
9406 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
9408 On Windows Squid by default will monitor IP address changes and will
9409 reconfigure itself after any detected event. This is very useful for
9410 proxies connected to internet with dial-up interfaces.
9411 In some cases (a Proxy server acting as VPN gateway is one) it could be
9412 desiderable to disable this behaviour setting this to 'off'.
9413 Note: after changing this, Squid service must be restarted.
9418 IFDEF: USE_SQUID_EUI
9420 LOC: Eui::TheConfig.euiLookup
9422 Whether to lookup the EUI or MAC address of a connected client.
9425 NAME: max_filedescriptors max_filedesc
9428 DEFAULT_DOC: Use operating system limits set by ulimit.
9429 LOC: Config.max_filedescriptors
9431 Reduce the maximum number of filedescriptors supported below
9432 the usual operating system defaults.
9434 Remove from squid.conf to inherit the current ulimit setting.
9436 Note: Changing this requires a restart of Squid. Also
9437 not all I/O types supports large values (eg on Windows).
9444 DEFAULT_DOC: SMP support disabled.
9446 Number of main Squid processes or "workers" to fork and maintain.
9447 0: "no daemon" mode, like running "squid -N ..."
9448 1: "no SMP" mode, start one main Squid process daemon (default)
9449 N: start N main Squid process daemons (i.e., SMP mode)
9451 In SMP mode, each worker does nearly all what a single Squid daemon
9452 does (e.g., listen on http_port and forward HTTP requests).
9455 NAME: cpu_affinity_map
9456 TYPE: CpuAffinityMap
9457 LOC: Config.cpuAffinityMap
9459 DEFAULT_DOC: Let operating system decide.
9461 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
9463 Sets 1:1 mapping between Squid processes and CPU cores. For example,
9465 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
9467 affects processes 1 through 4 only and places them on the first
9468 four even cores, starting with core #1.
9470 CPU cores are numbered starting from 1. Requires support for
9471 sched_getaffinity(2) and sched_setaffinity(2) system calls.
9473 Multiple cpu_affinity_map options are merged.
9478 NAME: force_request_body_continuation
9480 LOC: Config.accessList.forceRequestBodyContinuation
9482 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
9484 This option controls how Squid handles data upload requests from HTTP
9485 and FTP agents that require a "Please Continue" control message response
9486 to actually send the request body to Squid. It is mostly useful in
9487 adaptation environments.
9489 When Squid receives an HTTP request with an "Expect: 100-continue"
9490 header or an FTP upload command (e.g., STOR), Squid normally sends the
9491 request headers or FTP command information to an adaptation service (or
9492 peer) and waits for a response. Most adaptation services (and some
9493 broken peers) may not respond to Squid at that stage because they may
9494 decide to wait for the HTTP request body or FTP data transfer. However,
9495 that request body or data transfer may never come because Squid has not
9496 responded with the HTTP 100 or FTP 150 (Please Continue) control message
9497 to the request sender yet!
9499 An allow match tells Squid to respond with the HTTP 100 or FTP 150
9500 (Please Continue) control message on its own, before forwarding the
9501 request to an adaptation service or peer. Such a response usually forces
9502 the request sender to proceed with sending the body. A deny match tells
9503 Squid to delay that control response until the origin server confirms
9504 that the request body is needed. Delaying is the default behavior.
projects / thirdparty / squid.git / blob