2 # SQUID Web Proxy Cache http://www.squid-cache.org/
3 # ----------------------------------------------------------
5 # Squid is the result of efforts by numerous individuals from
6 # the Internet community; see the CONTRIBUTORS file for full
7 # details. Many organizations have provided support for Squid's
8 # development; see the SPONSORS file for full details. Squid is
9 # Copyrighted (C) 2000 by the Regents of the University of
10 # California; see the COPYRIGHT file for full details. Squid
11 # incorporates software developed and/or copyrighted by other
12 # sources; see the CREDITS file for full details.
14 # This program is free software; you can redistribute it and/or modify
15 # it under the terms of the GNU General Public License as published by
16 # the Free Software Foundation; either version 2 of the License, or
17 # (at your option) any later version.
19 # This program is distributed in the hope that it will be useful,
20 # but WITHOUT ANY WARRANTY; without even the implied warranty of
21 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 # GNU General Public License for more details.
24 # You should have received a copy of the GNU General Public License
25 # along with this program; if not, write to the Free Software
26 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
31 ----------------------------
33 This is the documentation for the Squid configuration file.
34 This documentation can also be found online at:
35 http://www.squid-cache.org/Doc/config/
37 You may wish to look at the Squid home page and wiki for the
38 FAQ and other documentation:
39 http://www.squid-cache.org/
40 http://wiki.squid-cache.org/SquidFaq
41 http://wiki.squid-cache.org/ConfigExamples
43 This documentation shows what the defaults for various directives
44 happen to be. If you don't need to change the default, you should
45 leave the line out of your squid.conf in most cases.
47 In some cases "none" refers to no default setting at all,
48 while in other cases it refers to the value of the option
49 - the comments for that keyword indicate if this is the case.
54 Configuration options can be included using the "include" directive.
55 Include takes a list of files to include. Quoting and wildcards are
60 include /path/to/included/file/squid.acl.config
62 Includes can be nested up to a hard-coded depth of 16 levels.
63 This arbitrary restriction is to prevent recursive include references
64 from causing Squid entering an infinite loop whilst trying to load
67 Values with byte units
69 Squid accepts size units on some size related directives. All
70 such directives are documented with a default value displaying
73 Units accepted by Squid are:
75 KB - Kilobyte (1024 bytes)
79 Values with spaces, quotes, and other special characters
81 Squid supports directive parameters with spaces, quotes, and other
82 special characters. Surround such parameters with "double quotes". Use
83 the configuration_includes_quoted_values directive to enable or
86 Squid supports reading configuration option parameters from external
87 files using the syntax:
88 parameters("/path/filename")
90 acl whitelist dstdomain parameters("/etc/squid/whitelist.txt")
92 Conditional configuration
94 If-statements can be used to make configuration directives
98 ... regular configuration directives ...
100 ... regular configuration directives ...]
103 The else part is optional. The keywords "if", "else", and "endif"
104 must be typed on their own lines, as if they were regular
105 configuration directives.
107 NOTE: An else-if condition is not supported.
109 These individual conditions types are supported:
112 Always evaluates to true.
114 Always evaluates to false.
115 <integer> = <integer>
116 Equality comparison of two integer numbers.
121 The following SMP-related preprocessor macros can be used.
123 ${process_name} expands to the current Squid process "name"
124 (e.g., squid1, squid2, or cache1).
126 ${process_number} expands to the current Squid process
127 identifier, which is an integer number (e.g., 1, 2, 3) unique
128 across all Squid processes of the current service instance.
130 ${service_name} expands into the current Squid service instance
131 name identifier which is provided by -n on the command line.
135 # options still not yet ported from 2.7 to 3.x
136 NAME: broken_vary_encoding
139 This option is not yet supported by Squid-3.
145 This option is not yet supported by Squid-3.
151 This option is not yet supported by Squid-3.
154 NAME: external_refresh_check
157 This option is not yet supported by Squid-3.
160 NAME: location_rewrite_program location_rewrite_access location_rewrite_children location_rewrite_concurrency
163 This option is not yet supported by Squid-3.
166 NAME: refresh_stale_hit
169 This option is not yet supported by Squid-3.
172 # Options removed in 3.5
173 NAME: hierarchy_stoplist
176 Remove this line. Use always_direct or cache_peer_access ACLs instead if you need to prevent cache_peer use.
182 Remove this line. Use acls with access_log directives to control access logging
188 Remove this line. Use acls with icap_log directives to control icap logging
191 # Options Removed in 3.3
192 NAME: ignore_ims_on_miss
195 Remove this line. The HTTP/1.1 feature is now configured by 'cache_miss_revalidate'.
198 # Options Removed in 3.2
199 NAME: dns_v4_fallback
202 Remove this line. Squid performs a 'Happy Eyeballs' algorithm, the 'fallback' algorithm is no longer relevant.
205 NAME: emulate_httpd_log
208 Replace this with an access_log directive using the format 'common' or 'combined'.
214 Use a regular access.log with ACL limiting it to MISS events.
220 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
223 NAME: ignore_expect_100
226 Remove this line. The HTTP/1.1 feature is now fully supported by default.
232 Remove this option from your config. To log FQDN use %>A in the log format.
235 NAME: log_ip_on_direct
238 Remove this option from your config. To log server or peer names use %<A in the log format.
241 NAME: maximum_single_addr_tries
244 Replaced by connect_retries. The behaviour has changed, please read the documentation before altering.
247 NAME: referer_log referrer_log
250 Replace this with an access_log directive using the format 'referrer'.
256 Remove this line. The feature is supported by default in storage types where update is implemented.
259 NAME: url_rewrite_concurrency
262 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
268 Replace this with an access_log directive using the format 'useragent'.
271 # Options Removed in 3.1
275 Remove this line. DNS is no longer tested on startup.
278 NAME: extension_methods
281 Remove this line. All valid methods for HTTP are accepted by default.
284 # 2.7 Options Removed/Replaced in 3.2
289 # 2.7 Options Removed/Replaced in 3.1
297 Remove this line. HTTP/1.1 is supported by default.
300 NAME: upgrade_http0.9
303 Remove this line. ICY/1.0 streaming protocol is supported by default.
306 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
309 Alter these entries. Use the qos_flows directive instead.
312 # Options Removed in 3.0
316 Since squid-3.0 replace with request_header_access or reply_header_access
317 depending on whether you wish to match client requests or server replies.
320 NAME: httpd_accel_no_pmtu_disc
323 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
326 NAME: wais_relay_host
329 Replace this line with 'cache_peer' configuration.
332 NAME: wais_relay_port
335 Replace this line with 'cache_peer' configuration.
339 OPTIONS FOR AUTHENTICATION
340 -----------------------------------------------------------------------------
349 This is used to define parameters for the various authentication
350 schemes supported by Squid.
352 format: auth_param scheme parameter [setting]
354 The order in which authentication schemes are presented to the client is
355 dependent on the order the scheme first appears in config file. IE
356 has a bug (it's not RFC 2617 compliant) in that it will use the basic
357 scheme if basic is the first entry presented, even if more secure
358 schemes are presented. For now use the order in the recommended
359 settings section below. If other browsers have difficulties (don't
360 recognize the schemes offered even if you are using basic) either
361 put basic first, or disable the other schemes (by commenting out their
364 Once an authentication scheme is fully configured, it can only be
365 shutdown by shutting squid down and restarting. Changes can be made on
366 the fly and activated with a reconfigure. I.E. You can change to a
367 different helper, but not unconfigure the helper completely.
369 Please note that while this directive defines how Squid processes
370 authentication it does not automatically activate authentication.
371 To use authentication you must in addition make use of ACLs based
372 on login name in http_access (proxy_auth, proxy_auth_regex or
373 external with %LOGIN used in the format tag). The browser will be
374 challenged for authentication on the first such acl encountered
375 in http_access processing and will also be re-challenged for new
376 login credentials if the request is being denied by a proxy_auth
379 WARNING: authentication can't be used in a transparently intercepting
380 proxy as the client then thinks it is talking to an origin server and
381 not the proxy. This is a limitation of bending the TCP/IP protocol to
382 transparently intercepting port 80, not a limitation in Squid.
383 Ports flagged 'transparent', 'intercept', or 'tproxy' have
384 authentication disabled.
386 === Parameters common to all schemes. ===
389 Specifies the command for the external authenticator.
391 By default, each authentication scheme is not used unless a
392 program is specified.
394 See http://wiki.squid-cache.org/Features/AddonHelpers for
395 more details on helper operations and creating your own.
398 Specifies a string to be append to request line format for
399 the authentication helper. "Quoted" format values may contain
400 spaces and logformat %macros. In theory, any logformat %macro
401 can be used. In practice, a %macro expands as a dash (-) if
402 the helper request is sent before the required macro
403 information is available to Squid.
405 By default, Squid uses request formats provided in
406 scheme-specific examples below (search for %credentials).
408 The expanded key_extras value is added to the Squid credentials
409 cache and, hence, will affect authentication. It can be used to
410 autenticate different users with identical user names (e.g.,
411 when user authentication depends on http_port).
413 Avoid adding frequently changing information to key_extras. For
414 example, if you add user source IP, and it changes frequently
415 in your environment, then max_user_ip ACL is going to treat
416 every user+IP combination as a unique "user", breaking the ACL
417 and wasting a lot of memory on those user records. It will also
418 force users to authenticate from scratch whenever their IP
422 Specifies the protection scope (aka realm name) which is to be
423 reported to the client for the authentication scheme. It is
424 commonly part of the text the user will see when prompted for
425 their username and password.
427 For Basic the default is "Squid proxy-caching web server".
428 For Digest there is no default, this parameter is mandatory.
429 For NTLM and Negotiate this parameter is ignored.
431 "children" numberofchildren [startup=N] [idle=N] [concurrency=N] [queue-size=N]
433 The maximum number of authenticator processes to spawn. If
434 you start too few Squid will have to wait for them to process
435 a backlog of credential verifications, slowing it down. When
436 password verifications are done via a (slow) network you are
437 likely to need lots of authenticator processes.
439 The startup= and idle= options permit some skew in the exact
440 amount run. A minimum of startup=N will begin during startup
441 and reconfigure. Squid will start more in groups of up to
442 idle=N in an attempt to meet traffic needs and to keep idle=N
443 free above those traffic needs up to the maximum.
445 The concurrency= option sets the number of concurrent requests
446 the helper can process. The default of 0 is used for helpers
447 who only supports one request at a time. Setting this to a
448 number greater than 0 changes the protocol used to include a
449 channel ID field first on the request/response line, allowing
450 multiple requests to be sent to the same helper in parallel
451 without waiting for the response.
453 Concurrency must not be set unless it's known the helper
454 supports the input format with channel-ID fields.
456 The queue-size= option sets the maximum number of queued
457 requests. If the queued requests exceed queue size for more
458 than 3 minutes then squid aborts its operation.
459 The default value is set to 2*numberofchildren/
461 NOTE: NTLM and Negotiate schemes do not support concurrency
462 in the Squid code module even though some helpers can.
465 IF HAVE_AUTH_MODULE_BASIC
466 === Basic authentication parameters ===
469 HTTP uses iso-latin-1 as character set, while some
470 authentication backends such as LDAP expects UTF-8. If this is
471 set to on Squid will translate the HTTP iso-latin-1 charset to
472 UTF-8 before sending the username and password to the helper.
474 "credentialsttl" timetolive
475 Specifies how long squid assumes an externally validated
476 username:password pair is valid for - in other words how
477 often the helper program is called for that user. Set this
478 low to force revalidation with short lived passwords.
480 NOTE: setting this high does not impact your susceptibility
481 to replay attacks unless you are using an one-time password
482 system (such as SecureID). If you are using such a system,
483 you will be vulnerable to replay attacks unless you also
484 use the max_user_ip ACL in an http_access rule.
486 "casesensitive" on|off
487 Specifies if usernames are case sensitive. Most user databases
488 are case insensitive allowing the same username to be spelled
489 using both lower and upper case letters, but some are case
490 sensitive. This makes a big difference for user_max_ip ACL
491 processing and similar.
494 IF HAVE_AUTH_MODULE_DIGEST
495 === Digest authentication parameters ===
498 HTTP uses iso-latin-1 as character set, while some
499 authentication backends such as LDAP expects UTF-8. If this is
500 set to on Squid will translate the HTTP iso-latin-1 charset to
501 UTF-8 before sending the username and password to the helper.
503 "nonce_garbage_interval" timeinterval
504 Specifies the interval that nonces that have been issued
505 to client_agent's are checked for validity.
507 "nonce_max_duration" timeinterval
508 Specifies the maximum length of time a given nonce will be
511 "nonce_max_count" number
512 Specifies the maximum number of times a given nonce can be
515 "nonce_strictness" on|off
516 Determines if squid requires strict increment-by-1 behavior
517 for nonce counts, or just incrementing (off - for use when
518 user agents generate nonce counts that occasionally miss 1
519 (ie, 1,2,4,6)). Default off.
521 "check_nonce_count" on|off
522 This directive if set to off can disable the nonce count check
523 completely to work around buggy digest qop implementations in
524 certain mainstream browser versions. Default on to check the
525 nonce count to protect from authentication replay attacks.
527 "post_workaround" on|off
528 This is a workaround to certain buggy browsers who send an
529 incorrect request digest in POST requests when reusing the
530 same nonce as acquired earlier on a GET request.
533 IF HAVE_AUTH_MODULE_NEGOTIATE
534 === Negotiate authentication parameters ===
537 If you experience problems with PUT/POST requests when using
538 the this authentication scheme then you can try setting this
539 to off. This will cause Squid to forcibly close the connection
540 on the initial request where the browser asks which schemes
541 are supported by the proxy.
544 IF HAVE_AUTH_MODULE_NTLM
545 === NTLM authentication parameters ===
548 If you experience problems with PUT/POST requests when using
549 the this authentication scheme then you can try setting this
550 to off. This will cause Squid to forcibly close the connection
551 on the initial request where the browser asks which schemes
552 are supported by the proxy.
555 === Example Configuration ===
557 This configuration displays the recommended authentication scheme
558 order from most to least secure with recommended minimum configuration
559 settings for each scheme:
561 #auth_param negotiate program <uncomment and complete this line to activate>
562 #auth_param negotiate children 20 startup=0 idle=1
563 #auth_param negotiate keep_alive on
565 #auth_param digest program <uncomment and complete this line to activate>
566 #auth_param digest children 20 startup=0 idle=1
567 #auth_param digest realm Squid proxy-caching web server
568 #auth_param digest nonce_garbage_interval 5 minutes
569 #auth_param digest nonce_max_duration 30 minutes
570 #auth_param digest nonce_max_count 50
572 #auth_param ntlm program <uncomment and complete this line to activate>
573 #auth_param ntlm children 20 startup=0 idle=1
574 #auth_param ntlm keep_alive on
576 #auth_param basic program <uncomment and complete this line>
577 #auth_param basic children 5 startup=5 idle=1
578 #auth_param basic realm Squid proxy-caching web server
579 #auth_param basic credentialsttl 2 hours
582 NAME: authenticate_cache_garbage_interval
585 LOC: Config.authenticateGCInterval
587 The time period between garbage collection across the username cache.
588 This is a trade-off between memory utilization (long intervals - say
589 2 days) and CPU (short intervals - say 1 minute). Only change if you
593 NAME: authenticate_ttl
596 LOC: Config.authenticateTTL
598 The time a user & their credentials stay in the logged in
599 user cache since their last request. When the garbage
600 interval passes, all user credentials that have passed their
601 TTL are removed from memory.
604 NAME: authenticate_ip_ttl
606 LOC: Config.authenticateIpTTL
609 If you use proxy authentication and the 'max_user_ip' ACL,
610 this directive controls how long Squid remembers the IP
611 addresses associated with each user. Use a small value
612 (e.g., 60 seconds) if your users might change addresses
613 quickly, as is the case with dialup. You might be safe
614 using a larger value (e.g., 2 hours) in a corporate LAN
615 environment with relatively static address assignments.
620 -----------------------------------------------------------------------------
623 NAME: external_acl_type
624 TYPE: externalAclHelper
625 LOC: Config.externalAclHelperList
628 This option defines external acl classes using a helper program
629 to look up the status
631 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
635 ttl=n TTL in seconds for cached results (defaults to 3600
639 TTL for cached negative lookups (default same
642 grace=n Percentage remaining of TTL where a refresh of a
643 cached entry should be initiated without needing to
644 wait for a new reply. (default is for no grace period)
646 cache=n Limit the result cache size, default is 262144.
647 The expanded FORMAT value is used as the cache key, so
648 if the details in FORMAT are highly variable a larger
649 cache may be needed to produce reduction in helper load.
652 Maximum number of acl helper processes spawned to service
653 external acl lookups of this type. (default 20)
656 Minimum number of acl helper processes to spawn during
657 startup and reconfigure to service external acl lookups
658 of this type. (default 0)
661 Number of acl helper processes to keep ahead of traffic
662 loads. Squid will spawn this many at once whenever load
663 rises above the capabilities of existing processes.
664 Up to the value of children-max. (default 1)
666 concurrency=n concurrency level per process. Only used with helpers
667 capable of processing more than one query at a time.
669 queue-size=N The queue-size= option sets the maximum number of queued
670 requests. If the queued requests exceed queue size
672 The default value is set to 2*children-max.
674 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers.
676 ipv4 / ipv6 IP protocol used to communicate with this helper.
677 The default is to auto-detect IPv6 and use it when available.
680 FORMAT specifications
682 %LOGIN Authenticated user login name
683 %EXT_USER Username from previous external acl
684 %EXT_LOG Log details from previous external acl
685 %EXT_TAG Tag from previous external acl
686 %IDENT Ident user name
688 %SRCPORT Client source port
691 %PROTO Requested URL scheme
693 %PATH Requested URL path
694 %METHOD Request method
695 %MYADDR Squid interface address
696 %MYPORT Squid http_port number
697 %PATH Requested URL-path (including query-string if any)
698 %USER_CERT SSL User certificate in PEM format
699 %USER_CERTCHAIN SSL User certificate chain in PEM format
700 %USER_CERT_xx SSL User certificate subject attribute xx
701 %USER_CA_CERT_xx SSL User certificate issuer attribute xx
702 %ssl::>sni SSL client SNI sent to Squid
703 %ssl::<cert_subject SSL server certificate DN
704 %ssl::<cert_issuer SSL server certificate issuer DN
706 %>{Header} HTTP request header "Header"
708 HTTP request header "Hdr" list member "member"
710 HTTP request header list member using ; as
711 list separator. ; can be any non-alphanumeric
714 %<{Header} HTTP reply header "Header"
716 HTTP reply header "Hdr" list member "member"
718 HTTP reply header list member using ; as
719 list separator. ; can be any non-alphanumeric
722 %ACL The name of the ACL being tested.
723 %DATA The ACL arguments. If not used then any arguments
724 is automatically added at the end of the line
726 NOTE: this will encode the arguments as one token,
727 whereas the default will pass each separately.
729 %% The percent sign. Useful for helpers which need
730 an unchanging input format.
733 General request syntax:
735 [channel-ID] FORMAT-values [acl-values ...]
738 FORMAT-values consists of transaction details expanded with
739 whitespace separation per the config file FORMAT specification
740 using the FORMAT macros listed above.
742 acl-values consists of any string specified in the referencing
743 config 'acl ... external' line. see the "acl external" directive.
745 Request values sent to the helper are URL escaped to protect
746 each value in requests against whitespaces.
748 If using protocol=2.5 then the request sent to the helper is not
749 URL escaped to protect against whitespace.
751 NOTE: protocol=3.0 is deprecated as no longer necessary.
753 When using the concurrency= option the protocol is changed by
754 introducing a query channel tag in front of the request/response.
755 The query channel tag is a number between 0 and concurrency-1.
756 This value must be echoed back unchanged to Squid as the first part
757 of the response relating to its request.
760 The helper receives lines expanded per the above format specification
761 and for each input line returns 1 line starting with OK/ERR/BH result
762 code and optionally followed by additional keywords with more details.
765 General result syntax:
767 [channel-ID] result keyword=value ...
769 Result consists of one of the codes:
772 the ACL test produced a match.
775 the ACL test does not produce a match.
778 An internal error occurred in the helper, preventing
779 a result being identified.
781 The meaning of 'a match' is determined by your squid.conf
782 access control configuration. See the Squid wiki for details.
786 user= The users name (login)
788 password= The users password (for login= cache_peer option)
790 message= Message describing the reason for this response.
791 Available as %o in error pages.
792 Useful on (ERR and BH results).
794 tag= Apply a tag to a request. Only sets a tag once,
795 does not alter existing tags.
797 log= String to be logged in access.log. Available as
798 %ea in logformat specifications.
800 clt_conn_tag= Associates a TAG with the client TCP connection.
801 Please see url_rewrite_program related documentation
804 Any keywords may be sent on any response whether OK, ERR or BH.
806 All response keyword values need to be a single token with URL
807 escaping, or enclosed in double quotes (") and escaped using \ on
808 any double quotes or \ characters within the value. The wrapping
809 double quotes are removed before the value is interpreted by Squid.
810 \r and \n are also replace by CR and LF.
812 Some example key values:
816 user="J. \"Bob\" Smith"
823 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
824 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
825 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
826 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
827 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
830 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
831 DEFAULT: localhost src 127.0.0.1/32 ::1
832 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
833 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
835 Defining an Access List
837 Every access list definition must begin with an aclname and acltype,
838 followed by either type-specific arguments or a quoted filename that
841 acl aclname acltype argument ...
842 acl aclname acltype "file" ...
844 When using "file", the file should contain one item per line.
846 Some acl types supports options which changes their default behaviour.
847 The available options are:
849 -i,+i By default, regular expressions are CASE-SENSITIVE. To make them
850 case-insensitive, use the -i option. To return case-sensitive
851 use the +i option between patterns, or make a new ACL line
854 -n Disable lookups and address type conversions. If lookup or
855 conversion is required because the parameter type (IP or
856 domain name) does not match the message address type (domain
857 name or IP), then the ACL would immediately declare a mismatch
858 without any warnings or lookups.
860 -- Used to stop processing all options, in the case the first acl
861 value has '-' character as first character (for example the '-'
862 is a valid domain name)
864 Some acl types require suspending the current request in order
865 to access some external data source.
866 Those which do are marked with the tag [slow], those which
867 don't are marked as [fast].
868 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
869 for further information
871 ***** ACL TYPES AVAILABLE *****
873 acl aclname src ip-address/mask ... # clients IP address [fast]
874 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
875 acl aclname dst [-n] ip-address/mask ... # URL host's IP address [slow]
876 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
878 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
879 # The arp ACL requires the special configure option --enable-arp-acl.
880 # Furthermore, the ARP ACL code is not portable to all operating systems.
881 # It works on Linux, Solaris, Windows, FreeBSD, and some
882 # other *BSD variants.
885 # NOTE: Squid can only determine the MAC address for clients that are on
886 # the same subnet. If the client is on a different subnet,
887 # then Squid cannot find out its MAC address.
889 acl aclname srcdomain .foo.com ...
890 # reverse lookup, from client IP [slow]
891 acl aclname dstdomain [-n] .foo.com ...
892 # Destination server from URL [fast]
893 acl aclname srcdom_regex [-i] \.foo\.com ...
894 # regex matching client name [slow]
895 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
896 # regex matching server [fast]
898 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
899 # based URL is used and no match is found. The name "none" is used
900 # if the reverse lookup fails.
902 acl aclname src_as number ...
903 acl aclname dst_as number ...
905 # Except for access control, AS numbers can be used for
906 # routing of requests to specific caches. Here's an
907 # example for routing all requests for AS#1241 and only
908 # those to mycache.mydomain.net:
909 # acl asexample dst_as 1241
910 # cache_peer_access mycache.mydomain.net allow asexample
911 # cache_peer_access mycache_mydomain.net deny all
913 acl aclname peername myPeer ...
915 # match against a named cache_peer entry
916 # set unique name= on cache_peer lines for reliable use.
918 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
928 # h1:m1 must be less than h2:m2
930 acl aclname url_regex [-i] ^http:// ...
931 # regex matching on whole URL [fast]
932 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
933 # regex matching on URL login field
934 acl aclname urlpath_regex [-i] \.gif$ ...
935 # regex matching on URL path [fast]
937 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
939 acl aclname localport 3128 ... # TCP port the client connected to [fast]
940 # NP: for interception mode this is usually '80'
942 acl aclname myportname 3128 ... # *_port name [fast]
944 acl aclname proto HTTP FTP ... # request protocol [fast]
946 acl aclname method GET POST ... # HTTP request method [fast]
948 acl aclname http_status 200 301 500- 400-403 ...
949 # status code in reply [fast]
951 acl aclname browser [-i] regexp ...
952 # pattern match on User-Agent header (see also req_header below) [fast]
954 acl aclname referer_regex [-i] regexp ...
955 # pattern match on Referer header [fast]
956 # Referer is highly unreliable, so use with care
958 acl aclname ident username ...
959 acl aclname ident_regex [-i] pattern ...
960 # string match on ident output [slow]
961 # use REQUIRED to accept any non-null ident.
963 acl aclname proxy_auth [-i] username ...
964 acl aclname proxy_auth_regex [-i] pattern ...
965 # perform http authentication challenge to the client and match against
966 # supplied credentials [slow]
968 # takes a list of allowed usernames.
969 # use REQUIRED to accept any valid username.
971 # Will use proxy authentication in forward-proxy scenarios, and plain
972 # http authenticaiton in reverse-proxy scenarios
974 # NOTE: when a Proxy-Authentication header is sent but it is not
975 # needed during ACL checking the username is NOT logged
978 # NOTE: proxy_auth requires a EXTERNAL authentication program
979 # to check username/password combinations (see
980 # auth_param directive).
982 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
983 # as the browser needs to be configured for using a proxy in order
984 # to respond to proxy authentication.
986 acl aclname snmp_community string ...
987 # A community string to limit access to your SNMP Agent [fast]
990 # acl snmppublic snmp_community public
992 acl aclname maxconn number
993 # This will be matched when the client's IP address has
994 # more than <number> TCP connections established. [fast]
995 # NOTE: This only measures direct TCP links so X-Forwarded-For
996 # indirect clients are not counted.
998 acl aclname max_user_ip [-s] number
999 # This will be matched when the user attempts to log in from more
1000 # than <number> different ip addresses. The authenticate_ip_ttl
1001 # parameter controls the timeout on the ip entries. [fast]
1002 # If -s is specified the limit is strict, denying browsing
1003 # from any further IP addresses until the ttl has expired. Without
1004 # -s Squid will just annoy the user by "randomly" denying requests.
1005 # (the counter is reset each time the limit is reached and a
1006 # request is denied)
1007 # NOTE: in acceleration mode or where there is mesh of child proxies,
1008 # clients may appear to come from multiple addresses if they are
1009 # going through proxy farms, so a limit of 1 may cause user problems.
1011 acl aclname random probability
1012 # Pseudo-randomly match requests. Based on the probability given.
1013 # Probability may be written as a decimal (0.333), fraction (1/3)
1014 # or ratio of matches:non-matches (3:5).
1016 acl aclname req_mime_type [-i] mime-type ...
1017 # regex match against the mime type of the request generated
1018 # by the client. Can be used to detect file upload or some
1019 # types HTTP tunneling requests [fast]
1020 # NOTE: This does NOT match the reply. You cannot use this
1021 # to match the returned file type.
1023 acl aclname req_header header-name [-i] any\.regex\.here
1024 # regex match against any of the known request headers. May be
1025 # thought of as a superset of "browser", "referer" and "mime-type"
1028 acl aclname rep_mime_type [-i] mime-type ...
1029 # regex match against the mime type of the reply received by
1030 # squid. Can be used to detect file download or some
1031 # types HTTP tunneling requests. [fast]
1032 # NOTE: This has no effect in http_access rules. It only has
1033 # effect in rules that affect the reply data stream such as
1034 # http_reply_access.
1036 acl aclname rep_header header-name [-i] any\.regex\.here
1037 # regex match against any of the known reply headers. May be
1038 # thought of as a superset of "browser", "referer" and "mime-type"
1041 acl aclname external class_name [arguments...]
1042 # external ACL lookup via a helper class defined by the
1043 # external_acl_type directive [slow]
1045 acl aclname user_cert attribute values...
1046 # match against attributes in a user SSL certificate
1047 # attribute is one of DN/C/O/CN/L/ST [fast]
1049 acl aclname ca_cert attribute values...
1050 # match against attributes a users issuing CA SSL certificate
1051 # attribute is one of DN/C/O/CN/L/ST [fast]
1053 acl aclname ext_user username ...
1054 acl aclname ext_user_regex [-i] pattern ...
1055 # string match on username returned by external acl helper [slow]
1056 # use REQUIRED to accept any non-null user name.
1058 acl aclname tag tagvalue ...
1059 # string match on tag returned by external acl helper [fast]
1060 # DEPRECATED. Only the first tag will match with this ACL.
1061 # Use the 'note' ACL instead for handling multiple tag values.
1063 acl aclname hier_code codename ...
1064 # string match against squid hierarchy code(s); [fast]
1065 # e.g., DIRECT, PARENT_HIT, NONE, etc.
1067 # NOTE: This has no effect in http_access rules. It only has
1068 # effect in rules that affect the reply data stream such as
1069 # http_reply_access.
1071 acl aclname note name [value ...]
1072 # match transaction annotation [fast]
1073 # Without values, matches any annotation with a given name.
1074 # With value(s), matches any annotation with a given name that
1075 # also has one of the given values.
1076 # Names and values are compared using a string equality test.
1077 # Annotation sources include note and adaptation_meta directives
1078 # as well as helper and eCAP responses.
1080 acl aclname adaptation_service service ...
1081 # Matches the name of any icap_service, ecap_service,
1082 # adaptation_service_set, or adaptation_service_chain that Squid
1083 # has used (or attempted to use) for the master transaction.
1084 # This ACL must be defined after the corresponding adaptation
1085 # service is named in squid.conf. This ACL is usable with
1086 # adaptation_meta because it starts matching immediately after
1087 # the service has been selected for adaptation.
1090 acl aclname ssl_error errorname
1091 # match against SSL certificate validation error [fast]
1093 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1096 # The following can be used as shortcuts for certificate properties:
1097 # [ssl::]certHasExpired: the "not after" field is in the past
1098 # [ssl::]certNotYetValid: the "not before" field is in the future
1099 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1100 # [ssl::]certSelfSigned: The certificate is self signed.
1101 # [ssl::]certDomainMismatch: The certificate CN domain does not
1102 # match the name the name of the host we are connecting to.
1104 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1105 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1106 # predefined ACLs, just like the 'all' ACL.
1108 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1109 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1111 acl aclname server_cert_fingerprint [-sha1] fingerprint
1112 # match against server SSL certificate fingerprint [fast]
1114 # The fingerprint is the digest of the DER encoded version
1115 # of the whole certificate. The user should use the form: XX:XX:...
1116 # Optional argument specifies the digest algorithm to use.
1117 # The SHA1 digest algorithm is the default and is currently
1118 # the only algorithm supported (-sha1).
1120 acl aclname at_step step
1121 # match against the current step during ssl_bump evaluation [fast]
1122 # Never matches and should not be used outside the ssl_bump context.
1124 # At each SslBump step, Squid evaluates ssl_bump directives to find
1125 # the next bumping action (e.g., peek or splice). Valid SslBump step
1126 # values and the corresponding ssl_bump evaluation moments are:
1127 # SslBump1: After getting TCP-level and HTTP CONNECT info.
1128 # SslBump2: After getting SSL Client Hello info.
1129 # SslBump3: After getting SSL Server Hello info.
1131 acl aclname any-of acl1 acl2 ...
1132 # match any one of the acls [fast or slow]
1133 # The first matching ACL stops further ACL evaluation.
1135 # ACLs from multiple any-of lines with the same name are ORed.
1136 # For example, A = (a1 or a2) or (a3 or a4) can be written as
1137 # acl A any-of a1 a2
1138 # acl A any-of a3 a4
1140 # This group ACL is fast if all evaluated ACLs in the group are fast
1141 # and slow otherwise.
1143 acl aclname all-of acl1 acl2 ...
1144 # match all of the acls [fast or slow]
1145 # The first mismatching ACL stops further ACL evaluation.
1147 # ACLs from multiple all-of lines with the same name are ORed.
1148 # For example, B = (b1 and b2) or (b3 and b4) can be written as
1149 # acl B all-of b1 b2
1150 # acl B all-of b3 b4
1152 # This group ACL is fast if all evaluated ACLs in the group are fast
1153 # and slow otherwise.
1156 acl macaddress arp 09:00:2b:23:45:67
1157 acl myexample dst_as 1241
1158 acl password proxy_auth REQUIRED
1159 acl fileupload req_mime_type -i ^multipart/form-data$
1160 acl javascript rep_mime_type -i ^application/x-javascript$
1164 # Recommended minimum configuration:
1167 # Example rule allowing access from your local networks.
1168 # Adapt to list your (internal) IP networks from where browsing
1170 acl localnet src 0.0.0.1-0.255.255.255 # RFC 1122 "this" network (LAN)
1171 acl localnet src 10.0.0.0/8 # RFC 1918 local private network (LAN)
1172 acl localnet src 100.64.0.0/10 # RFC 6598 shared address space (CGN)
1173 acl localhet src 169.254.0.0/16 # RFC 3927 link-local (directly plugged) machines
1174 acl localnet src 172.16.0.0/12 # RFC 1918 local private network (LAN)
1175 acl localnet src 192.168.0.0/16 # RFC 1918 local private network (LAN)
1176 acl localnet src fc00::/7 # RFC 4193 local private network range
1177 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1179 acl SSL_ports port 443
1180 acl Safe_ports port 80 # http
1181 acl Safe_ports port 21 # ftp
1182 acl Safe_ports port 443 # https
1183 acl Safe_ports port 70 # gopher
1184 acl Safe_ports port 210 # wais
1185 acl Safe_ports port 1025-65535 # unregistered ports
1186 acl Safe_ports port 280 # http-mgmt
1187 acl Safe_ports port 488 # gss-http
1188 acl Safe_ports port 591 # filemaker
1189 acl Safe_ports port 777 # multiling http
1190 acl CONNECT method CONNECT
1194 NAME: proxy_protocol_access
1196 LOC: Config.accessList.proxyProtocol
1198 DEFAULT_DOC: all TCP connections to ports with require-proxy-header will be denied
1200 Determine which client proxies can be trusted to provide correct
1201 information regarding real client IP address using PROXY protocol.
1203 Requests may pass through a chain of several other proxies
1204 before reaching us. The original source details may by sent in:
1205 * HTTP message Forwarded header, or
1206 * HTTP message X-Forwarded-For header, or
1207 * PROXY protocol connection header.
1209 This directive is solely for validating new PROXY protocol
1210 connections received from a port flagged with require-proxy-header.
1211 It is checked only once after TCP connection setup.
1213 A deny match results in TCP connection closure.
1215 An allow match is required for Squid to permit the corresponding
1216 TCP connection, before Squid even looks for HTTP request headers.
1217 If there is an allow match, Squid starts using PROXY header information
1218 to determine the source address of the connection for all future ACL
1219 checks, logging, etc.
1221 SECURITY CONSIDERATIONS:
1223 Any host from which we accept client IP details can place
1224 incorrect information in the relevant header, and Squid
1225 will use the incorrect information as if it were the
1226 source address of the request. This may enable remote
1227 hosts to bypass any access control restrictions that are
1228 based on the client's source addresses.
1230 This clause only supports fast acl types.
1231 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1234 NAME: follow_x_forwarded_for
1236 IFDEF: FOLLOW_X_FORWARDED_FOR
1237 LOC: Config.accessList.followXFF
1238 DEFAULT_IF_NONE: deny all
1239 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1241 Determine which client proxies can be trusted to provide correct
1242 information regarding real client IP address.
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 PROXY protocol connections are controlled by the proxy_protocol_access
1251 directive which is checked before this.
1253 If a request reaches us from a source that is allowed by this
1254 directive, then we trust the information it provides regarding
1255 the IP of the client it received from (if any).
1257 For the purpose of ACLs used in this directive the src ACL type always
1258 matches the address we are testing and srcdomain matches its rDNS.
1260 On each HTTP request Squid checks for X-Forwarded-For header fields.
1261 If found the header values are iterated in reverse order and an allow
1262 match is required for Squid to continue on to the next value.
1263 The verification ends when a value receives a deny match, cannot be
1264 tested, or there are no more values to test.
1265 NOTE: Squid does not yet follow the Forwarded HTTP header.
1267 The end result of this process is an IP address that we will
1268 refer to as the indirect client address. This address may
1269 be treated as the client address for access control, ICAP, delay
1270 pools and logging, depending on the acl_uses_indirect_client,
1271 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1272 log_uses_indirect_client and tproxy_uses_indirect_client options.
1274 This clause only supports fast acl types.
1275 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1277 SECURITY CONSIDERATIONS:
1279 Any host from which we accept client IP details can place
1280 incorrect information in the relevant header, and Squid
1281 will use the incorrect information as if it were the
1282 source address of the request. This may enable remote
1283 hosts to bypass any access control restrictions that are
1284 based on the client's source addresses.
1288 acl localhost src 127.0.0.1
1289 acl my_other_proxy srcdomain .proxy.example.com
1290 follow_x_forwarded_for allow localhost
1291 follow_x_forwarded_for allow my_other_proxy
1294 NAME: acl_uses_indirect_client
1297 IFDEF: FOLLOW_X_FORWARDED_FOR
1299 LOC: Config.onoff.acl_uses_indirect_client
1301 Controls whether the indirect client address
1302 (see follow_x_forwarded_for) is used instead of the
1303 direct client address in acl matching.
1305 NOTE: maxconn ACL considers direct TCP links and indirect
1306 clients will always have zero. So no match.
1309 NAME: delay_pool_uses_indirect_client
1312 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1314 LOC: Config.onoff.delay_pool_uses_indirect_client
1316 Controls whether the indirect client address
1317 (see follow_x_forwarded_for) is used instead of the
1318 direct client address in delay pools.
1321 NAME: log_uses_indirect_client
1324 IFDEF: FOLLOW_X_FORWARDED_FOR
1326 LOC: Config.onoff.log_uses_indirect_client
1328 Controls whether the indirect client address
1329 (see follow_x_forwarded_for) is used instead of the
1330 direct client address in the access log.
1333 NAME: tproxy_uses_indirect_client
1336 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1338 LOC: Config.onoff.tproxy_uses_indirect_client
1340 Controls whether the indirect client address
1341 (see follow_x_forwarded_for) is used instead of the
1342 direct client address when spoofing the outgoing client.
1344 This has no effect on requests arriving in non-tproxy
1347 SECURITY WARNING: Usage of this option is dangerous
1348 and should not be used trivially. Correct configuration
1349 of follow_x_forewarded_for with a limited set of trusted
1350 sources is required to prevent abuse of your proxy.
1353 NAME: spoof_client_ip
1355 LOC: Config.accessList.spoof_client_ip
1357 DEFAULT_DOC: Allow spoofing on all TPROXY traffic.
1359 Control client IP address spoofing of TPROXY traffic based on
1360 defined access lists.
1362 spoof_client_ip allow|deny [!]aclname ...
1364 If there are no "spoof_client_ip" lines present, the default
1365 is to "allow" spoofing of any suitable request.
1367 Note that the cache_peer "no-tproxy" option overrides this ACL.
1369 This clause supports fast acl types.
1370 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1375 LOC: Config.accessList.http
1376 DEFAULT_IF_NONE: deny all
1377 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1379 Allowing or Denying access based on defined access lists
1381 To allow or deny a message received on an HTTP, HTTPS, or FTP port:
1382 http_access allow|deny [!]aclname ...
1384 NOTE on default values:
1386 If there are no "access" lines present, the default is to deny
1389 If none of the "access" lines cause a match, the default is the
1390 opposite of the last line in the list. If the last line was
1391 deny, the default is allow. Conversely, if the last line
1392 is allow, the default will be deny. For these reasons, it is a
1393 good idea to have an "deny all" entry at the end of your access
1394 lists to avoid potential confusion.
1396 This clause supports both fast and slow acl types.
1397 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1402 # Recommended minimum Access Permission configuration:
1404 # Deny requests to certain unsafe ports
1405 http_access deny !Safe_ports
1407 # Deny CONNECT to other than secure SSL ports
1408 http_access deny CONNECT !SSL_ports
1410 # Only allow cachemgr access from localhost
1411 http_access allow localhost manager
1412 http_access deny manager
1414 # We strongly recommend the following be uncommented to protect innocent
1415 # web applications running on the proxy server who think the only
1416 # one who can access services on "localhost" is a local user
1417 #http_access deny to_localhost
1420 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1423 # Example rule allowing access from your local networks.
1424 # Adapt localnet in the ACL section to list your (internal) IP networks
1425 # from where browsing should be allowed
1426 http_access allow localnet
1427 http_access allow localhost
1429 # And finally deny all other access to this proxy
1430 http_access deny all
1434 NAME: adapted_http_access http_access2
1436 LOC: Config.accessList.adapted_http
1438 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1440 Allowing or Denying access based on defined access lists
1442 Essentially identical to http_access, but runs after redirectors
1443 and ICAP/eCAP adaptation. Allowing access control based on their
1446 If not set then only http_access is used.
1449 NAME: http_reply_access
1451 LOC: Config.accessList.reply
1453 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1455 Allow replies to client requests. This is complementary to http_access.
1457 http_reply_access allow|deny [!] aclname ...
1459 NOTE: if there are no access lines present, the default is to allow
1462 If none of the access lines cause a match the opposite of the
1463 last line will apply. Thus it is good practice to end the rules
1464 with an "allow all" or "deny all" entry.
1466 This clause supports both fast and slow acl types.
1467 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1472 LOC: Config.accessList.icp
1474 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1476 Allowing or Denying access to the ICP port based on defined
1479 icp_access allow|deny [!]aclname ...
1481 NOTE: The default if no icp_access lines are present is to
1482 deny all traffic. This default may cause problems with peers
1485 This clause only supports fast acl types.
1486 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1488 # Allow ICP queries from local networks only
1489 #icp_access allow localnet
1490 #icp_access deny all
1496 LOC: Config.accessList.htcp
1498 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1500 Allowing or Denying access to the HTCP port based on defined
1503 htcp_access allow|deny [!]aclname ...
1505 See also htcp_clr_access for details on access control for
1506 cache purge (CLR) HTCP messages.
1508 NOTE: The default if no htcp_access lines are present is to
1509 deny all traffic. This default may cause problems with peers
1510 using the htcp option.
1512 This clause only supports fast acl types.
1513 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1515 # Allow HTCP queries from local networks only
1516 #htcp_access allow localnet
1517 #htcp_access deny all
1520 NAME: htcp_clr_access
1523 LOC: Config.accessList.htcp_clr
1525 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1527 Allowing or Denying access to purge content using HTCP based
1528 on defined access lists.
1529 See htcp_access for details on general HTCP access control.
1531 htcp_clr_access allow|deny [!]aclname ...
1533 This clause only supports fast acl types.
1534 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1536 # Allow HTCP CLR requests from trusted peers
1537 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1538 htcp_clr_access allow htcp_clr_peer
1539 htcp_clr_access deny all
1544 LOC: Config.accessList.miss
1546 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1548 Determins whether network access is permitted when satisfying a request.
1551 to force your neighbors to use you as a sibling instead of
1554 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1555 miss_access deny !localclients
1556 miss_access allow all
1558 This means only your local clients are allowed to fetch relayed/MISS
1559 replies from the network and all other clients can only fetch cached
1562 The default for this setting allows all clients who passed the
1563 http_access rules to relay via this proxy.
1565 This clause only supports fast acl types.
1566 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1569 NAME: ident_lookup_access
1573 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1574 LOC: Ident::TheConfig.identLookup
1576 A list of ACL elements which, if matched, cause an ident
1577 (RFC 931) lookup to be performed for this request. For
1578 example, you might choose to always perform ident lookups
1579 for your main multi-user Unix boxes, but not for your Macs
1580 and PCs. By default, ident lookups are not performed for
1583 To enable ident lookups for specific client addresses, you
1584 can follow this example:
1586 acl ident_aware_hosts src 198.168.1.0/24
1587 ident_lookup_access allow ident_aware_hosts
1588 ident_lookup_access deny all
1590 Only src type ACL checks are fully supported. A srcdomain
1591 ACL might work at times, but it will not always provide
1594 This clause only supports fast acl types.
1595 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1598 NAME: reply_body_max_size
1599 COMMENT: size [acl acl...]
1602 DEFAULT_DOC: No limit is applied.
1603 LOC: Config.ReplyBodySize
1605 This option specifies the maximum size of a reply body. It can be
1606 used to prevent users from downloading very large files, such as
1607 MP3's and movies. When the reply headers are received, the
1608 reply_body_max_size lines are processed, and the first line where
1609 all (if any) listed ACLs are true is used as the maximum body size
1612 This size is checked twice. First when we get the reply headers,
1613 we check the content-length value. If the content length value exists
1614 and is larger than the allowed size, the request is denied and the
1615 user receives an error message that says "the request or reply
1616 is too large." If there is no content-length, and the reply
1617 size exceeds this limit, the client's connection is just closed
1618 and they will receive a partial reply.
1620 WARNING: downstream caches probably can not detect a partial reply
1621 if there is no content-length header, so they will cache
1622 partial responses and give them out as hits. You should NOT
1623 use this option if you have downstream caches.
1625 WARNING: A maximum size smaller than the size of squid's error messages
1626 will cause an infinite loop and crash squid. Ensure that the smallest
1627 non-zero value you use is greater that the maximum header size plus
1628 the size of your largest error page.
1630 If you set this parameter none (the default), there will be
1633 Configuration Format is:
1634 reply_body_max_size SIZE UNITS [acl ...]
1636 reply_body_max_size 10 MB
1642 -----------------------------------------------------------------------------
1645 NAME: http_port ascii_port
1650 Usage: port [mode] [options]
1651 hostname:port [mode] [options]
1652 1.2.3.4:port [mode] [options]
1654 The socket addresses where Squid will listen for HTTP client
1655 requests. You may specify multiple socket addresses.
1656 There are three forms: port alone, hostname with port, and
1657 IP address with port. If you specify a hostname or IP
1658 address, Squid binds the socket to that specific
1659 address. Most likely, you do not need to bind to a specific
1660 address, so you can use the port number alone.
1662 If you are running Squid in accelerator mode, you
1663 probably want to listen on port 80 also, or instead.
1665 The -a command line option may be used to specify additional
1666 port(s) where Squid listens for proxy request. Such ports will
1667 be plain proxy ports with no options.
1669 You may specify multiple socket addresses on multiple lines.
1673 intercept Support for IP-Layer interception of
1674 outgoing requests without browser settings.
1675 NP: disables authentication and IPv6 on the port.
1677 tproxy Support Linux TPROXY for spoofing outgoing
1678 connections using the client IP address.
1679 NP: disables authentication and maybe IPv6 on the port.
1681 accel Accelerator / reverse proxy mode
1683 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1684 establish secure connection with the client and with
1685 the server, decrypt HTTPS messages as they pass through
1686 Squid, and treat them as unencrypted HTTP messages,
1687 becoming the man-in-the-middle.
1689 The ssl_bump option is required to fully enable
1690 bumping of CONNECT requests.
1692 Omitting the mode flag causes default forward proxy mode to be used.
1695 Accelerator Mode Options:
1697 defaultsite=domainname
1698 What to use for the Host: header if it is not present
1699 in a request. Determines what site (not origin server)
1700 accelerators should consider the default.
1702 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1704 protocol= Protocol to reconstruct accelerated and intercepted
1705 requests with. Defaults to HTTP/1.1 for http_port and
1706 HTTPS/1.1 for https_port.
1707 When an unsupported value is configured Squid will
1708 produce a FATAL error.
1709 Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
1711 vport Virtual host port support. Using the http_port number
1712 instead of the port passed on Host: headers.
1714 vport=NN Virtual host port support. Using the specified port
1715 number instead of the port passed on Host: headers.
1718 Act as if this Squid is the origin server.
1719 This currently means generate new Date: and Expires:
1720 headers on HIT instead of adding Age:.
1722 ignore-cc Ignore request Cache-Control headers.
1724 WARNING: This option violates HTTP specifications if
1725 used in non-accelerator setups.
1727 allow-direct Allow direct forwarding in accelerator mode. Normally
1728 accelerated requests are denied direct forwarding as if
1729 never_direct was used.
1731 WARNING: this option opens accelerator mode to security
1732 vulnerabilities usually only affecting in interception
1733 mode. Make sure to protect forwarding with suitable
1734 http_access rules when using this.
1737 SSL Bump Mode Options:
1738 In addition to these options ssl-bump requires TLS/SSL options.
1740 generate-host-certificates[=<on|off>]
1741 Dynamically create SSL server certificates for the
1742 destination hosts of bumped CONNECT requests.When
1743 enabled, the cert and key options are used to sign
1744 generated certificates. Otherwise generated
1745 certificate will be selfsigned.
1746 If there is a CA certificate lifetime of the generated
1747 certificate equals lifetime of the CA certificate. If
1748 generated certificate is selfsigned lifetime is three
1750 This option is enabled by default when ssl-bump is used.
1751 See the ssl-bump option above for more information.
1753 dynamic_cert_mem_cache_size=SIZE
1754 Approximate total RAM size spent on cached generated
1755 certificates. If set to zero, caching is disabled. The
1756 default value is 4MB.
1760 cert= Path to SSL certificate (PEM format).
1762 key= Path to SSL private key file (PEM format)
1763 if not specified, the certificate file is
1764 assumed to be a combined certificate and
1767 version= The version of SSL/TLS supported
1768 1 automatic (default)
1774 cipher= Colon separated list of supported ciphers.
1775 NOTE: some ciphers such as EDH ciphers depend on
1776 additional settings. If those settings are
1777 omitted the ciphers may be silently ignored
1778 by the OpenSSL library.
1780 options= Various SSL implementation options. The most important
1782 NO_SSLv3 Disallow the use of SSLv3
1783 NO_TLSv1 Disallow the use of TLSv1.0
1784 NO_TLSv1_1 Disallow the use of TLSv1.1
1785 NO_TLSv1_2 Disallow the use of TLSv1.2
1786 SINGLE_DH_USE Always create a new key when using
1787 temporary/ephemeral DH key exchanges
1788 ALL Enable various bug workarounds
1789 suggested as "harmless" by OpenSSL
1790 Be warned that this reduces SSL/TLS
1791 strength to some attacks.
1792 See OpenSSL SSL_CTX_set_options documentation for a
1793 complete list of options.
1795 clientca= File containing the list of CAs to use when
1796 requesting a client certificate.
1798 cafile= File containing additional CA certificates to
1799 use when verifying client certificates. If unset
1800 clientca will be used.
1802 capath= Directory containing additional CA certificates
1803 and CRL lists to use when verifying client certificates.
1805 crlfile= File of additional CRL lists to use when verifying
1806 the client certificate, in addition to CRLs stored in
1807 the capath. Implies VERIFY_CRL flag below.
1809 dhparams= File containing DH parameters for temporary/ephemeral
1810 DH key exchanges. See OpenSSL documentation for details
1811 on how to create this file.
1812 WARNING: EDH ciphers will be silently disabled if this
1815 sslflags= Various flags modifying the use of SSL:
1817 Don't request client certificates
1818 immediately, but wait until acl processing
1819 requires a certificate (not yet implemented).
1821 Don't use the default CA lists built in
1824 Don't allow for session reuse. Each connection
1825 will result in a new SSL session.
1827 Verify CRL lists when accepting client
1830 Verify CRL lists for all certificates in the
1831 client certificate chain.
1833 sslcontext= SSL session ID context identifier.
1837 connection-auth[=on|off]
1838 use connection-auth=off to tell Squid to prevent
1839 forwarding Microsoft connection oriented authentication
1840 (NTLM, Negotiate and Kerberos)
1842 disable-pmtu-discovery=
1843 Control Path-MTU discovery usage:
1844 off lets OS decide on what to do (default).
1845 transparent disable PMTU discovery when transparent
1847 always disable always PMTU discovery.
1849 In many setups of transparently intercepting proxies
1850 Path-MTU discovery can not work on traffic towards the
1851 clients. This is the case when the intercepting device
1852 does not fully track connections and fails to forward
1853 ICMP must fragment messages to the cache server. If you
1854 have such setup and experience that certain clients
1855 sporadically hang or never complete requests set
1856 disable-pmtu-discovery option to 'transparent'.
1858 name= Specifies a internal name for the port. Defaults to
1859 the port specification (port or addr:port)
1861 tcpkeepalive[=idle,interval,timeout]
1862 Enable TCP keepalive probes of idle connections.
1863 In seconds; idle is the initial time before TCP starts
1864 probing the connection, interval how often to probe, and
1865 timeout the time before giving up.
1867 require-proxy-header
1868 Require PROXY protocol version 1 or 2 connections.
1869 The proxy_protocol_access is required to whitelist
1870 downstream proxies which can be trusted.
1872 If you run Squid on a dual-homed machine with an internal
1873 and an external interface we recommend you to specify the
1874 internal address:port in http_port. This way Squid will only be
1875 visible on the internal address.
1879 # Squid normally listens to port 3128
1880 http_port @DEFAULT_HTTP_PORT@
1890 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1892 The socket address where Squid will listen for client requests made
1893 over TLS or SSL connections. Commonly referred to as HTTPS.
1895 This is most useful for situations where you are running squid in
1896 accelerator mode and you want to do the SSL work at the accelerator level.
1898 You may specify multiple socket addresses on multiple lines,
1899 each with their own SSL certificate and/or options.
1903 accel Accelerator / reverse proxy mode
1905 intercept Support for IP-Layer interception of
1906 outgoing requests without browser settings.
1907 NP: disables authentication and IPv6 on the port.
1909 tproxy Support Linux TPROXY for spoofing outgoing
1910 connections using the client IP address.
1911 NP: disables authentication and maybe IPv6 on the port.
1913 ssl-bump For each intercepted connection allowed by ssl_bump
1914 ACLs, establish a secure connection with the client and with
1915 the server, decrypt HTTPS messages as they pass through
1916 Squid, and treat them as unencrypted HTTP messages,
1917 becoming the man-in-the-middle.
1919 An "ssl_bump server-first" match is required to
1920 fully enable bumping of intercepted SSL connections.
1922 Requires tproxy or intercept.
1924 Omitting the mode flag causes default forward proxy mode to be used.
1927 See http_port for a list of generic options
1932 cert= Path to SSL certificate (PEM format).
1934 key= Path to SSL private key file (PEM format)
1935 if not specified, the certificate file is
1936 assumed to be a combined certificate and
1939 version= The version of SSL/TLS supported
1940 1 automatic (default)
1944 cipher= Colon separated list of supported ciphers.
1946 options= Various SSL engine options. The most important
1948 NO_SSLv3 Disallow the use of SSLv3
1949 NO_TLSv1 Disallow the use of TLSv1
1950 SINGLE_DH_USE Always create a new key when using
1951 temporary/ephemeral DH key exchanges
1952 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1953 documentation for a complete list of options.
1955 clientca= File containing the list of CAs to use when
1956 requesting a client certificate.
1958 cafile= File containing additional CA certificates to
1959 use when verifying client certificates. If unset
1960 clientca will be used.
1962 capath= Directory containing additional CA certificates
1963 and CRL lists to use when verifying client certificates.
1965 crlfile= File of additional CRL lists to use when verifying
1966 the client certificate, in addition to CRLs stored in
1967 the capath. Implies VERIFY_CRL flag below.
1969 dhparams= File containing DH parameters for temporary/ephemeral
1972 sslflags= Various flags modifying the use of SSL:
1974 Don't request client certificates
1975 immediately, but wait until acl processing
1976 requires a certificate (not yet implemented).
1978 Don't use the default CA lists built in
1981 Don't allow for session reuse. Each connection
1982 will result in a new SSL session.
1984 Verify CRL lists when accepting client
1987 Verify CRL lists for all certificates in the
1988 client certificate chain.
1990 sslcontext= SSL session ID context identifier.
1992 generate-host-certificates[=<on|off>]
1993 Dynamically create SSL server certificates for the
1994 destination hosts of bumped SSL requests.When
1995 enabled, the cert and key options are used to sign
1996 generated certificates. Otherwise generated
1997 certificate will be selfsigned.
1998 If there is CA certificate life time of generated
1999 certificate equals lifetime of CA certificate. If
2000 generated certificate is selfsigned lifetime is three
2002 This option is enabled by default when SslBump is used.
2003 See the sslBump option above for more information.
2005 dynamic_cert_mem_cache_size=SIZE
2006 Approximate total RAM size spent on cached generated
2007 certificates. If set to zero, caching is disabled. The
2008 default value is 4MB.
2010 See http_port for a list of available options.
2018 Enables Native FTP proxy by specifying the socket address where Squid
2019 listens for FTP client requests. See http_port directive for various
2020 ways to specify the listening address and mode.
2022 Usage: ftp_port address [mode] [options]
2024 WARNING: This is a new, experimental, complex feature that has seen
2025 limited production exposure. Some Squid modules (e.g., caching) do not
2026 currently work with native FTP proxying, and many features have not
2027 even been tested for compatibility. Test well before deploying!
2029 Native FTP proxying differs substantially from proxying HTTP requests
2030 with ftp:// URIs because Squid works as an FTP server and receives
2031 actual FTP commands (rather than HTTP requests with FTP URLs).
2033 Native FTP commands accepted at ftp_port are internally converted or
2034 wrapped into HTTP-like messages. The same happens to Native FTP
2035 responses received from FTP origin servers. Those HTTP-like messages
2036 are shoveled through regular access control and adaptation layers
2037 between the FTP client and the FTP origin server. This allows Squid to
2038 examine, adapt, block, and log FTP exchanges. Squid reuses most HTTP
2039 mechanisms when shoveling wrapped FTP messages. For example,
2040 http_access and adaptation_access directives are used.
2044 intercept Same as http_port intercept. The FTP origin address is
2045 determined based on the intended destination of the
2046 intercepted connection.
2048 tproxy Support Linux TPROXY for spoofing outgoing
2049 connections using the client IP address.
2050 NP: disables authentication and maybe IPv6 on the port.
2052 By default (i.e., without an explicit mode option), Squid extracts the
2053 FTP origin address from the login@origin parameter of the FTP USER
2054 command. Many popular FTP clients support such native FTP proxying.
2058 name=token Specifies an internal name for the port. Defaults to
2059 the port address. Usable with myportname ACL.
2062 Enables tracking of FTP directories by injecting extra
2063 PWD commands and adjusting Request-URI (in wrapping
2064 HTTP requests) to reflect the current FTP server
2065 directory. Tracking is disabled by default.
2067 protocol=FTP Protocol to reconstruct accelerated and intercepted
2068 requests with. Defaults to FTP. No other accepted
2069 values have been tested with. An unsupported value
2070 results in a FATAL error. Accepted values are FTP,
2071 HTTP (or HTTP/1.1), and HTTPS (or HTTPS/1.1).
2073 Other http_port modes and options that are not specific to HTTP and
2074 HTTPS may also work.
2077 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
2080 LOC: Ip::Qos::TheConfig.tosToServer
2082 Allows you to select a TOS/Diffserv value for packets outgoing
2083 on the server side, based on an ACL.
2085 tcp_outgoing_tos ds-field [!]aclname ...
2087 Example where normal_service_net uses the TOS value 0x00
2088 and good_service_net uses 0x20
2090 acl normal_service_net src 10.0.0.0/24
2091 acl good_service_net src 10.0.1.0/24
2092 tcp_outgoing_tos 0x00 normal_service_net
2093 tcp_outgoing_tos 0x20 good_service_net
2095 TOS/DSCP values really only have local significance - so you should
2096 know what you're specifying. For more information, see RFC2474,
2097 RFC2475, and RFC3260.
2099 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2100 "default" to use whatever default your host has. Note that in
2101 practice often only multiples of 4 is usable as the two rightmost bits
2102 have been redefined for use by ECN (RFC 3168 section 23.1).
2104 Processing proceeds in the order specified, and stops at first fully
2107 Only fast ACLs are supported.
2110 NAME: clientside_tos
2113 LOC: Ip::Qos::TheConfig.tosToClient
2115 Allows you to select a TOS/Diffserv value for packets being transmitted
2116 on the client-side, based on an ACL.
2118 clientside_tos ds-field [!]aclname ...
2120 Example where normal_service_net uses the TOS value 0x00
2121 and good_service_net uses 0x20
2123 acl normal_service_net src 10.0.0.0/24
2124 acl good_service_net src 10.0.1.0/24
2125 clientside_tos 0x00 normal_service_net
2126 clientside_tos 0x20 good_service_net
2128 Note: This feature is incompatible with qos_flows. Any TOS values set here
2129 will be overwritten by TOS values in qos_flows.
2132 NAME: tcp_outgoing_mark
2134 IFDEF: SO_MARK&&USE_LIBCAP
2136 LOC: Ip::Qos::TheConfig.nfmarkToServer
2138 Allows you to apply a Netfilter mark value to outgoing packets
2139 on the server side, based on an ACL.
2141 tcp_outgoing_mark mark-value [!]aclname ...
2143 Example where normal_service_net uses the mark value 0x00
2144 and good_service_net uses 0x20
2146 acl normal_service_net src 10.0.0.0/24
2147 acl good_service_net src 10.0.1.0/24
2148 tcp_outgoing_mark 0x00 normal_service_net
2149 tcp_outgoing_mark 0x20 good_service_net
2151 Only fast ACLs are supported.
2154 NAME: clientside_mark
2156 IFDEF: SO_MARK&&USE_LIBCAP
2158 LOC: Ip::Qos::TheConfig.nfmarkToClient
2160 Allows you to apply a Netfilter mark value to packets being transmitted
2161 on the client-side, based on an ACL.
2163 clientside_mark mark-value [!]aclname ...
2165 Example where normal_service_net uses the mark value 0x00
2166 and good_service_net uses 0x20
2168 acl normal_service_net src 10.0.0.0/24
2169 acl good_service_net src 10.0.1.0/24
2170 clientside_mark 0x00 normal_service_net
2171 clientside_mark 0x20 good_service_net
2173 Note: This feature is incompatible with qos_flows. Any mark values set here
2174 will be overwritten by mark values in qos_flows.
2181 LOC: Ip::Qos::TheConfig
2183 Allows you to select a TOS/DSCP value to mark outgoing
2184 connections to the client, based on where the reply was sourced.
2185 For platforms using netfilter, allows you to set a netfilter mark
2186 value instead of, or in addition to, a TOS value.
2188 By default this functionality is disabled. To enable it with the default
2189 settings simply use "qos_flows mark" or "qos_flows tos". Default
2190 settings will result in the netfilter mark or TOS value being copied
2191 from the upstream connection to the client. Note that it is the connection
2192 CONNMARK value not the packet MARK value that is copied.
2194 It is not currently possible to copy the mark or TOS value from the
2195 client to the upstream connection request.
2197 TOS values really only have local significance - so you should
2198 know what you're specifying. For more information, see RFC2474,
2199 RFC2475, and RFC3260.
2201 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
2202 in practice often only multiples of 4 is usable as the two rightmost bits
2203 have been redefined for use by ECN (RFC 3168 section 23.1).
2205 Mark values can be any unsigned 32-bit integer value.
2207 This setting is configured by setting the following values:
2209 tos|mark Whether to set TOS or netfilter mark values
2211 local-hit=0xFF Value to mark local cache hits.
2213 sibling-hit=0xFF Value to mark hits from sibling peers.
2215 parent-hit=0xFF Value to mark hits from parent peers.
2217 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2218 over the preserve-miss feature (see below), unless
2219 mask is specified, in which case only the bits
2220 specified in the mask are written.
2222 The TOS variant of the following features are only possible on Linux
2223 and require your kernel to be patched with the TOS preserving ZPH
2224 patch, available from http://zph.bratcheda.org
2225 No patch is needed to preserve the netfilter mark, which will work
2226 with all variants of netfilter.
2228 disable-preserve-miss
2229 This option disables the preservation of the TOS or netfilter
2230 mark. By default, the existing TOS or netfilter mark value of
2231 the response coming from the remote server will be retained
2232 and masked with miss-mark.
2233 NOTE: in the case of a netfilter mark, the mark must be set on
2234 the connection (using the CONNMARK target) not on the packet
2238 Allows you to mask certain bits in the TOS or mark value
2239 received from the remote server, before copying the value to
2240 the TOS sent towards clients.
2241 Default for tos: 0xFF (TOS from server is not changed).
2242 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2244 All of these features require the --enable-zph-qos compilation flag
2245 (enabled by default). Netfilter marking also requires the
2246 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2247 libcap 2.09+ (--with-libcap).
2251 NAME: tcp_outgoing_address
2254 DEFAULT_DOC: Address selection is performed by the operating system.
2255 LOC: Config.accessList.outgoing_address
2257 Allows you to map requests to different outgoing IP addresses
2258 based on the username or source address of the user making
2261 tcp_outgoing_address ipaddr [[!]aclname] ...
2264 Forwarding clients with dedicated IPs for certain subnets.
2266 acl normal_service_net src 10.0.0.0/24
2267 acl good_service_net src 10.0.2.0/24
2269 tcp_outgoing_address 2001:db8::c001 good_service_net
2270 tcp_outgoing_address 10.1.0.2 good_service_net
2272 tcp_outgoing_address 2001:db8::beef normal_service_net
2273 tcp_outgoing_address 10.1.0.1 normal_service_net
2275 tcp_outgoing_address 2001:db8::1
2276 tcp_outgoing_address 10.1.0.3
2278 Processing proceeds in the order specified, and stops at first fully
2281 Squid will add an implicit IP version test to each line.
2282 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2283 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2286 NOTE: The use of this directive using client dependent ACLs is
2287 incompatible with the use of server side persistent connections. To
2288 ensure correct results it is best to set server_persistent_connections
2289 to off when using this directive in such configurations.
2291 NOTE: The use of this directive to set a local IP on outgoing TCP links
2292 is incompatible with using TPROXY to set client IP out outbound TCP links.
2293 When needing to contact peers use the no-tproxy cache_peer option and the
2294 client_dst_passthru directive re-enable normal forwarding such as this.
2298 NAME: host_verify_strict
2301 LOC: Config.onoff.hostStrictVerify
2303 Regardless of this option setting, when dealing with intercepted
2304 traffic, Squid always verifies that the destination IP address matches
2305 the Host header domain or IP (called 'authority form URL').
2307 This enforcement is performed to satisfy a MUST-level requirement in
2308 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2309 authority of the origin server or gateway given by the original URL".
2312 Squid always responds with an HTTP 409 (Conflict) error
2313 page and logs a security warning if there is no match.
2315 Squid verifies that the destination IP address matches
2316 the Host header for forward-proxy and reverse-proxy traffic
2317 as well. For those traffic types, Squid also enables the
2318 following checks, comparing the corresponding Host header
2319 and Request-URI components:
2321 * The host names (domain or IP) must be identical,
2322 but valueless or missing Host header disables all checks.
2323 For the two host names to match, both must be either IP
2326 * Port numbers must be identical, but if a port is missing
2327 the scheme-default port is assumed.
2330 When set to OFF (the default):
2331 Squid allows suspicious requests to continue but logs a
2332 security warning and blocks caching of the response.
2334 * Forward-proxy traffic is not checked at all.
2336 * Reverse-proxy traffic is not checked at all.
2338 * Intercepted traffic which passes verification is handled
2339 according to client_dst_passthru.
2341 * Intercepted requests which fail verification are sent
2342 to the client original destination instead of DIRECT.
2343 This overrides 'client_dst_passthru off'.
2345 For now suspicious intercepted CONNECT requests are always
2346 responded to with an HTTP 409 (Conflict) error page.
2351 As described in CVE-2009-0801 when the Host: header alone is used
2352 to determine the destination of a request it becomes trivial for
2353 malicious scripts on remote websites to bypass browser same-origin
2354 security policy and sandboxing protections.
2356 The cause of this is that such applets are allowed to perform their
2357 own HTTP stack, in which case the same-origin policy of the browser
2358 sandbox only verifies that the applet tries to contact the same IP
2359 as from where it was loaded at the IP level. The Host: header may
2360 be different from the connected IP and approved origin.
2364 NAME: client_dst_passthru
2367 LOC: Config.onoff.client_dst_passthru
2369 With NAT or TPROXY intercepted traffic Squid may pass the request
2370 directly to the original client destination IP or seek a faster
2371 source using the HTTP Host header.
2373 Using Host to locate alternative servers can provide faster
2374 connectivity with a range of failure recovery options.
2375 But can also lead to connectivity trouble when the client and
2376 server are attempting stateful interactions unaware of the proxy.
2378 This option (on by default) prevents alternative DNS entries being
2379 located to send intercepted traffic DIRECT to an origin server.
2380 The clients original destination IP and port will be used instead.
2382 Regardless of this option setting, when dealing with intercepted
2383 traffic Squid will verify the Host: header and any traffic which
2384 fails Host verification will be treated as if this option were ON.
2386 see host_verify_strict for details on the verification process.
2391 -----------------------------------------------------------------------------
2394 NAME: ssl_unclean_shutdown
2398 LOC: Config.SSL.unclean_shutdown
2400 Some browsers (especially MSIE) bugs out on SSL shutdown
2407 LOC: Config.SSL.ssl_engine
2410 The OpenSSL engine to use. You will need to set this if you
2411 would like to use hardware SSL acceleration for example.
2414 NAME: sslproxy_client_certificate
2417 LOC: Config.ssl_client.cert
2420 Client SSL Certificate to use when proxying https:// URLs
2423 NAME: sslproxy_client_key
2426 LOC: Config.ssl_client.key
2429 Client SSL Key to use when proxying https:// URLs
2432 NAME: sslproxy_version
2435 DEFAULT_DOC: automatic SSL/TLS version negotiation
2436 LOC: Config.ssl_client.version
2439 SSL version level to use when proxying https:// URLs
2441 The versions of SSL/TLS supported:
2443 1 automatic (default)
2450 NAME: sslproxy_options
2453 LOC: Config.ssl_client.options
2456 SSL implementation options to use when proxying https:// URLs
2458 The most important being:
2460 NO_SSLv3 Disallow the use of SSLv3
2461 NO_TLSv1 Disallow the use of TLSv1.0
2462 NO_TLSv1_1 Disallow the use of TLSv1.1
2463 NO_TLSv1_2 Disallow the use of TLSv1.2
2465 Always create a new key when using temporary/ephemeral
2468 Disable use of RFC5077 session tickets. Some servers
2469 may have problems understanding the TLS extension due
2470 to ambiguous specification in RFC4507.
2471 ALL Enable various bug workarounds suggested as "harmless"
2472 by OpenSSL. Be warned that this may reduce SSL/TLS
2473 strength to some attacks.
2475 See the OpenSSL SSL_CTX_set_options documentation for a
2476 complete list of possible options.
2479 NAME: sslproxy_cipher
2482 LOC: Config.ssl_client.cipher
2485 SSL cipher list to use when proxying https:// URLs
2487 Colon separated list of supported ciphers.
2490 NAME: sslproxy_cafile
2493 LOC: Config.ssl_client.cafile
2496 file containing CA certificates to use when verifying server
2497 certificates while proxying https:// URLs
2500 NAME: sslproxy_capath
2503 LOC: Config.ssl_client.capath
2506 directory containing CA certificates to use when verifying
2507 server certificates while proxying https:// URLs
2510 NAME: sslproxy_session_ttl
2513 LOC: Config.SSL.session_ttl
2516 Sets the timeout value for SSL sessions
2519 NAME: sslproxy_session_cache_size
2522 LOC: Config.SSL.sessionCacheSize
2525 Sets the cache size to use for ssl session
2528 NAME: sslproxy_cert_sign_hash
2531 LOC: Config.SSL.certSignHash
2534 Sets the hashing algorithm to use when signing generated certificates.
2535 Valid algorithm names depend on the OpenSSL library used. The following
2536 names are usually available: sha1, sha256, sha512, and md5. Please see
2537 your OpenSSL library manual for the available hashes. By default, Squids
2538 that support this option use sha256 hashes.
2540 Squid does not forcefully purge cached certificates that were generated
2541 with an algorithm other than the currently configured one. They remain
2542 in the cache, subject to the regular cache eviction policy, and become
2543 useful if the algorithm changes again.
2548 TYPE: sslproxy_ssl_bump
2549 LOC: Config.accessList.ssl_bump
2550 DEFAULT_DOC: Become a TCP tunnel without decrypting proxied traffic.
2553 This option is consulted when a CONNECT request is received on
2554 an http_port (or a new connection is intercepted at an
2555 https_port), provided that port was configured with an ssl-bump
2556 flag. The subsequent data on the connection is either treated as
2557 HTTPS and decrypted OR tunneled at TCP level without decryption,
2558 depending on the first matching bumping "action".
2560 ssl_bump <action> [!]acl ...
2562 The following bumping actions are currently supported:
2565 Become a TCP tunnel without decrypting proxied traffic.
2566 This is the default action.
2569 Establish a secure connection with the server and, using a
2570 mimicked server certificate, with the client.
2573 Receive client (step SslBump1) or server (step SslBump2)
2574 certificate while preserving the possibility of splicing the
2575 connection. Peeking at the server certificate (during step 2)
2576 usually precludes bumping of the connection at step 3.
2579 Receive client (step SslBump1) or server (step SslBump2)
2580 certificate while preserving the possibility of bumping the
2581 connection. Staring at the server certificate (during step 2)
2582 usually precludes splicing of the connection at step 3.
2585 Close client and server connections.
2587 Backward compatibility actions available at step SslBump1:
2590 Bump the connection. Establish a secure connection with the
2591 client first, then connect to the server. This old mode does
2592 not allow Squid to mimic server SSL certificate and does not
2593 work with intercepted SSL connections.
2596 Bump the connection. Establish a secure connection with the
2597 server first, then establish a secure connection with the
2598 client, using a mimicked server certificate. Works with both
2599 CONNECT requests and intercepted SSL connections, but does
2600 not allow to make decisions based on SSL handshake info.
2603 Decide whether to bump or splice the connection based on
2604 client-to-squid and server-to-squid SSL hello messages.
2608 Same as the "splice" action.
2610 All ssl_bump rules are evaluated at each of the supported bumping
2611 steps. Rules with actions that are impossible at the current step are
2612 ignored. The first matching ssl_bump action wins and is applied at the
2613 end of the current step. If no rules match, the splice action is used.
2614 See the at_step ACL for a list of the supported SslBump steps.
2616 This clause supports both fast and slow acl types.
2617 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2619 See also: http_port ssl-bump, https_port ssl-bump, and acl at_step.
2622 # Example: Bump all requests except those originating from
2623 # localhost or those going to example.com.
2625 acl broken_sites dstdomain .example.com
2626 ssl_bump splice localhost
2627 ssl_bump splice broken_sites
2631 NAME: sslproxy_flags
2634 LOC: Config.ssl_client.flags
2637 Various flags modifying the use of SSL while proxying https:// URLs:
2638 DONT_VERIFY_PEER Accept certificates that fail verification.
2639 For refined control, see sslproxy_cert_error.
2640 NO_DEFAULT_CA Don't use the default CA list built in
2644 NAME: sslproxy_cert_error
2647 DEFAULT_DOC: Server certificate errors terminate the transaction.
2648 LOC: Config.ssl_client.cert_error
2651 Use this ACL to bypass server certificate validation errors.
2653 For example, the following lines will bypass all validation errors
2654 when talking to servers for example.com. All other
2655 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2657 acl BrokenButTrustedServers dstdomain example.com
2658 sslproxy_cert_error allow BrokenButTrustedServers
2659 sslproxy_cert_error deny all
2661 This clause only supports fast acl types.
2662 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2663 Using slow acl types may result in server crashes
2665 Without this option, all server certificate validation errors
2666 terminate the transaction to protect Squid and the client.
2668 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2669 but should not happen unless your OpenSSL library is buggy.
2672 Bypassing validation errors is dangerous because an
2673 error usually implies that the server cannot be trusted
2674 and the connection may be insecure.
2676 See also: sslproxy_flags and DONT_VERIFY_PEER.
2679 NAME: sslproxy_cert_sign
2682 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2683 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2684 POSTSCRIPTUM: signTrusted all
2685 TYPE: sslproxy_cert_sign
2686 LOC: Config.ssl_client.cert_sign
2689 sslproxy_cert_sign <signing algorithm> acl ...
2691 The following certificate signing algorithms are supported:
2694 Sign using the configured CA certificate which is usually
2695 placed in and trusted by end-user browsers. This is the
2696 default for trusted origin server certificates.
2699 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2700 This is the default for untrusted origin server certificates
2701 that are not self-signed (see ssl::certUntrusted).
2704 Sign using a self-signed certificate with the right CN to
2705 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2706 browser. This is the default for self-signed origin server
2707 certificates (see ssl::certSelfSigned).
2709 This clause only supports fast acl types.
2711 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2712 signing algorithm to generate the certificate and ignores all
2713 subsequent sslproxy_cert_sign options (the first match wins). If no
2714 acl(s) match, the default signing algorithm is determined by errors
2715 detected when obtaining and validating the origin server certificate.
2717 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2718 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2719 CONNECT request that carries a domain name. In all other cases (CONNECT
2720 to an IP address or an intercepted SSL connection), Squid cannot detect
2721 the domain mismatch at certificate generation time when
2722 bump-server-first is used.
2725 NAME: sslproxy_cert_adapt
2728 TYPE: sslproxy_cert_adapt
2729 LOC: Config.ssl_client.cert_adapt
2732 sslproxy_cert_adapt <adaptation algorithm> acl ...
2734 The following certificate adaptation algorithms are supported:
2737 Sets the "Not After" property to the "Not After" property of
2738 the CA certificate used to sign generated certificates.
2741 Sets the "Not Before" property to the "Not Before" property of
2742 the CA certificate used to sign generated certificates.
2744 setCommonName or setCommonName{CN}
2745 Sets Subject.CN property to the host name specified as a
2746 CN parameter or, if no explicit CN parameter was specified,
2747 extracted from the CONNECT request. It is a misconfiguration
2748 to use setCommonName without an explicit parameter for
2749 intercepted or tproxied SSL connections.
2751 This clause only supports fast acl types.
2753 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2754 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2755 corresponding adaptation algorithm to generate the certificate and
2756 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2757 group (i.e., the first match wins within each algorithm group). If no
2758 acl(s) match, the default mimicking action takes place.
2760 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2761 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2762 CONNECT request that carries a domain name. In all other cases (CONNECT
2763 to an IP address or an intercepted SSL connection), Squid cannot detect
2764 the domain mismatch at certificate generation time when
2765 bump-server-first is used.
2768 NAME: sslpassword_program
2771 LOC: Config.Program.ssl_password
2774 Specify a program used for entering SSL key passphrases
2775 when using encrypted SSL certificate keys. If not specified
2776 keys must either be unencrypted, or Squid started with the -N
2777 option to allow it to query interactively for the passphrase.
2779 The key file name is given as argument to the program allowing
2780 selection of the right password if you have multiple encrypted
2785 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2786 -----------------------------------------------------------------------------
2789 NAME: sslcrtd_program
2792 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2793 LOC: Ssl::TheConfig.ssl_crtd
2795 Specify the location and options of the executable for ssl_crtd process.
2796 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2797 For more information use:
2798 @DEFAULT_SSL_CRTD@ -h
2801 NAME: sslcrtd_children
2802 TYPE: HelperChildConfig
2804 DEFAULT: 32 startup=5 idle=1
2805 LOC: Ssl::TheConfig.ssl_crtdChildren
2807 The maximum number of processes spawn to service ssl server.
2808 The maximum this may be safely set to is 32.
2810 The startup= and idle= options allow some measure of skew in your
2815 Sets the minimum number of processes to spawn when Squid
2816 starts or reconfigures. When set to zero the first request will
2817 cause spawning of the first child process to handle it.
2819 Starting too few children temporary slows Squid under load while it
2820 tries to spawn enough additional processes to cope with traffic.
2824 Sets a minimum of how many processes Squid is to try and keep available
2825 at all times. When traffic begins to rise above what the existing
2826 processes can handle this many more will be spawned up to the maximum
2827 configured. A minimum setting of 1 is required.
2831 Sets the maximum number of queued requests.
2832 If the queued requests exceed queue size for more than 3 minutes
2833 squid aborts its operation.
2834 The default value is set to 2*numberofchildren.
2836 You must have at least one ssl_crtd process.
2839 NAME: sslcrtvalidator_program
2843 LOC: Ssl::TheConfig.ssl_crt_validator
2845 Specify the location and options of the executable for ssl_crt_validator
2848 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
2851 ttl=n TTL in seconds for cached results. The default is 60 secs
2852 cache=n limit the result cache size. The default value is 2048
2855 NAME: sslcrtvalidator_children
2856 TYPE: HelperChildConfig
2858 DEFAULT: 32 startup=5 idle=1 concurrency=1
2859 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2861 The maximum number of processes spawn to service SSL server.
2862 The maximum this may be safely set to is 32.
2864 The startup= and idle= options allow some measure of skew in your
2869 Sets the minimum number of processes to spawn when Squid
2870 starts or reconfigures. When set to zero the first request will
2871 cause spawning of the first child process to handle it.
2873 Starting too few children temporary slows Squid under load while it
2874 tries to spawn enough additional processes to cope with traffic.
2878 Sets a minimum of how many processes Squid is to try and keep available
2879 at all times. When traffic begins to rise above what the existing
2880 processes can handle this many more will be spawned up to the maximum
2881 configured. A minimum setting of 1 is required.
2885 The number of requests each certificate validator helper can handle in
2886 parallel. A value of 0 indicates the certficate validator does not
2887 support concurrency. Defaults to 1.
2889 When this directive is set to a value >= 1 then the protocol
2890 used to communicate with the helper is modified to include
2891 a request ID in front of the request/response. The request
2892 ID from the request must be echoed back with the response
2897 Sets the maximum number of queued requests.
2898 If the queued requests exceed queue size for more than 3 minutes
2899 squid aborts its operation.
2900 The default value is set to 2*numberofchildren.
2902 You must have at least one ssl_crt_validator process.
2906 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2907 -----------------------------------------------------------------------------
2915 To specify other caches in a hierarchy, use the format:
2917 cache_peer hostname type http-port icp-port [options]
2922 # hostname type port port options
2923 # -------------------- -------- ----- ----- -----------
2924 cache_peer parent.foo.net parent 3128 3130 default
2925 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2926 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2927 cache_peer example.com parent 80 0 default
2928 cache_peer cdn.example.com sibling 3128 0
2930 type: either 'parent', 'sibling', or 'multicast'.
2932 proxy-port: The port number where the peer accept HTTP requests.
2933 For other Squid proxies this is usually 3128
2934 For web servers this is usually 80
2936 icp-port: Used for querying neighbor caches about objects.
2937 Set to 0 if the peer does not support ICP or HTCP.
2938 See ICP and HTCP options below for additional details.
2941 ==== ICP OPTIONS ====
2943 You MUST also set icp_port and icp_access explicitly when using these options.
2944 The defaults will prevent peer traffic using ICP.
2947 no-query Disable ICP queries to this neighbor.
2950 Indicates the named peer is a member of a multicast group.
2951 ICP queries will not be sent directly to the peer, but ICP
2952 replies will be accepted from it.
2954 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2955 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2958 To only send ICP queries to this neighbor infrequently.
2959 This is used to keep the neighbor round trip time updated
2960 and is usually used in conjunction with weighted-round-robin.
2963 ==== HTCP OPTIONS ====
2965 You MUST also set htcp_port and htcp_access explicitly when using these options.
2966 The defaults will prevent peer traffic using HTCP.
2969 htcp Send HTCP, instead of ICP, queries to the neighbor.
2970 You probably also want to set the "icp-port" to 4827
2971 instead of 3130. This directive accepts a comma separated
2972 list of options described below.
2974 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2976 htcp=no-clr Send HTCP to the neighbor but without
2977 sending any CLR requests. This cannot be used with
2980 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2981 This cannot be used with no-clr.
2984 Send HTCP to the neighbor including CLRs but only when
2985 they do not result from PURGE requests.
2988 Forward any HTCP CLR requests this proxy receives to the peer.
2991 ==== PEER SELECTION METHODS ====
2993 The default peer selection method is ICP, with the first responding peer
2994 being used as source. These options can be used for better load balancing.
2997 default This is a parent cache which can be used as a "last-resort"
2998 if a peer cannot be located by any of the peer-selection methods.
2999 If specified more than once, only the first is used.
3001 round-robin Load-Balance parents which should be used in a round-robin
3002 fashion in the absence of any ICP queries.
3003 weight=N can be used to add bias.
3005 weighted-round-robin
3006 Load-Balance parents which should be used in a round-robin
3007 fashion with the frequency of each parent being based on the
3008 round trip time. Closer parents are used more often.
3009 Usually used for background-ping parents.
3010 weight=N can be used to add bias.
3012 carp Load-Balance parents which should be used as a CARP array.
3013 The requests will be distributed among the parents based on the
3014 CARP load balancing hash function based on their weight.
3016 userhash Load-balance parents based on the client proxy_auth or ident username.
3018 sourcehash Load-balance parents based on the client source IP.
3021 To be used only for cache peers of type "multicast".
3022 ALL members of this multicast group have "sibling"
3023 relationship with it, not "parent". This is to a multicast
3024 group when the requested object would be fetched only from
3025 a "parent" cache, anyway. It's useful, e.g., when
3026 configuring a pool of redundant Squid proxies, being
3027 members of the same multicast group.
3030 ==== PEER SELECTION OPTIONS ====
3032 weight=N use to affect the selection of a peer during any weighted
3033 peer-selection mechanisms.
3034 The weight must be an integer; default is 1,
3035 larger weights are favored more.
3036 This option does not affect parent selection if a peering
3037 protocol is not in use.
3039 basetime=N Specify a base amount to be subtracted from round trip
3041 It is subtracted before division by weight in calculating
3042 which parent to fectch from. If the rtt is less than the
3043 base time the rtt is set to a minimal value.
3045 ttl=N Specify a TTL to use when sending multicast ICP queries
3047 Only useful when sending to a multicast group.
3048 Because we don't accept ICP replies from random
3049 hosts, you must configure other group members as
3050 peers with the 'multicast-responder' option.
3052 no-delay To prevent access to this neighbor from influencing the
3055 digest-url=URL Tell Squid to fetch the cache digest (if digests are
3056 enabled) for this host from the specified URL rather
3057 than the Squid default location.
3060 ==== CARP OPTIONS ====
3062 carp-key=key-specification
3063 use a different key than the full URL to hash against the peer.
3064 the key-specification is a comma-separated list of the keywords
3065 scheme, host, port, path, params
3066 Order is not important.
3068 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
3070 originserver Causes this parent to be contacted as an origin server.
3071 Meant to be used in accelerator setups when the peer
3075 Set the Host header of requests forwarded to this peer.
3076 Useful in accelerator setups where the server (peer)
3077 expects a certain domain name but clients may request
3078 others. ie example.com or www.example.com
3080 no-digest Disable request of cache digests.
3083 Disables requesting ICMP RTT database (NetDB).
3086 ==== AUTHENTICATION OPTIONS ====
3089 If this is a personal/workgroup proxy and your parent
3090 requires proxy authentication.
3092 Note: The string can include URL escapes (i.e. %20 for
3093 spaces). This also means % must be written as %%.
3096 Send login details received from client to this peer.
3097 Both Proxy- and WWW-Authorization headers are passed
3098 without alteration to the peer.
3099 Authentication is not required by Squid for this to work.
3101 Note: This will pass any form of authentication but
3102 only Basic auth will work through a proxy unless the
3103 connection-auth options are also used.
3105 login=PASS Send login details received from client to this peer.
3106 Authentication is not required by this option.
3108 If there are no client-provided authentication headers
3109 to pass on, but username and password are available
3110 from an external ACL user= and password= result tags
3111 they may be sent instead.
3113 Note: To combine this with proxy_auth both proxies must
3114 share the same user database as HTTP only allows for
3115 a single login (one for proxy, one for origin server).
3116 Also be warned this will expose your users proxy
3117 password to the peer. USE WITH CAUTION
3120 Send the username to the upstream cache, but with a
3121 fixed password. This is meant to be used when the peer
3122 is in another administrative domain, but it is still
3123 needed to identify each user.
3124 The star can optionally be followed by some extra
3125 information which is added to the username. This can
3126 be used to identify this proxy to the peer, similar to
3127 the login=username:password option above.
3130 If this is a personal/workgroup proxy and your parent
3131 requires a secure proxy authentication.
3132 The first principal from the default keytab or defined by
3133 the environment variable KRB5_KTNAME will be used.
3135 WARNING: The connection may transmit requests from multiple
3136 clients. Negotiate often assumes end-to-end authentication
3137 and a single-client. Which is not strictly true here.
3139 login=NEGOTIATE:principal_name
3140 If this is a personal/workgroup proxy and your parent
3141 requires a secure proxy authentication.
3142 The principal principal_name from the default keytab or
3143 defined by the environment variable KRB5_KTNAME will be
3146 WARNING: The connection may transmit requests from multiple
3147 clients. Negotiate often assumes end-to-end authentication
3148 and a single-client. Which is not strictly true here.
3150 connection-auth=on|off
3151 Tell Squid that this peer does or not support Microsoft
3152 connection oriented authentication, and any such
3153 challenges received from there should be ignored.
3154 Default is auto to automatically determine the status
3158 ==== SSL / HTTPS / TLS OPTIONS ====
3160 ssl Encrypt connections to this peer with SSL/TLS.
3162 sslcert=/path/to/ssl/certificate
3163 A client SSL certificate to use when connecting to
3166 sslkey=/path/to/ssl/key
3167 The private SSL key corresponding to sslcert above.
3168 If 'sslkey' is not specified 'sslcert' is assumed to
3169 reference a combined file containing both the
3170 certificate and the key.
3172 sslversion=1|3|4|5|6
3173 The SSL version to use when connecting to this peer
3174 1 = automatic (default)
3180 sslcipher=... The list of valid SSL ciphers to use when connecting
3183 ssloptions=... Specify various SSL implementation options:
3185 NO_SSLv3 Disallow the use of SSLv3
3186 NO_TLSv1 Disallow the use of TLSv1.0
3187 NO_TLSv1_1 Disallow the use of TLSv1.1
3188 NO_TLSv1_2 Disallow the use of TLSv1.2
3190 Always create a new key when using
3191 temporary/ephemeral DH key exchanges
3192 ALL Enable various bug workarounds
3193 suggested as "harmless" by OpenSSL
3194 Be warned that this reduces SSL/TLS
3195 strength to some attacks.
3197 See the OpenSSL SSL_CTX_set_options documentation for a
3200 sslcafile=... A file containing additional CA certificates to use
3201 when verifying the peer certificate.
3203 sslcapath=... A directory containing additional CA certificates to
3204 use when verifying the peer certificate.
3206 sslcrlfile=... A certificate revocation list file to use when
3207 verifying the peer certificate.
3209 sslflags=... Specify various flags modifying the SSL implementation:
3212 Accept certificates even if they fail to
3215 Don't use the default CA list built in
3218 Don't verify the peer certificate
3219 matches the server name
3221 ssldomain= The peer name as advertised in it's certificate.
3222 Used for verifying the correctness of the received peer
3223 certificate. If not specified the peer hostname will be
3227 Enable the "Front-End-Https: On" header needed when
3228 using Squid as a SSL frontend in front of Microsoft OWA.
3229 See MS KB document Q307347 for details on this header.
3230 If set to auto the header will only be added if the
3231 request is forwarded as a https:// URL.
3234 ==== GENERAL OPTIONS ====
3237 A peer-specific connect timeout.
3238 Also see the peer_connect_timeout directive.
3240 connect-fail-limit=N
3241 How many times connecting to a peer must fail before
3242 it is marked as down. Standby connection failures
3243 count towards this limit. Default is 10.
3245 allow-miss Disable Squid's use of only-if-cached when forwarding
3246 requests to siblings. This is primarily useful when
3247 icp_hit_stale is used by the sibling. To extensive use
3248 of this option may result in forwarding loops, and you
3249 should avoid having two-way peerings with this option.
3250 For example to deny peer usage on requests from peer
3251 by denying cache_peer_access if the source is a peer.
3253 max-conn=N Limit the number of concurrent connections the Squid
3254 may open to this peer, including already opened idle
3255 and standby connections. There is no peer-specific
3256 connection limit by default.
3258 A peer exceeding the limit is not used for new
3259 requests unless a standby connection is available.
3261 max-conn currently works poorly with idle persistent
3262 connections: When a peer reaches its max-conn limit,
3263 and there are idle persistent connections to the peer,
3264 the peer may not be selected because the limiting code
3265 does not know whether Squid can reuse those idle
3268 standby=N Maintain a pool of N "hot standby" connections to an
3269 UP peer, available for requests when no idle
3270 persistent connection is available (or safe) to use.
3271 By default and with zero N, no such pool is maintained.
3272 N must not exceed the max-conn limit (if any).
3274 At start or after reconfiguration, Squid opens new TCP
3275 standby connections until there are N connections
3276 available and then replenishes the standby pool as
3277 opened connections are used up for requests. A used
3278 connection never goes back to the standby pool, but
3279 may go to the regular idle persistent connection pool
3280 shared by all peers and origin servers.
3282 Squid never opens multiple new standby connections
3283 concurrently. This one-at-a-time approach minimizes
3284 flooding-like effect on peers. Furthermore, just a few
3285 standby connections should be sufficient in most cases
3286 to supply most new requests with a ready-to-use
3289 Standby connections obey server_idle_pconn_timeout.
3290 For the feature to work as intended, the peer must be
3291 configured to accept and keep them open longer than
3292 the idle timeout at the connecting Squid, to minimize
3293 race conditions typical to idle used persistent
3294 connections. Default request_timeout and
3295 server_idle_pconn_timeout values ensure such a
3298 name=xxx Unique name for the peer.
3299 Required if you have multiple peers on the same host
3300 but different ports.
3301 This name can be used in cache_peer_access and similar
3302 directives to dentify the peer.
3303 Can be used by outgoing access controls through the
3306 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3307 requests to this peer. Use normal address selection instead.
3308 This overrides the spoof_client_ip ACL.
3310 proxy-only objects fetched from the peer will not be stored locally.
3314 NAME: cache_peer_domain cache_host_domain
3319 Use to limit the domains for which a neighbor cache will be
3323 cache_peer_domain cache-host domain [domain ...]
3324 cache_peer_domain cache-host !domain
3326 For example, specifying
3328 cache_peer_domain parent.foo.net .edu
3330 has the effect such that UDP query packets are sent to
3331 'bigserver' only when the requested object exists on a
3332 server in the .edu domain. Prefixing the domainname
3333 with '!' means the cache will be queried for objects
3336 NOTE: * Any number of domains may be given for a cache-host,
3337 either on the same or separate lines.
3338 * When multiple domains are given for a particular
3339 cache-host, the first matched domain is applied.
3340 * Cache hosts with no domain restrictions are queried
3342 * There are no defaults.
3343 * There is also a 'cache_peer_access' tag in the ACL
3347 NAME: cache_peer_access
3352 Similar to 'cache_peer_domain' but provides more flexibility by
3356 cache_peer_access cache-host allow|deny [!]aclname ...
3358 The syntax is identical to 'http_access' and the other lists of
3359 ACL elements. See the comments for 'http_access' below, or
3360 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
3363 NAME: neighbor_type_domain
3364 TYPE: hostdomaintype
3366 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3369 Modify the cache_peer neighbor type when passing requests
3370 about specific domains to the peer.
3373 neighbor_type_domain neighbor parent|sibling domain domain ...
3376 cache_peer foo.example.com parent 3128 3130
3377 neighbor_type_domain foo.example.com sibling .au .de
3379 The above configuration treats all requests to foo.example.com as a
3380 parent proxy unless the request is for a .au or .de ccTLD domain name.
3383 NAME: dead_peer_timeout
3387 LOC: Config.Timeout.deadPeer
3389 This controls how long Squid waits to declare a peer cache
3390 as "dead." If there are no ICP replies received in this
3391 amount of time, Squid will declare the peer dead and not
3392 expect to receive any further ICP replies. However, it
3393 continues to send ICP queries, and will mark the peer as
3394 alive upon receipt of the first subsequent ICP reply.
3396 This timeout also affects when Squid expects to receive ICP
3397 replies from peers. If more than 'dead_peer' seconds have
3398 passed since the last ICP reply was received, Squid will not
3399 expect to receive an ICP reply on the next query. Thus, if
3400 your time between requests is greater than this timeout, you
3401 will see a lot of requests sent DIRECT to origin servers
3402 instead of to your parents.
3405 NAME: forward_max_tries
3408 LOC: Config.forward_max_tries
3410 Controls how many different forward paths Squid will try
3411 before giving up. See also forward_timeout.
3413 NOTE: connect_retries (default: none) can make each of these
3414 possible forwarding paths be tried multiple times.
3418 MEMORY CACHE OPTIONS
3419 -----------------------------------------------------------------------------
3426 LOC: Config.memMaxSize
3428 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3429 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3430 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3431 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3433 'cache_mem' specifies the ideal amount of memory to be used
3435 * In-Transit objects
3437 * Negative-Cached objects
3439 Data for these objects are stored in 4 KB blocks. This
3440 parameter specifies the ideal upper limit on the total size of
3441 4 KB blocks allocated. In-Transit objects take the highest
3444 In-transit objects have priority over the others. When
3445 additional space is needed for incoming data, negative-cached
3446 and hot objects will be released. In other words, the
3447 negative-cached and hot objects will fill up any unused space
3448 not needed for in-transit objects.
3450 If circumstances require, this limit will be exceeded.
3451 Specifically, if your incoming request rate requires more than
3452 'cache_mem' of memory to hold in-transit objects, Squid will
3453 exceed this limit to satisfy the new requests. When the load
3454 decreases, blocks will be freed until the high-water mark is
3455 reached. Thereafter, blocks will be used to store hot
3458 If shared memory caching is enabled, Squid does not use the shared
3459 cache space for in-transit objects, but they still consume as much
3460 local memory as they need. For more details about the shared memory
3461 cache, see memory_cache_shared.
3464 NAME: maximum_object_size_in_memory
3468 LOC: Config.Store.maxInMemObjSize
3470 Objects greater than this size will not be attempted to kept in
3471 the memory cache. This should be set high enough to keep objects
3472 accessed frequently in memory to improve performance whilst low
3473 enough to keep larger objects from hoarding cache_mem.
3476 NAME: memory_cache_shared
3479 LOC: Config.memShared
3481 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3483 Controls whether the memory cache is shared among SMP workers.
3485 The shared memory cache is meant to occupy cache_mem bytes and replace
3486 the non-shared memory cache, although some entities may still be
3487 cached locally by workers for now (e.g., internal and in-transit
3488 objects may be served from a local memory cache even if shared memory
3489 caching is enabled).
3491 By default, the memory cache is shared if and only if all of the
3492 following conditions are satisfied: Squid runs in SMP mode with
3493 multiple workers, cache_mem is positive, and Squid environment
3494 supports required IPC primitives (e.g., POSIX shared memory segments
3495 and GCC-style atomic operations).
3497 To avoid blocking locks, shared memory uses opportunistic algorithms
3498 that do not guarantee that every cachable entity that could have been
3499 shared among SMP workers will actually be shared.
3501 Currently, entities exceeding 32KB in size cannot be shared.
3504 NAME: memory_cache_mode
3508 DEFAULT_DOC: Keep the most recently fetched objects in memory
3510 Controls which objects to keep in the memory cache (cache_mem)
3512 always Keep most recently fetched objects in memory (default)
3514 disk Only disk cache hits are kept in memory, which means
3515 an object must first be cached on disk and then hit
3516 a second time before cached in memory.
3518 network Only objects fetched from network is kept in memory
3521 NAME: memory_replacement_policy
3523 LOC: Config.memPolicy
3526 The memory replacement policy parameter determines which
3527 objects are purged from memory when memory space is needed.
3529 See cache_replacement_policy for details on algorithms.
3534 -----------------------------------------------------------------------------
3537 NAME: cache_replacement_policy
3539 LOC: Config.replPolicy
3542 The cache replacement policy parameter determines which
3543 objects are evicted (replaced) when disk space is needed.
3545 lru : Squid's original list based LRU policy
3546 heap GDSF : Greedy-Dual Size Frequency
3547 heap LFUDA: Least Frequently Used with Dynamic Aging
3548 heap LRU : LRU policy implemented using a heap
3550 Applies to any cache_dir lines listed below this directive.
3552 The LRU policies keeps recently referenced objects.
3554 The heap GDSF policy optimizes object hit rate by keeping smaller
3555 popular objects in cache so it has a better chance of getting a
3556 hit. It achieves a lower byte hit rate than LFUDA though since
3557 it evicts larger (possibly popular) objects.
3559 The heap LFUDA policy keeps popular objects in cache regardless of
3560 their size and thus optimizes byte hit rate at the expense of
3561 hit rate since one large, popular object will prevent many
3562 smaller, slightly less popular objects from being cached.
3564 Both policies utilize a dynamic aging mechanism that prevents
3565 cache pollution that can otherwise occur with frequency-based
3566 replacement policies.
3568 NOTE: if using the LFUDA replacement policy you should increase
3569 the value of maximum_object_size above its default of 4 MB to
3570 to maximize the potential byte hit rate improvement of LFUDA.
3572 For more information about the GDSF and LFUDA cache replacement
3573 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3574 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3577 NAME: minimum_object_size
3581 DEFAULT_DOC: no limit
3582 LOC: Config.Store.minObjectSize
3584 Objects smaller than this size will NOT be saved on disk. The
3585 value is specified in bytes, and the default is 0 KB, which
3586 means all responses can be stored.
3589 NAME: maximum_object_size
3593 LOC: Config.Store.maxObjectSize
3595 Set the default value for max-size parameter on any cache_dir.
3596 The value is specified in bytes, and the default is 4 MB.
3598 If you wish to get a high BYTES hit ratio, you should probably
3599 increase this (one 32 MB object hit counts for 3200 10KB
3602 If you wish to increase hit ratio more than you want to
3603 save bandwidth you should leave this low.
3605 NOTE: if using the LFUDA replacement policy you should increase
3606 this value to maximize the byte hit rate improvement of LFUDA!
3607 See cache_replacement_policy for a discussion of this policy.
3613 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3614 LOC: Config.cacheSwap
3617 cache_dir Type Directory-Name Fs-specific-data [options]
3619 You can specify multiple cache_dir lines to spread the
3620 cache among different disk partitions.
3622 Type specifies the kind of storage system to use. Only "ufs"
3623 is built by default. To enable any of the other storage systems
3624 see the --enable-storeio configure option.
3626 'Directory' is a top-level directory where cache swap
3627 files will be stored. If you want to use an entire disk
3628 for caching, this can be the mount-point directory.
3629 The directory must exist and be writable by the Squid
3630 process. Squid will NOT create this directory for you.
3632 In SMP configurations, cache_dir must not precede the workers option
3633 and should use configuration macros or conditionals to give each
3634 worker interested in disk caching a dedicated cache directory.
3637 ==== The ufs store type ====
3639 "ufs" is the old well-known Squid storage format that has always
3643 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3645 'Mbytes' is the amount of disk space (MB) to use under this
3646 directory. The default is 100 MB. Change this to suit your
3647 configuration. Do NOT put the size of your disk drive here.
3648 Instead, if you want Squid to use the entire disk drive,
3649 subtract 20% and use that value.
3651 'L1' is the number of first-level subdirectories which
3652 will be created under the 'Directory'. The default is 16.
3654 'L2' is the number of second-level subdirectories which
3655 will be created under each first-level directory. The default
3659 ==== The aufs store type ====
3661 "aufs" uses the same storage format as "ufs", utilizing
3662 POSIX-threads to avoid blocking the main Squid process on
3663 disk-I/O. This was formerly known in Squid as async-io.
3666 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3668 see argument descriptions under ufs above
3671 ==== The diskd store type ====
3673 "diskd" uses the same storage format as "ufs", utilizing a
3674 separate process to avoid blocking the main Squid process on
3678 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3680 see argument descriptions under ufs above
3682 Q1 specifies the number of unacknowledged I/O requests when Squid
3683 stops opening new files. If this many messages are in the queues,
3684 Squid won't open new files. Default is 64
3686 Q2 specifies the number of unacknowledged messages when Squid
3687 starts blocking. If this many messages are in the queues,
3688 Squid blocks until it receives some replies. Default is 72
3690 When Q1 < Q2 (the default), the cache directory is optimized
3691 for lower response time at the expense of a decrease in hit
3692 ratio. If Q1 > Q2, the cache directory is optimized for
3693 higher hit ratio at the expense of an increase in response
3697 ==== The rock store type ====
3700 cache_dir rock Directory-Name Mbytes [options]
3702 The Rock Store type is a database-style storage. All cached
3703 entries are stored in a "database" file, using fixed-size slots.
3704 A single entry occupies one or more slots.
3706 If possible, Squid using Rock Store creates a dedicated kid
3707 process called "disker" to avoid blocking Squid worker(s) on disk
3708 I/O. One disker kid is created for each rock cache_dir. Diskers
3709 are created only when Squid, running in daemon mode, has support
3710 for the IpcIo disk I/O module.
3712 swap-timeout=msec: Squid will not start writing a miss to or
3713 reading a hit from disk if it estimates that the swap operation
3714 will take more than the specified number of milliseconds. By
3715 default and when set to zero, disables the disk I/O time limit
3716 enforcement. Ignored when using blocking I/O module because
3717 blocking synchronous I/O does not allow Squid to estimate the
3718 expected swap wait time.
3720 max-swap-rate=swaps/sec: Artificially limits disk access using
3721 the specified I/O rate limit. Swap out requests that
3722 would cause the average I/O rate to exceed the limit are
3723 delayed. Individual swap in requests (i.e., hits or reads) are
3724 not delayed, but they do contribute to measured swap rate and
3725 since they are placed in the same FIFO queue as swap out
3726 requests, they may wait longer if max-swap-rate is smaller.
3727 This is necessary on file systems that buffer "too
3728 many" writes and then start blocking Squid and other processes
3729 while committing those writes to disk. Usually used together
3730 with swap-timeout to avoid excessive delays and queue overflows
3731 when disk demand exceeds available disk "bandwidth". By default
3732 and when set to zero, disables the disk I/O rate limit
3733 enforcement. Currently supported by IpcIo module only.
3735 slot-size=bytes: The size of a database "record" used for
3736 storing cached responses. A cached response occupies at least
3737 one slot and all database I/O is done using individual slots so
3738 increasing this parameter leads to more disk space waste while
3739 decreasing it leads to more disk I/O overheads. Should be a
3740 multiple of your operating system I/O page size. Defaults to
3741 16KBytes. A housekeeping header is stored with each slot and
3742 smaller slot-sizes will be rejected. The header is smaller than
3746 ==== COMMON OPTIONS ====
3748 no-store no new objects should be stored to this cache_dir.
3750 min-size=n the minimum object size in bytes this cache_dir
3751 will accept. It's used to restrict a cache_dir
3752 to only store large objects (e.g. AUFS) while
3753 other stores are optimized for smaller objects
3757 max-size=n the maximum object size in bytes this cache_dir
3759 The value in maximum_object_size directive sets
3760 the default unless more specific details are
3761 available (ie a small store capacity).
3763 Note: To make optimal use of the max-size limits you should order
3764 the cache_dir lines with the smallest max-size value first.
3768 # Uncomment and adjust the following to add a disk cache directory.
3769 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3773 NAME: store_dir_select_algorithm
3775 LOC: Config.store_dir_select_algorithm
3778 How Squid selects which cache_dir to use when the response
3779 object will fit into more than one.
3781 Regardless of which algorithm is used the cache_dir min-size
3782 and max-size parameters are obeyed. As such they can affect
3783 the selection algorithm by limiting the set of considered
3790 This algorithm is suited to caches with similar cache_dir
3791 sizes and disk speeds.
3793 The disk with the least I/O pending is selected.
3794 When there are multiple disks with the same I/O load ranking
3795 the cache_dir with most available capacity is selected.
3797 When a mix of cache_dir sizes are configured the faster disks
3798 have a naturally lower I/O loading and larger disks have more
3799 capacity. So space used to store objects and data throughput
3800 may be very unbalanced towards larger disks.
3805 This algorithm is suited to caches with unequal cache_dir
3808 Each cache_dir is selected in a rotation. The next suitable
3811 Available cache_dir capacity is only considered in relation
3812 to whether the object will fit and meets the min-size and
3813 max-size parameters.
3815 Disk I/O loading is only considered to prevent overload on slow
3816 disks. This algorithm does not spread objects by size, so any
3817 I/O loading per-disk may appear very unbalanced and volatile.
3819 If several cache_dirs use similar min-size, max-size, or other
3820 limits to to reject certain responses, then do not group such
3821 cache_dir lines together, to avoid round-robin selection bias
3822 towards the first cache_dir after the group. Instead, interleave
3823 cache_dir lines from different groups. For example:
3825 store_dir_select_algorithm round-robin
3826 cache_dir rock /hdd1 ... min-size=100000
3827 cache_dir rock /ssd1 ... max-size=99999
3828 cache_dir rock /hdd2 ... min-size=100000
3829 cache_dir rock /ssd2 ... max-size=99999
3830 cache_dir rock /hdd3 ... min-size=100000
3831 cache_dir rock /ssd3 ... max-size=99999
3834 NAME: max_open_disk_fds
3836 LOC: Config.max_open_disk_fds
3838 DEFAULT_DOC: no limit
3840 To avoid having disk as the I/O bottleneck Squid can optionally
3841 bypass the on-disk cache if more than this amount of disk file
3842 descriptors are open.
3844 A value of 0 indicates no limit.
3847 NAME: cache_swap_low
3848 COMMENT: (percent, 0-100)
3851 LOC: Config.Swap.lowWaterMark
3853 The low-water mark for cache object replacement.
3854 Replacement begins when the swap (disk) usage is above the
3855 low-water mark and attempts to maintain utilization near the
3856 low-water mark. As swap utilization gets close to high-water
3857 mark object eviction becomes more aggressive. If utilization is
3858 close to the low-water mark less replacement is done each time.
3860 Defaults are 90% and 95%. If you have a large cache, 5% could be
3861 hundreds of MB. If this is the case you may wish to set these
3862 numbers closer together.
3864 See also cache_swap_high
3867 NAME: cache_swap_high
3868 COMMENT: (percent, 0-100)
3871 LOC: Config.Swap.highWaterMark
3873 The high-water mark for cache object replacement.
3874 Replacement begins when the swap (disk) usage is above the
3875 low-water mark and attempts to maintain utilization near the
3876 low-water mark. As swap utilization gets close to high-water
3877 mark object eviction becomes more aggressive. If utilization is
3878 close to the low-water mark less replacement is done each time.
3880 Defaults are 90% and 95%. If you have a large cache, 5% could be
3881 hundreds of MB. If this is the case you may wish to set these
3882 numbers closer together.
3884 See also cache_swap_low
3889 -----------------------------------------------------------------------------
3896 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
3900 logformat <name> <format specification>
3902 Defines an access log format.
3904 The <format specification> is a string with embedded % format codes
3906 % format codes all follow the same basic structure where all but
3907 the formatcode is optional. Output strings are automatically escaped
3908 as required according to their context and the output format
3909 modifiers are usually not needed, but can be specified if an explicit
3910 output format is desired.
3912 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3914 " output in quoted string format
3915 [ output in squid text log format as used by log_mime_hdrs
3916 # output in URL quoted format
3921 width minimum and/or maximum field width:
3922 [width_min][.width_max]
3923 When minimum starts with 0, the field is zero-padded.
3924 String values exceeding maximum width are truncated.
3926 {arg} argument such as header name etc
3930 % a literal % character
3931 sn Unique sequence number per log line entry
3932 err_code The ID of an error response served by Squid or
3933 a similar internal error identifier.
3934 err_detail Additional err_code-dependent error information.
3935 note The annotation specified by the argument. Also
3936 logs the adaptation meta headers set by the
3937 adaptation_meta configuration parameter.
3938 If no argument given all annotations logged.
3939 The argument may include a separator to use with
3942 By default, multiple note values are separated with ","
3943 and multiple notes are separated with "\r\n".
3944 When logging named notes with %{name}note, the
3945 explicitly configured separator is used between note
3946 values. When logging all notes with %note, the
3947 explicitly configured separator is used between
3948 individual notes. There is currently no way to
3949 specify both value and notes separators when logging
3950 all notes with %note.
3952 Connection related format codes:
3954 >a Client source IP address
3956 >p Client source port
3957 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3958 >la Local IP address the client connected to
3959 >lp Local port number the client connected to
3960 >qos Client connection TOS/DSCP value set by Squid
3961 >nfmark Client connection netfilter mark set by Squid
3963 la Local listening IP address the client connection was connected to.
3964 lp Local listening port number the client connection was connected to.
3966 <a Server IP address of the last server or peer connection
3967 <A Server FQDN or peer name
3968 <p Server port number of the last server or peer connection
3969 <la Local IP address of the last server or peer connection
3970 <lp Local port number of the last server or peer connection
3971 <qos Server connection TOS/DSCP value set by Squid
3972 <nfmark Server connection netfilter mark set by Squid
3974 Time related format codes:
3976 ts Seconds since epoch
3977 tu subsecond time (milliseconds)
3978 tl Local time. Optional strftime format argument
3979 default %d/%b/%Y:%H:%M:%S %z
3980 tg GMT time. Optional strftime format argument
3981 default %d/%b/%Y:%H:%M:%S %z
3982 tr Response time (milliseconds)
3983 dt Total time spent making DNS lookups (milliseconds)
3984 tS Approximate master transaction start time in
3985 <full seconds since epoch>.<fractional seconds> format.
3986 Currently, Squid considers the master transaction
3987 started when a complete HTTP request header initiating
3988 the transaction is received from the client. This is
3989 the same value that Squid uses to calculate transaction
3990 response time when logging %tr to access.log. Currently,
3991 Squid uses millisecond resolution for %tS values,
3992 similar to the default access.log "current time" field
3995 Access Control related format codes:
3997 et Tag returned by external acl
3998 ea Log string returned by external acl
3999 un User name (any available)
4000 ul User name from authentication
4001 ue User name from external acl helper
4002 ui User name from ident
4003 us User name from SSL
4004 credentials Client credentials. The exact meaning depends on
4005 the authentication scheme: For Basic authentication,
4006 it is the password; for Digest, the realm sent by the
4007 client; for NTLM and Negotiate, the client challenge
4008 or client credentials prefixed with "YR " or "KK ".
4010 HTTP related format codes:
4014 [http::]rm Request method (GET/POST etc)
4015 [http::]>rm Request method from client
4016 [http::]<rm Request method sent to server or peer
4017 [http::]ru Request URL from client (historic, filtered for logging)
4018 [http::]>ru Request URL from client
4019 [http::]<ru Request URL sent to server or peer
4020 [http::]>rs Request URL scheme from client
4021 [http::]<rs Request URL scheme sent to server or peer
4022 [http::]>rd Request URL domain from client
4023 [http::]<rd Request URL domain sent to server or peer
4024 [http::]>rP Request URL port from client
4025 [http::]<rP Request URL port sent to server or peer
4026 [http::]rp Request URL path excluding hostname
4027 [http::]>rp Request URL path excluding hostname from client
4028 [http::]<rp Request URL path excluding hostname sent to server or peer
4029 [http::]rv Request protocol version
4030 [http::]>rv Request protocol version from client
4031 [http::]<rv Request protocol version sent to server or peer
4033 [http::]>h Original received request header.
4034 Usually differs from the request header sent by
4035 Squid, although most fields are often preserved.
4036 Accepts optional header field name/value filter
4037 argument using name[:[separator]element] format.
4038 [http::]>ha Received request header after adaptation and
4039 redirection (pre-cache REQMOD vectoring point).
4040 Usually differs from the request header sent by
4041 Squid, although most fields are often preserved.
4042 Optional header name argument as for >h
4047 [http::]<Hs HTTP status code received from the next hop
4048 [http::]>Hs HTTP status code sent to the client
4050 [http::]<h Reply header. Optional header name argument
4053 [http::]mt MIME content type
4058 [http::]st Total size of request + reply traffic with client
4059 [http::]>st Total size of request received from client.
4060 Excluding chunked encoding bytes.
4061 [http::]<st Total size of reply sent to client (after adaptation)
4063 [http::]>sh Size of request headers received from client
4064 [http::]<sh Size of reply headers sent to client (after adaptation)
4066 [http::]<sH Reply high offset sent
4067 [http::]<sS Upstream object size
4069 [http::]<bs Number of HTTP-equivalent message body bytes
4070 received from the next hop, excluding chunked
4071 transfer encoding and control messages.
4072 Generated FTP/Gopher listings are treated as
4078 [http::]<pt Peer response time in milliseconds. The timer starts
4079 when the last request byte is sent to the next hop
4080 and stops when the last response byte is received.
4081 [http::]<tt Total time in milliseconds. The timer
4082 starts with the first connect request (or write I/O)
4083 sent to the first selected peer. The timer stops
4084 with the last I/O with the last peer.
4086 Squid handling related format codes:
4088 Ss Squid request status (TCP_MISS etc)
4089 Sh Squid hierarchy status (DEFAULT_PARENT etc)
4091 SSL-related format codes:
4093 ssl::bump_mode SslBump decision for the transaction:
4095 For CONNECT requests that initiated bumping of
4096 a connection and for any request received on
4097 an already bumped connection, Squid logs the
4098 corresponding SslBump mode ("server-first" or
4099 "client-first"). See the ssl_bump option for
4100 more information about these modes.
4102 A "none" token is logged for requests that
4103 triggered "ssl_bump" ACL evaluation matching
4104 either a "none" rule or no rules at all.
4106 In all other cases, a single dash ("-") is
4109 ssl::>sni SSL client SNI sent to Squid. Available only
4110 after the peek, stare, or splice SSL bumping
4113 If ICAP is enabled, the following code becomes available (as
4114 well as ICAP log codes documented with the icap_log option):
4116 icap::tt Total ICAP processing time for the HTTP
4117 transaction. The timer ticks when ICAP
4118 ACLs are checked and when ICAP
4119 transaction is in progress.
4121 If adaptation is enabled the following three codes become available:
4123 adapt::<last_h The header of the last ICAP response or
4124 meta-information from the last eCAP
4125 transaction related to the HTTP transaction.
4126 Like <h, accepts an optional header name
4129 adapt::sum_trs Summed adaptation transaction response
4130 times recorded as a comma-separated list in
4131 the order of transaction start time. Each time
4132 value is recorded as an integer number,
4133 representing response time of one or more
4134 adaptation (ICAP or eCAP) transaction in
4135 milliseconds. When a failed transaction is
4136 being retried or repeated, its time is not
4137 logged individually but added to the
4138 replacement (next) transaction. See also:
4141 adapt::all_trs All adaptation transaction response times.
4142 Same as adaptation_strs but response times of
4143 individual transactions are never added
4144 together. Instead, all transaction response
4145 times are recorded individually.
4147 You can prefix adapt::*_trs format codes with adaptation
4148 service name in curly braces to record response time(s) specific
4149 to that service. For example: %{my_service}adapt::sum_trs
4151 If SSL is enabled, the following formating codes become available:
4153 %ssl::>cert_subject The Subject field of the received client
4154 SSL certificate or a dash ('-') if Squid has
4155 received an invalid/malformed certificate or
4156 no certificate at all. Consider encoding the
4157 logged value because Subject often has spaces.
4159 %ssl::>cert_issuer The Issuer field of the received client
4160 SSL certificate or a dash ('-') if Squid has
4161 received an invalid/malformed certificate or
4162 no certificate at all. Consider encoding the
4163 logged value because Issuer often has spaces.
4165 The default formats available (which do not need re-defining) are:
4167 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
4168 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
4169 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
4170 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
4171 logformat useragent %>a [%tl] "%{User-Agent}>h"
4173 NOTE: When the log_mime_hdrs directive is set to ON.
4174 The squid, common and combined formats have a safely encoded copy
4175 of the mime headers appended to each line within a pair of brackets.
4177 NOTE: The common and combined formats are not quite true to the Apache definition.
4178 The logs from Squid contain an extra status and hierarchy code appended.
4182 NAME: access_log cache_access_log
4184 LOC: Config.Log.accesslogs
4185 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
4187 Configures whether and how Squid logs HTTP and ICP transactions.
4188 If access logging is enabled, a single line is logged for every
4189 matching HTTP or ICP request. The recommended directive formats are:
4191 access_log <module>:<place> [option ...] [acl acl ...]
4192 access_log none [acl acl ...]
4194 The following directive format is accepted but may be deprecated:
4195 access_log <module>:<place> [<logformat name> [acl acl ...]]
4197 In most cases, the first ACL name must not contain the '=' character
4198 and should not be equal to an existing logformat name. You can always
4199 start with an 'all' ACL to work around those restrictions.
4201 Will log to the specified module:place using the specified format (which
4202 must be defined in a logformat directive) those entries which match
4203 ALL the acl's specified (which must be defined in acl clauses).
4204 If no acl is specified, all requests will be logged to this destination.
4206 ===== Available options for the recommended directive format =====
4208 logformat=name Names log line format (either built-in or
4209 defined by a logformat directive). Defaults
4212 buffer-size=64KB Defines approximate buffering limit for log
4213 records (see buffered_logs). Squid should not
4214 keep more than the specified size and, hence,
4215 should flush records before the buffer becomes
4216 full to avoid overflows under normal
4217 conditions (the exact flushing algorithm is
4218 module-dependent though). The on-error option
4219 controls overflow handling.
4221 on-error=die|drop Defines action on unrecoverable errors. The
4222 'drop' action ignores (i.e., does not log)
4223 affected log records. The default 'die' action
4224 kills the affected worker. The drop action
4225 support has not been tested for modules other
4228 ===== Modules Currently available =====
4230 none Do not log any requests matching these ACL.
4231 Do not specify Place or logformat name.
4233 stdio Write each log line to disk immediately at the completion of
4235 Place: the filename and path to be written.
4237 daemon Very similar to stdio. But instead of writing to disk the log
4238 line is passed to a daemon helper for asychronous handling instead.
4239 Place: varies depending on the daemon.
4241 log_file_daemon Place: the file name and path to be written.
4243 syslog To log each request via syslog facility.
4244 Place: The syslog facility and priority level for these entries.
4245 Place Format: facility.priority
4247 where facility could be any of:
4248 authpriv, daemon, local0 ... local7 or user.
4250 And priority could be any of:
4251 err, warning, notice, info, debug.
4253 udp To send each log line as text data to a UDP receiver.
4254 Place: The destination host name or IP and port.
4255 Place Format: //host:port
4257 tcp To send each log line as text data to a TCP receiver.
4258 Lines may be accumulated before sending (see buffered_logs).
4259 Place: The destination host name or IP and port.
4260 Place Format: //host:port
4263 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4269 LOC: Config.Log.icaplogs
4272 ICAP log files record ICAP transaction summaries, one line per
4275 The icap_log option format is:
4276 icap_log <filepath> [<logformat name> [acl acl ...]]
4277 icap_log none [acl acl ...]]
4279 Please see access_log option documentation for details. The two
4280 kinds of logs share the overall configuration approach and many
4283 ICAP processing of a single HTTP message or transaction may
4284 require multiple ICAP transactions. In such cases, multiple
4285 ICAP transaction log lines will correspond to a single access
4288 ICAP log uses logformat codes that make sense for an ICAP
4289 transaction. Header-related codes are applied to the HTTP header
4290 embedded in an ICAP server response, with the following caveats:
4291 For REQMOD, there is no HTTP response header unless the ICAP
4292 server performed request satisfaction. For RESPMOD, the HTTP
4293 request header is the header sent to the ICAP server. For
4294 OPTIONS, there are no HTTP headers.
4296 The following format codes are also available for ICAP logs:
4298 icap::<A ICAP server IP address. Similar to <A.
4300 icap::<service_name ICAP service name from the icap_service
4301 option in Squid configuration file.
4303 icap::ru ICAP Request-URI. Similar to ru.
4305 icap::rm ICAP request method (REQMOD, RESPMOD, or
4306 OPTIONS). Similar to existing rm.
4308 icap::>st Bytes sent to the ICAP server (TCP payload
4309 only; i.e., what Squid writes to the socket).
4311 icap::<st Bytes received from the ICAP server (TCP
4312 payload only; i.e., what Squid reads from
4315 icap::<bs Number of message body bytes received from the
4316 ICAP server. ICAP message body, if any, usually
4317 includes encapsulated HTTP message headers and
4318 possibly encapsulated HTTP message body. The
4319 HTTP body part is dechunked before its size is
4322 icap::tr Transaction response time (in
4323 milliseconds). The timer starts when
4324 the ICAP transaction is created and
4325 stops when the transaction is completed.
4328 icap::tio Transaction I/O time (in milliseconds). The
4329 timer starts when the first ICAP request
4330 byte is scheduled for sending. The timers
4331 stops when the last byte of the ICAP response
4334 icap::to Transaction outcome: ICAP_ERR* for all
4335 transaction errors, ICAP_OPT for OPTION
4336 transactions, ICAP_ECHO for 204
4337 responses, ICAP_MOD for message
4338 modification, and ICAP_SAT for request
4339 satisfaction. Similar to Ss.
4341 icap::Hs ICAP response status code. Similar to Hs.
4343 icap::>h ICAP request header(s). Similar to >h.
4345 icap::<h ICAP response header(s). Similar to <h.
4347 The default ICAP log format, which can be used without an explicit
4348 definition, is called icap_squid:
4350 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
4352 See also: logformat, log_icap, and %adapt::<last_h
4355 NAME: logfile_daemon
4357 DEFAULT: @DEFAULT_LOGFILED@
4358 LOC: Log::TheConfig.logfile_daemon
4360 Specify the path to the logfile-writing daemon. This daemon is
4361 used to write the access and store logs, if configured.
4363 Squid sends a number of commands to the log daemon:
4364 L<data>\n - logfile data
4369 r<n>\n - set rotate count to <n>
4370 b<n>\n - 1 = buffer output, 0 = don't buffer output
4372 No responses is expected.
4375 NAME: stats_collection
4377 LOC: Config.accessList.stats_collection
4379 DEFAULT_DOC: Allow logging for all transactions.
4380 COMMENT: allow|deny acl acl...
4382 This options allows you to control which requests gets accounted
4383 in performance counters.
4385 This clause only supports fast acl types.
4386 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4389 NAME: cache_store_log
4392 LOC: Config.Log.store
4394 Logs the activities of the storage manager. Shows which
4395 objects are ejected from the cache, and which objects are
4396 saved and for how long.
4397 There are not really utilities to analyze this data, so you can safely
4398 disable it (the default).
4400 Store log uses modular logging outputs. See access_log for the list
4401 of modules supported.
4404 cache_store_log stdio:@DEFAULT_STORE_LOG@
4405 cache_store_log daemon:@DEFAULT_STORE_LOG@
4408 NAME: cache_swap_state cache_swap_log
4410 LOC: Config.Log.swap
4412 DEFAULT_DOC: Store the journal inside its cache_dir
4414 Location for the cache "swap.state" file. This index file holds
4415 the metadata of objects saved on disk. It is used to rebuild
4416 the cache during startup. Normally this file resides in each
4417 'cache_dir' directory, but you may specify an alternate
4418 pathname here. Note you must give a full filename, not just
4419 a directory. Since this is the index for the whole object
4420 list you CANNOT periodically rotate it!
4422 If %s can be used in the file name it will be replaced with a
4423 a representation of the cache_dir name where each / is replaced
4424 with '.'. This is needed to allow adding/removing cache_dir
4425 lines when cache_swap_log is being used.
4427 If have more than one 'cache_dir', and %s is not used in the name
4428 these swap logs will have names such as:
4434 The numbered extension (which is added automatically)
4435 corresponds to the order of the 'cache_dir' lines in this
4436 configuration file. If you change the order of the 'cache_dir'
4437 lines in this file, these index files will NOT correspond to
4438 the correct 'cache_dir' entry (unless you manually rename
4439 them). We recommend you do NOT use this option. It is
4440 better to keep these index files in each 'cache_dir' directory.
4443 NAME: logfile_rotate
4446 LOC: Config.Log.rotateNumber
4448 Specifies the number of logfile rotations to make when you
4449 type 'squid -k rotate'. The default is 10, which will rotate
4450 with extensions 0 through 9. Setting logfile_rotate to 0 will
4451 disable the file name rotation, but the logfiles are still closed
4452 and re-opened. This will enable you to rename the logfiles
4453 yourself just before sending the rotate signal.
4455 Note, the 'squid -k rotate' command normally sends a USR1
4456 signal to the running squid process. In certain situations
4457 (e.g. on Linux with Async I/O), USR1 is used for other
4458 purposes, so -k rotate uses another signal. It is best to get
4459 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4462 Note, from Squid-3.1 this option is only a default for cache.log,
4463 that log can be rotated separately by using debug_options.
4468 DEFAULT: @DEFAULT_MIME_TABLE@
4469 LOC: Config.mimeTablePathname
4471 Path to Squid's icon configuration file.
4473 You shouldn't need to change this, but the default file contains
4474 examples and formatting information if you do.
4480 LOC: Config.onoff.log_mime_hdrs
4483 The Cache can record both the request and the response MIME
4484 headers for each HTTP transaction. The headers are encoded
4485 safely and will appear as two bracketed fields at the end of
4486 the access log (for either the native or httpd-emulated log
4487 formats). To enable this logging set log_mime_hdrs to 'on'.
4492 DEFAULT: @DEFAULT_PID_FILE@
4493 LOC: Config.pidFilename
4495 A filename to write the process-id to. To disable, enter "none".
4498 NAME: client_netmask
4500 LOC: Config.Addrs.client_netmask
4502 DEFAULT_DOC: Log full client IP address
4504 A netmask for client addresses in logfiles and cachemgr output.
4505 Change this to protect the privacy of your cache clients.
4506 A netmask of 255.255.255.0 will log all IP's in that range with
4507 the last digit set to '0'.
4510 NAME: strip_query_terms
4512 LOC: Config.onoff.strip_query_terms
4515 By default, Squid strips query terms from requested URLs before
4516 logging. This protects your user's privacy and reduces log size.
4518 When investigating HIT/MISS or other caching behaviour you
4519 will need to disable this to see the full URL used by Squid.
4526 LOC: Config.onoff.buffered_logs
4528 Whether to write/send access_log records ASAP or accumulate them and
4529 then write/send them in larger chunks. Buffering may improve
4530 performance because it decreases the number of I/Os. However,
4531 buffering increases the delay before log records become available to
4532 the final recipient (e.g., a disk file or logging daemon) and,
4533 hence, increases the risk of log records loss.
4535 Note that even when buffered_logs are off, Squid may have to buffer
4536 records if it cannot write/send them immediately due to pending I/Os
4537 (e.g., the I/O writing the previous log record) or connectivity loss.
4539 Currently honored by 'daemon' and 'tcp' access_log modules only.
4542 NAME: netdb_filename
4544 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4545 LOC: Config.netdbFilename
4548 Where Squid stores it's netdb journal.
4549 When enabled this journal preserves netdb state between restarts.
4551 To disable, enter "none".
4555 OPTIONS FOR TROUBLESHOOTING
4556 -----------------------------------------------------------------------------
4561 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4562 LOC: Debug::cache_log
4564 Squid administrative logging file.
4566 This is where general information about Squid behavior goes. You can
4567 increase the amount of data logged to this file and how often it is
4568 rotated with "debug_options"
4574 DEFAULT_DOC: Log all critical and important messages.
4575 LOC: Debug::debugOptions
4577 Logging options are set as section,level where each source file
4578 is assigned a unique section. Lower levels result in less
4579 output, Full debugging (level 9) can result in a very large
4580 log file, so be careful.
4582 The magic word "ALL" sets debugging levels for all sections.
4583 The default is to run with "ALL,1" to record important warnings.
4585 The rotate=N option can be used to keep more or less of these logs
4586 than would otherwise be kept by logfile_rotate.
4587 For most uses a single log should be enough to monitor current
4588 events affecting Squid.
4593 LOC: Config.coredump_dir
4594 DEFAULT_IF_NONE: none
4595 DEFAULT_DOC: Use the directory from where Squid was started.
4597 By default Squid leaves core files in the directory from where
4598 it was started. If you set 'coredump_dir' to a directory
4599 that exists, Squid will chdir() to that directory at startup
4600 and coredump files will be left there.
4604 # Leave coredumps in the first cache dir
4605 coredump_dir @DEFAULT_SWAP_DIR@
4611 OPTIONS FOR FTP GATEWAYING
4612 -----------------------------------------------------------------------------
4618 LOC: Config.Ftp.anon_user
4620 If you want the anonymous login password to be more informative
4621 (and enable the use of picky FTP servers), set this to something
4622 reasonable for your domain, like wwwuser@somewhere.net
4624 The reason why this is domainless by default is the
4625 request can be made on the behalf of a user in any domain,
4626 depending on how the cache is used.
4627 Some FTP server also validate the email address is valid
4628 (for example perl.com).
4634 LOC: Config.Ftp.passive
4636 If your firewall does not allow Squid to use passive
4637 connections, turn off this option.
4639 Use of ftp_epsv_all option requires this to be ON.
4645 LOC: Config.Ftp.epsv_all
4647 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4649 NATs may be able to put the connection on a "fast path" through the
4650 translator, as the EPRT command will never be used and therefore,
4651 translation of the data portion of the segments will never be needed.
4653 When a client only expects to do two-way FTP transfers this may be
4655 If squid finds that it must do a three-way FTP transfer after issuing
4656 an EPSV ALL command, the FTP session will fail.
4658 If you have any doubts about this option do not use it.
4659 Squid will nicely attempt all other connection methods.
4661 Requires ftp_passive to be ON (default) for any effect.
4667 LOC: Config.accessList.ftp_epsv
4669 FTP Protocol extensions permit the use of a special "EPSV" command.
4671 NATs may be able to put the connection on a "fast path" through the
4672 translator using EPSV, as the EPRT command will never be used
4673 and therefore, translation of the data portion of the segments
4674 will never be needed.
4676 EPSV is often required to interoperate with FTP servers on IPv6
4677 networks. On the other hand, it may break some IPv4 servers.
4679 By default, EPSV may try EPSV with any FTP server. To fine tune
4680 that decision, you may restrict EPSV to certain clients or servers
4683 ftp_epsv allow|deny al1 acl2 ...
4685 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
4687 Only fast ACLs are supported.
4688 Requires ftp_passive to be ON (default) for any effect.
4694 LOC: Config.Ftp.eprt
4696 FTP Protocol extensions permit the use of a special "EPRT" command.
4698 This extension provides a protocol neutral alternative to the
4699 IPv4-only PORT command. When supported it enables active FTP data
4700 channels over IPv6 and efficient NAT handling.
4702 Turning this OFF will prevent EPRT being attempted and will skip
4703 straight to using PORT for IPv4 servers.
4705 Some devices are known to not handle this extension correctly and
4706 may result in crashes. Devices which suport EPRT enough to fail
4707 cleanly will result in Squid attempting PORT anyway. This directive
4708 should only be disabled when EPRT results in device failures.
4710 WARNING: Doing so will convert Squid back to the old behavior with all
4711 the related problems with external NAT devices/layers and IPv4-only FTP.
4714 NAME: ftp_sanitycheck
4717 LOC: Config.Ftp.sanitycheck
4719 For security and data integrity reasons Squid by default performs
4720 sanity checks of the addresses of FTP data connections ensure the
4721 data connection is to the requested server. If you need to allow
4722 FTP connections to servers using another IP address for the data
4723 connection turn this off.
4726 NAME: ftp_telnet_protocol
4729 LOC: Config.Ftp.telnet
4731 The FTP protocol is officially defined to use the telnet protocol
4732 as transport channel for the control connection. However, many
4733 implementations are broken and does not respect this aspect of
4736 If you have trouble accessing files with ASCII code 255 in the
4737 path or similar problems involving this ASCII code you can
4738 try setting this directive to off. If that helps, report to the
4739 operator of the FTP server in question that their FTP server
4740 is broken and does not follow the FTP standard.
4744 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4745 -----------------------------------------------------------------------------
4750 DEFAULT: @DEFAULT_DISKD@
4751 LOC: Config.Program.diskd
4753 Specify the location of the diskd executable.
4754 Note this is only useful if you have compiled in
4755 diskd as one of the store io modules.
4758 NAME: unlinkd_program
4761 DEFAULT: @DEFAULT_UNLINKD@
4762 LOC: Config.Program.unlinkd
4764 Specify the location of the executable for file deletion process.
4767 NAME: pinger_program
4769 DEFAULT: @DEFAULT_PINGER@
4770 LOC: Config.pinger.program
4773 Specify the location of the executable for the pinger process.
4779 LOC: Config.pinger.enable
4782 Control whether the pinger is active at run-time.
4783 Enables turning ICMP pinger on and off with a simple
4784 squid -k reconfigure.
4789 OPTIONS FOR URL REWRITING
4790 -----------------------------------------------------------------------------
4793 NAME: url_rewrite_program redirect_program
4795 LOC: Config.Program.redirect
4798 Specify the location of the executable URL rewriter to use.
4799 Since they can perform almost any function there isn't one included.
4801 For each requested URL, the rewriter will receive on line with the format
4803 [channel-ID <SP>] URL [<SP> extras]<NL>
4805 See url_rewrite_extras on how to send "extras" with optional values to
4807 After processing the request the helper must reply using the following format:
4809 [channel-ID <SP>] result [<SP> kv-pairs]
4811 The result code can be:
4813 OK status=30N url="..."
4814 Redirect the URL to the one supplied in 'url='.
4815 'status=' is optional and contains the status code to send
4816 the client in Squids HTTP response. It must be one of the
4817 HTTP redirect status codes: 301, 302, 303, 307, 308.
4818 When no status is given Squid will use 302.
4820 OK rewrite-url="..."
4821 Rewrite the URL to the one supplied in 'rewrite-url='.
4822 The new URL is fetched directly by Squid and returned to
4823 the client as the response to its request.
4826 When neither of url= and rewrite-url= are sent Squid does
4830 Do not change the URL.
4833 An internal error occurred in the helper, preventing
4834 a result being identified. The 'message=' key name is
4835 reserved for delivering a log message.
4838 In addition to the above kv-pairs Squid also understands the following
4839 optional kv-pairs received from URL rewriters:
4841 Associates a TAG with the client TCP connection.
4842 The TAG is treated as a regular annotation but persists across
4843 future requests on the client connection rather than just the
4844 current request. A helper may update the TAG during subsequent
4845 requests be returning a new kv-pair.
4847 When using the concurrency= option the protocol is changed by
4848 introducing a query channel tag in front of the request/response.
4849 The query channel tag is a number between 0 and concurrency-1.
4850 This value must be echoed back unchanged to Squid as the first part
4851 of the response relating to its request.
4853 WARNING: URL re-writing ability should be avoided whenever possible.
4854 Use the URL redirect form of response instead.
4856 Re-write creates a difference in the state held by the client
4857 and server. Possibly causing confusion when the server response
4858 contains snippets of its view state. Embeded URLs, response
4859 and content Location headers, etc. are not re-written by this
4862 By default, a URL rewriter is not used.
4865 NAME: url_rewrite_children redirect_children
4866 TYPE: HelperChildConfig
4867 DEFAULT: 20 startup=0 idle=1 concurrency=0
4868 LOC: Config.redirectChildren
4870 The maximum number of redirector processes to spawn. If you limit
4871 it too few Squid will have to wait for them to process a backlog of
4872 URLs, slowing it down. If you allow too many they will use RAM
4873 and other system resources noticably.
4875 The startup= and idle= options allow some measure of skew in your
4880 Sets a minimum of how many processes are to be spawned when Squid
4881 starts or reconfigures. When set to zero the first request will
4882 cause spawning of the first child process to handle it.
4884 Starting too few will cause an initial slowdown in traffic as Squid
4885 attempts to simultaneously spawn enough processes to cope.
4889 Sets a minimum of how many processes Squid is to try and keep available
4890 at all times. When traffic begins to rise above what the existing
4891 processes can handle this many more will be spawned up to the maximum
4892 configured. A minimum setting of 1 is required.
4896 The number of requests each redirector helper can handle in
4897 parallel. Defaults to 0 which indicates the redirector
4898 is a old-style single threaded redirector.
4900 When this directive is set to a value >= 1 then the protocol
4901 used to communicate with the helper is modified to include
4902 an ID in front of the request/response. The ID from the request
4903 must be echoed back with the response to that request.
4907 Sets the maximum number of queued requests.
4908 If the queued requests exceed queue size and redirector_bypass
4909 configuration option is set, then redirector is bypassed. Otherwise, if
4910 overloading persists squid may abort its operation.
4911 The default value is set to 2*numberofchildren.
4914 NAME: url_rewrite_host_header redirect_rewrites_host_header
4917 LOC: Config.onoff.redir_rewrites_host
4919 To preserve same-origin security policies in browsers and
4920 prevent Host: header forgery by redirectors Squid rewrites
4921 any Host: header in redirected requests.
4923 If you are running an accelerator this may not be a wanted
4924 effect of a redirector. This directive enables you disable
4925 Host: alteration in reverse-proxy traffic.
4927 WARNING: Entries are cached on the result of the URL rewriting
4928 process, so be careful if you have domain-virtual hosts.
4930 WARNING: Squid and other software verifies the URL and Host
4931 are matching, so be careful not to relay through other proxies
4932 or inspecting firewalls with this disabled.
4935 NAME: url_rewrite_access redirector_access
4938 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4939 LOC: Config.accessList.redirector
4941 If defined, this access list specifies which requests are
4942 sent to the redirector processes.
4944 This clause supports both fast and slow acl types.
4945 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4948 NAME: url_rewrite_bypass redirector_bypass
4950 LOC: Config.onoff.redirector_bypass
4953 When this is 'on', a request will not go through the
4954 redirector if all the helpers are busy. If this is 'off'
4955 and the redirector queue grows too large, Squid will exit
4956 with a FATAL error and ask you to increase the number of
4957 redirectors. You should only enable this if the redirectors
4958 are not critical to your caching system. If you use
4959 redirectors for access control, and you enable this option,
4960 users may have access to pages they should not
4961 be allowed to request.
4962 This options sets default queue-size option of the url_rewrite_children
4966 NAME: url_rewrite_extras
4967 TYPE: TokenOrQuotedString
4968 LOC: Config.redirector_extras
4969 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
4971 Specifies a string to be append to request line format for the
4972 rewriter helper. "Quoted" format values may contain spaces and
4973 logformat %macros. In theory, any logformat %macro can be used.
4974 In practice, a %macro expands as a dash (-) if the helper request is
4975 sent before the required macro information is available to Squid.
4978 NAME: url_rewrite_timeout
4979 TYPE: url_rewrite_timeout
4982 DEFAULT_DOC: Squid waits for the helper response forever
4984 Squid times active requests to redirector. The timeout value and Squid
4985 reaction to a timed out request are configurable using the following
4988 url_rewrite_timeout timeout time-units on_timeout=<action> [response=<quoted-response>]
4990 supported timeout actions:
4991 fail Squid return a ERR_GATEWAY_FAILURE error page
4993 bypass Do not re-write the URL
4995 retry Send the lookup to the helper again
4997 use_configured_response Use the <quoted-response> as
5002 OPTIONS FOR STORE ID
5003 -----------------------------------------------------------------------------
5006 NAME: store_id_program storeurl_rewrite_program
5008 LOC: Config.Program.store_id
5011 Specify the location of the executable StoreID helper to use.
5012 Since they can perform almost any function there isn't one included.
5014 For each requested URL, the helper will receive one line with the format
5016 [channel-ID <SP>] URL [<SP> extras]<NL>
5019 After processing the request the helper must reply using the following format:
5021 [channel-ID <SP>] result [<SP> kv-pairs]
5023 The result code can be:
5026 Use the StoreID supplied in 'store-id='.
5029 The default is to use HTTP request URL as the store ID.
5032 An internal error occured in the helper, preventing
5033 a result being identified.
5035 In addition to the above kv-pairs Squid also understands the following
5036 optional kv-pairs received from URL rewriters:
5038 Associates a TAG with the client TCP connection.
5039 Please see url_rewrite_program related documentation for this
5042 Helper programs should be prepared to receive and possibly ignore
5043 additional whitespace-separated tokens on each input line.
5045 When using the concurrency= option the protocol is changed by
5046 introducing a query channel tag in front of the request/response.
5047 The query channel tag is a number between 0 and concurrency-1.
5048 This value must be echoed back unchanged to Squid as the first part
5049 of the response relating to its request.
5051 NOTE: when using StoreID refresh_pattern will apply to the StoreID
5052 returned from the helper and not the URL.
5054 WARNING: Wrong StoreID value returned by a careless helper may result
5055 in the wrong cached response returned to the user.
5057 By default, a StoreID helper is not used.
5060 NAME: store_id_extras
5061 TYPE: TokenOrQuotedString
5062 LOC: Config.storeId_extras
5063 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5065 Specifies a string to be append to request line format for the
5066 StoreId helper. "Quoted" format values may contain spaces and
5067 logformat %macros. In theory, any logformat %macro can be used.
5068 In practice, a %macro expands as a dash (-) if the helper request is
5069 sent before the required macro information is available to Squid.
5072 NAME: store_id_children storeurl_rewrite_children
5073 TYPE: HelperChildConfig
5074 DEFAULT: 20 startup=0 idle=1 concurrency=0
5075 LOC: Config.storeIdChildren
5077 The maximum number of StoreID helper processes to spawn. If you limit
5078 it too few Squid will have to wait for them to process a backlog of
5079 requests, slowing it down. If you allow too many they will use RAM
5080 and other system resources noticably.
5082 The startup= and idle= options allow some measure of skew in your
5087 Sets a minimum of how many processes are to be spawned when Squid
5088 starts or reconfigures. When set to zero the first request will
5089 cause spawning of the first child process to handle it.
5091 Starting too few will cause an initial slowdown in traffic as Squid
5092 attempts to simultaneously spawn enough processes to cope.
5096 Sets a minimum of how many processes Squid is to try and keep available
5097 at all times. When traffic begins to rise above what the existing
5098 processes can handle this many more will be spawned up to the maximum
5099 configured. A minimum setting of 1 is required.
5103 The number of requests each storeID helper can handle in
5104 parallel. Defaults to 0 which indicates the helper
5105 is a old-style single threaded program.
5107 When this directive is set to a value >= 1 then the protocol
5108 used to communicate with the helper is modified to include
5109 an ID in front of the request/response. The ID from the request
5110 must be echoed back with the response to that request.
5114 Sets the maximum number of queued requests.
5115 If the queued requests exceed queue size and store_id_bypass
5116 configuration option is set, then storeID helper is bypassed. Otherwise,
5117 if overloading persists squid may abort its operation.
5118 The default value is set to 2*numberofchildren.
5121 NAME: store_id_access storeurl_rewrite_access
5124 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5125 LOC: Config.accessList.store_id
5127 If defined, this access list specifies which requests are
5128 sent to the StoreID processes. By default all requests
5131 This clause supports both fast and slow acl types.
5132 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5135 NAME: store_id_bypass storeurl_rewrite_bypass
5137 LOC: Config.onoff.store_id_bypass
5140 When this is 'on', a request will not go through the
5141 helper if all helpers are busy. If this is 'off'
5142 and the helper queue grows too large, Squid will exit
5143 with a FATAL error and ask you to increase the number of
5144 helpers. You should only enable this if the helperss
5145 are not critical to your caching system. If you use
5146 helpers for critical caching components, and you enable this
5147 option, users may not get objects from cache.
5148 This options sets default queue-size option of the store_id_children
5153 OPTIONS FOR TUNING THE CACHE
5154 -----------------------------------------------------------------------------
5157 NAME: cache no_cache
5160 DEFAULT_DOC: By default, this directive is unused and has no effect.
5161 LOC: Config.accessList.noCache
5163 Requests denied by this directive will not be served from the cache
5164 and their responses will not be stored in the cache. This directive
5165 has no effect on other transactions and on already cached responses.
5167 This clause supports both fast and slow acl types.
5168 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5170 This and the two other similar caching directives listed below are
5171 checked at different transaction processing stages, have different
5172 access to response information, affect different cache operations,
5173 and differ in slow ACLs support:
5175 * cache: Checked before Squid makes a hit/miss determination.
5176 No access to reply information!
5177 Denies both serving a hit and storing a miss.
5178 Supports both fast and slow ACLs.
5179 * send_hit: Checked after a hit was detected.
5180 Has access to reply (hit) information.
5181 Denies serving a hit only.
5182 Supports fast ACLs only.
5183 * store_miss: Checked before storing a cachable miss.
5184 Has access to reply (miss) information.
5185 Denies storing a miss only.
5186 Supports fast ACLs only.
5188 If you are not sure which of the three directives to use, apply the
5189 following decision logic:
5191 * If your ACL(s) are of slow type _and_ need response info, redesign.
5192 Squid does not support that particular combination at this time.
5194 * If your directive ACL(s) are of slow type, use "cache"; and/or
5195 * if your directive ACL(s) need no response info, use "cache".
5197 * If you do not want the response cached, use store_miss; and/or
5198 * if you do not want a hit on a cached response, use send_hit.
5204 DEFAULT_DOC: By default, this directive is unused and has no effect.
5205 LOC: Config.accessList.sendHit
5207 Responses denied by this directive will not be served from the cache
5208 (but may still be cached, see store_miss). This directive has no
5209 effect on the responses it allows and on the cached objects.
5211 Please see the "cache" directive for a summary of differences among
5212 store_miss, send_hit, and cache directives.
5214 Unlike the "cache" directive, send_hit only supports fast acl
5215 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5219 # apply custom Store ID mapping to some URLs
5220 acl MapMe dstdomain .c.example.com
5221 store_id_program ...
5222 store_id_access allow MapMe
5224 # but prevent caching of special responses
5225 # such as 302 redirects that cause StoreID loops
5226 acl Ordinary http_status 200-299
5227 store_miss deny MapMe !Ordinary
5229 # and do not serve any previously stored special responses
5230 # from the cache (in case they were already cached before
5231 # the above store_miss rule was in effect).
5232 send_hit deny MapMe !Ordinary
5238 DEFAULT_DOC: By default, this directive is unused and has no effect.
5239 LOC: Config.accessList.storeMiss
5241 Responses denied by this directive will not be cached (but may still
5242 be served from the cache, see send_hit). This directive has no
5243 effect on the responses it allows and on the already cached responses.
5245 Please see the "cache" directive for a summary of differences among
5246 store_miss, send_hit, and cache directives. See the
5247 send_hit directive for a usage example.
5249 Unlike the "cache" directive, store_miss only supports fast acl
5250 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5256 LOC: Config.maxStale
5259 This option puts an upper limit on how stale content Squid
5260 will serve from the cache if cache validation fails.
5261 Can be overriden by the refresh_pattern max-stale option.
5264 NAME: refresh_pattern
5265 TYPE: refreshpattern
5269 usage: refresh_pattern [-i] regex min percent max [options]
5271 By default, regular expressions are CASE-SENSITIVE. To make
5272 them case-insensitive, use the -i option.
5274 'Min' is the time (in minutes) an object without an explicit
5275 expiry time should be considered fresh. The recommended
5276 value is 0, any higher values may cause dynamic applications
5277 to be erroneously cached unless the application designer
5278 has taken the appropriate actions.
5280 'Percent' is a percentage of the objects age (time since last
5281 modification age) an object without explicit expiry time
5282 will be considered fresh.
5284 'Max' is an upper limit on how long objects without an explicit
5285 expiry time will be considered fresh.
5287 options: override-expire
5292 ignore-must-revalidate
5299 override-expire enforces min age even if the server
5300 sent an explicit expiry time (e.g., with the
5301 Expires: header or Cache-Control: max-age). Doing this
5302 VIOLATES the HTTP standard. Enabling this feature
5303 could make you liable for problems which it causes.
5305 Note: override-expire does not enforce staleness - it only extends
5306 freshness / min. If the server returns a Expires time which
5307 is longer than your max time, Squid will still consider
5308 the object fresh for that period of time.
5310 override-lastmod enforces min age even on objects
5311 that were modified recently.
5313 reload-into-ims changes a client no-cache or ``reload''
5314 request for a cached entry into a conditional request using
5315 If-Modified-Since and/or If-None-Match headers, provided the
5316 cached entry has a Last-Modified and/or a strong ETag header.
5317 Doing this VIOLATES the HTTP standard. Enabling this feature
5318 could make you liable for problems which it causes.
5320 ignore-reload ignores a client no-cache or ``reload''
5321 header. Doing this VIOLATES the HTTP standard. Enabling
5322 this feature could make you liable for problems which
5325 ignore-no-store ignores any ``Cache-control: no-store''
5326 headers received from a server. Doing this VIOLATES
5327 the HTTP standard. Enabling this feature could make you
5328 liable for problems which it causes.
5330 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
5331 headers received from a server. Doing this VIOLATES
5332 the HTTP standard. Enabling this feature could make you
5333 liable for problems which it causes.
5335 ignore-private ignores any ``Cache-control: private''
5336 headers received from a server. Doing this VIOLATES
5337 the HTTP standard. Enabling this feature could make you
5338 liable for problems which it causes.
5340 ignore-auth caches responses to requests with authorization,
5341 as if the originserver had sent ``Cache-control: public''
5342 in the response header. Doing this VIOLATES the HTTP standard.
5343 Enabling this feature could make you liable for problems which
5346 refresh-ims causes squid to contact the origin server
5347 when a client issues an If-Modified-Since request. This
5348 ensures that the client will receive an updated version
5349 if one is available.
5351 store-stale stores responses even if they don't have explicit
5352 freshness or a validator (i.e., Last-Modified or an ETag)
5353 present, or if they're already stale. By default, Squid will
5354 not cache such responses because they usually can't be
5355 reused. Note that such responses will be stale by default.
5357 max-stale=NN provide a maximum staleness factor. Squid won't
5358 serve objects more stale than this even if it failed to
5359 validate the object. Default: use the max_stale global limit.
5361 Basically a cached object is:
5363 FRESH if expires < now, else STALE
5365 FRESH if lm-factor < percent, else STALE
5369 The refresh_pattern lines are checked in the order listed here.
5370 The first entry which matches is used. If none of the entries
5371 match the default will be used.
5373 Note, you must uncomment all the default lines if you want
5374 to change one. The default setting is only active if none is
5380 # Add any of your own refresh_pattern entries above these.
5382 refresh_pattern ^ftp: 1440 20% 10080
5383 refresh_pattern ^gopher: 1440 0% 1440
5384 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5385 refresh_pattern . 0 20% 4320
5389 NAME: quick_abort_min
5393 LOC: Config.quickAbort.min
5396 NAME: quick_abort_max
5400 LOC: Config.quickAbort.max
5403 NAME: quick_abort_pct
5407 LOC: Config.quickAbort.pct
5409 The cache by default continues downloading aborted requests
5410 which are almost completed (less than 16 KB remaining). This
5411 may be undesirable on slow (e.g. SLIP) links and/or very busy
5412 caches. Impatient users may tie up file descriptors and
5413 bandwidth by repeatedly requesting and immediately aborting
5416 When the user aborts a request, Squid will check the
5417 quick_abort values to the amount of data transferred until
5420 If the transfer has less than 'quick_abort_min' KB remaining,
5421 it will finish the retrieval.
5423 If the transfer has more than 'quick_abort_max' KB remaining,
5424 it will abort the retrieval.
5426 If more than 'quick_abort_pct' of the transfer has completed,
5427 it will finish the retrieval.
5429 If you do not want any retrieval to continue after the client
5430 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5433 If you want retrievals to always continue if they are being
5434 cached set 'quick_abort_min' to '-1 KB'.
5437 NAME: read_ahead_gap
5438 COMMENT: buffer-size
5440 LOC: Config.readAheadGap
5443 The amount of data the cache will buffer ahead of what has been
5444 sent to the client when retrieving an object from another server.
5448 IFDEF: USE_HTTP_VIOLATIONS
5451 LOC: Config.negativeTtl
5454 Set the Default Time-to-Live (TTL) for failed requests.
5455 Certain types of failures (such as "connection refused" and
5456 "404 Not Found") are able to be negatively-cached for a short time.
5457 Modern web servers should provide Expires: header, however if they
5458 do not this can provide a minimum TTL.
5459 The default is not to cache errors with unknown expiry details.
5461 Note that this is different from negative caching of DNS lookups.
5463 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5464 this feature could make you liable for problems which it
5468 NAME: positive_dns_ttl
5471 LOC: Config.positiveDnsTtl
5474 Upper limit on how long Squid will cache positive DNS responses.
5475 Default is 6 hours (360 minutes). This directive must be set
5476 larger than negative_dns_ttl.
5479 NAME: negative_dns_ttl
5482 LOC: Config.negativeDnsTtl
5485 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5486 This also sets the lower cache limit on positive lookups.
5487 Minimum value is 1 second, and it is not recommendable to go
5488 much below 10 seconds.
5491 NAME: range_offset_limit
5492 COMMENT: size [acl acl...]
5494 LOC: Config.rangeOffsetLimit
5497 usage: (size) [units] [[!]aclname]
5499 Sets an upper limit on how far (number of bytes) into the file
5500 a Range request may be to cause Squid to prefetch the whole file.
5501 If beyond this limit, Squid forwards the Range request as it is and
5502 the result is NOT cached.
5504 This is to stop a far ahead range request (lets say start at 17MB)
5505 from making Squid fetch the whole object up to that point before
5506 sending anything to the client.
5508 Multiple range_offset_limit lines may be specified, and they will
5509 be searched from top to bottom on each request until a match is found.
5510 The first match found will be used. If no line matches a request, the
5511 default limit of 0 bytes will be used.
5513 'size' is the limit specified as a number of units.
5515 'units' specifies whether to use bytes, KB, MB, etc.
5516 If no units are specified bytes are assumed.
5518 A size of 0 causes Squid to never fetch more than the
5519 client requested. (default)
5521 A size of 'none' causes Squid to always fetch the object from the
5522 beginning so it may cache the result. (2.0 style)
5524 'aclname' is the name of a defined ACL.
5526 NP: Using 'none' as the byte value here will override any quick_abort settings
5527 that may otherwise apply to the range request. The range request will
5528 be fully fetched from start to finish regardless of the client
5529 actions. This affects bandwidth usage.
5532 NAME: minimum_expiry_time
5535 LOC: Config.minimum_expiry_time
5538 The minimum caching time according to (Expires - Date)
5539 headers Squid honors if the object can't be revalidated.
5540 The default is 60 seconds.
5542 In reverse proxy environments it might be desirable to honor
5543 shorter object lifetimes. It is most likely better to make
5544 your server return a meaningful Last-Modified header however.
5546 In ESI environments where page fragments often have short
5547 lifetimes, this will often be best set to 0.
5550 NAME: store_avg_object_size
5554 LOC: Config.Store.avgObjectSize
5556 Average object size, used to estimate number of objects your
5557 cache can hold. The default is 13 KB.
5559 This is used to pre-seed the cache index memory allocation to
5560 reduce expensive reallocate operations while handling clients
5561 traffic. Too-large values may result in memory allocation during
5562 peak traffic, too-small values will result in wasted memory.
5564 Check the cache manager 'info' report metrics for the real
5565 object sizes seen by your Squid before tuning this.
5568 NAME: store_objects_per_bucket
5571 LOC: Config.Store.objectsPerBucket
5573 Target number of objects per bucket in the store hash table.
5574 Lowering this value increases the total number of buckets and
5575 also the storage maintenance rate. The default is 20.
5580 -----------------------------------------------------------------------------
5583 NAME: request_header_max_size
5587 LOC: Config.maxRequestHeaderSize
5589 This specifies the maximum size for HTTP headers in a request.
5590 Request headers are usually relatively small (about 512 bytes).
5591 Placing a limit on the request header size will catch certain
5592 bugs (for example with persistent connections) and possibly
5593 buffer-overflow or denial-of-service attacks.
5596 NAME: reply_header_max_size
5600 LOC: Config.maxReplyHeaderSize
5602 This specifies the maximum size for HTTP headers in a reply.
5603 Reply headers are usually relatively small (about 512 bytes).
5604 Placing a limit on the reply header size will catch certain
5605 bugs (for example with persistent connections) and possibly
5606 buffer-overflow or denial-of-service attacks.
5609 NAME: request_body_max_size
5613 DEFAULT_DOC: No limit.
5614 LOC: Config.maxRequestBodySize
5616 This specifies the maximum size for an HTTP request body.
5617 In other words, the maximum size of a PUT/POST request.
5618 A user who attempts to send a request with a body larger
5619 than this limit receives an "Invalid Request" error message.
5620 If you set this parameter to a zero (the default), there will
5621 be no limit imposed.
5623 See also client_request_buffer_max_size for an alternative
5624 limitation on client uploads which can be configured.
5627 NAME: client_request_buffer_max_size
5631 LOC: Config.maxRequestBufferSize
5633 This specifies the maximum buffer size of a client request.
5634 It prevents squid eating too much memory when somebody uploads
5638 NAME: chunked_request_body_max_size
5642 LOC: Config.maxChunkedRequestBodySize
5644 A broken or confused HTTP/1.1 client may send a chunked HTTP
5645 request to Squid. Squid does not have full support for that
5646 feature yet. To cope with such requests, Squid buffers the
5647 entire request and then dechunks request body to create a
5648 plain HTTP/1.0 request with a known content length. The plain
5649 request is then used by the rest of Squid code as usual.
5651 The option value specifies the maximum size of the buffer used
5652 to hold the request before the conversion. If the chunked
5653 request size exceeds the specified limit, the conversion
5654 fails, and the client receives an "unsupported request" error,
5655 as if dechunking was disabled.
5657 Dechunking is enabled by default. To disable conversion of
5658 chunked requests, set the maximum to zero.
5660 Request dechunking feature and this option in particular are a
5661 temporary hack. When chunking requests and responses are fully
5662 supported, there will be no need to buffer a chunked request.
5666 IFDEF: USE_HTTP_VIOLATIONS
5669 DEFAULT_DOC: Obey RFC 2616.
5670 LOC: Config.accessList.brokenPosts
5672 A list of ACL elements which, if matched, causes Squid to send
5673 an extra CRLF pair after the body of a PUT/POST request.
5675 Some HTTP servers has broken implementations of PUT/POST,
5676 and rely on an extra CRLF pair sent by some WWW clients.
5678 Quote from RFC2616 section 4.1 on this matter:
5680 Note: certain buggy HTTP/1.0 client implementations generate an
5681 extra CRLF's after a POST request. To restate what is explicitly
5682 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5683 a request with an extra CRLF.
5685 This clause only supports fast acl types.
5686 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5689 acl buggy_server url_regex ^http://....
5690 broken_posts allow buggy_server
5693 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5696 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5698 LOC: Adaptation::Config::use_indirect_client
5700 Controls whether the indirect client IP address (instead of the direct
5701 client IP address) is passed to adaptation services.
5703 See also: follow_x_forwarded_for adaptation_send_client_ip
5707 IFDEF: USE_HTTP_VIOLATIONS
5711 LOC: Config.onoff.via
5713 If set (default), Squid will include a Via header in requests and
5714 replies as required by RFC2616.
5720 LOC: Config.onoff.ie_refresh
5723 Microsoft Internet Explorer up until version 5.5 Service
5724 Pack 1 has an issue with transparent proxies, wherein it
5725 is impossible to force a refresh. Turning this on provides
5726 a partial fix to the problem, by causing all IMS-REFRESH
5727 requests from older IE versions to check the origin server
5728 for fresh content. This reduces hit ratio by some amount
5729 (~10% in my experience), but allows users to actually get
5730 fresh content when they want it. Note because Squid
5731 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5732 of 5.5 is unchanged from old versions of Squid (i.e. a
5733 forced refresh is impossible). Newer versions of IE will,
5734 hopefully, continue to have the new behavior and will be
5735 handled based on that assumption. This option defaults to
5736 the old Squid behavior, which is better for hit ratios but
5737 worse for clients using IE, if they need to be able to
5738 force fresh content.
5741 NAME: vary_ignore_expire
5744 LOC: Config.onoff.vary_ignore_expire
5747 Many HTTP servers supporting Vary gives such objects
5748 immediate expiry time with no cache-control header
5749 when requested by a HTTP/1.0 client. This option
5750 enables Squid to ignore such expiry times until
5751 HTTP/1.1 is fully implemented.
5753 WARNING: If turned on this may eventually cause some
5754 varying objects not intended for caching to get cached.
5757 NAME: request_entities
5759 LOC: Config.onoff.request_entities
5762 Squid defaults to deny GET and HEAD requests with request entities,
5763 as the meaning of such requests are undefined in the HTTP standard
5764 even if not explicitly forbidden.
5766 Set this directive to on if you have clients which insists
5767 on sending request entities in GET or HEAD requests. But be warned
5768 that there is server software (both proxies and web servers) which
5769 can fail to properly process this kind of request which may make you
5770 vulnerable to cache pollution attacks if enabled.
5773 NAME: request_header_access
5774 IFDEF: USE_HTTP_VIOLATIONS
5775 TYPE: http_header_access
5776 LOC: Config.request_header_access
5778 DEFAULT_DOC: No limits.
5780 Usage: request_header_access header_name allow|deny [!]aclname ...
5782 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5783 this feature could make you liable for problems which it
5786 This option replaces the old 'anonymize_headers' and the
5787 older 'http_anonymizer' option with something that is much
5788 more configurable. A list of ACLs for each header name allows
5789 removal of specific header fields under specific conditions.
5791 This option only applies to outgoing HTTP request headers (i.e.,
5792 headers sent by Squid to the next HTTP hop such as a cache peer
5793 or an origin server). The option has no effect during cache hit
5794 detection. The equivalent adaptation vectoring point in ICAP
5795 terminology is post-cache REQMOD.
5797 The option is applied to individual outgoing request header
5798 fields. For each request header field F, Squid uses the first
5799 qualifying sets of request_header_access rules:
5801 1. Rules with header_name equal to F's name.
5802 2. Rules with header_name 'Other', provided F's name is not
5803 on the hard-coded list of commonly used HTTP header names.
5804 3. Rules with header_name 'All'.
5806 Within that qualifying rule set, rule ACLs are checked as usual.
5807 If ACLs of an "allow" rule match, the header field is allowed to
5808 go through as is. If ACLs of a "deny" rule match, the header is
5809 removed and request_header_replace is then checked to identify
5810 if the removed header has a replacement. If no rules within the
5811 set have matching ACLs, the header field is left as is.
5813 For example, to achieve the same behavior as the old
5814 'http_anonymizer standard' option, you should use:
5816 request_header_access From deny all
5817 request_header_access Referer deny all
5818 request_header_access User-Agent deny all
5820 Or, to reproduce the old 'http_anonymizer paranoid' feature
5823 request_header_access Authorization allow all
5824 request_header_access Proxy-Authorization allow all
5825 request_header_access Cache-Control allow all
5826 request_header_access Content-Length allow all
5827 request_header_access Content-Type allow all
5828 request_header_access Date allow all
5829 request_header_access Host allow all
5830 request_header_access If-Modified-Since allow all
5831 request_header_access Pragma allow all
5832 request_header_access Accept allow all
5833 request_header_access Accept-Charset allow all
5834 request_header_access Accept-Encoding allow all
5835 request_header_access Accept-Language allow all
5836 request_header_access Connection allow all
5837 request_header_access All deny all
5839 HTTP reply headers are controlled with the reply_header_access directive.
5841 By default, all headers are allowed (no anonymizing is performed).
5844 NAME: reply_header_access
5845 IFDEF: USE_HTTP_VIOLATIONS
5846 TYPE: http_header_access
5847 LOC: Config.reply_header_access
5849 DEFAULT_DOC: No limits.
5851 Usage: reply_header_access header_name allow|deny [!]aclname ...
5853 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5854 this feature could make you liable for problems which it
5857 This option only applies to reply headers, i.e., from the
5858 server to the client.
5860 This is the same as request_header_access, but in the other
5861 direction. Please see request_header_access for detailed
5864 For example, to achieve the same behavior as the old
5865 'http_anonymizer standard' option, you should use:
5867 reply_header_access Server deny all
5868 reply_header_access WWW-Authenticate deny all
5869 reply_header_access Link deny all
5871 Or, to reproduce the old 'http_anonymizer paranoid' feature
5874 reply_header_access Allow allow all
5875 reply_header_access WWW-Authenticate allow all
5876 reply_header_access Proxy-Authenticate allow all
5877 reply_header_access Cache-Control allow all
5878 reply_header_access Content-Encoding allow all
5879 reply_header_access Content-Length allow all
5880 reply_header_access Content-Type allow all
5881 reply_header_access Date allow all
5882 reply_header_access Expires allow all
5883 reply_header_access Last-Modified allow all
5884 reply_header_access Location allow all
5885 reply_header_access Pragma allow all
5886 reply_header_access Content-Language allow all
5887 reply_header_access Retry-After allow all
5888 reply_header_access Title allow all
5889 reply_header_access Content-Disposition allow all
5890 reply_header_access Connection allow all
5891 reply_header_access All deny all
5893 HTTP request headers are controlled with the request_header_access directive.
5895 By default, all headers are allowed (no anonymizing is
5899 NAME: request_header_replace header_replace
5900 IFDEF: USE_HTTP_VIOLATIONS
5901 TYPE: http_header_replace
5902 LOC: Config.request_header_access
5905 Usage: request_header_replace header_name message
5906 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
5908 This option allows you to change the contents of headers
5909 denied with request_header_access above, by replacing them
5910 with some fixed string.
5912 This only applies to request headers, not reply headers.
5914 By default, headers are removed if denied.
5917 NAME: reply_header_replace
5918 IFDEF: USE_HTTP_VIOLATIONS
5919 TYPE: http_header_replace
5920 LOC: Config.reply_header_access
5923 Usage: reply_header_replace header_name message
5924 Example: reply_header_replace Server Foo/1.0
5926 This option allows you to change the contents of headers
5927 denied with reply_header_access above, by replacing them
5928 with some fixed string.
5930 This only applies to reply headers, not request headers.
5932 By default, headers are removed if denied.
5935 NAME: request_header_add
5936 TYPE: HeaderWithAclList
5937 LOC: Config.request_header_add
5940 Usage: request_header_add field-name field-value acl1 [acl2] ...
5941 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
5943 This option adds header fields to outgoing HTTP requests (i.e.,
5944 request headers sent by Squid to the next HTTP hop such as a
5945 cache peer or an origin server). The option has no effect during
5946 cache hit detection. The equivalent adaptation vectoring point
5947 in ICAP terminology is post-cache REQMOD.
5949 Field-name is a token specifying an HTTP header name. If a
5950 standard HTTP header name is used, Squid does not check whether
5951 the new header conflicts with any existing headers or violates
5952 HTTP rules. If the request to be modified already contains a
5953 field with the same name, the old field is preserved but the
5954 header field values are not merged.
5956 Field-value is either a token or a quoted string. If quoted
5957 string format is used, then the surrounding quotes are removed
5958 while escape sequences and %macros are processed.
5960 In theory, all of the logformat codes can be used as %macros.
5961 However, unlike logging (which happens at the very end of
5962 transaction lifetime), the transaction may not yet have enough
5963 information to expand a macro when the new header value is needed.
5964 And some information may already be available to Squid but not yet
5965 committed where the macro expansion code can access it (report
5966 such instances!). The macro will be expanded into a single dash
5967 ('-') in such cases. Not all macros have been tested.
5969 One or more Squid ACLs may be specified to restrict header
5970 injection to matching requests. As always in squid.conf, all
5971 ACLs in an option ACL list must be satisfied for the insertion
5972 to happen. The request_header_add option supports fast ACLs
5981 This option used to log custom information about the master
5982 transaction. For example, an admin may configure Squid to log
5983 which "user group" the transaction belongs to, where "user group"
5984 will be determined based on a set of ACLs and not [just]
5985 authentication information.
5986 Values of key/value pairs can be logged using %{key}note macros:
5988 note key value acl ...
5989 logformat myFormat ... %{key}note ...
5992 NAME: relaxed_header_parser
5993 COMMENT: on|off|warn
5995 LOC: Config.onoff.relaxed_header_parser
5998 In the default "on" setting Squid accepts certain forms
5999 of non-compliant HTTP messages where it is unambiguous
6000 what the sending application intended even if the message
6001 is not correctly formatted. The messages is then normalized
6002 to the correct form when forwarded by Squid.
6004 If set to "warn" then a warning will be emitted in cache.log
6005 each time such HTTP error is encountered.
6007 If set to "off" then such HTTP errors will cause the request
6008 or response to be rejected.
6011 NAME: collapsed_forwarding
6014 LOC: Config.onoff.collapsed_forwarding
6017 This option controls whether Squid is allowed to merge multiple
6018 potentially cachable requests for the same URI before Squid knows
6019 whether the response is going to be cachable.
6021 This feature is disabled by default: Enabling collapsed forwarding
6022 needlessly delays forwarding requests that look cachable (when they are
6023 collapsed) but then need to be forwarded individually anyway because
6024 they end up being for uncachable content. However, in some cases, such
6025 as accelleration of highly cachable content with periodic or groupped
6026 expiration times, the gains from collapsing [large volumes of
6027 simultenous refresh requests] outweigh losses from such delays.
6032 -----------------------------------------------------------------------------
6035 NAME: forward_timeout
6038 LOC: Config.Timeout.forward
6041 This parameter specifies how long Squid should at most attempt in
6042 finding a forwarding path for the request before giving up.
6045 NAME: connect_timeout
6048 LOC: Config.Timeout.connect
6051 This parameter specifies how long to wait for the TCP connect to
6052 the requested server or peer to complete before Squid should
6053 attempt to find another path where to forward the request.
6056 NAME: peer_connect_timeout
6059 LOC: Config.Timeout.peer_connect
6062 This parameter specifies how long to wait for a pending TCP
6063 connection to a peer cache. The default is 30 seconds. You
6064 may also set different timeout values for individual neighbors
6065 with the 'connect-timeout' option on a 'cache_peer' line.
6071 LOC: Config.Timeout.read
6074 Applied on peer server connections.
6076 After each successful read(), the timeout will be extended by this
6077 amount. If no data is read again after this amount of time,
6078 the request is aborted and logged with ERR_READ_TIMEOUT.
6080 The default is 15 minutes.
6086 LOC: Config.Timeout.write
6089 This timeout is tracked for all connections that have data
6090 available for writing and are waiting for the socket to become
6091 ready. After each successful write, the timeout is extended by
6092 the configured amount. If Squid has data to write but the
6093 connection is not ready for the configured duration, the
6094 transaction associated with the connection is terminated. The
6095 default is 15 minutes.
6098 NAME: request_timeout
6100 LOC: Config.Timeout.request
6103 How long to wait for complete HTTP request headers after initial
6104 connection establishment.
6107 NAME: client_idle_pconn_timeout persistent_request_timeout
6109 LOC: Config.Timeout.clientIdlePconn
6112 How long to wait for the next HTTP request on a persistent
6113 client connection after the previous request completes.
6116 NAME: ftp_client_idle_timeout
6118 LOC: Config.Timeout.ftpClientIdle
6121 How long to wait for an FTP request on a connection to Squid ftp_port.
6122 Many FTP clients do not deal with idle connection closures well,
6123 necessitating a longer default timeout than client_idle_pconn_timeout
6124 used for incoming HTTP requests.
6127 NAME: client_lifetime
6130 LOC: Config.Timeout.lifetime
6133 The maximum amount of time a client (browser) is allowed to
6134 remain connected to the cache process. This protects the Cache
6135 from having a lot of sockets (and hence file descriptors) tied up
6136 in a CLOSE_WAIT state from remote clients that go away without
6137 properly shutting down (either because of a network failure or
6138 because of a poor client implementation). The default is one
6141 NOTE: The default value is intended to be much larger than any
6142 client would ever need to be connected to your cache. You
6143 should probably change client_lifetime only as a last resort.
6144 If you seem to have many client connections tying up
6145 filedescriptors, we recommend first tuning the read_timeout,
6146 request_timeout, persistent_request_timeout and quick_abort values.
6149 NAME: pconn_lifetime
6152 LOC: Config.Timeout.pconnLifetime
6155 Desired maximum lifetime of a persistent connection.
6156 When set, Squid will close a now-idle persistent connection that
6157 exceeded configured lifetime instead of moving the connection into
6158 the idle connection pool (or equivalent). No effect on ongoing/active
6159 transactions. Connection lifetime is the time period from the
6160 connection acceptance or opening time until "now".
6162 This limit is useful in environments with long-lived connections
6163 where Squid configuration or environmental factors change during a
6164 single connection lifetime. If unrestricted, some connections may
6165 last for hours and even days, ignoring those changes that should
6166 have affected their behavior or their existence.
6168 Currently, a new lifetime value supplied via Squid reconfiguration
6169 has no effect on already idle connections unless they become busy.
6171 When set to '0' this limit is not used.
6174 NAME: half_closed_clients
6176 LOC: Config.onoff.half_closed_clients
6179 Some clients may shutdown the sending side of their TCP
6180 connections, while leaving their receiving sides open. Sometimes,
6181 Squid can not tell the difference between a half-closed and a
6182 fully-closed TCP connection.
6184 By default, Squid will immediately close client connections when
6185 read(2) returns "no more data to read."
6187 Change this option to 'on' and Squid will keep open connections
6188 until a read(2) or write(2) on the socket returns an error.
6189 This may show some benefits for reverse proxies. But if not
6190 it is recommended to leave OFF.
6193 NAME: server_idle_pconn_timeout pconn_timeout
6195 LOC: Config.Timeout.serverIdlePconn
6198 Timeout for idle persistent connections to servers and other
6205 LOC: Ident::TheConfig.timeout
6208 Maximum time to wait for IDENT lookups to complete.
6210 If this is too high, and you enabled IDENT lookups from untrusted
6211 users, you might be susceptible to denial-of-service by having
6212 many ident requests going at once.
6215 NAME: shutdown_lifetime
6218 LOC: Config.shutdownLifetime
6221 When SIGTERM or SIGHUP is received, the cache is put into
6222 "shutdown pending" mode until all active sockets are closed.
6223 This value is the lifetime to set for all open descriptors
6224 during shutdown mode. Any active clients after this many
6225 seconds will receive a 'timeout' message.
6229 ADMINISTRATIVE PARAMETERS
6230 -----------------------------------------------------------------------------
6236 LOC: Config.adminEmail
6238 Email-address of local cache manager who will receive
6239 mail if the cache dies. The default is "webmaster".
6245 LOC: Config.EmailFrom
6247 From: email-address for mail sent when the cache dies.
6248 The default is to use 'squid@unique_hostname'.
6250 See also: unique_hostname directive.
6256 LOC: Config.EmailProgram
6258 Email program used to send mail if the cache dies.
6259 The default is "mail". The specified program must comply
6260 with the standard Unix mail syntax:
6261 mail-program recipient < mailfile
6263 Optional command line options can be specified.
6266 NAME: cache_effective_user
6268 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
6269 LOC: Config.effectiveUser
6271 If you start Squid as root, it will change its effective/real
6272 UID/GID to the user specified below. The default is to change
6273 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
6274 see also; cache_effective_group
6277 NAME: cache_effective_group
6280 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
6281 LOC: Config.effectiveGroup
6283 Squid sets the GID to the effective user's default group ID
6284 (taken from the password file) and supplementary group list
6285 from the groups membership.
6287 If you want Squid to run with a specific GID regardless of
6288 the group memberships of the effective user then set this
6289 to the group (or GID) you want Squid to run as. When set
6290 all other group privileges of the effective user are ignored
6291 and only this GID is effective. If Squid is not started as
6292 root the user starting Squid MUST be member of the specified
6295 This option is not recommended by the Squid Team.
6296 Our preference is for administrators to configure a secure
6297 user account for squid with UID/GID matching system policies.
6300 NAME: httpd_suppress_version_string
6304 LOC: Config.onoff.httpd_suppress_version_string
6306 Suppress Squid version string info in HTTP headers and HTML error pages.
6309 NAME: visible_hostname
6311 LOC: Config.visibleHostname
6313 DEFAULT_DOC: Automatically detect the system host name
6315 If you want to present a special hostname in error messages, etc,
6316 define this. Otherwise, the return value of gethostname()
6317 will be used. If you have multiple caches in a cluster and
6318 get errors about IP-forwarding you must set them to have individual
6319 names with this setting.
6322 NAME: unique_hostname
6324 LOC: Config.uniqueHostname
6326 DEFAULT_DOC: Copy the value from visible_hostname
6328 If you want to have multiple machines with the same
6329 'visible_hostname' you must give each machine a different
6330 'unique_hostname' so forwarding loops can be detected.
6333 NAME: hostname_aliases
6335 LOC: Config.hostnameAliases
6338 A list of other DNS names your cache has.
6346 Minimum umask which should be enforced while the proxy
6347 is running, in addition to the umask set at startup.
6349 For a traditional octal representation of umasks, start
6354 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6355 -----------------------------------------------------------------------------
6357 This section contains parameters for the (optional) cache
6358 announcement service. This service is provided to help
6359 cache administrators locate one another in order to join or
6360 create cache hierarchies.
6362 An 'announcement' message is sent (via UDP) to the registration
6363 service by Squid. By default, the announcement message is NOT
6364 SENT unless you enable it with 'announce_period' below.
6366 The announcement message includes your hostname, plus the
6367 following information from this configuration file:
6373 All current information is processed regularly and made
6374 available on the Web at http://www.ircache.net/Cache/Tracker/.
6377 NAME: announce_period
6379 LOC: Config.Announce.period
6381 DEFAULT_DOC: Announcement messages disabled.
6383 This is how frequently to send cache announcements.
6385 To enable announcing your cache, just set an announce period.
6388 announce_period 1 day
6393 DEFAULT: tracker.ircache.net
6394 LOC: Config.Announce.host
6396 Set the hostname where announce registration messages will be sent.
6398 See also announce_port and announce_file
6404 LOC: Config.Announce.file
6406 The contents of this file will be included in the announce
6407 registration messages.
6413 LOC: Config.Announce.port
6415 Set the port where announce registration messages will be sent.
6417 See also announce_host and announce_file
6421 HTTPD-ACCELERATOR OPTIONS
6422 -----------------------------------------------------------------------------
6425 NAME: httpd_accel_surrogate_id
6428 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
6429 LOC: Config.Accel.surrogate_id
6431 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
6432 need an identification token to allow control targeting. Because
6433 a farm of surrogates may all perform the same tasks, they may share
6434 an identification token.
6437 NAME: http_accel_surrogate_remote
6441 LOC: Config.onoff.surrogate_is_remote
6443 Remote surrogates (such as those in a CDN) honour the header
6444 "Surrogate-Control: no-store-remote".
6446 Set this to on to have squid behave as a remote surrogate.
6450 IFDEF: USE_SQUID_ESI
6451 COMMENT: libxml2|expat|custom
6453 LOC: ESIParser::Type
6456 ESI markup is not strictly XML compatible. The custom ESI parser
6457 will give higher performance, but cannot handle non ASCII character
6462 DELAY POOL PARAMETERS
6463 -----------------------------------------------------------------------------
6467 TYPE: delay_pool_count
6469 IFDEF: USE_DELAY_POOLS
6472 This represents the number of delay pools to be used. For example,
6473 if you have one class 2 delay pool and one class 3 delays pool, you
6474 have a total of 2 delay pools.
6476 See also delay_parameters, delay_class, delay_access for pool
6477 configuration details.
6481 TYPE: delay_pool_class
6483 IFDEF: USE_DELAY_POOLS
6486 This defines the class of each delay pool. There must be exactly one
6487 delay_class line for each delay pool. For example, to define two
6488 delay pools, one of class 2 and one of class 3, the settings above
6492 delay_pools 4 # 4 delay pools
6493 delay_class 1 2 # pool 1 is a class 2 pool
6494 delay_class 2 3 # pool 2 is a class 3 pool
6495 delay_class 3 4 # pool 3 is a class 4 pool
6496 delay_class 4 5 # pool 4 is a class 5 pool
6498 The delay pool classes are:
6500 class 1 Everything is limited by a single aggregate
6503 class 2 Everything is limited by a single aggregate
6504 bucket as well as an "individual" bucket chosen
6505 from bits 25 through 32 of the IPv4 address.
6507 class 3 Everything is limited by a single aggregate
6508 bucket as well as a "network" bucket chosen
6509 from bits 17 through 24 of the IP address and a
6510 "individual" bucket chosen from bits 17 through
6511 32 of the IPv4 address.
6513 class 4 Everything in a class 3 delay pool, with an
6514 additional limit on a per user basis. This
6515 only takes effect if the username is established
6516 in advance - by forcing authentication in your
6519 class 5 Requests are grouped according their tag (see
6520 external_acl's tag= reply).
6523 Each pool also requires a delay_parameters directive to configure the pool size
6524 and speed limits used whenever the pool is applied to a request. Along with
6525 a set of delay_access directives to determine when it is used.
6527 NOTE: If an IP address is a.b.c.d
6528 -> bits 25 through 32 are "d"
6529 -> bits 17 through 24 are "c"
6530 -> bits 17 through 32 are "c * 256 + d"
6532 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6533 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6535 This clause only supports fast acl types.
6536 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6538 See also delay_parameters and delay_access.
6542 TYPE: delay_pool_access
6544 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6545 IFDEF: USE_DELAY_POOLS
6548 This is used to determine which delay pool a request falls into.
6550 delay_access is sorted per pool and the matching starts with pool 1,
6551 then pool 2, ..., and finally pool N. The first delay pool where the
6552 request is allowed is selected for the request. If it does not allow
6553 the request to any pool then the request is not delayed (default).
6555 For example, if you want some_big_clients in delay
6556 pool 1 and lotsa_little_clients in delay pool 2:
6558 delay_access 1 allow some_big_clients
6559 delay_access 1 deny all
6560 delay_access 2 allow lotsa_little_clients
6561 delay_access 2 deny all
6562 delay_access 3 allow authenticated_clients
6564 See also delay_parameters and delay_class.
6568 NAME: delay_parameters
6569 TYPE: delay_pool_rates
6571 IFDEF: USE_DELAY_POOLS
6574 This defines the parameters for a delay pool. Each delay pool has
6575 a number of "buckets" associated with it, as explained in the
6576 description of delay_class.
6578 For a class 1 delay pool, the syntax is:
6580 delay_parameters pool aggregate
6582 For a class 2 delay pool:
6584 delay_parameters pool aggregate individual
6586 For a class 3 delay pool:
6588 delay_parameters pool aggregate network individual
6590 For a class 4 delay pool:
6592 delay_parameters pool aggregate network individual user
6594 For a class 5 delay pool:
6596 delay_parameters pool tagrate
6598 The option variables are:
6600 pool a pool number - ie, a number between 1 and the
6601 number specified in delay_pools as used in
6604 aggregate the speed limit parameters for the aggregate bucket
6607 individual the speed limit parameters for the individual
6608 buckets (class 2, 3).
6610 network the speed limit parameters for the network buckets
6613 user the speed limit parameters for the user buckets
6616 tagrate the speed limit parameters for the tag buckets
6619 A pair of delay parameters is written restore/maximum, where restore is
6620 the number of bytes (not bits - modem and network speeds are usually
6621 quoted in bits) per second placed into the bucket, and maximum is the
6622 maximum number of bytes which can be in the bucket at any time.
6624 There must be one delay_parameters line for each delay pool.
6627 For example, if delay pool number 1 is a class 2 delay pool as in the
6628 above example, and is being used to strictly limit each host to 64Kbit/sec
6629 (plus overheads), with no overall limit, the line is:
6631 delay_parameters 1 none 8000/8000
6633 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
6635 Note that the word 'none' is used to represent no limit.
6638 And, if delay pool number 2 is a class 3 delay pool as in the above
6639 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6640 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6641 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6642 to permit a decent web page to be downloaded at a decent speed
6643 (if the network is not being limited due to overuse) but slow down
6644 large downloads more significantly:
6646 delay_parameters 2 32000/32000 8000/8000 600/8000
6648 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
6649 8 x 8000 KByte/sec -> 64Kbit/sec.
6650 8 x 600 Byte/sec -> 4800bit/sec.
6653 Finally, for a class 4 delay pool as in the example - each user will
6654 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6656 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6659 See also delay_class and delay_access.
6663 NAME: delay_initial_bucket_level
6664 COMMENT: (percent, 0-100)
6667 IFDEF: USE_DELAY_POOLS
6668 LOC: Config.Delay.initial
6670 The initial bucket percentage is used to determine how much is put
6671 in each bucket when squid starts, is reconfigured, or first notices
6672 a host accessing it (in class 2 and class 3, individual hosts and
6673 networks only have buckets associated with them once they have been
6678 CLIENT DELAY POOL PARAMETERS
6679 -----------------------------------------------------------------------------
6682 NAME: client_delay_pools
6683 TYPE: client_delay_pool_count
6685 IFDEF: USE_DELAY_POOLS
6686 LOC: Config.ClientDelay
6688 This option specifies the number of client delay pools used. It must
6689 preceed other client_delay_* options.
6692 client_delay_pools 2
6694 See also client_delay_parameters and client_delay_access.
6697 NAME: client_delay_initial_bucket_level
6698 COMMENT: (percent, 0-no_limit)
6701 IFDEF: USE_DELAY_POOLS
6702 LOC: Config.ClientDelay.initial
6704 This option determines the initial bucket size as a percentage of
6705 max_bucket_size from client_delay_parameters. Buckets are created
6706 at the time of the "first" connection from the matching IP. Idle
6707 buckets are periodically deleted up.
6709 You can specify more than 100 percent but note that such "oversized"
6710 buckets are not refilled until their size goes down to max_bucket_size
6711 from client_delay_parameters.
6714 client_delay_initial_bucket_level 50
6717 NAME: client_delay_parameters
6718 TYPE: client_delay_pool_rates
6720 IFDEF: USE_DELAY_POOLS
6721 LOC: Config.ClientDelay
6724 This option configures client-side bandwidth limits using the
6727 client_delay_parameters pool speed_limit max_bucket_size
6729 pool is an integer ID used for client_delay_access matching.
6731 speed_limit is bytes added to the bucket per second.
6733 max_bucket_size is the maximum size of a bucket, enforced after any
6734 speed_limit additions.
6736 Please see the delay_parameters option for more information and
6740 client_delay_parameters 1 1024 2048
6741 client_delay_parameters 2 51200 16384
6743 See also client_delay_access.
6747 NAME: client_delay_access
6748 TYPE: client_delay_pool_access
6750 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6751 IFDEF: USE_DELAY_POOLS
6752 LOC: Config.ClientDelay
6754 This option determines the client-side delay pool for the
6757 client_delay_access pool_ID allow|deny acl_name
6759 All client_delay_access options are checked in their pool ID
6760 order, starting with pool 1. The first checked pool with allowed
6761 request is selected for the request. If no ACL matches or there
6762 are no client_delay_access options, the request bandwidth is not
6765 The ACL-selected pool is then used to find the
6766 client_delay_parameters for the request. Client-side pools are
6767 not used to aggregate clients. Clients are always aggregated
6768 based on their source IP addresses (one bucket per source IP).
6770 This clause only supports fast acl types.
6771 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6772 Additionally, only the client TCP connection details are available.
6773 ACLs testing HTTP properties will not work.
6775 Please see delay_access for more examples.
6778 client_delay_access 1 allow low_rate_network
6779 client_delay_access 2 allow vips_network
6782 See also client_delay_parameters and client_delay_pools.
6786 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6787 -----------------------------------------------------------------------------
6792 LOC: Config.Wccp.router
6794 DEFAULT_DOC: WCCP disabled.
6797 Use this option to define your WCCP ``home'' router for
6800 wccp_router supports a single WCCP(v1) router
6802 wccp2_router supports multiple WCCPv2 routers
6804 only one of the two may be used at the same time and defines
6805 which version of WCCP to use.
6809 TYPE: IpAddress_list
6810 LOC: Config.Wccp2.router
6812 DEFAULT_DOC: WCCPv2 disabled.
6815 Use this option to define your WCCP ``home'' router for
6818 wccp_router supports a single WCCP(v1) router
6820 wccp2_router supports multiple WCCPv2 routers
6822 only one of the two may be used at the same time and defines
6823 which version of WCCP to use.
6828 LOC: Config.Wccp.version
6832 This directive is only relevant if you need to set up WCCP(v1)
6833 to some very old and end-of-life Cisco routers. In all other
6834 setups it must be left unset or at the default setting.
6835 It defines an internal version in the WCCP(v1) protocol,
6836 with version 4 being the officially documented protocol.
6838 According to some users, Cisco IOS 11.2 and earlier only
6839 support WCCP version 3. If you're using that or an earlier
6840 version of IOS, you may need to change this value to 3, otherwise
6841 do not specify this parameter.
6844 NAME: wccp2_rebuild_wait
6846 LOC: Config.Wccp2.rebuildwait
6850 If this is enabled Squid will wait for the cache dir rebuild to finish
6851 before sending the first wccp2 HereIAm packet
6854 NAME: wccp2_forwarding_method
6856 LOC: Config.Wccp2.forwarding_method
6860 WCCP2 allows the setting of forwarding methods between the
6861 router/switch and the cache. Valid values are as follows:
6863 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6864 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6866 Currently (as of IOS 12.4) cisco routers only support GRE.
6867 Cisco switches only support the L2 redirect assignment method.
6870 NAME: wccp2_return_method
6872 LOC: Config.Wccp2.return_method
6876 WCCP2 allows the setting of return methods between the
6877 router/switch and the cache for packets that the cache
6878 decides not to handle. Valid values are as follows:
6880 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6881 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6883 Currently (as of IOS 12.4) cisco routers only support GRE.
6884 Cisco switches only support the L2 redirect assignment.
6886 If the "ip wccp redirect exclude in" command has been
6887 enabled on the cache interface, then it is still safe for
6888 the proxy server to use a l2 redirect method even if this
6889 option is set to GRE.
6892 NAME: wccp2_assignment_method
6894 LOC: Config.Wccp2.assignment_method
6898 WCCP2 allows the setting of methods to assign the WCCP hash
6899 Valid values are as follows:
6901 hash - Hash assignment
6902 mask - Mask assignment
6904 As a general rule, cisco routers support the hash assignment method
6905 and cisco switches support the mask assignment method.
6910 LOC: Config.Wccp2.info
6911 DEFAULT_IF_NONE: standard 0
6912 DEFAULT_DOC: Use the 'web-cache' standard service.
6915 WCCP2 allows for multiple traffic services. There are two
6916 types: "standard" and "dynamic". The standard type defines
6917 one service id - http (id 0). The dynamic service ids can be from
6918 51 to 255 inclusive. In order to use a dynamic service id
6919 one must define the type of traffic to be redirected; this is done
6920 using the wccp2_service_info option.
6922 The "standard" type does not require a wccp2_service_info option,
6923 just specifying the service id will suffice.
6925 MD5 service authentication can be enabled by adding
6926 "password=<password>" to the end of this service declaration.
6930 wccp2_service standard 0 # for the 'web-cache' standard service
6931 wccp2_service dynamic 80 # a dynamic service type which will be
6932 # fleshed out with subsequent options.
6933 wccp2_service standard 0 password=foo
6936 NAME: wccp2_service_info
6937 TYPE: wccp2_service_info
6938 LOC: Config.Wccp2.info
6942 Dynamic WCCPv2 services require further information to define the
6943 traffic you wish to have diverted.
6947 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
6948 priority=<priority> ports=<port>,<port>..
6950 The relevant WCCPv2 flags:
6951 + src_ip_hash, dst_ip_hash
6952 + source_port_hash, dst_port_hash
6953 + src_ip_alt_hash, dst_ip_alt_hash
6954 + src_port_alt_hash, dst_port_alt_hash
6957 The port list can be one to eight entries.
6961 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
6962 priority=240 ports=80
6964 Note: the service id must have been defined by a previous
6965 'wccp2_service dynamic <id>' entry.
6970 LOC: Config.Wccp2.weight
6974 Each cache server gets assigned a set of the destination
6975 hash proportional to their weight.
6980 LOC: Config.Wccp.address
6982 DEFAULT_DOC: Address selected by the operating system.
6985 Use this option if you require WCCPv2 to use a specific
6988 The default behavior is to not bind to any specific address.
6993 LOC: Config.Wccp2.address
6995 DEFAULT_DOC: Address selected by the operating system.
6998 Use this option if you require WCCP to use a specific
7001 The default behavior is to not bind to any specific address.
7005 PERSISTENT CONNECTION HANDLING
7006 -----------------------------------------------------------------------------
7008 Also see "pconn_timeout" in the TIMEOUTS section
7011 NAME: client_persistent_connections
7013 LOC: Config.onoff.client_pconns
7016 Persistent connection support for clients.
7017 Squid uses persistent connections (when allowed). You can use
7018 this option to disable persistent connections with clients.
7021 NAME: server_persistent_connections
7023 LOC: Config.onoff.server_pconns
7026 Persistent connection support for servers.
7027 Squid uses persistent connections (when allowed). You can use
7028 this option to disable persistent connections with servers.
7031 NAME: persistent_connection_after_error
7033 LOC: Config.onoff.error_pconns
7036 With this directive the use of persistent connections after
7037 HTTP errors can be disabled. Useful if you have clients
7038 who fail to handle errors on persistent connections proper.
7041 NAME: detect_broken_pconn
7043 LOC: Config.onoff.detect_broken_server_pconns
7046 Some servers have been found to incorrectly signal the use
7047 of HTTP/1.0 persistent connections even on replies not
7048 compatible, causing significant delays. This server problem
7049 has mostly been seen on redirects.
7051 By enabling this directive Squid attempts to detect such
7052 broken replies and automatically assume the reply is finished
7053 after 10 seconds timeout.
7057 CACHE DIGEST OPTIONS
7058 -----------------------------------------------------------------------------
7061 NAME: digest_generation
7062 IFDEF: USE_CACHE_DIGESTS
7064 LOC: Config.onoff.digest_generation
7067 This controls whether the server will generate a Cache Digest
7068 of its contents. By default, Cache Digest generation is
7069 enabled if Squid is compiled with --enable-cache-digests defined.
7072 NAME: digest_bits_per_entry
7073 IFDEF: USE_CACHE_DIGESTS
7075 LOC: Config.digest.bits_per_entry
7078 This is the number of bits of the server's Cache Digest which
7079 will be associated with the Digest entry for a given HTTP
7080 Method and URL (public key) combination. The default is 5.
7083 NAME: digest_rebuild_period
7084 IFDEF: USE_CACHE_DIGESTS
7087 LOC: Config.digest.rebuild_period
7090 This is the wait time between Cache Digest rebuilds.
7093 NAME: digest_rewrite_period
7095 IFDEF: USE_CACHE_DIGESTS
7097 LOC: Config.digest.rewrite_period
7100 This is the wait time between Cache Digest writes to
7104 NAME: digest_swapout_chunk_size
7107 IFDEF: USE_CACHE_DIGESTS
7108 LOC: Config.digest.swapout_chunk_size
7111 This is the number of bytes of the Cache Digest to write to
7112 disk at a time. It defaults to 4096 bytes (4KB), the Squid
7116 NAME: digest_rebuild_chunk_percentage
7117 COMMENT: (percent, 0-100)
7118 IFDEF: USE_CACHE_DIGESTS
7120 LOC: Config.digest.rebuild_chunk_percentage
7123 This is the percentage of the Cache Digest to be scanned at a
7124 time. By default it is set to 10% of the Cache Digest.
7129 -----------------------------------------------------------------------------
7134 LOC: Config.Port.snmp
7136 DEFAULT_DOC: SNMP disabled.
7139 The port number where Squid listens for SNMP requests. To enable
7140 SNMP support set this to a suitable port number. Port number
7141 3401 is often used for the Squid SNMP agent. By default it's
7142 set to "0" (disabled)
7150 LOC: Config.accessList.snmp
7152 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
7155 Allowing or denying access to the SNMP port.
7157 All access to the agent is denied by default.
7160 snmp_access allow|deny [!]aclname ...
7162 This clause only supports fast acl types.
7163 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7166 snmp_access allow snmppublic localhost
7167 snmp_access deny all
7170 NAME: snmp_incoming_address
7172 LOC: Config.Addrs.snmp_incoming
7174 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
7177 Just like 'udp_incoming_address', but for the SNMP port.
7179 snmp_incoming_address is used for the SNMP socket receiving
7180 messages from SNMP agents.
7182 The default snmp_incoming_address is to listen on all
7183 available network interfaces.
7186 NAME: snmp_outgoing_address
7188 LOC: Config.Addrs.snmp_outgoing
7190 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
7193 Just like 'udp_outgoing_address', but for the SNMP port.
7195 snmp_outgoing_address is used for SNMP packets returned to SNMP
7198 If snmp_outgoing_address is not set it will use the same socket
7199 as snmp_incoming_address. Only change this if you want to have
7200 SNMP replies sent using another address than where this Squid
7201 listens for SNMP queries.
7203 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
7204 the same value since they both use the same port.
7209 -----------------------------------------------------------------------------
7212 NAME: icp_port udp_port
7215 DEFAULT_DOC: ICP disabled.
7216 LOC: Config.Port.icp
7218 The port number where Squid sends and receives ICP queries to
7219 and from neighbor caches. The standard UDP port for ICP is 3130.
7222 icp_port @DEFAULT_ICP_PORT@
7229 DEFAULT_DOC: HTCP disabled.
7230 LOC: Config.Port.htcp
7232 The port number where Squid sends and receives HTCP queries to
7233 and from neighbor caches. To turn it on you want to set it to
7240 NAME: log_icp_queries
7244 LOC: Config.onoff.log_udp
7246 If set, ICP queries are logged to access.log. You may wish
7247 do disable this if your ICP load is VERY high to speed things
7248 up or to simplify log analysis.
7251 NAME: udp_incoming_address
7253 LOC:Config.Addrs.udp_incoming
7255 DEFAULT_DOC: Accept packets from all machine interfaces.
7257 udp_incoming_address is used for UDP packets received from other
7260 The default behavior is to not bind to any specific address.
7262 Only change this if you want to have all UDP queries received on
7263 a specific interface/address.
7265 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
7266 modules. Altering it will affect all of them in the same manner.
7268 see also; udp_outgoing_address
7270 NOTE, udp_incoming_address and udp_outgoing_address can not
7271 have the same value since they both use the same port.
7274 NAME: udp_outgoing_address
7276 LOC: Config.Addrs.udp_outgoing
7278 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
7280 udp_outgoing_address is used for UDP packets sent out to other
7283 The default behavior is to not bind to any specific address.
7285 Instead it will use the same socket as udp_incoming_address.
7286 Only change this if you want to have UDP queries sent using another
7287 address than where this Squid listens for UDP queries from other
7290 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7291 modules. Altering it will affect all of them in the same manner.
7293 see also; udp_incoming_address
7295 NOTE, udp_incoming_address and udp_outgoing_address can not
7296 have the same value since they both use the same port.
7303 LOC: Config.onoff.icp_hit_stale
7305 If you want to return ICP_HIT for stale cache objects, set this
7306 option to 'on'. If you have sibling relationships with caches
7307 in other administrative domains, this should be 'off'. If you only
7308 have sibling relationships with caches under your control,
7309 it is probably okay to set this to 'on'.
7310 If set to 'on', your siblings should use the option "allow-miss"
7311 on their cache_peer lines for connecting to you.
7314 NAME: minimum_direct_hops
7317 LOC: Config.minDirectHops
7319 If using the ICMP pinging stuff, do direct fetches for sites
7320 which are no more than this many hops away.
7323 NAME: minimum_direct_rtt
7327 LOC: Config.minDirectRtt
7329 If using the ICMP pinging stuff, do direct fetches for sites
7330 which are no more than this many rtt milliseconds away.
7336 LOC: Config.Netdb.low
7338 The low water mark for the ICMP measurement database.
7340 Note: high watermark controlled by netdb_high directive.
7342 These watermarks are counts, not percents. The defaults are
7343 (low) 900 and (high) 1000. When the high water mark is
7344 reached, database entries will be deleted until the low
7351 LOC: Config.Netdb.high
7353 The high water mark for the ICMP measurement database.
7355 Note: low watermark controlled by netdb_low directive.
7357 These watermarks are counts, not percents. The defaults are
7358 (low) 900 and (high) 1000. When the high water mark is
7359 reached, database entries will be deleted until the low
7363 NAME: netdb_ping_period
7365 LOC: Config.Netdb.period
7368 The minimum period for measuring a site. There will be at
7369 least this much delay between successive pings to the same
7370 network. The default is five minutes.
7377 LOC: Config.onoff.query_icmp
7379 If you want to ask your peers to include ICMP data in their ICP
7380 replies, enable this option.
7382 If your peer has configured Squid (during compilation) with
7383 '--enable-icmp' that peer will send ICMP pings to origin server
7384 sites of the URLs it receives. If you enable this option the
7385 ICP replies from that peer will include the ICMP data (if available).
7386 Then, when choosing a parent cache, Squid will choose the parent with
7387 the minimal RTT to the origin server. When this happens, the
7388 hierarchy field of the access.log will be
7389 "CLOSEST_PARENT_MISS". This option is off by default.
7392 NAME: test_reachability
7396 LOC: Config.onoff.test_reachability
7398 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
7399 instead of ICP_MISS if the target host is NOT in the ICMP
7400 database, or has a zero RTT.
7403 NAME: icp_query_timeout
7406 DEFAULT_DOC: Dynamic detection.
7408 LOC: Config.Timeout.icp_query
7410 Normally Squid will automatically determine an optimal ICP
7411 query timeout value based on the round-trip-time of recent ICP
7412 queries. If you want to override the value determined by
7413 Squid, set this 'icp_query_timeout' to a non-zero value. This
7414 value is specified in MILLISECONDS, so, to use a 2-second
7415 timeout (the old default), you would write:
7417 icp_query_timeout 2000
7420 NAME: maximum_icp_query_timeout
7424 LOC: Config.Timeout.icp_query_max
7426 Normally the ICP query timeout is determined dynamically. But
7427 sometimes it can lead to very large values (say 5 seconds).
7428 Use this option to put an upper limit on the dynamic timeout
7429 value. Do NOT use this option to always use a fixed (instead
7430 of a dynamic) timeout value. To set a fixed timeout see the
7431 'icp_query_timeout' directive.
7434 NAME: minimum_icp_query_timeout
7438 LOC: Config.Timeout.icp_query_min
7440 Normally the ICP query timeout is determined dynamically. But
7441 sometimes it can lead to very small timeouts, even lower than
7442 the normal latency variance on your link due to traffic.
7443 Use this option to put an lower limit on the dynamic timeout
7444 value. Do NOT use this option to always use a fixed (instead
7445 of a dynamic) timeout value. To set a fixed timeout see the
7446 'icp_query_timeout' directive.
7449 NAME: background_ping_rate
7453 LOC: Config.backgroundPingRate
7455 Controls how often the ICP pings are sent to siblings that
7456 have background-ping set.
7460 MULTICAST ICP OPTIONS
7461 -----------------------------------------------------------------------------
7466 LOC: Config.mcast_group_list
7469 This tag specifies a list of multicast groups which your server
7470 should join to receive multicasted ICP queries.
7472 NOTE! Be very careful what you put here! Be sure you
7473 understand the difference between an ICP _query_ and an ICP
7474 _reply_. This option is to be set only if you want to RECEIVE
7475 multicast queries. Do NOT set this option to SEND multicast
7476 ICP (use cache_peer for that). ICP replies are always sent via
7477 unicast, so this option does not affect whether or not you will
7478 receive replies from multicast group members.
7480 You must be very careful to NOT use a multicast address which
7481 is already in use by another group of caches.
7483 If you are unsure about multicast, please read the Multicast
7484 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7486 Usage: mcast_groups 239.128.16.128 224.0.1.20
7488 By default, Squid doesn't listen on any multicast groups.
7491 NAME: mcast_miss_addr
7492 IFDEF: MULTICAST_MISS_STREAM
7494 LOC: Config.mcast_miss.addr
7496 DEFAULT_DOC: disabled.
7498 If you enable this option, every "cache miss" URL will
7499 be sent out on the specified multicast address.
7501 Do not enable this option unless you are are absolutely
7502 certain you understand what you are doing.
7505 NAME: mcast_miss_ttl
7506 IFDEF: MULTICAST_MISS_STREAM
7508 LOC: Config.mcast_miss.ttl
7511 This is the time-to-live value for packets multicasted
7512 when multicasting off cache miss URLs is enabled. By
7513 default this is set to 'site scope', i.e. 16.
7516 NAME: mcast_miss_port
7517 IFDEF: MULTICAST_MISS_STREAM
7519 LOC: Config.mcast_miss.port
7522 This is the port number to be used in conjunction with
7526 NAME: mcast_miss_encode_key
7527 IFDEF: MULTICAST_MISS_STREAM
7529 LOC: Config.mcast_miss.encode_key
7530 DEFAULT: XXXXXXXXXXXXXXXX
7532 The URLs that are sent in the multicast miss stream are
7533 encrypted. This is the encryption key.
7536 NAME: mcast_icp_query_timeout
7540 LOC: Config.Timeout.mcast_icp_query
7542 For multicast peers, Squid regularly sends out ICP "probes" to
7543 count how many other peers are listening on the given multicast
7544 address. This value specifies how long Squid should wait to
7545 count all the replies. The default is 2000 msec, or 2
7550 INTERNAL ICON OPTIONS
7551 -----------------------------------------------------------------------------
7554 NAME: icon_directory
7556 LOC: Config.icons.directory
7557 DEFAULT: @DEFAULT_ICON_DIR@
7559 Where the icons are stored. These are normally kept in
7563 NAME: global_internal_static
7565 LOC: Config.onoff.global_internal_static
7568 This directive controls is Squid should intercept all requests for
7569 /squid-internal-static/ no matter which host the URL is requesting
7570 (default on setting), or if nothing special should be done for
7571 such URLs (off setting). The purpose of this directive is to make
7572 icons etc work better in complex cache hierarchies where it may
7573 not always be possible for all corners in the cache mesh to reach
7574 the server generating a directory listing.
7577 NAME: short_icon_urls
7579 LOC: Config.icons.use_short_names
7582 If this is enabled Squid will use short URLs for icons.
7583 If disabled it will revert to the old behavior of including
7584 it's own name and port in the URL.
7586 If you run a complex cache hierarchy with a mix of Squid and
7587 other proxies you may need to disable this directive.
7592 -----------------------------------------------------------------------------
7595 NAME: error_directory
7597 LOC: Config.errorDirectory
7599 DEFAULT_DOC: Send error pages in the clients preferred language
7601 If you wish to create your own versions of the default
7602 error files to customize them to suit your company copy
7603 the error/template files to another directory and point
7606 WARNING: This option will disable multi-language support
7607 on error pages if used.
7609 The squid developers are interested in making squid available in
7610 a wide variety of languages. If you are making translations for a
7611 language that Squid does not currently provide please consider
7612 contributing your translation back to the project.
7613 http://wiki.squid-cache.org/Translations
7615 The squid developers working on translations are happy to supply drop-in
7616 translated error files in exchange for any new language contributions.
7619 NAME: error_default_language
7620 IFDEF: USE_ERR_LOCALES
7622 LOC: Config.errorDefaultLanguage
7624 DEFAULT_DOC: Generate English language pages.
7626 Set the default language which squid will send error pages in
7627 if no existing translation matches the clients language
7630 If unset (default) generic English will be used.
7632 The squid developers are interested in making squid available in
7633 a wide variety of languages. If you are interested in making
7634 translations for any language see the squid wiki for details.
7635 http://wiki.squid-cache.org/Translations
7638 NAME: error_log_languages
7639 IFDEF: USE_ERR_LOCALES
7641 LOC: Config.errorLogMissingLanguages
7644 Log to cache.log what languages users are attempting to
7645 auto-negotiate for translations.
7647 Successful negotiations are not logged. Only failures
7648 have meaning to indicate that Squid may need an upgrade
7649 of its error page translations.
7652 NAME: err_page_stylesheet
7654 LOC: Config.errorStylesheet
7655 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7657 CSS Stylesheet to pattern the display of Squid default error pages.
7659 For information on CSS see http://www.w3.org/Style/CSS/
7664 LOC: Config.errHtmlText
7667 HTML text to include in error messages. Make this a "mailto"
7668 URL to your admin address, or maybe just a link to your
7669 organizations Web page.
7671 To include this in your error messages, you must rewrite
7672 the error template files (found in the "errors" directory).
7673 Wherever you want the 'err_html_text' line to appear,
7674 insert a %L tag in the error template file.
7677 NAME: email_err_data
7680 LOC: Config.onoff.emailErrData
7683 If enabled, information about the occurred error will be
7684 included in the mailto links of the ERR pages (if %W is set)
7685 so that the email body contains the data.
7686 Syntax is <A HREF="mailto:%w%W">%w</A>
7691 LOC: Config.denyInfoList
7694 Usage: deny_info err_page_name acl
7695 or deny_info http://... acl
7696 or deny_info TCP_RESET acl
7698 This can be used to return a ERR_ page for requests which
7699 do not pass the 'http_access' rules. Squid remembers the last
7700 acl it evaluated in http_access, and if a 'deny_info' line exists
7701 for that ACL Squid returns a corresponding error page.
7703 The acl is typically the last acl on the http_access deny line which
7704 denied access. The exceptions to this rule are:
7705 - When Squid needs to request authentication credentials. It's then
7706 the first authentication related acl encountered
7707 - When none of the http_access lines matches. It's then the last
7708 acl processed on the last http_access line.
7709 - When the decision to deny access was made by an adaptation service,
7710 the acl name is the corresponding eCAP or ICAP service_name.
7712 NP: If providing your own custom error pages with error_directory
7713 you may also specify them by your custom file name:
7714 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7716 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7717 may be specified by prefixing the file name with the code and a colon.
7718 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7720 Alternatively you can tell Squid to reset the TCP connection
7721 by specifying TCP_RESET.
7723 Or you can specify an error URL or URL pattern. The browsers will
7724 get redirected to the specified URL after formatting tags have
7725 been replaced. Redirect will be done with 302 or 307 according to
7726 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7727 the URL. e.g. 303:http://example.com/
7730 %a - username (if available. Password NOT included)
7733 %E - Error description
7735 %H - Request domain name
7736 %i - Client IP Address
7738 %o - Message result from external ACL helper
7739 %p - Request Port number
7740 %P - Request Protocol name
7741 %R - Request URL path
7742 %T - Timestamp in RFC 1123 format
7743 %U - Full canonical URL from client
7744 (HTTPS URLs terminate with *)
7745 %u - Full canonical URL from client
7746 %w - Admin email from squid.conf
7748 %% - Literal percent (%) code
7753 OPTIONS INFLUENCING REQUEST FORWARDING
7754 -----------------------------------------------------------------------------
7757 NAME: nonhierarchical_direct
7759 LOC: Config.onoff.nonhierarchical_direct
7762 By default, Squid will send any non-hierarchical requests
7763 (not cacheable request type) direct to origin servers.
7765 When this is set to "off", Squid will prefer to send these
7766 requests to parents.
7768 Note that in most configurations, by turning this off you will only
7769 add latency to these request without any improvement in global hit
7772 This option only sets a preference. If the parent is unavailable a
7773 direct connection to the origin server may still be attempted. To
7774 completely prevent direct connections use never_direct.
7779 LOC: Config.onoff.prefer_direct
7782 Normally Squid tries to use parents for most requests. If you for some
7783 reason like it to first try going direct and only use a parent if
7784 going direct fails set this to on.
7786 By combining nonhierarchical_direct off and prefer_direct on you
7787 can set up Squid to use a parent as a backup path if going direct
7790 Note: If you want Squid to use parents for all requests see
7791 the never_direct directive. prefer_direct only modifies how Squid
7792 acts on cacheable requests.
7795 NAME: cache_miss_revalidate
7799 LOC: Config.onoff.cache_miss_revalidate
7801 RFC 7232 defines a conditional request mechanism to prevent
7802 response objects being unnecessarily transferred over the network.
7803 If that mechanism is used by the client and a cache MISS occurs
7804 it can prevent new cache entries being created.
7806 This option determines whether Squid on cache MISS will pass the
7807 client revalidation request to the server or tries to fetch new
7808 content for caching. It can be useful while the cache is mostly
7809 empty to more quickly have the cache populated by generating
7810 non-conditional GETs.
7812 When set to 'on' (default), Squid will pass all client If-* headers
7813 to the server. This permits server responses without a cacheable
7814 payload to be delivered and on MISS no new cache entry is created.
7816 When set to 'off' and if the request is cacheable, Squid will
7817 remove the clients If-Modified-Since and If-None-Match headers from
7818 the request sent to the server. This requests a 200 status response
7819 from the server to create a new cache entry with.
7824 LOC: Config.accessList.AlwaysDirect
7826 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7828 Usage: always_direct allow|deny [!]aclname ...
7830 Here you can use ACL elements to specify requests which should
7831 ALWAYS be forwarded by Squid to the origin servers without using
7832 any peers. For example, to always directly forward requests for
7833 local servers ignoring any parents or siblings you may have use
7836 acl local-servers dstdomain my.domain.net
7837 always_direct allow local-servers
7839 To always forward FTP requests directly, use
7842 always_direct allow FTP
7844 NOTE: There is a similar, but opposite option named
7845 'never_direct'. You need to be aware that "always_direct deny
7846 foo" is NOT the same thing as "never_direct allow foo". You
7847 may need to use a deny rule to exclude a more-specific case of
7848 some other rule. Example:
7850 acl local-external dstdomain external.foo.net
7851 acl local-servers dstdomain .foo.net
7852 always_direct deny local-external
7853 always_direct allow local-servers
7855 NOTE: If your goal is to make the client forward the request
7856 directly to the origin server bypassing Squid then this needs
7857 to be done in the client configuration. Squid configuration
7858 can only tell Squid how Squid should fetch the object.
7860 NOTE: This directive is not related to caching. The replies
7861 is cached as usual even if you use always_direct. To not cache
7862 the replies see the 'cache' directive.
7864 This clause supports both fast and slow acl types.
7865 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7870 LOC: Config.accessList.NeverDirect
7872 DEFAULT_DOC: Allow DNS results to be used for this request.
7874 Usage: never_direct allow|deny [!]aclname ...
7876 never_direct is the opposite of always_direct. Please read
7877 the description for always_direct if you have not already.
7879 With 'never_direct' you can use ACL elements to specify
7880 requests which should NEVER be forwarded directly to origin
7881 servers. For example, to force the use of a proxy for all
7882 requests, except those in your local domain use something like:
7884 acl local-servers dstdomain .foo.net
7885 never_direct deny local-servers
7886 never_direct allow all
7888 or if Squid is inside a firewall and there are local intranet
7889 servers inside the firewall use something like:
7891 acl local-intranet dstdomain .foo.net
7892 acl local-external dstdomain external.foo.net
7893 always_direct deny local-external
7894 always_direct allow local-intranet
7895 never_direct allow all
7897 This clause supports both fast and slow acl types.
7898 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7902 ADVANCED NETWORKING OPTIONS
7903 -----------------------------------------------------------------------------
7906 NAME: incoming_udp_average incoming_icp_average
7909 LOC: Config.comm_incoming.udp.average
7911 Heavy voodoo here. I can't even believe you are reading this.
7912 Are you crazy? Don't even think about adjusting these unless
7913 you understand the algorithms in comm_select.c first!
7916 NAME: incoming_tcp_average incoming_http_average
7919 LOC: Config.comm_incoming.tcp.average
7921 Heavy voodoo here. I can't even believe you are reading this.
7922 Are you crazy? Don't even think about adjusting these unless
7923 you understand the algorithms in comm_select.c first!
7926 NAME: incoming_dns_average
7929 LOC: Config.comm_incoming.dns.average
7931 Heavy voodoo here. I can't even believe you are reading this.
7932 Are you crazy? Don't even think about adjusting these unless
7933 you understand the algorithms in comm_select.c first!
7936 NAME: min_udp_poll_cnt min_icp_poll_cnt
7939 LOC: Config.comm_incoming.udp.min_poll
7941 Heavy voodoo here. I can't even believe you are reading this.
7942 Are you crazy? Don't even think about adjusting these unless
7943 you understand the algorithms in comm_select.c first!
7946 NAME: min_dns_poll_cnt
7949 LOC: Config.comm_incoming.dns.min_poll
7951 Heavy voodoo here. I can't even believe you are reading this.
7952 Are you crazy? Don't even think about adjusting these unless
7953 you understand the algorithms in comm_select.c first!
7956 NAME: min_tcp_poll_cnt min_http_poll_cnt
7959 LOC: Config.comm_incoming.tcp.min_poll
7961 Heavy voodoo here. I can't even believe you are reading this.
7962 Are you crazy? Don't even think about adjusting these unless
7963 you understand the algorithms in comm_select.c first!
7969 LOC: Config.accept_filter
7973 The name of an accept(2) filter to install on Squid's
7974 listen socket(s). This feature is perhaps specific to
7975 FreeBSD and requires support in the kernel.
7977 The 'httpready' filter delays delivering new connections
7978 to Squid until a full HTTP request has been received.
7979 See the accf_http(9) man page for details.
7981 The 'dataready' filter delays delivering new connections
7982 to Squid until there is some data to process.
7983 See the accf_dataready(9) man page for details.
7987 The 'data' filter delays delivering of new connections
7988 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
7989 You may optionally specify a number of seconds to wait by
7990 'data=N' where N is the number of seconds. Defaults to 30
7991 if not specified. See the tcp(7) man page for details.
7994 accept_filter httpready
7999 NAME: client_ip_max_connections
8001 LOC: Config.client_ip_max_connections
8003 DEFAULT_DOC: No limit.
8005 Set an absolute limit on the number of connections a single
8006 client IP can use. Any more than this and Squid will begin to drop
8007 new connections from the client until it closes some links.
8009 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
8010 connections from the client. For finer control use the ACL access controls.
8012 Requires client_db to be enabled (the default).
8014 WARNING: This may noticably slow down traffic received via external proxies
8015 or NAT devices and cause them to rebound error messages back to their clients.
8018 NAME: tcp_recv_bufsize
8022 DEFAULT_DOC: Use operating system TCP defaults.
8023 LOC: Config.tcpRcvBufsz
8025 Size of receive buffer to set for TCP sockets. Probably just
8026 as easy to change your kernel's default.
8027 Omit from squid.conf to use the default buffer size.
8032 -----------------------------------------------------------------------------
8039 LOC: Adaptation::Icap::TheConfig.onoff
8042 If you want to enable the ICAP module support, set this to on.
8045 NAME: icap_connect_timeout
8048 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
8051 This parameter specifies how long to wait for the TCP connect to
8052 the requested ICAP server to complete before giving up and either
8053 terminating the HTTP transaction or bypassing the failure.
8055 The default for optional services is peer_connect_timeout.
8056 The default for essential services is connect_timeout.
8057 If this option is explicitly set, its value applies to all services.
8060 NAME: icap_io_timeout
8064 DEFAULT_DOC: Use read_timeout.
8065 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
8068 This parameter specifies how long to wait for an I/O activity on
8069 an established, active ICAP connection before giving up and
8070 either terminating the HTTP transaction or bypassing the
8074 NAME: icap_service_failure_limit
8075 COMMENT: limit [in memory-depth time-units]
8076 TYPE: icap_service_failure_limit
8078 LOC: Adaptation::Icap::TheConfig
8081 The limit specifies the number of failures that Squid tolerates
8082 when establishing a new TCP connection with an ICAP service. If
8083 the number of failures exceeds the limit, the ICAP service is
8084 not used for new ICAP requests until it is time to refresh its
8087 A negative value disables the limit. Without the limit, an ICAP
8088 service will not be considered down due to connectivity failures
8089 between ICAP OPTIONS requests.
8091 Squid forgets ICAP service failures older than the specified
8092 value of memory-depth. The memory fading algorithm
8093 is approximate because Squid does not remember individual
8094 errors but groups them instead, splitting the option
8095 value into ten time slots of equal length.
8097 When memory-depth is 0 and by default this option has no
8098 effect on service failure expiration.
8100 Squid always forgets failures when updating service settings
8101 using an ICAP OPTIONS transaction, regardless of this option
8105 # suspend service usage after 10 failures in 5 seconds:
8106 icap_service_failure_limit 10 in 5 seconds
8109 NAME: icap_service_revival_delay
8112 LOC: Adaptation::Icap::TheConfig.service_revival_delay
8115 The delay specifies the number of seconds to wait after an ICAP
8116 OPTIONS request failure before requesting the options again. The
8117 failed ICAP service is considered "down" until fresh OPTIONS are
8120 The actual delay cannot be smaller than the hardcoded minimum
8121 delay of 30 seconds.
8124 NAME: icap_preview_enable
8128 LOC: Adaptation::Icap::TheConfig.preview_enable
8131 The ICAP Preview feature allows the ICAP server to handle the
8132 HTTP message by looking only at the beginning of the message body
8133 or even without receiving the body at all. In some environments,
8134 previews greatly speedup ICAP processing.
8136 During an ICAP OPTIONS transaction, the server may tell Squid what
8137 HTTP messages should be previewed and how big the preview should be.
8138 Squid will not use Preview if the server did not request one.
8140 To disable ICAP Preview for all ICAP services, regardless of
8141 individual ICAP server OPTIONS responses, set this option to "off".
8143 icap_preview_enable off
8146 NAME: icap_preview_size
8149 LOC: Adaptation::Icap::TheConfig.preview_size
8151 DEFAULT_DOC: No preview sent.
8153 The default size of preview data to be sent to the ICAP server.
8154 This value might be overwritten on a per server basis by OPTIONS requests.
8157 NAME: icap_206_enable
8161 LOC: Adaptation::Icap::TheConfig.allow206_enable
8164 206 (Partial Content) responses is an ICAP extension that allows the
8165 ICAP agents to optionally combine adapted and original HTTP message
8166 content. The decision to combine is postponed until the end of the
8167 ICAP response. Squid supports Partial Content extension by default.
8169 Activation of the Partial Content extension is negotiated with each
8170 ICAP service during OPTIONS exchange. Most ICAP servers should handle
8171 negotation correctly even if they do not support the extension, but
8172 some might fail. To disable Partial Content support for all ICAP
8173 services and to avoid any negotiation, set this option to "off".
8179 NAME: icap_default_options_ttl
8182 LOC: Adaptation::Icap::TheConfig.default_options_ttl
8185 The default TTL value for ICAP OPTIONS responses that don't have
8186 an Options-TTL header.
8189 NAME: icap_persistent_connections
8193 LOC: Adaptation::Icap::TheConfig.reuse_connections
8196 Whether or not Squid should use persistent connections to
8200 NAME: adaptation_send_client_ip icap_send_client_ip
8202 IFDEF: USE_ADAPTATION
8204 LOC: Adaptation::Config::send_client_ip
8207 If enabled, Squid shares HTTP client IP information with adaptation
8208 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
8209 For eCAP, Squid sets the libecap::metaClientIp transaction option.
8211 See also: adaptation_uses_indirect_client
8214 NAME: adaptation_send_username icap_send_client_username
8216 IFDEF: USE_ADAPTATION
8218 LOC: Adaptation::Config::send_username
8221 This sends authenticated HTTP client username (if available) to
8222 the adaptation service.
8224 For ICAP, the username value is encoded based on the
8225 icap_client_username_encode option and is sent using the header
8226 specified by the icap_client_username_header option.
8229 NAME: icap_client_username_header
8232 LOC: Adaptation::Icap::TheConfig.client_username_header
8233 DEFAULT: X-Client-Username
8235 ICAP request header name to use for adaptation_send_username.
8238 NAME: icap_client_username_encode
8242 LOC: Adaptation::Icap::TheConfig.client_username_encode
8245 Whether to base64 encode the authenticated client username.
8249 TYPE: icap_service_type
8251 LOC: Adaptation::Icap::TheConfig
8254 Defines a single ICAP service using the following format:
8256 icap_service id vectoring_point uri [option ...]
8259 an opaque identifier or name which is used to direct traffic to
8260 this specific service. Must be unique among all adaptation
8261 services in squid.conf.
8263 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8264 This specifies at which point of transaction processing the
8265 ICAP service should be activated. *_postcache vectoring points
8266 are not yet supported.
8268 uri: icap://servername:port/servicepath
8269 ICAP server and service location.
8271 ICAP does not allow a single service to handle both REQMOD and RESPMOD
8272 transactions. Squid does not enforce that requirement. You can specify
8273 services with the same service_url and different vectoring_points. You
8274 can even specify multiple identical services as long as their
8275 service_names differ.
8277 To activate a service, use the adaptation_access directive. To group
8278 services, use adaptation_service_chain and adaptation_service_set.
8280 Service options are separated by white space. ICAP services support
8281 the following name=value options:
8284 If set to 'on' or '1', the ICAP service is treated as
8285 optional. If the service cannot be reached or malfunctions,
8286 Squid will try to ignore any errors and process the message as
8287 if the service was not enabled. No all ICAP errors can be
8288 bypassed. If set to 0, the ICAP service is treated as
8289 essential and all ICAP errors will result in an error page
8290 returned to the HTTP client.
8292 Bypass is off by default: services are treated as essential.
8295 If set to 'on' or '1', the ICAP service is allowed to
8296 dynamically change the current message adaptation plan by
8297 returning a chain of services to be used next. The services
8298 are specified using the X-Next-Services ICAP response header
8299 value, formatted as a comma-separated list of service names.
8300 Each named service should be configured in squid.conf. Other
8301 services are ignored. An empty X-Next-Services value results
8302 in an empty plan which ends the current adaptation.
8304 Dynamic adaptation plan may cross or cover multiple supported
8305 vectoring points in their natural processing order.
8307 Routing is not allowed by default: the ICAP X-Next-Services
8308 response header is ignored.
8311 Only has effect on split-stack systems. The default on those systems
8312 is to use IPv4-only connections. When set to 'on' this option will
8313 make Squid use IPv6-only connections to contact this ICAP service.
8315 on-overload=block|bypass|wait|force
8316 If the service Max-Connections limit has been reached, do
8317 one of the following for each new ICAP transaction:
8318 * block: send an HTTP error response to the client
8319 * bypass: ignore the "over-connected" ICAP service
8320 * wait: wait (in a FIFO queue) for an ICAP connection slot
8321 * force: proceed, ignoring the Max-Connections limit
8323 In SMP mode with N workers, each worker assumes the service
8324 connection limit is Max-Connections/N, even though not all
8325 workers may use a given service.
8327 The default value is "bypass" if service is bypassable,
8328 otherwise it is set to "wait".
8332 Use the given number as the Max-Connections limit, regardless
8333 of the Max-Connections value given by the service, if any.
8335 Older icap_service format without optional named parameters is
8336 deprecated but supported for backward compatibility.
8339 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
8340 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
8344 TYPE: icap_class_type
8349 This deprecated option was documented to define an ICAP service
8350 chain, even though it actually defined a set of similar, redundant
8351 services, and the chains were not supported.
8353 To define a set of redundant services, please use the
8354 adaptation_service_set directive. For service chains, use
8355 adaptation_service_chain.
8359 TYPE: icap_access_type
8364 This option is deprecated. Please use adaptation_access, which
8365 has the same ICAP functionality, but comes with better
8366 documentation, and eCAP support.
8371 -----------------------------------------------------------------------------
8378 LOC: Adaptation::Ecap::TheConfig.onoff
8381 Controls whether eCAP support is enabled.
8385 TYPE: ecap_service_type
8387 LOC: Adaptation::Ecap::TheConfig
8390 Defines a single eCAP service
8392 ecap_service id vectoring_point uri [option ...]
8395 an opaque identifier or name which is used to direct traffic to
8396 this specific service. Must be unique among all adaptation
8397 services in squid.conf.
8399 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8400 This specifies at which point of transaction processing the
8401 eCAP service should be activated. *_postcache vectoring points
8402 are not yet supported.
8404 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
8405 Squid uses the eCAP service URI to match this configuration
8406 line with one of the dynamically loaded services. Each loaded
8407 eCAP service must have a unique URI. Obtain the right URI from
8408 the service provider.
8410 To activate a service, use the adaptation_access directive. To group
8411 services, use adaptation_service_chain and adaptation_service_set.
8413 Service options are separated by white space. eCAP services support
8414 the following name=value options:
8417 If set to 'on' or '1', the eCAP service is treated as optional.
8418 If the service cannot be reached or malfunctions, Squid will try
8419 to ignore any errors and process the message as if the service
8420 was not enabled. No all eCAP errors can be bypassed.
8421 If set to 'off' or '0', the eCAP service is treated as essential
8422 and all eCAP errors will result in an error page returned to the
8425 Bypass is off by default: services are treated as essential.
8428 If set to 'on' or '1', the eCAP service is allowed to
8429 dynamically change the current message adaptation plan by
8430 returning a chain of services to be used next.
8432 Dynamic adaptation plan may cross or cover multiple supported
8433 vectoring points in their natural processing order.
8435 Routing is not allowed by default.
8437 Older ecap_service format without optional named parameters is
8438 deprecated but supported for backward compatibility.
8442 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
8443 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
8446 NAME: loadable_modules
8448 IFDEF: USE_LOADABLE_MODULES
8449 LOC: Config.loadable_module_names
8452 Instructs Squid to load the specified dynamic module(s) or activate
8453 preloaded module(s).
8455 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
8459 MESSAGE ADAPTATION OPTIONS
8460 -----------------------------------------------------------------------------
8463 NAME: adaptation_service_set
8464 TYPE: adaptation_service_set_type
8465 IFDEF: USE_ADAPTATION
8470 Configures an ordered set of similar, redundant services. This is
8471 useful when hot standby or backup adaptation servers are available.
8473 adaptation_service_set set_name service_name1 service_name2 ...
8475 The named services are used in the set declaration order. The first
8476 applicable adaptation service from the set is used first. The next
8477 applicable service is tried if and only if the transaction with the
8478 previous service fails and the message waiting to be adapted is still
8481 When adaptation starts, broken services are ignored as if they were
8482 not a part of the set. A broken service is a down optional service.
8484 The services in a set must be attached to the same vectoring point
8485 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8487 If all services in a set are optional then adaptation failures are
8488 bypassable. If all services in the set are essential, then a
8489 transaction failure with one service may still be retried using
8490 another service from the set, but when all services fail, the master
8491 transaction fails as well.
8493 A set may contain a mix of optional and essential services, but that
8494 is likely to lead to surprising results because broken services become
8495 ignored (see above), making previously bypassable failures fatal.
8496 Technically, it is the bypassability of the last failed service that
8499 See also: adaptation_access adaptation_service_chain
8502 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
8503 adaptation service_set svcLogger loggerLocal loggerRemote
8506 NAME: adaptation_service_chain
8507 TYPE: adaptation_service_chain_type
8508 IFDEF: USE_ADAPTATION
8513 Configures a list of complementary services that will be applied
8514 one-by-one, forming an adaptation chain or pipeline. This is useful
8515 when Squid must perform different adaptations on the same message.
8517 adaptation_service_chain chain_name service_name1 svc_name2 ...
8519 The named services are used in the chain declaration order. The first
8520 applicable adaptation service from the chain is used first. The next
8521 applicable service is applied to the successful adaptation results of
8522 the previous service in the chain.
8524 When adaptation starts, broken services are ignored as if they were
8525 not a part of the chain. A broken service is a down optional service.
8527 Request satisfaction terminates the adaptation chain because Squid
8528 does not currently allow declaration of RESPMOD services at the
8529 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8531 The services in a chain must be attached to the same vectoring point
8532 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8534 A chain may contain a mix of optional and essential services. If an
8535 essential adaptation fails (or the failure cannot be bypassed for
8536 other reasons), the master transaction fails. Otherwise, the failure
8537 is bypassed as if the failed adaptation service was not in the chain.
8539 See also: adaptation_access adaptation_service_set
8542 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8545 NAME: adaptation_access
8546 TYPE: adaptation_access_type
8547 IFDEF: USE_ADAPTATION
8550 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8552 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8554 adaptation_access service_name allow|deny [!]aclname...
8555 adaptation_access set_name allow|deny [!]aclname...
8557 At each supported vectoring point, the adaptation_access
8558 statements are processed in the order they appear in this
8559 configuration file. Statements pointing to the following services
8560 are ignored (i.e., skipped without checking their ACL):
8562 - services serving different vectoring points
8563 - "broken-but-bypassable" services
8564 - "up" services configured to ignore such transactions
8565 (e.g., based on the ICAP Transfer-Ignore header).
8567 When a set_name is used, all services in the set are checked
8568 using the same rules, to find the first applicable one. See
8569 adaptation_service_set for details.
8571 If an access list is checked and there is a match, the
8572 processing stops: For an "allow" rule, the corresponding
8573 adaptation service is used for the transaction. For a "deny"
8574 rule, no adaptation service is activated.
8576 It is currently not possible to apply more than one adaptation
8577 service at the same vectoring point to the same HTTP transaction.
8579 See also: icap_service and ecap_service
8582 adaptation_access service_1 allow all
8585 NAME: adaptation_service_iteration_limit
8587 IFDEF: USE_ADAPTATION
8588 LOC: Adaptation::Config::service_iteration_limit
8591 Limits the number of iterations allowed when applying adaptation
8592 services to a message. If your longest adaptation set or chain
8593 may have more than 16 services, increase the limit beyond its
8594 default value of 16. If detecting infinite iteration loops sooner
8595 is critical, make the iteration limit match the actual number
8596 of services in your longest adaptation set or chain.
8598 Infinite adaptation loops are most likely with routing services.
8600 See also: icap_service routing=1
8603 NAME: adaptation_masterx_shared_names
8605 IFDEF: USE_ADAPTATION
8606 LOC: Adaptation::Config::masterx_shared_name
8609 For each master transaction (i.e., the HTTP request and response
8610 sequence, including all related ICAP and eCAP exchanges), Squid
8611 maintains a table of metadata. The table entries are (name, value)
8612 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8613 with the master transaction.
8615 This option specifies the table entry names that Squid must accept
8616 from and forward to the adaptation transactions.
8618 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8619 shared table by returning an ICAP header field with a name
8620 specified in adaptation_masterx_shared_names.
8622 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8623 shared table by implementing the libecap::visitEachOption() API
8624 to provide an option with a name specified in
8625 adaptation_masterx_shared_names.
8627 Squid will store and forward the set entry to subsequent adaptation
8628 transactions within the same master transaction scope.
8630 Only one shared entry name is supported at this time.
8633 # share authentication information among ICAP services
8634 adaptation_masterx_shared_names X-Subscriber-ID
8637 NAME: adaptation_meta
8639 IFDEF: USE_ADAPTATION
8640 LOC: Adaptation::Config::metaHeaders
8643 This option allows Squid administrator to add custom ICAP request
8644 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8645 Use it to pass custom authentication tokens and other
8646 transaction-state related meta information to an ICAP/eCAP service.
8648 The addition of a meta header is ACL-driven:
8649 adaptation_meta name value [!]aclname ...
8651 Processing for a given header name stops after the first ACL list match.
8652 Thus, it is impossible to add two headers with the same name. If no ACL
8653 lists match for a given header name, no such header is added. For
8656 # do not debug transactions except for those that need debugging
8657 adaptation_meta X-Debug 1 needs_debugging
8659 # log all transactions except for those that must remain secret
8660 adaptation_meta X-Log 1 !keep_secret
8662 # mark transactions from users in the "G 1" group
8663 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8665 The "value" parameter may be a regular squid.conf token or a "double
8666 quoted string". Within the quoted string, use backslash (\) to escape
8667 any character, which is currently only useful for escaping backslashes
8668 and double quotes. For example,
8669 "this string has one backslash (\\) and two \"quotes\""
8671 Used adaptation_meta header values may be logged via %note
8672 logformat code. If multiple adaptation_meta headers with the same name
8673 are used during master transaction lifetime, the header values are
8674 logged in the order they were used and duplicate values are ignored
8675 (only the first repeated value will be logged).
8681 LOC: Adaptation::Icap::TheConfig.repeat
8682 DEFAULT_IF_NONE: deny all
8684 This ACL determines which retriable ICAP transactions are
8685 retried. Transactions that received a complete ICAP response
8686 and did not have to consume or produce HTTP bodies to receive
8687 that response are usually retriable.
8689 icap_retry allow|deny [!]aclname ...
8691 Squid automatically retries some ICAP I/O timeouts and errors
8692 due to persistent connection race conditions.
8694 See also: icap_retry_limit
8697 NAME: icap_retry_limit
8700 LOC: Adaptation::Icap::TheConfig.repeat_limit
8702 DEFAULT_DOC: No retries are allowed.
8704 Limits the number of retries allowed.
8706 Communication errors due to persistent connection race
8707 conditions are unavoidable, automatically retried, and do not
8708 count against this limit.
8710 See also: icap_retry
8716 -----------------------------------------------------------------------------
8719 NAME: check_hostnames
8722 LOC: Config.onoff.check_hostnames
8724 For security and stability reasons Squid can check
8725 hostnames for Internet standard RFC compliance. If you want
8726 Squid to perform these checks turn this directive on.
8729 NAME: allow_underscore
8732 LOC: Config.onoff.allow_underscore
8734 Underscore characters is not strictly allowed in Internet hostnames
8735 but nevertheless used by many sites. Set this to off if you want
8736 Squid to be strict about the standard.
8737 This check is performed only when check_hostnames is set to on.
8740 NAME: dns_retransmit_interval
8743 LOC: Config.Timeout.idns_retransmit
8745 Initial retransmit interval for DNS queries. The interval is
8746 doubled each time all configured DNS servers have been tried.
8752 LOC: Config.Timeout.idns_query
8754 DNS Query timeout. If no response is received to a DNS query
8755 within this time all DNS servers for the queried domain
8756 are assumed to be unavailable.
8759 NAME: dns_packet_max
8761 DEFAULT_DOC: EDNS disabled
8763 LOC: Config.dns.packet_max
8765 Maximum number of bytes packet size to advertise via EDNS.
8766 Set to "none" to disable EDNS large packet support.
8768 For legacy reasons DNS UDP replies will default to 512 bytes which
8769 is too small for many responses. EDNS provides a means for Squid to
8770 negotiate receiving larger responses back immediately without having
8771 to failover with repeat requests. Responses larger than this limit
8772 will retain the old behaviour of failover to TCP DNS.
8774 Squid has no real fixed limit internally, but allowing packet sizes
8775 over 1500 bytes requires network jumbogram support and is usually not
8778 WARNING: The RFC also indicates that some older resolvers will reply
8779 with failure of the whole request if the extension is added. Some
8780 resolvers have already been identified which will reply with mangled
8781 EDNS response on occasion. Usually in response to many-KB jumbogram
8782 sizes being advertised by Squid.
8783 Squid will currently treat these both as an unable-to-resolve domain
8784 even if it would be resolvable without EDNS.
8791 DEFAULT_DOC: Search for single-label domain names is disabled.
8792 LOC: Config.onoff.res_defnames
8794 Normally the RES_DEFNAMES resolver option is disabled
8795 (see res_init(3)). This prevents caches in a hierarchy
8796 from interpreting single-component hostnames locally. To allow
8797 Squid to handle single-component names, enable this option.
8800 NAME: dns_multicast_local
8804 DEFAULT_DOC: Search for .local and .arpa names is disabled.
8805 LOC: Config.onoff.dns_mdns
8807 When set to on, Squid sends multicast DNS lookups on the local
8808 network for domains ending in .local and .arpa.
8809 This enables local servers and devices to be contacted in an
8810 ad-hoc or zero-configuration network environment.
8813 NAME: dns_nameservers
8816 DEFAULT_DOC: Use operating system definitions
8817 LOC: Config.dns_nameservers
8819 Use this if you want to specify a list of DNS name servers
8820 (IP addresses) to use instead of those given in your
8821 /etc/resolv.conf file.
8823 On Windows platforms, if no value is specified here or in
8824 the /etc/resolv.conf file, the list of DNS name servers are
8825 taken from the Windows registry, both static and dynamic DHCP
8826 configurations are supported.
8828 Example: dns_nameservers 10.0.0.1 192.172.0.4
8833 DEFAULT: @DEFAULT_HOSTS@
8834 LOC: Config.etcHostsPath
8836 Location of the host-local IP name-address associations
8837 database. Most Operating Systems have such a file on different
8839 - Un*X & Linux: /etc/hosts
8840 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
8841 (%SystemRoot% value install default is c:\winnt)
8842 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
8843 (%SystemRoot% value install default is c:\windows)
8844 - Windows 9x/Me: %windir%\hosts
8845 (%windir% value is usually c:\windows)
8846 - Cygwin: /etc/hosts
8848 The file contains newline-separated definitions, in the
8849 form ip_address_in_dotted_form name [name ...] names are
8850 whitespace-separated. Lines beginning with an hash (#)
8851 character are comments.
8853 The file is checked at startup and upon configuration.
8854 If set to 'none', it won't be checked.
8855 If append_domain is used, that domain will be added to
8856 domain-local (i.e. not containing any dot character) host
8862 LOC: Config.appendDomain
8864 DEFAULT_DOC: Use operating system definitions
8866 Appends local domain name to hostnames without any dots in
8867 them. append_domain must begin with a period.
8869 Be warned there are now Internet names with no dots in
8870 them using only top-domain names, so setting this may
8871 cause some Internet sites to become unavailable.
8874 append_domain .yourdomain.com
8877 NAME: ignore_unknown_nameservers
8879 LOC: Config.onoff.ignore_unknown_nameservers
8882 By default Squid checks that DNS responses are received
8883 from the same IP addresses they are sent to. If they
8884 don't match, Squid ignores the response and writes a warning
8885 message to cache.log. You can allow responses from unknown
8886 nameservers by setting this option to 'off'.
8892 LOC: Config.dns.v4_first
8894 With the IPv6 Internet being as fast or faster than IPv4 Internet
8895 for most networks Squid prefers to contact websites over IPv6.
8897 This option reverses the order of preference to make Squid contact
8898 dual-stack websites over IPv4 first. Squid will still perform both
8899 IPv6 and IPv4 DNS lookups before connecting.
8902 This option will restrict the situations under which IPv6
8903 connectivity is used (and tested). Hiding network problems
8904 which would otherwise be detected and warned about.
8908 COMMENT: (number of entries)
8911 LOC: Config.ipcache.size
8913 Maximum number of DNS IP cache entries.
8920 LOC: Config.ipcache.low
8927 LOC: Config.ipcache.high
8929 The size, low-, and high-water marks for the IP cache.
8932 NAME: fqdncache_size
8933 COMMENT: (number of entries)
8936 LOC: Config.fqdncache.size
8938 Maximum number of FQDN cache entries.
8943 -----------------------------------------------------------------------------
8946 NAME: configuration_includes_quoted_values
8948 TYPE: configuration_includes_quoted_values
8950 LOC: ConfigParser::RecognizeQuotedValues
8952 If set, Squid will recognize each "quoted string" after a configuration
8953 directive as a single parameter. The quotes are stripped before the
8954 parameter value is interpreted or used.
8955 See "Values with spaces, quotes, and other special characters"
8956 section for more details.
8963 LOC: Config.onoff.mem_pools
8965 If set, Squid will keep pools of allocated (but unused) memory
8966 available for future use. If memory is a premium on your
8967 system and you believe your malloc library outperforms Squid
8968 routines, disable this.
8971 NAME: memory_pools_limit
8975 LOC: Config.MemPools.limit
8977 Used only with memory_pools on:
8978 memory_pools_limit 50 MB
8980 If set to a non-zero value, Squid will keep at most the specified
8981 limit of allocated (but unused) memory in memory pools. All free()
8982 requests that exceed this limit will be handled by your malloc
8983 library. Squid does not pre-allocate any memory, just safe-keeps
8984 objects that otherwise would be free()d. Thus, it is safe to set
8985 memory_pools_limit to a reasonably high value even if your
8986 configuration will use less memory.
8988 If set to none, Squid will keep all memory it can. That is, there
8989 will be no limit on the total amount of memory used for safe-keeping.
8991 To disable memory allocation optimization, do not set
8992 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
8994 An overhead for maintaining memory pools is not taken into account
8995 when the limit is checked. This overhead is close to four bytes per
8996 object kept. However, pools may actually _save_ memory because of
8997 reduced memory thrashing in your malloc library.
9001 COMMENT: on|off|transparent|truncate|delete
9004 LOC: opt_forwarded_for
9006 If set to "on", Squid will append your client's IP address
9007 in the HTTP requests it forwards. By default it looks like:
9009 X-Forwarded-For: 192.1.2.3
9011 If set to "off", it will appear as
9013 X-Forwarded-For: unknown
9015 If set to "transparent", Squid will not alter the
9016 X-Forwarded-For header in any way.
9018 If set to "delete", Squid will delete the entire
9019 X-Forwarded-For header.
9021 If set to "truncate", Squid will remove all existing
9022 X-Forwarded-For entries, and place the client IP as the sole entry.
9025 NAME: cachemgr_passwd
9026 TYPE: cachemgrpasswd
9028 DEFAULT_DOC: No password. Actions which require password are denied.
9029 LOC: Config.passwd_list
9031 Specify passwords for cachemgr operations.
9033 Usage: cachemgr_passwd password action action ...
9035 Some valid actions are (see cache manager menu for a full list):
9075 * Indicates actions which will not be performed without a
9076 valid password, others can be performed if not listed here.
9078 To disable an action, set the password to "disable".
9079 To allow performing an action without a password, set the
9082 Use the keyword "all" to set the same password for all actions.
9085 cachemgr_passwd secret shutdown
9086 cachemgr_passwd lesssssssecret info stats/objects
9087 cachemgr_passwd disable all
9094 LOC: Config.onoff.client_db
9096 If you want to disable collecting per-client statistics,
9097 turn off client_db here.
9100 NAME: refresh_all_ims
9104 LOC: Config.onoff.refresh_all_ims
9106 When you enable this option, squid will always check
9107 the origin server for an update when a client sends an
9108 If-Modified-Since request. Many browsers use IMS
9109 requests when the user requests a reload, and this
9110 ensures those clients receive the latest version.
9112 By default (off), squid may return a Not Modified response
9113 based on the age of the cached version.
9116 NAME: reload_into_ims
9117 IFDEF: USE_HTTP_VIOLATIONS
9121 LOC: Config.onoff.reload_into_ims
9123 When you enable this option, client no-cache or ``reload''
9124 requests will be changed to If-Modified-Since requests.
9125 Doing this VIOLATES the HTTP standard. Enabling this
9126 feature could make you liable for problems which it
9129 see also refresh_pattern for a more selective approach.
9132 NAME: connect_retries
9134 LOC: Config.connect_retries
9136 DEFAULT_DOC: Do not retry failed connections.
9138 This sets the maximum number of connection attempts made for each
9139 TCP connection. The connect_retries attempts must all still
9140 complete within the connection timeout period.
9142 The default is not to re-try if the first connection attempt fails.
9143 The (not recommended) maximum is 10 tries.
9145 A warning message will be generated if it is set to a too-high
9146 value and the configured value will be over-ridden.
9148 Note: These re-tries are in addition to forward_max_tries
9149 which limit how many different addresses may be tried to find
9153 NAME: retry_on_error
9155 LOC: Config.retry.onerror
9158 If set to ON Squid will automatically retry requests when
9159 receiving an error response with status 403 (Forbidden),
9160 500 (Internal Error), 501 or 503 (Service not available).
9161 Status 502 and 504 (Gateway errors) are always retried.
9163 This is mainly useful if you are in a complex cache hierarchy to
9164 work around access control errors.
9166 NOTE: This retry will attempt to find another working destination.
9167 Which is different from the server which just failed.
9170 NAME: as_whois_server
9172 LOC: Config.as_whois_server
9173 DEFAULT: whois.ra.net
9175 WHOIS server to query for AS numbers. NOTE: AS numbers are
9176 queried only when Squid starts up, not for every request.
9181 LOC: Config.onoff.offline
9184 Enable this option and Squid will never try to validate cached
9188 NAME: uri_whitespace
9189 TYPE: uri_whitespace
9190 LOC: Config.uri_whitespace
9193 What to do with requests that have whitespace characters in the
9196 strip: The whitespace characters are stripped out of the URL.
9197 This is the behavior recommended by RFC2396 and RFC3986
9198 for tolerant handling of generic URI.
9199 NOTE: This is one difference between generic URI and HTTP URLs.
9201 deny: The request is denied. The user receives an "Invalid
9203 This is the behaviour recommended by RFC2616 for safe
9204 handling of HTTP request URL.
9206 allow: The request is allowed and the URI is not changed. The
9207 whitespace characters remain in the URI. Note the
9208 whitespace is passed to redirector processes if they
9210 Note this may be considered a violation of RFC2616
9211 request parsing where whitespace is prohibited in the
9214 encode: The request is allowed and the whitespace characters are
9215 encoded according to RFC1738.
9217 chop: The request is allowed and the URI is chopped at the
9221 NOTE the current Squid implementation of encode and chop violates
9222 RFC2616 by not using a 301 redirect after altering the URL.
9227 LOC: Config.chroot_dir
9230 Specifies a directory where Squid should do a chroot() while
9231 initializing. This also causes Squid to fully drop root
9232 privileges after initializing. This means, for example, if you
9233 use a HTTP port less than 1024 and try to reconfigure, you may
9234 get an error saying that Squid can not open the port.
9237 NAME: balance_on_multiple_ip
9239 LOC: Config.onoff.balance_on_multiple_ip
9242 Modern IP resolvers in squid sort lookup results by preferred access.
9243 By default squid will use these IP in order and only rotates to
9244 the next listed when the most preffered fails.
9246 Some load balancing servers based on round robin DNS have been
9247 found not to preserve user session state across requests
9248 to different IP addresses.
9250 Enabling this directive Squid rotates IP's per request.
9253 NAME: pipeline_prefetch
9254 TYPE: pipelinePrefetch
9255 LOC: Config.pipeline_max_prefetch
9257 DEFAULT_DOC: Do not pre-parse pipelined requests.
9259 HTTP clients may send a pipeline of 1+N requests to Squid using a
9260 single connection, without waiting for Squid to respond to the first
9261 of those requests. This option limits the number of concurrent
9262 requests Squid will try to handle in parallel. If set to N, Squid
9263 will try to receive and process up to 1+N requests on the same
9264 connection concurrently.
9266 Defaults to 0 (off) for bandwidth management and access logging
9269 NOTE: pipelining requires persistent connections to clients.
9271 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
9274 NAME: high_response_time_warning
9277 LOC: Config.warnings.high_rptm
9279 DEFAULT_DOC: disabled.
9281 If the one-minute median response time exceeds this value,
9282 Squid prints a WARNING with debug level 0 to get the
9283 administrators attention. The value is in milliseconds.
9286 NAME: high_page_fault_warning
9288 LOC: Config.warnings.high_pf
9290 DEFAULT_DOC: disabled.
9292 If the one-minute average page fault rate exceeds this
9293 value, Squid prints a WARNING with debug level 0 to get
9294 the administrators attention. The value is in page faults
9298 NAME: high_memory_warning
9300 LOC: Config.warnings.high_memory
9301 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
9303 DEFAULT_DOC: disabled.
9305 If the memory usage (as determined by gnumalloc, if available and used)
9306 exceeds this amount, Squid prints a WARNING with debug level 0 to get
9307 the administrators attention.
9309 # TODO: link high_memory_warning to mempools?
9311 NAME: sleep_after_fork
9312 COMMENT: (microseconds)
9314 LOC: Config.sleep_after_fork
9317 When this is set to a non-zero value, the main Squid process
9318 sleeps the specified number of microseconds after a fork()
9319 system call. This sleep may help the situation where your
9320 system reports fork() failures due to lack of (virtual)
9321 memory. Note, however, if you have a lot of child
9322 processes, these sleep delays will add up and your
9323 Squid will not service requests for some amount of time
9324 until all the child processes have been started.
9325 On Windows value less then 1000 (1 milliseconds) are
9329 NAME: windows_ipaddrchangemonitor
9330 IFDEF: _SQUID_WINDOWS_
9334 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
9336 On Windows Squid by default will monitor IP address changes and will
9337 reconfigure itself after any detected event. This is very useful for
9338 proxies connected to internet with dial-up interfaces.
9339 In some cases (a Proxy server acting as VPN gateway is one) it could be
9340 desiderable to disable this behaviour setting this to 'off'.
9341 Note: after changing this, Squid service must be restarted.
9346 IFDEF: USE_SQUID_EUI
9348 LOC: Eui::TheConfig.euiLookup
9350 Whether to lookup the EUI or MAC address of a connected client.
9353 NAME: max_filedescriptors max_filedesc
9356 DEFAULT_DOC: Use operating system limits set by ulimit.
9357 LOC: Config.max_filedescriptors
9359 Reduce the maximum number of filedescriptors supported below
9360 the usual operating system defaults.
9362 Remove from squid.conf to inherit the current ulimit setting.
9364 Note: Changing this requires a restart of Squid. Also
9365 not all I/O types supports large values (eg on Windows).
9372 DEFAULT_DOC: SMP support disabled.
9374 Number of main Squid processes or "workers" to fork and maintain.
9375 0: "no daemon" mode, like running "squid -N ..."
9376 1: "no SMP" mode, start one main Squid process daemon (default)
9377 N: start N main Squid process daemons (i.e., SMP mode)
9379 In SMP mode, each worker does nearly all what a single Squid daemon
9380 does (e.g., listen on http_port and forward HTTP requests).
9383 NAME: cpu_affinity_map
9384 TYPE: CpuAffinityMap
9385 LOC: Config.cpuAffinityMap
9387 DEFAULT_DOC: Let operating system decide.
9389 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
9391 Sets 1:1 mapping between Squid processes and CPU cores. For example,
9393 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
9395 affects processes 1 through 4 only and places them on the first
9396 four even cores, starting with core #1.
9398 CPU cores are numbered starting from 1. Requires support for
9399 sched_getaffinity(2) and sched_setaffinity(2) system calls.
9401 Multiple cpu_affinity_map options are merged.
9406 NAME: force_request_body_continuation
9408 LOC: Config.accessList.forceRequestBodyContinuation
9410 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
9412 This option controls how Squid handles data upload requests from HTTP
9413 and FTP agents that require a "Please Continue" control message response
9414 to actually send the request body to Squid. It is mostly useful in
9415 adaptation environments.
9417 When Squid receives an HTTP request with an "Expect: 100-continue"
9418 header or an FTP upload command (e.g., STOR), Squid normally sends the
9419 request headers or FTP command information to an adaptation service (or
9420 peer) and waits for a response. Most adaptation services (and some
9421 broken peers) may not respond to Squid at that stage because they may
9422 decide to wait for the HTTP request body or FTP data transfer. However,
9423 that request body or data transfer may never come because Squid has not
9424 responded with the HTTP 100 or FTP 150 (Please Continue) control message
9425 to the request sender yet!
9427 An allow match tells Squid to respond with the HTTP 100 or FTP 150
9428 (Please Continue) control message on its own, before forwarding the
9429 request to an adaptation service or peer. Such a response usually forces
9430 the request sender to proceed with sending the body. A deny match tells
9431 Squid to delay that control response until the origin server confirms
9432 that the request body is needed. Delaying is the default behavior.