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
68 Values with spaces, quotes, and other special characters
70 Squid supports directive parameters with spaces, quotes, and other
71 special characters. Surround such parameters with "double quotes". Use
72 the configuration_includes_quoted_values directive to enable or
75 Squid supports reading configuration option parameters from external
76 files using the syntax:
77 parameters("/path/filename")
79 acl whitelist dstdomain parameters("/etc/squid/whitelist.txt")
81 Conditional configuration
83 If-statements can be used to make configuration directives
87 ... regular configuration directives ...
89 ... regular configuration directives ...]
92 The else part is optional. The keywords "if", "else", and "endif"
93 must be typed on their own lines, as if they were regular
94 configuration directives.
96 NOTE: An else-if condition is not supported.
98 These individual conditions types are supported:
101 Always evaluates to true.
103 Always evaluates to false.
104 <integer> = <integer>
105 Equality comparison of two integer numbers.
110 The following SMP-related preprocessor macros can be used.
112 ${process_name} expands to the current Squid process "name"
113 (e.g., squid1, squid2, or cache1).
115 ${process_number} expands to the current Squid process
116 identifier, which is an integer number (e.g., 1, 2, 3) unique
117 across all Squid processes of the current service instance.
119 ${service_name} expands into the current Squid service instance
120 name identifier which is provided by -n on the command line.
124 # options still not yet ported from 2.7 to 3.x
125 NAME: broken_vary_encoding
128 This option is not yet supported by Squid-3.
134 This option is not yet supported by Squid-3.
140 This option is not yet supported by Squid-3.
143 NAME: external_refresh_check
146 This option is not yet supported by Squid-3.
149 NAME: location_rewrite_program location_rewrite_access location_rewrite_children location_rewrite_concurrency
152 This option is not yet supported by Squid-3.
155 NAME: refresh_stale_hit
158 This option is not yet supported by Squid-3.
161 # Options Removed in 3.3
162 NAME: ignore_ims_on_miss
165 Remove this line. The HTTP/1.1 feature is now fully supported by default.
168 # Options Removed in 3.2
169 NAME: ignore_expect_100
172 Remove this line. The HTTP/1.1 feature is now fully supported by default.
175 NAME: dns_v4_fallback
178 Remove this line. Squid performs a 'Happy Eyeballs' algorithm, the 'fallback' algorithm is no longer relevant.
184 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
187 NAME: maximum_single_addr_tries
190 Replaced by connect_retries. The behaviour has changed, please read the documentation before altering.
196 Remove this line. The feature is supported by default in storage types where update is implemented.
199 NAME: url_rewrite_concurrency
202 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
205 # Options Removed in 3.1
209 Remove this line. DNS is no longer tested on startup.
212 NAME: extension_methods
215 Remove this line. All valid methods for HTTP are accepted by default.
218 # 2.7 Options Removed/Replaced in 3.2
223 # 2.7 Options Removed/Replaced in 3.1
231 Remove this line. HTTP/1.1 is supported by default.
234 NAME: upgrade_http0.9
237 Remove this line. ICY/1.0 streaming protocol is supported by default.
240 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
243 Alter these entries. Use the qos_flows directive instead.
246 # Options Removed in 3.0
250 Since squid-3.0 replace with request_header_access or reply_header_access
251 depending on whether you wish to match client requests or server replies.
254 NAME: httpd_accel_no_pmtu_disc
257 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
260 NAME: wais_relay_host
263 Replace this line with 'cache_peer' configuration.
266 NAME: wais_relay_port
269 Replace this line with 'cache_peer' configuration.
273 OPTIONS FOR AUTHENTICATION
274 -----------------------------------------------------------------------------
283 This is used to define parameters for the various authentication
284 schemes supported by Squid.
286 format: auth_param scheme parameter [setting]
288 The order in which authentication schemes are presented to the client is
289 dependent on the order the scheme first appears in config file. IE
290 has a bug (it's not RFC 2617 compliant) in that it will use the basic
291 scheme if basic is the first entry presented, even if more secure
292 schemes are presented. For now use the order in the recommended
293 settings section below. If other browsers have difficulties (don't
294 recognize the schemes offered even if you are using basic) either
295 put basic first, or disable the other schemes (by commenting out their
298 Once an authentication scheme is fully configured, it can only be
299 shutdown by shutting squid down and restarting. Changes can be made on
300 the fly and activated with a reconfigure. I.E. You can change to a
301 different helper, but not unconfigure the helper completely.
303 Please note that while this directive defines how Squid processes
304 authentication it does not automatically activate authentication.
305 To use authentication you must in addition make use of ACLs based
306 on login name in http_access (proxy_auth, proxy_auth_regex or
307 external with %LOGIN used in the format tag). The browser will be
308 challenged for authentication on the first such acl encountered
309 in http_access processing and will also be re-challenged for new
310 login credentials if the request is being denied by a proxy_auth
313 WARNING: authentication can't be used in a transparently intercepting
314 proxy as the client then thinks it is talking to an origin server and
315 not the proxy. This is a limitation of bending the TCP/IP protocol to
316 transparently intercepting port 80, not a limitation in Squid.
317 Ports flagged 'transparent', 'intercept', or 'tproxy' have
318 authentication disabled.
320 === Parameters common to all schemes. ===
323 Specifies the command for the external authenticator. Such a program
324 runs a loop that, on every iteration, reads a request line from
325 the standard and responds with a scheme-specific answer. The loop
326 stops when all input is exchausted (EOF). See scheme-specific
327 "program" descriptions below for details.
330 Specifies a string to be append to request line format for the
331 authentication helper. "Quoted" format values may contain spaces and
332 logformat %macros. In theory, any logformat %macro can be used.
333 In practice, a %macro expands as a dash (-) if the helper request is
334 sent before the required macro information is available to Squid.
335 By default, Squid uses request formats provided in scheme-specific
336 examples below (search for %credentials).
337 The expanded key_extras value is added to the Squid credentials
338 cache and, hence, will affect authentication. It can be used to
339 autenticate different users with identical user names (e.g., when user
340 authentication depends on http_port).
341 Avoid adding frequently changing information to key_extras. For
342 example, if you add user source IP, and it changes frequently
343 in your environment, then max_user_ip ACL is going to treat every
344 user+IP combination as a unique "user", breaking the ACL and
345 wasting a lot of memory on those user records. It will also force
346 users to authenticate from scratch whenever their IP changes.
348 === Parameters for the basic scheme follow. ===
351 Specify the command for the external authenticator. Such a program
352 reads a request_format line ("username password" by default) and
353 replies with one of three results:
359 the user does not exist.
362 An internal error occurred in the helper, preventing
363 a result being identified.
365 "ERR" and "BH" results may optionally be followed by message="..."
366 containing a description available as %m in the returned error page.
368 If you use an authenticator, make sure you have 1 acl of type
371 By default, the basic authentication scheme is not used unless a
372 program is specified.
374 If you want to use the traditional NCSA proxy authentication, set
375 this line to something like
377 auth_param basic program @DEFAULT_PREFIX@/libexec/basic_ncsa_auth @DEFAULT_PREFIX@/etc/passwd
380 HTTP uses iso-latin-1 as character set, while some authentication
381 backends such as LDAP expects UTF-8. If this is set to on Squid will
382 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
383 username & password to the helper.
385 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
386 The maximum number of authenticator processes to spawn. If you start too few
387 Squid will have to wait for them to process a backlog of credential
388 verifications, slowing it down. When password verifications are
389 done via a (slow) network you are likely to need lots of
390 authenticator processes.
392 The startup= and idle= options permit some skew in the exact amount
393 run. A minimum of startup=N will begin during startup and reconfigure.
394 Squid will start more in groups of up to idle=N in an attempt to meet
395 traffic needs and to keep idle=N free above those traffic needs up to
398 The concurrency= option sets the number of concurrent requests the
399 helper can process. The default of 0 is used for helpers who only
400 supports one request at a time. Setting this to a number greater than
401 0 changes the protocol used to include a channel number first on the
402 request/response line, allowing multiple requests to be sent to the
403 same helper in parallel without waiting for the response.
404 Must not be set unless it's known the helper supports this.
406 auth_param basic children 20 startup=0 idle=1
409 Specifies the realm name which is to be reported to the
410 client for the basic proxy authentication scheme (part of
411 the text the user will see when prompted their username and
412 password). There is no default.
413 auth_param basic realm Squid proxy-caching web server
415 "credentialsttl" timetolive
416 Specifies how long squid assumes an externally validated
417 username:password pair is valid for - in other words how
418 often the helper program is called for that user. Set this
419 low to force revalidation with short lived passwords. Note
420 setting this high does not impact your susceptibility
421 to replay attacks unless you are using an one-time password
422 system (such as SecureID). If you are using such a system,
423 you will be vulnerable to replay attacks unless you also
424 use the max_user_ip ACL in an http_access rule.
426 "casesensitive" on|off
427 Specifies if usernames are case sensitive. Most user databases are
428 case insensitive allowing the same username to be spelled using both
429 lower and upper case letters, but some are case sensitive. This
430 makes a big difference for user_max_ip ACL processing and similar.
431 auth_param basic casesensitive off
433 === Parameters for the digest scheme follow ===
436 Specify the command for the external authenticator. Such a program
437 reads a request_format line ("username":"realm" by default) and
438 replies with one of three results:
441 the user exists. The ha1= key is mandatory and
442 contains the appropriate H(A1) value, hex encoded.
443 See rfc 2616 for the definition of H(A1).
446 the user does not exist.
449 An internal error occurred in the helper, preventing
450 a result being identified.
452 "ERR" and "BH" results may optionally be followed by message="..."
453 containing a description available as %m in the returned error page.
455 By default, the digest authentication scheme is not used unless a
456 program is specified.
458 If you want to use a digest authenticator, set this line to
461 auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass
464 HTTP uses iso-latin-1 as character set, while some authentication
465 backends such as LDAP expects UTF-8. If this is set to on Squid will
466 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
467 username & password to the helper.
469 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
470 The maximum number of authenticator processes to spawn (default 5).
471 If you start too few Squid will have to wait for them to
472 process a backlog of H(A1) calculations, slowing it down.
473 When the H(A1) calculations are done via a (slow) network
474 you are likely to need lots of authenticator processes.
476 The startup= and idle= options permit some skew in the exact amount
477 run. A minimum of startup=N will begin during startup and reconfigure.
478 Squid will start more in groups of up to idle=N in an attempt to meet
479 traffic needs and to keep idle=N free above those traffic needs up to
482 The concurrency= option sets the number of concurrent requests the
483 helper can process. The default of 0 is used for helpers who only
484 supports one request at a time. Setting this to a number greater than
485 0 changes the protocol used to include a channel number first on the
486 request/response line, allowing multiple requests to be sent to the
487 same helper in parallel without waiting for the response.
488 Must not be set unless it's known the helper supports this.
490 auth_param digest children 20 startup=0 idle=1
493 Specifies the realm name which is to be reported to the
494 client for the digest proxy authentication scheme (part of
495 the text the user will see when prompted their username and
496 password). There is no default.
497 auth_param digest realm Squid proxy-caching web server
499 "nonce_garbage_interval" timeinterval
500 Specifies the interval that nonces that have been issued
501 to client_agent's are checked for validity.
503 "nonce_max_duration" timeinterval
504 Specifies the maximum length of time a given nonce will be
507 "nonce_max_count" number
508 Specifies the maximum number of times a given nonce can be
511 "nonce_strictness" on|off
512 Determines if squid requires strict increment-by-1 behavior
513 for nonce counts, or just incrementing (off - for use when
514 user agents generate nonce counts that occasionally miss 1
515 (ie, 1,2,4,6)). Default off.
517 "check_nonce_count" on|off
518 This directive if set to off can disable the nonce count check
519 completely to work around buggy digest qop implementations in
520 certain mainstream browser versions. Default on to check the
521 nonce count to protect from authentication replay attacks.
523 "post_workaround" on|off
524 This is a workaround to certain buggy browsers who sends
525 an incorrect request digest in POST requests when reusing
526 the same nonce as acquired earlier on a GET request.
528 === NTLM scheme options follow ===
531 Specify the command for the external NTLM authenticator.
532 Such a program reads exchanged NTLMSSP packets with
533 the browser via Squid until authentication is completed.
534 If you use an NTLM authenticator, make sure you have 1 acl
535 of type proxy_auth. By default, the NTLM authenticator program
538 auth_param ntlm program /usr/bin/ntlm_auth
540 "children" numberofchildren [startup=N] [idle=N]
541 The maximum number of authenticator processes to spawn (default 5).
542 If you start too few Squid will have to wait for them to
543 process a backlog of credential verifications, slowing it
544 down. When credential verifications are done via a (slow)
545 network you are likely to need lots of authenticator
548 The startup= and idle= options permit some skew in the exact amount
549 run. A minimum of startup=N will begin during startup and reconfigure.
550 Squid will start more in groups of up to idle=N in an attempt to meet
551 traffic needs and to keep idle=N free above those traffic needs up to
554 auth_param ntlm children 20 startup=0 idle=1
557 If you experience problems with PUT/POST requests when using the
558 Negotiate authentication scheme then you can try setting this to
559 off. This will cause Squid to forcibly close the connection on
560 the initial requests where the browser asks which schemes are
561 supported by the proxy.
563 auth_param ntlm keep_alive on
565 === Options for configuring the NEGOTIATE auth-scheme follow ===
568 Specify the command for the external Negotiate authenticator.
569 This protocol is used in Microsoft Active-Directory enabled setups with
570 the Microsoft Internet Explorer or Mozilla Firefox browsers.
571 Its main purpose is to exchange credentials with the Squid proxy
572 using the Kerberos mechanisms.
573 If you use a Negotiate authenticator, make sure you have at least
574 one acl of type proxy_auth active. By default, the negotiate
575 authenticator program is not used.
576 The only supported program for this role is the ntlm_auth
577 program distributed as part of Samba, version 4 or later.
579 auth_param negotiate program /usr/bin/ntlm_auth --helper-protocol=gss-spnego
581 "children" numberofchildren [startup=N] [idle=N]
582 The maximum number of authenticator processes to spawn (default 5).
583 If you start too few Squid will have to wait for them to
584 process a backlog of credential verifications, slowing it
585 down. When credential verifications are done via a (slow)
586 network you are likely to need lots of authenticator
589 The startup= and idle= options permit some skew in the exact amount
590 run. A minimum of startup=N will begin during startup and reconfigure.
591 Squid will start more in groups of up to idle=N in an attempt to meet
592 traffic needs and to keep idle=N free above those traffic needs up to
595 auth_param negotiate children 20 startup=0 idle=1
598 If you experience problems with PUT/POST requests when using the
599 Negotiate authentication scheme then you can try setting this to
600 off. This will cause Squid to forcibly close the connection on
601 the initial requests where the browser asks which schemes are
602 supported by the proxy.
604 auth_param negotiate keep_alive on
608 #Recommended minimum configuration per scheme:
609 #auth_param negotiate program <uncomment and complete this line to activate>
610 #auth_param negotiate children 20 startup=0 idle=1
611 #auth_param negotiate keep_alive on
613 #auth_param ntlm program <uncomment and complete this line to activate>
614 #auth_param ntlm children 20 startup=0 idle=1
615 #auth_param ntlm keep_alive on
617 #auth_param digest program <uncomment and complete this line>
618 #auth_param digest children 20 startup=0 idle=1
619 #auth_param digest realm Squid proxy-caching web server
620 #auth_param digest nonce_garbage_interval 5 minutes
621 #auth_param digest nonce_max_duration 30 minutes
622 #auth_param digest nonce_max_count 50
624 #auth_param basic program <uncomment and complete this line>
625 #auth_param basic children 5 startup=5 idle=1
626 #auth_param basic realm Squid proxy-caching web server
627 #auth_param basic credentialsttl 2 hours
630 NAME: authenticate_cache_garbage_interval
633 LOC: Config.authenticateGCInterval
635 The time period between garbage collection across the username cache.
636 This is a trade-off between memory utilization (long intervals - say
637 2 days) and CPU (short intervals - say 1 minute). Only change if you
641 NAME: authenticate_ttl
644 LOC: Config.authenticateTTL
646 The time a user & their credentials stay in the logged in
647 user cache since their last request. When the garbage
648 interval passes, all user credentials that have passed their
649 TTL are removed from memory.
652 NAME: authenticate_ip_ttl
654 LOC: Config.authenticateIpTTL
657 If you use proxy authentication and the 'max_user_ip' ACL,
658 this directive controls how long Squid remembers the IP
659 addresses associated with each user. Use a small value
660 (e.g., 60 seconds) if your users might change addresses
661 quickly, as is the case with dialup. You might be safe
662 using a larger value (e.g., 2 hours) in a corporate LAN
663 environment with relatively static address assignments.
668 -----------------------------------------------------------------------------
671 NAME: external_acl_type
672 TYPE: externalAclHelper
673 LOC: Config.externalAclHelperList
676 This option defines external acl classes using a helper program
677 to look up the status
679 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
683 ttl=n TTL in seconds for cached results (defaults to 3600
686 TTL for cached negative lookups (default same
689 Maximum number of acl helper processes spawned to service
690 external acl lookups of this type. (default 20)
692 Minimum number of acl helper processes to spawn during
693 startup and reconfigure to service external acl lookups
694 of this type. (default 0)
696 Number of acl helper processes to keep ahead of traffic
697 loads. Squid will spawn this many at once whenever load
698 rises above the capabilities of existing processes.
699 Up to the value of children-max. (default 1)
700 concurrency=n concurrency level per process. Only used with helpers
701 capable of processing more than one query at a time.
702 cache=n limit the result cache size, default is unbounded.
703 grace=n Percentage remaining of TTL where a refresh of a
704 cached entry should be initiated without needing to
705 wait for a new reply. (default is for no grace period)
706 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
707 ipv4 / ipv6 IP protocol used to communicate with this helper.
708 The default is to auto-detect IPv6 and use it when available.
710 FORMAT specifications
712 %LOGIN Authenticated user login name
713 %EXT_USER Username from previous external acl
714 %EXT_LOG Log details from previous external acl
715 %EXT_TAG Tag from previous external acl
716 %IDENT Ident user name
718 %SRCPORT Client source port
721 %PROTO Requested protocol
723 %PATH Requested URL path
724 %METHOD Request method
725 %MYADDR Squid interface address
726 %MYPORT Squid http_port number
727 %PATH Requested URL-path (including query-string if any)
728 %USER_CERT SSL User certificate in PEM format
729 %USER_CERTCHAIN SSL User certificate chain in PEM format
730 %USER_CERT_xx SSL User certificate subject attribute xx
731 %USER_CA_xx SSL User certificate issuer attribute xx
733 %>{Header} HTTP request header "Header"
735 HTTP request header "Hdr" list member "member"
737 HTTP request header list member using ; as
738 list separator. ; can be any non-alphanumeric
741 %<{Header} HTTP reply header "Header"
743 HTTP reply header "Hdr" list member "member"
745 HTTP reply header list member using ; as
746 list separator. ; can be any non-alphanumeric
749 %ACL The name of the ACL being tested.
750 %DATA The ACL arguments. If not used then any arguments
751 is automatically added at the end of the line
753 NOTE: this will encode the arguments as one token,
754 whereas the default will pass each separately.
756 %% The percent sign. Useful for helpers which need
757 an unchanging input format.
760 General request syntax:
762 [channel-ID] FORMAT-values [acl-values ...]
765 FORMAT-values consists of transaction details expanded with
766 whitespace separation per the config file FORMAT specification
767 using the FORMAT macros listed above.
769 acl-values consists of any string specified in the referencing
770 config 'acl ... external' line. see the "acl external" directive.
772 Request values sent to the helper are URL escaped to protect
773 each value in requests against whitespaces.
775 If using protocol=2.5 then the request sent to the helper is not
776 URL escaped to protect against whitespace.
778 NOTE: protocol=3.0 is deprecated as no longer necessary.
780 When using the concurrency= option the protocol is changed by
781 introducing a query channel tag in front of the request/response.
782 The query channel tag is a number between 0 and concurrency-1.
783 This value must be echoed back unchanged to Squid as the first part
784 of the response relating to its request.
787 The helper receives lines expanded per the above format specification
788 and for each input line returns 1 line starting with OK/ERR/BH result
789 code and optionally followed by additional keywords with more details.
792 General result syntax:
794 [channel-ID] result keyword=value ...
796 Result consists of one of the codes:
799 the ACL test produced a match.
802 the ACL test does not produce a match.
805 An internal error occurred in the helper, preventing
806 a result being identified.
808 The meaning of 'a match' is determined by your squid.conf
809 access control configuration. See the Squid wiki for details.
813 user= The users name (login)
815 password= The users password (for login= cache_peer option)
817 message= Message describing the reason for this response.
818 Available as %o in error pages.
819 Useful on (ERR and BH results).
821 tag= Apply a tag to a request. Only sets a tag once,
822 does not alter existing tags.
824 log= String to be logged in access.log. Available as
825 %ea in logformat specifications.
827 Any keywords may be sent on any response whether OK, ERR or BH.
829 All response keyword values need to be a single token with URL
830 escaping, or enclosed in double quotes (") and escaped using \ on
831 any double quotes or \ characters within the value. The wrapping
832 double quotes are removed before the value is interpreted by Squid.
833 \r and \n are also replace by CR and LF.
835 Some example key values:
839 user="J. \"Bob\" Smith"
846 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
847 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
848 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
849 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
850 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
853 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
854 DEFAULT: localhost src 127.0.0.1/32 ::1
855 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
856 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
858 Defining an Access List
860 Every access list definition must begin with an aclname and acltype,
861 followed by either type-specific arguments or a quoted filename that
864 acl aclname acltype argument ...
865 acl aclname acltype "file" ...
867 When using "file", the file should contain one item per line.
869 Some acl types supports options which changes their default behaviour.
870 The available options are:
872 -i,+i By default, regular expressions are CASE-SENSITIVE. To make them
873 case-insensitive, use the -i option. To return case-sensitive
874 use the +i option between patterns, or make a new ACL line
877 -n Disable lookups and address type conversions. If lookup or
878 conversion is required because the parameter type (IP or
879 domain name) does not match the message address type (domain
880 name or IP), then the ACL would immediately declare a mismatch
881 without any warnings or lookups.
883 -- Used to stop processing all options, in the case the first acl
884 value has '-' character as first character (for example the '-'
885 is a valid domain name)
887 Some acl types require suspending the current request in order
888 to access some external data source.
889 Those which do are marked with the tag [slow], those which
890 don't are marked as [fast].
891 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
892 for further information
894 ***** ACL TYPES AVAILABLE *****
896 acl aclname src ip-address/mask ... # clients IP address [fast]
897 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
898 acl aclname dst [-n] ip-address/mask ... # URL host's IP address [slow]
899 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
901 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
902 # The arp ACL requires the special configure option --enable-arp-acl.
903 # Furthermore, the ARP ACL code is not portable to all operating systems.
904 # It works on Linux, Solaris, Windows, FreeBSD, and some
905 # other *BSD variants.
908 # NOTE: Squid can only determine the MAC address for clients that are on
909 # the same subnet. If the client is on a different subnet,
910 # then Squid cannot find out its MAC address.
912 acl aclname srcdomain .foo.com ...
913 # reverse lookup, from client IP [slow]
914 acl aclname dstdomain [-n] .foo.com ...
915 # Destination server from URL [fast]
916 acl aclname srcdom_regex [-i] \.foo\.com ...
917 # regex matching client name [slow]
918 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
919 # regex matching server [fast]
921 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
922 # based URL is used and no match is found. The name "none" is used
923 # if the reverse lookup fails.
925 acl aclname src_as number ...
926 acl aclname dst_as number ...
928 # Except for access control, AS numbers can be used for
929 # routing of requests to specific caches. Here's an
930 # example for routing all requests for AS#1241 and only
931 # those to mycache.mydomain.net:
932 # acl asexample dst_as 1241
933 # cache_peer_access mycache.mydomain.net allow asexample
934 # cache_peer_access mycache_mydomain.net deny all
936 acl aclname peername myPeer ...
938 # match against a named cache_peer entry
939 # set unique name= on cache_peer lines for reliable use.
941 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
951 # h1:m1 must be less than h2:m2
953 acl aclname url_regex [-i] ^http:// ...
954 # regex matching on whole URL [fast]
955 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
956 # regex matching on URL login field
957 acl aclname urlpath_regex [-i] \.gif$ ...
958 # regex matching on URL path [fast]
960 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
962 acl aclname localport 3128 ... # TCP port the client connected to [fast]
963 # NP: for interception mode this is usually '80'
965 acl aclname myportname 3128 ... # http(s)_port name [fast]
967 acl aclname proto HTTP FTP ... # request protocol [fast]
969 acl aclname method GET POST ... # HTTP request method [fast]
971 acl aclname http_status 200 301 500- 400-403 ...
972 # status code in reply [fast]
974 acl aclname browser [-i] regexp ...
975 # pattern match on User-Agent header (see also req_header below) [fast]
977 acl aclname referer_regex [-i] regexp ...
978 # pattern match on Referer header [fast]
979 # Referer is highly unreliable, so use with care
981 acl aclname ident username ...
982 acl aclname ident_regex [-i] pattern ...
983 # string match on ident output [slow]
984 # use REQUIRED to accept any non-null ident.
986 acl aclname proxy_auth [-i] username ...
987 acl aclname proxy_auth_regex [-i] pattern ...
988 # perform http authentication challenge to the client and match against
989 # supplied credentials [slow]
991 # takes a list of allowed usernames.
992 # use REQUIRED to accept any valid username.
994 # Will use proxy authentication in forward-proxy scenarios, and plain
995 # http authenticaiton in reverse-proxy scenarios
997 # NOTE: when a Proxy-Authentication header is sent but it is not
998 # needed during ACL checking the username is NOT logged
1001 # NOTE: proxy_auth requires a EXTERNAL authentication program
1002 # to check username/password combinations (see
1003 # auth_param directive).
1005 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
1006 # as the browser needs to be configured for using a proxy in order
1007 # to respond to proxy authentication.
1009 acl aclname snmp_community string ...
1010 # A community string to limit access to your SNMP Agent [fast]
1013 # acl snmppublic snmp_community public
1015 acl aclname maxconn number
1016 # This will be matched when the client's IP address has
1017 # more than <number> TCP connections established. [fast]
1018 # NOTE: This only measures direct TCP links so X-Forwarded-For
1019 # indirect clients are not counted.
1021 acl aclname max_user_ip [-s] number
1022 # This will be matched when the user attempts to log in from more
1023 # than <number> different ip addresses. The authenticate_ip_ttl
1024 # parameter controls the timeout on the ip entries. [fast]
1025 # If -s is specified the limit is strict, denying browsing
1026 # from any further IP addresses until the ttl has expired. Without
1027 # -s Squid will just annoy the user by "randomly" denying requests.
1028 # (the counter is reset each time the limit is reached and a
1029 # request is denied)
1030 # NOTE: in acceleration mode or where there is mesh of child proxies,
1031 # clients may appear to come from multiple addresses if they are
1032 # going through proxy farms, so a limit of 1 may cause user problems.
1034 acl aclname random probability
1035 # Pseudo-randomly match requests. Based on the probability given.
1036 # Probability may be written as a decimal (0.333), fraction (1/3)
1037 # or ratio of matches:non-matches (3:5).
1039 acl aclname req_mime_type [-i] mime-type ...
1040 # regex match against the mime type of the request generated
1041 # by the client. Can be used to detect file upload or some
1042 # types HTTP tunneling requests [fast]
1043 # NOTE: This does NOT match the reply. You cannot use this
1044 # to match the returned file type.
1046 acl aclname req_header header-name [-i] any\.regex\.here
1047 # regex match against any of the known request headers. May be
1048 # thought of as a superset of "browser", "referer" and "mime-type"
1051 acl aclname rep_mime_type [-i] mime-type ...
1052 # regex match against the mime type of the reply received by
1053 # squid. Can be used to detect file download or some
1054 # types HTTP tunneling requests. [fast]
1055 # NOTE: This has no effect in http_access rules. It only has
1056 # effect in rules that affect the reply data stream such as
1057 # http_reply_access.
1059 acl aclname rep_header header-name [-i] any\.regex\.here
1060 # regex match against any of the known reply headers. May be
1061 # thought of as a superset of "browser", "referer" and "mime-type"
1064 acl aclname external class_name [arguments...]
1065 # external ACL lookup via a helper class defined by the
1066 # external_acl_type directive [slow]
1068 acl aclname user_cert attribute values...
1069 # match against attributes in a user SSL certificate
1070 # attribute is one of DN/C/O/CN/L/ST [fast]
1072 acl aclname ca_cert attribute values...
1073 # match against attributes a users issuing CA SSL certificate
1074 # attribute is one of DN/C/O/CN/L/ST [fast]
1076 acl aclname ext_user username ...
1077 acl aclname ext_user_regex [-i] pattern ...
1078 # string match on username returned by external acl helper [slow]
1079 # use REQUIRED to accept any non-null user name.
1081 acl aclname tag tagvalue ...
1082 # string match on tag returned by external acl helper [slow]
1084 acl aclname hier_code codename ...
1085 # string match against squid hierarchy code(s); [fast]
1086 # e.g., DIRECT, PARENT_HIT, NONE, etc.
1088 # NOTE: This has no effect in http_access rules. It only has
1089 # effect in rules that affect the reply data stream such as
1090 # http_reply_access.
1092 acl aclname note name [value ...]
1093 # match transaction annotation [fast]
1094 # Without values, matches any annotation with a given name.
1095 # With value(s), matches any annotation with a given name that
1096 # also has one of the given values.
1097 # Names and values are compared using a string equality test.
1098 # Annotation sources include note and adaptation_meta directives
1099 # as well as helper and eCAP responses.
1101 acl aclname adaptation_service service ...
1102 # Matches the name of any icap_service, ecap_service,
1103 # adaptation_service_set, or adaptation_service_chain that Squid
1104 # has used (or attempted to use) for the master transaction.
1105 # This ACL must be defined after the corresponding adaptation
1106 # service is named in squid.conf. This ACL is usable with
1107 # adaptation_meta because it starts matching immediately after
1108 # the service has been selected for adaptation.
1111 acl aclname ssl_error errorname
1112 # match against SSL certificate validation error [fast]
1114 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1117 # The following can be used as shortcuts for certificate properties:
1118 # [ssl::]certHasExpired: the "not after" field is in the past
1119 # [ssl::]certNotYetValid: the "not before" field is in the future
1120 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1121 # [ssl::]certSelfSigned: The certificate is self signed.
1122 # [ssl::]certDomainMismatch: The certificate CN domain does not
1123 # match the name the name of the host we are connecting to.
1125 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1126 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1127 # predefined ACLs, just like the 'all' ACL.
1129 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1130 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1132 acl aclname server_cert_fingerprint [-sha1] fingerprint
1133 # match against server SSL certificate fingerprint [fast]
1135 # The fingerprint is the digest of the DER encoded version
1136 # of the whole certificate. The user should use the form: XX:XX:...
1137 # Optional argument specifies the digest algorithm to use.
1138 # The SHA1 digest algorithm is the default and is currently
1139 # the only algorithm supported (-sha1).
1141 acl aclname any-of acl1 acl2 ...
1142 # match any one of the acls [fast or slow]
1143 # The first matching ACL stops further ACL evaluation.
1145 # ACLs from multiple any-of lines with the same name are ORed.
1146 # For example, A = (a1 or a2) or (a3 or a4) can be written as
1147 # acl A any-of a1 a2
1148 # acl A any-of a3 a4
1150 # This group ACL is fast if all evaluated ACLs in the group are fast
1151 # and slow otherwise.
1153 acl aclname all-of acl1 acl2 ...
1154 # match all of the acls [fast or slow]
1155 # The first mismatching ACL stops further ACL evaluation.
1157 # ACLs from multiple all-of lines with the same name are ORed.
1158 # For example, B = (b1 and b2) or (b3 and b4) can be written as
1159 # acl B all-of b1 b2
1160 # acl B all-of b3 b4
1162 # This group ACL is fast if all evaluated ACLs in the group are fast
1163 # and slow otherwise.
1166 acl macaddress arp 09:00:2b:23:45:67
1167 acl myexample dst_as 1241
1168 acl password proxy_auth REQUIRED
1169 acl fileupload req_mime_type -i ^multipart/form-data$
1170 acl javascript rep_mime_type -i ^application/x-javascript$
1174 # Recommended minimum configuration:
1177 # Example rule allowing access from your local networks.
1178 # Adapt to list your (internal) IP networks from where browsing
1180 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
1181 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
1182 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
1183 acl localnet src fc00::/7 # RFC 4193 local private network range
1184 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1186 acl SSL_ports port 443
1187 acl Safe_ports port 80 # http
1188 acl Safe_ports port 21 # ftp
1189 acl Safe_ports port 443 # https
1190 acl Safe_ports port 70 # gopher
1191 acl Safe_ports port 210 # wais
1192 acl Safe_ports port 1025-65535 # unregistered ports
1193 acl Safe_ports port 280 # http-mgmt
1194 acl Safe_ports port 488 # gss-http
1195 acl Safe_ports port 591 # filemaker
1196 acl Safe_ports port 777 # multiling http
1197 acl CONNECT method CONNECT
1201 NAME: follow_x_forwarded_for
1203 IFDEF: FOLLOW_X_FORWARDED_FOR
1204 LOC: Config.accessList.followXFF
1205 DEFAULT_IF_NONE: deny all
1206 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1208 Allowing or Denying the X-Forwarded-For header to be followed to
1209 find the original source of a request.
1211 Requests may pass through a chain of several other proxies
1212 before reaching us. The X-Forwarded-For header will contain a
1213 comma-separated list of the IP addresses in the chain, with the
1214 rightmost address being the most recent.
1216 If a request reaches us from a source that is allowed by this
1217 configuration item, then we consult the X-Forwarded-For header
1218 to see where that host received the request from. If the
1219 X-Forwarded-For header contains multiple addresses, we continue
1220 backtracking until we reach an address for which we are not allowed
1221 to follow the X-Forwarded-For header, or until we reach the first
1222 address in the list. For the purpose of ACL used in the
1223 follow_x_forwarded_for directive the src ACL type always matches
1224 the address we are testing and srcdomain matches its rDNS.
1226 The end result of this process is an IP address that we will
1227 refer to as the indirect client address. This address may
1228 be treated as the client address for access control, ICAP, delay
1229 pools and logging, depending on the acl_uses_indirect_client,
1230 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1231 log_uses_indirect_client and tproxy_uses_indirect_client options.
1233 This clause only supports fast acl types.
1234 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1236 SECURITY CONSIDERATIONS:
1238 Any host for which we follow the X-Forwarded-For header
1239 can place incorrect information in the header, and Squid
1240 will use the incorrect information as if it were the
1241 source address of the request. This may enable remote
1242 hosts to bypass any access control restrictions that are
1243 based on the client's source addresses.
1247 acl localhost src 127.0.0.1
1248 acl my_other_proxy srcdomain .proxy.example.com
1249 follow_x_forwarded_for allow localhost
1250 follow_x_forwarded_for allow my_other_proxy
1253 NAME: acl_uses_indirect_client
1256 IFDEF: FOLLOW_X_FORWARDED_FOR
1258 LOC: Config.onoff.acl_uses_indirect_client
1260 Controls whether the indirect client address
1261 (see follow_x_forwarded_for) is used instead of the
1262 direct client address in acl matching.
1264 NOTE: maxconn ACL considers direct TCP links and indirect
1265 clients will always have zero. So no match.
1268 NAME: delay_pool_uses_indirect_client
1271 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1273 LOC: Config.onoff.delay_pool_uses_indirect_client
1275 Controls whether the indirect client address
1276 (see follow_x_forwarded_for) is used instead of the
1277 direct client address in delay pools.
1280 NAME: log_uses_indirect_client
1283 IFDEF: FOLLOW_X_FORWARDED_FOR
1285 LOC: Config.onoff.log_uses_indirect_client
1287 Controls whether the indirect client address
1288 (see follow_x_forwarded_for) is used instead of the
1289 direct client address in the access log.
1292 NAME: tproxy_uses_indirect_client
1295 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1297 LOC: Config.onoff.tproxy_uses_indirect_client
1299 Controls whether the indirect client address
1300 (see follow_x_forwarded_for) is used instead of the
1301 direct client address when spoofing the outgoing client.
1303 This has no effect on requests arriving in non-tproxy
1306 SECURITY WARNING: Usage of this option is dangerous
1307 and should not be used trivially. Correct configuration
1308 of follow_x_forewarded_for with a limited set of trusted
1309 sources is required to prevent abuse of your proxy.
1312 NAME: spoof_client_ip
1314 LOC: Config.accessList.spoof_client_ip
1316 DEFAULT_DOC: Allow spoofing on all TPROXY traffic.
1318 Control client IP address spoofing of TPROXY traffic based on
1319 defined access lists.
1321 spoof_client_ip allow|deny [!]aclname ...
1323 If there are no "spoof_client_ip" lines present, the default
1324 is to "allow" spoofing of any suitable request.
1326 Note that the cache_peer "no-tproxy" option overrides this ACL.
1328 This clause supports fast acl types.
1329 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1334 LOC: Config.accessList.http
1335 DEFAULT_IF_NONE: deny all
1336 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1338 Allowing or Denying access based on defined access lists
1340 Access to the HTTP port:
1341 http_access allow|deny [!]aclname ...
1343 NOTE on default values:
1345 If there are no "access" lines present, the default is to deny
1348 If none of the "access" lines cause a match, the default is the
1349 opposite of the last line in the list. If the last line was
1350 deny, the default is allow. Conversely, if the last line
1351 is allow, the default will be deny. For these reasons, it is a
1352 good idea to have an "deny all" entry at the end of your access
1353 lists to avoid potential confusion.
1355 This clause supports both fast and slow acl types.
1356 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1361 # Recommended minimum Access Permission configuration:
1363 # Deny requests to certain unsafe ports
1364 http_access deny !Safe_ports
1366 # Deny CONNECT to other than secure SSL ports
1367 http_access deny CONNECT !SSL_ports
1369 # Only allow cachemgr access from localhost
1370 http_access allow localhost manager
1371 http_access deny manager
1373 # We strongly recommend the following be uncommented to protect innocent
1374 # web applications running on the proxy server who think the only
1375 # one who can access services on "localhost" is a local user
1376 #http_access deny to_localhost
1379 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1382 # Example rule allowing access from your local networks.
1383 # Adapt localnet in the ACL section to list your (internal) IP networks
1384 # from where browsing should be allowed
1385 http_access allow localnet
1386 http_access allow localhost
1388 # And finally deny all other access to this proxy
1389 http_access deny all
1393 NAME: adapted_http_access http_access2
1395 LOC: Config.accessList.adapted_http
1397 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1399 Allowing or Denying access based on defined access lists
1401 Essentially identical to http_access, but runs after redirectors
1402 and ICAP/eCAP adaptation. Allowing access control based on their
1405 If not set then only http_access is used.
1408 NAME: http_reply_access
1410 LOC: Config.accessList.reply
1412 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1414 Allow replies to client requests. This is complementary to http_access.
1416 http_reply_access allow|deny [!] aclname ...
1418 NOTE: if there are no access lines present, the default is to allow
1421 If none of the access lines cause a match the opposite of the
1422 last line will apply. Thus it is good practice to end the rules
1423 with an "allow all" or "deny all" entry.
1425 This clause supports both fast and slow acl types.
1426 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1431 LOC: Config.accessList.icp
1433 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1435 Allowing or Denying access to the ICP port based on defined
1438 icp_access allow|deny [!]aclname ...
1440 NOTE: The default if no icp_access lines are present is to
1441 deny all traffic. This default may cause problems with peers
1444 This clause only supports fast acl types.
1445 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1447 # Allow ICP queries from local networks only
1448 #icp_access allow localnet
1449 #icp_access deny all
1455 LOC: Config.accessList.htcp
1457 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1459 Allowing or Denying access to the HTCP port based on defined
1462 htcp_access allow|deny [!]aclname ...
1464 See also htcp_clr_access for details on access control for
1465 cache purge (CLR) HTCP messages.
1467 NOTE: The default if no htcp_access lines are present is to
1468 deny all traffic. This default may cause problems with peers
1469 using the htcp option.
1471 This clause only supports fast acl types.
1472 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1474 # Allow HTCP queries from local networks only
1475 #htcp_access allow localnet
1476 #htcp_access deny all
1479 NAME: htcp_clr_access
1482 LOC: Config.accessList.htcp_clr
1484 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1486 Allowing or Denying access to purge content using HTCP based
1487 on defined access lists.
1488 See htcp_access for details on general HTCP access control.
1490 htcp_clr_access allow|deny [!]aclname ...
1492 This clause only supports fast acl types.
1493 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1495 # Allow HTCP CLR requests from trusted peers
1496 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1497 htcp_clr_access allow htcp_clr_peer
1498 htcp_clr_access deny all
1503 LOC: Config.accessList.miss
1505 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1507 Determins whether network access is permitted when satisfying a request.
1510 to force your neighbors to use you as a sibling instead of
1513 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1514 miss_access deny !localclients
1515 miss_access allow all
1517 This means only your local clients are allowed to fetch relayed/MISS
1518 replies from the network and all other clients can only fetch cached
1521 The default for this setting allows all clients who passed the
1522 http_access rules to relay via this proxy.
1524 This clause only supports fast acl types.
1525 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1528 NAME: ident_lookup_access
1532 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1533 LOC: Ident::TheConfig.identLookup
1535 A list of ACL elements which, if matched, cause an ident
1536 (RFC 931) lookup to be performed for this request. For
1537 example, you might choose to always perform ident lookups
1538 for your main multi-user Unix boxes, but not for your Macs
1539 and PCs. By default, ident lookups are not performed for
1542 To enable ident lookups for specific client addresses, you
1543 can follow this example:
1545 acl ident_aware_hosts src 198.168.1.0/24
1546 ident_lookup_access allow ident_aware_hosts
1547 ident_lookup_access deny all
1549 Only src type ACL checks are fully supported. A srcdomain
1550 ACL might work at times, but it will not always provide
1553 This clause only supports fast acl types.
1554 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1557 NAME: reply_body_max_size
1558 COMMENT: size [acl acl...]
1561 DEFAULT_DOC: No limit is applied.
1562 LOC: Config.ReplyBodySize
1564 This option specifies the maximum size of a reply body. It can be
1565 used to prevent users from downloading very large files, such as
1566 MP3's and movies. When the reply headers are received, the
1567 reply_body_max_size lines are processed, and the first line where
1568 all (if any) listed ACLs are true is used as the maximum body size
1571 This size is checked twice. First when we get the reply headers,
1572 we check the content-length value. If the content length value exists
1573 and is larger than the allowed size, the request is denied and the
1574 user receives an error message that says "the request or reply
1575 is too large." If there is no content-length, and the reply
1576 size exceeds this limit, the client's connection is just closed
1577 and they will receive a partial reply.
1579 WARNING: downstream caches probably can not detect a partial reply
1580 if there is no content-length header, so they will cache
1581 partial responses and give them out as hits. You should NOT
1582 use this option if you have downstream caches.
1584 WARNING: A maximum size smaller than the size of squid's error messages
1585 will cause an infinite loop and crash squid. Ensure that the smallest
1586 non-zero value you use is greater that the maximum header size plus
1587 the size of your largest error page.
1589 If you set this parameter none (the default), there will be
1592 Configuration Format is:
1593 reply_body_max_size SIZE UNITS [acl ...]
1595 reply_body_max_size 10 MB
1601 -----------------------------------------------------------------------------
1604 NAME: http_port ascii_port
1607 LOC: Config.Sockaddr.http
1609 Usage: port [mode] [options]
1610 hostname:port [mode] [options]
1611 1.2.3.4:port [mode] [options]
1613 The socket addresses where Squid will listen for HTTP client
1614 requests. You may specify multiple socket addresses.
1615 There are three forms: port alone, hostname with port, and
1616 IP address with port. If you specify a hostname or IP
1617 address, Squid binds the socket to that specific
1618 address. Most likely, you do not need to bind to a specific
1619 address, so you can use the port number alone.
1621 If you are running Squid in accelerator mode, you
1622 probably want to listen on port 80 also, or instead.
1624 The -a command line option may be used to specify additional
1625 port(s) where Squid listens for proxy request. Such ports will
1626 be plain proxy ports with no options.
1628 You may specify multiple socket addresses on multiple lines.
1632 intercept Support for IP-Layer interception of
1633 outgoing requests without browser settings.
1634 NP: disables authentication and IPv6 on the port.
1636 tproxy Support Linux TPROXY for spoofing outgoing
1637 connections using the client IP address.
1638 NP: disables authentication and maybe IPv6 on the port.
1640 accel Accelerator / reverse proxy mode
1642 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1643 establish secure connection with the client and with
1644 the server, decrypt HTTPS messages as they pass through
1645 Squid, and treat them as unencrypted HTTP messages,
1646 becoming the man-in-the-middle.
1648 The ssl_bump option is required to fully enable
1649 bumping of CONNECT requests.
1651 Omitting the mode flag causes default forward proxy mode to be used.
1654 Accelerator Mode Options:
1656 defaultsite=domainname
1657 What to use for the Host: header if it is not present
1658 in a request. Determines what site (not origin server)
1659 accelerators should consider the default.
1661 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1663 protocol= Protocol to reconstruct accelerated and intercepted
1664 requests with. Defaults to HTTP/1.1 for http_port and
1665 HTTPS/1.1 for https_port.
1666 When an unsupported value is configured Squid will
1667 produce a FATAL error.
1668 Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
1670 vport Virtual host port support. Using the http_port number
1671 instead of the port passed on Host: headers.
1673 vport=NN Virtual host port support. Using the specified port
1674 number instead of the port passed on Host: headers.
1677 Act as if this Squid is the origin server.
1678 This currently means generate new Date: and Expires:
1679 headers on HIT instead of adding Age:.
1681 ignore-cc Ignore request Cache-Control headers.
1683 WARNING: This option violates HTTP specifications if
1684 used in non-accelerator setups.
1686 allow-direct Allow direct forwarding in accelerator mode. Normally
1687 accelerated requests are denied direct forwarding as if
1688 never_direct was used.
1690 WARNING: this option opens accelerator mode to security
1691 vulnerabilities usually only affecting in interception
1692 mode. Make sure to protect forwarding with suitable
1693 http_access rules when using this.
1696 SSL Bump Mode Options:
1697 In addition to these options ssl-bump requires TLS/SSL options.
1699 generate-host-certificates[=<on|off>]
1700 Dynamically create SSL server certificates for the
1701 destination hosts of bumped CONNECT requests.When
1702 enabled, the cert and key options are used to sign
1703 generated certificates. Otherwise generated
1704 certificate will be selfsigned.
1705 If there is a CA certificate lifetime of the generated
1706 certificate equals lifetime of the CA certificate. If
1707 generated certificate is selfsigned lifetime is three
1709 This option is enabled by default when ssl-bump is used.
1710 See the ssl-bump option above for more information.
1712 dynamic_cert_mem_cache_size=SIZE
1713 Approximate total RAM size spent on cached generated
1714 certificates. If set to zero, caching is disabled. The
1715 default value is 4MB.
1719 cert= Path to SSL certificate (PEM format).
1721 key= Path to SSL private key file (PEM format)
1722 if not specified, the certificate file is
1723 assumed to be a combined certificate and
1726 version= The version of SSL/TLS supported
1727 1 automatic (default)
1734 cipher= Colon separated list of supported ciphers.
1735 NOTE: some ciphers such as EDH ciphers depend on
1736 additional settings. If those settings are
1737 omitted the ciphers may be silently ignored
1738 by the OpenSSL library.
1740 options= Various SSL implementation options. The most important
1742 NO_SSLv2 Disallow the use of SSLv2
1743 NO_SSLv3 Disallow the use of SSLv3
1744 NO_TLSv1 Disallow the use of TLSv1.0
1745 NO_TLSv1_1 Disallow the use of TLSv1.1
1746 NO_TLSv1_2 Disallow the use of TLSv1.2
1747 SINGLE_DH_USE Always create a new key when using
1748 temporary/ephemeral DH key exchanges
1749 ALL Enable various bug workarounds
1750 suggested as "harmless" by OpenSSL
1751 Be warned that this reduces SSL/TLS
1752 strength to some attacks.
1753 See OpenSSL SSL_CTX_set_options documentation for a
1754 complete list of options.
1756 clientca= File containing the list of CAs to use when
1757 requesting a client certificate.
1759 cafile= File containing additional CA certificates to
1760 use when verifying client certificates. If unset
1761 clientca will be used.
1763 capath= Directory containing additional CA certificates
1764 and CRL lists to use when verifying client certificates.
1766 crlfile= File of additional CRL lists to use when verifying
1767 the client certificate, in addition to CRLs stored in
1768 the capath. Implies VERIFY_CRL flag below.
1770 dhparams= File containing DH parameters for temporary/ephemeral
1771 DH key exchanges. See OpenSSL documentation for details
1772 on how to create this file.
1773 WARNING: EDH ciphers will be silently disabled if this
1776 sslflags= Various flags modifying the use of SSL:
1778 Don't request client certificates
1779 immediately, but wait until acl processing
1780 requires a certificate (not yet implemented).
1782 Don't use the default CA lists built in
1785 Don't allow for session reuse. Each connection
1786 will result in a new SSL session.
1788 Verify CRL lists when accepting client
1791 Verify CRL lists for all certificates in the
1792 client certificate chain.
1794 sslcontext= SSL session ID context identifier.
1798 connection-auth[=on|off]
1799 use connection-auth=off to tell Squid to prevent
1800 forwarding Microsoft connection oriented authentication
1801 (NTLM, Negotiate and Kerberos)
1803 disable-pmtu-discovery=
1804 Control Path-MTU discovery usage:
1805 off lets OS decide on what to do (default).
1806 transparent disable PMTU discovery when transparent
1808 always disable always PMTU discovery.
1810 In many setups of transparently intercepting proxies
1811 Path-MTU discovery can not work on traffic towards the
1812 clients. This is the case when the intercepting device
1813 does not fully track connections and fails to forward
1814 ICMP must fragment messages to the cache server. If you
1815 have such setup and experience that certain clients
1816 sporadically hang or never complete requests set
1817 disable-pmtu-discovery option to 'transparent'.
1819 name= Specifies a internal name for the port. Defaults to
1820 the port specification (port or addr:port)
1822 tcpkeepalive[=idle,interval,timeout]
1823 Enable TCP keepalive probes of idle connections.
1824 In seconds; idle is the initial time before TCP starts
1825 probing the connection, interval how often to probe, and
1826 timeout the time before giving up.
1828 If you run Squid on a dual-homed machine with an internal
1829 and an external interface we recommend you to specify the
1830 internal address:port in http_port. This way Squid will only be
1831 visible on the internal address.
1835 # Squid normally listens to port 3128
1836 http_port @DEFAULT_HTTP_PORT@
1844 LOC: Config.Sockaddr.https
1846 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1848 The socket address where Squid will listen for client requests made
1849 over TLS or SSL connections. Commonly referred to as HTTPS.
1851 This is most useful for situations where you are running squid in
1852 accelerator mode and you want to do the SSL work at the accelerator level.
1854 You may specify multiple socket addresses on multiple lines,
1855 each with their own SSL certificate and/or options.
1859 accel Accelerator / reverse proxy mode
1861 intercept Support for IP-Layer interception of
1862 outgoing requests without browser settings.
1863 NP: disables authentication and IPv6 on the port.
1865 tproxy Support Linux TPROXY for spoofing outgoing
1866 connections using the client IP address.
1867 NP: disables authentication and maybe IPv6 on the port.
1869 ssl-bump For each intercepted connection allowed by ssl_bump
1870 ACLs, establish a secure connection with the client and with
1871 the server, decrypt HTTPS messages as they pass through
1872 Squid, and treat them as unencrypted HTTP messages,
1873 becoming the man-in-the-middle.
1875 An "ssl_bump server-first" match is required to
1876 fully enable bumping of intercepted SSL connections.
1878 Requires tproxy or intercept.
1880 Omitting the mode flag causes default forward proxy mode to be used.
1883 See http_port for a list of generic options
1888 cert= Path to SSL certificate (PEM format).
1890 key= Path to SSL private key file (PEM format)
1891 if not specified, the certificate file is
1892 assumed to be a combined certificate and
1895 version= The version of SSL/TLS supported
1896 1 automatic (default)
1901 cipher= Colon separated list of supported ciphers.
1903 options= Various SSL engine options. The most important
1905 NO_SSLv2 Disallow the use of SSLv2
1906 NO_SSLv3 Disallow the use of SSLv3
1907 NO_TLSv1 Disallow the use of TLSv1
1908 SINGLE_DH_USE Always create a new key when using
1909 temporary/ephemeral DH key exchanges
1910 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1911 documentation for a complete list of options.
1913 clientca= File containing the list of CAs to use when
1914 requesting a client certificate.
1916 cafile= File containing additional CA certificates to
1917 use when verifying client certificates. If unset
1918 clientca will be used.
1920 capath= Directory containing additional CA certificates
1921 and CRL lists to use when verifying client certificates.
1923 crlfile= File of additional CRL lists to use when verifying
1924 the client certificate, in addition to CRLs stored in
1925 the capath. Implies VERIFY_CRL flag below.
1927 dhparams= File containing DH parameters for temporary/ephemeral
1930 sslflags= Various flags modifying the use of SSL:
1932 Don't request client certificates
1933 immediately, but wait until acl processing
1934 requires a certificate (not yet implemented).
1936 Don't use the default CA lists built in
1939 Don't allow for session reuse. Each connection
1940 will result in a new SSL session.
1942 Verify CRL lists when accepting client
1945 Verify CRL lists for all certificates in the
1946 client certificate chain.
1948 sslcontext= SSL session ID context identifier.
1950 generate-host-certificates[=<on|off>]
1951 Dynamically create SSL server certificates for the
1952 destination hosts of bumped SSL requests.When
1953 enabled, the cert and key options are used to sign
1954 generated certificates. Otherwise generated
1955 certificate will be selfsigned.
1956 If there is CA certificate life time of generated
1957 certificate equals lifetime of CA certificate. If
1958 generated certificate is selfsigned lifetime is three
1960 This option is enabled by default when SslBump is used.
1961 See the sslBump option above for more information.
1963 dynamic_cert_mem_cache_size=SIZE
1964 Approximate total RAM size spent on cached generated
1965 certificates. If set to zero, caching is disabled. The
1966 default value is 4MB.
1968 See http_port for a list of available options.
1974 LOC: Config.Sockaddr.ftp
1976 Usage: [ip:]port [options]
1979 ftp-track-dirs=on|off
1980 Enables tracking of FTP directories by injecting extra
1981 PWD commands and adjusting Request-URI (in wrapping HTTP
1982 requests) to reflect the current FTP server directory.
1983 Disabled by default.
1985 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1988 LOC: Ip::Qos::TheConfig.tosToServer
1990 Allows you to select a TOS/Diffserv value for packets outgoing
1991 on the server side, based on an ACL.
1993 tcp_outgoing_tos ds-field [!]aclname ...
1995 Example where normal_service_net uses the TOS value 0x00
1996 and good_service_net uses 0x20
1998 acl normal_service_net src 10.0.0.0/24
1999 acl good_service_net src 10.0.1.0/24
2000 tcp_outgoing_tos 0x00 normal_service_net
2001 tcp_outgoing_tos 0x20 good_service_net
2003 TOS/DSCP values really only have local significance - so you should
2004 know what you're specifying. For more information, see RFC2474,
2005 RFC2475, and RFC3260.
2007 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2008 "default" to use whatever default your host has. Note that in
2009 practice often only multiples of 4 is usable as the two rightmost bits
2010 have been redefined for use by ECN (RFC 3168 section 23.1).
2012 Processing proceeds in the order specified, and stops at first fully
2016 NAME: clientside_tos
2019 LOC: Ip::Qos::TheConfig.tosToClient
2021 Allows you to select a TOS/Diffserv value for packets being transmitted
2022 on the client-side, based on an ACL.
2024 clientside_tos ds-field [!]aclname ...
2026 Example where normal_service_net uses the TOS value 0x00
2027 and good_service_net uses 0x20
2029 acl normal_service_net src 10.0.0.0/24
2030 acl good_service_net src 10.0.1.0/24
2031 clientside_tos 0x00 normal_service_net
2032 clientside_tos 0x20 good_service_net
2034 Note: This feature is incompatible with qos_flows. Any TOS values set here
2035 will be overwritten by TOS values in qos_flows.
2038 NAME: tcp_outgoing_mark
2040 IFDEF: SO_MARK&&USE_LIBCAP
2042 LOC: Ip::Qos::TheConfig.nfmarkToServer
2044 Allows you to apply a Netfilter mark value to outgoing packets
2045 on the server side, based on an ACL.
2047 tcp_outgoing_mark mark-value [!]aclname ...
2049 Example where normal_service_net uses the mark value 0x00
2050 and good_service_net uses 0x20
2052 acl normal_service_net src 10.0.0.0/24
2053 acl good_service_net src 10.0.1.0/24
2054 tcp_outgoing_mark 0x00 normal_service_net
2055 tcp_outgoing_mark 0x20 good_service_net
2058 NAME: clientside_mark
2060 IFDEF: SO_MARK&&USE_LIBCAP
2062 LOC: Ip::Qos::TheConfig.nfmarkToClient
2064 Allows you to apply a Netfilter mark value to packets being transmitted
2065 on the client-side, based on an ACL.
2067 clientside_mark mark-value [!]aclname ...
2069 Example where normal_service_net uses the mark value 0x00
2070 and good_service_net uses 0x20
2072 acl normal_service_net src 10.0.0.0/24
2073 acl good_service_net src 10.0.1.0/24
2074 clientside_mark 0x00 normal_service_net
2075 clientside_mark 0x20 good_service_net
2077 Note: This feature is incompatible with qos_flows. Any mark values set here
2078 will be overwritten by mark values in qos_flows.
2085 LOC: Ip::Qos::TheConfig
2087 Allows you to select a TOS/DSCP value to mark outgoing
2088 connections to the client, based on where the reply was sourced.
2089 For platforms using netfilter, allows you to set a netfilter mark
2090 value instead of, or in addition to, a TOS value.
2092 By default this functionality is disabled. To enable it with the default
2093 settings simply use "qos_flows mark" or "qos_flows tos". Default
2094 settings will result in the netfilter mark or TOS value being copied
2095 from the upstream connection to the client. Note that it is the connection
2096 CONNMARK value not the packet MARK value that is copied.
2098 It is not currently possible to copy the mark or TOS value from the
2099 client to the upstream connection request.
2101 TOS values really only have local significance - so you should
2102 know what you're specifying. For more information, see RFC2474,
2103 RFC2475, and RFC3260.
2105 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
2106 in practice often only multiples of 4 is usable as the two rightmost bits
2107 have been redefined for use by ECN (RFC 3168 section 23.1).
2109 Mark values can be any unsigned 32-bit integer value.
2111 This setting is configured by setting the following values:
2113 tos|mark Whether to set TOS or netfilter mark values
2115 local-hit=0xFF Value to mark local cache hits.
2117 sibling-hit=0xFF Value to mark hits from sibling peers.
2119 parent-hit=0xFF Value to mark hits from parent peers.
2121 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2122 over the preserve-miss feature (see below), unless
2123 mask is specified, in which case only the bits
2124 specified in the mask are written.
2126 The TOS variant of the following features are only possible on Linux
2127 and require your kernel to be patched with the TOS preserving ZPH
2128 patch, available from http://zph.bratcheda.org
2129 No patch is needed to preserve the netfilter mark, which will work
2130 with all variants of netfilter.
2132 disable-preserve-miss
2133 This option disables the preservation of the TOS or netfilter
2134 mark. By default, the existing TOS or netfilter mark value of
2135 the response coming from the remote server will be retained
2136 and masked with miss-mark.
2137 NOTE: in the case of a netfilter mark, the mark must be set on
2138 the connection (using the CONNMARK target) not on the packet
2142 Allows you to mask certain bits in the TOS or mark value
2143 received from the remote server, before copying the value to
2144 the TOS sent towards clients.
2145 Default for tos: 0xFF (TOS from server is not changed).
2146 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2148 All of these features require the --enable-zph-qos compilation flag
2149 (enabled by default). Netfilter marking also requires the
2150 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2151 libcap 2.09+ (--with-libcap).
2155 NAME: tcp_outgoing_address
2158 DEFAULT_DOC: Address selection is performed by the operating system.
2159 LOC: Config.accessList.outgoing_address
2161 Allows you to map requests to different outgoing IP addresses
2162 based on the username or source address of the user making
2165 tcp_outgoing_address ipaddr [[!]aclname] ...
2168 Forwarding clients with dedicated IPs for certain subnets.
2170 acl normal_service_net src 10.0.0.0/24
2171 acl good_service_net src 10.0.2.0/24
2173 tcp_outgoing_address 2001:db8::c001 good_service_net
2174 tcp_outgoing_address 10.1.0.2 good_service_net
2176 tcp_outgoing_address 2001:db8::beef normal_service_net
2177 tcp_outgoing_address 10.1.0.1 normal_service_net
2179 tcp_outgoing_address 2001:db8::1
2180 tcp_outgoing_address 10.1.0.3
2182 Processing proceeds in the order specified, and stops at first fully
2185 Squid will add an implicit IP version test to each line.
2186 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2187 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2190 NOTE: The use of this directive using client dependent ACLs is
2191 incompatible with the use of server side persistent connections. To
2192 ensure correct results it is best to set server_persistent_connections
2193 to off when using this directive in such configurations.
2195 NOTE: The use of this directive to set a local IP on outgoing TCP links
2196 is incompatible with using TPROXY to set client IP out outbound TCP links.
2197 When needing to contact peers use the no-tproxy cache_peer option and the
2198 client_dst_passthru directive re-enable normal forwarding such as this.
2202 NAME: host_verify_strict
2205 LOC: Config.onoff.hostStrictVerify
2207 Regardless of this option setting, when dealing with intercepted
2208 traffic, Squid always verifies that the destination IP address matches
2209 the Host header domain or IP (called 'authority form URL').
2211 This enforcement is performed to satisfy a MUST-level requirement in
2212 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2213 authority of the origin server or gateway given by the original URL".
2216 Squid always responds with an HTTP 409 (Conflict) error
2217 page and logs a security warning if there is no match.
2219 Squid verifies that the destination IP address matches
2220 the Host header for forward-proxy and reverse-proxy traffic
2221 as well. For those traffic types, Squid also enables the
2222 following checks, comparing the corresponding Host header
2223 and Request-URI components:
2225 * The host names (domain or IP) must be identical,
2226 but valueless or missing Host header disables all checks.
2227 For the two host names to match, both must be either IP
2230 * Port numbers must be identical, but if a port is missing
2231 the scheme-default port is assumed.
2234 When set to OFF (the default):
2235 Squid allows suspicious requests to continue but logs a
2236 security warning and blocks caching of the response.
2238 * Forward-proxy traffic is not checked at all.
2240 * Reverse-proxy traffic is not checked at all.
2242 * Intercepted traffic which passes verification is handled
2243 according to client_dst_passthru.
2245 * Intercepted requests which fail verification are sent
2246 to the client original destination instead of DIRECT.
2247 This overrides 'client_dst_passthru off'.
2249 For now suspicious intercepted CONNECT requests are always
2250 responded to with an HTTP 409 (Conflict) error page.
2255 As described in CVE-2009-0801 when the Host: header alone is used
2256 to determine the destination of a request it becomes trivial for
2257 malicious scripts on remote websites to bypass browser same-origin
2258 security policy and sandboxing protections.
2260 The cause of this is that such applets are allowed to perform their
2261 own HTTP stack, in which case the same-origin policy of the browser
2262 sandbox only verifies that the applet tries to contact the same IP
2263 as from where it was loaded at the IP level. The Host: header may
2264 be different from the connected IP and approved origin.
2268 NAME: client_dst_passthru
2271 LOC: Config.onoff.client_dst_passthru
2273 With NAT or TPROXY intercepted traffic Squid may pass the request
2274 directly to the original client destination IP or seek a faster
2275 source using the HTTP Host header.
2277 Using Host to locate alternative servers can provide faster
2278 connectivity with a range of failure recovery options.
2279 But can also lead to connectivity trouble when the client and
2280 server are attempting stateful interactions unaware of the proxy.
2282 This option (on by default) prevents alternative DNS entries being
2283 located to send intercepted traffic DIRECT to an origin server.
2284 The clients original destination IP and port will be used instead.
2286 Regardless of this option setting, when dealing with intercepted
2287 traffic Squid will verify the Host: header and any traffic which
2288 fails Host verification will be treated as if this option were ON.
2290 see host_verify_strict for details on the verification process.
2295 -----------------------------------------------------------------------------
2298 NAME: ssl_unclean_shutdown
2302 LOC: Config.SSL.unclean_shutdown
2304 Some browsers (especially MSIE) bugs out on SSL shutdown
2311 LOC: Config.SSL.ssl_engine
2314 The OpenSSL engine to use. You will need to set this if you
2315 would like to use hardware SSL acceleration for example.
2318 NAME: sslproxy_client_certificate
2321 LOC: Config.ssl_client.cert
2324 Client SSL Certificate to use when proxying https:// URLs
2327 NAME: sslproxy_client_key
2330 LOC: Config.ssl_client.key
2333 Client SSL Key to use when proxying https:// URLs
2336 NAME: sslproxy_version
2339 DEFAULT_DOC: automatic SSL/TLS version negotiation
2340 LOC: Config.ssl_client.version
2343 SSL version level to use when proxying https:// URLs
2345 The versions of SSL/TLS supported:
2347 1 automatic (default)
2355 NAME: sslproxy_options
2358 LOC: Config.ssl_client.options
2361 SSL implementation options to use when proxying https:// URLs
2363 The most important being:
2365 NO_SSLv2 Disallow the use of SSLv2
2366 NO_SSLv3 Disallow the use of SSLv3
2367 NO_TLSv1 Disallow the use of TLSv1.0
2368 NO_TLSv1_1 Disallow the use of TLSv1.1
2369 NO_TLSv1_2 Disallow the use of TLSv1.2
2371 Always create a new key when using temporary/ephemeral
2374 Disable use of RFC5077 session tickets. Some servers
2375 may have problems understanding the TLS extension due
2376 to ambiguous specification in RFC4507.
2377 ALL Enable various bug workarounds suggested as "harmless"
2378 by OpenSSL. Be warned that this may reduce SSL/TLS
2379 strength to some attacks.
2381 See the OpenSSL SSL_CTX_set_options documentation for a
2382 complete list of possible options.
2385 NAME: sslproxy_cipher
2388 LOC: Config.ssl_client.cipher
2391 SSL cipher list to use when proxying https:// URLs
2393 Colon separated list of supported ciphers.
2396 NAME: sslproxy_cafile
2399 LOC: Config.ssl_client.cafile
2402 file containing CA certificates to use when verifying server
2403 certificates while proxying https:// URLs
2406 NAME: sslproxy_capath
2409 LOC: Config.ssl_client.capath
2412 directory containing CA certificates to use when verifying
2413 server certificates while proxying https:// URLs
2416 NAME: sslproxy_session_ttl
2419 LOC: Config.SSL.session_ttl
2422 Sets the timeout value for SSL sessions
2425 NAME: sslproxy_session_cache_size
2428 LOC: Config.SSL.sessionCacheSize
2431 Sets the cache size to use for ssl session
2436 TYPE: sslproxy_ssl_bump
2437 LOC: Config.accessList.ssl_bump
2438 DEFAULT_DOC: Does not bump unless rules are present in squid.conf
2441 This option is consulted when a CONNECT request is received on
2442 an http_port (or a new connection is intercepted at an
2443 https_port), provided that port was configured with an ssl-bump
2444 flag. The subsequent data on the connection is either treated as
2445 HTTPS and decrypted OR tunneled at TCP level without decryption,
2446 depending on the first bumping "mode" which ACLs match.
2448 ssl_bump <mode> [!]acl ...
2450 The following bumping modes are supported:
2453 Allow bumping of the connection. Establish a secure connection
2454 with the client first, then connect to the server. This old mode
2455 does not allow Squid to mimic server SSL certificate and does
2456 not work with intercepted SSL connections.
2459 Allow bumping of the connection. Establish a secure connection
2460 with the server first, then establish a secure connection with
2461 the client, using a mimicked server certificate. Works with both
2462 CONNECT requests and intercepted SSL connections.
2465 Become a TCP tunnel without decoding the connection.
2466 Works with both CONNECT requests and intercepted SSL
2467 connections. This is the default behavior when no
2468 ssl_bump option is given or no ssl_bump ACLs match.
2470 By default, no connections are bumped.
2472 The first matching ssl_bump option wins. If no ACLs match, the
2473 connection is not bumped. Unlike most allow/deny ACL lists, ssl_bump
2474 does not have an implicit "negate the last given option" rule. You
2475 must make that rule explicit if you convert old ssl_bump allow/deny
2476 rules that rely on such an implicit rule.
2478 This clause supports both fast and slow acl types.
2479 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2481 See also: http_port ssl-bump, https_port ssl-bump
2484 # Example: Bump all requests except those originating from
2485 # localhost or those going to example.com.
2487 acl broken_sites dstdomain .example.com
2488 ssl_bump none localhost
2489 ssl_bump none broken_sites
2490 ssl_bump server-first all
2493 NAME: sslproxy_flags
2496 LOC: Config.ssl_client.flags
2499 Various flags modifying the use of SSL while proxying https:// URLs:
2500 DONT_VERIFY_PEER Accept certificates that fail verification.
2501 For refined control, see sslproxy_cert_error.
2502 NO_DEFAULT_CA Don't use the default CA list built in
2506 NAME: sslproxy_cert_error
2509 DEFAULT_DOC: Server certificate errors terminate the transaction.
2510 LOC: Config.ssl_client.cert_error
2513 Use this ACL to bypass server certificate validation errors.
2515 For example, the following lines will bypass all validation errors
2516 when talking to servers for example.com. All other
2517 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2519 acl BrokenButTrustedServers dstdomain example.com
2520 sslproxy_cert_error allow BrokenButTrustedServers
2521 sslproxy_cert_error deny all
2523 This clause only supports fast acl types.
2524 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2525 Using slow acl types may result in server crashes
2527 Without this option, all server certificate validation errors
2528 terminate the transaction to protect Squid and the client.
2530 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2531 but should not happen unless your OpenSSL library is buggy.
2534 Bypassing validation errors is dangerous because an
2535 error usually implies that the server cannot be trusted
2536 and the connection may be insecure.
2538 See also: sslproxy_flags and DONT_VERIFY_PEER.
2541 NAME: sslproxy_cert_sign
2544 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2545 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2546 POSTSCRIPTUM: signTrusted all
2547 TYPE: sslproxy_cert_sign
2548 LOC: Config.ssl_client.cert_sign
2551 sslproxy_cert_sign <signing algorithm> acl ...
2553 The following certificate signing algorithms are supported:
2556 Sign using the configured CA certificate which is usually
2557 placed in and trusted by end-user browsers. This is the
2558 default for trusted origin server certificates.
2561 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2562 This is the default for untrusted origin server certificates
2563 that are not self-signed (see ssl::certUntrusted).
2566 Sign using a self-signed certificate with the right CN to
2567 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2568 browser. This is the default for self-signed origin server
2569 certificates (see ssl::certSelfSigned).
2571 This clause only supports fast acl types.
2573 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2574 signing algorithm to generate the certificate and ignores all
2575 subsequent sslproxy_cert_sign options (the first match wins). If no
2576 acl(s) match, the default signing algorithm is determined by errors
2577 detected when obtaining and validating the origin server certificate.
2579 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2580 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2581 CONNECT request that carries a domain name. In all other cases (CONNECT
2582 to an IP address or an intercepted SSL connection), Squid cannot detect
2583 the domain mismatch at certificate generation time when
2584 bump-server-first is used.
2587 NAME: sslproxy_cert_adapt
2590 TYPE: sslproxy_cert_adapt
2591 LOC: Config.ssl_client.cert_adapt
2594 sslproxy_cert_adapt <adaptation algorithm> acl ...
2596 The following certificate adaptation algorithms are supported:
2599 Sets the "Not After" property to the "Not After" property of
2600 the CA certificate used to sign generated certificates.
2603 Sets the "Not Before" property to the "Not Before" property of
2604 the CA certificate used to sign generated certificates.
2606 setCommonName or setCommonName{CN}
2607 Sets Subject.CN property to the host name specified as a
2608 CN parameter or, if no explicit CN parameter was specified,
2609 extracted from the CONNECT request. It is a misconfiguration
2610 to use setCommonName without an explicit parameter for
2611 intercepted or tproxied SSL connections.
2613 This clause only supports fast acl types.
2615 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2616 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2617 corresponding adaptation algorithm to generate the certificate and
2618 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2619 group (i.e., the first match wins within each algorithm group). If no
2620 acl(s) match, the default mimicking action takes place.
2622 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2623 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2624 CONNECT request that carries a domain name. In all other cases (CONNECT
2625 to an IP address or an intercepted SSL connection), Squid cannot detect
2626 the domain mismatch at certificate generation time when
2627 bump-server-first is used.
2630 NAME: sslpassword_program
2633 LOC: Config.Program.ssl_password
2636 Specify a program used for entering SSL key passphrases
2637 when using encrypted SSL certificate keys. If not specified
2638 keys must either be unencrypted, or Squid started with the -N
2639 option to allow it to query interactively for the passphrase.
2641 The key file name is given as argument to the program allowing
2642 selection of the right password if you have multiple encrypted
2647 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2648 -----------------------------------------------------------------------------
2651 NAME: sslcrtd_program
2654 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2655 LOC: Ssl::TheConfig.ssl_crtd
2657 Specify the location and options of the executable for ssl_crtd process.
2658 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2659 For more information use:
2660 @DEFAULT_SSL_CRTD@ -h
2663 NAME: sslcrtd_children
2664 TYPE: HelperChildConfig
2666 DEFAULT: 32 startup=5 idle=1
2667 LOC: Ssl::TheConfig.ssl_crtdChildren
2669 The maximum number of processes spawn to service ssl server.
2670 The maximum this may be safely set to is 32.
2672 The startup= and idle= options allow some measure of skew in your
2677 Sets the minimum number of processes to spawn when Squid
2678 starts or reconfigures. When set to zero the first request will
2679 cause spawning of the first child process to handle it.
2681 Starting too few children temporary slows Squid under load while it
2682 tries to spawn enough additional processes to cope with traffic.
2686 Sets a minimum of how many processes Squid is to try and keep available
2687 at all times. When traffic begins to rise above what the existing
2688 processes can handle this many more will be spawned up to the maximum
2689 configured. A minimum setting of 1 is required.
2691 You must have at least one ssl_crtd process.
2694 NAME: sslcrtvalidator_program
2698 LOC: Ssl::TheConfig.ssl_crt_validator
2700 Specify the location and options of the executable for ssl_crt_validator
2703 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
2706 ttl=n TTL in seconds for cached results. The default is 60 secs
2707 cache=n limit the result cache size. The default value is 2048
2710 NAME: sslcrtvalidator_children
2711 TYPE: HelperChildConfig
2713 DEFAULT: 32 startup=5 idle=1 concurrency=1
2714 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2716 The maximum number of processes spawn to service SSL server.
2717 The maximum this may be safely set to is 32.
2719 The startup= and idle= options allow some measure of skew in your
2724 Sets the minimum number of processes to spawn when Squid
2725 starts or reconfigures. When set to zero the first request will
2726 cause spawning of the first child process to handle it.
2728 Starting too few children temporary slows Squid under load while it
2729 tries to spawn enough additional processes to cope with traffic.
2733 Sets a minimum of how many processes Squid is to try and keep available
2734 at all times. When traffic begins to rise above what the existing
2735 processes can handle this many more will be spawned up to the maximum
2736 configured. A minimum setting of 1 is required.
2740 The number of requests each certificate validator helper can handle in
2741 parallel. A value of 0 indicates the certficate validator does not
2742 support concurrency. Defaults to 1.
2744 When this directive is set to a value >= 1 then the protocol
2745 used to communicate with the helper is modified to include
2746 a request ID in front of the request/response. The request
2747 ID from the request must be echoed back with the response
2750 You must have at least one ssl_crt_validator process.
2754 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2755 -----------------------------------------------------------------------------
2763 To specify other caches in a hierarchy, use the format:
2765 cache_peer hostname type http-port icp-port [options]
2770 # hostname type port port options
2771 # -------------------- -------- ----- ----- -----------
2772 cache_peer parent.foo.net parent 3128 3130 default
2773 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2774 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2775 cache_peer example.com parent 80 0 default
2776 cache_peer cdn.example.com sibling 3128 0
2778 type: either 'parent', 'sibling', or 'multicast'.
2780 proxy-port: The port number where the peer accept HTTP requests.
2781 For other Squid proxies this is usually 3128
2782 For web servers this is usually 80
2784 icp-port: Used for querying neighbor caches about objects.
2785 Set to 0 if the peer does not support ICP or HTCP.
2786 See ICP and HTCP options below for additional details.
2789 ==== ICP OPTIONS ====
2791 You MUST also set icp_port and icp_access explicitly when using these options.
2792 The defaults will prevent peer traffic using ICP.
2795 no-query Disable ICP queries to this neighbor.
2798 Indicates the named peer is a member of a multicast group.
2799 ICP queries will not be sent directly to the peer, but ICP
2800 replies will be accepted from it.
2802 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2803 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2806 To only send ICP queries to this neighbor infrequently.
2807 This is used to keep the neighbor round trip time updated
2808 and is usually used in conjunction with weighted-round-robin.
2811 ==== HTCP OPTIONS ====
2813 You MUST also set htcp_port and htcp_access explicitly when using these options.
2814 The defaults will prevent peer traffic using HTCP.
2817 htcp Send HTCP, instead of ICP, queries to the neighbor.
2818 You probably also want to set the "icp-port" to 4827
2819 instead of 3130. This directive accepts a comma separated
2820 list of options described below.
2822 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2824 htcp=no-clr Send HTCP to the neighbor but without
2825 sending any CLR requests. This cannot be used with
2828 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2829 This cannot be used with no-clr.
2832 Send HTCP to the neighbor including CLRs but only when
2833 they do not result from PURGE requests.
2836 Forward any HTCP CLR requests this proxy receives to the peer.
2839 ==== PEER SELECTION METHODS ====
2841 The default peer selection method is ICP, with the first responding peer
2842 being used as source. These options can be used for better load balancing.
2845 default This is a parent cache which can be used as a "last-resort"
2846 if a peer cannot be located by any of the peer-selection methods.
2847 If specified more than once, only the first is used.
2849 round-robin Load-Balance parents which should be used in a round-robin
2850 fashion in the absence of any ICP queries.
2851 weight=N can be used to add bias.
2853 weighted-round-robin
2854 Load-Balance parents which should be used in a round-robin
2855 fashion with the frequency of each parent being based on the
2856 round trip time. Closer parents are used more often.
2857 Usually used for background-ping parents.
2858 weight=N can be used to add bias.
2860 carp Load-Balance parents which should be used as a CARP array.
2861 The requests will be distributed among the parents based on the
2862 CARP load balancing hash function based on their weight.
2864 userhash Load-balance parents based on the client proxy_auth or ident username.
2866 sourcehash Load-balance parents based on the client source IP.
2869 To be used only for cache peers of type "multicast".
2870 ALL members of this multicast group have "sibling"
2871 relationship with it, not "parent". This is to a multicast
2872 group when the requested object would be fetched only from
2873 a "parent" cache, anyway. It's useful, e.g., when
2874 configuring a pool of redundant Squid proxies, being
2875 members of the same multicast group.
2878 ==== PEER SELECTION OPTIONS ====
2880 weight=N use to affect the selection of a peer during any weighted
2881 peer-selection mechanisms.
2882 The weight must be an integer; default is 1,
2883 larger weights are favored more.
2884 This option does not affect parent selection if a peering
2885 protocol is not in use.
2887 basetime=N Specify a base amount to be subtracted from round trip
2889 It is subtracted before division by weight in calculating
2890 which parent to fectch from. If the rtt is less than the
2891 base time the rtt is set to a minimal value.
2893 ttl=N Specify a TTL to use when sending multicast ICP queries
2895 Only useful when sending to a multicast group.
2896 Because we don't accept ICP replies from random
2897 hosts, you must configure other group members as
2898 peers with the 'multicast-responder' option.
2900 no-delay To prevent access to this neighbor from influencing the
2903 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2904 enabled) for this host from the specified URL rather
2905 than the Squid default location.
2908 ==== CARP OPTIONS ====
2910 carp-key=key-specification
2911 use a different key than the full URL to hash against the peer.
2912 the key-specification is a comma-separated list of the keywords
2913 scheme, host, port, path, params
2914 Order is not important.
2916 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2918 originserver Causes this parent to be contacted as an origin server.
2919 Meant to be used in accelerator setups when the peer
2923 Set the Host header of requests forwarded to this peer.
2924 Useful in accelerator setups where the server (peer)
2925 expects a certain domain name but clients may request
2926 others. ie example.com or www.example.com
2928 no-digest Disable request of cache digests.
2931 Disables requesting ICMP RTT database (NetDB).
2934 ==== AUTHENTICATION OPTIONS ====
2937 If this is a personal/workgroup proxy and your parent
2938 requires proxy authentication.
2940 Note: The string can include URL escapes (i.e. %20 for
2941 spaces). This also means % must be written as %%.
2944 Send login details received from client to this peer.
2945 Both Proxy- and WWW-Authorization headers are passed
2946 without alteration to the peer.
2947 Authentication is not required by Squid for this to work.
2949 Note: This will pass any form of authentication but
2950 only Basic auth will work through a proxy unless the
2951 connection-auth options are also used.
2953 login=PASS Send login details received from client to this peer.
2954 Authentication is not required by this option.
2956 If there are no client-provided authentication headers
2957 to pass on, but username and password are available
2958 from an external ACL user= and password= result tags
2959 they may be sent instead.
2961 Note: To combine this with proxy_auth both proxies must
2962 share the same user database as HTTP only allows for
2963 a single login (one for proxy, one for origin server).
2964 Also be warned this will expose your users proxy
2965 password to the peer. USE WITH CAUTION
2968 Send the username to the upstream cache, but with a
2969 fixed password. This is meant to be used when the peer
2970 is in another administrative domain, but it is still
2971 needed to identify each user.
2972 The star can optionally be followed by some extra
2973 information which is added to the username. This can
2974 be used to identify this proxy to the peer, similar to
2975 the login=username:password option above.
2978 If this is a personal/workgroup proxy and your parent
2979 requires a secure proxy authentication.
2980 The first principal from the default keytab or defined by
2981 the environment variable KRB5_KTNAME will be used.
2983 WARNING: The connection may transmit requests from multiple
2984 clients. Negotiate often assumes end-to-end authentication
2985 and a single-client. Which is not strictly true here.
2987 login=NEGOTIATE:principal_name
2988 If this is a personal/workgroup proxy and your parent
2989 requires a secure proxy authentication.
2990 The principal principal_name from the default keytab or
2991 defined by the environment variable KRB5_KTNAME will be
2994 WARNING: The connection may transmit requests from multiple
2995 clients. Negotiate often assumes end-to-end authentication
2996 and a single-client. Which is not strictly true here.
2998 connection-auth=on|off
2999 Tell Squid that this peer does or not support Microsoft
3000 connection oriented authentication, and any such
3001 challenges received from there should be ignored.
3002 Default is auto to automatically determine the status
3006 ==== SSL / HTTPS / TLS OPTIONS ====
3008 ssl Encrypt connections to this peer with SSL/TLS.
3010 sslcert=/path/to/ssl/certificate
3011 A client SSL certificate to use when connecting to
3014 sslkey=/path/to/ssl/key
3015 The private SSL key corresponding to sslcert above.
3016 If 'sslkey' is not specified 'sslcert' is assumed to
3017 reference a combined file containing both the
3018 certificate and the key.
3020 sslversion=1|2|3|4|5|6
3021 The SSL version to use when connecting to this peer
3022 1 = automatic (default)
3029 sslcipher=... The list of valid SSL ciphers to use when connecting
3032 ssloptions=... Specify various SSL implementation options:
3034 NO_SSLv2 Disallow the use of SSLv2
3035 NO_SSLv3 Disallow the use of SSLv3
3036 NO_TLSv1 Disallow the use of TLSv1.0
3037 NO_TLSv1_1 Disallow the use of TLSv1.1
3038 NO_TLSv1_2 Disallow the use of TLSv1.2
3040 Always create a new key when using
3041 temporary/ephemeral DH key exchanges
3042 ALL Enable various bug workarounds
3043 suggested as "harmless" by OpenSSL
3044 Be warned that this reduces SSL/TLS
3045 strength to some attacks.
3047 See the OpenSSL SSL_CTX_set_options documentation for a
3050 sslcafile=... A file containing additional CA certificates to use
3051 when verifying the peer certificate.
3053 sslcapath=... A directory containing additional CA certificates to
3054 use when verifying the peer certificate.
3056 sslcrlfile=... A certificate revocation list file to use when
3057 verifying the peer certificate.
3059 sslflags=... Specify various flags modifying the SSL implementation:
3062 Accept certificates even if they fail to
3065 Don't use the default CA list built in
3068 Don't verify the peer certificate
3069 matches the server name
3071 ssldomain= The peer name as advertised in it's certificate.
3072 Used for verifying the correctness of the received peer
3073 certificate. If not specified the peer hostname will be
3077 Enable the "Front-End-Https: On" header needed when
3078 using Squid as a SSL frontend in front of Microsoft OWA.
3079 See MS KB document Q307347 for details on this header.
3080 If set to auto the header will only be added if the
3081 request is forwarded as a https:// URL.
3084 ==== GENERAL OPTIONS ====
3087 A peer-specific connect timeout.
3088 Also see the peer_connect_timeout directive.
3090 connect-fail-limit=N
3091 How many times connecting to a peer must fail before
3092 it is marked as down. Default is 10.
3094 allow-miss Disable Squid's use of only-if-cached when forwarding
3095 requests to siblings. This is primarily useful when
3096 icp_hit_stale is used by the sibling. To extensive use
3097 of this option may result in forwarding loops, and you
3098 should avoid having two-way peerings with this option.
3099 For example to deny peer usage on requests from peer
3100 by denying cache_peer_access if the source is a peer.
3102 max-conn=N Limit the amount of connections Squid may open to this
3105 name=xxx Unique name for the peer.
3106 Required if you have multiple peers on the same host
3107 but different ports.
3108 This name can be used in cache_peer_access and similar
3109 directives to dentify the peer.
3110 Can be used by outgoing access controls through the
3113 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3114 requests to this peer. Use normal address selection instead.
3115 This overrides the spoof_client_ip ACL.
3117 proxy-only objects fetched from the peer will not be stored locally.
3121 NAME: cache_peer_domain cache_host_domain
3126 Use to limit the domains for which a neighbor cache will be
3130 cache_peer_domain cache-host domain [domain ...]
3131 cache_peer_domain cache-host !domain
3133 For example, specifying
3135 cache_peer_domain parent.foo.net .edu
3137 has the effect such that UDP query packets are sent to
3138 'bigserver' only when the requested object exists on a
3139 server in the .edu domain. Prefixing the domainname
3140 with '!' means the cache will be queried for objects
3143 NOTE: * Any number of domains may be given for a cache-host,
3144 either on the same or separate lines.
3145 * When multiple domains are given for a particular
3146 cache-host, the first matched domain is applied.
3147 * Cache hosts with no domain restrictions are queried
3149 * There are no defaults.
3150 * There is also a 'cache_peer_access' tag in the ACL
3154 NAME: cache_peer_access
3159 Similar to 'cache_peer_domain' but provides more flexibility by
3163 cache_peer_access cache-host allow|deny [!]aclname ...
3165 The syntax is identical to 'http_access' and the other lists of
3166 ACL elements. See the comments for 'http_access' below, or
3167 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
3170 NAME: neighbor_type_domain
3171 TYPE: hostdomaintype
3173 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3176 Modify the cache_peer neighbor type when passing requests
3177 about specific domains to the peer.
3180 neighbor_type_domain neighbor parent|sibling domain domain ...
3183 cache_peer foo.example.com parent 3128 3130
3184 neighbor_type_domain foo.example.com sibling .au .de
3186 The above configuration treats all requests to foo.example.com as a
3187 parent proxy unless the request is for a .au or .de ccTLD domain name.
3190 NAME: dead_peer_timeout
3194 LOC: Config.Timeout.deadPeer
3196 This controls how long Squid waits to declare a peer cache
3197 as "dead." If there are no ICP replies received in this
3198 amount of time, Squid will declare the peer dead and not
3199 expect to receive any further ICP replies. However, it
3200 continues to send ICP queries, and will mark the peer as
3201 alive upon receipt of the first subsequent ICP reply.
3203 This timeout also affects when Squid expects to receive ICP
3204 replies from peers. If more than 'dead_peer' seconds have
3205 passed since the last ICP reply was received, Squid will not
3206 expect to receive an ICP reply on the next query. Thus, if
3207 your time between requests is greater than this timeout, you
3208 will see a lot of requests sent DIRECT to origin servers
3209 instead of to your parents.
3212 NAME: forward_max_tries
3215 LOC: Config.forward_max_tries
3217 Controls how many different forward paths Squid will try
3218 before giving up. See also forward_timeout.
3220 NOTE: connect_retries (default: none) can make each of these
3221 possible forwarding paths be tried multiple times.
3224 NAME: hierarchy_stoplist
3227 LOC: Config.hierarchy_stoplist
3229 A list of words which, if found in a URL, cause the object to
3230 be handled directly by this cache. In other words, use this
3231 to not query neighbor caches for certain objects. You may
3232 list this option multiple times.
3235 hierarchy_stoplist cgi-bin ?
3237 Note: never_direct overrides this option.
3241 MEMORY CACHE OPTIONS
3242 -----------------------------------------------------------------------------
3249 LOC: Config.memMaxSize
3251 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3252 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3253 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3254 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3256 'cache_mem' specifies the ideal amount of memory to be used
3258 * In-Transit objects
3260 * Negative-Cached objects
3262 Data for these objects are stored in 4 KB blocks. This
3263 parameter specifies the ideal upper limit on the total size of
3264 4 KB blocks allocated. In-Transit objects take the highest
3267 In-transit objects have priority over the others. When
3268 additional space is needed for incoming data, negative-cached
3269 and hot objects will be released. In other words, the
3270 negative-cached and hot objects will fill up any unused space
3271 not needed for in-transit objects.
3273 If circumstances require, this limit will be exceeded.
3274 Specifically, if your incoming request rate requires more than
3275 'cache_mem' of memory to hold in-transit objects, Squid will
3276 exceed this limit to satisfy the new requests. When the load
3277 decreases, blocks will be freed until the high-water mark is
3278 reached. Thereafter, blocks will be used to store hot
3281 If shared memory caching is enabled, Squid does not use the shared
3282 cache space for in-transit objects, but they still consume as much
3283 local memory as they need. For more details about the shared memory
3284 cache, see memory_cache_shared.
3287 NAME: maximum_object_size_in_memory
3291 LOC: Config.Store.maxInMemObjSize
3293 Objects greater than this size will not be attempted to kept in
3294 the memory cache. This should be set high enough to keep objects
3295 accessed frequently in memory to improve performance whilst low
3296 enough to keep larger objects from hoarding cache_mem.
3299 NAME: memory_cache_shared
3302 LOC: Config.memShared
3304 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3306 Controls whether the memory cache is shared among SMP workers.
3308 The shared memory cache is meant to occupy cache_mem bytes and replace
3309 the non-shared memory cache, although some entities may still be
3310 cached locally by workers for now (e.g., internal and in-transit
3311 objects may be served from a local memory cache even if shared memory
3312 caching is enabled).
3314 By default, the memory cache is shared if and only if all of the
3315 following conditions are satisfied: Squid runs in SMP mode with
3316 multiple workers, cache_mem is positive, and Squid environment
3317 supports required IPC primitives (e.g., POSIX shared memory segments
3318 and GCC-style atomic operations).
3320 To avoid blocking locks, shared memory uses opportunistic algorithms
3321 that do not guarantee that every cachable entity that could have been
3322 shared among SMP workers will actually be shared.
3324 Currently, entities exceeding 32KB in size cannot be shared.
3327 NAME: memory_cache_mode
3331 DEFAULT_DOC: Keep the most recently fetched objects in memory
3333 Controls which objects to keep in the memory cache (cache_mem)
3335 always Keep most recently fetched objects in memory (default)
3337 disk Only disk cache hits are kept in memory, which means
3338 an object must first be cached on disk and then hit
3339 a second time before cached in memory.
3341 network Only objects fetched from network is kept in memory
3344 NAME: memory_replacement_policy
3346 LOC: Config.memPolicy
3349 The memory replacement policy parameter determines which
3350 objects are purged from memory when memory space is needed.
3352 See cache_replacement_policy for details on algorithms.
3357 -----------------------------------------------------------------------------
3360 NAME: cache_replacement_policy
3362 LOC: Config.replPolicy
3365 The cache replacement policy parameter determines which
3366 objects are evicted (replaced) when disk space is needed.
3368 lru : Squid's original list based LRU policy
3369 heap GDSF : Greedy-Dual Size Frequency
3370 heap LFUDA: Least Frequently Used with Dynamic Aging
3371 heap LRU : LRU policy implemented using a heap
3373 Applies to any cache_dir lines listed below this directive.
3375 The LRU policies keeps recently referenced objects.
3377 The heap GDSF policy optimizes object hit rate by keeping smaller
3378 popular objects in cache so it has a better chance of getting a
3379 hit. It achieves a lower byte hit rate than LFUDA though since
3380 it evicts larger (possibly popular) objects.
3382 The heap LFUDA policy keeps popular objects in cache regardless of
3383 their size and thus optimizes byte hit rate at the expense of
3384 hit rate since one large, popular object will prevent many
3385 smaller, slightly less popular objects from being cached.
3387 Both policies utilize a dynamic aging mechanism that prevents
3388 cache pollution that can otherwise occur with frequency-based
3389 replacement policies.
3391 NOTE: if using the LFUDA replacement policy you should increase
3392 the value of maximum_object_size above its default of 4 MB to
3393 to maximize the potential byte hit rate improvement of LFUDA.
3395 For more information about the GDSF and LFUDA cache replacement
3396 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3397 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3403 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3404 LOC: Config.cacheSwap
3407 cache_dir Type Directory-Name Fs-specific-data [options]
3409 You can specify multiple cache_dir lines to spread the
3410 cache among different disk partitions.
3412 Type specifies the kind of storage system to use. Only "ufs"
3413 is built by default. To enable any of the other storage systems
3414 see the --enable-storeio configure option.
3416 'Directory' is a top-level directory where cache swap
3417 files will be stored. If you want to use an entire disk
3418 for caching, this can be the mount-point directory.
3419 The directory must exist and be writable by the Squid
3420 process. Squid will NOT create this directory for you.
3422 In SMP configurations, cache_dir must not precede the workers option
3423 and should use configuration macros or conditionals to give each
3424 worker interested in disk caching a dedicated cache directory.
3427 ==== The ufs store type ====
3429 "ufs" is the old well-known Squid storage format that has always
3433 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3435 'Mbytes' is the amount of disk space (MB) to use under this
3436 directory. The default is 100 MB. Change this to suit your
3437 configuration. Do NOT put the size of your disk drive here.
3438 Instead, if you want Squid to use the entire disk drive,
3439 subtract 20% and use that value.
3441 'L1' is the number of first-level subdirectories which
3442 will be created under the 'Directory'. The default is 16.
3444 'L2' is the number of second-level subdirectories which
3445 will be created under each first-level directory. The default
3449 ==== The aufs store type ====
3451 "aufs" uses the same storage format as "ufs", utilizing
3452 POSIX-threads to avoid blocking the main Squid process on
3453 disk-I/O. This was formerly known in Squid as async-io.
3456 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3458 see argument descriptions under ufs above
3461 ==== The diskd store type ====
3463 "diskd" uses the same storage format as "ufs", utilizing a
3464 separate process to avoid blocking the main Squid process on
3468 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3470 see argument descriptions under ufs above
3472 Q1 specifies the number of unacknowledged I/O requests when Squid
3473 stops opening new files. If this many messages are in the queues,
3474 Squid won't open new files. Default is 64
3476 Q2 specifies the number of unacknowledged messages when Squid
3477 starts blocking. If this many messages are in the queues,
3478 Squid blocks until it receives some replies. Default is 72
3480 When Q1 < Q2 (the default), the cache directory is optimized
3481 for lower response time at the expense of a decrease in hit
3482 ratio. If Q1 > Q2, the cache directory is optimized for
3483 higher hit ratio at the expense of an increase in response
3487 ==== The rock store type ====
3490 cache_dir rock Directory-Name Mbytes [options]
3492 The Rock Store type is a database-style storage. All cached
3493 entries are stored in a "database" file, using fixed-size slots.
3494 A single entry occupies one or more slots.
3496 If possible, Squid using Rock Store creates a dedicated kid
3497 process called "disker" to avoid blocking Squid worker(s) on disk
3498 I/O. One disker kid is created for each rock cache_dir. Diskers
3499 are created only when Squid, running in daemon mode, has support
3500 for the IpcIo disk I/O module.
3502 swap-timeout=msec: Squid will not start writing a miss to or
3503 reading a hit from disk if it estimates that the swap operation
3504 will take more than the specified number of milliseconds. By
3505 default and when set to zero, disables the disk I/O time limit
3506 enforcement. Ignored when using blocking I/O module because
3507 blocking synchronous I/O does not allow Squid to estimate the
3508 expected swap wait time.
3510 max-swap-rate=swaps/sec: Artificially limits disk access using
3511 the specified I/O rate limit. Swap out requests that
3512 would cause the average I/O rate to exceed the limit are
3513 delayed. Individual swap in requests (i.e., hits or reads) are
3514 not delayed, but they do contribute to measured swap rate and
3515 since they are placed in the same FIFO queue as swap out
3516 requests, they may wait longer if max-swap-rate is smaller.
3517 This is necessary on file systems that buffer "too
3518 many" writes and then start blocking Squid and other processes
3519 while committing those writes to disk. Usually used together
3520 with swap-timeout to avoid excessive delays and queue overflows
3521 when disk demand exceeds available disk "bandwidth". By default
3522 and when set to zero, disables the disk I/O rate limit
3523 enforcement. Currently supported by IpcIo module only.
3525 slot-size=bytes: The size of a database "record" used for
3526 storing cached responses. A cached response occupies at least
3527 one slot and all database I/O is done using individual slots so
3528 increasing this parameter leads to more disk space waste while
3529 decreasing it leads to more disk I/O overheads. Should be a
3530 multiple of your operating system I/O page size. Defaults to
3531 16KBytes. A housekeeping header is stored with each slot and
3532 smaller slot-sizes will be rejected. The header is smaller than
3536 ==== COMMON OPTIONS ====
3538 no-store no new objects should be stored to this cache_dir.
3540 min-size=n the minimum object size in bytes this cache_dir
3541 will accept. It's used to restrict a cache_dir
3542 to only store large objects (e.g. AUFS) while
3543 other stores are optimized for smaller objects
3547 max-size=n the maximum object size in bytes this cache_dir
3549 The value in maximum_object_size directive, sets
3550 a default unless more specific details are available
3551 about the cache_dir (ie a small store capacity).
3553 Note: To make optimal use of the max-size limits you should order
3554 the cache_dir lines with the smallest max-size value first.
3558 # Uncomment and adjust the following to add a disk cache directory.
3559 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3563 NAME: store_dir_select_algorithm
3565 LOC: Config.store_dir_select_algorithm
3568 How Squid selects which cache_dir to use when the response
3569 object will fit into more than one.
3571 Regardless of which algorithm is used the cache_dir min-size
3572 and max-size parameters are obeyed. As such they can affect
3573 the selection algorithm by limiting the set of considered
3580 This algorithm is suited to caches with similar cache_dir
3581 sizes and disk speeds.
3583 The disk with the least I/O pending is selected.
3584 When there are multiple disks with the same I/O load ranking
3585 the cache_dir with most available capacity is selected.
3587 When a mix of cache_dir sizes are configured the faster disks
3588 have a naturally lower I/O loading and larger disks have more
3589 capacity. So space used to store objects and data throughput
3590 may be very unbalanced towards larger disks.
3595 This algorithm is suited to caches with unequal cache_dir
3598 Each cache_dir is selected in a rotation. The next suitable
3601 Available cache_dir capacity is only considered in relation
3602 to whether the object will fit and meets the min-size and
3603 max-size parameters.
3605 Disk I/O loading is only considered to prevent overload on slow
3606 disks. This algorithm does not spread objects by size, so any
3607 I/O loading per-disk may appear very unbalanced and volatile.
3611 NAME: max_open_disk_fds
3613 LOC: Config.max_open_disk_fds
3615 DEFAULT_DOC: no limit
3617 To avoid having disk as the I/O bottleneck Squid can optionally
3618 bypass the on-disk cache if more than this amount of disk file
3619 descriptors are open.
3621 A value of 0 indicates no limit.
3624 NAME: minimum_object_size
3628 DEFAULT_DOC: no limit
3629 LOC: Config.Store.minObjectSize
3631 Objects smaller than this size will NOT be saved on disk. The
3632 value is specified in bytes, and the default is 0 KB, which
3633 means all responses can be stored.
3636 NAME: maximum_object_size
3640 LOC: Config.Store.maxObjectSize
3642 The default limit on size of objects stored to disk.
3643 This size is used for cache_dir where max-size is not set.
3644 The value is specified in bytes, and the default is 4 MB.
3646 If you wish to get a high BYTES hit ratio, you should probably
3647 increase this (one 32 MB object hit counts for 3200 10KB
3650 If you wish to increase hit ratio more than you want to
3651 save bandwidth you should leave this low.
3653 NOTE: if using the LFUDA replacement policy you should increase
3654 this value to maximize the byte hit rate improvement of LFUDA!
3655 See replacement_policy below for a discussion of this policy.
3658 NAME: cache_swap_low
3659 COMMENT: (percent, 0-100)
3662 LOC: Config.Swap.lowWaterMark
3664 The low-water mark for cache object replacement.
3665 Replacement begins when the swap (disk) usage is above the
3666 low-water mark and attempts to maintain utilization near the
3667 low-water mark. As swap utilization gets close to high-water
3668 mark object eviction becomes more aggressive. If utilization is
3669 close to the low-water mark less replacement is done each time.
3671 Defaults are 90% and 95%. If you have a large cache, 5% could be
3672 hundreds of MB. If this is the case you may wish to set these
3673 numbers closer together.
3675 See also cache_swap_high
3678 NAME: cache_swap_high
3679 COMMENT: (percent, 0-100)
3682 LOC: Config.Swap.highWaterMark
3684 The high-water mark for cache object replacement.
3685 Replacement begins when the swap (disk) usage is above the
3686 low-water mark and attempts to maintain utilization near the
3687 low-water mark. As swap utilization gets close to high-water
3688 mark object eviction becomes more aggressive. If utilization is
3689 close to the low-water mark less replacement is done each time.
3691 Defaults are 90% and 95%. If you have a large cache, 5% could be
3692 hundreds of MB. If this is the case you may wish to set these
3693 numbers closer together.
3695 See also cache_swap_low
3700 -----------------------------------------------------------------------------
3707 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
3711 logformat <name> <format specification>
3713 Defines an access log format.
3715 The <format specification> is a string with embedded % format codes
3717 % format codes all follow the same basic structure where all but
3718 the formatcode is optional. Output strings are automatically escaped
3719 as required according to their context and the output format
3720 modifiers are usually not needed, but can be specified if an explicit
3721 output format is desired.
3723 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3725 " output in quoted string format
3726 [ output in squid text log format as used by log_mime_hdrs
3727 # output in URL quoted format
3732 width minimum and/or maximum field width:
3733 [width_min][.width_max]
3734 When minimum starts with 0, the field is zero-padded.
3735 String values exceeding maximum width are truncated.
3737 {arg} argument such as header name etc
3741 % a literal % character
3742 sn Unique sequence number per log line entry
3743 err_code The ID of an error response served by Squid or
3744 a similar internal error identifier.
3745 err_detail Additional err_code-dependent error information.
3746 note The meta header specified by the argument. Also
3747 logs the adaptation meta headers set by the
3748 adaptation_meta configuration parameter.
3749 If no argument given all meta headers logged.
3751 Connection related format codes:
3753 >a Client source IP address
3755 >p Client source port
3756 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3757 >la Local IP address the client connected to
3758 >lp Local port number the client connected to
3759 >qos Client connection TOS/DSCP value set by Squid
3760 >nfmark Client connection netfilter mark set by Squid
3762 la Local listening IP address the client connection was connected to.
3763 lp Local listening port number the client connection was connected to.
3765 <a Server IP address of the last server or peer connection
3766 <A Server FQDN or peer name
3767 <p Server port number of the last server or peer connection
3768 <la Local IP address of the last server or peer connection
3769 <lp Local port number of the last server or peer connection
3770 <qos Server connection TOS/DSCP value set by Squid
3771 <nfmark Server connection netfilter mark set by Squid
3773 Time related format codes:
3775 ts Seconds since epoch
3776 tu subsecond time (milliseconds)
3777 tl Local time. Optional strftime format argument
3778 default %d/%b/%Y:%H:%M:%S %z
3779 tg GMT time. Optional strftime format argument
3780 default %d/%b/%Y:%H:%M:%S %z
3781 tr Response time (milliseconds)
3782 dt Total time spent making DNS lookups (milliseconds)
3783 tS Approximate master transaction start time in
3784 <full seconds since epoch>.<fractional seconds> format.
3785 Currently, Squid considers the master transaction
3786 started when a complete HTTP request header initiating
3787 the transaction is received from the client. This is
3788 the same value that Squid uses to calculate transaction
3789 response time when logging %tr to access.log. Currently,
3790 Squid uses millisecond resolution for %tS values,
3791 similar to the default access.log "current time" field
3794 Access Control related format codes:
3796 et Tag returned by external acl
3797 ea Log string returned by external acl
3798 un User name (any available)
3799 ul User name from authentication
3800 ue User name from external acl helper
3801 ui User name from ident
3802 us User name from SSL
3803 credentials Client credentials. The exact meaning depends on
3804 the authentication scheme: For Basic authentication,
3805 it is the password; for Digest, the realm sent by the
3806 client; for NTLM and Negotiate, the client challenge
3807 or client credentials prefixed with "YR " or "KK ".
3809 HTTP related format codes:
3813 [http::]rm Request method (GET/POST etc)
3814 [http::]>rm Request method from client
3815 [http::]<rm Request method sent to server or peer
3816 [http::]ru Request URL from client (historic, filtered for logging)
3817 [http::]>ru Request URL from client
3818 [http::]<ru Request URL sent to server or peer
3819 [http::]>rd Request URL domain from client
3820 [http::]rp Request URL-Path excluding hostname
3821 [http::]>rp Request URL-Path excluding hostname from client
3822 [http::]<rp Request URL-Path excluding hostname sent to server or peer
3823 [http::]rv Request protocol version
3824 [http::]>rv Request protocol version from client
3825 [http::]<rv Request protocol version sent to server or peer
3827 [http::]>h Original received request header.
3828 Usually differs from the request header sent by
3829 Squid, although most fields are often preserved.
3830 Accepts optional header field name/value filter
3831 argument using name[:[separator]element] format.
3832 [http::]>ha Received request header after adaptation and
3833 redirection (pre-cache REQMOD vectoring point).
3834 Usually differs from the request header sent by
3835 Squid, although most fields are often preserved.
3836 Optional header name argument as for >h
3841 [http::]<Hs HTTP status code received from the next hop
3842 [http::]>Hs HTTP status code sent to the client
3844 [http::]<h Reply header. Optional header name argument
3847 [http::]mt MIME content type
3852 [http::]st Total size of request + reply traffic with client
3853 [http::]>st Total size of request received from client.
3854 Excluding chunked encoding bytes.
3855 [http::]<st Total size of reply sent to client (after adaptation)
3857 [http::]>sh Size of request headers received from client
3858 [http::]<sh Size of reply headers sent to client (after adaptation)
3860 [http::]<sH Reply high offset sent
3861 [http::]<sS Upstream object size
3863 [http::]<bs Number of HTTP-equivalent message body bytes
3864 received from the next hop, excluding chunked
3865 transfer encoding and control messages.
3866 Generated FTP/Gopher listings are treated as
3872 [http::]<pt Peer response time in milliseconds. The timer starts
3873 when the last request byte is sent to the next hop
3874 and stops when the last response byte is received.
3875 [http::]<tt Total server-side time in milliseconds. The timer
3876 starts with the first connect request (or write I/O)
3877 sent to the first selected peer. The timer stops
3878 with the last I/O with the last peer.
3880 Squid handling related format codes:
3882 Ss Squid request status (TCP_MISS etc)
3883 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3885 SSL-related format codes:
3887 ssl::bump_mode SslBump decision for the transaction:
3889 For CONNECT requests that initiated bumping of
3890 a connection and for any request received on
3891 an already bumped connection, Squid logs the
3892 corresponding SslBump mode ("server-first" or
3893 "client-first"). See the ssl_bump option for
3894 more information about these modes.
3896 A "none" token is logged for requests that
3897 triggered "ssl_bump" ACL evaluation matching
3898 either a "none" rule or no rules at all.
3900 In all other cases, a single dash ("-") is
3903 If ICAP is enabled, the following code becomes available (as
3904 well as ICAP log codes documented with the icap_log option):
3906 icap::tt Total ICAP processing time for the HTTP
3907 transaction. The timer ticks when ICAP
3908 ACLs are checked and when ICAP
3909 transaction is in progress.
3911 If adaptation is enabled the following three codes become available:
3913 adapt::<last_h The header of the last ICAP response or
3914 meta-information from the last eCAP
3915 transaction related to the HTTP transaction.
3916 Like <h, accepts an optional header name
3919 adapt::sum_trs Summed adaptation transaction response
3920 times recorded as a comma-separated list in
3921 the order of transaction start time. Each time
3922 value is recorded as an integer number,
3923 representing response time of one or more
3924 adaptation (ICAP or eCAP) transaction in
3925 milliseconds. When a failed transaction is
3926 being retried or repeated, its time is not
3927 logged individually but added to the
3928 replacement (next) transaction. See also:
3931 adapt::all_trs All adaptation transaction response times.
3932 Same as adaptation_strs but response times of
3933 individual transactions are never added
3934 together. Instead, all transaction response
3935 times are recorded individually.
3937 You can prefix adapt::*_trs format codes with adaptation
3938 service name in curly braces to record response time(s) specific
3939 to that service. For example: %{my_service}adapt::sum_trs
3941 If SSL is enabled, the following formating codes become available:
3943 %ssl::>cert_subject The Subject field of the received client
3944 SSL certificate or a dash ('-') if Squid has
3945 received an invalid/malformed certificate or
3946 no certificate at all. Consider encoding the
3947 logged value because Subject often has spaces.
3949 %ssl::>cert_issuer The Issuer field of the received client
3950 SSL certificate or a dash ('-') if Squid has
3951 received an invalid/malformed certificate or
3952 no certificate at all. Consider encoding the
3953 logged value because Issuer often has spaces.
3955 The default formats available (which do not need re-defining) are:
3957 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3958 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3959 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3960 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3961 logformat useragent %>a [%tl] "%{User-Agent}>h"
3963 NOTE: When the log_mime_hdrs directive is set to ON.
3964 The squid, common and combined formats have a safely encoded copy
3965 of the mime headers appended to each line within a pair of brackets.
3967 NOTE: The common and combined formats are not quite true to the Apache definition.
3968 The logs from Squid contain an extra status and hierarchy code appended.
3972 NAME: access_log cache_access_log
3974 LOC: Config.Log.accesslogs
3975 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3977 Configures whether and how Squid logs HTTP and ICP transactions.
3978 If access logging is enabled, a single line is logged for every
3979 matching HTTP or ICP request. The recommended directive formats are:
3981 access_log <module>:<place> [option ...] [acl acl ...]
3982 access_log none [acl acl ...]
3984 The following directive format is accepted but may be deprecated:
3985 access_log <module>:<place> [<logformat name> [acl acl ...]]
3987 In most cases, the first ACL name must not contain the '=' character
3988 and should not be equal to an existing logformat name. You can always
3989 start with an 'all' ACL to work around those restrictions.
3991 Will log to the specified module:place using the specified format (which
3992 must be defined in a logformat directive) those entries which match
3993 ALL the acl's specified (which must be defined in acl clauses).
3994 If no acl is specified, all requests will be logged to this destination.
3996 ===== Available options for the recommended directive format =====
3998 logformat=name Names log line format (either built-in or
3999 defined by a logformat directive). Defaults
4002 buffer-size=64KB Defines approximate buffering limit for log
4003 records (see buffered_logs). Squid should not
4004 keep more than the specified size and, hence,
4005 should flush records before the buffer becomes
4006 full to avoid overflows under normal
4007 conditions (the exact flushing algorithm is
4008 module-dependent though). The on-error option
4009 controls overflow handling.
4011 on-error=die|drop Defines action on unrecoverable errors. The
4012 'drop' action ignores (i.e., does not log)
4013 affected log records. The default 'die' action
4014 kills the affected worker. The drop action
4015 support has not been tested for modules other
4018 ===== Modules Currently available =====
4020 none Do not log any requests matching these ACL.
4021 Do not specify Place or logformat name.
4023 stdio Write each log line to disk immediately at the completion of
4025 Place: the filename and path to be written.
4027 daemon Very similar to stdio. But instead of writing to disk the log
4028 line is passed to a daemon helper for asychronous handling instead.
4029 Place: varies depending on the daemon.
4031 log_file_daemon Place: the file name and path to be written.
4033 syslog To log each request via syslog facility.
4034 Place: The syslog facility and priority level for these entries.
4035 Place Format: facility.priority
4037 where facility could be any of:
4038 authpriv, daemon, local0 ... local7 or user.
4040 And priority could be any of:
4041 err, warning, notice, info, debug.
4043 udp To send each log line as text data to a UDP receiver.
4044 Place: The destination host name or IP and port.
4045 Place Format: //host:port
4047 tcp To send each log line as text data to a TCP receiver.
4048 Lines may be accumulated before sending (see buffered_logs).
4049 Place: The destination host name or IP and port.
4050 Place Format: //host:port
4053 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4059 LOC: Config.Log.icaplogs
4062 ICAP log files record ICAP transaction summaries, one line per
4065 The icap_log option format is:
4066 icap_log <filepath> [<logformat name> [acl acl ...]]
4067 icap_log none [acl acl ...]]
4069 Please see access_log option documentation for details. The two
4070 kinds of logs share the overall configuration approach and many
4073 ICAP processing of a single HTTP message or transaction may
4074 require multiple ICAP transactions. In such cases, multiple
4075 ICAP transaction log lines will correspond to a single access
4078 ICAP log uses logformat codes that make sense for an ICAP
4079 transaction. Header-related codes are applied to the HTTP header
4080 embedded in an ICAP server response, with the following caveats:
4081 For REQMOD, there is no HTTP response header unless the ICAP
4082 server performed request satisfaction. For RESPMOD, the HTTP
4083 request header is the header sent to the ICAP server. For
4084 OPTIONS, there are no HTTP headers.
4086 The following format codes are also available for ICAP logs:
4088 icap::<A ICAP server IP address. Similar to <A.
4090 icap::<service_name ICAP service name from the icap_service
4091 option in Squid configuration file.
4093 icap::ru ICAP Request-URI. Similar to ru.
4095 icap::rm ICAP request method (REQMOD, RESPMOD, or
4096 OPTIONS). Similar to existing rm.
4098 icap::>st Bytes sent to the ICAP server (TCP payload
4099 only; i.e., what Squid writes to the socket).
4101 icap::<st Bytes received from the ICAP server (TCP
4102 payload only; i.e., what Squid reads from
4105 icap::<bs Number of message body bytes received from the
4106 ICAP server. ICAP message body, if any, usually
4107 includes encapsulated HTTP message headers and
4108 possibly encapsulated HTTP message body. The
4109 HTTP body part is dechunked before its size is
4112 icap::tr Transaction response time (in
4113 milliseconds). The timer starts when
4114 the ICAP transaction is created and
4115 stops when the transaction is completed.
4118 icap::tio Transaction I/O time (in milliseconds). The
4119 timer starts when the first ICAP request
4120 byte is scheduled for sending. The timers
4121 stops when the last byte of the ICAP response
4124 icap::to Transaction outcome: ICAP_ERR* for all
4125 transaction errors, ICAP_OPT for OPTION
4126 transactions, ICAP_ECHO for 204
4127 responses, ICAP_MOD for message
4128 modification, and ICAP_SAT for request
4129 satisfaction. Similar to Ss.
4131 icap::Hs ICAP response status code. Similar to Hs.
4133 icap::>h ICAP request header(s). Similar to >h.
4135 icap::<h ICAP response header(s). Similar to <h.
4137 The default ICAP log format, which can be used without an explicit
4138 definition, is called icap_squid:
4140 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
4142 See also: logformat, log_icap, and %adapt::<last_h
4145 NAME: logfile_daemon
4147 DEFAULT: @DEFAULT_LOGFILED@
4148 LOC: Log::TheConfig.logfile_daemon
4150 Specify the path to the logfile-writing daemon. This daemon is
4151 used to write the access and store logs, if configured.
4153 Squid sends a number of commands to the log daemon:
4154 L<data>\n - logfile data
4159 r<n>\n - set rotate count to <n>
4160 b<n>\n - 1 = buffer output, 0 = don't buffer output
4162 No responses is expected.
4168 Remove this line. Use acls with access_log directives to control access logging
4174 Remove this line. Use acls with icap_log directives to control icap logging
4177 NAME: stats_collection
4179 LOC: Config.accessList.stats_collection
4181 DEFAULT_DOC: Allow logging for all transactions.
4182 COMMENT: allow|deny acl acl...
4184 This options allows you to control which requests gets accounted
4185 in performance counters.
4187 This clause only supports fast acl types.
4188 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4191 NAME: cache_store_log
4194 LOC: Config.Log.store
4196 Logs the activities of the storage manager. Shows which
4197 objects are ejected from the cache, and which objects are
4198 saved and for how long.
4199 There are not really utilities to analyze this data, so you can safely
4200 disable it (the default).
4202 Store log uses modular logging outputs. See access_log for the list
4203 of modules supported.
4206 cache_store_log stdio:@DEFAULT_STORE_LOG@
4207 cache_store_log daemon:@DEFAULT_STORE_LOG@
4210 NAME: cache_swap_state cache_swap_log
4212 LOC: Config.Log.swap
4214 DEFAULT_DOC: Store the journal inside its cache_dir
4216 Location for the cache "swap.state" file. This index file holds
4217 the metadata of objects saved on disk. It is used to rebuild
4218 the cache during startup. Normally this file resides in each
4219 'cache_dir' directory, but you may specify an alternate
4220 pathname here. Note you must give a full filename, not just
4221 a directory. Since this is the index for the whole object
4222 list you CANNOT periodically rotate it!
4224 If %s can be used in the file name it will be replaced with a
4225 a representation of the cache_dir name where each / is replaced
4226 with '.'. This is needed to allow adding/removing cache_dir
4227 lines when cache_swap_log is being used.
4229 If have more than one 'cache_dir', and %s is not used in the name
4230 these swap logs will have names such as:
4236 The numbered extension (which is added automatically)
4237 corresponds to the order of the 'cache_dir' lines in this
4238 configuration file. If you change the order of the 'cache_dir'
4239 lines in this file, these index files will NOT correspond to
4240 the correct 'cache_dir' entry (unless you manually rename
4241 them). We recommend you do NOT use this option. It is
4242 better to keep these index files in each 'cache_dir' directory.
4245 NAME: logfile_rotate
4248 LOC: Config.Log.rotateNumber
4250 Specifies the number of logfile rotations to make when you
4251 type 'squid -k rotate'. The default is 10, which will rotate
4252 with extensions 0 through 9. Setting logfile_rotate to 0 will
4253 disable the file name rotation, but the logfiles are still closed
4254 and re-opened. This will enable you to rename the logfiles
4255 yourself just before sending the rotate signal.
4257 Note, the 'squid -k rotate' command normally sends a USR1
4258 signal to the running squid process. In certain situations
4259 (e.g. on Linux with Async I/O), USR1 is used for other
4260 purposes, so -k rotate uses another signal. It is best to get
4261 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4264 Note, from Squid-3.1 this option is only a default for cache.log,
4265 that log can be rotated separately by using debug_options.
4268 NAME: emulate_httpd_log
4271 Replace this with an access_log directive using the format 'common' or 'combined'.
4274 NAME: log_ip_on_direct
4277 Remove this option from your config. To log server or peer names use %<A in the log format.
4282 DEFAULT: @DEFAULT_MIME_TABLE@
4283 LOC: Config.mimeTablePathname
4285 Path to Squid's icon configuration file.
4287 You shouldn't need to change this, but the default file contains
4288 examples and formatting information if you do.
4294 LOC: Config.onoff.log_mime_hdrs
4297 The Cache can record both the request and the response MIME
4298 headers for each HTTP transaction. The headers are encoded
4299 safely and will appear as two bracketed fields at the end of
4300 the access log (for either the native or httpd-emulated log
4301 formats). To enable this logging set log_mime_hdrs to 'on'.
4307 Replace this with an access_log directive using the format 'useragent'.
4310 NAME: referer_log referrer_log
4313 Replace this with an access_log directive using the format 'referrer'.
4318 DEFAULT: @DEFAULT_PID_FILE@
4319 LOC: Config.pidFilename
4321 A filename to write the process-id to. To disable, enter "none".
4327 Remove this option from your config. To log FQDN use %>A in the log format.
4330 NAME: client_netmask
4332 LOC: Config.Addrs.client_netmask
4334 DEFAULT_DOC: Log full client IP address
4336 A netmask for client addresses in logfiles and cachemgr output.
4337 Change this to protect the privacy of your cache clients.
4338 A netmask of 255.255.255.0 will log all IP's in that range with
4339 the last digit set to '0'.
4345 Use a regular access.log with ACL limiting it to MISS events.
4348 NAME: strip_query_terms
4350 LOC: Config.onoff.strip_query_terms
4353 By default, Squid strips query terms from requested URLs before
4354 logging. This protects your user's privacy and reduces log size.
4356 When investigating HIT/MISS or other caching behaviour you
4357 will need to disable this to see the full URL used by Squid.
4364 LOC: Config.onoff.buffered_logs
4366 Whether to write/send access_log records ASAP or accumulate them and
4367 then write/send them in larger chunks. Buffering may improve
4368 performance because it decreases the number of I/Os. However,
4369 buffering increases the delay before log records become available to
4370 the final recipient (e.g., a disk file or logging daemon) and,
4371 hence, increases the risk of log records loss.
4373 Note that even when buffered_logs are off, Squid may have to buffer
4374 records if it cannot write/send them immediately due to pending I/Os
4375 (e.g., the I/O writing the previous log record) or connectivity loss.
4377 Currently honored by 'daemon' and 'tcp' access_log modules only.
4380 NAME: netdb_filename
4382 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4383 LOC: Config.netdbFilename
4386 Where Squid stores it's netdb journal.
4387 When enabled this journal preserves netdb state between restarts.
4389 To disable, enter "none".
4393 OPTIONS FOR TROUBLESHOOTING
4394 -----------------------------------------------------------------------------
4399 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4400 LOC: Debug::cache_log
4402 Squid administrative logging file.
4404 This is where general information about Squid behavior goes. You can
4405 increase the amount of data logged to this file and how often it is
4406 rotated with "debug_options"
4412 DEFAULT_DOC: Log all critical and important messages.
4413 LOC: Debug::debugOptions
4415 Logging options are set as section,level where each source file
4416 is assigned a unique section. Lower levels result in less
4417 output, Full debugging (level 9) can result in a very large
4418 log file, so be careful.
4420 The magic word "ALL" sets debugging levels for all sections.
4421 The default is to run with "ALL,1" to record important warnings.
4423 The rotate=N option can be used to keep more or less of these logs
4424 than would otherwise be kept by logfile_rotate.
4425 For most uses a single log should be enough to monitor current
4426 events affecting Squid.
4431 LOC: Config.coredump_dir
4432 DEFAULT_IF_NONE: none
4433 DEFAULT_DOC: Use the directory from where Squid was started.
4435 By default Squid leaves core files in the directory from where
4436 it was started. If you set 'coredump_dir' to a directory
4437 that exists, Squid will chdir() to that directory at startup
4438 and coredump files will be left there.
4442 # Leave coredumps in the first cache dir
4443 coredump_dir @DEFAULT_SWAP_DIR@
4449 OPTIONS FOR FTP GATEWAYING
4450 -----------------------------------------------------------------------------
4456 LOC: Config.Ftp.anon_user
4458 If you want the anonymous login password to be more informative
4459 (and enable the use of picky FTP servers), set this to something
4460 reasonable for your domain, like wwwuser@somewhere.net
4462 The reason why this is domainless by default is the
4463 request can be made on the behalf of a user in any domain,
4464 depending on how the cache is used.
4465 Some FTP server also validate the email address is valid
4466 (for example perl.com).
4472 LOC: Config.Ftp.passive
4474 If your firewall does not allow Squid to use passive
4475 connections, turn off this option.
4477 Use of ftp_epsv_all option requires this to be ON.
4483 LOC: Config.Ftp.epsv_all
4485 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4487 NATs may be able to put the connection on a "fast path" through the
4488 translator, as the EPRT command will never be used and therefore,
4489 translation of the data portion of the segments will never be needed.
4491 When a client only expects to do two-way FTP transfers this may be
4493 If squid finds that it must do a three-way FTP transfer after issuing
4494 an EPSV ALL command, the FTP session will fail.
4496 If you have any doubts about this option do not use it.
4497 Squid will nicely attempt all other connection methods.
4499 Requires ftp_passive to be ON (default) for any effect.
4505 LOC: Config.accessList.ftp_epsv
4507 FTP Protocol extensions permit the use of a special "EPSV" command.
4509 NATs may be able to put the connection on a "fast path" through the
4510 translator using EPSV, as the EPRT command will never be used
4511 and therefore, translation of the data portion of the segments
4512 will never be needed.
4514 EPSV is often required to interoperate with FTP servers on IPv6
4515 networks. On the other hand, it may break some IPv4 servers.
4517 By default, EPSV may try EPSV with any FTP server. To fine tune
4518 that decision, you may restrict EPSV to certain clients or servers
4521 ftp_epsv allow|deny al1 acl2 ...
4523 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
4525 Only fast ACLs are supported.
4526 Requires ftp_passive to be ON (default) for any effect.
4532 LOC: Config.Ftp.eprt
4534 FTP Protocol extensions permit the use of a special "EPRT" command.
4536 This extension provides a protocol neutral alternative to the
4537 IPv4-only PORT command. When supported it enables active FTP data
4538 channels over IPv6 and efficient NAT handling.
4540 Turning this OFF will prevent EPRT being attempted and will skip
4541 straight to using PORT for IPv4 servers.
4543 Some devices are known to not handle this extension correctly and
4544 may result in crashes. Devices which suport EPRT enough to fail
4545 cleanly will result in Squid attempting PORT anyway. This directive
4546 should only be disabled when EPRT results in device failures.
4548 WARNING: Doing so will convert Squid back to the old behavior with all
4549 the related problems with external NAT devices/layers and IPv4-only FTP.
4552 NAME: ftp_sanitycheck
4555 LOC: Config.Ftp.sanitycheck
4557 For security and data integrity reasons Squid by default performs
4558 sanity checks of the addresses of FTP data connections ensure the
4559 data connection is to the requested server. If you need to allow
4560 FTP connections to servers using another IP address for the data
4561 connection turn this off.
4564 NAME: ftp_telnet_protocol
4567 LOC: Config.Ftp.telnet
4569 The FTP protocol is officially defined to use the telnet protocol
4570 as transport channel for the control connection. However, many
4571 implementations are broken and does not respect this aspect of
4574 If you have trouble accessing files with ASCII code 255 in the
4575 path or similar problems involving this ASCII code you can
4576 try setting this directive to off. If that helps, report to the
4577 operator of the FTP server in question that their FTP server
4578 is broken and does not follow the FTP standard.
4582 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4583 -----------------------------------------------------------------------------
4588 DEFAULT: @DEFAULT_DISKD@
4589 LOC: Config.Program.diskd
4591 Specify the location of the diskd executable.
4592 Note this is only useful if you have compiled in
4593 diskd as one of the store io modules.
4596 NAME: unlinkd_program
4599 DEFAULT: @DEFAULT_UNLINKD@
4600 LOC: Config.Program.unlinkd
4602 Specify the location of the executable for file deletion process.
4605 NAME: pinger_program
4607 DEFAULT: @DEFAULT_PINGER@
4608 LOC: Config.pinger.program
4611 Specify the location of the executable for the pinger process.
4617 LOC: Config.pinger.enable
4620 Control whether the pinger is active at run-time.
4621 Enables turning ICMP pinger on and off with a simple
4622 squid -k reconfigure.
4627 OPTIONS FOR URL REWRITING
4628 -----------------------------------------------------------------------------
4631 NAME: url_rewrite_program redirect_program
4633 LOC: Config.Program.redirect
4636 Specify the location of the executable URL rewriter to use.
4637 Since they can perform almost any function there isn't one included.
4639 For each requested URL, the rewriter will receive on line with the format
4641 [channel-ID <SP>] URL [<SP> extras]<NL>
4644 After processing the request the helper must reply using the following format:
4646 [channel-ID <SP>] result [<SP> kv-pairs]
4648 The result code can be:
4650 OK status=30N url="..."
4651 Redirect the URL to the one supplied in 'url='.
4652 'status=' is optional and contains the status code to send
4653 the client in Squids HTTP response. It must be one of the
4654 HTTP redirect status codes: 301, 302, 303, 307, 308.
4655 When no status is given Squid will use 302.
4657 OK rewrite-url="..."
4658 Rewrite the URL to the one supplied in 'rewrite-url='.
4659 The new URL is fetched directly by Squid and returned to
4660 the client as the response to its request.
4663 When neither of url= and rewrite-url= are sent Squid does
4667 Do not change the URL.
4670 An internal error occurred in the helper, preventing
4671 a result being identified. The 'message=' key name is
4672 reserved for delivering a log message.
4675 In the future, the interface protocol will be extended with
4676 key=value pairs ("kv-pairs" shown above). Helper programs
4677 should be prepared to receive and possibly ignore additional
4678 whitespace-separated tokens on each input line.
4680 When using the concurrency= option the protocol is changed by
4681 introducing a query channel tag in front of the request/response.
4682 The query channel tag is a number between 0 and concurrency-1.
4683 This value must be echoed back unchanged to Squid as the first part
4684 of the response relating to its request.
4686 WARNING: URL re-writing ability should be avoided whenever possible.
4687 Use the URL redirect form of response instead.
4689 Re-write creates a difference in the state held by the client
4690 and server. Possibly causing confusion when the server response
4691 contains snippets of its view state. Embeded URLs, response
4692 and content Location headers, etc. are not re-written by this
4695 By default, a URL rewriter is not used.
4698 NAME: url_rewrite_children redirect_children
4699 TYPE: HelperChildConfig
4700 DEFAULT: 20 startup=0 idle=1 concurrency=0
4701 LOC: Config.redirectChildren
4703 The maximum number of redirector processes to spawn. If you limit
4704 it too few Squid will have to wait for them to process a backlog of
4705 URLs, slowing it down. If you allow too many they will use RAM
4706 and other system resources noticably.
4708 The startup= and idle= options allow some measure of skew in your
4713 Sets a minimum of how many processes are to be spawned when Squid
4714 starts or reconfigures. When set to zero the first request will
4715 cause spawning of the first child process to handle it.
4717 Starting too few will cause an initial slowdown in traffic as Squid
4718 attempts to simultaneously spawn enough processes to cope.
4722 Sets a minimum of how many processes Squid is to try and keep available
4723 at all times. When traffic begins to rise above what the existing
4724 processes can handle this many more will be spawned up to the maximum
4725 configured. A minimum setting of 1 is required.
4729 The number of requests each redirector helper can handle in
4730 parallel. Defaults to 0 which indicates the redirector
4731 is a old-style single threaded redirector.
4733 When this directive is set to a value >= 1 then the protocol
4734 used to communicate with the helper is modified to include
4735 an ID in front of the request/response. The ID from the request
4736 must be echoed back with the response to that request.
4739 NAME: url_rewrite_host_header redirect_rewrites_host_header
4742 LOC: Config.onoff.redir_rewrites_host
4744 To preserve same-origin security policies in browsers and
4745 prevent Host: header forgery by redirectors Squid rewrites
4746 any Host: header in redirected requests.
4748 If you are running an accelerator this may not be a wanted
4749 effect of a redirector. This directive enables you disable
4750 Host: alteration in reverse-proxy traffic.
4752 WARNING: Entries are cached on the result of the URL rewriting
4753 process, so be careful if you have domain-virtual hosts.
4755 WARNING: Squid and other software verifies the URL and Host
4756 are matching, so be careful not to relay through other proxies
4757 or inspecting firewalls with this disabled.
4760 NAME: url_rewrite_access redirector_access
4763 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4764 LOC: Config.accessList.redirector
4766 If defined, this access list specifies which requests are
4767 sent to the redirector processes.
4769 This clause supports both fast and slow acl types.
4770 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4773 NAME: url_rewrite_bypass redirector_bypass
4775 LOC: Config.onoff.redirector_bypass
4778 When this is 'on', a request will not go through the
4779 redirector if all the helpers are busy. If this is 'off'
4780 and the redirector queue grows too large, Squid will exit
4781 with a FATAL error and ask you to increase the number of
4782 redirectors. You should only enable this if the redirectors
4783 are not critical to your caching system. If you use
4784 redirectors for access control, and you enable this option,
4785 users may have access to pages they should not
4786 be allowed to request.
4789 NAME: url_rewrite_extras
4790 TYPE: TokenOrQuotedString
4791 LOC: Config.redirector_extras
4792 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
4794 Specifies a string to be append to request line format for the
4795 rewriter helper. "Quoted" format values may contain spaces and
4796 logformat %macros. In theory, any logformat %macro can be used.
4797 In practice, a %macro expands as a dash (-) if the helper request is
4798 sent before the required macro information is available to Squid.
4802 OPTIONS FOR STORE ID
4803 -----------------------------------------------------------------------------
4806 NAME: store_id_program storeurl_rewrite_program
4808 LOC: Config.Program.store_id
4811 Specify the location of the executable StoreID helper to use.
4812 Since they can perform almost any function there isn't one included.
4814 For each requested URL, the helper will receive one line with the format
4816 [channel-ID <SP>] URL [<SP> extras]<NL>
4819 After processing the request the helper must reply using the following format:
4821 [channel-ID <SP>] result [<SP> kv-pairs]
4823 The result code can be:
4826 Use the StoreID supplied in 'store-id='.
4829 The default is to use HTTP request URL as the store ID.
4832 An internal error occured in the helper, preventing
4833 a result being identified.
4836 Helper programs should be prepared to receive and possibly ignore
4837 additional whitespace-separated tokens on each input line.
4839 When using the concurrency= option the protocol is changed by
4840 introducing a query channel tag in front of the request/response.
4841 The query channel tag is a number between 0 and concurrency-1.
4842 This value must be echoed back unchanged to Squid as the first part
4843 of the response relating to its request.
4845 NOTE: when using StoreID refresh_pattern will apply to the StoreID
4846 returned from the helper and not the URL.
4848 WARNING: Wrong StoreID value returned by a careless helper may result
4849 in the wrong cached response returned to the user.
4851 By default, a StoreID helper is not used.
4854 NAME: store_id_extras
4855 TYPE: TokenOrQuotedString
4856 LOC: Config.storeId_extras
4857 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
4859 Specifies a string to be append to request line format for the
4860 StoreId helper. "Quoted" format values may contain spaces and
4861 logformat %macros. In theory, any logformat %macro can be used.
4862 In practice, a %macro expands as a dash (-) if the helper request is
4863 sent before the required macro information is available to Squid.
4866 NAME: store_id_children storeurl_rewrite_children
4867 TYPE: HelperChildConfig
4868 DEFAULT: 20 startup=0 idle=1 concurrency=0
4869 LOC: Config.storeIdChildren
4871 The maximum number of StoreID helper processes to spawn. If you limit
4872 it too few Squid will have to wait for them to process a backlog of
4873 requests, slowing it down. If you allow too many they will use RAM
4874 and other system resources noticably.
4876 The startup= and idle= options allow some measure of skew in your
4881 Sets a minimum of how many processes are to be spawned when Squid
4882 starts or reconfigures. When set to zero the first request will
4883 cause spawning of the first child process to handle it.
4885 Starting too few will cause an initial slowdown in traffic as Squid
4886 attempts to simultaneously spawn enough processes to cope.
4890 Sets a minimum of how many processes Squid is to try and keep available
4891 at all times. When traffic begins to rise above what the existing
4892 processes can handle this many more will be spawned up to the maximum
4893 configured. A minimum setting of 1 is required.
4897 The number of requests each storeID helper can handle in
4898 parallel. Defaults to 0 which indicates the helper
4899 is a old-style single threaded program.
4901 When this directive is set to a value >= 1 then the protocol
4902 used to communicate with the helper is modified to include
4903 an ID in front of the request/response. The ID from the request
4904 must be echoed back with the response to that request.
4907 NAME: store_id_access storeurl_rewrite_access
4910 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4911 LOC: Config.accessList.store_id
4913 If defined, this access list specifies which requests are
4914 sent to the StoreID processes. By default all requests
4917 This clause supports both fast and slow acl types.
4918 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4921 NAME: store_id_bypass storeurl_rewrite_bypass
4923 LOC: Config.onoff.store_id_bypass
4926 When this is 'on', a request will not go through the
4927 helper if all helpers are busy. If this is 'off'
4928 and the helper queue grows too large, Squid will exit
4929 with a FATAL error and ask you to increase the number of
4930 helpers. You should only enable this if the helperss
4931 are not critical to your caching system. If you use
4932 helpers for critical caching components, and you enable this
4933 option, users may not get objects from cache.
4937 OPTIONS FOR TUNING THE CACHE
4938 -----------------------------------------------------------------------------
4941 NAME: cache no_cache
4944 DEFAULT_DOC: By default, this directive is unused and has no effect.
4945 LOC: Config.accessList.noCache
4947 Requests denied by this directive will not be served from the cache
4948 and their responses will not be stored in the cache. This directive
4949 has no effect on other transactions and on already cached responses.
4951 This clause supports both fast and slow acl types.
4952 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4954 This and the two other similar caching directives listed below are
4955 checked at different transaction processing stages, have different
4956 access to response information, affect different cache operations,
4957 and differ in slow ACLs support:
4959 * cache: Checked before Squid makes a hit/miss determination.
4960 No access to reply information!
4961 Denies both serving a hit and storing a miss.
4962 Supports both fast and slow ACLs.
4963 * send_hit: Checked after a hit was detected.
4964 Has access to reply (hit) information.
4965 Denies serving a hit only.
4966 Supports fast ACLs only.
4967 * store_miss: Checked before storing a cachable miss.
4968 Has access to reply (miss) information.
4969 Denies storing a miss only.
4970 Supports fast ACLs only.
4972 If you are not sure which of the three directives to use, apply the
4973 following decision logic:
4975 * If your ACL(s) are of slow type _and_ need response info, redesign.
4976 Squid does not support that particular combination at this time.
4978 * If your directive ACL(s) are of slow type, use "cache"; and/or
4979 * if your directive ACL(s) need no response info, use "cache".
4981 * If you do not want the response cached, use store_miss; and/or
4982 * if you do not want a hit on a cached response, use send_hit.
4988 DEFAULT_DOC: By default, this directive is unused and has no effect.
4989 LOC: Config.accessList.sendHit
4991 Responses denied by this directive will not be served from the cache
4992 (but may still be cached, see store_miss). This directive has no
4993 effect on the responses it allows and on the cached objects.
4995 Please see the "cache" directive for a summary of differences among
4996 store_miss, send_hit, and cache directives.
4998 Unlike the "cache" directive, send_hit only supports fast acl
4999 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5003 # apply custom Store ID mapping to some URLs
5004 acl MapMe dstdomain .c.example.com
5005 store_id_program ...
5006 store_id_access allow MapMe
5008 # but prevent caching of special responses
5009 # such as 302 redirects that cause StoreID loops
5010 acl Ordinary http_status 200-299
5011 store_miss deny MapMe !Ordinary
5013 # and do not serve any previously stored special responses
5014 # from the cache (in case they were already cached before
5015 # the above store_miss rule was in effect).
5016 send_hit deny MapMe !Ordinary
5022 DEFAULT_DOC: By default, this directive is unused and has no effect.
5023 LOC: Config.accessList.storeMiss
5025 Responses denied by this directive will not be cached (but may still
5026 be served from the cache, see send_hit). This directive has no
5027 effect on the responses it allows and on the already cached responses.
5029 Please see the "cache" directive for a summary of differences among
5030 store_miss, send_hit, and cache directives. See the
5031 send_hit directive for a usage example.
5033 Unlike the "cache" directive, store_miss only supports fast acl
5034 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5040 LOC: Config.maxStale
5043 This option puts an upper limit on how stale content Squid
5044 will serve from the cache if cache validation fails.
5045 Can be overriden by the refresh_pattern max-stale option.
5048 NAME: refresh_pattern
5049 TYPE: refreshpattern
5053 usage: refresh_pattern [-i] regex min percent max [options]
5055 By default, regular expressions are CASE-SENSITIVE. To make
5056 them case-insensitive, use the -i option.
5058 'Min' is the time (in minutes) an object without an explicit
5059 expiry time should be considered fresh. The recommended
5060 value is 0, any higher values may cause dynamic applications
5061 to be erroneously cached unless the application designer
5062 has taken the appropriate actions.
5064 'Percent' is a percentage of the objects age (time since last
5065 modification age) an object without explicit expiry time
5066 will be considered fresh.
5068 'Max' is an upper limit on how long objects without an explicit
5069 expiry time will be considered fresh.
5071 options: override-expire
5076 ignore-must-revalidate
5083 override-expire enforces min age even if the server
5084 sent an explicit expiry time (e.g., with the
5085 Expires: header or Cache-Control: max-age). Doing this
5086 VIOLATES the HTTP standard. Enabling this feature
5087 could make you liable for problems which it causes.
5089 Note: override-expire does not enforce staleness - it only extends
5090 freshness / min. If the server returns a Expires time which
5091 is longer than your max time, Squid will still consider
5092 the object fresh for that period of time.
5094 override-lastmod enforces min age even on objects
5095 that were modified recently.
5097 reload-into-ims changes a client no-cache or ``reload''
5098 request for a cached entry into a conditional request using
5099 If-Modified-Since and/or If-None-Match headers, provided the
5100 cached entry has a Last-Modified and/or a strong ETag header.
5101 Doing this VIOLATES the HTTP standard. Enabling this feature
5102 could make you liable for problems which it causes.
5104 ignore-reload ignores a client no-cache or ``reload''
5105 header. Doing this VIOLATES the HTTP standard. Enabling
5106 this feature could make you liable for problems which
5109 ignore-no-store ignores any ``Cache-control: no-store''
5110 headers received from a server. Doing this VIOLATES
5111 the HTTP standard. Enabling this feature could make you
5112 liable for problems which it causes.
5114 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
5115 headers received from a server. Doing this VIOLATES
5116 the HTTP standard. Enabling this feature could make you
5117 liable for problems which it causes.
5119 ignore-private ignores any ``Cache-control: private''
5120 headers received from a server. Doing this VIOLATES
5121 the HTTP standard. Enabling this feature could make you
5122 liable for problems which it causes.
5124 ignore-auth caches responses to requests with authorization,
5125 as if the originserver had sent ``Cache-control: public''
5126 in the response header. Doing this VIOLATES the HTTP standard.
5127 Enabling this feature could make you liable for problems which
5130 refresh-ims causes squid to contact the origin server
5131 when a client issues an If-Modified-Since request. This
5132 ensures that the client will receive an updated version
5133 if one is available.
5135 store-stale stores responses even if they don't have explicit
5136 freshness or a validator (i.e., Last-Modified or an ETag)
5137 present, or if they're already stale. By default, Squid will
5138 not cache such responses because they usually can't be
5139 reused. Note that such responses will be stale by default.
5141 max-stale=NN provide a maximum staleness factor. Squid won't
5142 serve objects more stale than this even if it failed to
5143 validate the object. Default: use the max_stale global limit.
5145 Basically a cached object is:
5147 FRESH if expires < now, else STALE
5149 FRESH if lm-factor < percent, else STALE
5153 The refresh_pattern lines are checked in the order listed here.
5154 The first entry which matches is used. If none of the entries
5155 match the default will be used.
5157 Note, you must uncomment all the default lines if you want
5158 to change one. The default setting is only active if none is
5164 # Add any of your own refresh_pattern entries above these.
5166 refresh_pattern ^ftp: 1440 20% 10080
5167 refresh_pattern ^gopher: 1440 0% 1440
5168 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5169 refresh_pattern . 0 20% 4320
5173 NAME: quick_abort_min
5177 LOC: Config.quickAbort.min
5180 NAME: quick_abort_max
5184 LOC: Config.quickAbort.max
5187 NAME: quick_abort_pct
5191 LOC: Config.quickAbort.pct
5193 The cache by default continues downloading aborted requests
5194 which are almost completed (less than 16 KB remaining). This
5195 may be undesirable on slow (e.g. SLIP) links and/or very busy
5196 caches. Impatient users may tie up file descriptors and
5197 bandwidth by repeatedly requesting and immediately aborting
5200 When the user aborts a request, Squid will check the
5201 quick_abort values to the amount of data transfered until
5204 If the transfer has less than 'quick_abort_min' KB remaining,
5205 it will finish the retrieval.
5207 If the transfer has more than 'quick_abort_max' KB remaining,
5208 it will abort the retrieval.
5210 If more than 'quick_abort_pct' of the transfer has completed,
5211 it will finish the retrieval.
5213 If you do not want any retrieval to continue after the client
5214 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5217 If you want retrievals to always continue if they are being
5218 cached set 'quick_abort_min' to '-1 KB'.
5221 NAME: read_ahead_gap
5222 COMMENT: buffer-size
5224 LOC: Config.readAheadGap
5227 The amount of data the cache will buffer ahead of what has been
5228 sent to the client when retrieving an object from another server.
5232 IFDEF: USE_HTTP_VIOLATIONS
5235 LOC: Config.negativeTtl
5238 Set the Default Time-to-Live (TTL) for failed requests.
5239 Certain types of failures (such as "connection refused" and
5240 "404 Not Found") are able to be negatively-cached for a short time.
5241 Modern web servers should provide Expires: header, however if they
5242 do not this can provide a minimum TTL.
5243 The default is not to cache errors with unknown expiry details.
5245 Note that this is different from negative caching of DNS lookups.
5247 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5248 this feature could make you liable for problems which it
5252 NAME: positive_dns_ttl
5255 LOC: Config.positiveDnsTtl
5258 Upper limit on how long Squid will cache positive DNS responses.
5259 Default is 6 hours (360 minutes). This directive must be set
5260 larger than negative_dns_ttl.
5263 NAME: negative_dns_ttl
5266 LOC: Config.negativeDnsTtl
5269 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5270 This also sets the lower cache limit on positive lookups.
5271 Minimum value is 1 second, and it is not recommendable to go
5272 much below 10 seconds.
5275 NAME: range_offset_limit
5276 COMMENT: size [acl acl...]
5278 LOC: Config.rangeOffsetLimit
5281 usage: (size) [units] [[!]aclname]
5283 Sets an upper limit on how far (number of bytes) into the file
5284 a Range request may be to cause Squid to prefetch the whole file.
5285 If beyond this limit, Squid forwards the Range request as it is and
5286 the result is NOT cached.
5288 This is to stop a far ahead range request (lets say start at 17MB)
5289 from making Squid fetch the whole object up to that point before
5290 sending anything to the client.
5292 Multiple range_offset_limit lines may be specified, and they will
5293 be searched from top to bottom on each request until a match is found.
5294 The first match found will be used. If no line matches a request, the
5295 default limit of 0 bytes will be used.
5297 'size' is the limit specified as a number of units.
5299 'units' specifies whether to use bytes, KB, MB, etc.
5300 If no units are specified bytes are assumed.
5302 A size of 0 causes Squid to never fetch more than the
5303 client requested. (default)
5305 A size of 'none' causes Squid to always fetch the object from the
5306 beginning so it may cache the result. (2.0 style)
5308 'aclname' is the name of a defined ACL.
5310 NP: Using 'none' as the byte value here will override any quick_abort settings
5311 that may otherwise apply to the range request. The range request will
5312 be fully fetched from start to finish regardless of the client
5313 actions. This affects bandwidth usage.
5316 NAME: minimum_expiry_time
5319 LOC: Config.minimum_expiry_time
5322 The minimum caching time according to (Expires - Date)
5323 headers Squid honors if the object can't be revalidated.
5324 The default is 60 seconds.
5326 In reverse proxy environments it might be desirable to honor
5327 shorter object lifetimes. It is most likely better to make
5328 your server return a meaningful Last-Modified header however.
5330 In ESI environments where page fragments often have short
5331 lifetimes, this will often be best set to 0.
5334 NAME: store_avg_object_size
5338 LOC: Config.Store.avgObjectSize
5340 Average object size, used to estimate number of objects your
5341 cache can hold. The default is 13 KB.
5343 This is used to pre-seed the cache index memory allocation to
5344 reduce expensive reallocate operations while handling clients
5345 traffic. Too-large values may result in memory allocation during
5346 peak traffic, too-small values will result in wasted memory.
5348 Check the cache manager 'info' report metrics for the real
5349 object sizes seen by your Squid before tuning this.
5352 NAME: store_objects_per_bucket
5355 LOC: Config.Store.objectsPerBucket
5357 Target number of objects per bucket in the store hash table.
5358 Lowering this value increases the total number of buckets and
5359 also the storage maintenance rate. The default is 20.
5364 -----------------------------------------------------------------------------
5367 NAME: request_header_max_size
5371 LOC: Config.maxRequestHeaderSize
5373 This specifies the maximum size for HTTP headers in a request.
5374 Request headers are usually relatively small (about 512 bytes).
5375 Placing a limit on the request header size will catch certain
5376 bugs (for example with persistent connections) and possibly
5377 buffer-overflow or denial-of-service attacks.
5380 NAME: reply_header_max_size
5384 LOC: Config.maxReplyHeaderSize
5386 This specifies the maximum size for HTTP headers in a reply.
5387 Reply headers are usually relatively small (about 512 bytes).
5388 Placing a limit on the reply header size will catch certain
5389 bugs (for example with persistent connections) and possibly
5390 buffer-overflow or denial-of-service attacks.
5393 NAME: request_body_max_size
5397 DEFAULT_DOC: No limit.
5398 LOC: Config.maxRequestBodySize
5400 This specifies the maximum size for an HTTP request body.
5401 In other words, the maximum size of a PUT/POST request.
5402 A user who attempts to send a request with a body larger
5403 than this limit receives an "Invalid Request" error message.
5404 If you set this parameter to a zero (the default), there will
5405 be no limit imposed.
5407 See also client_request_buffer_max_size for an alternative
5408 limitation on client uploads which can be configured.
5411 NAME: client_request_buffer_max_size
5415 LOC: Config.maxRequestBufferSize
5417 This specifies the maximum buffer size of a client request.
5418 It prevents squid eating too much memory when somebody uploads
5422 NAME: chunked_request_body_max_size
5426 LOC: Config.maxChunkedRequestBodySize
5428 A broken or confused HTTP/1.1 client may send a chunked HTTP
5429 request to Squid. Squid does not have full support for that
5430 feature yet. To cope with such requests, Squid buffers the
5431 entire request and then dechunks request body to create a
5432 plain HTTP/1.0 request with a known content length. The plain
5433 request is then used by the rest of Squid code as usual.
5435 The option value specifies the maximum size of the buffer used
5436 to hold the request before the conversion. If the chunked
5437 request size exceeds the specified limit, the conversion
5438 fails, and the client receives an "unsupported request" error,
5439 as if dechunking was disabled.
5441 Dechunking is enabled by default. To disable conversion of
5442 chunked requests, set the maximum to zero.
5444 Request dechunking feature and this option in particular are a
5445 temporary hack. When chunking requests and responses are fully
5446 supported, there will be no need to buffer a chunked request.
5450 IFDEF: USE_HTTP_VIOLATIONS
5453 DEFAULT_DOC: Obey RFC 2616.
5454 LOC: Config.accessList.brokenPosts
5456 A list of ACL elements which, if matched, causes Squid to send
5457 an extra CRLF pair after the body of a PUT/POST request.
5459 Some HTTP servers has broken implementations of PUT/POST,
5460 and rely on an extra CRLF pair sent by some WWW clients.
5462 Quote from RFC2616 section 4.1 on this matter:
5464 Note: certain buggy HTTP/1.0 client implementations generate an
5465 extra CRLF's after a POST request. To restate what is explicitly
5466 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5467 a request with an extra CRLF.
5469 This clause only supports fast acl types.
5470 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5473 acl buggy_server url_regex ^http://....
5474 broken_posts allow buggy_server
5477 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5480 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5482 LOC: Adaptation::Config::use_indirect_client
5484 Controls whether the indirect client IP address (instead of the direct
5485 client IP address) is passed to adaptation services.
5487 See also: follow_x_forwarded_for adaptation_send_client_ip
5491 IFDEF: USE_HTTP_VIOLATIONS
5495 LOC: Config.onoff.via
5497 If set (default), Squid will include a Via header in requests and
5498 replies as required by RFC2616.
5504 LOC: Config.onoff.ie_refresh
5507 Microsoft Internet Explorer up until version 5.5 Service
5508 Pack 1 has an issue with transparent proxies, wherein it
5509 is impossible to force a refresh. Turning this on provides
5510 a partial fix to the problem, by causing all IMS-REFRESH
5511 requests from older IE versions to check the origin server
5512 for fresh content. This reduces hit ratio by some amount
5513 (~10% in my experience), but allows users to actually get
5514 fresh content when they want it. Note because Squid
5515 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5516 of 5.5 is unchanged from old versions of Squid (i.e. a
5517 forced refresh is impossible). Newer versions of IE will,
5518 hopefully, continue to have the new behavior and will be
5519 handled based on that assumption. This option defaults to
5520 the old Squid behavior, which is better for hit ratios but
5521 worse for clients using IE, if they need to be able to
5522 force fresh content.
5525 NAME: vary_ignore_expire
5528 LOC: Config.onoff.vary_ignore_expire
5531 Many HTTP servers supporting Vary gives such objects
5532 immediate expiry time with no cache-control header
5533 when requested by a HTTP/1.0 client. This option
5534 enables Squid to ignore such expiry times until
5535 HTTP/1.1 is fully implemented.
5537 WARNING: If turned on this may eventually cause some
5538 varying objects not intended for caching to get cached.
5541 NAME: request_entities
5543 LOC: Config.onoff.request_entities
5546 Squid defaults to deny GET and HEAD requests with request entities,
5547 as the meaning of such requests are undefined in the HTTP standard
5548 even if not explicitly forbidden.
5550 Set this directive to on if you have clients which insists
5551 on sending request entities in GET or HEAD requests. But be warned
5552 that there is server software (both proxies and web servers) which
5553 can fail to properly process this kind of request which may make you
5554 vulnerable to cache pollution attacks if enabled.
5557 NAME: request_header_access
5558 IFDEF: USE_HTTP_VIOLATIONS
5559 TYPE: http_header_access
5560 LOC: Config.request_header_access
5562 DEFAULT_DOC: No limits.
5564 Usage: request_header_access header_name allow|deny [!]aclname ...
5566 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5567 this feature could make you liable for problems which it
5570 This option replaces the old 'anonymize_headers' and the
5571 older 'http_anonymizer' option with something that is much
5572 more configurable. A list of ACLs for each header name allows
5573 removal of specific header fields under specific conditions.
5575 This option only applies to outgoing HTTP request headers (i.e.,
5576 headers sent by Squid to the next HTTP hop such as a cache peer
5577 or an origin server). The option has no effect during cache hit
5578 detection. The equivalent adaptation vectoring point in ICAP
5579 terminology is post-cache REQMOD.
5581 The option is applied to individual outgoing request header
5582 fields. For each request header field F, Squid uses the first
5583 qualifying sets of request_header_access rules:
5585 1. Rules with header_name equal to F's name.
5586 2. Rules with header_name 'Other', provided F's name is not
5587 on the hard-coded list of commonly used HTTP header names.
5588 3. Rules with header_name 'All'.
5590 Within that qualifying rule set, rule ACLs are checked as usual.
5591 If ACLs of an "allow" rule match, the header field is allowed to
5592 go through as is. If ACLs of a "deny" rule match, the header is
5593 removed and request_header_replace is then checked to identify
5594 if the removed header has a replacement. If no rules within the
5595 set have matching ACLs, the header field is left as is.
5597 For example, to achieve the same behavior as the old
5598 'http_anonymizer standard' option, you should use:
5600 request_header_access From deny all
5601 request_header_access Referer deny all
5602 request_header_access User-Agent deny all
5604 Or, to reproduce the old 'http_anonymizer paranoid' feature
5607 request_header_access Authorization allow all
5608 request_header_access Proxy-Authorization allow all
5609 request_header_access Cache-Control allow all
5610 request_header_access Content-Length allow all
5611 request_header_access Content-Type allow all
5612 request_header_access Date allow all
5613 request_header_access Host allow all
5614 request_header_access If-Modified-Since allow all
5615 request_header_access Pragma allow all
5616 request_header_access Accept allow all
5617 request_header_access Accept-Charset allow all
5618 request_header_access Accept-Encoding allow all
5619 request_header_access Accept-Language allow all
5620 request_header_access Connection allow all
5621 request_header_access All deny all
5623 HTTP reply headers are controlled with the reply_header_access directive.
5625 By default, all headers are allowed (no anonymizing is performed).
5628 NAME: reply_header_access
5629 IFDEF: USE_HTTP_VIOLATIONS
5630 TYPE: http_header_access
5631 LOC: Config.reply_header_access
5633 DEFAULT_DOC: No limits.
5635 Usage: reply_header_access header_name allow|deny [!]aclname ...
5637 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5638 this feature could make you liable for problems which it
5641 This option only applies to reply headers, i.e., from the
5642 server to the client.
5644 This is the same as request_header_access, but in the other
5645 direction. Please see request_header_access for detailed
5648 For example, to achieve the same behavior as the old
5649 'http_anonymizer standard' option, you should use:
5651 reply_header_access Server deny all
5652 reply_header_access WWW-Authenticate deny all
5653 reply_header_access Link deny all
5655 Or, to reproduce the old 'http_anonymizer paranoid' feature
5658 reply_header_access Allow allow all
5659 reply_header_access WWW-Authenticate allow all
5660 reply_header_access Proxy-Authenticate allow all
5661 reply_header_access Cache-Control allow all
5662 reply_header_access Content-Encoding allow all
5663 reply_header_access Content-Length allow all
5664 reply_header_access Content-Type allow all
5665 reply_header_access Date allow all
5666 reply_header_access Expires allow all
5667 reply_header_access Last-Modified allow all
5668 reply_header_access Location allow all
5669 reply_header_access Pragma allow all
5670 reply_header_access Content-Language allow all
5671 reply_header_access Retry-After allow all
5672 reply_header_access Title allow all
5673 reply_header_access Content-Disposition allow all
5674 reply_header_access Connection allow all
5675 reply_header_access All deny all
5677 HTTP request headers are controlled with the request_header_access directive.
5679 By default, all headers are allowed (no anonymizing is
5683 NAME: request_header_replace header_replace
5684 IFDEF: USE_HTTP_VIOLATIONS
5685 TYPE: http_header_replace
5686 LOC: Config.request_header_access
5689 Usage: request_header_replace header_name message
5690 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
5692 This option allows you to change the contents of headers
5693 denied with request_header_access above, by replacing them
5694 with some fixed string.
5696 This only applies to request headers, not reply headers.
5698 By default, headers are removed if denied.
5701 NAME: reply_header_replace
5702 IFDEF: USE_HTTP_VIOLATIONS
5703 TYPE: http_header_replace
5704 LOC: Config.reply_header_access
5707 Usage: reply_header_replace header_name message
5708 Example: reply_header_replace Server Foo/1.0
5710 This option allows you to change the contents of headers
5711 denied with reply_header_access above, by replacing them
5712 with some fixed string.
5714 This only applies to reply headers, not request headers.
5716 By default, headers are removed if denied.
5719 NAME: request_header_add
5720 TYPE: HeaderWithAclList
5721 LOC: Config.request_header_add
5724 Usage: request_header_add field-name field-value acl1 [acl2] ...
5725 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
5727 This option adds header fields to outgoing HTTP requests (i.e.,
5728 request headers sent by Squid to the next HTTP hop such as a
5729 cache peer or an origin server). The option has no effect during
5730 cache hit detection. The equivalent adaptation vectoring point
5731 in ICAP terminology is post-cache REQMOD.
5733 Field-name is a token specifying an HTTP header name. If a
5734 standard HTTP header name is used, Squid does not check whether
5735 the new header conflicts with any existing headers or violates
5736 HTTP rules. If the request to be modified already contains a
5737 field with the same name, the old field is preserved but the
5738 header field values are not merged.
5740 Field-value is either a token or a quoted string. If quoted
5741 string format is used, then the surrounding quotes are removed
5742 while escape sequences and %macros are processed.
5744 In theory, all of the logformat codes can be used as %macros.
5745 However, unlike logging (which happens at the very end of
5746 transaction lifetime), the transaction may not yet have enough
5747 information to expand a macro when the new header value is needed.
5748 And some information may already be available to Squid but not yet
5749 committed where the macro expansion code can access it (report
5750 such instances!). The macro will be expanded into a single dash
5751 ('-') in such cases. Not all macros have been tested.
5753 One or more Squid ACLs may be specified to restrict header
5754 injection to matching requests. As always in squid.conf, all
5755 ACLs in an option ACL list must be satisfied for the insertion
5756 to happen. The request_header_add option supports fast ACLs
5765 This option used to log custom information about the master
5766 transaction. For example, an admin may configure Squid to log
5767 which "user group" the transaction belongs to, where "user group"
5768 will be determined based on a set of ACLs and not [just]
5769 authentication information.
5770 Values of key/value pairs can be logged using %{key}note macros:
5772 note key value acl ...
5773 logformat myFormat ... %{key}note ...
5776 NAME: relaxed_header_parser
5777 COMMENT: on|off|warn
5779 LOC: Config.onoff.relaxed_header_parser
5782 In the default "on" setting Squid accepts certain forms
5783 of non-compliant HTTP messages where it is unambiguous
5784 what the sending application intended even if the message
5785 is not correctly formatted. The messages is then normalized
5786 to the correct form when forwarded by Squid.
5788 If set to "warn" then a warning will be emitted in cache.log
5789 each time such HTTP error is encountered.
5791 If set to "off" then such HTTP errors will cause the request
5792 or response to be rejected.
5795 NAME: collapsed_forwarding
5798 LOC: Config.onoff.collapsed_forwarding
5801 This option controls whether Squid is allowed to merge multiple
5802 potentially cachable requests for the same URI before Squid knows
5803 whether the response is going to be cachable.
5805 This feature is disabled by default: Enabling collapsed forwarding
5806 needlessly delays forwarding requests that look cachable (when they are
5807 collapsed) but then need to be forwarded individually anyway because
5808 they end up being for uncachable content. However, in some cases, such
5809 as accelleration of highly cachable content with periodic or groupped
5810 expiration times, the gains from collapsing [large volumes of
5811 simultenous refresh requests] outweigh losses from such delays.
5816 -----------------------------------------------------------------------------
5819 NAME: forward_timeout
5822 LOC: Config.Timeout.forward
5825 This parameter specifies how long Squid should at most attempt in
5826 finding a forwarding path for the request before giving up.
5829 NAME: connect_timeout
5832 LOC: Config.Timeout.connect
5835 This parameter specifies how long to wait for the TCP connect to
5836 the requested server or peer to complete before Squid should
5837 attempt to find another path where to forward the request.
5840 NAME: peer_connect_timeout
5843 LOC: Config.Timeout.peer_connect
5846 This parameter specifies how long to wait for a pending TCP
5847 connection to a peer cache. The default is 30 seconds. You
5848 may also set different timeout values for individual neighbors
5849 with the 'connect-timeout' option on a 'cache_peer' line.
5855 LOC: Config.Timeout.read
5858 The read_timeout is applied on server-side connections. After
5859 each successful read(), the timeout will be extended by this
5860 amount. If no data is read again after this amount of time,
5861 the request is aborted and logged with ERR_READ_TIMEOUT. The
5862 default is 15 minutes.
5868 LOC: Config.Timeout.write
5871 This timeout is tracked for all connections that have data
5872 available for writing and are waiting for the socket to become
5873 ready. After each successful write, the timeout is extended by
5874 the configured amount. If Squid has data to write but the
5875 connection is not ready for the configured duration, the
5876 transaction associated with the connection is terminated. The
5877 default is 15 minutes.
5880 NAME: request_timeout
5882 LOC: Config.Timeout.request
5885 How long to wait for complete HTTP request headers after initial
5886 connection establishment.
5889 NAME: client_idle_pconn_timeout persistent_request_timeout
5891 LOC: Config.Timeout.clientIdlePconn
5894 How long to wait for the next HTTP request on a persistent
5895 client connection after the previous request completes.
5898 NAME: ftp_client_idle_timeout
5900 LOC: Config.Timeout.ftpClientIdle
5903 How long to wait for an FTP request on a connection to Squid ftp_port.
5904 Many FTP clients do not deal with idle connection closures well,
5905 necessitating a longer default timeout than client_idle_pconn_timeout
5906 used for incoming HTTP requests.
5909 NAME: client_lifetime
5912 LOC: Config.Timeout.lifetime
5915 The maximum amount of time a client (browser) is allowed to
5916 remain connected to the cache process. This protects the Cache
5917 from having a lot of sockets (and hence file descriptors) tied up
5918 in a CLOSE_WAIT state from remote clients that go away without
5919 properly shutting down (either because of a network failure or
5920 because of a poor client implementation). The default is one
5923 NOTE: The default value is intended to be much larger than any
5924 client would ever need to be connected to your cache. You
5925 should probably change client_lifetime only as a last resort.
5926 If you seem to have many client connections tying up
5927 filedescriptors, we recommend first tuning the read_timeout,
5928 request_timeout, persistent_request_timeout and quick_abort values.
5931 NAME: half_closed_clients
5933 LOC: Config.onoff.half_closed_clients
5936 Some clients may shutdown the sending side of their TCP
5937 connections, while leaving their receiving sides open. Sometimes,
5938 Squid can not tell the difference between a half-closed and a
5939 fully-closed TCP connection.
5941 By default, Squid will immediately close client connections when
5942 read(2) returns "no more data to read."
5944 Change this option to 'on' and Squid will keep open connections
5945 until a read(2) or write(2) on the socket returns an error.
5946 This may show some benefits for reverse proxies. But if not
5947 it is recommended to leave OFF.
5950 NAME: server_idle_pconn_timeout pconn_timeout
5952 LOC: Config.Timeout.serverIdlePconn
5955 Timeout for idle persistent connections to servers and other
5962 LOC: Ident::TheConfig.timeout
5965 Maximum time to wait for IDENT lookups to complete.
5967 If this is too high, and you enabled IDENT lookups from untrusted
5968 users, you might be susceptible to denial-of-service by having
5969 many ident requests going at once.
5972 NAME: shutdown_lifetime
5975 LOC: Config.shutdownLifetime
5978 When SIGTERM or SIGHUP is received, the cache is put into
5979 "shutdown pending" mode until all active sockets are closed.
5980 This value is the lifetime to set for all open descriptors
5981 during shutdown mode. Any active clients after this many
5982 seconds will receive a 'timeout' message.
5986 ADMINISTRATIVE PARAMETERS
5987 -----------------------------------------------------------------------------
5993 LOC: Config.adminEmail
5995 Email-address of local cache manager who will receive
5996 mail if the cache dies. The default is "webmaster".
6002 LOC: Config.EmailFrom
6004 From: email-address for mail sent when the cache dies.
6005 The default is to use 'squid@unique_hostname'.
6007 See also: unique_hostname directive.
6013 LOC: Config.EmailProgram
6015 Email program used to send mail if the cache dies.
6016 The default is "mail". The specified program must comply
6017 with the standard Unix mail syntax:
6018 mail-program recipient < mailfile
6020 Optional command line options can be specified.
6023 NAME: cache_effective_user
6025 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
6026 LOC: Config.effectiveUser
6028 If you start Squid as root, it will change its effective/real
6029 UID/GID to the user specified below. The default is to change
6030 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
6031 see also; cache_effective_group
6034 NAME: cache_effective_group
6037 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
6038 LOC: Config.effectiveGroup
6040 Squid sets the GID to the effective user's default group ID
6041 (taken from the password file) and supplementary group list
6042 from the groups membership.
6044 If you want Squid to run with a specific GID regardless of
6045 the group memberships of the effective user then set this
6046 to the group (or GID) you want Squid to run as. When set
6047 all other group privileges of the effective user are ignored
6048 and only this GID is effective. If Squid is not started as
6049 root the user starting Squid MUST be member of the specified
6052 This option is not recommended by the Squid Team.
6053 Our preference is for administrators to configure a secure
6054 user account for squid with UID/GID matching system policies.
6057 NAME: httpd_suppress_version_string
6061 LOC: Config.onoff.httpd_suppress_version_string
6063 Suppress Squid version string info in HTTP headers and HTML error pages.
6066 NAME: visible_hostname
6068 LOC: Config.visibleHostname
6070 DEFAULT_DOC: Automatically detect the system host name
6072 If you want to present a special hostname in error messages, etc,
6073 define this. Otherwise, the return value of gethostname()
6074 will be used. If you have multiple caches in a cluster and
6075 get errors about IP-forwarding you must set them to have individual
6076 names with this setting.
6079 NAME: unique_hostname
6081 LOC: Config.uniqueHostname
6083 DEFAULT_DOC: Copy the value from visible_hostname
6085 If you want to have multiple machines with the same
6086 'visible_hostname' you must give each machine a different
6087 'unique_hostname' so forwarding loops can be detected.
6090 NAME: hostname_aliases
6092 LOC: Config.hostnameAliases
6095 A list of other DNS names your cache has.
6103 Minimum umask which should be enforced while the proxy
6104 is running, in addition to the umask set at startup.
6106 For a traditional octal representation of umasks, start
6111 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6112 -----------------------------------------------------------------------------
6114 This section contains parameters for the (optional) cache
6115 announcement service. This service is provided to help
6116 cache administrators locate one another in order to join or
6117 create cache hierarchies.
6119 An 'announcement' message is sent (via UDP) to the registration
6120 service by Squid. By default, the announcement message is NOT
6121 SENT unless you enable it with 'announce_period' below.
6123 The announcement message includes your hostname, plus the
6124 following information from this configuration file:
6130 All current information is processed regularly and made
6131 available on the Web at http://www.ircache.net/Cache/Tracker/.
6134 NAME: announce_period
6136 LOC: Config.Announce.period
6138 DEFAULT_DOC: Announcement messages disabled.
6140 This is how frequently to send cache announcements.
6142 To enable announcing your cache, just set an announce period.
6145 announce_period 1 day
6150 DEFAULT: tracker.ircache.net
6151 LOC: Config.Announce.host
6153 Set the hostname where announce registration messages will be sent.
6155 See also announce_port and announce_file
6161 LOC: Config.Announce.file
6163 The contents of this file will be included in the announce
6164 registration messages.
6170 LOC: Config.Announce.port
6172 Set the port where announce registration messages will be sent.
6174 See also announce_host and announce_file
6178 HTTPD-ACCELERATOR OPTIONS
6179 -----------------------------------------------------------------------------
6182 NAME: httpd_accel_surrogate_id
6185 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
6186 LOC: Config.Accel.surrogate_id
6188 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
6189 need an identification token to allow control targeting. Because
6190 a farm of surrogates may all perform the same tasks, they may share
6191 an identification token.
6194 NAME: http_accel_surrogate_remote
6198 LOC: Config.onoff.surrogate_is_remote
6200 Remote surrogates (such as those in a CDN) honour the header
6201 "Surrogate-Control: no-store-remote".
6203 Set this to on to have squid behave as a remote surrogate.
6207 IFDEF: USE_SQUID_ESI
6208 COMMENT: libxml2|expat|custom
6210 LOC: ESIParser::Type
6213 ESI markup is not strictly XML compatible. The custom ESI parser
6214 will give higher performance, but cannot handle non ASCII character
6219 DELAY POOL PARAMETERS
6220 -----------------------------------------------------------------------------
6224 TYPE: delay_pool_count
6226 IFDEF: USE_DELAY_POOLS
6229 This represents the number of delay pools to be used. For example,
6230 if you have one class 2 delay pool and one class 3 delays pool, you
6231 have a total of 2 delay pools.
6233 See also delay_parameters, delay_class, delay_access for pool
6234 configuration details.
6238 TYPE: delay_pool_class
6240 IFDEF: USE_DELAY_POOLS
6243 This defines the class of each delay pool. There must be exactly one
6244 delay_class line for each delay pool. For example, to define two
6245 delay pools, one of class 2 and one of class 3, the settings above
6249 delay_pools 4 # 4 delay pools
6250 delay_class 1 2 # pool 1 is a class 2 pool
6251 delay_class 2 3 # pool 2 is a class 3 pool
6252 delay_class 3 4 # pool 3 is a class 4 pool
6253 delay_class 4 5 # pool 4 is a class 5 pool
6255 The delay pool classes are:
6257 class 1 Everything is limited by a single aggregate
6260 class 2 Everything is limited by a single aggregate
6261 bucket as well as an "individual" bucket chosen
6262 from bits 25 through 32 of the IPv4 address.
6264 class 3 Everything is limited by a single aggregate
6265 bucket as well as a "network" bucket chosen
6266 from bits 17 through 24 of the IP address and a
6267 "individual" bucket chosen from bits 17 through
6268 32 of the IPv4 address.
6270 class 4 Everything in a class 3 delay pool, with an
6271 additional limit on a per user basis. This
6272 only takes effect if the username is established
6273 in advance - by forcing authentication in your
6276 class 5 Requests are grouped according their tag (see
6277 external_acl's tag= reply).
6280 Each pool also requires a delay_parameters directive to configure the pool size
6281 and speed limits used whenever the pool is applied to a request. Along with
6282 a set of delay_access directives to determine when it is used.
6284 NOTE: If an IP address is a.b.c.d
6285 -> bits 25 through 32 are "d"
6286 -> bits 17 through 24 are "c"
6287 -> bits 17 through 32 are "c * 256 + d"
6289 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6290 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6292 This clause only supports fast acl types.
6293 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6295 See also delay_parameters and delay_access.
6299 TYPE: delay_pool_access
6301 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6302 IFDEF: USE_DELAY_POOLS
6305 This is used to determine which delay pool a request falls into.
6307 delay_access is sorted per pool and the matching starts with pool 1,
6308 then pool 2, ..., and finally pool N. The first delay pool where the
6309 request is allowed is selected for the request. If it does not allow
6310 the request to any pool then the request is not delayed (default).
6312 For example, if you want some_big_clients in delay
6313 pool 1 and lotsa_little_clients in delay pool 2:
6315 delay_access 1 allow some_big_clients
6316 delay_access 1 deny all
6317 delay_access 2 allow lotsa_little_clients
6318 delay_access 2 deny all
6319 delay_access 3 allow authenticated_clients
6321 See also delay_parameters and delay_class.
6325 NAME: delay_parameters
6326 TYPE: delay_pool_rates
6328 IFDEF: USE_DELAY_POOLS
6331 This defines the parameters for a delay pool. Each delay pool has
6332 a number of "buckets" associated with it, as explained in the
6333 description of delay_class.
6335 For a class 1 delay pool, the syntax is:
6337 delay_parameters pool aggregate
6339 For a class 2 delay pool:
6341 delay_parameters pool aggregate individual
6343 For a class 3 delay pool:
6345 delay_parameters pool aggregate network individual
6347 For a class 4 delay pool:
6349 delay_parameters pool aggregate network individual user
6351 For a class 5 delay pool:
6353 delay_parameters pool tagrate
6355 The option variables are:
6357 pool a pool number - ie, a number between 1 and the
6358 number specified in delay_pools as used in
6361 aggregate the speed limit parameters for the aggregate bucket
6364 individual the speed limit parameters for the individual
6365 buckets (class 2, 3).
6367 network the speed limit parameters for the network buckets
6370 user the speed limit parameters for the user buckets
6373 tagrate the speed limit parameters for the tag buckets
6376 A pair of delay parameters is written restore/maximum, where restore is
6377 the number of bytes (not bits - modem and network speeds are usually
6378 quoted in bits) per second placed into the bucket, and maximum is the
6379 maximum number of bytes which can be in the bucket at any time.
6381 There must be one delay_parameters line for each delay pool.
6384 For example, if delay pool number 1 is a class 2 delay pool as in the
6385 above example, and is being used to strictly limit each host to 64Kbit/sec
6386 (plus overheads), with no overall limit, the line is:
6388 delay_parameters 1 -1/-1 8000/8000
6390 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
6392 Note that the figure -1 is used to represent "unlimited".
6395 And, if delay pool number 2 is a class 3 delay pool as in the above
6396 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6397 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6398 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6399 to permit a decent web page to be downloaded at a decent speed
6400 (if the network is not being limited due to overuse) but slow down
6401 large downloads more significantly:
6403 delay_parameters 2 32000/32000 8000/8000 600/8000
6405 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
6406 8 x 8000 KByte/sec -> 64Kbit/sec.
6407 8 x 600 Byte/sec -> 4800bit/sec.
6410 Finally, for a class 4 delay pool as in the example - each user will
6411 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6413 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6416 See also delay_class and delay_access.
6420 NAME: delay_initial_bucket_level
6421 COMMENT: (percent, 0-100)
6424 IFDEF: USE_DELAY_POOLS
6425 LOC: Config.Delay.initial
6427 The initial bucket percentage is used to determine how much is put
6428 in each bucket when squid starts, is reconfigured, or first notices
6429 a host accessing it (in class 2 and class 3, individual hosts and
6430 networks only have buckets associated with them once they have been
6435 CLIENT DELAY POOL PARAMETERS
6436 -----------------------------------------------------------------------------
6439 NAME: client_delay_pools
6440 TYPE: client_delay_pool_count
6442 IFDEF: USE_DELAY_POOLS
6443 LOC: Config.ClientDelay
6445 This option specifies the number of client delay pools used. It must
6446 preceed other client_delay_* options.
6449 client_delay_pools 2
6451 See also client_delay_parameters and client_delay_access.
6454 NAME: client_delay_initial_bucket_level
6455 COMMENT: (percent, 0-no_limit)
6458 IFDEF: USE_DELAY_POOLS
6459 LOC: Config.ClientDelay.initial
6461 This option determines the initial bucket size as a percentage of
6462 max_bucket_size from client_delay_parameters. Buckets are created
6463 at the time of the "first" connection from the matching IP. Idle
6464 buckets are periodically deleted up.
6466 You can specify more than 100 percent but note that such "oversized"
6467 buckets are not refilled until their size goes down to max_bucket_size
6468 from client_delay_parameters.
6471 client_delay_initial_bucket_level 50
6474 NAME: client_delay_parameters
6475 TYPE: client_delay_pool_rates
6477 IFDEF: USE_DELAY_POOLS
6478 LOC: Config.ClientDelay
6481 This option configures client-side bandwidth limits using the
6484 client_delay_parameters pool speed_limit max_bucket_size
6486 pool is an integer ID used for client_delay_access matching.
6488 speed_limit is bytes added to the bucket per second.
6490 max_bucket_size is the maximum size of a bucket, enforced after any
6491 speed_limit additions.
6493 Please see the delay_parameters option for more information and
6497 client_delay_parameters 1 1024 2048
6498 client_delay_parameters 2 51200 16384
6500 See also client_delay_access.
6504 NAME: client_delay_access
6505 TYPE: client_delay_pool_access
6507 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6508 IFDEF: USE_DELAY_POOLS
6509 LOC: Config.ClientDelay
6511 This option determines the client-side delay pool for the
6514 client_delay_access pool_ID allow|deny acl_name
6516 All client_delay_access options are checked in their pool ID
6517 order, starting with pool 1. The first checked pool with allowed
6518 request is selected for the request. If no ACL matches or there
6519 are no client_delay_access options, the request bandwidth is not
6522 The ACL-selected pool is then used to find the
6523 client_delay_parameters for the request. Client-side pools are
6524 not used to aggregate clients. Clients are always aggregated
6525 based on their source IP addresses (one bucket per source IP).
6527 This clause only supports fast acl types.
6528 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6529 Additionally, only the client TCP connection details are available.
6530 ACLs testing HTTP properties will not work.
6532 Please see delay_access for more examples.
6535 client_delay_access 1 allow low_rate_network
6536 client_delay_access 2 allow vips_network
6539 See also client_delay_parameters and client_delay_pools.
6543 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6544 -----------------------------------------------------------------------------
6549 LOC: Config.Wccp.router
6551 DEFAULT_DOC: WCCP disabled.
6554 Use this option to define your WCCP ``home'' router for
6557 wccp_router supports a single WCCP(v1) router
6559 wccp2_router supports multiple WCCPv2 routers
6561 only one of the two may be used at the same time and defines
6562 which version of WCCP to use.
6566 TYPE: IpAddress_list
6567 LOC: Config.Wccp2.router
6569 DEFAULT_DOC: WCCPv2 disabled.
6572 Use this option to define your WCCP ``home'' router for
6575 wccp_router supports a single WCCP(v1) router
6577 wccp2_router supports multiple WCCPv2 routers
6579 only one of the two may be used at the same time and defines
6580 which version of WCCP to use.
6585 LOC: Config.Wccp.version
6589 This directive is only relevant if you need to set up WCCP(v1)
6590 to some very old and end-of-life Cisco routers. In all other
6591 setups it must be left unset or at the default setting.
6592 It defines an internal version in the WCCP(v1) protocol,
6593 with version 4 being the officially documented protocol.
6595 According to some users, Cisco IOS 11.2 and earlier only
6596 support WCCP version 3. If you're using that or an earlier
6597 version of IOS, you may need to change this value to 3, otherwise
6598 do not specify this parameter.
6601 NAME: wccp2_rebuild_wait
6603 LOC: Config.Wccp2.rebuildwait
6607 If this is enabled Squid will wait for the cache dir rebuild to finish
6608 before sending the first wccp2 HereIAm packet
6611 NAME: wccp2_forwarding_method
6613 LOC: Config.Wccp2.forwarding_method
6617 WCCP2 allows the setting of forwarding methods between the
6618 router/switch and the cache. Valid values are as follows:
6620 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6621 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6623 Currently (as of IOS 12.4) cisco routers only support GRE.
6624 Cisco switches only support the L2 redirect assignment method.
6627 NAME: wccp2_return_method
6629 LOC: Config.Wccp2.return_method
6633 WCCP2 allows the setting of return methods between the
6634 router/switch and the cache for packets that the cache
6635 decides not to handle. Valid values are as follows:
6637 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6638 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6640 Currently (as of IOS 12.4) cisco routers only support GRE.
6641 Cisco switches only support the L2 redirect assignment.
6643 If the "ip wccp redirect exclude in" command has been
6644 enabled on the cache interface, then it is still safe for
6645 the proxy server to use a l2 redirect method even if this
6646 option is set to GRE.
6649 NAME: wccp2_assignment_method
6651 LOC: Config.Wccp2.assignment_method
6655 WCCP2 allows the setting of methods to assign the WCCP hash
6656 Valid values are as follows:
6658 hash - Hash assignment
6659 mask - Mask assignment
6661 As a general rule, cisco routers support the hash assignment method
6662 and cisco switches support the mask assignment method.
6667 LOC: Config.Wccp2.info
6668 DEFAULT_IF_NONE: standard 0
6669 DEFAULT_DOC: Use the 'web-cache' standard service.
6672 WCCP2 allows for multiple traffic services. There are two
6673 types: "standard" and "dynamic". The standard type defines
6674 one service id - http (id 0). The dynamic service ids can be from
6675 51 to 255 inclusive. In order to use a dynamic service id
6676 one must define the type of traffic to be redirected; this is done
6677 using the wccp2_service_info option.
6679 The "standard" type does not require a wccp2_service_info option,
6680 just specifying the service id will suffice.
6682 MD5 service authentication can be enabled by adding
6683 "password=<password>" to the end of this service declaration.
6687 wccp2_service standard 0 # for the 'web-cache' standard service
6688 wccp2_service dynamic 80 # a dynamic service type which will be
6689 # fleshed out with subsequent options.
6690 wccp2_service standard 0 password=foo
6693 NAME: wccp2_service_info
6694 TYPE: wccp2_service_info
6695 LOC: Config.Wccp2.info
6699 Dynamic WCCPv2 services require further information to define the
6700 traffic you wish to have diverted.
6704 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
6705 priority=<priority> ports=<port>,<port>..
6707 The relevant WCCPv2 flags:
6708 + src_ip_hash, dst_ip_hash
6709 + source_port_hash, dst_port_hash
6710 + src_ip_alt_hash, dst_ip_alt_hash
6711 + src_port_alt_hash, dst_port_alt_hash
6714 The port list can be one to eight entries.
6718 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
6719 priority=240 ports=80
6721 Note: the service id must have been defined by a previous
6722 'wccp2_service dynamic <id>' entry.
6727 LOC: Config.Wccp2.weight
6731 Each cache server gets assigned a set of the destination
6732 hash proportional to their weight.
6737 LOC: Config.Wccp.address
6739 DEFAULT_DOC: Address selected by the operating system.
6742 Use this option if you require WCCPv2 to use a specific
6745 The default behavior is to not bind to any specific address.
6750 LOC: Config.Wccp2.address
6752 DEFAULT_DOC: Address selected by the operating system.
6755 Use this option if you require WCCP to use a specific
6758 The default behavior is to not bind to any specific address.
6762 PERSISTENT CONNECTION HANDLING
6763 -----------------------------------------------------------------------------
6765 Also see "pconn_timeout" in the TIMEOUTS section
6768 NAME: client_persistent_connections
6770 LOC: Config.onoff.client_pconns
6773 Persistent connection support for clients.
6774 Squid uses persistent connections (when allowed). You can use
6775 this option to disable persistent connections with clients.
6778 NAME: server_persistent_connections
6780 LOC: Config.onoff.server_pconns
6783 Persistent connection support for servers.
6784 Squid uses persistent connections (when allowed). You can use
6785 this option to disable persistent connections with servers.
6788 NAME: persistent_connection_after_error
6790 LOC: Config.onoff.error_pconns
6793 With this directive the use of persistent connections after
6794 HTTP errors can be disabled. Useful if you have clients
6795 who fail to handle errors on persistent connections proper.
6798 NAME: detect_broken_pconn
6800 LOC: Config.onoff.detect_broken_server_pconns
6803 Some servers have been found to incorrectly signal the use
6804 of HTTP/1.0 persistent connections even on replies not
6805 compatible, causing significant delays. This server problem
6806 has mostly been seen on redirects.
6808 By enabling this directive Squid attempts to detect such
6809 broken replies and automatically assume the reply is finished
6810 after 10 seconds timeout.
6814 CACHE DIGEST OPTIONS
6815 -----------------------------------------------------------------------------
6818 NAME: digest_generation
6819 IFDEF: USE_CACHE_DIGESTS
6821 LOC: Config.onoff.digest_generation
6824 This controls whether the server will generate a Cache Digest
6825 of its contents. By default, Cache Digest generation is
6826 enabled if Squid is compiled with --enable-cache-digests defined.
6829 NAME: digest_bits_per_entry
6830 IFDEF: USE_CACHE_DIGESTS
6832 LOC: Config.digest.bits_per_entry
6835 This is the number of bits of the server's Cache Digest which
6836 will be associated with the Digest entry for a given HTTP
6837 Method and URL (public key) combination. The default is 5.
6840 NAME: digest_rebuild_period
6841 IFDEF: USE_CACHE_DIGESTS
6844 LOC: Config.digest.rebuild_period
6847 This is the wait time between Cache Digest rebuilds.
6850 NAME: digest_rewrite_period
6852 IFDEF: USE_CACHE_DIGESTS
6854 LOC: Config.digest.rewrite_period
6857 This is the wait time between Cache Digest writes to
6861 NAME: digest_swapout_chunk_size
6864 IFDEF: USE_CACHE_DIGESTS
6865 LOC: Config.digest.swapout_chunk_size
6868 This is the number of bytes of the Cache Digest to write to
6869 disk at a time. It defaults to 4096 bytes (4KB), the Squid
6873 NAME: digest_rebuild_chunk_percentage
6874 COMMENT: (percent, 0-100)
6875 IFDEF: USE_CACHE_DIGESTS
6877 LOC: Config.digest.rebuild_chunk_percentage
6880 This is the percentage of the Cache Digest to be scanned at a
6881 time. By default it is set to 10% of the Cache Digest.
6886 -----------------------------------------------------------------------------
6891 LOC: Config.Port.snmp
6893 DEFAULT_DOC: SNMP disabled.
6896 The port number where Squid listens for SNMP requests. To enable
6897 SNMP support set this to a suitable port number. Port number
6898 3401 is often used for the Squid SNMP agent. By default it's
6899 set to "0" (disabled)
6907 LOC: Config.accessList.snmp
6909 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
6912 Allowing or denying access to the SNMP port.
6914 All access to the agent is denied by default.
6917 snmp_access allow|deny [!]aclname ...
6919 This clause only supports fast acl types.
6920 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6923 snmp_access allow snmppublic localhost
6924 snmp_access deny all
6927 NAME: snmp_incoming_address
6929 LOC: Config.Addrs.snmp_incoming
6931 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
6934 Just like 'udp_incoming_address', but for the SNMP port.
6936 snmp_incoming_address is used for the SNMP socket receiving
6937 messages from SNMP agents.
6939 The default snmp_incoming_address is to listen on all
6940 available network interfaces.
6943 NAME: snmp_outgoing_address
6945 LOC: Config.Addrs.snmp_outgoing
6947 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
6950 Just like 'udp_outgoing_address', but for the SNMP port.
6952 snmp_outgoing_address is used for SNMP packets returned to SNMP
6955 If snmp_outgoing_address is not set it will use the same socket
6956 as snmp_incoming_address. Only change this if you want to have
6957 SNMP replies sent using another address than where this Squid
6958 listens for SNMP queries.
6960 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
6961 the same value since they both use the same port.
6966 -----------------------------------------------------------------------------
6969 NAME: icp_port udp_port
6972 DEFAULT_DOC: ICP disabled.
6973 LOC: Config.Port.icp
6975 The port number where Squid sends and receives ICP queries to
6976 and from neighbor caches. The standard UDP port for ICP is 3130.
6979 icp_port @DEFAULT_ICP_PORT@
6986 DEFAULT_DOC: HTCP disabled.
6987 LOC: Config.Port.htcp
6989 The port number where Squid sends and receives HTCP queries to
6990 and from neighbor caches. To turn it on you want to set it to
6997 NAME: log_icp_queries
7001 LOC: Config.onoff.log_udp
7003 If set, ICP queries are logged to access.log. You may wish
7004 do disable this if your ICP load is VERY high to speed things
7005 up or to simplify log analysis.
7008 NAME: udp_incoming_address
7010 LOC:Config.Addrs.udp_incoming
7012 DEFAULT_DOC: Accept packets from all machine interfaces.
7014 udp_incoming_address is used for UDP packets received from other
7017 The default behavior is to not bind to any specific address.
7019 Only change this if you want to have all UDP queries received on
7020 a specific interface/address.
7022 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
7023 modules. Altering it will affect all of them in the same manner.
7025 see also; udp_outgoing_address
7027 NOTE, udp_incoming_address and udp_outgoing_address can not
7028 have the same value since they both use the same port.
7031 NAME: udp_outgoing_address
7033 LOC: Config.Addrs.udp_outgoing
7035 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
7037 udp_outgoing_address is used for UDP packets sent out to other
7040 The default behavior is to not bind to any specific address.
7042 Instead it will use the same socket as udp_incoming_address.
7043 Only change this if you want to have UDP queries sent using another
7044 address than where this Squid listens for UDP queries from other
7047 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7048 modules. Altering it will affect all of them in the same manner.
7050 see also; udp_incoming_address
7052 NOTE, udp_incoming_address and udp_outgoing_address can not
7053 have the same value since they both use the same port.
7060 LOC: Config.onoff.icp_hit_stale
7062 If you want to return ICP_HIT for stale cache objects, set this
7063 option to 'on'. If you have sibling relationships with caches
7064 in other administrative domains, this should be 'off'. If you only
7065 have sibling relationships with caches under your control,
7066 it is probably okay to set this to 'on'.
7067 If set to 'on', your siblings should use the option "allow-miss"
7068 on their cache_peer lines for connecting to you.
7071 NAME: minimum_direct_hops
7074 LOC: Config.minDirectHops
7076 If using the ICMP pinging stuff, do direct fetches for sites
7077 which are no more than this many hops away.
7080 NAME: minimum_direct_rtt
7084 LOC: Config.minDirectRtt
7086 If using the ICMP pinging stuff, do direct fetches for sites
7087 which are no more than this many rtt milliseconds away.
7093 LOC: Config.Netdb.low
7095 The low water mark for the ICMP measurement database.
7097 Note: high watermark controlled by netdb_high directive.
7099 These watermarks are counts, not percents. The defaults are
7100 (low) 900 and (high) 1000. When the high water mark is
7101 reached, database entries will be deleted until the low
7108 LOC: Config.Netdb.high
7110 The high water mark for the ICMP measurement database.
7112 Note: low watermark controlled by netdb_low directive.
7114 These watermarks are counts, not percents. The defaults are
7115 (low) 900 and (high) 1000. When the high water mark is
7116 reached, database entries will be deleted until the low
7120 NAME: netdb_ping_period
7122 LOC: Config.Netdb.period
7125 The minimum period for measuring a site. There will be at
7126 least this much delay between successive pings to the same
7127 network. The default is five minutes.
7134 LOC: Config.onoff.query_icmp
7136 If you want to ask your peers to include ICMP data in their ICP
7137 replies, enable this option.
7139 If your peer has configured Squid (during compilation) with
7140 '--enable-icmp' that peer will send ICMP pings to origin server
7141 sites of the URLs it receives. If you enable this option the
7142 ICP replies from that peer will include the ICMP data (if available).
7143 Then, when choosing a parent cache, Squid will choose the parent with
7144 the minimal RTT to the origin server. When this happens, the
7145 hierarchy field of the access.log will be
7146 "CLOSEST_PARENT_MISS". This option is off by default.
7149 NAME: test_reachability
7153 LOC: Config.onoff.test_reachability
7155 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
7156 instead of ICP_MISS if the target host is NOT in the ICMP
7157 database, or has a zero RTT.
7160 NAME: icp_query_timeout
7163 DEFAULT_DOC: Dynamic detection.
7165 LOC: Config.Timeout.icp_query
7167 Normally Squid will automatically determine an optimal ICP
7168 query timeout value based on the round-trip-time of recent ICP
7169 queries. If you want to override the value determined by
7170 Squid, set this 'icp_query_timeout' to a non-zero value. This
7171 value is specified in MILLISECONDS, so, to use a 2-second
7172 timeout (the old default), you would write:
7174 icp_query_timeout 2000
7177 NAME: maximum_icp_query_timeout
7181 LOC: Config.Timeout.icp_query_max
7183 Normally the ICP query timeout is determined dynamically. But
7184 sometimes it can lead to very large values (say 5 seconds).
7185 Use this option to put an upper limit on the dynamic timeout
7186 value. Do NOT use this option to always use a fixed (instead
7187 of a dynamic) timeout value. To set a fixed timeout see the
7188 'icp_query_timeout' directive.
7191 NAME: minimum_icp_query_timeout
7195 LOC: Config.Timeout.icp_query_min
7197 Normally the ICP query timeout is determined dynamically. But
7198 sometimes it can lead to very small timeouts, even lower than
7199 the normal latency variance on your link due to traffic.
7200 Use this option to put an lower limit on the dynamic timeout
7201 value. Do NOT use this option to always use a fixed (instead
7202 of a dynamic) timeout value. To set a fixed timeout see the
7203 'icp_query_timeout' directive.
7206 NAME: background_ping_rate
7210 LOC: Config.backgroundPingRate
7212 Controls how often the ICP pings are sent to siblings that
7213 have background-ping set.
7217 MULTICAST ICP OPTIONS
7218 -----------------------------------------------------------------------------
7223 LOC: Config.mcast_group_list
7226 This tag specifies a list of multicast groups which your server
7227 should join to receive multicasted ICP queries.
7229 NOTE! Be very careful what you put here! Be sure you
7230 understand the difference between an ICP _query_ and an ICP
7231 _reply_. This option is to be set only if you want to RECEIVE
7232 multicast queries. Do NOT set this option to SEND multicast
7233 ICP (use cache_peer for that). ICP replies are always sent via
7234 unicast, so this option does not affect whether or not you will
7235 receive replies from multicast group members.
7237 You must be very careful to NOT use a multicast address which
7238 is already in use by another group of caches.
7240 If you are unsure about multicast, please read the Multicast
7241 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7243 Usage: mcast_groups 239.128.16.128 224.0.1.20
7245 By default, Squid doesn't listen on any multicast groups.
7248 NAME: mcast_miss_addr
7249 IFDEF: MULTICAST_MISS_STREAM
7251 LOC: Config.mcast_miss.addr
7253 DEFAULT_DOC: disabled.
7255 If you enable this option, every "cache miss" URL will
7256 be sent out on the specified multicast address.
7258 Do not enable this option unless you are are absolutely
7259 certain you understand what you are doing.
7262 NAME: mcast_miss_ttl
7263 IFDEF: MULTICAST_MISS_STREAM
7265 LOC: Config.mcast_miss.ttl
7268 This is the time-to-live value for packets multicasted
7269 when multicasting off cache miss URLs is enabled. By
7270 default this is set to 'site scope', i.e. 16.
7273 NAME: mcast_miss_port
7274 IFDEF: MULTICAST_MISS_STREAM
7276 LOC: Config.mcast_miss.port
7279 This is the port number to be used in conjunction with
7283 NAME: mcast_miss_encode_key
7284 IFDEF: MULTICAST_MISS_STREAM
7286 LOC: Config.mcast_miss.encode_key
7287 DEFAULT: XXXXXXXXXXXXXXXX
7289 The URLs that are sent in the multicast miss stream are
7290 encrypted. This is the encryption key.
7293 NAME: mcast_icp_query_timeout
7297 LOC: Config.Timeout.mcast_icp_query
7299 For multicast peers, Squid regularly sends out ICP "probes" to
7300 count how many other peers are listening on the given multicast
7301 address. This value specifies how long Squid should wait to
7302 count all the replies. The default is 2000 msec, or 2
7307 INTERNAL ICON OPTIONS
7308 -----------------------------------------------------------------------------
7311 NAME: icon_directory
7313 LOC: Config.icons.directory
7314 DEFAULT: @DEFAULT_ICON_DIR@
7316 Where the icons are stored. These are normally kept in
7320 NAME: global_internal_static
7322 LOC: Config.onoff.global_internal_static
7325 This directive controls is Squid should intercept all requests for
7326 /squid-internal-static/ no matter which host the URL is requesting
7327 (default on setting), or if nothing special should be done for
7328 such URLs (off setting). The purpose of this directive is to make
7329 icons etc work better in complex cache hierarchies where it may
7330 not always be possible for all corners in the cache mesh to reach
7331 the server generating a directory listing.
7334 NAME: short_icon_urls
7336 LOC: Config.icons.use_short_names
7339 If this is enabled Squid will use short URLs for icons.
7340 If disabled it will revert to the old behavior of including
7341 it's own name and port in the URL.
7343 If you run a complex cache hierarchy with a mix of Squid and
7344 other proxies you may need to disable this directive.
7349 -----------------------------------------------------------------------------
7352 NAME: error_directory
7354 LOC: Config.errorDirectory
7356 DEFAULT_DOC: Send error pages in the clients preferred language
7358 If you wish to create your own versions of the default
7359 error files to customize them to suit your company copy
7360 the error/template files to another directory and point
7363 WARNING: This option will disable multi-language support
7364 on error pages if used.
7366 The squid developers are interested in making squid available in
7367 a wide variety of languages. If you are making translations for a
7368 language that Squid does not currently provide please consider
7369 contributing your translation back to the project.
7370 http://wiki.squid-cache.org/Translations
7372 The squid developers working on translations are happy to supply drop-in
7373 translated error files in exchange for any new language contributions.
7376 NAME: error_default_language
7377 IFDEF: USE_ERR_LOCALES
7379 LOC: Config.errorDefaultLanguage
7381 DEFAULT_DOC: Generate English language pages.
7383 Set the default language which squid will send error pages in
7384 if no existing translation matches the clients language
7387 If unset (default) generic English will be used.
7389 The squid developers are interested in making squid available in
7390 a wide variety of languages. If you are interested in making
7391 translations for any language see the squid wiki for details.
7392 http://wiki.squid-cache.org/Translations
7395 NAME: error_log_languages
7396 IFDEF: USE_ERR_LOCALES
7398 LOC: Config.errorLogMissingLanguages
7401 Log to cache.log what languages users are attempting to
7402 auto-negotiate for translations.
7404 Successful negotiations are not logged. Only failures
7405 have meaning to indicate that Squid may need an upgrade
7406 of its error page translations.
7409 NAME: err_page_stylesheet
7411 LOC: Config.errorStylesheet
7412 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7414 CSS Stylesheet to pattern the display of Squid default error pages.
7416 For information on CSS see http://www.w3.org/Style/CSS/
7421 LOC: Config.errHtmlText
7424 HTML text to include in error messages. Make this a "mailto"
7425 URL to your admin address, or maybe just a link to your
7426 organizations Web page.
7428 To include this in your error messages, you must rewrite
7429 the error template files (found in the "errors" directory).
7430 Wherever you want the 'err_html_text' line to appear,
7431 insert a %L tag in the error template file.
7434 NAME: email_err_data
7437 LOC: Config.onoff.emailErrData
7440 If enabled, information about the occurred error will be
7441 included in the mailto links of the ERR pages (if %W is set)
7442 so that the email body contains the data.
7443 Syntax is <A HREF="mailto:%w%W">%w</A>
7448 LOC: Config.denyInfoList
7451 Usage: deny_info err_page_name acl
7452 or deny_info http://... acl
7453 or deny_info TCP_RESET acl
7455 This can be used to return a ERR_ page for requests which
7456 do not pass the 'http_access' rules. Squid remembers the last
7457 acl it evaluated in http_access, and if a 'deny_info' line exists
7458 for that ACL Squid returns a corresponding error page.
7460 The acl is typically the last acl on the http_access deny line which
7461 denied access. The exceptions to this rule are:
7462 - When Squid needs to request authentication credentials. It's then
7463 the first authentication related acl encountered
7464 - When none of the http_access lines matches. It's then the last
7465 acl processed on the last http_access line.
7466 - When the decision to deny access was made by an adaptation service,
7467 the acl name is the corresponding eCAP or ICAP service_name.
7469 NP: If providing your own custom error pages with error_directory
7470 you may also specify them by your custom file name:
7471 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7473 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7474 may be specified by prefixing the file name with the code and a colon.
7475 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7477 Alternatively you can tell Squid to reset the TCP connection
7478 by specifying TCP_RESET.
7480 Or you can specify an error URL or URL pattern. The browsers will
7481 get redirected to the specified URL after formatting tags have
7482 been replaced. Redirect will be done with 302 or 307 according to
7483 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7484 the URL. e.g. 303:http://example.com/
7487 %a - username (if available. Password NOT included)
7490 %E - Error description
7492 %H - Request domain name
7493 %i - Client IP Address
7495 %o - Message result from external ACL helper
7496 %p - Request Port number
7497 %P - Request Protocol name
7498 %R - Request URL path
7499 %T - Timestamp in RFC 1123 format
7500 %U - Full canonical URL from client
7501 (HTTPS URLs terminate with *)
7502 %u - Full canonical URL from client
7503 %w - Admin email from squid.conf
7505 %% - Literal percent (%) code
7510 OPTIONS INFLUENCING REQUEST FORWARDING
7511 -----------------------------------------------------------------------------
7514 NAME: nonhierarchical_direct
7516 LOC: Config.onoff.nonhierarchical_direct
7519 By default, Squid will send any non-hierarchical requests
7520 (matching hierarchy_stoplist or not cacheable request type) direct
7523 When this is set to "off", Squid will prefer to send these
7524 requests to parents.
7526 Note that in most configurations, by turning this off you will only
7527 add latency to these request without any improvement in global hit
7530 This option only sets a preference. If the parent is unavailable a
7531 direct connection to the origin server may still be attempted. To
7532 completely prevent direct connections use never_direct.
7537 LOC: Config.onoff.prefer_direct
7540 Normally Squid tries to use parents for most requests. If you for some
7541 reason like it to first try going direct and only use a parent if
7542 going direct fails set this to on.
7544 By combining nonhierarchical_direct off and prefer_direct on you
7545 can set up Squid to use a parent as a backup path if going direct
7548 Note: If you want Squid to use parents for all requests see
7549 the never_direct directive. prefer_direct only modifies how Squid
7550 acts on cacheable requests.
7553 NAME: cache_miss_revalidate
7557 LOC: Config.onoff.cache_miss_revalidate
7559 Whether Squid on cache MISS will pass client revalidation requests
7560 to the server or tries to fetch new content for caching.
7561 This is useful while the cache is mostly empty to more quickly
7562 have the cache populated.
7564 When set to 'on' (default), Squid will pass all client If-* headers
7567 When set to 'off' and if the request is cacheable, Squid will
7568 remove the clients If-Modified-Since and If-None-Match headers from
7569 the request sent to the server.
7574 LOC: Config.accessList.AlwaysDirect
7576 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7578 Usage: always_direct allow|deny [!]aclname ...
7580 Here you can use ACL elements to specify requests which should
7581 ALWAYS be forwarded by Squid to the origin servers without using
7582 any peers. For example, to always directly forward requests for
7583 local servers ignoring any parents or siblings you may have use
7586 acl local-servers dstdomain my.domain.net
7587 always_direct allow local-servers
7589 To always forward FTP requests directly, use
7592 always_direct allow FTP
7594 NOTE: There is a similar, but opposite option named
7595 'never_direct'. You need to be aware that "always_direct deny
7596 foo" is NOT the same thing as "never_direct allow foo". You
7597 may need to use a deny rule to exclude a more-specific case of
7598 some other rule. Example:
7600 acl local-external dstdomain external.foo.net
7601 acl local-servers dstdomain .foo.net
7602 always_direct deny local-external
7603 always_direct allow local-servers
7605 NOTE: If your goal is to make the client forward the request
7606 directly to the origin server bypassing Squid then this needs
7607 to be done in the client configuration. Squid configuration
7608 can only tell Squid how Squid should fetch the object.
7610 NOTE: This directive is not related to caching. The replies
7611 is cached as usual even if you use always_direct. To not cache
7612 the replies see the 'cache' directive.
7614 This clause supports both fast and slow acl types.
7615 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7620 LOC: Config.accessList.NeverDirect
7622 DEFAULT_DOC: Allow DNS results to be used for this request.
7624 Usage: never_direct allow|deny [!]aclname ...
7626 never_direct is the opposite of always_direct. Please read
7627 the description for always_direct if you have not already.
7629 With 'never_direct' you can use ACL elements to specify
7630 requests which should NEVER be forwarded directly to origin
7631 servers. For example, to force the use of a proxy for all
7632 requests, except those in your local domain use something like:
7634 acl local-servers dstdomain .foo.net
7635 never_direct deny local-servers
7636 never_direct allow all
7638 or if Squid is inside a firewall and there are local intranet
7639 servers inside the firewall use something like:
7641 acl local-intranet dstdomain .foo.net
7642 acl local-external dstdomain external.foo.net
7643 always_direct deny local-external
7644 always_direct allow local-intranet
7645 never_direct allow all
7647 This clause supports both fast and slow acl types.
7648 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7652 ADVANCED NETWORKING OPTIONS
7653 -----------------------------------------------------------------------------
7656 NAME: incoming_udp_average incoming_icp_average
7659 LOC: Config.comm_incoming.udp.average
7661 Heavy voodoo here. I can't even believe you are reading this.
7662 Are you crazy? Don't even think about adjusting these unless
7663 you understand the algorithms in comm_select.c first!
7666 NAME: incoming_tcp_average incoming_http_average
7669 LOC: Config.comm_incoming.tcp.average
7671 Heavy voodoo here. I can't even believe you are reading this.
7672 Are you crazy? Don't even think about adjusting these unless
7673 you understand the algorithms in comm_select.c first!
7676 NAME: incoming_dns_average
7679 LOC: Config.comm_incoming.dns.average
7681 Heavy voodoo here. I can't even believe you are reading this.
7682 Are you crazy? Don't even think about adjusting these unless
7683 you understand the algorithms in comm_select.c first!
7686 NAME: min_udp_poll_cnt min_icp_poll_cnt
7689 LOC: Config.comm_incoming.udp.min_poll
7691 Heavy voodoo here. I can't even believe you are reading this.
7692 Are you crazy? Don't even think about adjusting these unless
7693 you understand the algorithms in comm_select.c first!
7696 NAME: min_dns_poll_cnt
7699 LOC: Config.comm_incoming.dns.min_poll
7701 Heavy voodoo here. I can't even believe you are reading this.
7702 Are you crazy? Don't even think about adjusting these unless
7703 you understand the algorithms in comm_select.c first!
7706 NAME: min_tcp_poll_cnt min_http_poll_cnt
7709 LOC: Config.comm_incoming.tcp.min_poll
7711 Heavy voodoo here. I can't even believe you are reading this.
7712 Are you crazy? Don't even think about adjusting these unless
7713 you understand the algorithms in comm_select.c first!
7719 LOC: Config.accept_filter
7723 The name of an accept(2) filter to install on Squid's
7724 listen socket(s). This feature is perhaps specific to
7725 FreeBSD and requires support in the kernel.
7727 The 'httpready' filter delays delivering new connections
7728 to Squid until a full HTTP request has been received.
7729 See the accf_http(9) man page for details.
7731 The 'dataready' filter delays delivering new connections
7732 to Squid until there is some data to process.
7733 See the accf_dataready(9) man page for details.
7737 The 'data' filter delays delivering of new connections
7738 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
7739 You may optionally specify a number of seconds to wait by
7740 'data=N' where N is the number of seconds. Defaults to 30
7741 if not specified. See the tcp(7) man page for details.
7744 accept_filter httpready
7749 NAME: client_ip_max_connections
7751 LOC: Config.client_ip_max_connections
7753 DEFAULT_DOC: No limit.
7755 Set an absolute limit on the number of connections a single
7756 client IP can use. Any more than this and Squid will begin to drop
7757 new connections from the client until it closes some links.
7759 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
7760 connections from the client. For finer control use the ACL access controls.
7762 Requires client_db to be enabled (the default).
7764 WARNING: This may noticably slow down traffic received via external proxies
7765 or NAT devices and cause them to rebound error messages back to their clients.
7768 NAME: tcp_recv_bufsize
7772 DEFAULT_DOC: Use operating system TCP defaults.
7773 LOC: Config.tcpRcvBufsz
7775 Size of receive buffer to set for TCP sockets. Probably just
7776 as easy to change your kernel's default.
7777 Omit from squid.conf to use the default buffer size.
7782 -----------------------------------------------------------------------------
7789 LOC: Adaptation::Icap::TheConfig.onoff
7792 If you want to enable the ICAP module support, set this to on.
7795 NAME: icap_connect_timeout
7798 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
7801 This parameter specifies how long to wait for the TCP connect to
7802 the requested ICAP server to complete before giving up and either
7803 terminating the HTTP transaction or bypassing the failure.
7805 The default for optional services is peer_connect_timeout.
7806 The default for essential services is connect_timeout.
7807 If this option is explicitly set, its value applies to all services.
7810 NAME: icap_io_timeout
7814 DEFAULT_DOC: Use read_timeout.
7815 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
7818 This parameter specifies how long to wait for an I/O activity on
7819 an established, active ICAP connection before giving up and
7820 either terminating the HTTP transaction or bypassing the
7824 NAME: icap_service_failure_limit
7825 COMMENT: limit [in memory-depth time-units]
7826 TYPE: icap_service_failure_limit
7828 LOC: Adaptation::Icap::TheConfig
7831 The limit specifies the number of failures that Squid tolerates
7832 when establishing a new TCP connection with an ICAP service. If
7833 the number of failures exceeds the limit, the ICAP service is
7834 not used for new ICAP requests until it is time to refresh its
7837 A negative value disables the limit. Without the limit, an ICAP
7838 service will not be considered down due to connectivity failures
7839 between ICAP OPTIONS requests.
7841 Squid forgets ICAP service failures older than the specified
7842 value of memory-depth. The memory fading algorithm
7843 is approximate because Squid does not remember individual
7844 errors but groups them instead, splitting the option
7845 value into ten time slots of equal length.
7847 When memory-depth is 0 and by default this option has no
7848 effect on service failure expiration.
7850 Squid always forgets failures when updating service settings
7851 using an ICAP OPTIONS transaction, regardless of this option
7855 # suspend service usage after 10 failures in 5 seconds:
7856 icap_service_failure_limit 10 in 5 seconds
7859 NAME: icap_service_revival_delay
7862 LOC: Adaptation::Icap::TheConfig.service_revival_delay
7865 The delay specifies the number of seconds to wait after an ICAP
7866 OPTIONS request failure before requesting the options again. The
7867 failed ICAP service is considered "down" until fresh OPTIONS are
7870 The actual delay cannot be smaller than the hardcoded minimum
7871 delay of 30 seconds.
7874 NAME: icap_preview_enable
7878 LOC: Adaptation::Icap::TheConfig.preview_enable
7881 The ICAP Preview feature allows the ICAP server to handle the
7882 HTTP message by looking only at the beginning of the message body
7883 or even without receiving the body at all. In some environments,
7884 previews greatly speedup ICAP processing.
7886 During an ICAP OPTIONS transaction, the server may tell Squid what
7887 HTTP messages should be previewed and how big the preview should be.
7888 Squid will not use Preview if the server did not request one.
7890 To disable ICAP Preview for all ICAP services, regardless of
7891 individual ICAP server OPTIONS responses, set this option to "off".
7893 icap_preview_enable off
7896 NAME: icap_preview_size
7899 LOC: Adaptation::Icap::TheConfig.preview_size
7901 DEFAULT_DOC: No preview sent.
7903 The default size of preview data to be sent to the ICAP server.
7904 This value might be overwritten on a per server basis by OPTIONS requests.
7907 NAME: icap_206_enable
7911 LOC: Adaptation::Icap::TheConfig.allow206_enable
7914 206 (Partial Content) responses is an ICAP extension that allows the
7915 ICAP agents to optionally combine adapted and original HTTP message
7916 content. The decision to combine is postponed until the end of the
7917 ICAP response. Squid supports Partial Content extension by default.
7919 Activation of the Partial Content extension is negotiated with each
7920 ICAP service during OPTIONS exchange. Most ICAP servers should handle
7921 negotation correctly even if they do not support the extension, but
7922 some might fail. To disable Partial Content support for all ICAP
7923 services and to avoid any negotiation, set this option to "off".
7929 NAME: icap_default_options_ttl
7932 LOC: Adaptation::Icap::TheConfig.default_options_ttl
7935 The default TTL value for ICAP OPTIONS responses that don't have
7936 an Options-TTL header.
7939 NAME: icap_persistent_connections
7943 LOC: Adaptation::Icap::TheConfig.reuse_connections
7946 Whether or not Squid should use persistent connections to
7950 NAME: adaptation_send_client_ip icap_send_client_ip
7952 IFDEF: USE_ADAPTATION
7954 LOC: Adaptation::Config::send_client_ip
7957 If enabled, Squid shares HTTP client IP information with adaptation
7958 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
7959 For eCAP, Squid sets the libecap::metaClientIp transaction option.
7961 See also: adaptation_uses_indirect_client
7964 NAME: adaptation_send_username icap_send_client_username
7966 IFDEF: USE_ADAPTATION
7968 LOC: Adaptation::Config::send_username
7971 This sends authenticated HTTP client username (if available) to
7972 the adaptation service.
7974 For ICAP, the username value is encoded based on the
7975 icap_client_username_encode option and is sent using the header
7976 specified by the icap_client_username_header option.
7979 NAME: icap_client_username_header
7982 LOC: Adaptation::Icap::TheConfig.client_username_header
7983 DEFAULT: X-Client-Username
7985 ICAP request header name to use for adaptation_send_username.
7988 NAME: icap_client_username_encode
7992 LOC: Adaptation::Icap::TheConfig.client_username_encode
7995 Whether to base64 encode the authenticated client username.
7999 TYPE: icap_service_type
8001 LOC: Adaptation::Icap::TheConfig
8004 Defines a single ICAP service using the following format:
8006 icap_service id vectoring_point uri [option ...]
8009 an opaque identifier or name which is used to direct traffic to
8010 this specific service. Must be unique among all adaptation
8011 services in squid.conf.
8013 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8014 This specifies at which point of transaction processing the
8015 ICAP service should be activated. *_postcache vectoring points
8016 are not yet supported.
8018 uri: icap://servername:port/servicepath
8019 ICAP server and service location.
8021 ICAP does not allow a single service to handle both REQMOD and RESPMOD
8022 transactions. Squid does not enforce that requirement. You can specify
8023 services with the same service_url and different vectoring_points. You
8024 can even specify multiple identical services as long as their
8025 service_names differ.
8027 To activate a service, use the adaptation_access directive. To group
8028 services, use adaptation_service_chain and adaptation_service_set.
8030 Service options are separated by white space. ICAP services support
8031 the following name=value options:
8034 If set to 'on' or '1', the ICAP service is treated as
8035 optional. If the service cannot be reached or malfunctions,
8036 Squid will try to ignore any errors and process the message as
8037 if the service was not enabled. No all ICAP errors can be
8038 bypassed. If set to 0, the ICAP service is treated as
8039 essential and all ICAP errors will result in an error page
8040 returned to the HTTP client.
8042 Bypass is off by default: services are treated as essential.
8045 If set to 'on' or '1', the ICAP service is allowed to
8046 dynamically change the current message adaptation plan by
8047 returning a chain of services to be used next. The services
8048 are specified using the X-Next-Services ICAP response header
8049 value, formatted as a comma-separated list of service names.
8050 Each named service should be configured in squid.conf. Other
8051 services are ignored. An empty X-Next-Services value results
8052 in an empty plan which ends the current adaptation.
8054 Dynamic adaptation plan may cross or cover multiple supported
8055 vectoring points in their natural processing order.
8057 Routing is not allowed by default: the ICAP X-Next-Services
8058 response header is ignored.
8061 Only has effect on split-stack systems. The default on those systems
8062 is to use IPv4-only connections. When set to 'on' this option will
8063 make Squid use IPv6-only connections to contact this ICAP service.
8065 on-overload=block|bypass|wait|force
8066 If the service Max-Connections limit has been reached, do
8067 one of the following for each new ICAP transaction:
8068 * block: send an HTTP error response to the client
8069 * bypass: ignore the "over-connected" ICAP service
8070 * wait: wait (in a FIFO queue) for an ICAP connection slot
8071 * force: proceed, ignoring the Max-Connections limit
8073 In SMP mode with N workers, each worker assumes the service
8074 connection limit is Max-Connections/N, even though not all
8075 workers may use a given service.
8077 The default value is "bypass" if service is bypassable,
8078 otherwise it is set to "wait".
8082 Use the given number as the Max-Connections limit, regardless
8083 of the Max-Connections value given by the service, if any.
8085 Older icap_service format without optional named parameters is
8086 deprecated but supported for backward compatibility.
8089 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
8090 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
8094 TYPE: icap_class_type
8099 This deprecated option was documented to define an ICAP service
8100 chain, even though it actually defined a set of similar, redundant
8101 services, and the chains were not supported.
8103 To define a set of redundant services, please use the
8104 adaptation_service_set directive. For service chains, use
8105 adaptation_service_chain.
8109 TYPE: icap_access_type
8114 This option is deprecated. Please use adaptation_access, which
8115 has the same ICAP functionality, but comes with better
8116 documentation, and eCAP support.
8121 -----------------------------------------------------------------------------
8128 LOC: Adaptation::Ecap::TheConfig.onoff
8131 Controls whether eCAP support is enabled.
8135 TYPE: ecap_service_type
8137 LOC: Adaptation::Ecap::TheConfig
8140 Defines a single eCAP service
8142 ecap_service id vectoring_point uri [option ...]
8145 an opaque identifier or name which is used to direct traffic to
8146 this specific service. Must be unique among all adaptation
8147 services in squid.conf.
8149 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8150 This specifies at which point of transaction processing the
8151 eCAP service should be activated. *_postcache vectoring points
8152 are not yet supported.
8154 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
8155 Squid uses the eCAP service URI to match this configuration
8156 line with one of the dynamically loaded services. Each loaded
8157 eCAP service must have a unique URI. Obtain the right URI from
8158 the service provider.
8160 To activate a service, use the adaptation_access directive. To group
8161 services, use adaptation_service_chain and adaptation_service_set.
8163 Service options are separated by white space. eCAP services support
8164 the following name=value options:
8167 If set to 'on' or '1', the eCAP service is treated as optional.
8168 If the service cannot be reached or malfunctions, Squid will try
8169 to ignore any errors and process the message as if the service
8170 was not enabled. No all eCAP errors can be bypassed.
8171 If set to 'off' or '0', the eCAP service is treated as essential
8172 and all eCAP errors will result in an error page returned to the
8175 Bypass is off by default: services are treated as essential.
8178 If set to 'on' or '1', the eCAP service is allowed to
8179 dynamically change the current message adaptation plan by
8180 returning a chain of services to be used next.
8182 Dynamic adaptation plan may cross or cover multiple supported
8183 vectoring points in their natural processing order.
8185 Routing is not allowed by default.
8187 Older ecap_service format without optional named parameters is
8188 deprecated but supported for backward compatibility.
8192 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
8193 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
8196 NAME: loadable_modules
8198 IFDEF: USE_LOADABLE_MODULES
8199 LOC: Config.loadable_module_names
8202 Instructs Squid to load the specified dynamic module(s) or activate
8203 preloaded module(s).
8205 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
8209 MESSAGE ADAPTATION OPTIONS
8210 -----------------------------------------------------------------------------
8213 NAME: adaptation_service_set
8214 TYPE: adaptation_service_set_type
8215 IFDEF: USE_ADAPTATION
8220 Configures an ordered set of similar, redundant services. This is
8221 useful when hot standby or backup adaptation servers are available.
8223 adaptation_service_set set_name service_name1 service_name2 ...
8225 The named services are used in the set declaration order. The first
8226 applicable adaptation service from the set is used first. The next
8227 applicable service is tried if and only if the transaction with the
8228 previous service fails and the message waiting to be adapted is still
8231 When adaptation starts, broken services are ignored as if they were
8232 not a part of the set. A broken service is a down optional service.
8234 The services in a set must be attached to the same vectoring point
8235 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8237 If all services in a set are optional then adaptation failures are
8238 bypassable. If all services in the set are essential, then a
8239 transaction failure with one service may still be retried using
8240 another service from the set, but when all services fail, the master
8241 transaction fails as well.
8243 A set may contain a mix of optional and essential services, but that
8244 is likely to lead to surprising results because broken services become
8245 ignored (see above), making previously bypassable failures fatal.
8246 Technically, it is the bypassability of the last failed service that
8249 See also: adaptation_access adaptation_service_chain
8252 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
8253 adaptation service_set svcLogger loggerLocal loggerRemote
8256 NAME: adaptation_service_chain
8257 TYPE: adaptation_service_chain_type
8258 IFDEF: USE_ADAPTATION
8263 Configures a list of complementary services that will be applied
8264 one-by-one, forming an adaptation chain or pipeline. This is useful
8265 when Squid must perform different adaptations on the same message.
8267 adaptation_service_chain chain_name service_name1 svc_name2 ...
8269 The named services are used in the chain declaration order. The first
8270 applicable adaptation service from the chain is used first. The next
8271 applicable service is applied to the successful adaptation results of
8272 the previous service in the chain.
8274 When adaptation starts, broken services are ignored as if they were
8275 not a part of the chain. A broken service is a down optional service.
8277 Request satisfaction terminates the adaptation chain because Squid
8278 does not currently allow declaration of RESPMOD services at the
8279 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8281 The services in a chain must be attached to the same vectoring point
8282 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8284 A chain may contain a mix of optional and essential services. If an
8285 essential adaptation fails (or the failure cannot be bypassed for
8286 other reasons), the master transaction fails. Otherwise, the failure
8287 is bypassed as if the failed adaptation service was not in the chain.
8289 See also: adaptation_access adaptation_service_set
8292 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8295 NAME: adaptation_access
8296 TYPE: adaptation_access_type
8297 IFDEF: USE_ADAPTATION
8300 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8302 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8304 adaptation_access service_name allow|deny [!]aclname...
8305 adaptation_access set_name allow|deny [!]aclname...
8307 At each supported vectoring point, the adaptation_access
8308 statements are processed in the order they appear in this
8309 configuration file. Statements pointing to the following services
8310 are ignored (i.e., skipped without checking their ACL):
8312 - services serving different vectoring points
8313 - "broken-but-bypassable" services
8314 - "up" services configured to ignore such transactions
8315 (e.g., based on the ICAP Transfer-Ignore header).
8317 When a set_name is used, all services in the set are checked
8318 using the same rules, to find the first applicable one. See
8319 adaptation_service_set for details.
8321 If an access list is checked and there is a match, the
8322 processing stops: For an "allow" rule, the corresponding
8323 adaptation service is used for the transaction. For a "deny"
8324 rule, no adaptation service is activated.
8326 It is currently not possible to apply more than one adaptation
8327 service at the same vectoring point to the same HTTP transaction.
8329 See also: icap_service and ecap_service
8332 adaptation_access service_1 allow all
8335 NAME: adaptation_service_iteration_limit
8337 IFDEF: USE_ADAPTATION
8338 LOC: Adaptation::Config::service_iteration_limit
8341 Limits the number of iterations allowed when applying adaptation
8342 services to a message. If your longest adaptation set or chain
8343 may have more than 16 services, increase the limit beyond its
8344 default value of 16. If detecting infinite iteration loops sooner
8345 is critical, make the iteration limit match the actual number
8346 of services in your longest adaptation set or chain.
8348 Infinite adaptation loops are most likely with routing services.
8350 See also: icap_service routing=1
8353 NAME: adaptation_masterx_shared_names
8355 IFDEF: USE_ADAPTATION
8356 LOC: Adaptation::Config::masterx_shared_name
8359 For each master transaction (i.e., the HTTP request and response
8360 sequence, including all related ICAP and eCAP exchanges), Squid
8361 maintains a table of metadata. The table entries are (name, value)
8362 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8363 with the master transaction.
8365 This option specifies the table entry names that Squid must accept
8366 from and forward to the adaptation transactions.
8368 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8369 shared table by returning an ICAP header field with a name
8370 specified in adaptation_masterx_shared_names.
8372 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8373 shared table by implementing the libecap::visitEachOption() API
8374 to provide an option with a name specified in
8375 adaptation_masterx_shared_names.
8377 Squid will store and forward the set entry to subsequent adaptation
8378 transactions within the same master transaction scope.
8380 Only one shared entry name is supported at this time.
8383 # share authentication information among ICAP services
8384 adaptation_masterx_shared_names X-Subscriber-ID
8387 NAME: adaptation_meta
8389 IFDEF: USE_ADAPTATION
8390 LOC: Adaptation::Config::metaHeaders
8393 This option allows Squid administrator to add custom ICAP request
8394 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8395 Use it to pass custom authentication tokens and other
8396 transaction-state related meta information to an ICAP/eCAP service.
8398 The addition of a meta header is ACL-driven:
8399 adaptation_meta name value [!]aclname ...
8401 Processing for a given header name stops after the first ACL list match.
8402 Thus, it is impossible to add two headers with the same name. If no ACL
8403 lists match for a given header name, no such header is added. For
8406 # do not debug transactions except for those that need debugging
8407 adaptation_meta X-Debug 1 needs_debugging
8409 # log all transactions except for those that must remain secret
8410 adaptation_meta X-Log 1 !keep_secret
8412 # mark transactions from users in the "G 1" group
8413 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8415 The "value" parameter may be a regular squid.conf token or a "double
8416 quoted string". Within the quoted string, use backslash (\) to escape
8417 any character, which is currently only useful for escaping backslashes
8418 and double quotes. For example,
8419 "this string has one backslash (\\) and two \"quotes\""
8421 Used adaptation_meta header values may be logged via %note
8422 logformat code. If multiple adaptation_meta headers with the same name
8423 are used during master transaction lifetime, the header values are
8424 logged in the order they were used and duplicate values are ignored
8425 (only the first repeated value will be logged).
8431 LOC: Adaptation::Icap::TheConfig.repeat
8432 DEFAULT_IF_NONE: deny all
8434 This ACL determines which retriable ICAP transactions are
8435 retried. Transactions that received a complete ICAP response
8436 and did not have to consume or produce HTTP bodies to receive
8437 that response are usually retriable.
8439 icap_retry allow|deny [!]aclname ...
8441 Squid automatically retries some ICAP I/O timeouts and errors
8442 due to persistent connection race conditions.
8444 See also: icap_retry_limit
8447 NAME: icap_retry_limit
8450 LOC: Adaptation::Icap::TheConfig.repeat_limit
8452 DEFAULT_DOC: No retries are allowed.
8454 Limits the number of retries allowed.
8456 Communication errors due to persistent connection race
8457 conditions are unavoidable, automatically retried, and do not
8458 count against this limit.
8460 See also: icap_retry
8466 -----------------------------------------------------------------------------
8469 NAME: check_hostnames
8472 LOC: Config.onoff.check_hostnames
8474 For security and stability reasons Squid can check
8475 hostnames for Internet standard RFC compliance. If you want
8476 Squid to perform these checks turn this directive on.
8479 NAME: allow_underscore
8482 LOC: Config.onoff.allow_underscore
8484 Underscore characters is not strictly allowed in Internet hostnames
8485 but nevertheless used by many sites. Set this to off if you want
8486 Squid to be strict about the standard.
8487 This check is performed only when check_hostnames is set to on.
8490 NAME: dns_retransmit_interval
8493 LOC: Config.Timeout.idns_retransmit
8495 Initial retransmit interval for DNS queries. The interval is
8496 doubled each time all configured DNS servers have been tried.
8502 LOC: Config.Timeout.idns_query
8504 DNS Query timeout. If no response is received to a DNS query
8505 within this time all DNS servers for the queried domain
8506 are assumed to be unavailable.
8509 NAME: dns_packet_max
8511 DEFAULT_DOC: EDNS disabled
8513 LOC: Config.dns.packet_max
8515 Maximum number of bytes packet size to advertise via EDNS.
8516 Set to "none" to disable EDNS large packet support.
8518 For legacy reasons DNS UDP replies will default to 512 bytes which
8519 is too small for many responses. EDNS provides a means for Squid to
8520 negotiate receiving larger responses back immediately without having
8521 to failover with repeat requests. Responses larger than this limit
8522 will retain the old behaviour of failover to TCP DNS.
8524 Squid has no real fixed limit internally, but allowing packet sizes
8525 over 1500 bytes requires network jumbogram support and is usually not
8528 WARNING: The RFC also indicates that some older resolvers will reply
8529 with failure of the whole request if the extension is added. Some
8530 resolvers have already been identified which will reply with mangled
8531 EDNS response on occasion. Usually in response to many-KB jumbogram
8532 sizes being advertised by Squid.
8533 Squid will currently treat these both as an unable-to-resolve domain
8534 even if it would be resolvable without EDNS.
8541 DEFAULT_DOC: Search for single-label domain names is disabled.
8542 LOC: Config.onoff.res_defnames
8544 Normally the RES_DEFNAMES resolver option is disabled
8545 (see res_init(3)). This prevents caches in a hierarchy
8546 from interpreting single-component hostnames locally. To allow
8547 Squid to handle single-component names, enable this option.
8550 NAME: dns_multicast_local
8554 DEFAULT_DOC: Search for .local and .arpa names is disabled.
8555 LOC: Config.onoff.dns_mdns
8557 When set to on, Squid sends multicast DNS lookups on the local
8558 network for domains ending in .local and .arpa.
8559 This enables local servers and devices to be contacted in an
8560 ad-hoc or zero-configuration network environment.
8563 NAME: dns_nameservers
8566 DEFAULT_DOC: Use operating system definitions
8567 LOC: Config.dns_nameservers
8569 Use this if you want to specify a list of DNS name servers
8570 (IP addresses) to use instead of those given in your
8571 /etc/resolv.conf file.
8573 On Windows platforms, if no value is specified here or in
8574 the /etc/resolv.conf file, the list of DNS name servers are
8575 taken from the Windows registry, both static and dynamic DHCP
8576 configurations are supported.
8578 Example: dns_nameservers 10.0.0.1 192.172.0.4
8583 DEFAULT: @DEFAULT_HOSTS@
8584 LOC: Config.etcHostsPath
8586 Location of the host-local IP name-address associations
8587 database. Most Operating Systems have such a file on different
8589 - Un*X & Linux: /etc/hosts
8590 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
8591 (%SystemRoot% value install default is c:\winnt)
8592 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
8593 (%SystemRoot% value install default is c:\windows)
8594 - Windows 9x/Me: %windir%\hosts
8595 (%windir% value is usually c:\windows)
8596 - Cygwin: /etc/hosts
8598 The file contains newline-separated definitions, in the
8599 form ip_address_in_dotted_form name [name ...] names are
8600 whitespace-separated. Lines beginning with an hash (#)
8601 character are comments.
8603 The file is checked at startup and upon configuration.
8604 If set to 'none', it won't be checked.
8605 If append_domain is used, that domain will be added to
8606 domain-local (i.e. not containing any dot character) host
8612 LOC: Config.appendDomain
8614 DEFAULT_DOC: Use operating system definitions
8616 Appends local domain name to hostnames without any dots in
8617 them. append_domain must begin with a period.
8619 Be warned there are now Internet names with no dots in
8620 them using only top-domain names, so setting this may
8621 cause some Internet sites to become unavailable.
8624 append_domain .yourdomain.com
8627 NAME: ignore_unknown_nameservers
8629 LOC: Config.onoff.ignore_unknown_nameservers
8632 By default Squid checks that DNS responses are received
8633 from the same IP addresses they are sent to. If they
8634 don't match, Squid ignores the response and writes a warning
8635 message to cache.log. You can allow responses from unknown
8636 nameservers by setting this option to 'off'.
8642 LOC: Config.dns.v4_first
8644 With the IPv6 Internet being as fast or faster than IPv4 Internet
8645 for most networks Squid prefers to contact websites over IPv6.
8647 This option reverses the order of preference to make Squid contact
8648 dual-stack websites over IPv4 first. Squid will still perform both
8649 IPv6 and IPv4 DNS lookups before connecting.
8652 This option will restrict the situations under which IPv6
8653 connectivity is used (and tested). Hiding network problems
8654 which would otherwise be detected and warned about.
8658 COMMENT: (number of entries)
8661 LOC: Config.ipcache.size
8663 Maximum number of DNS IP cache entries.
8670 LOC: Config.ipcache.low
8677 LOC: Config.ipcache.high
8679 The size, low-, and high-water marks for the IP cache.
8682 NAME: fqdncache_size
8683 COMMENT: (number of entries)
8686 LOC: Config.fqdncache.size
8688 Maximum number of FQDN cache entries.
8693 -----------------------------------------------------------------------------
8696 NAME: configuration_includes_quoted_values
8698 TYPE: configuration_includes_quoted_values
8700 LOC: ConfigParser::RecognizeQuotedValues
8702 If set, Squid will recognize each "quoted string" after a configuration
8703 directive as a single parameter. The quotes are stripped before the
8704 parameter value is interpreted or used.
8705 See "Values with spaces, quotes, and other special characters"
8706 section for more details.
8713 LOC: Config.onoff.mem_pools
8715 If set, Squid will keep pools of allocated (but unused) memory
8716 available for future use. If memory is a premium on your
8717 system and you believe your malloc library outperforms Squid
8718 routines, disable this.
8721 NAME: memory_pools_limit
8725 LOC: Config.MemPools.limit
8727 Used only with memory_pools on:
8728 memory_pools_limit 50 MB
8730 If set to a non-zero value, Squid will keep at most the specified
8731 limit of allocated (but unused) memory in memory pools. All free()
8732 requests that exceed this limit will be handled by your malloc
8733 library. Squid does not pre-allocate any memory, just safe-keeps
8734 objects that otherwise would be free()d. Thus, it is safe to set
8735 memory_pools_limit to a reasonably high value even if your
8736 configuration will use less memory.
8738 If set to none, Squid will keep all memory it can. That is, there
8739 will be no limit on the total amount of memory used for safe-keeping.
8741 To disable memory allocation optimization, do not set
8742 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
8744 An overhead for maintaining memory pools is not taken into account
8745 when the limit is checked. This overhead is close to four bytes per
8746 object kept. However, pools may actually _save_ memory because of
8747 reduced memory thrashing in your malloc library.
8751 COMMENT: on|off|transparent|truncate|delete
8754 LOC: opt_forwarded_for
8756 If set to "on", Squid will append your client's IP address
8757 in the HTTP requests it forwards. By default it looks like:
8759 X-Forwarded-For: 192.1.2.3
8761 If set to "off", it will appear as
8763 X-Forwarded-For: unknown
8765 If set to "transparent", Squid will not alter the
8766 X-Forwarded-For header in any way.
8768 If set to "delete", Squid will delete the entire
8769 X-Forwarded-For header.
8771 If set to "truncate", Squid will remove all existing
8772 X-Forwarded-For entries, and place the client IP as the sole entry.
8775 NAME: cachemgr_passwd
8776 TYPE: cachemgrpasswd
8778 DEFAULT_DOC: No password. Actions which require password are denied.
8779 LOC: Config.passwd_list
8781 Specify passwords for cachemgr operations.
8783 Usage: cachemgr_passwd password action action ...
8785 Some valid actions are (see cache manager menu for a full list):
8825 * Indicates actions which will not be performed without a
8826 valid password, others can be performed if not listed here.
8828 To disable an action, set the password to "disable".
8829 To allow performing an action without a password, set the
8832 Use the keyword "all" to set the same password for all actions.
8835 cachemgr_passwd secret shutdown
8836 cachemgr_passwd lesssssssecret info stats/objects
8837 cachemgr_passwd disable all
8844 LOC: Config.onoff.client_db
8846 If you want to disable collecting per-client statistics,
8847 turn off client_db here.
8850 NAME: refresh_all_ims
8854 LOC: Config.onoff.refresh_all_ims
8856 When you enable this option, squid will always check
8857 the origin server for an update when a client sends an
8858 If-Modified-Since request. Many browsers use IMS
8859 requests when the user requests a reload, and this
8860 ensures those clients receive the latest version.
8862 By default (off), squid may return a Not Modified response
8863 based on the age of the cached version.
8866 NAME: reload_into_ims
8867 IFDEF: USE_HTTP_VIOLATIONS
8871 LOC: Config.onoff.reload_into_ims
8873 When you enable this option, client no-cache or ``reload''
8874 requests will be changed to If-Modified-Since requests.
8875 Doing this VIOLATES the HTTP standard. Enabling this
8876 feature could make you liable for problems which it
8879 see also refresh_pattern for a more selective approach.
8882 NAME: connect_retries
8884 LOC: Config.connect_retries
8886 DEFAULT_DOC: Do not retry failed connections.
8888 This sets the maximum number of connection attempts made for each
8889 TCP connection. The connect_retries attempts must all still
8890 complete within the connection timeout period.
8892 The default is not to re-try if the first connection attempt fails.
8893 The (not recommended) maximum is 10 tries.
8895 A warning message will be generated if it is set to a too-high
8896 value and the configured value will be over-ridden.
8898 Note: These re-tries are in addition to forward_max_tries
8899 which limit how many different addresses may be tried to find
8903 NAME: retry_on_error
8905 LOC: Config.retry.onerror
8908 If set to ON Squid will automatically retry requests when
8909 receiving an error response with status 403 (Forbidden),
8910 500 (Internal Error), 501 or 503 (Service not available).
8911 Status 502 and 504 (Gateway errors) are always retried.
8913 This is mainly useful if you are in a complex cache hierarchy to
8914 work around access control errors.
8916 NOTE: This retry will attempt to find another working destination.
8917 Which is different from the server which just failed.
8920 NAME: as_whois_server
8922 LOC: Config.as_whois_server
8923 DEFAULT: whois.ra.net
8925 WHOIS server to query for AS numbers. NOTE: AS numbers are
8926 queried only when Squid starts up, not for every request.
8931 LOC: Config.onoff.offline
8934 Enable this option and Squid will never try to validate cached
8938 NAME: uri_whitespace
8939 TYPE: uri_whitespace
8940 LOC: Config.uri_whitespace
8943 What to do with requests that have whitespace characters in the
8946 strip: The whitespace characters are stripped out of the URL.
8947 This is the behavior recommended by RFC2396 and RFC3986
8948 for tolerant handling of generic URI.
8949 NOTE: This is one difference between generic URI and HTTP URLs.
8951 deny: The request is denied. The user receives an "Invalid
8953 This is the behaviour recommended by RFC2616 for safe
8954 handling of HTTP request URL.
8956 allow: The request is allowed and the URI is not changed. The
8957 whitespace characters remain in the URI. Note the
8958 whitespace is passed to redirector processes if they
8960 Note this may be considered a violation of RFC2616
8961 request parsing where whitespace is prohibited in the
8964 encode: The request is allowed and the whitespace characters are
8965 encoded according to RFC1738.
8967 chop: The request is allowed and the URI is chopped at the
8971 NOTE the current Squid implementation of encode and chop violates
8972 RFC2616 by not using a 301 redirect after altering the URL.
8977 LOC: Config.chroot_dir
8980 Specifies a directory where Squid should do a chroot() while
8981 initializing. This also causes Squid to fully drop root
8982 privileges after initializing. This means, for example, if you
8983 use a HTTP port less than 1024 and try to reconfigure, you may
8984 get an error saying that Squid can not open the port.
8987 NAME: balance_on_multiple_ip
8989 LOC: Config.onoff.balance_on_multiple_ip
8992 Modern IP resolvers in squid sort lookup results by preferred access.
8993 By default squid will use these IP in order and only rotates to
8994 the next listed when the most preffered fails.
8996 Some load balancing servers based on round robin DNS have been
8997 found not to preserve user session state across requests
8998 to different IP addresses.
9000 Enabling this directive Squid rotates IP's per request.
9003 NAME: pipeline_prefetch
9004 TYPE: pipelinePrefetch
9005 LOC: Config.pipeline_max_prefetch
9007 DEFAULT_DOC: Do not pre-parse pipelined requests.
9009 HTTP clients may send a pipeline of 1+N requests to Squid using a
9010 single connection, without waiting for Squid to respond to the first
9011 of those requests. This option limits the number of concurrent
9012 requests Squid will try to handle in parallel. If set to N, Squid
9013 will try to receive and process up to 1+N requests on the same
9014 connection concurrently.
9016 Defaults to 0 (off) for bandwidth management and access logging
9019 NOTE: pipelining requires persistent connections to clients.
9021 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
9024 NAME: high_response_time_warning
9027 LOC: Config.warnings.high_rptm
9029 DEFAULT_DOC: disabled.
9031 If the one-minute median response time exceeds this value,
9032 Squid prints a WARNING with debug level 0 to get the
9033 administrators attention. The value is in milliseconds.
9036 NAME: high_page_fault_warning
9038 LOC: Config.warnings.high_pf
9040 DEFAULT_DOC: disabled.
9042 If the one-minute average page fault rate exceeds this
9043 value, Squid prints a WARNING with debug level 0 to get
9044 the administrators attention. The value is in page faults
9048 NAME: high_memory_warning
9050 LOC: Config.warnings.high_memory
9051 IFDEF: HAVE_MSTATS && HAVE_GNUMALLOC_H
9053 DEFAULT_DOC: disabled.
9055 If the memory usage (as determined by gnumalloc, if available and used)
9056 exceeds this amount, Squid prints a WARNING with debug level 0 to get
9057 the administrators attention.
9059 # TODO: link high_memory_warning to mempools?
9061 NAME: sleep_after_fork
9062 COMMENT: (microseconds)
9064 LOC: Config.sleep_after_fork
9067 When this is set to a non-zero value, the main Squid process
9068 sleeps the specified number of microseconds after a fork()
9069 system call. This sleep may help the situation where your
9070 system reports fork() failures due to lack of (virtual)
9071 memory. Note, however, if you have a lot of child
9072 processes, these sleep delays will add up and your
9073 Squid will not service requests for some amount of time
9074 until all the child processes have been started.
9075 On Windows value less then 1000 (1 milliseconds) are
9079 NAME: windows_ipaddrchangemonitor
9080 IFDEF: _SQUID_WINDOWS_
9084 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
9086 On Windows Squid by default will monitor IP address changes and will
9087 reconfigure itself after any detected event. This is very useful for
9088 proxies connected to internet with dial-up interfaces.
9089 In some cases (a Proxy server acting as VPN gateway is one) it could be
9090 desiderable to disable this behaviour setting this to 'off'.
9091 Note: after changing this, Squid service must be restarted.
9096 IFDEF: USE_SQUID_EUI
9098 LOC: Eui::TheConfig.euiLookup
9100 Whether to lookup the EUI or MAC address of a connected client.
9103 NAME: max_filedescriptors max_filedesc
9106 DEFAULT_DOC: Use operating system limits set by ulimit.
9107 LOC: Config.max_filedescriptors
9109 Reduce the maximum number of filedescriptors supported below
9110 the usual operating system defaults.
9112 Remove from squid.conf to inherit the current ulimit setting.
9114 Note: Changing this requires a restart of Squid. Also
9115 not all I/O types supports large values (eg on Windows).
9122 DEFAULT_DOC: SMP support disabled.
9124 Number of main Squid processes or "workers" to fork and maintain.
9125 0: "no daemon" mode, like running "squid -N ..."
9126 1: "no SMP" mode, start one main Squid process daemon (default)
9127 N: start N main Squid process daemons (i.e., SMP mode)
9129 In SMP mode, each worker does nearly all what a single Squid daemon
9130 does (e.g., listen on http_port and forward HTTP requests).
9133 NAME: cpu_affinity_map
9134 TYPE: CpuAffinityMap
9135 LOC: Config.cpuAffinityMap
9137 DEFAULT_DOC: Let operating system decide.
9139 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
9141 Sets 1:1 mapping between Squid processes and CPU cores. For example,
9143 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
9145 affects processes 1 through 4 only and places them on the first
9146 four even cores, starting with core #1.
9148 CPU cores are numbered starting from 1. Requires support for
9149 sched_getaffinity(2) and sched_setaffinity(2) system calls.
9151 Multiple cpu_affinity_map options are merged.
projects / thirdparty / squid.git / blob