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 Conditional configuration
70 If-statements can be used to make configuration directives
74 ... regular configuration directives ...
76 ... regular configuration directives ...]
79 The else part is optional. The keywords "if", "else", and "endif"
80 must be typed on their own lines, as if they were regular
81 configuration directives.
83 NOTE: An else-if condition is not supported.
85 These individual conditions types are supported:
88 Always evaluates to true.
90 Always evaluates to false.
92 Equality comparison of two integer numbers.
97 The following SMP-related preprocessor macros can be used.
99 ${process_name} expands to the current Squid process "name"
100 (e.g., squid1, squid2, or cache1).
102 ${process_number} expands to the current Squid process
103 identifier, which is an integer number (e.g., 1, 2, 3) unique
104 across all Squid processes.
107 # options still not yet ported from 2.7 to 3.x
108 NAME: broken_vary_encoding
111 This option is not yet supported by Squid-3.
117 This option is not yet supported by Squid-3.
120 NAME: collapsed_forwarding
123 This option is not yet supported by Squid-3. see http://bugs.squid-cache.org/show_bug.cgi?id=3495
129 This option is not yet supported by Squid-3.
132 NAME: external_refresh_check
135 This option is not yet supported by Squid-3.
138 NAME: ignore_ims_on_miss
141 This option is not yet supported by Squid-3.
144 NAME: location_rewrite_program location_rewrite_access location_rewrite_children location_rewrite_concurrency
147 This option is not yet supported by Squid-3.
150 NAME: refresh_stale_hit
153 This option is not yet supported by Squid-3.
156 # no Options Removed in 3.3
158 # Options Removed in 3.2
159 NAME: ignore_expect_100
162 Remove this line. The HTTP/1.1 feature is now fully supported by default.
165 NAME: dns_v4_fallback
168 Remove this line. Squid performs a 'Happy Eyeballs' algorithm, the 'fallback' algorithm is no longer relevant.
174 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
177 NAME: maximum_single_addr_tries
180 Replaced by connect_retries. The behaviour has changed, please read the documentation before altering.
186 Remove this line. The feature is supported by default in storage types where update is implemented.
189 NAME: url_rewrite_concurrency
192 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
195 # Options Removed in 3.1
199 Remove this line. DNS is no longer tested on startup.
202 NAME: extension_methods
205 Remove this line. All valid methods for HTTP are accepted by default.
208 # 2.7 Options Removed/Replaced in 3.2
213 # 2.7 Options Removed/Replaced in 3.1
221 Remove this line. HTTP/1.1 is supported by default.
224 NAME: upgrade_http0.9
227 Remove this line. ICY/1.0 streaming protocol is supported by default.
230 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
233 Alter these entries. Use the qos_flows directive instead.
236 # Options Removed in 3.0
240 Since squid-3.0 replace with request_header_access or reply_header_access
241 depending on whether you wish to match client requests or server replies.
244 NAME: httpd_accel_no_pmtu_disc
247 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
250 NAME: wais_relay_host
253 Replace this line with 'cache_peer' configuration.
256 NAME: wais_relay_port
259 Replace this line with 'cache_peer' configuration.
263 OPTIONS FOR AUTHENTICATION
264 -----------------------------------------------------------------------------
273 This is used to define parameters for the various authentication
274 schemes supported by Squid.
276 format: auth_param scheme parameter [setting]
278 The order in which authentication schemes are presented to the client is
279 dependent on the order the scheme first appears in config file. IE
280 has a bug (it's not RFC 2617 compliant) in that it will use the basic
281 scheme if basic is the first entry presented, even if more secure
282 schemes are presented. For now use the order in the recommended
283 settings section below. If other browsers have difficulties (don't
284 recognize the schemes offered even if you are using basic) either
285 put basic first, or disable the other schemes (by commenting out their
288 Once an authentication scheme is fully configured, it can only be
289 shutdown by shutting squid down and restarting. Changes can be made on
290 the fly and activated with a reconfigure. I.E. You can change to a
291 different helper, but not unconfigure the helper completely.
293 Please note that while this directive defines how Squid processes
294 authentication it does not automatically activate authentication.
295 To use authentication you must in addition make use of ACLs based
296 on login name in http_access (proxy_auth, proxy_auth_regex or
297 external with %LOGIN used in the format tag). The browser will be
298 challenged for authentication on the first such acl encountered
299 in http_access processing and will also be re-challenged for new
300 login credentials if the request is being denied by a proxy_auth
303 WARNING: authentication can't be used in a transparently intercepting
304 proxy as the client then thinks it is talking to an origin server and
305 not the proxy. This is a limitation of bending the TCP/IP protocol to
306 transparently intercepting port 80, not a limitation in Squid.
307 Ports flagged 'transparent', 'intercept', or 'tproxy' have
308 authentication disabled.
310 === Parameters for the basic scheme follow. ===
313 Specify the command for the external authenticator. Such a program
314 reads a line containing "username password" and replies with one of
321 the user does not exist.
324 An internal error occurred in the helper, preventing
325 a result being identified.
327 "ERR" and "BH" results may optionally be followed by message="..."
328 containing a description available as %m in the returned error page.
330 If you use an authenticator, make sure you have 1 acl of type
333 By default, the basic authentication scheme is not used unless a
334 program is specified.
336 If you want to use the traditional NCSA proxy authentication, set
337 this line to something like
339 auth_param basic program @DEFAULT_PREFIX@/libexec/basic_ncsa_auth @DEFAULT_PREFIX@/etc/passwd
342 HTTP uses iso-latin-1 as character set, while some authentication
343 backends such as LDAP expects UTF-8. If this is set to on Squid will
344 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
345 username & password to the helper.
347 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
348 The maximum number of authenticator processes to spawn. If you start too few
349 Squid will have to wait for them to process a backlog of credential
350 verifications, slowing it down. When password verifications are
351 done via a (slow) network you are likely to need lots of
352 authenticator processes.
354 The startup= and idle= options permit some skew in the exact amount
355 run. A minimum of startup=N will begin during startup and reconfigure.
356 Squid will start more in groups of up to idle=N in an attempt to meet
357 traffic needs and to keep idle=N free above those traffic needs up to
360 The concurrency= option sets the number of concurrent requests the
361 helper can process. The default of 0 is used for helpers who only
362 supports one request at a time. Setting this to a number greater than
363 0 changes the protocol used to include a channel number first on the
364 request/response line, allowing multiple requests to be sent to the
365 same helper in parallel without waiting for the response.
366 Must not be set unless it's known the helper supports this.
368 auth_param basic children 20 startup=0 idle=1
371 Specifies the realm name which is to be reported to the
372 client for the basic proxy authentication scheme (part of
373 the text the user will see when prompted their username and
374 password). There is no default.
375 auth_param basic realm Squid proxy-caching web server
377 "credentialsttl" timetolive
378 Specifies how long squid assumes an externally validated
379 username:password pair is valid for - in other words how
380 often the helper program is called for that user. Set this
381 low to force revalidation with short lived passwords. Note
382 setting this high does not impact your susceptibility
383 to replay attacks unless you are using an one-time password
384 system (such as SecureID). If you are using such a system,
385 you will be vulnerable to replay attacks unless you also
386 use the max_user_ip ACL in an http_access rule.
388 "casesensitive" on|off
389 Specifies if usernames are case sensitive. Most user databases are
390 case insensitive allowing the same username to be spelled using both
391 lower and upper case letters, but some are case sensitive. This
392 makes a big difference for user_max_ip ACL processing and similar.
393 auth_param basic casesensitive off
395 === Parameters for the digest scheme follow ===
398 Specify the command for the external authenticator. Such
399 a program reads a line containing "username":"realm" and
400 replies with one of three results:
403 the user exists. The ha1= key is mandatory and
404 contains the appropriate H(A1) value, hex encoded.
405 See rfc 2616 for the definition of H(A1).
408 the user does not exist.
411 An internal error occurred in the helper, preventing
412 a result being identified.
414 "ERR" and "BH" results may optionally be followed by message="..."
415 containing a description available as %m in the returned error page.
417 By default, the digest authentication scheme is not used unless a
418 program is specified.
420 If you want to use a digest authenticator, set this line to
423 auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass
426 HTTP uses iso-latin-1 as character set, while some authentication
427 backends such as LDAP expects UTF-8. If this is set to on Squid will
428 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
429 username & password to the helper.
431 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
432 The maximum number of authenticator processes to spawn (default 5).
433 If you start too few Squid will have to wait for them to
434 process a backlog of H(A1) calculations, slowing it down.
435 When the H(A1) calculations are done via a (slow) network
436 you are likely to need lots of authenticator processes.
438 The startup= and idle= options permit some skew in the exact amount
439 run. A minimum of startup=N will begin during startup and reconfigure.
440 Squid will start more in groups of up to idle=N in an attempt to meet
441 traffic needs and to keep idle=N free above those traffic needs up to
444 The concurrency= option sets the number of concurrent requests the
445 helper can process. The default of 0 is used for helpers who only
446 supports one request at a time. Setting this to a number greater than
447 0 changes the protocol used to include a channel number first on the
448 request/response line, allowing multiple requests to be sent to the
449 same helper in parallel without waiting for the response.
450 Must not be set unless it's known the helper supports this.
452 auth_param digest children 20 startup=0 idle=1
455 Specifies the realm name which is to be reported to the
456 client for the digest proxy authentication scheme (part of
457 the text the user will see when prompted their username and
458 password). There is no default.
459 auth_param digest realm Squid proxy-caching web server
461 "nonce_garbage_interval" timeinterval
462 Specifies the interval that nonces that have been issued
463 to client_agent's are checked for validity.
465 "nonce_max_duration" timeinterval
466 Specifies the maximum length of time a given nonce will be
469 "nonce_max_count" number
470 Specifies the maximum number of times a given nonce can be
473 "nonce_strictness" on|off
474 Determines if squid requires strict increment-by-1 behavior
475 for nonce counts, or just incrementing (off - for use when
476 user agents generate nonce counts that occasionally miss 1
477 (ie, 1,2,4,6)). Default off.
479 "check_nonce_count" on|off
480 This directive if set to off can disable the nonce count check
481 completely to work around buggy digest qop implementations in
482 certain mainstream browser versions. Default on to check the
483 nonce count to protect from authentication replay attacks.
485 "post_workaround" on|off
486 This is a workaround to certain buggy browsers who sends
487 an incorrect request digest in POST requests when reusing
488 the same nonce as acquired earlier on a GET request.
490 === NTLM scheme options follow ===
493 Specify the command for the external NTLM authenticator.
494 Such a program reads exchanged NTLMSSP packets with
495 the browser via Squid until authentication is completed.
496 If you use an NTLM authenticator, make sure you have 1 acl
497 of type proxy_auth. By default, the NTLM authenticator program
500 auth_param ntlm program /usr/bin/ntlm_auth
502 "children" numberofchildren [startup=N] [idle=N]
503 The maximum number of authenticator processes to spawn (default 5).
504 If you start too few Squid will have to wait for them to
505 process a backlog of credential verifications, slowing it
506 down. When credential verifications are done via a (slow)
507 network you are likely to need lots of authenticator
510 The startup= and idle= options permit some skew in the exact amount
511 run. A minimum of startup=N will begin during startup and reconfigure.
512 Squid will start more in groups of up to idle=N in an attempt to meet
513 traffic needs and to keep idle=N free above those traffic needs up to
516 auth_param ntlm children 20 startup=0 idle=1
519 If you experience problems with PUT/POST requests when using the
520 Negotiate authentication scheme then you can try setting this to
521 off. This will cause Squid to forcibly close the connection on
522 the initial requests where the browser asks which schemes are
523 supported by the proxy.
525 auth_param ntlm keep_alive on
527 === Options for configuring the NEGOTIATE auth-scheme follow ===
530 Specify the command for the external Negotiate authenticator.
531 This protocol is used in Microsoft Active-Directory enabled setups with
532 the Microsoft Internet Explorer or Mozilla Firefox browsers.
533 Its main purpose is to exchange credentials with the Squid proxy
534 using the Kerberos mechanisms.
535 If you use a Negotiate authenticator, make sure you have at least
536 one acl of type proxy_auth active. By default, the negotiate
537 authenticator program is not used.
538 The only supported program for this role is the ntlm_auth
539 program distributed as part of Samba, version 4 or later.
541 auth_param negotiate program /usr/bin/ntlm_auth --helper-protocol=gss-spnego
543 "children" numberofchildren [startup=N] [idle=N]
544 The maximum number of authenticator processes to spawn (default 5).
545 If you start too few Squid will have to wait for them to
546 process a backlog of credential verifications, slowing it
547 down. When credential verifications are done via a (slow)
548 network you are likely to need lots of authenticator
551 The startup= and idle= options permit some skew in the exact amount
552 run. A minimum of startup=N will begin during startup and reconfigure.
553 Squid will start more in groups of up to idle=N in an attempt to meet
554 traffic needs and to keep idle=N free above those traffic needs up to
557 auth_param negotiate children 20 startup=0 idle=1
560 If you experience problems with PUT/POST requests when using the
561 Negotiate authentication scheme then you can try setting this to
562 off. This will cause Squid to forcibly close the connection on
563 the initial requests where the browser asks which schemes are
564 supported by the proxy.
566 auth_param negotiate keep_alive on
571 #Recommended minimum configuration per scheme:
572 #auth_param negotiate program <uncomment and complete this line to activate>
573 #auth_param negotiate children 20 startup=0 idle=1
574 #auth_param negotiate keep_alive on
576 #auth_param ntlm program <uncomment and complete this line to activate>
577 #auth_param ntlm children 20 startup=0 idle=1
578 #auth_param ntlm keep_alive on
580 #auth_param digest program <uncomment and complete this line>
581 #auth_param digest children 20 startup=0 idle=1
582 #auth_param digest realm Squid proxy-caching web server
583 #auth_param digest nonce_garbage_interval 5 minutes
584 #auth_param digest nonce_max_duration 30 minutes
585 #auth_param digest nonce_max_count 50
587 #auth_param basic program <uncomment and complete this line>
588 #auth_param basic children 5 startup=5 idle=1
589 #auth_param basic realm Squid proxy-caching web server
590 #auth_param basic credentialsttl 2 hours
593 NAME: authenticate_cache_garbage_interval
596 LOC: Config.authenticateGCInterval
598 The time period between garbage collection across the username cache.
599 This is a trade-off between memory utilization (long intervals - say
600 2 days) and CPU (short intervals - say 1 minute). Only change if you
604 NAME: authenticate_ttl
607 LOC: Config.authenticateTTL
609 The time a user & their credentials stay in the logged in
610 user cache since their last request. When the garbage
611 interval passes, all user credentials that have passed their
612 TTL are removed from memory.
615 NAME: authenticate_ip_ttl
617 LOC: Config.authenticateIpTTL
620 If you use proxy authentication and the 'max_user_ip' ACL,
621 this directive controls how long Squid remembers the IP
622 addresses associated with each user. Use a small value
623 (e.g., 60 seconds) if your users might change addresses
624 quickly, as is the case with dialup. You might be safe
625 using a larger value (e.g., 2 hours) in a corporate LAN
626 environment with relatively static address assignments.
631 -----------------------------------------------------------------------------
634 NAME: external_acl_type
635 TYPE: externalAclHelper
636 LOC: Config.externalAclHelperList
639 This option defines external acl classes using a helper program
640 to look up the status
642 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
646 ttl=n TTL in seconds for cached results (defaults to 3600
649 TTL for cached negative lookups (default same
652 Maximum number of acl helper processes spawned to service
653 external acl lookups of this type. (default 20)
655 Minimum number of acl helper processes to spawn during
656 startup and reconfigure to service external acl lookups
657 of this type. (default 0)
659 Number of acl helper processes to keep ahead of traffic
660 loads. Squid will spawn this many at once whenever load
661 rises above the capabilities of existing processes.
662 Up to the value of children-max. (default 1)
663 concurrency=n concurrency level per process. Only used with helpers
664 capable of processing more than one query at a time.
665 cache=n limit the result cache size, default is unbounded.
666 grace=n Percentage remaining of TTL where a refresh of a
667 cached entry should be initiated without needing to
668 wait for a new reply. (default is for no grace period)
669 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
670 ipv4 / ipv6 IP protocol used to communicate with this helper.
671 The default is to auto-detect IPv6 and use it when available.
673 FORMAT specifications
675 %LOGIN Authenticated user login name
676 %EXT_USER Username from previous external acl
677 %EXT_LOG Log details from previous external acl
678 %EXT_TAG Tag from previous external acl
679 %IDENT Ident user name
681 %SRCPORT Client source port
684 %PROTO Requested protocol
686 %PATH Requested URL path
687 %METHOD Request method
688 %MYADDR Squid interface address
689 %MYPORT Squid http_port number
690 %PATH Requested URL-path (including query-string if any)
691 %USER_CERT SSL User certificate in PEM format
692 %USER_CERTCHAIN SSL User certificate chain in PEM format
693 %USER_CERT_xx SSL User certificate subject attribute xx
694 %USER_CA_xx SSL User certificate issuer attribute xx
696 %>{Header} HTTP request header "Header"
698 HTTP request header "Hdr" list member "member"
700 HTTP request header list member using ; as
701 list separator. ; can be any non-alphanumeric
704 %<{Header} HTTP reply header "Header"
706 HTTP reply header "Hdr" list member "member"
708 HTTP reply header list member using ; as
709 list separator. ; can be any non-alphanumeric
712 %% The percent sign. Useful for helpers which need
713 an unchanging input format.
716 General request syntax:
718 [channel-ID] FORMAT-values [acl-values ...]
721 FORMAT-values consists of transaction details expanded with
722 whitespace separation per the config file FORMAT specification
723 using the FORMAT macros listed above.
725 acl-values consists of any string specified in the referencing
726 config 'acl ... external' line. see the "acl external" directive.
728 Request values sent to the helper are URL escaped to protect
729 each value in requests against whitespaces.
731 If using protocol=2.5 then the request sent to the helper is not
732 URL escaped to protect against whitespace.
734 NOTE: protocol=3.0 is deprecated as no longer necessary.
736 When using the concurrency= option the protocol is changed by
737 introducing a query channel tag in front of the request/response.
738 The query channel tag is a number between 0 and concurrency-1.
739 This value must be echoed back unchanged to Squid as the first part
740 of the response relating to its request.
743 The helper receives lines expanded per the above format specification
744 and for each input line returns 1 line starting with OK/ERR/BH result
745 code and optionally followed by additional keywords with more details.
748 General result syntax:
750 [channel-ID] result keyword=value ...
752 Result consists of one of the codes:
755 the ACL test produced a match.
758 the ACL test does not produce a match.
761 An internal error occurred in the helper, preventing
762 a result being identified.
764 The meaning of 'a match' is determined by your squid.conf
765 access control configuration. See the Squid wiki for details.
769 user= The users name (login)
771 password= The users password (for login= cache_peer option)
773 message= Message describing the reason for this response.
774 Available as %o in error pages.
775 Useful on (ERR and BH results).
777 tag= Apply a tag to a request. Only sets a tag once,
778 does not alter existing tags.
780 log= String to be logged in access.log. Available as
781 %ea in logformat specifications.
783 Any keywords may be sent on any response whether OK, ERR or BH.
785 All response keyword values need to be a single token with URL
786 escaping, or enclosed in double quotes (") and escaped using \ on
787 any double quotes or \ characters within the value. The wrapping
788 double quotes are removed before the value is interpreted by Squid.
789 \r and \n are also replace by CR and LF.
791 Some example key values:
795 user="J. \"Bob\" Smith"
802 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
803 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
804 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
805 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
806 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
809 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
810 DEFAULT: localhost src 127.0.0.1/32 ::1
811 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
812 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
814 Defining an Access List
816 Every access list definition must begin with an aclname and acltype,
817 followed by either type-specific arguments or a quoted filename that
820 acl aclname acltype argument ...
821 acl aclname acltype "file" ...
823 When using "file", the file should contain one item per line.
825 Some acl types supports options which changes their default behaviour.
826 The available options are:
828 -i,+i By default, regular expressions are CASE-SENSITIVE. To make them
829 case-insensitive, use the -i option. To return case-sensitive
830 use the +i option between patterns, or make a new ACL line
833 -n Disable lookups and address type conversions. If lookup or
834 conversion is required because the parameter type (IP or
835 domain name) does not match the message address type (domain
836 name or IP), then the ACL would immediately declare a mismatch
837 without any warnings or lookups.
839 -- Used to stop processing all options, in the case the first acl
840 value has '-' character as first character (for example the '-'
841 is a valid domain name)
843 Some acl types require suspending the current request in order
844 to access some external data source.
845 Those which do are marked with the tag [slow], those which
846 don't are marked as [fast].
847 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
848 for further information
850 ***** ACL TYPES AVAILABLE *****
852 acl aclname src ip-address/mask ... # clients IP address [fast]
853 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
854 acl aclname dst [-n] ip-address/mask ... # URL host's IP address [slow]
855 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
857 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
858 # The arp ACL requires the special configure option --enable-arp-acl.
859 # Furthermore, the ARP ACL code is not portable to all operating systems.
860 # It works on Linux, Solaris, Windows, FreeBSD, and some
861 # other *BSD variants.
864 # NOTE: Squid can only determine the MAC address for clients that are on
865 # the same subnet. If the client is on a different subnet,
866 # then Squid cannot find out its MAC address.
868 acl aclname srcdomain .foo.com ...
869 # reverse lookup, from client IP [slow]
870 acl aclname dstdomain [-n] .foo.com ...
871 # Destination server from URL [fast]
872 acl aclname srcdom_regex [-i] \.foo\.com ...
873 # regex matching client name [slow]
874 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
875 # regex matching server [fast]
877 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
878 # based URL is used and no match is found. The name "none" is used
879 # if the reverse lookup fails.
881 acl aclname src_as number ...
882 acl aclname dst_as number ...
884 # Except for access control, AS numbers can be used for
885 # routing of requests to specific caches. Here's an
886 # example for routing all requests for AS#1241 and only
887 # those to mycache.mydomain.net:
888 # acl asexample dst_as 1241
889 # cache_peer_access mycache.mydomain.net allow asexample
890 # cache_peer_access mycache_mydomain.net deny all
892 acl aclname peername myPeer ...
894 # match against a named cache_peer entry
895 # set unique name= on cache_peer lines for reliable use.
897 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
907 # h1:m1 must be less than h2:m2
909 acl aclname url_regex [-i] ^http:// ...
910 # regex matching on whole URL [fast]
911 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
912 # regex matching on URL login field
913 acl aclname urlpath_regex [-i] \.gif$ ...
914 # regex matching on URL path [fast]
916 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
918 acl aclname localport 3128 ... # TCP port the client connected to [fast]
919 # NP: for interception mode this is usually '80'
921 acl aclname myportname 3128 ... # http(s)_port name [fast]
923 acl aclname proto HTTP FTP ... # request protocol [fast]
925 acl aclname method GET POST ... # HTTP request method [fast]
927 acl aclname http_status 200 301 500- 400-403 ...
928 # status code in reply [fast]
930 acl aclname browser [-i] regexp ...
931 # pattern match on User-Agent header (see also req_header below) [fast]
933 acl aclname referer_regex [-i] regexp ...
934 # pattern match on Referer header [fast]
935 # Referer is highly unreliable, so use with care
937 acl aclname ident username ...
938 acl aclname ident_regex [-i] pattern ...
939 # string match on ident output [slow]
940 # use REQUIRED to accept any non-null ident.
942 acl aclname proxy_auth [-i] username ...
943 acl aclname proxy_auth_regex [-i] pattern ...
944 # perform http authentication challenge to the client and match against
945 # supplied credentials [slow]
947 # takes a list of allowed usernames.
948 # use REQUIRED to accept any valid username.
950 # Will use proxy authentication in forward-proxy scenarios, and plain
951 # http authenticaiton in reverse-proxy scenarios
953 # NOTE: when a Proxy-Authentication header is sent but it is not
954 # needed during ACL checking the username is NOT logged
957 # NOTE: proxy_auth requires a EXTERNAL authentication program
958 # to check username/password combinations (see
959 # auth_param directive).
961 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
962 # as the browser needs to be configured for using a proxy in order
963 # to respond to proxy authentication.
965 acl aclname snmp_community string ...
966 # A community string to limit access to your SNMP Agent [fast]
969 # acl snmppublic snmp_community public
971 acl aclname maxconn number
972 # This will be matched when the client's IP address has
973 # more than <number> TCP connections established. [fast]
974 # NOTE: This only measures direct TCP links so X-Forwarded-For
975 # indirect clients are not counted.
977 acl aclname max_user_ip [-s] number
978 # This will be matched when the user attempts to log in from more
979 # than <number> different ip addresses. The authenticate_ip_ttl
980 # parameter controls the timeout on the ip entries. [fast]
981 # If -s is specified the limit is strict, denying browsing
982 # from any further IP addresses until the ttl has expired. Without
983 # -s Squid will just annoy the user by "randomly" denying requests.
984 # (the counter is reset each time the limit is reached and a
986 # NOTE: in acceleration mode or where there is mesh of child proxies,
987 # clients may appear to come from multiple addresses if they are
988 # going through proxy farms, so a limit of 1 may cause user problems.
990 acl aclname random probability
991 # Pseudo-randomly match requests. Based on the probability given.
992 # Probability may be written as a decimal (0.333), fraction (1/3)
993 # or ratio of matches:non-matches (3:5).
995 acl aclname req_mime_type [-i] mime-type ...
996 # regex match against the mime type of the request generated
997 # by the client. Can be used to detect file upload or some
998 # types HTTP tunneling requests [fast]
999 # NOTE: This does NOT match the reply. You cannot use this
1000 # to match the returned file type.
1002 acl aclname req_header header-name [-i] any\.regex\.here
1003 # regex match against any of the known request headers. May be
1004 # thought of as a superset of "browser", "referer" and "mime-type"
1007 acl aclname rep_mime_type [-i] mime-type ...
1008 # regex match against the mime type of the reply received by
1009 # squid. Can be used to detect file download or some
1010 # types HTTP tunneling requests. [fast]
1011 # NOTE: This has no effect in http_access rules. It only has
1012 # effect in rules that affect the reply data stream such as
1013 # http_reply_access.
1015 acl aclname rep_header header-name [-i] any\.regex\.here
1016 # regex match against any of the known reply headers. May be
1017 # thought of as a superset of "browser", "referer" and "mime-type"
1020 acl aclname external class_name [arguments...]
1021 # external ACL lookup via a helper class defined by the
1022 # external_acl_type directive [slow]
1024 acl aclname user_cert attribute values...
1025 # match against attributes in a user SSL certificate
1026 # attribute is one of DN/C/O/CN/L/ST [fast]
1028 acl aclname ca_cert attribute values...
1029 # match against attributes a users issuing CA SSL certificate
1030 # attribute is one of DN/C/O/CN/L/ST [fast]
1032 acl aclname ext_user username ...
1033 acl aclname ext_user_regex [-i] pattern ...
1034 # string match on username returned by external acl helper [slow]
1035 # use REQUIRED to accept any non-null user name.
1037 acl aclname tag tagvalue ...
1038 # string match on tag returned by external acl helper [slow]
1040 acl aclname hier_code codename ...
1041 # string match against squid hierarchy code(s); [fast]
1042 # e.g., DIRECT, PARENT_HIT, NONE, etc.
1044 # NOTE: This has no effect in http_access rules. It only has
1045 # effect in rules that affect the reply data stream such as
1046 # http_reply_access.
1049 acl aclname ssl_error errorname
1050 # match against SSL certificate validation error [fast]
1052 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1055 # The following can be used as shortcuts for certificate properties:
1056 # [ssl::]certHasExpired: the "not after" field is in the past
1057 # [ssl::]certNotYetValid: the "not before" field is in the future
1058 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1059 # [ssl::]certSelfSigned: The certificate is self signed.
1060 # [ssl::]certDomainMismatch: The certificate CN domain does not
1061 # match the name the name of the host we are connecting to.
1063 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1064 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1065 # predefined ACLs, just like the 'all' ACL.
1067 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1068 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1070 acl aclname server_cert_fingerprint [-sha1] fingerprint
1071 # match against server SSL certificate fingerprint [fast]
1073 # The fingerprint is the digest of the DER encoded version
1074 # of the whole certificate. The user should use the form: XX:XX:...
1075 # Optional argument specifies the digest algorithm to use.
1076 # The SHA1 digest algorithm is the default and is currently
1077 # the only algorithm supported (-sha1).
1081 acl macaddress arp 09:00:2b:23:45:67
1082 acl myexample dst_as 1241
1083 acl password proxy_auth REQUIRED
1084 acl fileupload req_mime_type -i ^multipart/form-data$
1085 acl javascript rep_mime_type -i ^application/x-javascript$
1089 # Recommended minimum configuration:
1092 # Example rule allowing access from your local networks.
1093 # Adapt to list your (internal) IP networks from where browsing
1095 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
1096 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
1097 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
1098 acl localnet src fc00::/7 # RFC 4193 local private network range
1099 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1101 acl SSL_ports port 443
1102 acl Safe_ports port 80 # http
1103 acl Safe_ports port 21 # ftp
1104 acl Safe_ports port 443 # https
1105 acl Safe_ports port 70 # gopher
1106 acl Safe_ports port 210 # wais
1107 acl Safe_ports port 1025-65535 # unregistered ports
1108 acl Safe_ports port 280 # http-mgmt
1109 acl Safe_ports port 488 # gss-http
1110 acl Safe_ports port 591 # filemaker
1111 acl Safe_ports port 777 # multiling http
1112 acl CONNECT method CONNECT
1116 NAME: follow_x_forwarded_for
1118 IFDEF: FOLLOW_X_FORWARDED_FOR
1119 LOC: Config.accessList.followXFF
1120 DEFAULT_IF_NONE: deny all
1121 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1123 Allowing or Denying the X-Forwarded-For header to be followed to
1124 find the original source of a request.
1126 Requests may pass through a chain of several other proxies
1127 before reaching us. The X-Forwarded-For header will contain a
1128 comma-separated list of the IP addresses in the chain, with the
1129 rightmost address being the most recent.
1131 If a request reaches us from a source that is allowed by this
1132 configuration item, then we consult the X-Forwarded-For header
1133 to see where that host received the request from. If the
1134 X-Forwarded-For header contains multiple addresses, we continue
1135 backtracking until we reach an address for which we are not allowed
1136 to follow the X-Forwarded-For header, or until we reach the first
1137 address in the list. For the purpose of ACL used in the
1138 follow_x_forwarded_for directive the src ACL type always matches
1139 the address we are testing and srcdomain matches its rDNS.
1141 The end result of this process is an IP address that we will
1142 refer to as the indirect client address. This address may
1143 be treated as the client address for access control, ICAP, delay
1144 pools and logging, depending on the acl_uses_indirect_client,
1145 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1146 log_uses_indirect_client and tproxy_uses_indirect_client options.
1148 This clause only supports fast acl types.
1149 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1151 SECURITY CONSIDERATIONS:
1153 Any host for which we follow the X-Forwarded-For header
1154 can place incorrect information in the header, and Squid
1155 will use the incorrect information as if it were the
1156 source address of the request. This may enable remote
1157 hosts to bypass any access control restrictions that are
1158 based on the client's source addresses.
1162 acl localhost src 127.0.0.1
1163 acl my_other_proxy srcdomain .proxy.example.com
1164 follow_x_forwarded_for allow localhost
1165 follow_x_forwarded_for allow my_other_proxy
1168 NAME: acl_uses_indirect_client
1171 IFDEF: FOLLOW_X_FORWARDED_FOR
1173 LOC: Config.onoff.acl_uses_indirect_client
1175 Controls whether the indirect client address
1176 (see follow_x_forwarded_for) is used instead of the
1177 direct client address in acl matching.
1179 NOTE: maxconn ACL considers direct TCP links and indirect
1180 clients will always have zero. So no match.
1183 NAME: delay_pool_uses_indirect_client
1186 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1188 LOC: Config.onoff.delay_pool_uses_indirect_client
1190 Controls whether the indirect client address
1191 (see follow_x_forwarded_for) is used instead of the
1192 direct client address in delay pools.
1195 NAME: log_uses_indirect_client
1198 IFDEF: FOLLOW_X_FORWARDED_FOR
1200 LOC: Config.onoff.log_uses_indirect_client
1202 Controls whether the indirect client address
1203 (see follow_x_forwarded_for) is used instead of the
1204 direct client address in the access log.
1207 NAME: tproxy_uses_indirect_client
1210 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1212 LOC: Config.onoff.tproxy_uses_indirect_client
1214 Controls whether the indirect client address
1215 (see follow_x_forwarded_for) is used instead of the
1216 direct client address when spoofing the outgoing client.
1218 This has no effect on requests arriving in non-tproxy
1221 SECURITY WARNING: Usage of this option is dangerous
1222 and should not be used trivially. Correct configuration
1223 of follow_x_forewarded_for with a limited set of trusted
1224 sources is required to prevent abuse of your proxy.
1229 LOC: Config.accessList.http
1230 DEFAULT_IF_NONE: deny all
1231 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1233 Allowing or Denying access based on defined access lists
1235 Access to the HTTP port:
1236 http_access allow|deny [!]aclname ...
1238 NOTE on default values:
1240 If there are no "access" lines present, the default is to deny
1243 If none of the "access" lines cause a match, the default is the
1244 opposite of the last line in the list. If the last line was
1245 deny, the default is allow. Conversely, if the last line
1246 is allow, the default will be deny. For these reasons, it is a
1247 good idea to have an "deny all" entry at the end of your access
1248 lists to avoid potential confusion.
1250 This clause supports both fast and slow acl types.
1251 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1256 # Recommended minimum Access Permission configuration:
1258 # Deny requests to certain unsafe ports
1259 http_access deny !Safe_ports
1261 # Deny CONNECT to other than secure SSL ports
1262 http_access deny CONNECT !SSL_ports
1264 # Only allow cachemgr access from localhost
1265 http_access allow localhost manager
1266 http_access deny manager
1268 # We strongly recommend the following be uncommented to protect innocent
1269 # web applications running on the proxy server who think the only
1270 # one who can access services on "localhost" is a local user
1271 #http_access deny to_localhost
1274 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1277 # Example rule allowing access from your local networks.
1278 # Adapt localnet in the ACL section to list your (internal) IP networks
1279 # from where browsing should be allowed
1280 http_access allow localnet
1281 http_access allow localhost
1283 # And finally deny all other access to this proxy
1284 http_access deny all
1288 NAME: adapted_http_access http_access2
1290 LOC: Config.accessList.adapted_http
1292 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1294 Allowing or Denying access based on defined access lists
1296 Essentially identical to http_access, but runs after redirectors
1297 and ICAP/eCAP adaptation. Allowing access control based on their
1300 If not set then only http_access is used.
1303 NAME: http_reply_access
1305 LOC: Config.accessList.reply
1307 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1309 Allow replies to client requests. This is complementary to http_access.
1311 http_reply_access allow|deny [!] aclname ...
1313 NOTE: if there are no access lines present, the default is to allow
1316 If none of the access lines cause a match the opposite of the
1317 last line will apply. Thus it is good practice to end the rules
1318 with an "allow all" or "deny all" entry.
1320 This clause supports both fast and slow acl types.
1321 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1326 LOC: Config.accessList.icp
1328 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1330 Allowing or Denying access to the ICP port based on defined
1333 icp_access allow|deny [!]aclname ...
1335 NOTE: The default if no icp_access lines are present is to
1336 deny all traffic. This default may cause problems with peers
1339 This clause only supports fast acl types.
1340 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1342 # Allow ICP queries from local networks only
1343 #icp_access allow localnet
1344 #icp_access deny all
1350 LOC: Config.accessList.htcp
1352 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1354 Allowing or Denying access to the HTCP port based on defined
1357 htcp_access allow|deny [!]aclname ...
1359 See also htcp_clr_access for details on access control for
1360 cache purge (CLR) HTCP messages.
1362 NOTE: The default if no htcp_access lines are present is to
1363 deny all traffic. This default may cause problems with peers
1364 using the htcp option.
1366 This clause only supports fast acl types.
1367 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1369 # Allow HTCP queries from local networks only
1370 #htcp_access allow localnet
1371 #htcp_access deny all
1374 NAME: htcp_clr_access
1377 LOC: Config.accessList.htcp_clr
1379 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1381 Allowing or Denying access to purge content using HTCP based
1382 on defined access lists.
1383 See htcp_access for details on general HTCP access control.
1385 htcp_clr_access allow|deny [!]aclname ...
1387 This clause only supports fast acl types.
1388 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1390 # Allow HTCP CLR requests from trusted peers
1391 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1392 htcp_clr_access allow htcp_clr_peer
1393 htcp_clr_access deny all
1398 LOC: Config.accessList.miss
1400 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1402 Determins whether network access is permitted when satisfying a request.
1405 to force your neighbors to use you as a sibling instead of
1408 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1409 miss_access deny !localclients
1410 miss_access allow all
1412 This means only your local clients are allowed to fetch relayed/MISS
1413 replies from the network and all other clients can only fetch cached
1416 The default for this setting allows all clients who passed the
1417 http_access rules to relay via this proxy.
1419 This clause only supports fast acl types.
1420 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1423 NAME: ident_lookup_access
1427 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1428 LOC: Ident::TheConfig.identLookup
1430 A list of ACL elements which, if matched, cause an ident
1431 (RFC 931) lookup to be performed for this request. For
1432 example, you might choose to always perform ident lookups
1433 for your main multi-user Unix boxes, but not for your Macs
1434 and PCs. By default, ident lookups are not performed for
1437 To enable ident lookups for specific client addresses, you
1438 can follow this example:
1440 acl ident_aware_hosts src 198.168.1.0/24
1441 ident_lookup_access allow ident_aware_hosts
1442 ident_lookup_access deny all
1444 Only src type ACL checks are fully supported. A srcdomain
1445 ACL might work at times, but it will not always provide
1448 This clause only supports fast acl types.
1449 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1452 NAME: reply_body_max_size
1453 COMMENT: size [acl acl...]
1456 DEFAULT_DOC: No limit is applied.
1457 LOC: Config.ReplyBodySize
1459 This option specifies the maximum size of a reply body. It can be
1460 used to prevent users from downloading very large files, such as
1461 MP3's and movies. When the reply headers are received, the
1462 reply_body_max_size lines are processed, and the first line where
1463 all (if any) listed ACLs are true is used as the maximum body size
1466 This size is checked twice. First when we get the reply headers,
1467 we check the content-length value. If the content length value exists
1468 and is larger than the allowed size, the request is denied and the
1469 user receives an error message that says "the request or reply
1470 is too large." If there is no content-length, and the reply
1471 size exceeds this limit, the client's connection is just closed
1472 and they will receive a partial reply.
1474 WARNING: downstream caches probably can not detect a partial reply
1475 if there is no content-length header, so they will cache
1476 partial responses and give them out as hits. You should NOT
1477 use this option if you have downstream caches.
1479 WARNING: A maximum size smaller than the size of squid's error messages
1480 will cause an infinite loop and crash squid. Ensure that the smallest
1481 non-zero value you use is greater that the maximum header size plus
1482 the size of your largest error page.
1484 If you set this parameter none (the default), there will be
1487 Configuration Format is:
1488 reply_body_max_size SIZE UNITS [acl ...]
1490 reply_body_max_size 10 MB
1496 -----------------------------------------------------------------------------
1499 NAME: http_port ascii_port
1502 LOC: Config.Sockaddr.http
1504 Usage: port [mode] [options]
1505 hostname:port [mode] [options]
1506 1.2.3.4:port [mode] [options]
1508 The socket addresses where Squid will listen for HTTP client
1509 requests. You may specify multiple socket addresses.
1510 There are three forms: port alone, hostname with port, and
1511 IP address with port. If you specify a hostname or IP
1512 address, Squid binds the socket to that specific
1513 address. Most likely, you do not need to bind to a specific
1514 address, so you can use the port number alone.
1516 If you are running Squid in accelerator mode, you
1517 probably want to listen on port 80 also, or instead.
1519 The -a command line option may be used to specify additional
1520 port(s) where Squid listens for proxy request. Such ports will
1521 be plain proxy ports with no options.
1523 You may specify multiple socket addresses on multiple lines.
1527 intercept Support for IP-Layer interception of
1528 outgoing requests without browser settings.
1529 NP: disables authentication and IPv6 on the port.
1531 tproxy Support Linux TPROXY for spoofing outgoing
1532 connections using the client IP address.
1533 NP: disables authentication and maybe IPv6 on the port.
1535 accel Accelerator / reverse proxy mode
1537 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1538 establish secure connection with the client and with
1539 the server, decrypt HTTPS messages as they pass through
1540 Squid, and treat them as unencrypted HTTP messages,
1541 becoming the man-in-the-middle.
1543 The ssl_bump option is required to fully enable
1544 bumping of CONNECT requests.
1546 Omitting the mode flag causes default forward proxy mode to be used.
1549 Accelerator Mode Options:
1551 defaultsite=domainname
1552 What to use for the Host: header if it is not present
1553 in a request. Determines what site (not origin server)
1554 accelerators should consider the default.
1556 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1558 protocol= Protocol to reconstruct accelerated requests with.
1559 Defaults to http for http_port and https for
1562 vport Virtual host port support. Using the http_port number
1563 instead of the port passed on Host: headers.
1565 vport=NN Virtual host port support. Using the specified port
1566 number instead of the port passed on Host: headers.
1569 Act as if this Squid is the origin server.
1570 This currently means generate new Date: and Expires:
1571 headers on HIT instead of adding Age:.
1573 ignore-cc Ignore request Cache-Control headers.
1575 WARNING: This option violates HTTP specifications if
1576 used in non-accelerator setups.
1578 allow-direct Allow direct forwarding in accelerator mode. Normally
1579 accelerated requests are denied direct forwarding as if
1580 never_direct was used.
1582 WARNING: this option opens accelerator mode to security
1583 vulnerabilities usually only affecting in interception
1584 mode. Make sure to protect forwarding with suitable
1585 http_access rules when using this.
1588 SSL Bump Mode Options:
1589 In addition to these options ssl-bump requires TLS/SSL options.
1591 generate-host-certificates[=<on|off>]
1592 Dynamically create SSL server certificates for the
1593 destination hosts of bumped CONNECT requests.When
1594 enabled, the cert and key options are used to sign
1595 generated certificates. Otherwise generated
1596 certificate will be selfsigned.
1597 If there is a CA certificate lifetime of the generated
1598 certificate equals lifetime of the CA certificate. If
1599 generated certificate is selfsigned lifetime is three
1601 This option is enabled by default when ssl-bump is used.
1602 See the ssl-bump option above for more information.
1604 dynamic_cert_mem_cache_size=SIZE
1605 Approximate total RAM size spent on cached generated
1606 certificates. If set to zero, caching is disabled. The
1607 default value is 4MB.
1611 cert= Path to SSL certificate (PEM format).
1613 key= Path to SSL private key file (PEM format)
1614 if not specified, the certificate file is
1615 assumed to be a combined certificate and
1618 version= The version of SSL/TLS supported
1619 1 automatic (default)
1626 cipher= Colon separated list of supported ciphers.
1627 NOTE: some ciphers such as EDH ciphers depend on
1628 additional settings. If those settings are
1629 omitted the ciphers may be silently ignored
1630 by the OpenSSL library.
1632 options= Various SSL implementation options. The most important
1634 NO_SSLv2 Disallow the use of SSLv2
1635 NO_SSLv3 Disallow the use of SSLv3
1636 NO_TLSv1 Disallow the use of TLSv1.0
1637 NO_TLSv1_1 Disallow the use of TLSv1.1
1638 NO_TLSv1_2 Disallow the use of TLSv1.2
1639 SINGLE_DH_USE Always create a new key when using
1640 temporary/ephemeral DH key exchanges
1641 ALL Enable various bug workarounds
1642 suggested as "harmless" by OpenSSL
1643 Be warned that this reduces SSL/TLS
1644 strength to some attacks.
1645 See OpenSSL SSL_CTX_set_options documentation for a
1646 complete list of options.
1648 clientca= File containing the list of CAs to use when
1649 requesting a client certificate.
1651 cafile= File containing additional CA certificates to
1652 use when verifying client certificates. If unset
1653 clientca will be used.
1655 capath= Directory containing additional CA certificates
1656 and CRL lists to use when verifying client certificates.
1658 crlfile= File of additional CRL lists to use when verifying
1659 the client certificate, in addition to CRLs stored in
1660 the capath. Implies VERIFY_CRL flag below.
1662 dhparams= File containing DH parameters for temporary/ephemeral
1663 DH key exchanges. See OpenSSL documentation for details
1664 on how to create this file.
1665 WARNING: EDH ciphers will be silently disabled if this
1668 sslflags= Various flags modifying the use of SSL:
1670 Don't request client certificates
1671 immediately, but wait until acl processing
1672 requires a certificate (not yet implemented).
1674 Don't use the default CA lists built in
1677 Don't allow for session reuse. Each connection
1678 will result in a new SSL session.
1680 Verify CRL lists when accepting client
1683 Verify CRL lists for all certificates in the
1684 client certificate chain.
1686 sslcontext= SSL session ID context identifier.
1690 connection-auth[=on|off]
1691 use connection-auth=off to tell Squid to prevent
1692 forwarding Microsoft connection oriented authentication
1693 (NTLM, Negotiate and Kerberos)
1695 disable-pmtu-discovery=
1696 Control Path-MTU discovery usage:
1697 off lets OS decide on what to do (default).
1698 transparent disable PMTU discovery when transparent
1700 always disable always PMTU discovery.
1702 In many setups of transparently intercepting proxies
1703 Path-MTU discovery can not work on traffic towards the
1704 clients. This is the case when the intercepting device
1705 does not fully track connections and fails to forward
1706 ICMP must fragment messages to the cache server. If you
1707 have such setup and experience that certain clients
1708 sporadically hang or never complete requests set
1709 disable-pmtu-discovery option to 'transparent'.
1711 name= Specifies a internal name for the port. Defaults to
1712 the port specification (port or addr:port)
1714 tcpkeepalive[=idle,interval,timeout]
1715 Enable TCP keepalive probes of idle connections.
1716 In seconds; idle is the initial time before TCP starts
1717 probing the connection, interval how often to probe, and
1718 timeout the time before giving up.
1720 If you run Squid on a dual-homed machine with an internal
1721 and an external interface we recommend you to specify the
1722 internal address:port in http_port. This way Squid will only be
1723 visible on the internal address.
1727 # Squid normally listens to port 3128
1728 http_port @DEFAULT_HTTP_PORT@
1736 LOC: Config.Sockaddr.https
1738 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1740 The socket address where Squid will listen for client requests made
1741 over TLS or SSL connections. Commonly referred to as HTTPS.
1743 This is most useful for situations where you are running squid in
1744 accelerator mode and you want to do the SSL work at the accelerator level.
1746 You may specify multiple socket addresses on multiple lines,
1747 each with their own SSL certificate and/or options.
1751 accel Accelerator / reverse proxy mode
1753 intercept Support for IP-Layer interception of
1754 outgoing requests without browser settings.
1755 NP: disables authentication and IPv6 on the port.
1757 tproxy Support Linux TPROXY for spoofing outgoing
1758 connections using the client IP address.
1759 NP: disables authentication and maybe IPv6 on the port.
1761 ssl-bump For each intercepted connection allowed by ssl_bump
1762 ACLs, establish a secure connection with the client and with
1763 the server, decrypt HTTPS messages as they pass through
1764 Squid, and treat them as unencrypted HTTP messages,
1765 becoming the man-in-the-middle.
1767 An "ssl_bump server-first" match is required to
1768 fully enable bumping of intercepted SSL connections.
1770 Requires tproxy or intercept.
1772 Omitting the mode flag causes default forward proxy mode to be used.
1775 See http_port for a list of generic options
1780 cert= Path to SSL certificate (PEM format).
1782 key= Path to SSL private key file (PEM format)
1783 if not specified, the certificate file is
1784 assumed to be a combined certificate and
1787 version= The version of SSL/TLS supported
1788 1 automatic (default)
1793 cipher= Colon separated list of supported ciphers.
1795 options= Various SSL engine options. The most important
1797 NO_SSLv2 Disallow the use of SSLv2
1798 NO_SSLv3 Disallow the use of SSLv3
1799 NO_TLSv1 Disallow the use of TLSv1
1800 SINGLE_DH_USE Always create a new key when using
1801 temporary/ephemeral DH key exchanges
1802 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1803 documentation for a complete list of options.
1805 clientca= File containing the list of CAs to use when
1806 requesting a client certificate.
1808 cafile= File containing additional CA certificates to
1809 use when verifying client certificates. If unset
1810 clientca will be used.
1812 capath= Directory containing additional CA certificates
1813 and CRL lists to use when verifying client certificates.
1815 crlfile= File of additional CRL lists to use when verifying
1816 the client certificate, in addition to CRLs stored in
1817 the capath. Implies VERIFY_CRL flag below.
1819 dhparams= File containing DH parameters for temporary/ephemeral
1822 sslflags= Various flags modifying the use of SSL:
1824 Don't request client certificates
1825 immediately, but wait until acl processing
1826 requires a certificate (not yet implemented).
1828 Don't use the default CA lists built in
1831 Don't allow for session reuse. Each connection
1832 will result in a new SSL session.
1834 Verify CRL lists when accepting client
1837 Verify CRL lists for all certificates in the
1838 client certificate chain.
1840 sslcontext= SSL session ID context identifier.
1842 generate-host-certificates[=<on|off>]
1843 Dynamically create SSL server certificates for the
1844 destination hosts of bumped SSL requests.When
1845 enabled, the cert and key options are used to sign
1846 generated certificates. Otherwise generated
1847 certificate will be selfsigned.
1848 If there is CA certificate life time of generated
1849 certificate equals lifetime of CA certificate. If
1850 generated certificate is selfsigned lifetime is three
1852 This option is enabled by default when SslBump is used.
1853 See the sslBump option above for more information.
1855 dynamic_cert_mem_cache_size=SIZE
1856 Approximate total RAM size spent on cached generated
1857 certificates. If set to zero, caching is disabled. The
1858 default value is 4MB.
1860 See http_port for a list of available options.
1863 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1866 LOC: Ip::Qos::TheConfig.tosToServer
1868 Allows you to select a TOS/Diffserv value for packets outgoing
1869 on the server side, based on an ACL.
1871 tcp_outgoing_tos ds-field [!]aclname ...
1873 Example where normal_service_net uses the TOS value 0x00
1874 and good_service_net uses 0x20
1876 acl normal_service_net src 10.0.0.0/24
1877 acl good_service_net src 10.0.1.0/24
1878 tcp_outgoing_tos 0x00 normal_service_net
1879 tcp_outgoing_tos 0x20 good_service_net
1881 TOS/DSCP values really only have local significance - so you should
1882 know what you're specifying. For more information, see RFC2474,
1883 RFC2475, and RFC3260.
1885 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1886 "default" to use whatever default your host has. Note that in
1887 practice often only multiples of 4 is usable as the two rightmost bits
1888 have been redefined for use by ECN (RFC 3168 section 23.1).
1890 Processing proceeds in the order specified, and stops at first fully
1894 NAME: clientside_tos
1897 LOC: Ip::Qos::TheConfig.tosToClient
1899 Allows you to select a TOS/Diffserv value for packets being transmitted
1900 on the client-side, based on an ACL.
1902 clientside_tos ds-field [!]aclname ...
1904 Example where normal_service_net uses the TOS value 0x00
1905 and good_service_net uses 0x20
1907 acl normal_service_net src 10.0.0.0/24
1908 acl good_service_net src 10.0.1.0/24
1909 clientside_tos 0x00 normal_service_net
1910 clientside_tos 0x20 good_service_net
1912 Note: This feature is incompatible with qos_flows. Any TOS values set here
1913 will be overwritten by TOS values in qos_flows.
1916 NAME: tcp_outgoing_mark
1918 IFDEF: SO_MARK&&USE_LIBCAP
1920 LOC: Ip::Qos::TheConfig.nfmarkToServer
1922 Allows you to apply a Netfilter mark value to outgoing packets
1923 on the server side, based on an ACL.
1925 tcp_outgoing_mark mark-value [!]aclname ...
1927 Example where normal_service_net uses the mark value 0x00
1928 and good_service_net uses 0x20
1930 acl normal_service_net src 10.0.0.0/24
1931 acl good_service_net src 10.0.1.0/24
1932 tcp_outgoing_mark 0x00 normal_service_net
1933 tcp_outgoing_mark 0x20 good_service_net
1936 NAME: clientside_mark
1938 IFDEF: SO_MARK&&USE_LIBCAP
1940 LOC: Ip::Qos::TheConfig.nfmarkToClient
1942 Allows you to apply a Netfilter mark value to packets being transmitted
1943 on the client-side, based on an ACL.
1945 clientside_mark mark-value [!]aclname ...
1947 Example where normal_service_net uses the mark value 0x00
1948 and good_service_net uses 0x20
1950 acl normal_service_net src 10.0.0.0/24
1951 acl good_service_net src 10.0.1.0/24
1952 clientside_mark 0x00 normal_service_net
1953 clientside_mark 0x20 good_service_net
1955 Note: This feature is incompatible with qos_flows. Any mark values set here
1956 will be overwritten by mark values in qos_flows.
1963 LOC: Ip::Qos::TheConfig
1965 Allows you to select a TOS/DSCP value to mark outgoing
1966 connections with, based on where the reply was sourced. For
1967 platforms using netfilter, allows you to set a netfilter mark
1968 value instead of, or in addition to, a TOS value.
1970 TOS values really only have local significance - so you should
1971 know what you're specifying. For more information, see RFC2474,
1972 RFC2475, and RFC3260.
1974 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1975 in practice often only multiples of 4 is usable as the two rightmost bits
1976 have been redefined for use by ECN (RFC 3168 section 23.1).
1978 Mark values can be any unsigned 32-bit integer value.
1980 This setting is configured by setting the following values:
1982 tos|mark Whether to set TOS or netfilter mark values
1984 local-hit=0xFF Value to mark local cache hits.
1986 sibling-hit=0xFF Value to mark hits from sibling peers.
1988 parent-hit=0xFF Value to mark hits from parent peers.
1990 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
1991 over the preserve-miss feature (see below), unless
1992 mask is specified, in which case only the bits
1993 specified in the mask are written.
1995 The TOS variant of the following features are only possible on Linux
1996 and require your kernel to be patched with the TOS preserving ZPH
1997 patch, available from http://zph.bratcheda.org
1998 No patch is needed to preserve the netfilter mark, which will work
1999 with all variants of netfilter.
2001 disable-preserve-miss
2002 This option disables the preservation of the TOS or netfilter
2003 mark. By default, the existing TOS or netfilter mark value of
2004 the response coming from the remote server will be retained
2005 and masked with miss-mark.
2006 NOTE: in the case of a netfilter mark, the mark must be set on
2007 the connection (using the CONNMARK target) not on the packet
2011 Allows you to mask certain bits in the TOS or mark value
2012 received from the remote server, before copying the value to
2013 the TOS sent towards clients.
2014 Default for tos: 0xFF (TOS from server is not changed).
2015 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2017 All of these features require the --enable-zph-qos compilation flag
2018 (enabled by default). Netfilter marking also requires the
2019 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2020 libcap 2.09+ (--with-libcap).
2024 NAME: tcp_outgoing_address
2027 DEFAULT_DOC: Address selection is performed by the operating system.
2028 LOC: Config.accessList.outgoing_address
2030 Allows you to map requests to different outgoing IP addresses
2031 based on the username or source address of the user making
2034 tcp_outgoing_address ipaddr [[!]aclname] ...
2037 Forwarding clients with dedicated IPs for certain subnets.
2039 acl normal_service_net src 10.0.0.0/24
2040 acl good_service_net src 10.0.2.0/24
2042 tcp_outgoing_address 2001:db8::c001 good_service_net
2043 tcp_outgoing_address 10.1.0.2 good_service_net
2045 tcp_outgoing_address 2001:db8::beef normal_service_net
2046 tcp_outgoing_address 10.1.0.1 normal_service_net
2048 tcp_outgoing_address 2001:db8::1
2049 tcp_outgoing_address 10.1.0.3
2051 Processing proceeds in the order specified, and stops at first fully
2054 Squid will add an implicit IP version test to each line.
2055 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2056 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2059 NOTE: The use of this directive using client dependent ACLs is
2060 incompatible with the use of server side persistent connections. To
2061 ensure correct results it is best to set server_persistent_connections
2062 to off when using this directive in such configurations.
2064 NOTE: The use of this directive to set a local IP on outgoing TCP links
2065 is incompatible with using TPROXY to set client IP out outbound TCP links.
2066 When needing to contact peers use the no-tproxy cache_peer option and the
2067 client_dst_passthru directive re-enable normal forwarding such as this.
2071 NAME: host_verify_strict
2074 LOC: Config.onoff.hostStrictVerify
2076 Regardless of this option setting, when dealing with intercepted
2077 traffic, Squid always verifies that the destination IP address matches
2078 the Host header domain or IP (called 'authority form URL').
2080 This enforcement is performed to satisfy a MUST-level requirement in
2081 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2082 authority of the origin server or gateway given by the original URL".
2085 Squid always responds with an HTTP 409 (Conflict) error
2086 page and logs a security warning if there is no match.
2088 Squid verifies that the destination IP address matches
2089 the Host header for forward-proxy and reverse-proxy traffic
2090 as well. For those traffic types, Squid also enables the
2091 following checks, comparing the corresponding Host header
2092 and Request-URI components:
2094 * The host names (domain or IP) must be identical,
2095 but valueless or missing Host header disables all checks.
2096 For the two host names to match, both must be either IP
2099 * Port numbers must be identical, but if a port is missing
2100 the scheme-default port is assumed.
2103 When set to OFF (the default):
2104 Squid allows suspicious requests to continue but logs a
2105 security warning and blocks caching of the response.
2107 * Forward-proxy traffic is not checked at all.
2109 * Reverse-proxy traffic is not checked at all.
2111 * Intercepted traffic which passes verification is handled
2112 according to client_dst_passthru.
2114 * Intercepted requests which fail verification are sent
2115 to the client original destination instead of DIRECT.
2116 This overrides 'client_dst_passthru off'.
2118 For now suspicious intercepted CONNECT requests are always
2119 responded to with an HTTP 409 (Conflict) error page.
2124 As described in CVE-2009-0801 when the Host: header alone is used
2125 to determine the destination of a request it becomes trivial for
2126 malicious scripts on remote websites to bypass browser same-origin
2127 security policy and sandboxing protections.
2129 The cause of this is that such applets are allowed to perform their
2130 own HTTP stack, in which case the same-origin policy of the browser
2131 sandbox only verifies that the applet tries to contact the same IP
2132 as from where it was loaded at the IP level. The Host: header may
2133 be different from the connected IP and approved origin.
2137 NAME: client_dst_passthru
2140 LOC: Config.onoff.client_dst_passthru
2142 With NAT or TPROXY intercepted traffic Squid may pass the request
2143 directly to the original client destination IP or seek a faster
2144 source using the HTTP Host header.
2146 Using Host to locate alternative servers can provide faster
2147 connectivity with a range of failure recovery options.
2148 But can also lead to connectivity trouble when the client and
2149 server are attempting stateful interactions unaware of the proxy.
2151 This option (on by default) prevents alternative DNS entries being
2152 located to send intercepted traffic DIRECT to an origin server.
2153 The clients original destination IP and port will be used instead.
2155 Regardless of this option setting, when dealing with intercepted
2156 traffic Squid will verify the Host: header and any traffic which
2157 fails Host verification will be treated as if this option were ON.
2159 see host_verify_strict for details on the verification process.
2164 -----------------------------------------------------------------------------
2167 NAME: ssl_unclean_shutdown
2171 LOC: Config.SSL.unclean_shutdown
2173 Some browsers (especially MSIE) bugs out on SSL shutdown
2180 LOC: Config.SSL.ssl_engine
2183 The OpenSSL engine to use. You will need to set this if you
2184 would like to use hardware SSL acceleration for example.
2187 NAME: sslproxy_client_certificate
2190 LOC: Config.ssl_client.cert
2193 Client SSL Certificate to use when proxying https:// URLs
2196 NAME: sslproxy_client_key
2199 LOC: Config.ssl_client.key
2202 Client SSL Key to use when proxying https:// URLs
2205 NAME: sslproxy_version
2208 DEFAULT_DOC: automatic SSL/TLS version negotiation
2209 LOC: Config.ssl_client.version
2212 SSL version level to use when proxying https:// URLs
2214 The versions of SSL/TLS supported:
2216 1 automatic (default)
2224 NAME: sslproxy_options
2227 LOC: Config.ssl_client.options
2230 SSL implementation options to use when proxying https:// URLs
2232 The most important being:
2234 NO_SSLv2 Disallow the use of SSLv2
2235 NO_SSLv3 Disallow the use of SSLv3
2236 NO_TLSv1 Disallow the use of TLSv1.0
2237 NO_TLSv1_1 Disallow the use of TLSv1.1
2238 NO_TLSv1_2 Disallow the use of TLSv1.2
2240 Always create a new key when using temporary/ephemeral
2243 Disable use of RFC5077 session tickets. Some servers
2244 may have problems understanding the TLS extension due
2245 to ambiguous specification in RFC4507.
2246 ALL Enable various bug workarounds suggested as "harmless"
2247 by OpenSSL. Be warned that this may reduce SSL/TLS
2248 strength to some attacks.
2250 See the OpenSSL SSL_CTX_set_options documentation for a
2251 complete list of possible options.
2254 NAME: sslproxy_cipher
2257 LOC: Config.ssl_client.cipher
2260 SSL cipher list to use when proxying https:// URLs
2262 Colon separated list of supported ciphers.
2265 NAME: sslproxy_cafile
2268 LOC: Config.ssl_client.cafile
2271 file containing CA certificates to use when verifying server
2272 certificates while proxying https:// URLs
2275 NAME: sslproxy_capath
2278 LOC: Config.ssl_client.capath
2281 directory containing CA certificates to use when verifying
2282 server certificates while proxying https:// URLs
2287 TYPE: sslproxy_ssl_bump
2288 LOC: Config.accessList.ssl_bump
2289 DEFAULT_DOC: Does not bump unless rules are present in squid.conf
2292 This option is consulted when a CONNECT request is received on
2293 an http_port (or a new connection is intercepted at an
2294 https_port), provided that port was configured with an ssl-bump
2295 flag. The subsequent data on the connection is either treated as
2296 HTTPS and decrypted OR tunneled at TCP level without decryption,
2297 depending on the first bumping "mode" which ACLs match.
2299 ssl_bump <mode> [!]acl ...
2301 The following bumping modes are supported:
2304 Allow bumping of the connection. Establish a secure connection
2305 with the client first, then connect to the server. This old mode
2306 does not allow Squid to mimic server SSL certificate and does
2307 not work with intercepted SSL connections.
2310 Allow bumping of the connection. Establish a secure connection
2311 with the server first, then establish a secure connection with
2312 the client, using a mimicked server certificate. Works with both
2313 CONNECT requests and intercepted SSL connections.
2316 Become a TCP tunnel without decoding the connection.
2317 Works with both CONNECT requests and intercepted SSL
2318 connections. This is the default behavior when no
2319 ssl_bump option is given or no ssl_bump ACLs match.
2321 By default, no connections are bumped.
2323 The first matching ssl_bump option wins. If no ACLs match, the
2324 connection is not bumped. Unlike most allow/deny ACL lists, ssl_bump
2325 does not have an implicit "negate the last given option" rule. You
2326 must make that rule explicit if you convert old ssl_bump allow/deny
2327 rules that rely on such an implicit rule.
2329 This clause supports both fast and slow acl types.
2330 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2332 See also: http_port ssl-bump, https_port ssl-bump
2335 # Example: Bump all requests except those originating from
2336 # localhost or those going to example.com.
2338 acl broken_sites dstdomain .example.com
2339 ssl_bump none localhost
2340 ssl_bump none broken_sites
2341 ssl_bump server-first all
2344 NAME: sslproxy_flags
2347 LOC: Config.ssl_client.flags
2350 Various flags modifying the use of SSL while proxying https:// URLs:
2351 DONT_VERIFY_PEER Accept certificates that fail verification.
2352 For refined control, see sslproxy_cert_error.
2353 NO_DEFAULT_CA Don't use the default CA list built in
2357 NAME: sslproxy_cert_error
2360 DEFAULT_DOC: Server certificate errors terminate the transaction.
2361 LOC: Config.ssl_client.cert_error
2364 Use this ACL to bypass server certificate validation errors.
2366 For example, the following lines will bypass all validation errors
2367 when talking to servers for example.com. All other
2368 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2370 acl BrokenButTrustedServers dstdomain example.com
2371 sslproxy_cert_error allow BrokenButTrustedServers
2372 sslproxy_cert_error deny all
2374 This clause only supports fast acl types.
2375 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2376 Using slow acl types may result in server crashes
2378 Without this option, all server certificate validation errors
2379 terminate the transaction to protect Squid and the client.
2382 Bypassing validation errors is dangerous because an
2383 error usually implies that the server cannot be trusted
2384 and the connection may be insecure.
2386 See also: sslproxy_flags and DONT_VERIFY_PEER.
2389 NAME: sslproxy_cert_sign
2392 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2393 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2394 POSTSCRIPTUM: signTrusted all
2395 TYPE: sslproxy_cert_sign
2396 LOC: Config.ssl_client.cert_sign
2399 sslproxy_cert_sign <signing algorithm> acl ...
2401 The following certificate signing algorithms are supported:
2404 Sign using the configured CA certificate which is usually
2405 placed in and trusted by end-user browsers. This is the
2406 default for trusted origin server certificates.
2409 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2410 This is the default for untrusted origin server certificates
2411 that are not self-signed (see ssl::certUntrusted).
2414 Sign using a self-signed certificate with the right CN to
2415 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2416 browser. This is the default for self-signed origin server
2417 certificates (see ssl::certSelfSigned).
2419 This clause only supports fast acl types.
2421 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2422 signing algorithm to generate the certificate and ignores all
2423 subsequent sslproxy_cert_sign options (the first match wins). If no
2424 acl(s) match, the default signing algorithm is determined by errors
2425 detected when obtaining and validating the origin server certificate.
2427 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2428 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2429 CONNECT request that carries a domain name. In all other cases (CONNECT
2430 to an IP address or an intercepted SSL connection), Squid cannot detect
2431 the domain mismatch at certificate generation time when
2432 bump-server-first is used.
2435 NAME: sslproxy_cert_adapt
2438 TYPE: sslproxy_cert_adapt
2439 LOC: Config.ssl_client.cert_adapt
2442 sslproxy_cert_adapt <adaptation algorithm> acl ...
2444 The following certificate adaptation algorithms are supported:
2447 Sets the "Not After" property to the "Not After" property of
2448 the CA certificate used to sign generated certificates.
2451 Sets the "Not Before" property to the "Not Before" property of
2452 the CA certificate used to sign generated certificates.
2454 setCommonName or setCommonName{CN}
2455 Sets Subject.CN property to the host name specified as a
2456 CN parameter or, if no explicit CN parameter was specified,
2457 extracted from the CONNECT request. It is a misconfiguration
2458 to use setCommonName without an explicit parameter for
2459 intercepted or tproxied SSL connections.
2461 This clause only supports fast acl types.
2463 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2464 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2465 corresponding adaptation algorithm to generate the certificate and
2466 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2467 group (i.e., the first match wins within each algorithm group). If no
2468 acl(s) match, the default mimicking action takes place.
2470 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2471 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2472 CONNECT request that carries a domain name. In all other cases (CONNECT
2473 to an IP address or an intercepted SSL connection), Squid cannot detect
2474 the domain mismatch at certificate generation time when
2475 bump-server-first is used.
2478 NAME: sslpassword_program
2481 LOC: Config.Program.ssl_password
2484 Specify a program used for entering SSL key passphrases
2485 when using encrypted SSL certificate keys. If not specified
2486 keys must either be unencrypted, or Squid started with the -N
2487 option to allow it to query interactively for the passphrase.
2489 The key file name is given as argument to the program allowing
2490 selection of the right password if you have multiple encrypted
2495 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2496 -----------------------------------------------------------------------------
2499 NAME: sslcrtd_program
2502 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2503 LOC: Ssl::TheConfig.ssl_crtd
2505 Specify the location and options of the executable for ssl_crtd process.
2506 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2507 For more information use:
2508 @DEFAULT_SSL_CRTD@ -h
2511 NAME: sslcrtd_children
2512 TYPE: HelperChildConfig
2514 DEFAULT: 32 startup=5 idle=1
2515 LOC: Ssl::TheConfig.ssl_crtdChildren
2517 The maximum number of processes spawn to service ssl server.
2518 The maximum this may be safely set to is 32.
2520 The startup= and idle= options allow some measure of skew in your
2525 Sets the minimum number of processes to spawn when Squid
2526 starts or reconfigures. When set to zero the first request will
2527 cause spawning of the first child process to handle it.
2529 Starting too few children temporary slows Squid under load while it
2530 tries to spawn enough additional processes to cope with traffic.
2534 Sets a minimum of how many processes Squid is to try and keep available
2535 at all times. When traffic begins to rise above what the existing
2536 processes can handle this many more will be spawned up to the maximum
2537 configured. A minimum setting of 1 is required.
2539 You must have at least one ssl_crtd process.
2542 NAME: sslcrtvalidator_program
2546 LOC: Ssl::TheConfig.ssl_crt_validator
2548 Specify the location and options of the executable for ssl_crt_validator
2551 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
2554 ttl=n TTL in seconds for cached results. The default is 60 secs
2555 cache=n limit the result cache size. The default value is 2048
2558 NAME: sslcrtvalidator_children
2559 TYPE: HelperChildConfig
2561 DEFAULT: 32 startup=5 idle=1 concurrency=1
2562 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2564 The maximum number of processes spawn to service SSL server.
2565 The maximum this may be safely set to is 32.
2567 The startup= and idle= options allow some measure of skew in your
2572 Sets the minimum number of processes to spawn when Squid
2573 starts or reconfigures. When set to zero the first request will
2574 cause spawning of the first child process to handle it.
2576 Starting too few children temporary slows Squid under load while it
2577 tries to spawn enough additional processes to cope with traffic.
2581 Sets a minimum of how many processes Squid is to try and keep available
2582 at all times. When traffic begins to rise above what the existing
2583 processes can handle this many more will be spawned up to the maximum
2584 configured. A minimum setting of 1 is required.
2588 The number of requests each certificate validator helper can handle in
2589 parallel. Defaults to 0 which indicates the certficate validator
2590 is a old-style single threaded redirector.
2592 When this directive is set to a value >= 1 then the protocol
2593 used to communicate with the helper is modified to include
2594 a request ID in front of the request/response. The request
2595 ID from the request must be echoed back with the response
2598 You must have at least one ssl_crt_validator process.
2602 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2603 -----------------------------------------------------------------------------
2611 To specify other caches in a hierarchy, use the format:
2613 cache_peer hostname type http-port icp-port [options]
2618 # hostname type port port options
2619 # -------------------- -------- ----- ----- -----------
2620 cache_peer parent.foo.net parent 3128 3130 default
2621 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2622 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2623 cache_peer example.com parent 80 0 default
2624 cache_peer cdn.example.com sibling 3128 0
2626 type: either 'parent', 'sibling', or 'multicast'.
2628 proxy-port: The port number where the peer accept HTTP requests.
2629 For other Squid proxies this is usually 3128
2630 For web servers this is usually 80
2632 icp-port: Used for querying neighbor caches about objects.
2633 Set to 0 if the peer does not support ICP or HTCP.
2634 See ICP and HTCP options below for additional details.
2637 ==== ICP OPTIONS ====
2639 You MUST also set icp_port and icp_access explicitly when using these options.
2640 The defaults will prevent peer traffic using ICP.
2643 no-query Disable ICP queries to this neighbor.
2646 Indicates the named peer is a member of a multicast group.
2647 ICP queries will not be sent directly to the peer, but ICP
2648 replies will be accepted from it.
2650 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2651 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2654 To only send ICP queries to this neighbor infrequently.
2655 This is used to keep the neighbor round trip time updated
2656 and is usually used in conjunction with weighted-round-robin.
2659 ==== HTCP OPTIONS ====
2661 You MUST also set htcp_port and htcp_access explicitly when using these options.
2662 The defaults will prevent peer traffic using HTCP.
2665 htcp Send HTCP, instead of ICP, queries to the neighbor.
2666 You probably also want to set the "icp-port" to 4827
2667 instead of 3130. This directive accepts a comma separated
2668 list of options described below.
2670 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2672 htcp=no-clr Send HTCP to the neighbor but without
2673 sending any CLR requests. This cannot be used with
2676 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2677 This cannot be used with no-clr.
2680 Send HTCP to the neighbor including CLRs but only when
2681 they do not result from PURGE requests.
2684 Forward any HTCP CLR requests this proxy receives to the peer.
2687 ==== PEER SELECTION METHODS ====
2689 The default peer selection method is ICP, with the first responding peer
2690 being used as source. These options can be used for better load balancing.
2693 default This is a parent cache which can be used as a "last-resort"
2694 if a peer cannot be located by any of the peer-selection methods.
2695 If specified more than once, only the first is used.
2697 round-robin Load-Balance parents which should be used in a round-robin
2698 fashion in the absence of any ICP queries.
2699 weight=N can be used to add bias.
2701 weighted-round-robin
2702 Load-Balance parents which should be used in a round-robin
2703 fashion with the frequency of each parent being based on the
2704 round trip time. Closer parents are used more often.
2705 Usually used for background-ping parents.
2706 weight=N can be used to add bias.
2708 carp Load-Balance parents which should be used as a CARP array.
2709 The requests will be distributed among the parents based on the
2710 CARP load balancing hash function based on their weight.
2712 userhash Load-balance parents based on the client proxy_auth or ident username.
2714 sourcehash Load-balance parents based on the client source IP.
2717 To be used only for cache peers of type "multicast".
2718 ALL members of this multicast group have "sibling"
2719 relationship with it, not "parent". This is to a multicast
2720 group when the requested object would be fetched only from
2721 a "parent" cache, anyway. It's useful, e.g., when
2722 configuring a pool of redundant Squid proxies, being
2723 members of the same multicast group.
2726 ==== PEER SELECTION OPTIONS ====
2728 weight=N use to affect the selection of a peer during any weighted
2729 peer-selection mechanisms.
2730 The weight must be an integer; default is 1,
2731 larger weights are favored more.
2732 This option does not affect parent selection if a peering
2733 protocol is not in use.
2735 basetime=N Specify a base amount to be subtracted from round trip
2737 It is subtracted before division by weight in calculating
2738 which parent to fectch from. If the rtt is less than the
2739 base time the rtt is set to a minimal value.
2741 ttl=N Specify a TTL to use when sending multicast ICP queries
2743 Only useful when sending to a multicast group.
2744 Because we don't accept ICP replies from random
2745 hosts, you must configure other group members as
2746 peers with the 'multicast-responder' option.
2748 no-delay To prevent access to this neighbor from influencing the
2751 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2752 enabled) for this host from the specified URL rather
2753 than the Squid default location.
2756 ==== CARP OPTIONS ====
2758 carp-key=key-specification
2759 use a different key than the full URL to hash against the peer.
2760 the key-specification is a comma-separated list of the keywords
2761 scheme, host, port, path, params
2762 Order is not important.
2764 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2766 originserver Causes this parent to be contacted as an origin server.
2767 Meant to be used in accelerator setups when the peer
2771 Set the Host header of requests forwarded to this peer.
2772 Useful in accelerator setups where the server (peer)
2773 expects a certain domain name but clients may request
2774 others. ie example.com or www.example.com
2776 no-digest Disable request of cache digests.
2779 Disables requesting ICMP RTT database (NetDB).
2782 ==== AUTHENTICATION OPTIONS ====
2785 If this is a personal/workgroup proxy and your parent
2786 requires proxy authentication.
2788 Note: The string can include URL escapes (i.e. %20 for
2789 spaces). This also means % must be written as %%.
2792 Send login details received from client to this peer.
2793 Both Proxy- and WWW-Authorization headers are passed
2794 without alteration to the peer.
2795 Authentication is not required by Squid for this to work.
2797 Note: This will pass any form of authentication but
2798 only Basic auth will work through a proxy unless the
2799 connection-auth options are also used.
2801 login=PASS Send login details received from client to this peer.
2802 Authentication is not required by this option.
2804 If there are no client-provided authentication headers
2805 to pass on, but username and password are available
2806 from an external ACL user= and password= result tags
2807 they may be sent instead.
2809 Note: To combine this with proxy_auth both proxies must
2810 share the same user database as HTTP only allows for
2811 a single login (one for proxy, one for origin server).
2812 Also be warned this will expose your users proxy
2813 password to the peer. USE WITH CAUTION
2816 Send the username to the upstream cache, but with a
2817 fixed password. This is meant to be used when the peer
2818 is in another administrative domain, but it is still
2819 needed to identify each user.
2820 The star can optionally be followed by some extra
2821 information which is added to the username. This can
2822 be used to identify this proxy to the peer, similar to
2823 the login=username:password option above.
2826 If this is a personal/workgroup proxy and your parent
2827 requires a secure proxy authentication.
2828 The first principal from the default keytab or defined by
2829 the environment variable KRB5_KTNAME will be used.
2831 WARNING: The connection may transmit requests from multiple
2832 clients. Negotiate often assumes end-to-end authentication
2833 and a single-client. Which is not strictly true here.
2835 login=NEGOTIATE:principal_name
2836 If this is a personal/workgroup proxy and your parent
2837 requires a secure proxy authentication.
2838 The principal principal_name from the default keytab or
2839 defined by the environment variable KRB5_KTNAME will be
2842 WARNING: The connection may transmit requests from multiple
2843 clients. Negotiate often assumes end-to-end authentication
2844 and a single-client. Which is not strictly true here.
2846 connection-auth=on|off
2847 Tell Squid that this peer does or not support Microsoft
2848 connection oriented authentication, and any such
2849 challenges received from there should be ignored.
2850 Default is auto to automatically determine the status
2854 ==== SSL / HTTPS / TLS OPTIONS ====
2856 ssl Encrypt connections to this peer with SSL/TLS.
2858 sslcert=/path/to/ssl/certificate
2859 A client SSL certificate to use when connecting to
2862 sslkey=/path/to/ssl/key
2863 The private SSL key corresponding to sslcert above.
2864 If 'sslkey' is not specified 'sslcert' is assumed to
2865 reference a combined file containing both the
2866 certificate and the key.
2868 sslversion=1|2|3|4|5|6
2869 The SSL version to use when connecting to this peer
2870 1 = automatic (default)
2877 sslcipher=... The list of valid SSL ciphers to use when connecting
2880 ssloptions=... Specify various SSL implementation options:
2882 NO_SSLv2 Disallow the use of SSLv2
2883 NO_SSLv3 Disallow the use of SSLv3
2884 NO_TLSv1 Disallow the use of TLSv1.0
2885 NO_TLSv1_1 Disallow the use of TLSv1.1
2886 NO_TLSv1_2 Disallow the use of TLSv1.2
2888 Always create a new key when using
2889 temporary/ephemeral DH key exchanges
2890 ALL Enable various bug workarounds
2891 suggested as "harmless" by OpenSSL
2892 Be warned that this reduces SSL/TLS
2893 strength to some attacks.
2895 See the OpenSSL SSL_CTX_set_options documentation for a
2898 sslcafile=... A file containing additional CA certificates to use
2899 when verifying the peer certificate.
2901 sslcapath=... A directory containing additional CA certificates to
2902 use when verifying the peer certificate.
2904 sslcrlfile=... A certificate revocation list file to use when
2905 verifying the peer certificate.
2907 sslflags=... Specify various flags modifying the SSL implementation:
2910 Accept certificates even if they fail to
2913 Don't use the default CA list built in
2916 Don't verify the peer certificate
2917 matches the server name
2919 ssldomain= The peer name as advertised in it's certificate.
2920 Used for verifying the correctness of the received peer
2921 certificate. If not specified the peer hostname will be
2925 Enable the "Front-End-Https: On" header needed when
2926 using Squid as a SSL frontend in front of Microsoft OWA.
2927 See MS KB document Q307347 for details on this header.
2928 If set to auto the header will only be added if the
2929 request is forwarded as a https:// URL.
2932 ==== GENERAL OPTIONS ====
2935 A peer-specific connect timeout.
2936 Also see the peer_connect_timeout directive.
2938 connect-fail-limit=N
2939 How many times connecting to a peer must fail before
2940 it is marked as down. Default is 10.
2942 allow-miss Disable Squid's use of only-if-cached when forwarding
2943 requests to siblings. This is primarily useful when
2944 icp_hit_stale is used by the sibling. To extensive use
2945 of this option may result in forwarding loops, and you
2946 should avoid having two-way peerings with this option.
2947 For example to deny peer usage on requests from peer
2948 by denying cache_peer_access if the source is a peer.
2950 max-conn=N Limit the amount of connections Squid may open to this
2953 name=xxx Unique name for the peer.
2954 Required if you have multiple peers on the same host
2955 but different ports.
2956 This name can be used in cache_peer_access and similar
2957 directives to dentify the peer.
2958 Can be used by outgoing access controls through the
2961 no-tproxy Do not use the client-spoof TPROXY support when forwarding
2962 requests to this peer. Use normal address selection instead.
2964 proxy-only objects fetched from the peer will not be stored locally.
2968 NAME: cache_peer_domain cache_host_domain
2973 Use to limit the domains for which a neighbor cache will be
2977 cache_peer_domain cache-host domain [domain ...]
2978 cache_peer_domain cache-host !domain
2980 For example, specifying
2982 cache_peer_domain parent.foo.net .edu
2984 has the effect such that UDP query packets are sent to
2985 'bigserver' only when the requested object exists on a
2986 server in the .edu domain. Prefixing the domainname
2987 with '!' means the cache will be queried for objects
2990 NOTE: * Any number of domains may be given for a cache-host,
2991 either on the same or separate lines.
2992 * When multiple domains are given for a particular
2993 cache-host, the first matched domain is applied.
2994 * Cache hosts with no domain restrictions are queried
2996 * There are no defaults.
2997 * There is also a 'cache_peer_access' tag in the ACL
3001 NAME: cache_peer_access
3006 Similar to 'cache_peer_domain' but provides more flexibility by
3010 cache_peer_access cache-host allow|deny [!]aclname ...
3012 The syntax is identical to 'http_access' and the other lists of
3013 ACL elements. See the comments for 'http_access' below, or
3014 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
3017 NAME: neighbor_type_domain
3018 TYPE: hostdomaintype
3020 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3023 Modify the cache_peer neighbor type when passing requests
3024 about specific domains to the peer.
3027 neighbor_type_domain neighbor parent|sibling domain domain ...
3030 cache_peer foo.example.com parent 3128 3130
3031 neighbor_type_domain foo.example.com sibling .au .de
3033 The above configuration treats all requests to foo.example.com as a
3034 parent proxy unless the request is for a .au or .de ccTLD domain name.
3037 NAME: dead_peer_timeout
3041 LOC: Config.Timeout.deadPeer
3043 This controls how long Squid waits to declare a peer cache
3044 as "dead." If there are no ICP replies received in this
3045 amount of time, Squid will declare the peer dead and not
3046 expect to receive any further ICP replies. However, it
3047 continues to send ICP queries, and will mark the peer as
3048 alive upon receipt of the first subsequent ICP reply.
3050 This timeout also affects when Squid expects to receive ICP
3051 replies from peers. If more than 'dead_peer' seconds have
3052 passed since the last ICP reply was received, Squid will not
3053 expect to receive an ICP reply on the next query. Thus, if
3054 your time between requests is greater than this timeout, you
3055 will see a lot of requests sent DIRECT to origin servers
3056 instead of to your parents.
3059 NAME: forward_max_tries
3062 LOC: Config.forward_max_tries
3064 Controls how many different forward paths Squid will try
3065 before giving up. See also forward_timeout.
3067 NOTE: connect_retries (default: none) can make each of these
3068 possible forwarding paths be tried multiple times.
3071 NAME: hierarchy_stoplist
3074 LOC: Config.hierarchy_stoplist
3076 A list of words which, if found in a URL, cause the object to
3077 be handled directly by this cache. In other words, use this
3078 to not query neighbor caches for certain objects. You may
3079 list this option multiple times.
3082 hierarchy_stoplist cgi-bin ?
3084 Note: never_direct overrides this option.
3088 MEMORY CACHE OPTIONS
3089 -----------------------------------------------------------------------------
3096 LOC: Config.memMaxSize
3098 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3099 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3100 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3101 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3103 'cache_mem' specifies the ideal amount of memory to be used
3105 * In-Transit objects
3107 * Negative-Cached objects
3109 Data for these objects are stored in 4 KB blocks. This
3110 parameter specifies the ideal upper limit on the total size of
3111 4 KB blocks allocated. In-Transit objects take the highest
3114 In-transit objects have priority over the others. When
3115 additional space is needed for incoming data, negative-cached
3116 and hot objects will be released. In other words, the
3117 negative-cached and hot objects will fill up any unused space
3118 not needed for in-transit objects.
3120 If circumstances require, this limit will be exceeded.
3121 Specifically, if your incoming request rate requires more than
3122 'cache_mem' of memory to hold in-transit objects, Squid will
3123 exceed this limit to satisfy the new requests. When the load
3124 decreases, blocks will be freed until the high-water mark is
3125 reached. Thereafter, blocks will be used to store hot
3128 If shared memory caching is enabled, Squid does not use the shared
3129 cache space for in-transit objects, but they still consume as much
3130 local memory as they need. For more details about the shared memory
3131 cache, see memory_cache_shared.
3134 NAME: maximum_object_size_in_memory
3138 LOC: Config.Store.maxInMemObjSize
3140 Objects greater than this size will not be attempted to kept in
3141 the memory cache. This should be set high enough to keep objects
3142 accessed frequently in memory to improve performance whilst low
3143 enough to keep larger objects from hoarding cache_mem.
3146 NAME: memory_cache_shared
3149 LOC: Config.memShared
3151 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3153 Controls whether the memory cache is shared among SMP workers.
3155 The shared memory cache is meant to occupy cache_mem bytes and replace
3156 the non-shared memory cache, although some entities may still be
3157 cached locally by workers for now (e.g., internal and in-transit
3158 objects may be served from a local memory cache even if shared memory
3159 caching is enabled).
3161 By default, the memory cache is shared if and only if all of the
3162 following conditions are satisfied: Squid runs in SMP mode with
3163 multiple workers, cache_mem is positive, and Squid environment
3164 supports required IPC primitives (e.g., POSIX shared memory segments
3165 and GCC-style atomic operations).
3167 To avoid blocking locks, shared memory uses opportunistic algorithms
3168 that do not guarantee that every cachable entity that could have been
3169 shared among SMP workers will actually be shared.
3171 Currently, entities exceeding 32KB in size cannot be shared.
3174 NAME: memory_cache_mode
3178 DEFAULT_DOC: Keep the most recently fetched objects in memory
3180 Controls which objects to keep in the memory cache (cache_mem)
3182 always Keep most recently fetched objects in memory (default)
3184 disk Only disk cache hits are kept in memory, which means
3185 an object must first be cached on disk and then hit
3186 a second time before cached in memory.
3188 network Only objects fetched from network is kept in memory
3191 NAME: memory_replacement_policy
3193 LOC: Config.memPolicy
3196 The memory replacement policy parameter determines which
3197 objects are purged from memory when memory space is needed.
3199 See cache_replacement_policy for details on algorithms.
3204 -----------------------------------------------------------------------------
3207 NAME: cache_replacement_policy
3209 LOC: Config.replPolicy
3212 The cache replacement policy parameter determines which
3213 objects are evicted (replaced) when disk space is needed.
3215 lru : Squid's original list based LRU policy
3216 heap GDSF : Greedy-Dual Size Frequency
3217 heap LFUDA: Least Frequently Used with Dynamic Aging
3218 heap LRU : LRU policy implemented using a heap
3220 Applies to any cache_dir lines listed below this directive.
3222 The LRU policies keeps recently referenced objects.
3224 The heap GDSF policy optimizes object hit rate by keeping smaller
3225 popular objects in cache so it has a better chance of getting a
3226 hit. It achieves a lower byte hit rate than LFUDA though since
3227 it evicts larger (possibly popular) objects.
3229 The heap LFUDA policy keeps popular objects in cache regardless of
3230 their size and thus optimizes byte hit rate at the expense of
3231 hit rate since one large, popular object will prevent many
3232 smaller, slightly less popular objects from being cached.
3234 Both policies utilize a dynamic aging mechanism that prevents
3235 cache pollution that can otherwise occur with frequency-based
3236 replacement policies.
3238 NOTE: if using the LFUDA replacement policy you should increase
3239 the value of maximum_object_size above its default of 4 MB to
3240 to maximize the potential byte hit rate improvement of LFUDA.
3242 For more information about the GDSF and LFUDA cache replacement
3243 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3244 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3250 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3251 LOC: Config.cacheSwap
3254 cache_dir Type Directory-Name Fs-specific-data [options]
3256 You can specify multiple cache_dir lines to spread the
3257 cache among different disk partitions.
3259 Type specifies the kind of storage system to use. Only "ufs"
3260 is built by default. To enable any of the other storage systems
3261 see the --enable-storeio configure option.
3263 'Directory' is a top-level directory where cache swap
3264 files will be stored. If you want to use an entire disk
3265 for caching, this can be the mount-point directory.
3266 The directory must exist and be writable by the Squid
3267 process. Squid will NOT create this directory for you.
3269 In SMP configurations, cache_dir must not precede the workers option
3270 and should use configuration macros or conditionals to give each
3271 worker interested in disk caching a dedicated cache directory.
3274 ==== The ufs store type ====
3276 "ufs" is the old well-known Squid storage format that has always
3280 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3282 'Mbytes' is the amount of disk space (MB) to use under this
3283 directory. The default is 100 MB. Change this to suit your
3284 configuration. Do NOT put the size of your disk drive here.
3285 Instead, if you want Squid to use the entire disk drive,
3286 subtract 20% and use that value.
3288 'L1' is the number of first-level subdirectories which
3289 will be created under the 'Directory'. The default is 16.
3291 'L2' is the number of second-level subdirectories which
3292 will be created under each first-level directory. The default
3296 ==== The aufs store type ====
3298 "aufs" uses the same storage format as "ufs", utilizing
3299 POSIX-threads to avoid blocking the main Squid process on
3300 disk-I/O. This was formerly known in Squid as async-io.
3303 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3305 see argument descriptions under ufs above
3308 ==== The diskd store type ====
3310 "diskd" uses the same storage format as "ufs", utilizing a
3311 separate process to avoid blocking the main Squid process on
3315 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3317 see argument descriptions under ufs above
3319 Q1 specifies the number of unacknowledged I/O requests when Squid
3320 stops opening new files. If this many messages are in the queues,
3321 Squid won't open new files. Default is 64
3323 Q2 specifies the number of unacknowledged messages when Squid
3324 starts blocking. If this many messages are in the queues,
3325 Squid blocks until it receives some replies. Default is 72
3327 When Q1 < Q2 (the default), the cache directory is optimized
3328 for lower response time at the expense of a decrease in hit
3329 ratio. If Q1 > Q2, the cache directory is optimized for
3330 higher hit ratio at the expense of an increase in response
3334 ==== The rock store type ====
3337 cache_dir rock Directory-Name Mbytes <max-size=bytes> [options]
3339 The Rock Store type is a database-style storage. All cached
3340 entries are stored in a "database" file, using fixed-size slots,
3341 one entry per slot. The database size is specified in MB. The
3342 slot size is specified in bytes using the max-size option. See
3343 below for more info on the max-size option.
3345 If possible, Squid using Rock Store creates a dedicated kid
3346 process called "disker" to avoid blocking Squid worker(s) on disk
3347 I/O. One disker kid is created for each rock cache_dir. Diskers
3348 are created only when Squid, running in daemon mode, has support
3349 for the IpcIo disk I/O module.
3351 swap-timeout=msec: Squid will not start writing a miss to or
3352 reading a hit from disk if it estimates that the swap operation
3353 will take more than the specified number of milliseconds. By
3354 default and when set to zero, disables the disk I/O time limit
3355 enforcement. Ignored when using blocking I/O module because
3356 blocking synchronous I/O does not allow Squid to estimate the
3357 expected swap wait time.
3359 max-swap-rate=swaps/sec: Artificially limits disk access using
3360 the specified I/O rate limit. Swap out requests that
3361 would cause the average I/O rate to exceed the limit are
3362 delayed. Individual swap in requests (i.e., hits or reads) are
3363 not delayed, but they do contribute to measured swap rate and
3364 since they are placed in the same FIFO queue as swap out
3365 requests, they may wait longer if max-swap-rate is smaller.
3366 This is necessary on file systems that buffer "too
3367 many" writes and then start blocking Squid and other processes
3368 while committing those writes to disk. Usually used together
3369 with swap-timeout to avoid excessive delays and queue overflows
3370 when disk demand exceeds available disk "bandwidth". By default
3371 and when set to zero, disables the disk I/O rate limit
3372 enforcement. Currently supported by IpcIo module only.
3375 ==== The coss store type ====
3377 NP: COSS filesystem in Squid-3 has been deemed too unstable for
3378 production use and has thus been removed from this release.
3379 We hope that it can be made usable again soon.
3381 block-size=n defines the "block size" for COSS cache_dir's.
3382 Squid uses file numbers as block numbers. Since file numbers
3383 are limited to 24 bits, the block size determines the maximum
3384 size of the COSS partition. The default is 512 bytes, which
3385 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
3386 you should not change the coss block size after Squid
3387 has written some objects to the cache_dir.
3389 The coss file store has changed from 2.5. Now it uses a file
3390 called 'stripe' in the directory names in the config - and
3391 this will be created by squid -z.
3394 ==== COMMON OPTIONS ====
3396 no-store no new objects should be stored to this cache_dir.
3398 min-size=n the minimum object size in bytes this cache_dir
3399 will accept. It's used to restrict a cache_dir
3400 to only store large objects (e.g. AUFS) while
3401 other stores are optimized for smaller objects
3405 max-size=n the maximum object size in bytes this cache_dir
3407 The value in maximum_object_size directive, sets
3408 a default unless more specific details are available
3409 about the cache_dir (ie a small store capacity).
3411 Note: To make optimal use of the max-size limits you should order
3412 the cache_dir lines with the smallest max-size value first.
3414 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
3415 which can be changed with the --with-coss-membuf-size=N configure
3420 # Uncomment and adjust the following to add a disk cache directory.
3421 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3425 NAME: store_dir_select_algorithm
3427 LOC: Config.store_dir_select_algorithm
3430 How Squid selects which cache_dir to use when the response
3431 object will fit into more than one.
3433 Regardless of which algorithm is used the cache_dir min-size
3434 and max-size parameters are obeyed. As such they can affect
3435 the selection algorithm by limiting the set of considered
3442 This algorithm is suited to caches with similar cache_dir
3443 sizes and disk speeds.
3445 The disk with the least I/O pending is selected.
3446 When there are multiple disks with the same I/O load ranking
3447 the cache_dir with most available capacity is selected.
3449 When a mix of cache_dir sizes are configured the faster disks
3450 have a naturally lower I/O loading and larger disks have more
3451 capacity. So space used to store objects and data throughput
3452 may be very unbalanced towards larger disks.
3457 This algorithm is suited to caches with unequal cache_dir
3460 Each cache_dir is selected in a rotation. The next suitable
3463 Available cache_dir capacity is only considered in relation
3464 to whether the object will fit and meets the min-size and
3465 max-size parameters.
3467 Disk I/O loading is only considered to prevent overload on slow
3468 disks. This algorithm does not spread objects by size, so any
3469 I/O loading per-disk may appear very unbalanced and volatile.
3473 NAME: max_open_disk_fds
3475 LOC: Config.max_open_disk_fds
3477 DEFAULT_DOC: no limit
3479 To avoid having disk as the I/O bottleneck Squid can optionally
3480 bypass the on-disk cache if more than this amount of disk file
3481 descriptors are open.
3483 A value of 0 indicates no limit.
3486 NAME: minimum_object_size
3490 DEFAULT_DOC: no limit
3491 LOC: Config.Store.minObjectSize
3493 Objects smaller than this size will NOT be saved on disk. The
3494 value is specified in bytes, and the default is 0 KB, which
3495 means all responses can be stored.
3498 NAME: maximum_object_size
3502 LOC: Config.Store.maxObjectSize
3504 The default limit on size of objects stored to disk.
3505 This size is used for cache_dir where max-size is not set.
3506 The value is specified in bytes, and the default is 4 MB.
3508 If you wish to get a high BYTES hit ratio, you should probably
3509 increase this (one 32 MB object hit counts for 3200 10KB
3512 If you wish to increase hit ratio more than you want to
3513 save bandwidth you should leave this low.
3515 NOTE: if using the LFUDA replacement policy you should increase
3516 this value to maximize the byte hit rate improvement of LFUDA!
3517 See replacement_policy below for a discussion of this policy.
3520 NAME: cache_swap_low
3521 COMMENT: (percent, 0-100)
3524 LOC: Config.Swap.lowWaterMark
3526 The low-water mark for cache object replacement.
3527 Replacement begins when the swap (disk) usage is above the
3528 low-water mark and attempts to maintain utilization near the
3529 low-water mark. As swap utilization gets close to high-water
3530 mark object eviction becomes more aggressive. If utilization is
3531 close to the low-water mark less replacement is done each time.
3533 Defaults are 90% and 95%. If you have a large cache, 5% could be
3534 hundreds of MB. If this is the case you may wish to set these
3535 numbers closer together.
3537 See also cache_swap_high
3540 NAME: cache_swap_high
3541 COMMENT: (percent, 0-100)
3544 LOC: Config.Swap.highWaterMark
3546 The high-water mark for cache object replacement.
3547 Replacement begins when the swap (disk) usage is above the
3548 low-water mark and attempts to maintain utilization near the
3549 low-water mark. As swap utilization gets close to high-water
3550 mark object eviction becomes more aggressive. If utilization is
3551 close to the low-water mark less replacement is done each time.
3553 Defaults are 90% and 95%. If you have a large cache, 5% could be
3554 hundreds of MB. If this is the case you may wish to set these
3555 numbers closer together.
3557 See also cache_swap_low
3562 -----------------------------------------------------------------------------
3569 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
3573 logformat <name> <format specification>
3575 Defines an access log format.
3577 The <format specification> is a string with embedded % format codes
3579 % format codes all follow the same basic structure where all but
3580 the formatcode is optional. Output strings are automatically escaped
3581 as required according to their context and the output format
3582 modifiers are usually not needed, but can be specified if an explicit
3583 output format is desired.
3585 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3587 " output in quoted string format
3588 [ output in squid text log format as used by log_mime_hdrs
3589 # output in URL quoted format
3594 width minimum and/or maximum field width:
3595 [width_min][.width_max]
3596 When minimum starts with 0, the field is zero-padded.
3597 String values exceeding maximum width are truncated.
3599 {arg} argument such as header name etc
3603 % a literal % character
3604 sn Unique sequence number per log line entry
3605 err_code The ID of an error response served by Squid or
3606 a similar internal error identifier.
3607 err_detail Additional err_code-dependent error information.
3608 note The meta header specified by the argument. Also
3609 logs the adaptation meta headers set by the
3610 adaptation_meta configuration parameter.
3611 If no argument given all meta headers logged.
3613 Connection related format codes:
3615 >a Client source IP address
3617 >p Client source port
3618 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3619 >la Local IP address the client connected to
3620 >lp Local port number the client connected to
3622 la Local listening IP address the client connection was connected to.
3623 lp Local listening port number the client connection was connected to.
3625 <a Server IP address of the last server or peer connection
3626 <A Server FQDN or peer name
3627 <p Server port number of the last server or peer connection
3628 <la Local IP address of the last server or peer connection
3629 <lp Local port number of the last server or peer connection
3631 Time related format codes:
3633 ts Seconds since epoch
3634 tu subsecond time (milliseconds)
3635 tl Local time. Optional strftime format argument
3636 default %d/%b/%Y:%H:%M:%S %z
3637 tg GMT time. Optional strftime format argument
3638 default %d/%b/%Y:%H:%M:%S %z
3639 tr Response time (milliseconds)
3640 dt Total time spent making DNS lookups (milliseconds)
3642 Access Control related format codes:
3644 et Tag returned by external acl
3645 ea Log string returned by external acl
3646 un User name (any available)
3647 ul User name from authentication
3648 ue User name from external acl helper
3649 ui User name from ident
3650 us User name from SSL
3652 HTTP related format codes:
3654 [http::]>h Original received request header.
3655 Usually differs from the request header sent by
3656 Squid, although most fields are often preserved.
3657 Accepts optional header field name/value filter
3658 argument using name[:[separator]element] format.
3659 [http::]>ha Received request header after adaptation and
3660 redirection (pre-cache REQMOD vectoring point).
3661 Usually differs from the request header sent by
3662 Squid, although most fields are often preserved.
3663 Optional header name argument as for >h
3664 [http::]<h Reply header. Optional header name argument
3666 [http::]>Hs HTTP status code sent to the client
3667 [http::]<Hs HTTP status code received from the next hop
3668 [http::]<bs Number of HTTP-equivalent message body bytes
3669 received from the next hop, excluding chunked
3670 transfer encoding and control messages.
3671 Generated FTP/Gopher listings are treated as
3673 [http::]mt MIME content type
3674 [http::]rm Request method (GET/POST etc)
3675 [http::]>rm Request method from client
3676 [http::]<rm Request method sent to server or peer
3677 [http::]ru Request URL from client (historic, filtered for logging)
3678 [http::]>ru Request URL from client
3679 [http::]<ru Request URL sent to server or peer
3680 [http::]rp Request URL-Path excluding hostname
3681 [http::]>rp Request URL-Path excluding hostname from client
3682 [http::]<rp Request URL-Path excluding hostname sento to server or peer
3683 [http::]rv Request protocol version
3684 [http::]>rv Request protocol version from client
3685 [http::]<rv Request protocol version sent to server or peer
3686 [http::]<st Sent reply size including HTTP headers
3687 [http::]>st Received request size including HTTP headers. In the
3688 case of chunked requests the chunked encoding metadata
3690 [http::]>sh Received HTTP request headers size
3691 [http::]<sh Sent HTTP reply headers size
3692 [http::]st Request+Reply size including HTTP headers
3693 [http::]<sH Reply high offset sent
3694 [http::]<sS Upstream object size
3695 [http::]<pt Peer response time in milliseconds. The timer starts
3696 when the last request byte is sent to the next hop
3697 and stops when the last response byte is received.
3698 [http::]<tt Total server-side time in milliseconds. The timer
3699 starts with the first connect request (or write I/O)
3700 sent to the first selected peer. The timer stops
3701 with the last I/O with the last peer.
3703 Squid handling related format codes:
3705 Ss Squid request status (TCP_MISS etc)
3706 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3708 SSL-related format codes:
3710 ssl::bump_mode SslBump decision for the transaction:
3712 For CONNECT requests that initiated bumping of
3713 a connection and for any request received on
3714 an already bumped connection, Squid logs the
3715 corresponding SslBump mode ("server-first" or
3716 "client-first"). See the ssl_bump option for
3717 more information about these modes.
3719 A "none" token is logged for requests that
3720 triggered "ssl_bump" ACL evaluation matching
3721 either a "none" rule or no rules at all.
3723 In all other cases, a single dash ("-") is
3726 If ICAP is enabled, the following code becomes available (as
3727 well as ICAP log codes documented with the icap_log option):
3729 icap::tt Total ICAP processing time for the HTTP
3730 transaction. The timer ticks when ICAP
3731 ACLs are checked and when ICAP
3732 transaction is in progress.
3734 If adaptation is enabled the following three codes become available:
3736 adapt::<last_h The header of the last ICAP response or
3737 meta-information from the last eCAP
3738 transaction related to the HTTP transaction.
3739 Like <h, accepts an optional header name
3742 adapt::sum_trs Summed adaptation transaction response
3743 times recorded as a comma-separated list in
3744 the order of transaction start time. Each time
3745 value is recorded as an integer number,
3746 representing response time of one or more
3747 adaptation (ICAP or eCAP) transaction in
3748 milliseconds. When a failed transaction is
3749 being retried or repeated, its time is not
3750 logged individually but added to the
3751 replacement (next) transaction. See also:
3754 adapt::all_trs All adaptation transaction response times.
3755 Same as adaptation_strs but response times of
3756 individual transactions are never added
3757 together. Instead, all transaction response
3758 times are recorded individually.
3760 You can prefix adapt::*_trs format codes with adaptation
3761 service name in curly braces to record response time(s) specific
3762 to that service. For example: %{my_service}adapt::sum_trs
3764 If SSL is enabled, the following formating codes become available:
3766 %ssl::>cert_subject The Subject field of the received client
3767 SSL certificate or a dash ('-') if Squid has
3768 received an invalid/malformed certificate or
3769 no certificate at all. Consider encoding the
3770 logged value because Subject often has spaces.
3772 %ssl::>cert_issuer The Issuer field of the received client
3773 SSL certificate or a dash ('-') if Squid has
3774 received an invalid/malformed certificate or
3775 no certificate at all. Consider encoding the
3776 logged value because Issuer often has spaces.
3778 The default formats available (which do not need re-defining) are:
3780 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3781 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3782 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3783 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3784 logformat useragent %>a [%tl] "%{User-Agent}>h"
3786 NOTE: When the log_mime_hdrs directive is set to ON.
3787 The squid, common and combined formats have a safely encoded copy
3788 of the mime headers appended to each line within a pair of brackets.
3790 NOTE: The common and combined formats are not quite true to the Apache definition.
3791 The logs from Squid contain an extra status and hierarchy code appended.
3795 NAME: access_log cache_access_log
3797 LOC: Config.Log.accesslogs
3798 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3800 Configures whether and how Squid logs HTTP and ICP transactions.
3801 If access logging is enabled, a single line is logged for every
3802 matching HTTP or ICP request. The recommended directive formats are:
3804 access_log <module>:<place> [option ...] [acl acl ...]
3805 access_log none [acl acl ...]
3807 The following directive format is accepted but may be deprecated:
3808 access_log <module>:<place> [<logformat name> [acl acl ...]]
3810 In most cases, the first ACL name must not contain the '=' character
3811 and should not be equal to an existing logformat name. You can always
3812 start with an 'all' ACL to work around those restrictions.
3814 Will log to the specified module:place using the specified format (which
3815 must be defined in a logformat directive) those entries which match
3816 ALL the acl's specified (which must be defined in acl clauses).
3817 If no acl is specified, all requests will be logged to this destination.
3819 ===== Available options for the recommended directive format =====
3821 logformat=name Names log line format (either built-in or
3822 defined by a logformat directive). Defaults
3825 buffer-size=64KB Defines approximate buffering limit for log
3826 records (see buffered_logs). Squid should not
3827 keep more than the specified size and, hence,
3828 should flush records before the buffer becomes
3829 full to avoid overflows under normal
3830 conditions (the exact flushing algorithm is
3831 module-dependent though). The on-error option
3832 controls overflow handling.
3834 on-error=die|drop Defines action on unrecoverable errors. The
3835 'drop' action ignores (i.e., does not log)
3836 affected log records. The default 'die' action
3837 kills the affected worker. The drop action
3838 support has not been tested for modules other
3841 ===== Modules Currently available =====
3843 none Do not log any requests matching these ACL.
3844 Do not specify Place or logformat name.
3846 stdio Write each log line to disk immediately at the completion of
3848 Place: the filename and path to be written.
3850 daemon Very similar to stdio. But instead of writing to disk the log
3851 line is passed to a daemon helper for asychronous handling instead.
3852 Place: varies depending on the daemon.
3854 log_file_daemon Place: the file name and path to be written.
3856 syslog To log each request via syslog facility.
3857 Place: The syslog facility and priority level for these entries.
3858 Place Format: facility.priority
3860 where facility could be any of:
3861 authpriv, daemon, local0 ... local7 or user.
3863 And priority could be any of:
3864 err, warning, notice, info, debug.
3866 udp To send each log line as text data to a UDP receiver.
3867 Place: The destination host name or IP and port.
3868 Place Format: //host:port
3870 tcp To send each log line as text data to a TCP receiver.
3871 Lines may be accumulated before sending (see buffered_logs).
3872 Place: The destination host name or IP and port.
3873 Place Format: //host:port
3876 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3882 LOC: Config.Log.icaplogs
3885 ICAP log files record ICAP transaction summaries, one line per
3888 The icap_log option format is:
3889 icap_log <filepath> [<logformat name> [acl acl ...]]
3890 icap_log none [acl acl ...]]
3892 Please see access_log option documentation for details. The two
3893 kinds of logs share the overall configuration approach and many
3896 ICAP processing of a single HTTP message or transaction may
3897 require multiple ICAP transactions. In such cases, multiple
3898 ICAP transaction log lines will correspond to a single access
3901 ICAP log uses logformat codes that make sense for an ICAP
3902 transaction. Header-related codes are applied to the HTTP header
3903 embedded in an ICAP server response, with the following caveats:
3904 For REQMOD, there is no HTTP response header unless the ICAP
3905 server performed request satisfaction. For RESPMOD, the HTTP
3906 request header is the header sent to the ICAP server. For
3907 OPTIONS, there are no HTTP headers.
3909 The following format codes are also available for ICAP logs:
3911 icap::<A ICAP server IP address. Similar to <A.
3913 icap::<service_name ICAP service name from the icap_service
3914 option in Squid configuration file.
3916 icap::ru ICAP Request-URI. Similar to ru.
3918 icap::rm ICAP request method (REQMOD, RESPMOD, or
3919 OPTIONS). Similar to existing rm.
3921 icap::>st Bytes sent to the ICAP server (TCP payload
3922 only; i.e., what Squid writes to the socket).
3924 icap::<st Bytes received from the ICAP server (TCP
3925 payload only; i.e., what Squid reads from
3928 icap::<bs Number of message body bytes received from the
3929 ICAP server. ICAP message body, if any, usually
3930 includes encapsulated HTTP message headers and
3931 possibly encapsulated HTTP message body. The
3932 HTTP body part is dechunked before its size is
3935 icap::tr Transaction response time (in
3936 milliseconds). The timer starts when
3937 the ICAP transaction is created and
3938 stops when the transaction is completed.
3941 icap::tio Transaction I/O time (in milliseconds). The
3942 timer starts when the first ICAP request
3943 byte is scheduled for sending. The timers
3944 stops when the last byte of the ICAP response
3947 icap::to Transaction outcome: ICAP_ERR* for all
3948 transaction errors, ICAP_OPT for OPTION
3949 transactions, ICAP_ECHO for 204
3950 responses, ICAP_MOD for message
3951 modification, and ICAP_SAT for request
3952 satisfaction. Similar to Ss.
3954 icap::Hs ICAP response status code. Similar to Hs.
3956 icap::>h ICAP request header(s). Similar to >h.
3958 icap::<h ICAP response header(s). Similar to <h.
3960 The default ICAP log format, which can be used without an explicit
3961 definition, is called icap_squid:
3963 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3965 See also: logformat, log_icap, and %adapt::<last_h
3968 NAME: logfile_daemon
3970 DEFAULT: @DEFAULT_LOGFILED@
3971 LOC: Log::TheConfig.logfile_daemon
3973 Specify the path to the logfile-writing daemon. This daemon is
3974 used to write the access and store logs, if configured.
3976 Squid sends a number of commands to the log daemon:
3977 L<data>\n - logfile data
3982 r<n>\n - set rotate count to <n>
3983 b<n>\n - 1 = buffer output, 0 = don't buffer output
3985 No responses is expected.
3990 LOC: Config.accessList.log
3992 DEFAULT_DOC: Allow logging for all transactions.
3993 COMMENT: allow|deny acl acl...
3995 This options allows you to control which requests gets logged
3996 to access.log (see access_log directive). Requests denied for
3997 logging will also not be accounted for in performance counters.
3999 This clause only supports fast acl types.
4000 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4006 LOC: Config.accessList.icap
4008 DEFAULT_DOC: Allow logging for all ICAP transactions.
4010 This options allows you to control which requests get logged
4011 to icap.log. See the icap_log directive for ICAP log details.
4014 NAME: cache_store_log
4017 LOC: Config.Log.store
4019 Logs the activities of the storage manager. Shows which
4020 objects are ejected from the cache, and which objects are
4021 saved and for how long.
4022 There are not really utilities to analyze this data, so you can safely
4023 disable it (the default).
4025 Store log uses modular logging outputs. See access_log for the list
4026 of modules supported.
4029 cache_store_log stdio:@DEFAULT_STORE_LOG@
4030 cache_store_log daemon:@DEFAULT_STORE_LOG@
4033 NAME: cache_swap_state cache_swap_log
4035 LOC: Config.Log.swap
4037 DEFAULT_DOC: Store the journal inside its cache_dir
4039 Location for the cache "swap.state" file. This index file holds
4040 the metadata of objects saved on disk. It is used to rebuild
4041 the cache during startup. Normally this file resides in each
4042 'cache_dir' directory, but you may specify an alternate
4043 pathname here. Note you must give a full filename, not just
4044 a directory. Since this is the index for the whole object
4045 list you CANNOT periodically rotate it!
4047 If %s can be used in the file name it will be replaced with a
4048 a representation of the cache_dir name where each / is replaced
4049 with '.'. This is needed to allow adding/removing cache_dir
4050 lines when cache_swap_log is being used.
4052 If have more than one 'cache_dir', and %s is not used in the name
4053 these swap logs will have names such as:
4059 The numbered extension (which is added automatically)
4060 corresponds to the order of the 'cache_dir' lines in this
4061 configuration file. If you change the order of the 'cache_dir'
4062 lines in this file, these index files will NOT correspond to
4063 the correct 'cache_dir' entry (unless you manually rename
4064 them). We recommend you do NOT use this option. It is
4065 better to keep these index files in each 'cache_dir' directory.
4068 NAME: logfile_rotate
4071 LOC: Config.Log.rotateNumber
4073 Specifies the number of logfile rotations to make when you
4074 type 'squid -k rotate'. The default is 10, which will rotate
4075 with extensions 0 through 9. Setting logfile_rotate to 0 will
4076 disable the file name rotation, but the logfiles are still closed
4077 and re-opened. This will enable you to rename the logfiles
4078 yourself just before sending the rotate signal.
4080 Note, the 'squid -k rotate' command normally sends a USR1
4081 signal to the running squid process. In certain situations
4082 (e.g. on Linux with Async I/O), USR1 is used for other
4083 purposes, so -k rotate uses another signal. It is best to get
4084 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4087 Note, from Squid-3.1 this option is only a default for cache.log,
4088 that log can be rotated separately by using debug_options.
4091 NAME: emulate_httpd_log
4094 Replace this with an access_log directive using the format 'common' or 'combined'.
4097 NAME: log_ip_on_direct
4100 Remove this option from your config. To log server or peer names use %<A in the log format.
4105 DEFAULT: @DEFAULT_MIME_TABLE@
4106 LOC: Config.mimeTablePathname
4108 Path to Squid's icon configuration file.
4110 You shouldn't need to change this, but the default file contains
4111 examples and formatting information if you do.
4117 LOC: Config.onoff.log_mime_hdrs
4120 The Cache can record both the request and the response MIME
4121 headers for each HTTP transaction. The headers are encoded
4122 safely and will appear as two bracketed fields at the end of
4123 the access log (for either the native or httpd-emulated log
4124 formats). To enable this logging set log_mime_hdrs to 'on'.
4130 Replace this with an access_log directive using the format 'useragent'.
4133 NAME: referer_log referrer_log
4136 Replace this with an access_log directive using the format 'referrer'.
4141 DEFAULT: @DEFAULT_PID_FILE@
4142 LOC: Config.pidFilename
4144 A filename to write the process-id to. To disable, enter "none".
4150 Remove this option from your config. To log FQDN use %>A in the log format.
4153 NAME: client_netmask
4155 LOC: Config.Addrs.client_netmask
4157 DEFAULT_DOC: Log full client IP address
4159 A netmask for client addresses in logfiles and cachemgr output.
4160 Change this to protect the privacy of your cache clients.
4161 A netmask of 255.255.255.0 will log all IP's in that range with
4162 the last digit set to '0'.
4168 Use a regular access.log with ACL limiting it to MISS events.
4171 NAME: strip_query_terms
4173 LOC: Config.onoff.strip_query_terms
4176 By default, Squid strips query terms from requested URLs before
4177 logging. This protects your user's privacy and reduces log size.
4179 When investigating HIT/MISS or other caching behaviour you
4180 will need to disable this to see the full URL used by Squid.
4187 LOC: Config.onoff.buffered_logs
4189 Whether to write/send access_log records ASAP or accumulate them and
4190 then write/send them in larger chunks. Buffering may improve
4191 performance because it decreases the number of I/Os. However,
4192 buffering increases the delay before log records become available to
4193 the final recipient (e.g., a disk file or logging daemon) and,
4194 hence, increases the risk of log records loss.
4196 Note that even when buffered_logs are off, Squid may have to buffer
4197 records if it cannot write/send them immediately due to pending I/Os
4198 (e.g., the I/O writing the previous log record) or connectivity loss.
4200 Currently honored by 'daemon' and 'tcp' access_log modules only.
4203 NAME: netdb_filename
4205 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4206 LOC: Config.netdbFilename
4209 Where Squid stores it's netdb journal.
4210 When enabled this journal preserves netdb state between restarts.
4212 To disable, enter "none".
4216 OPTIONS FOR TROUBLESHOOTING
4217 -----------------------------------------------------------------------------
4222 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4223 LOC: Debug::cache_log
4225 Squid administrative logging file.
4227 This is where general information about Squid behavior goes. You can
4228 increase the amount of data logged to this file and how often it is
4229 rotated with "debug_options"
4235 DEFAULT_DOC: Log all critical and important messages.
4236 LOC: Debug::debugOptions
4238 Logging options are set as section,level where each source file
4239 is assigned a unique section. Lower levels result in less
4240 output, Full debugging (level 9) can result in a very large
4241 log file, so be careful.
4243 The magic word "ALL" sets debugging levels for all sections.
4244 The default is to run with "ALL,1" to record important warnings.
4246 The rotate=N option can be used to keep more or less of these logs
4247 than would otherwise be kept by logfile_rotate.
4248 For most uses a single log should be enough to monitor current
4249 events affecting Squid.
4254 LOC: Config.coredump_dir
4255 DEFAULT_IF_NONE: none
4256 DEFAULT_DOC: Use the directory from where Squid was started.
4258 By default Squid leaves core files in the directory from where
4259 it was started. If you set 'coredump_dir' to a directory
4260 that exists, Squid will chdir() to that directory at startup
4261 and coredump files will be left there.
4265 # Leave coredumps in the first cache dir
4266 coredump_dir @DEFAULT_SWAP_DIR@
4272 OPTIONS FOR FTP GATEWAYING
4273 -----------------------------------------------------------------------------
4279 LOC: Config.Ftp.anon_user
4281 If you want the anonymous login password to be more informative
4282 (and enable the use of picky FTP servers), set this to something
4283 reasonable for your domain, like wwwuser@somewhere.net
4285 The reason why this is domainless by default is the
4286 request can be made on the behalf of a user in any domain,
4287 depending on how the cache is used.
4288 Some FTP server also validate the email address is valid
4289 (for example perl.com).
4295 LOC: Config.Ftp.passive
4297 If your firewall does not allow Squid to use passive
4298 connections, turn off this option.
4300 Use of ftp_epsv_all option requires this to be ON.
4306 LOC: Config.Ftp.epsv_all
4308 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4310 NATs may be able to put the connection on a "fast path" through the
4311 translator, as the EPRT command will never be used and therefore,
4312 translation of the data portion of the segments will never be needed.
4314 When a client only expects to do two-way FTP transfers this may be
4316 If squid finds that it must do a three-way FTP transfer after issuing
4317 an EPSV ALL command, the FTP session will fail.
4319 If you have any doubts about this option do not use it.
4320 Squid will nicely attempt all other connection methods.
4322 Requires ftp_passive to be ON (default) for any effect.
4328 LOC: Config.Ftp.epsv
4330 FTP Protocol extensions permit the use of a special "EPSV" command.
4332 NATs may be able to put the connection on a "fast path" through the
4333 translator using EPSV, as the EPRT command will never be used
4334 and therefore, translation of the data portion of the segments
4335 will never be needed.
4337 Turning this OFF will prevent EPSV being attempted.
4338 WARNING: Doing so will convert Squid back to the old behavior with all
4339 the related problems with external NAT devices/layers.
4341 Requires ftp_passive to be ON (default) for any effect.
4347 LOC: Config.Ftp.eprt
4349 FTP Protocol extensions permit the use of a special "EPRT" command.
4351 This extension provides a protocol neutral alternative to the
4352 IPv4-only PORT command. When supported it enables active FTP data
4353 channels over IPv6 and efficient NAT handling.
4355 Turning this OFF will prevent EPRT being attempted and will skip
4356 straight to using PORT for IPv4 servers.
4358 Some devices are known to not handle this extension correctly and
4359 may result in crashes. Devices which suport EPRT enough to fail
4360 cleanly will result in Squid attempting PORT anyway. This directive
4361 should only be disabled when EPRT results in device failures.
4363 WARNING: Doing so will convert Squid back to the old behavior with all
4364 the related problems with external NAT devices/layers and IPv4-only FTP.
4367 NAME: ftp_sanitycheck
4370 LOC: Config.Ftp.sanitycheck
4372 For security and data integrity reasons Squid by default performs
4373 sanity checks of the addresses of FTP data connections ensure the
4374 data connection is to the requested server. If you need to allow
4375 FTP connections to servers using another IP address for the data
4376 connection turn this off.
4379 NAME: ftp_telnet_protocol
4382 LOC: Config.Ftp.telnet
4384 The FTP protocol is officially defined to use the telnet protocol
4385 as transport channel for the control connection. However, many
4386 implementations are broken and does not respect this aspect of
4389 If you have trouble accessing files with ASCII code 255 in the
4390 path or similar problems involving this ASCII code you can
4391 try setting this directive to off. If that helps, report to the
4392 operator of the FTP server in question that their FTP server
4393 is broken and does not follow the FTP standard.
4397 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4398 -----------------------------------------------------------------------------
4403 DEFAULT: @DEFAULT_DISKD@
4404 LOC: Config.Program.diskd
4406 Specify the location of the diskd executable.
4407 Note this is only useful if you have compiled in
4408 diskd as one of the store io modules.
4411 NAME: unlinkd_program
4414 DEFAULT: @DEFAULT_UNLINKD@
4415 LOC: Config.Program.unlinkd
4417 Specify the location of the executable for file deletion process.
4420 NAME: pinger_program
4422 DEFAULT: @DEFAULT_PINGER@
4423 LOC: Config.pinger.program
4426 Specify the location of the executable for the pinger process.
4432 LOC: Config.pinger.enable
4435 Control whether the pinger is active at run-time.
4436 Enables turning ICMP pinger on and off with a simple
4437 squid -k reconfigure.
4442 OPTIONS FOR URL REWRITING
4443 -----------------------------------------------------------------------------
4446 NAME: url_rewrite_program redirect_program
4448 LOC: Config.Program.redirect
4451 Specify the location of the executable URL rewriter to use.
4452 Since they can perform almost any function there isn't one included.
4454 For each requested URL, the rewriter will receive on line with the format
4456 [channel-ID <SP>] URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kv-pairs]<NL>
4459 After processing the request the helper must reply using the following format:
4461 [channel-ID <SP>] result [<SP> kv-pairs]
4463 The result code can be:
4465 OK status=30N url="..."
4466 Redirect the URL to the one supplied in 'url='.
4467 'status=' is optional and contains the status code to send
4468 the client in Squids HTTP response. It must be one of the
4469 HTTP redirect status codes: 301, 302, 303, 307, 308.
4470 When no status is given Squid will use 302.
4472 OK rewrite-url="..."
4473 Rewrite the URL to the one supplied in 'rewrite-url='.
4474 The new URL is fetched directly by Squid and returned to
4475 the client as the response to its request.
4478 Do not change the URL.
4481 An internal error occurred in the helper, preventing
4482 a result being identified.
4485 In the future, the interface protocol will be extended with
4486 key=value pairs ("kv-pairs" shown above). Helper programs
4487 should be prepared to receive and possibly ignore additional
4488 whitespace-separated tokens on each input line.
4490 When using the concurrency= option the protocol is changed by
4491 introducing a query channel tag in front of the request/response.
4492 The query channel tag is a number between 0 and concurrency-1.
4493 This value must be echoed back unchanged to Squid as the first part
4494 of the response relating to its request.
4496 WARNING: URL re-writing ability should be avoided whenever possible.
4497 Use the URL redirect form of response instead.
4499 Re-write creates a difference in the state held by the client
4500 and server. Possibly causing confusion when the server response
4501 contains snippets of its view state. Embeded URLs, response
4502 and content Location headers, etc. are not re-written by this
4505 By default, a URL rewriter is not used.
4508 NAME: url_rewrite_children redirect_children
4509 TYPE: HelperChildConfig
4510 DEFAULT: 20 startup=0 idle=1 concurrency=0
4511 LOC: Config.redirectChildren
4513 The maximum number of redirector processes to spawn. If you limit
4514 it too few Squid will have to wait for them to process a backlog of
4515 URLs, slowing it down. If you allow too many they will use RAM
4516 and other system resources noticably.
4518 The startup= and idle= options allow some measure of skew in your
4523 Sets a minimum of how many processes are to be spawned when Squid
4524 starts or reconfigures. When set to zero the first request will
4525 cause spawning of the first child process to handle it.
4527 Starting too few will cause an initial slowdown in traffic as Squid
4528 attempts to simultaneously spawn enough processes to cope.
4532 Sets a minimum of how many processes Squid is to try and keep available
4533 at all times. When traffic begins to rise above what the existing
4534 processes can handle this many more will be spawned up to the maximum
4535 configured. A minimum setting of 1 is required.
4539 The number of requests each redirector helper can handle in
4540 parallel. Defaults to 0 which indicates the redirector
4541 is a old-style single threaded redirector.
4543 When this directive is set to a value >= 1 then the protocol
4544 used to communicate with the helper is modified to include
4545 an ID in front of the request/response. The ID from the request
4546 must be echoed back with the response to that request.
4549 NAME: url_rewrite_host_header redirect_rewrites_host_header
4552 LOC: Config.onoff.redir_rewrites_host
4554 To preserve same-origin security policies in browsers and
4555 prevent Host: header forgery by redirectors Squid rewrites
4556 any Host: header in redirected requests.
4558 If you are running an accelerator this may not be a wanted
4559 effect of a redirector. This directive enables you disable
4560 Host: alteration in reverse-proxy traffic.
4562 WARNING: Entries are cached on the result of the URL rewriting
4563 process, so be careful if you have domain-virtual hosts.
4565 WARNING: Squid and other software verifies the URL and Host
4566 are matching, so be careful not to relay through other proxies
4567 or inspecting firewalls with this disabled.
4570 NAME: url_rewrite_access redirector_access
4573 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4574 LOC: Config.accessList.redirector
4576 If defined, this access list specifies which requests are
4577 sent to the redirector processes.
4579 This clause supports both fast and slow acl types.
4580 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4583 NAME: url_rewrite_bypass redirector_bypass
4585 LOC: Config.onoff.redirector_bypass
4588 When this is 'on', a request will not go through the
4589 redirector if all the helpers are busy. If this is 'off'
4590 and the redirector queue grows too large, Squid will exit
4591 with a FATAL error and ask you to increase the number of
4592 redirectors. You should only enable this if the redirectors
4593 are not critical to your caching system. If you use
4594 redirectors for access control, and you enable this option,
4595 users may have access to pages they should not
4596 be allowed to request.
4600 OPTIONS FOR STORE ID
4601 -----------------------------------------------------------------------------
4604 NAME: store_id_program storeurl_rewrite_program
4606 LOC: Config.Program.store_id
4609 Specify the location of the executable StoreID helper to use.
4610 Since they can perform almost any function there isn't one included.
4612 For each requested URL, the helper will receive one line with the format
4614 [channel-ID <SP>] URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kv-pairs]<NL>
4617 After processing the request the helper must reply using the following format:
4619 [channel-ID <SP>] result [<SP> kv-pairs]
4621 The result code can be:
4624 Use the StoreID supplied in 'store-id='.
4627 The default is to use HTTP request URL as the store ID.
4630 An internal error occured in the helper, preventing
4631 a result being identified.
4634 Helper programs should be prepared to receive and possibly ignore additional
4635 kv-pairs with keys they do not support.
4637 When using the concurrency= option the protocol is changed by
4638 introducing a query channel tag in front of the request/response.
4639 The query channel tag is a number between 0 and concurrency-1.
4640 This value must be echoed back unchanged to Squid as the first part
4641 of the response relating to its request.
4643 NOTE: when using StoreID refresh_pattern will apply to the StoreID
4644 returned from the helper and not the URL.
4646 WARNING: Wrong StoreID value returned by a careless helper may result
4647 in the wrong cached response returned to the user.
4649 By default, a StoreID helper is not used.
4652 NAME: store_id_children storeurl_rewrite_children
4653 TYPE: HelperChildConfig
4654 DEFAULT: 20 startup=0 idle=1 concurrency=0
4655 LOC: Config.storeIdChildren
4657 The maximum number of StoreID helper processes to spawn. If you limit
4658 it too few Squid will have to wait for them to process a backlog of
4659 requests, slowing it down. If you allow too many they will use RAM
4660 and other system resources noticably.
4662 The startup= and idle= options allow some measure of skew in your
4667 Sets a minimum of how many processes are to be spawned when Squid
4668 starts or reconfigures. When set to zero the first request will
4669 cause spawning of the first child process to handle it.
4671 Starting too few will cause an initial slowdown in traffic as Squid
4672 attempts to simultaneously spawn enough processes to cope.
4676 Sets a minimum of how many processes Squid is to try and keep available
4677 at all times. When traffic begins to rise above what the existing
4678 processes can handle this many more will be spawned up to the maximum
4679 configured. A minimum setting of 1 is required.
4683 The number of requests each storeID helper can handle in
4684 parallel. Defaults to 0 which indicates the helper
4685 is a old-style single threaded program.
4687 When this directive is set to a value >= 1 then the protocol
4688 used to communicate with the helper is modified to include
4689 an ID in front of the request/response. The ID from the request
4690 must be echoed back with the response to that request.
4693 NAME: store_id_access storeurl_rewrite_access
4696 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4697 LOC: Config.accessList.store_id
4699 If defined, this access list specifies which requests are
4700 sent to the StoreID processes. By default all requests
4703 This clause supports both fast and slow acl types.
4704 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4707 NAME: store_id_bypass storeurl_rewrite_bypass
4709 LOC: Config.onoff.store_id_bypass
4712 When this is 'on', a request will not go through the
4713 helper if all helpers are busy. If this is 'off'
4714 and the helper queue grows too large, Squid will exit
4715 with a FATAL error and ask you to increase the number of
4716 helpers. You should only enable this if the helperss
4717 are not critical to your caching system. If you use
4718 helpers for critical caching components, and you enable this
4719 option, users may not get objects from cache.
4723 OPTIONS FOR TUNING THE CACHE
4724 -----------------------------------------------------------------------------
4727 NAME: cache no_cache
4730 DEFAULT_DOC: Allow caching, unless rules exist in squid.conf.
4731 LOC: Config.accessList.noCache
4733 A list of ACL elements which, if matched and denied, cause the request to
4734 not be satisfied from the cache and the reply to not be cached.
4735 In other words, use this to force certain objects to never be cached.
4737 You must use the words 'allow' or 'deny' to indicate whether items
4738 matching the ACL should be allowed or denied into the cache.
4740 This clause supports both fast and slow acl types.
4741 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4747 LOC: Config.maxStale
4750 This option puts an upper limit on how stale content Squid
4751 will serve from the cache if cache validation fails.
4752 Can be overriden by the refresh_pattern max-stale option.
4755 NAME: refresh_pattern
4756 TYPE: refreshpattern
4760 usage: refresh_pattern [-i] regex min percent max [options]
4762 By default, regular expressions are CASE-SENSITIVE. To make
4763 them case-insensitive, use the -i option.
4765 'Min' is the time (in minutes) an object without an explicit
4766 expiry time should be considered fresh. The recommended
4767 value is 0, any higher values may cause dynamic applications
4768 to be erroneously cached unless the application designer
4769 has taken the appropriate actions.
4771 'Percent' is a percentage of the objects age (time since last
4772 modification age) an object without explicit expiry time
4773 will be considered fresh.
4775 'Max' is an upper limit on how long objects without an explicit
4776 expiry time will be considered fresh.
4778 options: override-expire
4783 ignore-must-revalidate
4790 override-expire enforces min age even if the server
4791 sent an explicit expiry time (e.g., with the
4792 Expires: header or Cache-Control: max-age). Doing this
4793 VIOLATES the HTTP standard. Enabling this feature
4794 could make you liable for problems which it causes.
4796 Note: override-expire does not enforce staleness - it only extends
4797 freshness / min. If the server returns a Expires time which
4798 is longer than your max time, Squid will still consider
4799 the object fresh for that period of time.
4801 override-lastmod enforces min age even on objects
4802 that were modified recently.
4804 reload-into-ims changes client no-cache or ``reload''
4805 to If-Modified-Since requests. Doing this VIOLATES the
4806 HTTP standard. Enabling this feature could make you
4807 liable for problems which it causes.
4809 ignore-reload ignores a client no-cache or ``reload''
4810 header. Doing this VIOLATES the HTTP standard. Enabling
4811 this feature could make you liable for problems which
4814 ignore-no-store ignores any ``Cache-control: no-store''
4815 headers received from a server. Doing this VIOLATES
4816 the HTTP standard. Enabling this feature could make you
4817 liable for problems which it causes.
4819 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
4820 headers received from a server. Doing this VIOLATES
4821 the HTTP standard. Enabling this feature could make you
4822 liable for problems which it causes.
4824 ignore-private ignores any ``Cache-control: private''
4825 headers received from a server. Doing this VIOLATES
4826 the HTTP standard. Enabling this feature could make you
4827 liable for problems which it causes.
4829 ignore-auth caches responses to requests with authorization,
4830 as if the originserver had sent ``Cache-control: public''
4831 in the response header. Doing this VIOLATES the HTTP standard.
4832 Enabling this feature could make you liable for problems which
4835 refresh-ims causes squid to contact the origin server
4836 when a client issues an If-Modified-Since request. This
4837 ensures that the client will receive an updated version
4838 if one is available.
4840 store-stale stores responses even if they don't have explicit
4841 freshness or a validator (i.e., Last-Modified or an ETag)
4842 present, or if they're already stale. By default, Squid will
4843 not cache such responses because they usually can't be
4844 reused. Note that such responses will be stale by default.
4846 max-stale=NN provide a maximum staleness factor. Squid won't
4847 serve objects more stale than this even if it failed to
4848 validate the object. Default: use the max_stale global limit.
4850 Basically a cached object is:
4852 FRESH if expires < now, else STALE
4854 FRESH if lm-factor < percent, else STALE
4858 The refresh_pattern lines are checked in the order listed here.
4859 The first entry which matches is used. If none of the entries
4860 match the default will be used.
4862 Note, you must uncomment all the default lines if you want
4863 to change one. The default setting is only active if none is
4869 # Add any of your own refresh_pattern entries above these.
4871 refresh_pattern ^ftp: 1440 20% 10080
4872 refresh_pattern ^gopher: 1440 0% 1440
4873 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
4874 refresh_pattern . 0 20% 4320
4878 NAME: quick_abort_min
4882 LOC: Config.quickAbort.min
4885 NAME: quick_abort_max
4889 LOC: Config.quickAbort.max
4892 NAME: quick_abort_pct
4896 LOC: Config.quickAbort.pct
4898 The cache by default continues downloading aborted requests
4899 which are almost completed (less than 16 KB remaining). This
4900 may be undesirable on slow (e.g. SLIP) links and/or very busy
4901 caches. Impatient users may tie up file descriptors and
4902 bandwidth by repeatedly requesting and immediately aborting
4905 When the user aborts a request, Squid will check the
4906 quick_abort values to the amount of data transfered until
4909 If the transfer has less than 'quick_abort_min' KB remaining,
4910 it will finish the retrieval.
4912 If the transfer has more than 'quick_abort_max' KB remaining,
4913 it will abort the retrieval.
4915 If more than 'quick_abort_pct' of the transfer has completed,
4916 it will finish the retrieval.
4918 If you do not want any retrieval to continue after the client
4919 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
4922 If you want retrievals to always continue if they are being
4923 cached set 'quick_abort_min' to '-1 KB'.
4926 NAME: read_ahead_gap
4927 COMMENT: buffer-size
4929 LOC: Config.readAheadGap
4932 The amount of data the cache will buffer ahead of what has been
4933 sent to the client when retrieving an object from another server.
4937 IFDEF: USE_HTTP_VIOLATIONS
4940 LOC: Config.negativeTtl
4943 Set the Default Time-to-Live (TTL) for failed requests.
4944 Certain types of failures (such as "connection refused" and
4945 "404 Not Found") are able to be negatively-cached for a short time.
4946 Modern web servers should provide Expires: header, however if they
4947 do not this can provide a minimum TTL.
4948 The default is not to cache errors with unknown expiry details.
4950 Note that this is different from negative caching of DNS lookups.
4952 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4953 this feature could make you liable for problems which it
4957 NAME: positive_dns_ttl
4960 LOC: Config.positiveDnsTtl
4963 Upper limit on how long Squid will cache positive DNS responses.
4964 Default is 6 hours (360 minutes). This directive must be set
4965 larger than negative_dns_ttl.
4968 NAME: negative_dns_ttl
4971 LOC: Config.negativeDnsTtl
4974 Time-to-Live (TTL) for negative caching of failed DNS lookups.
4975 This also sets the lower cache limit on positive lookups.
4976 Minimum value is 1 second, and it is not recommendable to go
4977 much below 10 seconds.
4980 NAME: range_offset_limit
4981 COMMENT: size [acl acl...]
4983 LOC: Config.rangeOffsetLimit
4986 usage: (size) [units] [[!]aclname]
4988 Sets an upper limit on how far (number of bytes) into the file
4989 a Range request may be to cause Squid to prefetch the whole file.
4990 If beyond this limit, Squid forwards the Range request as it is and
4991 the result is NOT cached.
4993 This is to stop a far ahead range request (lets say start at 17MB)
4994 from making Squid fetch the whole object up to that point before
4995 sending anything to the client.
4997 Multiple range_offset_limit lines may be specified, and they will
4998 be searched from top to bottom on each request until a match is found.
4999 The first match found will be used. If no line matches a request, the
5000 default limit of 0 bytes will be used.
5002 'size' is the limit specified as a number of units.
5004 'units' specifies whether to use bytes, KB, MB, etc.
5005 If no units are specified bytes are assumed.
5007 A size of 0 causes Squid to never fetch more than the
5008 client requested. (default)
5010 A size of 'none' causes Squid to always fetch the object from the
5011 beginning so it may cache the result. (2.0 style)
5013 'aclname' is the name of a defined ACL.
5015 NP: Using 'none' as the byte value here will override any quick_abort settings
5016 that may otherwise apply to the range request. The range request will
5017 be fully fetched from start to finish regardless of the client
5018 actions. This affects bandwidth usage.
5021 NAME: minimum_expiry_time
5024 LOC: Config.minimum_expiry_time
5027 The minimum caching time according to (Expires - Date)
5028 headers Squid honors if the object can't be revalidated.
5029 The default is 60 seconds.
5031 In reverse proxy environments it might be desirable to honor
5032 shorter object lifetimes. It is most likely better to make
5033 your server return a meaningful Last-Modified header however.
5035 In ESI environments where page fragments often have short
5036 lifetimes, this will often be best set to 0.
5039 NAME: store_avg_object_size
5043 LOC: Config.Store.avgObjectSize
5045 Average object size, used to estimate number of objects your
5046 cache can hold. The default is 13 KB.
5048 This is used to pre-seed the cache index memory allocation to
5049 reduce expensive reallocate operations while handling clients
5050 traffic. Too-large values may result in memory allocation during
5051 peak traffic, too-small values will result in wasted memory.
5053 Check the cache manager 'info' report metrics for the real
5054 object sizes seen by your Squid before tuning this.
5057 NAME: store_objects_per_bucket
5060 LOC: Config.Store.objectsPerBucket
5062 Target number of objects per bucket in the store hash table.
5063 Lowering this value increases the total number of buckets and
5064 also the storage maintenance rate. The default is 20.
5069 -----------------------------------------------------------------------------
5072 NAME: request_header_max_size
5076 LOC: Config.maxRequestHeaderSize
5078 This specifies the maximum size for HTTP headers in a request.
5079 Request headers are usually relatively small (about 512 bytes).
5080 Placing a limit on the request header size will catch certain
5081 bugs (for example with persistent connections) and possibly
5082 buffer-overflow or denial-of-service attacks.
5085 NAME: reply_header_max_size
5089 LOC: Config.maxReplyHeaderSize
5091 This specifies the maximum size for HTTP headers in a reply.
5092 Reply headers are usually relatively small (about 512 bytes).
5093 Placing a limit on the reply header size will catch certain
5094 bugs (for example with persistent connections) and possibly
5095 buffer-overflow or denial-of-service attacks.
5098 NAME: request_body_max_size
5102 DEFAULT_DOC: No limit.
5103 LOC: Config.maxRequestBodySize
5105 This specifies the maximum size for an HTTP request body.
5106 In other words, the maximum size of a PUT/POST request.
5107 A user who attempts to send a request with a body larger
5108 than this limit receives an "Invalid Request" error message.
5109 If you set this parameter to a zero (the default), there will
5110 be no limit imposed.
5112 See also client_request_buffer_max_size for an alternative
5113 limitation on client uploads which can be configured.
5116 NAME: client_request_buffer_max_size
5120 LOC: Config.maxRequestBufferSize
5122 This specifies the maximum buffer size of a client request.
5123 It prevents squid eating too much memory when somebody uploads
5127 NAME: chunked_request_body_max_size
5131 LOC: Config.maxChunkedRequestBodySize
5133 A broken or confused HTTP/1.1 client may send a chunked HTTP
5134 request to Squid. Squid does not have full support for that
5135 feature yet. To cope with such requests, Squid buffers the
5136 entire request and then dechunks request body to create a
5137 plain HTTP/1.0 request with a known content length. The plain
5138 request is then used by the rest of Squid code as usual.
5140 The option value specifies the maximum size of the buffer used
5141 to hold the request before the conversion. If the chunked
5142 request size exceeds the specified limit, the conversion
5143 fails, and the client receives an "unsupported request" error,
5144 as if dechunking was disabled.
5146 Dechunking is enabled by default. To disable conversion of
5147 chunked requests, set the maximum to zero.
5149 Request dechunking feature and this option in particular are a
5150 temporary hack. When chunking requests and responses are fully
5151 supported, there will be no need to buffer a chunked request.
5155 IFDEF: USE_HTTP_VIOLATIONS
5158 DEFAULT_DOC: Obey RFC 2616.
5159 LOC: Config.accessList.brokenPosts
5161 A list of ACL elements which, if matched, causes Squid to send
5162 an extra CRLF pair after the body of a PUT/POST request.
5164 Some HTTP servers has broken implementations of PUT/POST,
5165 and rely on an extra CRLF pair sent by some WWW clients.
5167 Quote from RFC2616 section 4.1 on this matter:
5169 Note: certain buggy HTTP/1.0 client implementations generate an
5170 extra CRLF's after a POST request. To restate what is explicitly
5171 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5172 a request with an extra CRLF.
5174 This clause only supports fast acl types.
5175 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5178 acl buggy_server url_regex ^http://....
5179 broken_posts allow buggy_server
5182 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5185 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5187 LOC: Adaptation::Config::use_indirect_client
5189 Controls whether the indirect client IP address (instead of the direct
5190 client IP address) is passed to adaptation services.
5192 See also: follow_x_forwarded_for adaptation_send_client_ip
5196 IFDEF: USE_HTTP_VIOLATIONS
5200 LOC: Config.onoff.via
5202 If set (default), Squid will include a Via header in requests and
5203 replies as required by RFC2616.
5209 LOC: Config.onoff.ie_refresh
5212 Microsoft Internet Explorer up until version 5.5 Service
5213 Pack 1 has an issue with transparent proxies, wherein it
5214 is impossible to force a refresh. Turning this on provides
5215 a partial fix to the problem, by causing all IMS-REFRESH
5216 requests from older IE versions to check the origin server
5217 for fresh content. This reduces hit ratio by some amount
5218 (~10% in my experience), but allows users to actually get
5219 fresh content when they want it. Note because Squid
5220 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5221 of 5.5 is unchanged from old versions of Squid (i.e. a
5222 forced refresh is impossible). Newer versions of IE will,
5223 hopefully, continue to have the new behavior and will be
5224 handled based on that assumption. This option defaults to
5225 the old Squid behavior, which is better for hit ratios but
5226 worse for clients using IE, if they need to be able to
5227 force fresh content.
5230 NAME: vary_ignore_expire
5233 LOC: Config.onoff.vary_ignore_expire
5236 Many HTTP servers supporting Vary gives such objects
5237 immediate expiry time with no cache-control header
5238 when requested by a HTTP/1.0 client. This option
5239 enables Squid to ignore such expiry times until
5240 HTTP/1.1 is fully implemented.
5242 WARNING: If turned on this may eventually cause some
5243 varying objects not intended for caching to get cached.
5246 NAME: request_entities
5248 LOC: Config.onoff.request_entities
5251 Squid defaults to deny GET and HEAD requests with request entities,
5252 as the meaning of such requests are undefined in the HTTP standard
5253 even if not explicitly forbidden.
5255 Set this directive to on if you have clients which insists
5256 on sending request entities in GET or HEAD requests. But be warned
5257 that there is server software (both proxies and web servers) which
5258 can fail to properly process this kind of request which may make you
5259 vulnerable to cache pollution attacks if enabled.
5262 NAME: request_header_access
5263 IFDEF: USE_HTTP_VIOLATIONS
5264 TYPE: http_header_access
5265 LOC: Config.request_header_access
5267 DEFAULT_DOC: No limits.
5269 Usage: request_header_access header_name allow|deny [!]aclname ...
5271 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5272 this feature could make you liable for problems which it
5275 This option replaces the old 'anonymize_headers' and the
5276 older 'http_anonymizer' option with something that is much
5277 more configurable. A list of ACLs for each header name allows
5278 removal of specific header fields under specific conditions.
5280 This option only applies to outgoing HTTP request headers (i.e.,
5281 headers sent by Squid to the next HTTP hop such as a cache peer
5282 or an origin server). The option has no effect during cache hit
5283 detection. The equivalent adaptation vectoring point in ICAP
5284 terminology is post-cache REQMOD.
5286 The option is applied to individual outgoing request header
5287 fields. For each request header field F, Squid uses the first
5288 qualifying sets of request_header_access rules:
5290 1. Rules with header_name equal to F's name.
5291 2. Rules with header_name 'Other', provided F's name is not
5292 on the hard-coded list of commonly used HTTP header names.
5293 3. Rules with header_name 'All'.
5295 Within that qualifying rule set, rule ACLs are checked as usual.
5296 If ACLs of an "allow" rule match, the header field is allowed to
5297 go through as is. If ACLs of a "deny" rule match, the header is
5298 removed and request_header_replace is then checked to identify
5299 if the removed header has a replacement. If no rules within the
5300 set have matching ACLs, the header field is left as is.
5302 For example, to achieve the same behavior as the old
5303 'http_anonymizer standard' option, you should use:
5305 request_header_access From deny all
5306 request_header_access Referer deny all
5307 request_header_access User-Agent deny all
5309 Or, to reproduce the old 'http_anonymizer paranoid' feature
5312 request_header_access Authorization allow all
5313 request_header_access Proxy-Authorization allow all
5314 request_header_access Cache-Control allow all
5315 request_header_access Content-Length allow all
5316 request_header_access Content-Type allow all
5317 request_header_access Date allow all
5318 request_header_access Host allow all
5319 request_header_access If-Modified-Since allow all
5320 request_header_access Pragma allow all
5321 request_header_access Accept allow all
5322 request_header_access Accept-Charset allow all
5323 request_header_access Accept-Encoding allow all
5324 request_header_access Accept-Language allow all
5325 request_header_access Connection allow all
5326 request_header_access All deny all
5328 HTTP reply headers are controlled with the reply_header_access directive.
5330 By default, all headers are allowed (no anonymizing is performed).
5333 NAME: reply_header_access
5334 IFDEF: USE_HTTP_VIOLATIONS
5335 TYPE: http_header_access
5336 LOC: Config.reply_header_access
5338 DEFAULT_DOC: No limits.
5340 Usage: reply_header_access header_name allow|deny [!]aclname ...
5342 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5343 this feature could make you liable for problems which it
5346 This option only applies to reply headers, i.e., from the
5347 server to the client.
5349 This is the same as request_header_access, but in the other
5350 direction. Please see request_header_access for detailed
5353 For example, to achieve the same behavior as the old
5354 'http_anonymizer standard' option, you should use:
5356 reply_header_access Server deny all
5357 reply_header_access WWW-Authenticate deny all
5358 reply_header_access Link deny all
5360 Or, to reproduce the old 'http_anonymizer paranoid' feature
5363 reply_header_access Allow allow all
5364 reply_header_access WWW-Authenticate allow all
5365 reply_header_access Proxy-Authenticate allow all
5366 reply_header_access Cache-Control allow all
5367 reply_header_access Content-Encoding allow all
5368 reply_header_access Content-Length allow all
5369 reply_header_access Content-Type allow all
5370 reply_header_access Date allow all
5371 reply_header_access Expires allow all
5372 reply_header_access Last-Modified allow all
5373 reply_header_access Location allow all
5374 reply_header_access Pragma allow all
5375 reply_header_access Content-Language allow all
5376 reply_header_access Retry-After allow all
5377 reply_header_access Title allow all
5378 reply_header_access Content-Disposition allow all
5379 reply_header_access Connection allow all
5380 reply_header_access All deny all
5382 HTTP request headers are controlled with the request_header_access directive.
5384 By default, all headers are allowed (no anonymizing is
5388 NAME: request_header_replace header_replace
5389 IFDEF: USE_HTTP_VIOLATIONS
5390 TYPE: http_header_replace
5391 LOC: Config.request_header_access
5394 Usage: request_header_replace header_name message
5395 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
5397 This option allows you to change the contents of headers
5398 denied with request_header_access above, by replacing them
5399 with some fixed string.
5401 This only applies to request headers, not reply headers.
5403 By default, headers are removed if denied.
5406 NAME: reply_header_replace
5407 IFDEF: USE_HTTP_VIOLATIONS
5408 TYPE: http_header_replace
5409 LOC: Config.reply_header_access
5412 Usage: reply_header_replace header_name message
5413 Example: reply_header_replace Server Foo/1.0
5415 This option allows you to change the contents of headers
5416 denied with reply_header_access above, by replacing them
5417 with some fixed string.
5419 This only applies to reply headers, not request headers.
5421 By default, headers are removed if denied.
5424 NAME: request_header_add
5425 TYPE: HeaderWithAclList
5426 LOC: Config.request_header_add
5429 Usage: request_header_add field-name field-value acl1 [acl2] ...
5430 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
5432 This option adds header fields to outgoing HTTP requests (i.e.,
5433 request headers sent by Squid to the next HTTP hop such as a
5434 cache peer or an origin server). The option has no effect during
5435 cache hit detection. The equivalent adaptation vectoring point
5436 in ICAP terminology is post-cache REQMOD.
5438 Field-name is a token specifying an HTTP header name. If a
5439 standard HTTP header name is used, Squid does not check whether
5440 the new header conflicts with any existing headers or violates
5441 HTTP rules. If the request to be modified already contains a
5442 field with the same name, the old field is preserved but the
5443 header field values are not merged.
5445 Field-value is either a token or a quoted string. If quoted
5446 string format is used, then the surrounding quotes are removed
5447 while escape sequences and %macros are processed.
5449 In theory, all of the logformat codes can be used as %macros.
5450 However, unlike logging (which happens at the very end of
5451 transaction lifetime), the transaction may not yet have enough
5452 information to expand a macro when the new header value is needed.
5453 And some information may already be available to Squid but not yet
5454 committed where the macro expansion code can access it (report
5455 such instances!). The macro will be expanded into a single dash
5456 ('-') in such cases. Not all macros have been tested.
5458 One or more Squid ACLs may be specified to restrict header
5459 injection to matching requests. As always in squid.conf, all
5460 ACLs in an option ACL list must be satisfied for the insertion
5461 to happen. The request_header_add option supports fast ACLs
5470 This option used to log custom information about the master
5471 transaction. For example, an admin may configure Squid to log
5472 which "user group" the transaction belongs to, where "user group"
5473 will be determined based on a set of ACLs and not [just]
5474 authentication information.
5475 Values of key/value pairs can be logged using %{key}note macros:
5477 note key value acl ...
5478 logformat myFormat ... %{key}note ...
5481 NAME: relaxed_header_parser
5482 COMMENT: on|off|warn
5484 LOC: Config.onoff.relaxed_header_parser
5487 In the default "on" setting Squid accepts certain forms
5488 of non-compliant HTTP messages where it is unambiguous
5489 what the sending application intended even if the message
5490 is not correctly formatted. The messages is then normalized
5491 to the correct form when forwarded by Squid.
5493 If set to "warn" then a warning will be emitted in cache.log
5494 each time such HTTP error is encountered.
5496 If set to "off" then such HTTP errors will cause the request
5497 or response to be rejected.
5502 -----------------------------------------------------------------------------
5505 NAME: forward_timeout
5508 LOC: Config.Timeout.forward
5511 This parameter specifies how long Squid should at most attempt in
5512 finding a forwarding path for the request before giving up.
5515 NAME: connect_timeout
5518 LOC: Config.Timeout.connect
5521 This parameter specifies how long to wait for the TCP connect to
5522 the requested server or peer to complete before Squid should
5523 attempt to find another path where to forward the request.
5526 NAME: peer_connect_timeout
5529 LOC: Config.Timeout.peer_connect
5532 This parameter specifies how long to wait for a pending TCP
5533 connection to a peer cache. The default is 30 seconds. You
5534 may also set different timeout values for individual neighbors
5535 with the 'connect-timeout' option on a 'cache_peer' line.
5541 LOC: Config.Timeout.read
5544 The read_timeout is applied on server-side connections. After
5545 each successful read(), the timeout will be extended by this
5546 amount. If no data is read again after this amount of time,
5547 the request is aborted and logged with ERR_READ_TIMEOUT. The
5548 default is 15 minutes.
5554 LOC: Config.Timeout.write
5557 This timeout is tracked for all connections that have data
5558 available for writing and are waiting for the socket to become
5559 ready. After each successful write, the timeout is extended by
5560 the configured amount. If Squid has data to write but the
5561 connection is not ready for the configured duration, the
5562 transaction associated with the connection is terminated. The
5563 default is 15 minutes.
5566 NAME: request_timeout
5568 LOC: Config.Timeout.request
5571 How long to wait for complete HTTP request headers after initial
5572 connection establishment.
5575 NAME: client_idle_pconn_timeout persistent_request_timeout
5577 LOC: Config.Timeout.clientIdlePconn
5580 How long to wait for the next HTTP request on a persistent
5581 client connection after the previous request completes.
5584 NAME: client_lifetime
5587 LOC: Config.Timeout.lifetime
5590 The maximum amount of time a client (browser) is allowed to
5591 remain connected to the cache process. This protects the Cache
5592 from having a lot of sockets (and hence file descriptors) tied up
5593 in a CLOSE_WAIT state from remote clients that go away without
5594 properly shutting down (either because of a network failure or
5595 because of a poor client implementation). The default is one
5598 NOTE: The default value is intended to be much larger than any
5599 client would ever need to be connected to your cache. You
5600 should probably change client_lifetime only as a last resort.
5601 If you seem to have many client connections tying up
5602 filedescriptors, we recommend first tuning the read_timeout,
5603 request_timeout, persistent_request_timeout and quick_abort values.
5606 NAME: half_closed_clients
5608 LOC: Config.onoff.half_closed_clients
5611 Some clients may shutdown the sending side of their TCP
5612 connections, while leaving their receiving sides open. Sometimes,
5613 Squid can not tell the difference between a half-closed and a
5614 fully-closed TCP connection.
5616 By default, Squid will immediately close client connections when
5617 read(2) returns "no more data to read."
5619 Change this option to 'on' and Squid will keep open connections
5620 until a read(2) or write(2) on the socket returns an error.
5621 This may show some benefits for reverse proxies. But if not
5622 it is recommended to leave OFF.
5625 NAME: server_idle_pconn_timeout pconn_timeout
5627 LOC: Config.Timeout.serverIdlePconn
5630 Timeout for idle persistent connections to servers and other
5637 LOC: Ident::TheConfig.timeout
5640 Maximum time to wait for IDENT lookups to complete.
5642 If this is too high, and you enabled IDENT lookups from untrusted
5643 users, you might be susceptible to denial-of-service by having
5644 many ident requests going at once.
5647 NAME: shutdown_lifetime
5650 LOC: Config.shutdownLifetime
5653 When SIGTERM or SIGHUP is received, the cache is put into
5654 "shutdown pending" mode until all active sockets are closed.
5655 This value is the lifetime to set for all open descriptors
5656 during shutdown mode. Any active clients after this many
5657 seconds will receive a 'timeout' message.
5661 ADMINISTRATIVE PARAMETERS
5662 -----------------------------------------------------------------------------
5668 LOC: Config.adminEmail
5670 Email-address of local cache manager who will receive
5671 mail if the cache dies. The default is "webmaster".
5677 LOC: Config.EmailFrom
5679 From: email-address for mail sent when the cache dies.
5680 The default is to use 'squid@unique_hostname'.
5682 See also: unique_hostname directive.
5688 LOC: Config.EmailProgram
5690 Email program used to send mail if the cache dies.
5691 The default is "mail". The specified program must comply
5692 with the standard Unix mail syntax:
5693 mail-program recipient < mailfile
5695 Optional command line options can be specified.
5698 NAME: cache_effective_user
5700 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
5701 LOC: Config.effectiveUser
5703 If you start Squid as root, it will change its effective/real
5704 UID/GID to the user specified below. The default is to change
5705 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
5706 see also; cache_effective_group
5709 NAME: cache_effective_group
5712 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
5713 LOC: Config.effectiveGroup
5715 Squid sets the GID to the effective user's default group ID
5716 (taken from the password file) and supplementary group list
5717 from the groups membership.
5719 If you want Squid to run with a specific GID regardless of
5720 the group memberships of the effective user then set this
5721 to the group (or GID) you want Squid to run as. When set
5722 all other group privileges of the effective user are ignored
5723 and only this GID is effective. If Squid is not started as
5724 root the user starting Squid MUST be member of the specified
5727 This option is not recommended by the Squid Team.
5728 Our preference is for administrators to configure a secure
5729 user account for squid with UID/GID matching system policies.
5732 NAME: httpd_suppress_version_string
5736 LOC: Config.onoff.httpd_suppress_version_string
5738 Suppress Squid version string info in HTTP headers and HTML error pages.
5741 NAME: visible_hostname
5743 LOC: Config.visibleHostname
5745 DEFAULT_DOC: Automatically detect the system host name
5747 If you want to present a special hostname in error messages, etc,
5748 define this. Otherwise, the return value of gethostname()
5749 will be used. If you have multiple caches in a cluster and
5750 get errors about IP-forwarding you must set them to have individual
5751 names with this setting.
5754 NAME: unique_hostname
5756 LOC: Config.uniqueHostname
5758 DEFAULT_DOC: Copy the value from visible_hostname
5760 If you want to have multiple machines with the same
5761 'visible_hostname' you must give each machine a different
5762 'unique_hostname' so forwarding loops can be detected.
5765 NAME: hostname_aliases
5767 LOC: Config.hostnameAliases
5770 A list of other DNS names your cache has.
5778 Minimum umask which should be enforced while the proxy
5779 is running, in addition to the umask set at startup.
5781 For a traditional octal representation of umasks, start
5786 OPTIONS FOR THE CACHE REGISTRATION SERVICE
5787 -----------------------------------------------------------------------------
5789 This section contains parameters for the (optional) cache
5790 announcement service. This service is provided to help
5791 cache administrators locate one another in order to join or
5792 create cache hierarchies.
5794 An 'announcement' message is sent (via UDP) to the registration
5795 service by Squid. By default, the announcement message is NOT
5796 SENT unless you enable it with 'announce_period' below.
5798 The announcement message includes your hostname, plus the
5799 following information from this configuration file:
5805 All current information is processed regularly and made
5806 available on the Web at http://www.ircache.net/Cache/Tracker/.
5809 NAME: announce_period
5811 LOC: Config.Announce.period
5813 DEFAULT_DOC: Announcement messages disabled.
5815 This is how frequently to send cache announcements.
5817 To enable announcing your cache, just set an announce period.
5820 announce_period 1 day
5825 DEFAULT: tracker.ircache.net
5826 LOC: Config.Announce.host
5828 Set the hostname where announce registration messages will be sent.
5830 See also announce_port and announce_file
5836 LOC: Config.Announce.file
5838 The contents of this file will be included in the announce
5839 registration messages.
5845 LOC: Config.Announce.port
5847 Set the port where announce registration messages will be sent.
5849 See also announce_host and announce_file
5853 HTTPD-ACCELERATOR OPTIONS
5854 -----------------------------------------------------------------------------
5857 NAME: httpd_accel_surrogate_id
5860 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
5861 LOC: Config.Accel.surrogate_id
5863 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
5864 need an identification token to allow control targeting. Because
5865 a farm of surrogates may all perform the same tasks, they may share
5866 an identification token.
5869 NAME: http_accel_surrogate_remote
5873 LOC: Config.onoff.surrogate_is_remote
5875 Remote surrogates (such as those in a CDN) honour the header
5876 "Surrogate-Control: no-store-remote".
5878 Set this to on to have squid behave as a remote surrogate.
5882 IFDEF: USE_SQUID_ESI
5883 COMMENT: libxml2|expat|custom
5885 LOC: ESIParser::Type
5888 ESI markup is not strictly XML compatible. The custom ESI parser
5889 will give higher performance, but cannot handle non ASCII character
5894 DELAY POOL PARAMETERS
5895 -----------------------------------------------------------------------------
5899 TYPE: delay_pool_count
5901 IFDEF: USE_DELAY_POOLS
5904 This represents the number of delay pools to be used. For example,
5905 if you have one class 2 delay pool and one class 3 delays pool, you
5906 have a total of 2 delay pools.
5908 See also delay_parameters, delay_class, delay_access for pool
5909 configuration details.
5913 TYPE: delay_pool_class
5915 IFDEF: USE_DELAY_POOLS
5918 This defines the class of each delay pool. There must be exactly one
5919 delay_class line for each delay pool. For example, to define two
5920 delay pools, one of class 2 and one of class 3, the settings above
5924 delay_pools 4 # 4 delay pools
5925 delay_class 1 2 # pool 1 is a class 2 pool
5926 delay_class 2 3 # pool 2 is a class 3 pool
5927 delay_class 3 4 # pool 3 is a class 4 pool
5928 delay_class 4 5 # pool 4 is a class 5 pool
5930 The delay pool classes are:
5932 class 1 Everything is limited by a single aggregate
5935 class 2 Everything is limited by a single aggregate
5936 bucket as well as an "individual" bucket chosen
5937 from bits 25 through 32 of the IPv4 address.
5939 class 3 Everything is limited by a single aggregate
5940 bucket as well as a "network" bucket chosen
5941 from bits 17 through 24 of the IP address and a
5942 "individual" bucket chosen from bits 17 through
5943 32 of the IPv4 address.
5945 class 4 Everything in a class 3 delay pool, with an
5946 additional limit on a per user basis. This
5947 only takes effect if the username is established
5948 in advance - by forcing authentication in your
5951 class 5 Requests are grouped according their tag (see
5952 external_acl's tag= reply).
5955 Each pool also requires a delay_parameters directive to configure the pool size
5956 and speed limits used whenever the pool is applied to a request. Along with
5957 a set of delay_access directives to determine when it is used.
5959 NOTE: If an IP address is a.b.c.d
5960 -> bits 25 through 32 are "d"
5961 -> bits 17 through 24 are "c"
5962 -> bits 17 through 32 are "c * 256 + d"
5964 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
5965 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
5967 This clause only supports fast acl types.
5968 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5970 See also delay_parameters and delay_access.
5974 TYPE: delay_pool_access
5976 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
5977 IFDEF: USE_DELAY_POOLS
5980 This is used to determine which delay pool a request falls into.
5982 delay_access is sorted per pool and the matching starts with pool 1,
5983 then pool 2, ..., and finally pool N. The first delay pool where the
5984 request is allowed is selected for the request. If it does not allow
5985 the request to any pool then the request is not delayed (default).
5987 For example, if you want some_big_clients in delay
5988 pool 1 and lotsa_little_clients in delay pool 2:
5990 delay_access 1 allow some_big_clients
5991 delay_access 1 deny all
5992 delay_access 2 allow lotsa_little_clients
5993 delay_access 2 deny all
5994 delay_access 3 allow authenticated_clients
5996 See also delay_parameters and delay_class.
6000 NAME: delay_parameters
6001 TYPE: delay_pool_rates
6003 IFDEF: USE_DELAY_POOLS
6006 This defines the parameters for a delay pool. Each delay pool has
6007 a number of "buckets" associated with it, as explained in the
6008 description of delay_class.
6010 For a class 1 delay pool, the syntax is:
6012 delay_parameters pool aggregate
6014 For a class 2 delay pool:
6016 delay_parameters pool aggregate individual
6018 For a class 3 delay pool:
6020 delay_parameters pool aggregate network individual
6022 For a class 4 delay pool:
6024 delay_parameters pool aggregate network individual user
6026 For a class 5 delay pool:
6028 delay_parameters pool tagrate
6030 The option variables are:
6032 pool a pool number - ie, a number between 1 and the
6033 number specified in delay_pools as used in
6036 aggregate the speed limit parameters for the aggregate bucket
6039 individual the speed limit parameters for the individual
6040 buckets (class 2, 3).
6042 network the speed limit parameters for the network buckets
6045 user the speed limit parameters for the user buckets
6048 tagrate the speed limit parameters for the tag buckets
6051 A pair of delay parameters is written restore/maximum, where restore is
6052 the number of bytes (not bits - modem and network speeds are usually
6053 quoted in bits) per second placed into the bucket, and maximum is the
6054 maximum number of bytes which can be in the bucket at any time.
6056 There must be one delay_parameters line for each delay pool.
6059 For example, if delay pool number 1 is a class 2 delay pool as in the
6060 above example, and is being used to strictly limit each host to 64Kbit/sec
6061 (plus overheads), with no overall limit, the line is:
6063 delay_parameters 1 -1/-1 8000/8000
6065 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
6067 Note that the figure -1 is used to represent "unlimited".
6070 And, if delay pool number 2 is a class 3 delay pool as in the above
6071 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6072 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6073 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6074 to permit a decent web page to be downloaded at a decent speed
6075 (if the network is not being limited due to overuse) but slow down
6076 large downloads more significantly:
6078 delay_parameters 2 32000/32000 8000/8000 600/8000
6080 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
6081 8 x 8000 KByte/sec -> 64Kbit/sec.
6082 8 x 600 Byte/sec -> 4800bit/sec.
6085 Finally, for a class 4 delay pool as in the example - each user will
6086 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6088 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6091 See also delay_class and delay_access.
6095 NAME: delay_initial_bucket_level
6096 COMMENT: (percent, 0-100)
6099 IFDEF: USE_DELAY_POOLS
6100 LOC: Config.Delay.initial
6102 The initial bucket percentage is used to determine how much is put
6103 in each bucket when squid starts, is reconfigured, or first notices
6104 a host accessing it (in class 2 and class 3, individual hosts and
6105 networks only have buckets associated with them once they have been
6110 CLIENT DELAY POOL PARAMETERS
6111 -----------------------------------------------------------------------------
6114 NAME: client_delay_pools
6115 TYPE: client_delay_pool_count
6117 IFDEF: USE_DELAY_POOLS
6118 LOC: Config.ClientDelay
6120 This option specifies the number of client delay pools used. It must
6121 preceed other client_delay_* options.
6124 client_delay_pools 2
6126 See also client_delay_parameters and client_delay_access.
6129 NAME: client_delay_initial_bucket_level
6130 COMMENT: (percent, 0-no_limit)
6133 IFDEF: USE_DELAY_POOLS
6134 LOC: Config.ClientDelay.initial
6136 This option determines the initial bucket size as a percentage of
6137 max_bucket_size from client_delay_parameters. Buckets are created
6138 at the time of the "first" connection from the matching IP. Idle
6139 buckets are periodically deleted up.
6141 You can specify more than 100 percent but note that such "oversized"
6142 buckets are not refilled until their size goes down to max_bucket_size
6143 from client_delay_parameters.
6146 client_delay_initial_bucket_level 50
6149 NAME: client_delay_parameters
6150 TYPE: client_delay_pool_rates
6152 IFDEF: USE_DELAY_POOLS
6153 LOC: Config.ClientDelay
6156 This option configures client-side bandwidth limits using the
6159 client_delay_parameters pool speed_limit max_bucket_size
6161 pool is an integer ID used for client_delay_access matching.
6163 speed_limit is bytes added to the bucket per second.
6165 max_bucket_size is the maximum size of a bucket, enforced after any
6166 speed_limit additions.
6168 Please see the delay_parameters option for more information and
6172 client_delay_parameters 1 1024 2048
6173 client_delay_parameters 2 51200 16384
6175 See also client_delay_access.
6179 NAME: client_delay_access
6180 TYPE: client_delay_pool_access
6182 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6183 IFDEF: USE_DELAY_POOLS
6184 LOC: Config.ClientDelay
6186 This option determines the client-side delay pool for the
6189 client_delay_access pool_ID allow|deny acl_name
6191 All client_delay_access options are checked in their pool ID
6192 order, starting with pool 1. The first checked pool with allowed
6193 request is selected for the request. If no ACL matches or there
6194 are no client_delay_access options, the request bandwidth is not
6197 The ACL-selected pool is then used to find the
6198 client_delay_parameters for the request. Client-side pools are
6199 not used to aggregate clients. Clients are always aggregated
6200 based on their source IP addresses (one bucket per source IP).
6202 This clause only supports fast acl types.
6203 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6204 Additionally, only the client TCP connection details are available.
6205 ACLs testing HTTP properties will not work.
6207 Please see delay_access for more examples.
6210 client_delay_access 1 allow low_rate_network
6211 client_delay_access 2 allow vips_network
6214 See also client_delay_parameters and client_delay_pools.
6218 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6219 -----------------------------------------------------------------------------
6224 LOC: Config.Wccp.router
6226 DEFAULT_DOC: WCCP disabled.
6229 Use this option to define your WCCP ``home'' router for
6232 wccp_router supports a single WCCP(v1) router
6234 wccp2_router supports multiple WCCPv2 routers
6236 only one of the two may be used at the same time and defines
6237 which version of WCCP to use.
6241 TYPE: IpAddress_list
6242 LOC: Config.Wccp2.router
6244 DEFAULT_DOC: WCCPv2 disabled.
6247 Use this option to define your WCCP ``home'' router for
6250 wccp_router supports a single WCCP(v1) router
6252 wccp2_router supports multiple WCCPv2 routers
6254 only one of the two may be used at the same time and defines
6255 which version of WCCP to use.
6260 LOC: Config.Wccp.version
6264 This directive is only relevant if you need to set up WCCP(v1)
6265 to some very old and end-of-life Cisco routers. In all other
6266 setups it must be left unset or at the default setting.
6267 It defines an internal version in the WCCP(v1) protocol,
6268 with version 4 being the officially documented protocol.
6270 According to some users, Cisco IOS 11.2 and earlier only
6271 support WCCP version 3. If you're using that or an earlier
6272 version of IOS, you may need to change this value to 3, otherwise
6273 do not specify this parameter.
6276 NAME: wccp2_rebuild_wait
6278 LOC: Config.Wccp2.rebuildwait
6282 If this is enabled Squid will wait for the cache dir rebuild to finish
6283 before sending the first wccp2 HereIAm packet
6286 NAME: wccp2_forwarding_method
6288 LOC: Config.Wccp2.forwarding_method
6292 WCCP2 allows the setting of forwarding methods between the
6293 router/switch and the cache. Valid values are as follows:
6295 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6296 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6298 Currently (as of IOS 12.4) cisco routers only support GRE.
6299 Cisco switches only support the L2 redirect assignment method.
6302 NAME: wccp2_return_method
6304 LOC: Config.Wccp2.return_method
6308 WCCP2 allows the setting of return methods between the
6309 router/switch and the cache for packets that the cache
6310 decides not to handle. Valid values are as follows:
6312 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6313 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6315 Currently (as of IOS 12.4) cisco routers only support GRE.
6316 Cisco switches only support the L2 redirect assignment.
6318 If the "ip wccp redirect exclude in" command has been
6319 enabled on the cache interface, then it is still safe for
6320 the proxy server to use a l2 redirect method even if this
6321 option is set to GRE.
6324 NAME: wccp2_assignment_method
6326 LOC: Config.Wccp2.assignment_method
6330 WCCP2 allows the setting of methods to assign the WCCP hash
6331 Valid values are as follows:
6333 hash - Hash assignment
6334 mask - Mask assignment
6336 As a general rule, cisco routers support the hash assignment method
6337 and cisco switches support the mask assignment method.
6342 LOC: Config.Wccp2.info
6343 DEFAULT_IF_NONE: standard 0
6344 DEFAULT_DOC: Use the 'web-cache' standard service.
6347 WCCP2 allows for multiple traffic services. There are two
6348 types: "standard" and "dynamic". The standard type defines
6349 one service id - http (id 0). The dynamic service ids can be from
6350 51 to 255 inclusive. In order to use a dynamic service id
6351 one must define the type of traffic to be redirected; this is done
6352 using the wccp2_service_info option.
6354 The "standard" type does not require a wccp2_service_info option,
6355 just specifying the service id will suffice.
6357 MD5 service authentication can be enabled by adding
6358 "password=<password>" to the end of this service declaration.
6362 wccp2_service standard 0 # for the 'web-cache' standard service
6363 wccp2_service dynamic 80 # a dynamic service type which will be
6364 # fleshed out with subsequent options.
6365 wccp2_service standard 0 password=foo
6368 NAME: wccp2_service_info
6369 TYPE: wccp2_service_info
6370 LOC: Config.Wccp2.info
6374 Dynamic WCCPv2 services require further information to define the
6375 traffic you wish to have diverted.
6379 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
6380 priority=<priority> ports=<port>,<port>..
6382 The relevant WCCPv2 flags:
6383 + src_ip_hash, dst_ip_hash
6384 + source_port_hash, dst_port_hash
6385 + src_ip_alt_hash, dst_ip_alt_hash
6386 + src_port_alt_hash, dst_port_alt_hash
6389 The port list can be one to eight entries.
6393 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
6394 priority=240 ports=80
6396 Note: the service id must have been defined by a previous
6397 'wccp2_service dynamic <id>' entry.
6402 LOC: Config.Wccp2.weight
6406 Each cache server gets assigned a set of the destination
6407 hash proportional to their weight.
6412 LOC: Config.Wccp.address
6414 DEFAULT_DOC: Address selected by the operating system.
6417 Use this option if you require WCCPv2 to use a specific
6420 The default behavior is to not bind to any specific address.
6425 LOC: Config.Wccp2.address
6427 DEFAULT_DOC: Address selected by the operating system.
6430 Use this option if you require WCCP to use a specific
6433 The default behavior is to not bind to any specific address.
6437 PERSISTENT CONNECTION HANDLING
6438 -----------------------------------------------------------------------------
6440 Also see "pconn_timeout" in the TIMEOUTS section
6443 NAME: client_persistent_connections
6445 LOC: Config.onoff.client_pconns
6448 Persistent connection support for clients.
6449 Squid uses persistent connections (when allowed). You can use
6450 this option to disable persistent connections with clients.
6453 NAME: server_persistent_connections
6455 LOC: Config.onoff.server_pconns
6458 Persistent connection support for servers.
6459 Squid uses persistent connections (when allowed). You can use
6460 this option to disable persistent connections with servers.
6463 NAME: persistent_connection_after_error
6465 LOC: Config.onoff.error_pconns
6468 With this directive the use of persistent connections after
6469 HTTP errors can be disabled. Useful if you have clients
6470 who fail to handle errors on persistent connections proper.
6473 NAME: detect_broken_pconn
6475 LOC: Config.onoff.detect_broken_server_pconns
6478 Some servers have been found to incorrectly signal the use
6479 of HTTP/1.0 persistent connections even on replies not
6480 compatible, causing significant delays. This server problem
6481 has mostly been seen on redirects.
6483 By enabling this directive Squid attempts to detect such
6484 broken replies and automatically assume the reply is finished
6485 after 10 seconds timeout.
6489 CACHE DIGEST OPTIONS
6490 -----------------------------------------------------------------------------
6493 NAME: digest_generation
6494 IFDEF: USE_CACHE_DIGESTS
6496 LOC: Config.onoff.digest_generation
6499 This controls whether the server will generate a Cache Digest
6500 of its contents. By default, Cache Digest generation is
6501 enabled if Squid is compiled with --enable-cache-digests defined.
6504 NAME: digest_bits_per_entry
6505 IFDEF: USE_CACHE_DIGESTS
6507 LOC: Config.digest.bits_per_entry
6510 This is the number of bits of the server's Cache Digest which
6511 will be associated with the Digest entry for a given HTTP
6512 Method and URL (public key) combination. The default is 5.
6515 NAME: digest_rebuild_period
6516 IFDEF: USE_CACHE_DIGESTS
6519 LOC: Config.digest.rebuild_period
6522 This is the wait time between Cache Digest rebuilds.
6525 NAME: digest_rewrite_period
6527 IFDEF: USE_CACHE_DIGESTS
6529 LOC: Config.digest.rewrite_period
6532 This is the wait time between Cache Digest writes to
6536 NAME: digest_swapout_chunk_size
6539 IFDEF: USE_CACHE_DIGESTS
6540 LOC: Config.digest.swapout_chunk_size
6543 This is the number of bytes of the Cache Digest to write to
6544 disk at a time. It defaults to 4096 bytes (4KB), the Squid
6548 NAME: digest_rebuild_chunk_percentage
6549 COMMENT: (percent, 0-100)
6550 IFDEF: USE_CACHE_DIGESTS
6552 LOC: Config.digest.rebuild_chunk_percentage
6555 This is the percentage of the Cache Digest to be scanned at a
6556 time. By default it is set to 10% of the Cache Digest.
6561 -----------------------------------------------------------------------------
6566 LOC: Config.Port.snmp
6568 DEFAULT_DOC: SNMP disabled.
6571 The port number where Squid listens for SNMP requests. To enable
6572 SNMP support set this to a suitable port number. Port number
6573 3401 is often used for the Squid SNMP agent. By default it's
6574 set to "0" (disabled)
6582 LOC: Config.accessList.snmp
6584 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
6587 Allowing or denying access to the SNMP port.
6589 All access to the agent is denied by default.
6592 snmp_access allow|deny [!]aclname ...
6594 This clause only supports fast acl types.
6595 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6598 snmp_access allow snmppublic localhost
6599 snmp_access deny all
6602 NAME: snmp_incoming_address
6604 LOC: Config.Addrs.snmp_incoming
6606 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
6609 Just like 'udp_incoming_address', but for the SNMP port.
6611 snmp_incoming_address is used for the SNMP socket receiving
6612 messages from SNMP agents.
6614 The default snmp_incoming_address is to listen on all
6615 available network interfaces.
6618 NAME: snmp_outgoing_address
6620 LOC: Config.Addrs.snmp_outgoing
6622 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
6625 Just like 'udp_outgoing_address', but for the SNMP port.
6627 snmp_outgoing_address is used for SNMP packets returned to SNMP
6630 If snmp_outgoing_address is not set it will use the same socket
6631 as snmp_incoming_address. Only change this if you want to have
6632 SNMP replies sent using another address than where this Squid
6633 listens for SNMP queries.
6635 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
6636 the same value since they both use the same port.
6641 -----------------------------------------------------------------------------
6644 NAME: icp_port udp_port
6647 DEFAULT_DOC: ICP disabled.
6648 LOC: Config.Port.icp
6650 The port number where Squid sends and receives ICP queries to
6651 and from neighbor caches. The standard UDP port for ICP is 3130.
6654 icp_port @DEFAULT_ICP_PORT@
6661 DEFAULT_DOC: HTCP disabled.
6662 LOC: Config.Port.htcp
6664 The port number where Squid sends and receives HTCP queries to
6665 and from neighbor caches. To turn it on you want to set it to
6672 NAME: log_icp_queries
6676 LOC: Config.onoff.log_udp
6678 If set, ICP queries are logged to access.log. You may wish
6679 do disable this if your ICP load is VERY high to speed things
6680 up or to simplify log analysis.
6683 NAME: udp_incoming_address
6685 LOC:Config.Addrs.udp_incoming
6687 DEFAULT_DOC: Accept packets from all machine interfaces.
6689 udp_incoming_address is used for UDP packets received from other
6692 The default behavior is to not bind to any specific address.
6694 Only change this if you want to have all UDP queries received on
6695 a specific interface/address.
6697 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
6698 modules. Altering it will affect all of them in the same manner.
6700 see also; udp_outgoing_address
6702 NOTE, udp_incoming_address and udp_outgoing_address can not
6703 have the same value since they both use the same port.
6706 NAME: udp_outgoing_address
6708 LOC: Config.Addrs.udp_outgoing
6710 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
6712 udp_outgoing_address is used for UDP packets sent out to other
6715 The default behavior is to not bind to any specific address.
6717 Instead it will use the same socket as udp_incoming_address.
6718 Only change this if you want to have UDP queries sent using another
6719 address than where this Squid listens for UDP queries from other
6722 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
6723 modules. Altering it will affect all of them in the same manner.
6725 see also; udp_incoming_address
6727 NOTE, udp_incoming_address and udp_outgoing_address can not
6728 have the same value since they both use the same port.
6735 LOC: Config.onoff.icp_hit_stale
6737 If you want to return ICP_HIT for stale cache objects, set this
6738 option to 'on'. If you have sibling relationships with caches
6739 in other administrative domains, this should be 'off'. If you only
6740 have sibling relationships with caches under your control,
6741 it is probably okay to set this to 'on'.
6742 If set to 'on', your siblings should use the option "allow-miss"
6743 on their cache_peer lines for connecting to you.
6746 NAME: minimum_direct_hops
6749 LOC: Config.minDirectHops
6751 If using the ICMP pinging stuff, do direct fetches for sites
6752 which are no more than this many hops away.
6755 NAME: minimum_direct_rtt
6759 LOC: Config.minDirectRtt
6761 If using the ICMP pinging stuff, do direct fetches for sites
6762 which are no more than this many rtt milliseconds away.
6768 LOC: Config.Netdb.low
6770 The low water mark for the ICMP measurement database.
6772 Note: high watermark controlled by netdb_high directive.
6774 These watermarks are counts, not percents. The defaults are
6775 (low) 900 and (high) 1000. When the high water mark is
6776 reached, database entries will be deleted until the low
6783 LOC: Config.Netdb.high
6785 The high water mark for the ICMP measurement database.
6787 Note: low watermark controlled by netdb_low directive.
6789 These watermarks are counts, not percents. The defaults are
6790 (low) 900 and (high) 1000. When the high water mark is
6791 reached, database entries will be deleted until the low
6795 NAME: netdb_ping_period
6797 LOC: Config.Netdb.period
6800 The minimum period for measuring a site. There will be at
6801 least this much delay between successive pings to the same
6802 network. The default is five minutes.
6809 LOC: Config.onoff.query_icmp
6811 If you want to ask your peers to include ICMP data in their ICP
6812 replies, enable this option.
6814 If your peer has configured Squid (during compilation) with
6815 '--enable-icmp' that peer will send ICMP pings to origin server
6816 sites of the URLs it receives. If you enable this option the
6817 ICP replies from that peer will include the ICMP data (if available).
6818 Then, when choosing a parent cache, Squid will choose the parent with
6819 the minimal RTT to the origin server. When this happens, the
6820 hierarchy field of the access.log will be
6821 "CLOSEST_PARENT_MISS". This option is off by default.
6824 NAME: test_reachability
6828 LOC: Config.onoff.test_reachability
6830 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
6831 instead of ICP_MISS if the target host is NOT in the ICMP
6832 database, or has a zero RTT.
6835 NAME: icp_query_timeout
6838 DEFAULT_DOC: Dynamic detection.
6840 LOC: Config.Timeout.icp_query
6842 Normally Squid will automatically determine an optimal ICP
6843 query timeout value based on the round-trip-time of recent ICP
6844 queries. If you want to override the value determined by
6845 Squid, set this 'icp_query_timeout' to a non-zero value. This
6846 value is specified in MILLISECONDS, so, to use a 2-second
6847 timeout (the old default), you would write:
6849 icp_query_timeout 2000
6852 NAME: maximum_icp_query_timeout
6856 LOC: Config.Timeout.icp_query_max
6858 Normally the ICP query timeout is determined dynamically. But
6859 sometimes it can lead to very large values (say 5 seconds).
6860 Use this option to put an upper limit on the dynamic timeout
6861 value. Do NOT use this option to always use a fixed (instead
6862 of a dynamic) timeout value. To set a fixed timeout see the
6863 'icp_query_timeout' directive.
6866 NAME: minimum_icp_query_timeout
6870 LOC: Config.Timeout.icp_query_min
6872 Normally the ICP query timeout is determined dynamically. But
6873 sometimes it can lead to very small timeouts, even lower than
6874 the normal latency variance on your link due to traffic.
6875 Use this option to put an lower limit on the dynamic timeout
6876 value. Do NOT use this option to always use a fixed (instead
6877 of a dynamic) timeout value. To set a fixed timeout see the
6878 'icp_query_timeout' directive.
6881 NAME: background_ping_rate
6885 LOC: Config.backgroundPingRate
6887 Controls how often the ICP pings are sent to siblings that
6888 have background-ping set.
6892 MULTICAST ICP OPTIONS
6893 -----------------------------------------------------------------------------
6898 LOC: Config.mcast_group_list
6901 This tag specifies a list of multicast groups which your server
6902 should join to receive multicasted ICP queries.
6904 NOTE! Be very careful what you put here! Be sure you
6905 understand the difference between an ICP _query_ and an ICP
6906 _reply_. This option is to be set only if you want to RECEIVE
6907 multicast queries. Do NOT set this option to SEND multicast
6908 ICP (use cache_peer for that). ICP replies are always sent via
6909 unicast, so this option does not affect whether or not you will
6910 receive replies from multicast group members.
6912 You must be very careful to NOT use a multicast address which
6913 is already in use by another group of caches.
6915 If you are unsure about multicast, please read the Multicast
6916 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
6918 Usage: mcast_groups 239.128.16.128 224.0.1.20
6920 By default, Squid doesn't listen on any multicast groups.
6923 NAME: mcast_miss_addr
6924 IFDEF: MULTICAST_MISS_STREAM
6926 LOC: Config.mcast_miss.addr
6928 DEFAULT_DOC: disabled.
6930 If you enable this option, every "cache miss" URL will
6931 be sent out on the specified multicast address.
6933 Do not enable this option unless you are are absolutely
6934 certain you understand what you are doing.
6937 NAME: mcast_miss_ttl
6938 IFDEF: MULTICAST_MISS_STREAM
6940 LOC: Config.mcast_miss.ttl
6943 This is the time-to-live value for packets multicasted
6944 when multicasting off cache miss URLs is enabled. By
6945 default this is set to 'site scope', i.e. 16.
6948 NAME: mcast_miss_port
6949 IFDEF: MULTICAST_MISS_STREAM
6951 LOC: Config.mcast_miss.port
6954 This is the port number to be used in conjunction with
6958 NAME: mcast_miss_encode_key
6959 IFDEF: MULTICAST_MISS_STREAM
6961 LOC: Config.mcast_miss.encode_key
6962 DEFAULT: XXXXXXXXXXXXXXXX
6964 The URLs that are sent in the multicast miss stream are
6965 encrypted. This is the encryption key.
6968 NAME: mcast_icp_query_timeout
6972 LOC: Config.Timeout.mcast_icp_query
6974 For multicast peers, Squid regularly sends out ICP "probes" to
6975 count how many other peers are listening on the given multicast
6976 address. This value specifies how long Squid should wait to
6977 count all the replies. The default is 2000 msec, or 2
6982 INTERNAL ICON OPTIONS
6983 -----------------------------------------------------------------------------
6986 NAME: icon_directory
6988 LOC: Config.icons.directory
6989 DEFAULT: @DEFAULT_ICON_DIR@
6991 Where the icons are stored. These are normally kept in
6995 NAME: global_internal_static
6997 LOC: Config.onoff.global_internal_static
7000 This directive controls is Squid should intercept all requests for
7001 /squid-internal-static/ no matter which host the URL is requesting
7002 (default on setting), or if nothing special should be done for
7003 such URLs (off setting). The purpose of this directive is to make
7004 icons etc work better in complex cache hierarchies where it may
7005 not always be possible for all corners in the cache mesh to reach
7006 the server generating a directory listing.
7009 NAME: short_icon_urls
7011 LOC: Config.icons.use_short_names
7014 If this is enabled Squid will use short URLs for icons.
7015 If disabled it will revert to the old behavior of including
7016 it's own name and port in the URL.
7018 If you run a complex cache hierarchy with a mix of Squid and
7019 other proxies you may need to disable this directive.
7024 -----------------------------------------------------------------------------
7027 NAME: error_directory
7029 LOC: Config.errorDirectory
7031 DEFAULT_DOC: Send error pages in the clients preferred language
7033 If you wish to create your own versions of the default
7034 error files to customize them to suit your company copy
7035 the error/template files to another directory and point
7038 WARNING: This option will disable multi-language support
7039 on error pages if used.
7041 The squid developers are interested in making squid available in
7042 a wide variety of languages. If you are making translations for a
7043 language that Squid does not currently provide please consider
7044 contributing your translation back to the project.
7045 http://wiki.squid-cache.org/Translations
7047 The squid developers working on translations are happy to supply drop-in
7048 translated error files in exchange for any new language contributions.
7051 NAME: error_default_language
7052 IFDEF: USE_ERR_LOCALES
7054 LOC: Config.errorDefaultLanguage
7056 DEFAULT_DOC: Generate English language pages.
7058 Set the default language which squid will send error pages in
7059 if no existing translation matches the clients language
7062 If unset (default) generic English will be used.
7064 The squid developers are interested in making squid available in
7065 a wide variety of languages. If you are interested in making
7066 translations for any language see the squid wiki for details.
7067 http://wiki.squid-cache.org/Translations
7070 NAME: error_log_languages
7071 IFDEF: USE_ERR_LOCALES
7073 LOC: Config.errorLogMissingLanguages
7076 Log to cache.log what languages users are attempting to
7077 auto-negotiate for translations.
7079 Successful negotiations are not logged. Only failures
7080 have meaning to indicate that Squid may need an upgrade
7081 of its error page translations.
7084 NAME: err_page_stylesheet
7086 LOC: Config.errorStylesheet
7087 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7089 CSS Stylesheet to pattern the display of Squid default error pages.
7091 For information on CSS see http://www.w3.org/Style/CSS/
7096 LOC: Config.errHtmlText
7099 HTML text to include in error messages. Make this a "mailto"
7100 URL to your admin address, or maybe just a link to your
7101 organizations Web page.
7103 To include this in your error messages, you must rewrite
7104 the error template files (found in the "errors" directory).
7105 Wherever you want the 'err_html_text' line to appear,
7106 insert a %L tag in the error template file.
7109 NAME: email_err_data
7112 LOC: Config.onoff.emailErrData
7115 If enabled, information about the occurred error will be
7116 included in the mailto links of the ERR pages (if %W is set)
7117 so that the email body contains the data.
7118 Syntax is <A HREF="mailto:%w%W">%w</A>
7123 LOC: Config.denyInfoList
7126 Usage: deny_info err_page_name acl
7127 or deny_info http://... acl
7128 or deny_info TCP_RESET acl
7130 This can be used to return a ERR_ page for requests which
7131 do not pass the 'http_access' rules. Squid remembers the last
7132 acl it evaluated in http_access, and if a 'deny_info' line exists
7133 for that ACL Squid returns a corresponding error page.
7135 The acl is typically the last acl on the http_access deny line which
7136 denied access. The exceptions to this rule are:
7137 - When Squid needs to request authentication credentials. It's then
7138 the first authentication related acl encountered
7139 - When none of the http_access lines matches. It's then the last
7140 acl processed on the last http_access line.
7141 - When the decision to deny access was made by an adaptation service,
7142 the acl name is the corresponding eCAP or ICAP service_name.
7144 NP: If providing your own custom error pages with error_directory
7145 you may also specify them by your custom file name:
7146 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7148 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7149 may be specified by prefixing the file name with the code and a colon.
7150 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7152 Alternatively you can tell Squid to reset the TCP connection
7153 by specifying TCP_RESET.
7155 Or you can specify an error URL or URL pattern. The browsers will
7156 get redirected to the specified URL after formatting tags have
7157 been replaced. Redirect will be done with 302 or 307 according to
7158 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7159 the URL. e.g. 303:http://example.com/
7162 %a - username (if available. Password NOT included)
7165 %E - Error description
7167 %H - Request domain name
7168 %i - Client IP Address
7170 %o - Message result from external ACL helper
7171 %p - Request Port number
7172 %P - Request Protocol name
7173 %R - Request URL path
7174 %T - Timestamp in RFC 1123 format
7175 %U - Full canonical URL from client
7176 (HTTPS URLs terminate with *)
7177 %u - Full canonical URL from client
7178 %w - Admin email from squid.conf
7180 %% - Literal percent (%) code
7185 OPTIONS INFLUENCING REQUEST FORWARDING
7186 -----------------------------------------------------------------------------
7189 NAME: nonhierarchical_direct
7191 LOC: Config.onoff.nonhierarchical_direct
7194 By default, Squid will send any non-hierarchical requests
7195 (matching hierarchy_stoplist or not cacheable request type) direct
7198 When this is set to "off", Squid will prefer to send these
7199 requests to parents.
7201 Note that in most configurations, by turning this off you will only
7202 add latency to these request without any improvement in global hit
7205 This option only sets a preference. If the parent is unavailable a
7206 direct connection to the origin server may still be attempted. To
7207 completely prevent direct connections use never_direct.
7212 LOC: Config.onoff.prefer_direct
7215 Normally Squid tries to use parents for most requests. If you for some
7216 reason like it to first try going direct and only use a parent if
7217 going direct fails set this to on.
7219 By combining nonhierarchical_direct off and prefer_direct on you
7220 can set up Squid to use a parent as a backup path if going direct
7223 Note: If you want Squid to use parents for all requests see
7224 the never_direct directive. prefer_direct only modifies how Squid
7225 acts on cacheable requests.
7230 LOC: Config.accessList.AlwaysDirect
7232 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7234 Usage: always_direct allow|deny [!]aclname ...
7236 Here you can use ACL elements to specify requests which should
7237 ALWAYS be forwarded by Squid to the origin servers without using
7238 any peers. For example, to always directly forward requests for
7239 local servers ignoring any parents or siblings you may have use
7242 acl local-servers dstdomain my.domain.net
7243 always_direct allow local-servers
7245 To always forward FTP requests directly, use
7248 always_direct allow FTP
7250 NOTE: There is a similar, but opposite option named
7251 'never_direct'. You need to be aware that "always_direct deny
7252 foo" is NOT the same thing as "never_direct allow foo". You
7253 may need to use a deny rule to exclude a more-specific case of
7254 some other rule. Example:
7256 acl local-external dstdomain external.foo.net
7257 acl local-servers dstdomain .foo.net
7258 always_direct deny local-external
7259 always_direct allow local-servers
7261 NOTE: If your goal is to make the client forward the request
7262 directly to the origin server bypassing Squid then this needs
7263 to be done in the client configuration. Squid configuration
7264 can only tell Squid how Squid should fetch the object.
7266 NOTE: This directive is not related to caching. The replies
7267 is cached as usual even if you use always_direct. To not cache
7268 the replies see the 'cache' directive.
7270 This clause supports both fast and slow acl types.
7271 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7276 LOC: Config.accessList.NeverDirect
7278 DEFAULT_DOC: Allow DNS results to be used for this request.
7280 Usage: never_direct allow|deny [!]aclname ...
7282 never_direct is the opposite of always_direct. Please read
7283 the description for always_direct if you have not already.
7285 With 'never_direct' you can use ACL elements to specify
7286 requests which should NEVER be forwarded directly to origin
7287 servers. For example, to force the use of a proxy for all
7288 requests, except those in your local domain use something like:
7290 acl local-servers dstdomain .foo.net
7291 never_direct deny local-servers
7292 never_direct allow all
7294 or if Squid is inside a firewall and there are local intranet
7295 servers inside the firewall use something like:
7297 acl local-intranet dstdomain .foo.net
7298 acl local-external dstdomain external.foo.net
7299 always_direct deny local-external
7300 always_direct allow local-intranet
7301 never_direct allow all
7303 This clause supports both fast and slow acl types.
7304 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7308 ADVANCED NETWORKING OPTIONS
7309 -----------------------------------------------------------------------------
7312 NAME: incoming_udp_average incoming_icp_average
7315 LOC: Config.comm_incoming.udp.average
7317 Heavy voodoo here. I can't even believe you are reading this.
7318 Are you crazy? Don't even think about adjusting these unless
7319 you understand the algorithms in comm_select.c first!
7322 NAME: incoming_tcp_average incoming_http_average
7325 LOC: Config.comm_incoming.tcp.average
7327 Heavy voodoo here. I can't even believe you are reading this.
7328 Are you crazy? Don't even think about adjusting these unless
7329 you understand the algorithms in comm_select.c first!
7332 NAME: incoming_dns_average
7335 LOC: Config.comm_incoming.dns.average
7337 Heavy voodoo here. I can't even believe you are reading this.
7338 Are you crazy? Don't even think about adjusting these unless
7339 you understand the algorithms in comm_select.c first!
7342 NAME: min_udp_poll_cnt min_icp_poll_cnt
7345 LOC: Config.comm_incoming.udp.min_poll
7347 Heavy voodoo here. I can't even believe you are reading this.
7348 Are you crazy? Don't even think about adjusting these unless
7349 you understand the algorithms in comm_select.c first!
7352 NAME: min_dns_poll_cnt
7355 LOC: Config.comm_incoming.dns.min_poll
7357 Heavy voodoo here. I can't even believe you are reading this.
7358 Are you crazy? Don't even think about adjusting these unless
7359 you understand the algorithms in comm_select.c first!
7362 NAME: min_tcp_poll_cnt min_http_poll_cnt
7365 LOC: Config.comm_incoming.tcp.min_poll
7367 Heavy voodoo here. I can't even believe you are reading this.
7368 Are you crazy? Don't even think about adjusting these unless
7369 you understand the algorithms in comm_select.c first!
7375 LOC: Config.accept_filter
7379 The name of an accept(2) filter to install on Squid's
7380 listen socket(s). This feature is perhaps specific to
7381 FreeBSD and requires support in the kernel.
7383 The 'httpready' filter delays delivering new connections
7384 to Squid until a full HTTP request has been received.
7385 See the accf_http(9) man page for details.
7387 The 'dataready' filter delays delivering new connections
7388 to Squid until there is some data to process.
7389 See the accf_dataready(9) man page for details.
7393 The 'data' filter delays delivering of new connections
7394 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
7395 You may optionally specify a number of seconds to wait by
7396 'data=N' where N is the number of seconds. Defaults to 30
7397 if not specified. See the tcp(7) man page for details.
7400 accept_filter httpready
7405 NAME: client_ip_max_connections
7407 LOC: Config.client_ip_max_connections
7409 DEFAULT_DOC: No limit.
7411 Set an absolute limit on the number of connections a single
7412 client IP can use. Any more than this and Squid will begin to drop
7413 new connections from the client until it closes some links.
7415 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
7416 connections from the client. For finer control use the ACL access controls.
7418 Requires client_db to be enabled (the default).
7420 WARNING: This may noticably slow down traffic received via external proxies
7421 or NAT devices and cause them to rebound error messages back to their clients.
7424 NAME: tcp_recv_bufsize
7428 DEFAULT_DOC: Use operating system TCP defaults.
7429 LOC: Config.tcpRcvBufsz
7431 Size of receive buffer to set for TCP sockets. Probably just
7432 as easy to change your kernel's default.
7433 Omit from squid.conf to use the default buffer size.
7438 -----------------------------------------------------------------------------
7445 LOC: Adaptation::Icap::TheConfig.onoff
7448 If you want to enable the ICAP module support, set this to on.
7451 NAME: icap_connect_timeout
7454 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
7457 This parameter specifies how long to wait for the TCP connect to
7458 the requested ICAP server to complete before giving up and either
7459 terminating the HTTP transaction or bypassing the failure.
7461 The default for optional services is peer_connect_timeout.
7462 The default for essential services is connect_timeout.
7463 If this option is explicitly set, its value applies to all services.
7466 NAME: icap_io_timeout
7470 DEFAULT_DOC: Use read_timeout.
7471 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
7474 This parameter specifies how long to wait for an I/O activity on
7475 an established, active ICAP connection before giving up and
7476 either terminating the HTTP transaction or bypassing the
7480 NAME: icap_service_failure_limit
7481 COMMENT: limit [in memory-depth time-units]
7482 TYPE: icap_service_failure_limit
7484 LOC: Adaptation::Icap::TheConfig
7487 The limit specifies the number of failures that Squid tolerates
7488 when establishing a new TCP connection with an ICAP service. If
7489 the number of failures exceeds the limit, the ICAP service is
7490 not used for new ICAP requests until it is time to refresh its
7493 A negative value disables the limit. Without the limit, an ICAP
7494 service will not be considered down due to connectivity failures
7495 between ICAP OPTIONS requests.
7497 Squid forgets ICAP service failures older than the specified
7498 value of memory-depth. The memory fading algorithm
7499 is approximate because Squid does not remember individual
7500 errors but groups them instead, splitting the option
7501 value into ten time slots of equal length.
7503 When memory-depth is 0 and by default this option has no
7504 effect on service failure expiration.
7506 Squid always forgets failures when updating service settings
7507 using an ICAP OPTIONS transaction, regardless of this option
7511 # suspend service usage after 10 failures in 5 seconds:
7512 icap_service_failure_limit 10 in 5 seconds
7515 NAME: icap_service_revival_delay
7518 LOC: Adaptation::Icap::TheConfig.service_revival_delay
7521 The delay specifies the number of seconds to wait after an ICAP
7522 OPTIONS request failure before requesting the options again. The
7523 failed ICAP service is considered "down" until fresh OPTIONS are
7526 The actual delay cannot be smaller than the hardcoded minimum
7527 delay of 30 seconds.
7530 NAME: icap_preview_enable
7534 LOC: Adaptation::Icap::TheConfig.preview_enable
7537 The ICAP Preview feature allows the ICAP server to handle the
7538 HTTP message by looking only at the beginning of the message body
7539 or even without receiving the body at all. In some environments,
7540 previews greatly speedup ICAP processing.
7542 During an ICAP OPTIONS transaction, the server may tell Squid what
7543 HTTP messages should be previewed and how big the preview should be.
7544 Squid will not use Preview if the server did not request one.
7546 To disable ICAP Preview for all ICAP services, regardless of
7547 individual ICAP server OPTIONS responses, set this option to "off".
7549 icap_preview_enable off
7552 NAME: icap_preview_size
7555 LOC: Adaptation::Icap::TheConfig.preview_size
7557 DEFAULT_DOC: No preview sent.
7559 The default size of preview data to be sent to the ICAP server.
7560 This value might be overwritten on a per server basis by OPTIONS requests.
7563 NAME: icap_206_enable
7567 LOC: Adaptation::Icap::TheConfig.allow206_enable
7570 206 (Partial Content) responses is an ICAP extension that allows the
7571 ICAP agents to optionally combine adapted and original HTTP message
7572 content. The decision to combine is postponed until the end of the
7573 ICAP response. Squid supports Partial Content extension by default.
7575 Activation of the Partial Content extension is negotiated with each
7576 ICAP service during OPTIONS exchange. Most ICAP servers should handle
7577 negotation correctly even if they do not support the extension, but
7578 some might fail. To disable Partial Content support for all ICAP
7579 services and to avoid any negotiation, set this option to "off".
7585 NAME: icap_default_options_ttl
7588 LOC: Adaptation::Icap::TheConfig.default_options_ttl
7591 The default TTL value for ICAP OPTIONS responses that don't have
7592 an Options-TTL header.
7595 NAME: icap_persistent_connections
7599 LOC: Adaptation::Icap::TheConfig.reuse_connections
7602 Whether or not Squid should use persistent connections to
7606 NAME: adaptation_send_client_ip icap_send_client_ip
7608 IFDEF: USE_ADAPTATION
7610 LOC: Adaptation::Config::send_client_ip
7613 If enabled, Squid shares HTTP client IP information with adaptation
7614 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
7615 For eCAP, Squid sets the libecap::metaClientIp transaction option.
7617 See also: adaptation_uses_indirect_client
7620 NAME: adaptation_send_username icap_send_client_username
7622 IFDEF: USE_ADAPTATION
7624 LOC: Adaptation::Config::send_username
7627 This sends authenticated HTTP client username (if available) to
7628 the adaptation service.
7630 For ICAP, the username value is encoded based on the
7631 icap_client_username_encode option and is sent using the header
7632 specified by the icap_client_username_header option.
7635 NAME: icap_client_username_header
7638 LOC: Adaptation::Icap::TheConfig.client_username_header
7639 DEFAULT: X-Client-Username
7641 ICAP request header name to use for adaptation_send_username.
7644 NAME: icap_client_username_encode
7648 LOC: Adaptation::Icap::TheConfig.client_username_encode
7651 Whether to base64 encode the authenticated client username.
7655 TYPE: icap_service_type
7657 LOC: Adaptation::Icap::TheConfig
7660 Defines a single ICAP service using the following format:
7662 icap_service id vectoring_point uri [option ...]
7665 an opaque identifier or name which is used to direct traffic to
7666 this specific service. Must be unique among all adaptation
7667 services in squid.conf.
7669 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7670 This specifies at which point of transaction processing the
7671 ICAP service should be activated. *_postcache vectoring points
7672 are not yet supported.
7674 uri: icap://servername:port/servicepath
7675 ICAP server and service location.
7677 ICAP does not allow a single service to handle both REQMOD and RESPMOD
7678 transactions. Squid does not enforce that requirement. You can specify
7679 services with the same service_url and different vectoring_points. You
7680 can even specify multiple identical services as long as their
7681 service_names differ.
7684 Service options are separated by white space. ICAP services support
7685 the following name=value options:
7688 If set to 'on' or '1', the ICAP service is treated as
7689 optional. If the service cannot be reached or malfunctions,
7690 Squid will try to ignore any errors and process the message as
7691 if the service was not enabled. No all ICAP errors can be
7692 bypassed. If set to 0, the ICAP service is treated as
7693 essential and all ICAP errors will result in an error page
7694 returned to the HTTP client.
7696 Bypass is off by default: services are treated as essential.
7699 If set to 'on' or '1', the ICAP service is allowed to
7700 dynamically change the current message adaptation plan by
7701 returning a chain of services to be used next. The services
7702 are specified using the X-Next-Services ICAP response header
7703 value, formatted as a comma-separated list of service names.
7704 Each named service should be configured in squid.conf. Other
7705 services are ignored. An empty X-Next-Services value results
7706 in an empty plan which ends the current adaptation.
7708 Dynamic adaptation plan may cross or cover multiple supported
7709 vectoring points in their natural processing order.
7711 Routing is not allowed by default: the ICAP X-Next-Services
7712 response header is ignored.
7715 Only has effect on split-stack systems. The default on those systems
7716 is to use IPv4-only connections. When set to 'on' this option will
7717 make Squid use IPv6-only connections to contact this ICAP service.
7719 on-overload=block|bypass|wait|force
7720 If the service Max-Connections limit has been reached, do
7721 one of the following for each new ICAP transaction:
7722 * block: send an HTTP error response to the client
7723 * bypass: ignore the "over-connected" ICAP service
7724 * wait: wait (in a FIFO queue) for an ICAP connection slot
7725 * force: proceed, ignoring the Max-Connections limit
7727 In SMP mode with N workers, each worker assumes the service
7728 connection limit is Max-Connections/N, even though not all
7729 workers may use a given service.
7731 The default value is "bypass" if service is bypassable,
7732 otherwise it is set to "wait".
7736 Use the given number as the Max-Connections limit, regardless
7737 of the Max-Connections value given by the service, if any.
7739 Older icap_service format without optional named parameters is
7740 deprecated but supported for backward compatibility.
7743 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
7744 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
7748 TYPE: icap_class_type
7753 This deprecated option was documented to define an ICAP service
7754 chain, even though it actually defined a set of similar, redundant
7755 services, and the chains were not supported.
7757 To define a set of redundant services, please use the
7758 adaptation_service_set directive. For service chains, use
7759 adaptation_service_chain.
7763 TYPE: icap_access_type
7768 This option is deprecated. Please use adaptation_access, which
7769 has the same ICAP functionality, but comes with better
7770 documentation, and eCAP support.
7775 -----------------------------------------------------------------------------
7782 LOC: Adaptation::Ecap::TheConfig.onoff
7785 Controls whether eCAP support is enabled.
7789 TYPE: ecap_service_type
7791 LOC: Adaptation::Ecap::TheConfig
7794 Defines a single eCAP service
7796 ecap_service id vectoring_point uri [option ...]
7799 an opaque identifier or name which is used to direct traffic to
7800 this specific service. Must be unique among all adaptation
7801 services in squid.conf.
7803 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7804 This specifies at which point of transaction processing the
7805 eCAP service should be activated. *_postcache vectoring points
7806 are not yet supported.
7808 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
7809 Squid uses the eCAP service URI to match this configuration
7810 line with one of the dynamically loaded services. Each loaded
7811 eCAP service must have a unique URI. Obtain the right URI from
7812 the service provider.
7815 Service options are separated by white space. eCAP services support
7816 the following name=value options:
7819 If set to 'on' or '1', the eCAP service is treated as optional.
7820 If the service cannot be reached or malfunctions, Squid will try
7821 to ignore any errors and process the message as if the service
7822 was not enabled. No all eCAP errors can be bypassed.
7823 If set to 'off' or '0', the eCAP service is treated as essential
7824 and all eCAP errors will result in an error page returned to the
7827 Bypass is off by default: services are treated as essential.
7830 If set to 'on' or '1', the eCAP service is allowed to
7831 dynamically change the current message adaptation plan by
7832 returning a chain of services to be used next.
7834 Dynamic adaptation plan may cross or cover multiple supported
7835 vectoring points in their natural processing order.
7837 Routing is not allowed by default.
7839 Older ecap_service format without optional named parameters is
7840 deprecated but supported for backward compatibility.
7844 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
7845 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
7848 NAME: loadable_modules
7850 IFDEF: USE_LOADABLE_MODULES
7851 LOC: Config.loadable_module_names
7854 Instructs Squid to load the specified dynamic module(s) or activate
7855 preloaded module(s).
7857 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
7861 MESSAGE ADAPTATION OPTIONS
7862 -----------------------------------------------------------------------------
7865 NAME: adaptation_service_set
7866 TYPE: adaptation_service_set_type
7867 IFDEF: USE_ADAPTATION
7872 Configures an ordered set of similar, redundant services. This is
7873 useful when hot standby or backup adaptation servers are available.
7875 adaptation_service_set set_name service_name1 service_name2 ...
7877 The named services are used in the set declaration order. The first
7878 applicable adaptation service from the set is used first. The next
7879 applicable service is tried if and only if the transaction with the
7880 previous service fails and the message waiting to be adapted is still
7883 When adaptation starts, broken services are ignored as if they were
7884 not a part of the set. A broken service is a down optional service.
7886 The services in a set must be attached to the same vectoring point
7887 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7889 If all services in a set are optional then adaptation failures are
7890 bypassable. If all services in the set are essential, then a
7891 transaction failure with one service may still be retried using
7892 another service from the set, but when all services fail, the master
7893 transaction fails as well.
7895 A set may contain a mix of optional and essential services, but that
7896 is likely to lead to surprising results because broken services become
7897 ignored (see above), making previously bypassable failures fatal.
7898 Technically, it is the bypassability of the last failed service that
7901 See also: adaptation_access adaptation_service_chain
7904 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
7905 adaptation service_set svcLogger loggerLocal loggerRemote
7908 NAME: adaptation_service_chain
7909 TYPE: adaptation_service_chain_type
7910 IFDEF: USE_ADAPTATION
7915 Configures a list of complementary services that will be applied
7916 one-by-one, forming an adaptation chain or pipeline. This is useful
7917 when Squid must perform different adaptations on the same message.
7919 adaptation_service_chain chain_name service_name1 svc_name2 ...
7921 The named services are used in the chain declaration order. The first
7922 applicable adaptation service from the chain is used first. The next
7923 applicable service is applied to the successful adaptation results of
7924 the previous service in the chain.
7926 When adaptation starts, broken services are ignored as if they were
7927 not a part of the chain. A broken service is a down optional service.
7929 Request satisfaction terminates the adaptation chain because Squid
7930 does not currently allow declaration of RESPMOD services at the
7931 "reqmod_precache" vectoring point (see icap_service or ecap_service).
7933 The services in a chain must be attached to the same vectoring point
7934 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7936 A chain may contain a mix of optional and essential services. If an
7937 essential adaptation fails (or the failure cannot be bypassed for
7938 other reasons), the master transaction fails. Otherwise, the failure
7939 is bypassed as if the failed adaptation service was not in the chain.
7941 See also: adaptation_access adaptation_service_set
7944 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
7947 NAME: adaptation_access
7948 TYPE: adaptation_access_type
7949 IFDEF: USE_ADAPTATION
7952 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
7954 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
7956 adaptation_access service_name allow|deny [!]aclname...
7957 adaptation_access set_name allow|deny [!]aclname...
7959 At each supported vectoring point, the adaptation_access
7960 statements are processed in the order they appear in this
7961 configuration file. Statements pointing to the following services
7962 are ignored (i.e., skipped without checking their ACL):
7964 - services serving different vectoring points
7965 - "broken-but-bypassable" services
7966 - "up" services configured to ignore such transactions
7967 (e.g., based on the ICAP Transfer-Ignore header).
7969 When a set_name is used, all services in the set are checked
7970 using the same rules, to find the first applicable one. See
7971 adaptation_service_set for details.
7973 If an access list is checked and there is a match, the
7974 processing stops: For an "allow" rule, the corresponding
7975 adaptation service is used for the transaction. For a "deny"
7976 rule, no adaptation service is activated.
7978 It is currently not possible to apply more than one adaptation
7979 service at the same vectoring point to the same HTTP transaction.
7981 See also: icap_service and ecap_service
7984 adaptation_access service_1 allow all
7987 NAME: adaptation_service_iteration_limit
7989 IFDEF: USE_ADAPTATION
7990 LOC: Adaptation::Config::service_iteration_limit
7993 Limits the number of iterations allowed when applying adaptation
7994 services to a message. If your longest adaptation set or chain
7995 may have more than 16 services, increase the limit beyond its
7996 default value of 16. If detecting infinite iteration loops sooner
7997 is critical, make the iteration limit match the actual number
7998 of services in your longest adaptation set or chain.
8000 Infinite adaptation loops are most likely with routing services.
8002 See also: icap_service routing=1
8005 NAME: adaptation_masterx_shared_names
8007 IFDEF: USE_ADAPTATION
8008 LOC: Adaptation::Config::masterx_shared_name
8011 For each master transaction (i.e., the HTTP request and response
8012 sequence, including all related ICAP and eCAP exchanges), Squid
8013 maintains a table of metadata. The table entries are (name, value)
8014 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8015 with the master transaction.
8017 This option specifies the table entry names that Squid must accept
8018 from and forward to the adaptation transactions.
8020 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8021 shared table by returning an ICAP header field with a name
8022 specified in adaptation_masterx_shared_names.
8024 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8025 shared table by implementing the libecap::visitEachOption() API
8026 to provide an option with a name specified in
8027 adaptation_masterx_shared_names.
8029 Squid will store and forward the set entry to subsequent adaptation
8030 transactions within the same master transaction scope.
8032 Only one shared entry name is supported at this time.
8035 # share authentication information among ICAP services
8036 adaptation_masterx_shared_names X-Subscriber-ID
8039 NAME: adaptation_meta
8041 IFDEF: USE_ADAPTATION
8042 LOC: Adaptation::Config::metaHeaders
8045 This option allows Squid administrator to add custom ICAP request
8046 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8047 Use it to pass custom authentication tokens and other
8048 transaction-state related meta information to an ICAP/eCAP service.
8050 The addition of a meta header is ACL-driven:
8051 adaptation_meta name value [!]aclname ...
8053 Processing for a given header name stops after the first ACL list match.
8054 Thus, it is impossible to add two headers with the same name. If no ACL
8055 lists match for a given header name, no such header is added. For
8058 # do not debug transactions except for those that need debugging
8059 adaptation_meta X-Debug 1 needs_debugging
8061 # log all transactions except for those that must remain secret
8062 adaptation_meta X-Log 1 !keep_secret
8064 # mark transactions from users in the "G 1" group
8065 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8067 The "value" parameter may be a regular squid.conf token or a "double
8068 quoted string". Within the quoted string, use backslash (\) to escape
8069 any character, which is currently only useful for escaping backslashes
8070 and double quotes. For example,
8071 "this string has one backslash (\\) and two \"quotes\""
8073 Used adaptation_meta header values may be logged via %note
8074 logformat code. If multiple adaptation_meta headers with the same name
8075 are used during master transaction lifetime, the header values are
8076 logged in the order they were used and duplicate values are ignored
8077 (only the first repeated value will be logged).
8083 LOC: Adaptation::Icap::TheConfig.repeat
8084 DEFAULT_IF_NONE: deny all
8086 This ACL determines which retriable ICAP transactions are
8087 retried. Transactions that received a complete ICAP response
8088 and did not have to consume or produce HTTP bodies to receive
8089 that response are usually retriable.
8091 icap_retry allow|deny [!]aclname ...
8093 Squid automatically retries some ICAP I/O timeouts and errors
8094 due to persistent connection race conditions.
8096 See also: icap_retry_limit
8099 NAME: icap_retry_limit
8102 LOC: Adaptation::Icap::TheConfig.repeat_limit
8104 DEFAULT_DOC: No retries are allowed.
8106 Limits the number of retries allowed.
8108 Communication errors due to persistent connection race
8109 conditions are unavoidable, automatically retried, and do not
8110 count against this limit.
8112 See also: icap_retry
8118 -----------------------------------------------------------------------------
8121 NAME: check_hostnames
8124 LOC: Config.onoff.check_hostnames
8126 For security and stability reasons Squid can check
8127 hostnames for Internet standard RFC compliance. If you want
8128 Squid to perform these checks turn this directive on.
8131 NAME: allow_underscore
8134 LOC: Config.onoff.allow_underscore
8136 Underscore characters is not strictly allowed in Internet hostnames
8137 but nevertheless used by many sites. Set this to off if you want
8138 Squid to be strict about the standard.
8139 This check is performed only when check_hostnames is set to on.
8142 NAME: cache_dns_program
8144 IFDEF: USE_DNSHELPER
8145 DEFAULT: @DEFAULT_DNSSERVER@
8146 LOC: Config.Program.dnsserver
8148 Specify the location of the executable for dnslookup process.
8152 TYPE: HelperChildConfig
8153 IFDEF: USE_DNSHELPER
8154 DEFAULT: 32 startup=1 idle=1
8155 LOC: Config.dnsChildren
8157 The maximum number of processes spawn to service DNS name lookups.
8158 If you limit it too few Squid will have to wait for them to process
8159 a backlog of requests, slowing it down. If you allow too many they
8160 will use RAM and other system resources noticably.
8161 The maximum this may be safely set to is 32.
8163 The startup= and idle= options allow some measure of skew in your
8168 Sets a minimum of how many processes are to be spawned when Squid
8169 starts or reconfigures. When set to zero the first request will
8170 cause spawning of the first child process to handle it.
8172 Starting too few will cause an initial slowdown in traffic as Squid
8173 attempts to simultaneously spawn enough processes to cope.
8177 Sets a minimum of how many processes Squid is to try and keep available
8178 at all times. When traffic begins to rise above what the existing
8179 processes can handle this many more will be spawned up to the maximum
8180 configured. A minimum setting of 1 is required.
8183 NAME: dns_retransmit_interval
8186 LOC: Config.Timeout.idns_retransmit
8187 IFDEF: !USE_DNSHELPER
8189 Initial retransmit interval for DNS queries. The interval is
8190 doubled each time all configured DNS servers have been tried.
8196 LOC: Config.Timeout.idns_query
8197 IFDEF: !USE_DNSHELPER
8199 DNS Query timeout. If no response is received to a DNS query
8200 within this time all DNS servers for the queried domain
8201 are assumed to be unavailable.
8204 NAME: dns_packet_max
8206 DEFAULT_DOC: EDNS disabled
8208 LOC: Config.dns.packet_max
8209 IFDEF: !USE_DNSHELPER
8211 Maximum number of bytes packet size to advertise via EDNS.
8212 Set to "none" to disable EDNS large packet support.
8214 For legacy reasons DNS UDP replies will default to 512 bytes which
8215 is too small for many responses. EDNS provides a means for Squid to
8216 negotiate receiving larger responses back immediately without having
8217 to failover with repeat requests. Responses larger than this limit
8218 will retain the old behaviour of failover to TCP DNS.
8220 Squid has no real fixed limit internally, but allowing packet sizes
8221 over 1500 bytes requires network jumbogram support and is usually not
8224 WARNING: The RFC also indicates that some older resolvers will reply
8225 with failure of the whole request if the extension is added. Some
8226 resolvers have already been identified which will reply with mangled
8227 EDNS response on occasion. Usually in response to many-KB jumbogram
8228 sizes being advertised by Squid.
8229 Squid will currently treat these both as an unable-to-resolve domain
8230 even if it would be resolvable without EDNS.
8237 DEFAULT_DOC: Search for single-label domain names is disabled.
8238 LOC: Config.onoff.res_defnames
8240 Normally the RES_DEFNAMES resolver option is disabled
8241 (see res_init(3)). This prevents caches in a hierarchy
8242 from interpreting single-component hostnames locally. To allow
8243 Squid to handle single-component names, enable this option.
8246 NAME: dns_nameservers
8249 DEFAULT_DOC: Use operating system definitions
8250 LOC: Config.dns_nameservers
8252 Use this if you want to specify a list of DNS name servers
8253 (IP addresses) to use instead of those given in your
8254 /etc/resolv.conf file.
8256 On Windows platforms, if no value is specified here or in
8257 the /etc/resolv.conf file, the list of DNS name servers are
8258 taken from the Windows registry, both static and dynamic DHCP
8259 configurations are supported.
8261 Example: dns_nameservers 10.0.0.1 192.172.0.4
8266 DEFAULT: @DEFAULT_HOSTS@
8267 LOC: Config.etcHostsPath
8269 Location of the host-local IP name-address associations
8270 database. Most Operating Systems have such a file on different
8272 - Un*X & Linux: /etc/hosts
8273 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
8274 (%SystemRoot% value install default is c:\winnt)
8275 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
8276 (%SystemRoot% value install default is c:\windows)
8277 - Windows 9x/Me: %windir%\hosts
8278 (%windir% value is usually c:\windows)
8279 - Cygwin: /etc/hosts
8281 The file contains newline-separated definitions, in the
8282 form ip_address_in_dotted_form name [name ...] names are
8283 whitespace-separated. Lines beginning with an hash (#)
8284 character are comments.
8286 The file is checked at startup and upon configuration.
8287 If set to 'none', it won't be checked.
8288 If append_domain is used, that domain will be added to
8289 domain-local (i.e. not containing any dot character) host
8295 LOC: Config.appendDomain
8297 DEFAULT_DOC: Use operating system definitions
8299 Appends local domain name to hostnames without any dots in
8300 them. append_domain must begin with a period.
8302 Be warned there are now Internet names with no dots in
8303 them using only top-domain names, so setting this may
8304 cause some Internet sites to become unavailable.
8307 append_domain .yourdomain.com
8310 NAME: ignore_unknown_nameservers
8312 LOC: Config.onoff.ignore_unknown_nameservers
8314 IFDEF: !USE_DNSHELPER
8316 By default Squid checks that DNS responses are received
8317 from the same IP addresses they are sent to. If they
8318 don't match, Squid ignores the response and writes a warning
8319 message to cache.log. You can allow responses from unknown
8320 nameservers by setting this option to 'off'.
8326 LOC: Config.dns.v4_first
8327 IFDEF: !USE_DNSHELPER
8329 With the IPv6 Internet being as fast or faster than IPv4 Internet
8330 for most networks Squid prefers to contact websites over IPv6.
8332 This option reverses the order of preference to make Squid contact
8333 dual-stack websites over IPv4 first. Squid will still perform both
8334 IPv6 and IPv4 DNS lookups before connecting.
8337 This option will restrict the situations under which IPv6
8338 connectivity is used (and tested). Hiding network problems
8339 which would otherwise be detected and warned about.
8343 COMMENT: (number of entries)
8346 LOC: Config.ipcache.size
8348 Maximum number of DNS IP cache entries.
8355 LOC: Config.ipcache.low
8362 LOC: Config.ipcache.high
8364 The size, low-, and high-water marks for the IP cache.
8367 NAME: fqdncache_size
8368 COMMENT: (number of entries)
8371 LOC: Config.fqdncache.size
8373 Maximum number of FQDN cache entries.
8378 -----------------------------------------------------------------------------
8385 LOC: Config.onoff.mem_pools
8387 If set, Squid will keep pools of allocated (but unused) memory
8388 available for future use. If memory is a premium on your
8389 system and you believe your malloc library outperforms Squid
8390 routines, disable this.
8393 NAME: memory_pools_limit
8397 LOC: Config.MemPools.limit
8399 Used only with memory_pools on:
8400 memory_pools_limit 50 MB
8402 If set to a non-zero value, Squid will keep at most the specified
8403 limit of allocated (but unused) memory in memory pools. All free()
8404 requests that exceed this limit will be handled by your malloc
8405 library. Squid does not pre-allocate any memory, just safe-keeps
8406 objects that otherwise would be free()d. Thus, it is safe to set
8407 memory_pools_limit to a reasonably high value even if your
8408 configuration will use less memory.
8410 If set to none, Squid will keep all memory it can. That is, there
8411 will be no limit on the total amount of memory used for safe-keeping.
8413 To disable memory allocation optimization, do not set
8414 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
8416 An overhead for maintaining memory pools is not taken into account
8417 when the limit is checked. This overhead is close to four bytes per
8418 object kept. However, pools may actually _save_ memory because of
8419 reduced memory thrashing in your malloc library.
8423 COMMENT: on|off|transparent|truncate|delete
8426 LOC: opt_forwarded_for
8428 If set to "on", Squid will append your client's IP address
8429 in the HTTP requests it forwards. By default it looks like:
8431 X-Forwarded-For: 192.1.2.3
8433 If set to "off", it will appear as
8435 X-Forwarded-For: unknown
8437 If set to "transparent", Squid will not alter the
8438 X-Forwarded-For header in any way.
8440 If set to "delete", Squid will delete the entire
8441 X-Forwarded-For header.
8443 If set to "truncate", Squid will remove all existing
8444 X-Forwarded-For entries, and place the client IP as the sole entry.
8447 NAME: cachemgr_passwd
8448 TYPE: cachemgrpasswd
8450 DEFAULT_DOC: No password. Actions which require password are denied.
8451 LOC: Config.passwd_list
8453 Specify passwords for cachemgr operations.
8455 Usage: cachemgr_passwd password action action ...
8457 Some valid actions are (see cache manager menu for a full list):
8497 * Indicates actions which will not be performed without a
8498 valid password, others can be performed if not listed here.
8500 To disable an action, set the password to "disable".
8501 To allow performing an action without a password, set the
8504 Use the keyword "all" to set the same password for all actions.
8507 cachemgr_passwd secret shutdown
8508 cachemgr_passwd lesssssssecret info stats/objects
8509 cachemgr_passwd disable all
8516 LOC: Config.onoff.client_db
8518 If you want to disable collecting per-client statistics,
8519 turn off client_db here.
8522 NAME: refresh_all_ims
8526 LOC: Config.onoff.refresh_all_ims
8528 When you enable this option, squid will always check
8529 the origin server for an update when a client sends an
8530 If-Modified-Since request. Many browsers use IMS
8531 requests when the user requests a reload, and this
8532 ensures those clients receive the latest version.
8534 By default (off), squid may return a Not Modified response
8535 based on the age of the cached version.
8538 NAME: reload_into_ims
8539 IFDEF: USE_HTTP_VIOLATIONS
8543 LOC: Config.onoff.reload_into_ims
8545 When you enable this option, client no-cache or ``reload''
8546 requests will be changed to If-Modified-Since requests.
8547 Doing this VIOLATES the HTTP standard. Enabling this
8548 feature could make you liable for problems which it
8551 see also refresh_pattern for a more selective approach.
8554 NAME: connect_retries
8556 LOC: Config.connect_retries
8558 DEFAULT_DOC: Do not retry failed connections.
8560 This sets the maximum number of connection attempts made for each
8561 TCP connection. The connect_retries attempts must all still
8562 complete within the connection timeout period.
8564 The default is not to re-try if the first connection attempt fails.
8565 The (not recommended) maximum is 10 tries.
8567 A warning message will be generated if it is set to a too-high
8568 value and the configured value will be over-ridden.
8570 Note: These re-tries are in addition to forward_max_tries
8571 which limit how many different addresses may be tried to find
8575 NAME: retry_on_error
8577 LOC: Config.retry.onerror
8580 If set to ON Squid will automatically retry requests when
8581 receiving an error response with status 403 (Forbidden),
8582 500 (Internal Error), 501 or 503 (Service not available).
8583 Status 502 and 504 (Gateway errors) are always retried.
8585 This is mainly useful if you are in a complex cache hierarchy to
8586 work around access control errors.
8588 NOTE: This retry will attempt to find another working destination.
8589 Which is different from the server which just failed.
8592 NAME: as_whois_server
8594 LOC: Config.as_whois_server
8595 DEFAULT: whois.ra.net
8597 WHOIS server to query for AS numbers. NOTE: AS numbers are
8598 queried only when Squid starts up, not for every request.
8603 LOC: Config.onoff.offline
8606 Enable this option and Squid will never try to validate cached
8610 NAME: uri_whitespace
8611 TYPE: uri_whitespace
8612 LOC: Config.uri_whitespace
8615 What to do with requests that have whitespace characters in the
8618 strip: The whitespace characters are stripped out of the URL.
8619 This is the behavior recommended by RFC2396 and RFC3986
8620 for tolerant handling of generic URI.
8621 NOTE: This is one difference between generic URI and HTTP URLs.
8623 deny: The request is denied. The user receives an "Invalid
8625 This is the behaviour recommended by RFC2616 for safe
8626 handling of HTTP request URL.
8628 allow: The request is allowed and the URI is not changed. The
8629 whitespace characters remain in the URI. Note the
8630 whitespace is passed to redirector processes if they
8632 Note this may be considered a violation of RFC2616
8633 request parsing where whitespace is prohibited in the
8636 encode: The request is allowed and the whitespace characters are
8637 encoded according to RFC1738.
8639 chop: The request is allowed and the URI is chopped at the
8643 NOTE the current Squid implementation of encode and chop violates
8644 RFC2616 by not using a 301 redirect after altering the URL.
8649 LOC: Config.chroot_dir
8652 Specifies a directory where Squid should do a chroot() while
8653 initializing. This also causes Squid to fully drop root
8654 privileges after initializing. This means, for example, if you
8655 use a HTTP port less than 1024 and try to reconfigure, you may
8656 get an error saying that Squid can not open the port.
8659 NAME: balance_on_multiple_ip
8661 LOC: Config.onoff.balance_on_multiple_ip
8664 Modern IP resolvers in squid sort lookup results by preferred access.
8665 By default squid will use these IP in order and only rotates to
8666 the next listed when the most preffered fails.
8668 Some load balancing servers based on round robin DNS have been
8669 found not to preserve user session state across requests
8670 to different IP addresses.
8672 Enabling this directive Squid rotates IP's per request.
8675 NAME: pipeline_prefetch
8677 LOC: Config.onoff.pipeline_prefetch
8680 To boost the performance of pipelined requests to closer
8681 match that of a non-proxied environment Squid can try to fetch
8682 up to two requests in parallel from a pipeline.
8684 Defaults to off for bandwidth management and access logging
8687 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
8690 NAME: high_response_time_warning
8693 LOC: Config.warnings.high_rptm
8695 DEFAULT_DOC: disabled.
8697 If the one-minute median response time exceeds this value,
8698 Squid prints a WARNING with debug level 0 to get the
8699 administrators attention. The value is in milliseconds.
8702 NAME: high_page_fault_warning
8704 LOC: Config.warnings.high_pf
8706 DEFAULT_DOC: disabled.
8708 If the one-minute average page fault rate exceeds this
8709 value, Squid prints a WARNING with debug level 0 to get
8710 the administrators attention. The value is in page faults
8714 NAME: high_memory_warning
8716 LOC: Config.warnings.high_memory
8718 DEFAULT_DOC: disabled.
8720 If the memory usage (as determined by mallinfo) exceeds
8721 this amount, Squid prints a WARNING with debug level 0 to get
8722 the administrators attention.
8725 NAME: sleep_after_fork
8726 COMMENT: (microseconds)
8728 LOC: Config.sleep_after_fork
8731 When this is set to a non-zero value, the main Squid process
8732 sleeps the specified number of microseconds after a fork()
8733 system call. This sleep may help the situation where your
8734 system reports fork() failures due to lack of (virtual)
8735 memory. Note, however, if you have a lot of child
8736 processes, these sleep delays will add up and your
8737 Squid will not service requests for some amount of time
8738 until all the child processes have been started.
8739 On Windows value less then 1000 (1 milliseconds) are
8743 NAME: windows_ipaddrchangemonitor
8744 IFDEF: _SQUID_WINDOWS_
8748 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
8750 On Windows Squid by default will monitor IP address changes and will
8751 reconfigure itself after any detected event. This is very useful for
8752 proxies connected to internet with dial-up interfaces.
8753 In some cases (a Proxy server acting as VPN gateway is one) it could be
8754 desiderable to disable this behaviour setting this to 'off'.
8755 Note: after changing this, Squid service must be restarted.
8760 IFDEF: USE_SQUID_EUI
8762 LOC: Eui::TheConfig.euiLookup
8764 Whether to lookup the EUI or MAC address of a connected client.
8767 NAME: max_filedescriptors max_filedesc
8770 DEFAULT_DOC: Use operating system limits set by ulimit.
8771 LOC: Config.max_filedescriptors
8773 Reduce the maximum number of filedescriptors supported below
8774 the usual operating system defaults.
8776 Remove from squid.conf to inherit the current ulimit setting.
8778 Note: Changing this requires a restart of Squid. Also
8779 not all I/O types supports large values (eg on Windows).
8786 DEFAULT_DOC: SMP support disabled.
8788 Number of main Squid processes or "workers" to fork and maintain.
8789 0: "no daemon" mode, like running "squid -N ..."
8790 1: "no SMP" mode, start one main Squid process daemon (default)
8791 N: start N main Squid process daemons (i.e., SMP mode)
8793 In SMP mode, each worker does nearly all what a single Squid daemon
8794 does (e.g., listen on http_port and forward HTTP requests).
8797 NAME: cpu_affinity_map
8798 TYPE: CpuAffinityMap
8799 LOC: Config.cpuAffinityMap
8801 DEFAULT_DOC: Let operating system decide.
8803 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
8805 Sets 1:1 mapping between Squid processes and CPU cores. For example,
8807 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
8809 affects processes 1 through 4 only and places them on the first
8810 four even cores, starting with core #1.
8812 CPU cores are numbered starting from 1. Requires support for
8813 sched_getaffinity(2) and sched_setaffinity(2) system calls.
8815 Multiple cpu_affinity_map options are merged.
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