2 # SQUID Web Proxy Cache http://www.squid-cache.org/
3 # ----------------------------------------------------------
5 # Squid is the result of efforts by numerous individuals from
6 # the Internet community; see the CONTRIBUTORS file for full
7 # details. Many organizations have provided support for Squid's
8 # development; see the SPONSORS file for full details. Squid is
9 # Copyrighted (C) 2000 by the Regents of the University of
10 # California; see the COPYRIGHT file for full details. Squid
11 # incorporates software developed and/or copyrighted by other
12 # sources; see the CREDITS file for full details.
14 # This program is free software; you can redistribute it and/or modify
15 # it under the terms of the GNU General Public License as published by
16 # the Free Software Foundation; either version 2 of the License, or
17 # (at your option) any later version.
19 # This program is distributed in the hope that it will be useful,
20 # but WITHOUT ANY WARRANTY; without even the implied warranty of
21 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 # GNU General Public License for more details.
24 # You should have received a copy of the GNU General Public License
25 # along with this program; if not, write to the Free Software
26 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
31 ----------------------------
33 This is the documentation for the Squid configuration file.
34 This documentation can also be found online at:
35 http://www.squid-cache.org/Doc/config/
37 You may wish to look at the Squid home page and wiki for the
38 FAQ and other documentation:
39 http://www.squid-cache.org/
40 http://wiki.squid-cache.org/SquidFaq
41 http://wiki.squid-cache.org/ConfigExamples
43 This documentation shows what the defaults for various directives
44 happen to be. If you don't need to change the default, you should
45 leave the line out of your squid.conf in most cases.
47 In some cases "none" refers to no default setting at all,
48 while in other cases it refers to the value of the option
49 - the comments for that keyword indicate if this is the case.
54 Configuration options can be included using the "include" directive.
55 Include takes a list of files to include. Quoting and wildcards are
60 include /path/to/included/file/squid.acl.config
62 Includes can be nested up to a hard-coded depth of 16 levels.
63 This arbitrary restriction is to prevent recursive include references
64 from causing Squid entering an infinite loop whilst trying to load
67 Values with byte units
69 Squid accepts size units on some size related directives. All
70 such directives are documented with a default value displaying
73 Units accepted by Squid are:
75 KB - Kilobyte (1024 bytes)
79 Values with spaces, quotes, and other special characters
81 Squid supports directive parameters with spaces, quotes, and other
82 special characters. Surround such parameters with "double quotes". Use
83 the configuration_includes_quoted_values directive to enable or
86 Squid supports reading configuration option parameters from external
87 files using the syntax:
88 parameters("/path/filename")
90 acl whitelist dstdomain parameters("/etc/squid/whitelist.txt")
92 Conditional configuration
94 If-statements can be used to make configuration directives
98 ... regular configuration directives ...
100 ... regular configuration directives ...]
103 The else part is optional. The keywords "if", "else", and "endif"
104 must be typed on their own lines, as if they were regular
105 configuration directives.
107 NOTE: An else-if condition is not supported.
109 These individual conditions types are supported:
112 Always evaluates to true.
114 Always evaluates to false.
115 <integer> = <integer>
116 Equality comparison of two integer numbers.
121 The following SMP-related preprocessor macros can be used.
123 ${process_name} expands to the current Squid process "name"
124 (e.g., squid1, squid2, or cache1).
126 ${process_number} expands to the current Squid process
127 identifier, which is an integer number (e.g., 1, 2, 3) unique
128 across all Squid processes of the current service instance.
130 ${service_name} expands into the current Squid service instance
131 name identifier which is provided by -n on the command line.
135 # options still not yet ported from 2.7 to 3.x
136 NAME: broken_vary_encoding
139 This option is not yet supported by Squid-3.
145 This option is not yet supported by Squid-3.
151 This option is not yet supported by Squid-3.
154 NAME: external_refresh_check
157 This option is not yet supported by Squid-3.
160 NAME: location_rewrite_program location_rewrite_access location_rewrite_children location_rewrite_concurrency
163 This option is not yet supported by Squid-3.
166 NAME: refresh_stale_hit
169 This option is not yet supported by Squid-3.
172 # Options Removed in 3.3
173 NAME: ignore_ims_on_miss
176 Remove this line. The HTTP/1.1 feature is now configured by 'cache_miss_revalidate'.
179 # Options Removed in 3.2
180 NAME: ignore_expect_100
183 Remove this line. The HTTP/1.1 feature is now fully supported by default.
186 NAME: dns_v4_fallback
189 Remove this line. Squid performs a 'Happy Eyeballs' algorithm, the 'fallback' algorithm is no longer relevant.
195 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
198 NAME: maximum_single_addr_tries
201 Replaced by connect_retries. The behaviour has changed, please read the documentation before altering.
207 Remove this line. The feature is supported by default in storage types where update is implemented.
210 NAME: url_rewrite_concurrency
213 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
216 # Options Removed in 3.1
220 Remove this line. DNS is no longer tested on startup.
223 NAME: extension_methods
226 Remove this line. All valid methods for HTTP are accepted by default.
229 # 2.7 Options Removed/Replaced in 3.2
234 # 2.7 Options Removed/Replaced in 3.1
242 Remove this line. HTTP/1.1 is supported by default.
245 NAME: upgrade_http0.9
248 Remove this line. ICY/1.0 streaming protocol is supported by default.
251 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
254 Alter these entries. Use the qos_flows directive instead.
257 # Options Removed in 3.0
261 Since squid-3.0 replace with request_header_access or reply_header_access
262 depending on whether you wish to match client requests or server replies.
265 NAME: httpd_accel_no_pmtu_disc
268 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
271 NAME: wais_relay_host
274 Replace this line with 'cache_peer' configuration.
277 NAME: wais_relay_port
280 Replace this line with 'cache_peer' configuration.
284 OPTIONS FOR AUTHENTICATION
285 -----------------------------------------------------------------------------
294 This is used to define parameters for the various authentication
295 schemes supported by Squid.
297 format: auth_param scheme parameter [setting]
299 The order in which authentication schemes are presented to the client is
300 dependent on the order the scheme first appears in config file. IE
301 has a bug (it's not RFC 2617 compliant) in that it will use the basic
302 scheme if basic is the first entry presented, even if more secure
303 schemes are presented. For now use the order in the recommended
304 settings section below. If other browsers have difficulties (don't
305 recognize the schemes offered even if you are using basic) either
306 put basic first, or disable the other schemes (by commenting out their
309 Once an authentication scheme is fully configured, it can only be
310 shutdown by shutting squid down and restarting. Changes can be made on
311 the fly and activated with a reconfigure. I.E. You can change to a
312 different helper, but not unconfigure the helper completely.
314 Please note that while this directive defines how Squid processes
315 authentication it does not automatically activate authentication.
316 To use authentication you must in addition make use of ACLs based
317 on login name in http_access (proxy_auth, proxy_auth_regex or
318 external with %LOGIN used in the format tag). The browser will be
319 challenged for authentication on the first such acl encountered
320 in http_access processing and will also be re-challenged for new
321 login credentials if the request is being denied by a proxy_auth
324 WARNING: authentication can't be used in a transparently intercepting
325 proxy as the client then thinks it is talking to an origin server and
326 not the proxy. This is a limitation of bending the TCP/IP protocol to
327 transparently intercepting port 80, not a limitation in Squid.
328 Ports flagged 'transparent', 'intercept', or 'tproxy' have
329 authentication disabled.
331 === Parameters common to all schemes. ===
334 Specifies the command for the external authenticator.
336 By default, each authentication scheme is not used unless a
337 program is specified.
339 See http://wiki.squid-cache.org/Features/AddonHelpers for
340 more details on helper operations and creating your own.
343 Specifies a string to be append to request line format for
344 the authentication helper. "Quoted" format values may contain
345 spaces and logformat %macros. In theory, any logformat %macro
346 can be used. In practice, a %macro expands as a dash (-) if
347 the helper request is sent before the required macro
348 information is available to Squid.
350 By default, Squid uses request formats provided in
351 scheme-specific examples below (search for %credentials).
353 The expanded key_extras value is added to the Squid credentials
354 cache and, hence, will affect authentication. It can be used to
355 autenticate different users with identical user names (e.g.,
356 when user authentication depends on http_port).
358 Avoid adding frequently changing information to key_extras. For
359 example, if you add user source IP, and it changes frequently
360 in your environment, then max_user_ip ACL is going to treat
361 every user+IP combination as a unique "user", breaking the ACL
362 and wasting a lot of memory on those user records. It will also
363 force users to authenticate from scratch whenever their IP
367 Specifies the protection scope (aka realm name) which is to be
368 reported to the client for the authentication scheme. It is
369 commonly part of the text the user will see when prompted for
370 their username and password.
372 For Basic the default is "Squid proxy-caching web server".
373 For Digest there is no default, this parameter is mandatory.
374 For NTLM and Negotiate this parameter is ignored.
376 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
378 The maximum number of authenticator processes to spawn. If
379 you start too few Squid will have to wait for them to process
380 a backlog of credential verifications, slowing it down. When
381 password verifications are done via a (slow) network you are
382 likely to need lots of authenticator processes.
384 The startup= and idle= options permit some skew in the exact
385 amount run. A minimum of startup=N will begin during startup
386 and reconfigure. Squid will start more in groups of up to
387 idle=N in an attempt to meet traffic needs and to keep idle=N
388 free above those traffic needs up to the maximum.
390 The concurrency= option sets the number of concurrent requests
391 the helper can process. The default of 0 is used for helpers
392 who only supports one request at a time. Setting this to a
393 number greater than 0 changes the protocol used to include a
394 channel ID field first on the request/response line, allowing
395 multiple requests to be sent to the same helper in parallel
396 without waiting for the response.
398 Concurrency must not be set unless it's known the helper
399 supports the input format with channel-ID fields.
401 NOTE: NTLM and Negotiate schemes do not support concurrency
402 in the Squid code module even though some helpers can.
405 IF HAVE_AUTH_MODULE_BASIC
406 === Basic authentication parameters ===
409 HTTP uses iso-latin-1 as character set, while some
410 authentication backends such as LDAP expects UTF-8. If this is
411 set to on Squid will translate the HTTP iso-latin-1 charset to
412 UTF-8 before sending the username and password to the helper.
414 "credentialsttl" timetolive
415 Specifies how long squid assumes an externally validated
416 username:password pair is valid for - in other words how
417 often the helper program is called for that user. Set this
418 low to force revalidation with short lived passwords.
420 NOTE: setting this high does not impact your susceptibility
421 to replay attacks unless you are using an one-time password
422 system (such as SecureID). If you are using such a system,
423 you will be vulnerable to replay attacks unless you also
424 use the max_user_ip ACL in an http_access rule.
426 "casesensitive" on|off
427 Specifies if usernames are case sensitive. Most user databases
428 are case insensitive allowing the same username to be spelled
429 using both lower and upper case letters, but some are case
430 sensitive. This makes a big difference for user_max_ip ACL
431 processing and similar.
434 IF HAVE_AUTH_MODULE_DIGEST
435 === Digest authentication parameters ===
438 HTTP uses iso-latin-1 as character set, while some
439 authentication backends such as LDAP expects UTF-8. If this is
440 set to on Squid will translate the HTTP iso-latin-1 charset to
441 UTF-8 before sending the username and password to the helper.
443 "nonce_garbage_interval" timeinterval
444 Specifies the interval that nonces that have been issued
445 to client_agent's are checked for validity.
447 "nonce_max_duration" timeinterval
448 Specifies the maximum length of time a given nonce will be
451 "nonce_max_count" number
452 Specifies the maximum number of times a given nonce can be
455 "nonce_strictness" on|off
456 Determines if squid requires strict increment-by-1 behavior
457 for nonce counts, or just incrementing (off - for use when
458 user agents generate nonce counts that occasionally miss 1
459 (ie, 1,2,4,6)). Default off.
461 "check_nonce_count" on|off
462 This directive if set to off can disable the nonce count check
463 completely to work around buggy digest qop implementations in
464 certain mainstream browser versions. Default on to check the
465 nonce count to protect from authentication replay attacks.
467 "post_workaround" on|off
468 This is a workaround to certain buggy browsers who send an
469 incorrect request digest in POST requests when reusing the
470 same nonce as acquired earlier on a GET request.
473 IF HAVE_AUTH_MODULE_NEGOTIATE
474 === Negotiate authentication parameters ===
477 If you experience problems with PUT/POST requests when using
478 the this authentication scheme then you can try setting this
479 to off. This will cause Squid to forcibly close the connection
480 on the initial request where the browser asks which schemes
481 are supported by the proxy.
484 IF HAVE_AUTH_MODULE_NTLM
485 === NTLM authentication parameters ===
488 If you experience problems with PUT/POST requests when using
489 the this authentication scheme then you can try setting this
490 to off. This will cause Squid to forcibly close the connection
491 on the initial request where the browser asks which schemes
492 are supported by the proxy.
495 === Example Configuration ===
497 This configuration displays the recommended authentication scheme
498 order from most to least secure with recommended minimum configuration
499 settings for each scheme:
501 #auth_param negotiate program <uncomment and complete this line to activate>
502 #auth_param negotiate children 20 startup=0 idle=1
503 #auth_param negotiate keep_alive on
505 #auth_param digest program <uncomment and complete this line to activate>
506 #auth_param digest children 20 startup=0 idle=1
507 #auth_param digest realm Squid proxy-caching web server
508 #auth_param digest nonce_garbage_interval 5 minutes
509 #auth_param digest nonce_max_duration 30 minutes
510 #auth_param digest nonce_max_count 50
512 #auth_param ntlm program <uncomment and complete this line to activate>
513 #auth_param ntlm children 20 startup=0 idle=1
514 #auth_param ntlm keep_alive on
516 #auth_param basic program <uncomment and complete this line>
517 #auth_param basic children 5 startup=5 idle=1
518 #auth_param basic realm Squid proxy-caching web server
519 #auth_param basic credentialsttl 2 hours
522 NAME: authenticate_cache_garbage_interval
525 LOC: Config.authenticateGCInterval
527 The time period between garbage collection across the username cache.
528 This is a trade-off between memory utilization (long intervals - say
529 2 days) and CPU (short intervals - say 1 minute). Only change if you
533 NAME: authenticate_ttl
536 LOC: Config.authenticateTTL
538 The time a user & their credentials stay in the logged in
539 user cache since their last request. When the garbage
540 interval passes, all user credentials that have passed their
541 TTL are removed from memory.
544 NAME: authenticate_ip_ttl
546 LOC: Config.authenticateIpTTL
549 If you use proxy authentication and the 'max_user_ip' ACL,
550 this directive controls how long Squid remembers the IP
551 addresses associated with each user. Use a small value
552 (e.g., 60 seconds) if your users might change addresses
553 quickly, as is the case with dialup. You might be safe
554 using a larger value (e.g., 2 hours) in a corporate LAN
555 environment with relatively static address assignments.
560 -----------------------------------------------------------------------------
563 NAME: external_acl_type
564 TYPE: externalAclHelper
565 LOC: Config.externalAclHelperList
568 This option defines external acl classes using a helper program
569 to look up the status
571 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
575 ttl=n TTL in seconds for cached results (defaults to 3600
578 TTL for cached negative lookups (default same
581 Maximum number of acl helper processes spawned to service
582 external acl lookups of this type. (default 20)
584 Minimum number of acl helper processes to spawn during
585 startup and reconfigure to service external acl lookups
586 of this type. (default 0)
588 Number of acl helper processes to keep ahead of traffic
589 loads. Squid will spawn this many at once whenever load
590 rises above the capabilities of existing processes.
591 Up to the value of children-max. (default 1)
592 concurrency=n concurrency level per process. Only used with helpers
593 capable of processing more than one query at a time.
594 cache=n limit the result cache size, default is 262144.
595 grace=n Percentage remaining of TTL where a refresh of a
596 cached entry should be initiated without needing to
597 wait for a new reply. (default is for no grace period)
598 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
599 ipv4 / ipv6 IP protocol used to communicate with this helper.
600 The default is to auto-detect IPv6 and use it when available.
602 FORMAT specifications
604 %LOGIN Authenticated user login name
605 %EXT_USER Username from previous external acl
606 %EXT_LOG Log details from previous external acl
607 %EXT_TAG Tag from previous external acl
608 %IDENT Ident user name
610 %SRCPORT Client source port
613 %PROTO Requested URL scheme
615 %PATH Requested URL path
616 %METHOD Request method
617 %MYADDR Squid interface address
618 %MYPORT Squid http_port number
619 %PATH Requested URL-path (including query-string if any)
620 %USER_CERT SSL User certificate in PEM format
621 %USER_CERTCHAIN SSL User certificate chain in PEM format
622 %USER_CERT_xx SSL User certificate subject attribute xx
623 %USER_CA_CERT_xx SSL User certificate issuer attribute xx
625 %>{Header} HTTP request header "Header"
627 HTTP request header "Hdr" list member "member"
629 HTTP request header list member using ; as
630 list separator. ; can be any non-alphanumeric
633 %<{Header} HTTP reply header "Header"
635 HTTP reply header "Hdr" list member "member"
637 HTTP reply header list member using ; as
638 list separator. ; can be any non-alphanumeric
641 %ACL The name of the ACL being tested.
642 %DATA The ACL arguments. If not used then any arguments
643 is automatically added at the end of the line
645 NOTE: this will encode the arguments as one token,
646 whereas the default will pass each separately.
648 %% The percent sign. Useful for helpers which need
649 an unchanging input format.
652 General request syntax:
654 [channel-ID] FORMAT-values [acl-values ...]
657 FORMAT-values consists of transaction details expanded with
658 whitespace separation per the config file FORMAT specification
659 using the FORMAT macros listed above.
661 acl-values consists of any string specified in the referencing
662 config 'acl ... external' line. see the "acl external" directive.
664 Request values sent to the helper are URL escaped to protect
665 each value in requests against whitespaces.
667 If using protocol=2.5 then the request sent to the helper is not
668 URL escaped to protect against whitespace.
670 NOTE: protocol=3.0 is deprecated as no longer necessary.
672 When using the concurrency= option the protocol is changed by
673 introducing a query channel tag in front of the request/response.
674 The query channel tag is a number between 0 and concurrency-1.
675 This value must be echoed back unchanged to Squid as the first part
676 of the response relating to its request.
679 The helper receives lines expanded per the above format specification
680 and for each input line returns 1 line starting with OK/ERR/BH result
681 code and optionally followed by additional keywords with more details.
684 General result syntax:
686 [channel-ID] result keyword=value ...
688 Result consists of one of the codes:
691 the ACL test produced a match.
694 the ACL test does not produce a match.
697 An internal error occurred in the helper, preventing
698 a result being identified.
700 The meaning of 'a match' is determined by your squid.conf
701 access control configuration. See the Squid wiki for details.
705 user= The users name (login)
707 password= The users password (for login= cache_peer option)
709 message= Message describing the reason for this response.
710 Available as %o in error pages.
711 Useful on (ERR and BH results).
713 tag= Apply a tag to a request. Only sets a tag once,
714 does not alter existing tags.
716 log= String to be logged in access.log. Available as
717 %ea in logformat specifications.
719 clt_conn_tag= Associates a TAG with the client TCP connection.
720 Please see url_rewrite_program related documentation for
723 Any keywords may be sent on any response whether OK, ERR or BH.
725 All response keyword values need to be a single token with URL
726 escaping, or enclosed in double quotes (") and escaped using \ on
727 any double quotes or \ characters within the value. The wrapping
728 double quotes are removed before the value is interpreted by Squid.
729 \r and \n are also replace by CR and LF.
731 Some example key values:
735 user="J. \"Bob\" Smith"
742 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
743 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
744 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
745 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
746 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
749 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
750 DEFAULT: localhost src 127.0.0.1/32 ::1
751 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
752 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
754 Defining an Access List
756 Every access list definition must begin with an aclname and acltype,
757 followed by either type-specific arguments or a quoted filename that
760 acl aclname acltype argument ...
761 acl aclname acltype "file" ...
763 When using "file", the file should contain one item per line.
765 Some acl types supports options which changes their default behaviour.
766 The available options are:
768 -i,+i By default, regular expressions are CASE-SENSITIVE. To make them
769 case-insensitive, use the -i option. To return case-sensitive
770 use the +i option between patterns, or make a new ACL line
773 -n Disable lookups and address type conversions. If lookup or
774 conversion is required because the parameter type (IP or
775 domain name) does not match the message address type (domain
776 name or IP), then the ACL would immediately declare a mismatch
777 without any warnings or lookups.
779 -- Used to stop processing all options, in the case the first acl
780 value has '-' character as first character (for example the '-'
781 is a valid domain name)
783 Some acl types require suspending the current request in order
784 to access some external data source.
785 Those which do are marked with the tag [slow], those which
786 don't are marked as [fast].
787 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
788 for further information
790 ***** ACL TYPES AVAILABLE *****
792 acl aclname src ip-address/mask ... # clients IP address [fast]
793 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
794 acl aclname dst [-n] ip-address/mask ... # URL host's IP address [slow]
795 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
797 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
798 # The arp ACL requires the special configure option --enable-arp-acl.
799 # Furthermore, the ARP ACL code is not portable to all operating systems.
800 # It works on Linux, Solaris, Windows, FreeBSD, and some
801 # other *BSD variants.
804 # NOTE: Squid can only determine the MAC address for clients that are on
805 # the same subnet. If the client is on a different subnet,
806 # then Squid cannot find out its MAC address.
808 acl aclname srcdomain .foo.com ...
809 # reverse lookup, from client IP [slow]
810 acl aclname dstdomain [-n] .foo.com ...
811 # Destination server from URL [fast]
812 acl aclname srcdom_regex [-i] \.foo\.com ...
813 # regex matching client name [slow]
814 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
815 # regex matching server [fast]
817 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
818 # based URL is used and no match is found. The name "none" is used
819 # if the reverse lookup fails.
821 acl aclname src_as number ...
822 acl aclname dst_as number ...
824 # Except for access control, AS numbers can be used for
825 # routing of requests to specific caches. Here's an
826 # example for routing all requests for AS#1241 and only
827 # those to mycache.mydomain.net:
828 # acl asexample dst_as 1241
829 # cache_peer_access mycache.mydomain.net allow asexample
830 # cache_peer_access mycache_mydomain.net deny all
832 acl aclname peername myPeer ...
834 # match against a named cache_peer entry
835 # set unique name= on cache_peer lines for reliable use.
837 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
847 # h1:m1 must be less than h2:m2
849 acl aclname url_regex [-i] ^http:// ...
850 # regex matching on whole URL [fast]
851 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
852 # regex matching on URL login field
853 acl aclname urlpath_regex [-i] \.gif$ ...
854 # regex matching on URL path [fast]
856 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
858 acl aclname localport 3128 ... # TCP port the client connected to [fast]
859 # NP: for interception mode this is usually '80'
861 acl aclname myportname 3128 ... # http(s)_port name [fast]
863 acl aclname proto HTTP FTP ... # request protocol [fast]
865 acl aclname method GET POST ... # HTTP request method [fast]
867 acl aclname http_status 200 301 500- 400-403 ...
868 # status code in reply [fast]
870 acl aclname browser [-i] regexp ...
871 # pattern match on User-Agent header (see also req_header below) [fast]
873 acl aclname referer_regex [-i] regexp ...
874 # pattern match on Referer header [fast]
875 # Referer is highly unreliable, so use with care
877 acl aclname ident username ...
878 acl aclname ident_regex [-i] pattern ...
879 # string match on ident output [slow]
880 # use REQUIRED to accept any non-null ident.
882 acl aclname proxy_auth [-i] username ...
883 acl aclname proxy_auth_regex [-i] pattern ...
884 # perform http authentication challenge to the client and match against
885 # supplied credentials [slow]
887 # takes a list of allowed usernames.
888 # use REQUIRED to accept any valid username.
890 # Will use proxy authentication in forward-proxy scenarios, and plain
891 # http authenticaiton in reverse-proxy scenarios
893 # NOTE: when a Proxy-Authentication header is sent but it is not
894 # needed during ACL checking the username is NOT logged
897 # NOTE: proxy_auth requires a EXTERNAL authentication program
898 # to check username/password combinations (see
899 # auth_param directive).
901 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
902 # as the browser needs to be configured for using a proxy in order
903 # to respond to proxy authentication.
905 acl aclname snmp_community string ...
906 # A community string to limit access to your SNMP Agent [fast]
909 # acl snmppublic snmp_community public
911 acl aclname maxconn number
912 # This will be matched when the client's IP address has
913 # more than <number> TCP connections established. [fast]
914 # NOTE: This only measures direct TCP links so X-Forwarded-For
915 # indirect clients are not counted.
917 acl aclname max_user_ip [-s] number
918 # This will be matched when the user attempts to log in from more
919 # than <number> different ip addresses. The authenticate_ip_ttl
920 # parameter controls the timeout on the ip entries. [fast]
921 # If -s is specified the limit is strict, denying browsing
922 # from any further IP addresses until the ttl has expired. Without
923 # -s Squid will just annoy the user by "randomly" denying requests.
924 # (the counter is reset each time the limit is reached and a
926 # NOTE: in acceleration mode or where there is mesh of child proxies,
927 # clients may appear to come from multiple addresses if they are
928 # going through proxy farms, so a limit of 1 may cause user problems.
930 acl aclname random probability
931 # Pseudo-randomly match requests. Based on the probability given.
932 # Probability may be written as a decimal (0.333), fraction (1/3)
933 # or ratio of matches:non-matches (3:5).
935 acl aclname req_mime_type [-i] mime-type ...
936 # regex match against the mime type of the request generated
937 # by the client. Can be used to detect file upload or some
938 # types HTTP tunneling requests [fast]
939 # NOTE: This does NOT match the reply. You cannot use this
940 # to match the returned file type.
942 acl aclname req_header header-name [-i] any\.regex\.here
943 # regex match against any of the known request headers. May be
944 # thought of as a superset of "browser", "referer" and "mime-type"
947 acl aclname rep_mime_type [-i] mime-type ...
948 # regex match against the mime type of the reply received by
949 # squid. Can be used to detect file download or some
950 # types HTTP tunneling requests. [fast]
951 # NOTE: This has no effect in http_access rules. It only has
952 # effect in rules that affect the reply data stream such as
955 acl aclname rep_header header-name [-i] any\.regex\.here
956 # regex match against any of the known reply headers. May be
957 # thought of as a superset of "browser", "referer" and "mime-type"
960 acl aclname external class_name [arguments...]
961 # external ACL lookup via a helper class defined by the
962 # external_acl_type directive [slow]
964 acl aclname user_cert attribute values...
965 # match against attributes in a user SSL certificate
966 # attribute is one of DN/C/O/CN/L/ST [fast]
968 acl aclname ca_cert attribute values...
969 # match against attributes a users issuing CA SSL certificate
970 # attribute is one of DN/C/O/CN/L/ST [fast]
972 acl aclname ext_user username ...
973 acl aclname ext_user_regex [-i] pattern ...
974 # string match on username returned by external acl helper [slow]
975 # use REQUIRED to accept any non-null user name.
977 acl aclname tag tagvalue ...
978 # string match on tag returned by external acl helper [fast]
979 # DEPRECATED. Only the first tag will match with this ACL.
980 # Use the 'note' ACL instead for handling multiple tag values.
982 acl aclname hier_code codename ...
983 # string match against squid hierarchy code(s); [fast]
984 # e.g., DIRECT, PARENT_HIT, NONE, etc.
986 # NOTE: This has no effect in http_access rules. It only has
987 # effect in rules that affect the reply data stream such as
990 acl aclname note name [value ...]
991 # match transaction annotation [fast]
992 # Without values, matches any annotation with a given name.
993 # With value(s), matches any annotation with a given name that
994 # also has one of the given values.
995 # Names and values are compared using a string equality test.
996 # Annotation sources include note and adaptation_meta directives
997 # as well as helper and eCAP responses.
999 acl aclname adaptation_service service ...
1000 # Matches the name of any icap_service, ecap_service,
1001 # adaptation_service_set, or adaptation_service_chain that Squid
1002 # has used (or attempted to use) for the master transaction.
1003 # This ACL must be defined after the corresponding adaptation
1004 # service is named in squid.conf. This ACL is usable with
1005 # adaptation_meta because it starts matching immediately after
1006 # the service has been selected for adaptation.
1009 acl aclname ssl_error errorname
1010 # match against SSL certificate validation error [fast]
1012 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1015 # The following can be used as shortcuts for certificate properties:
1016 # [ssl::]certHasExpired: the "not after" field is in the past
1017 # [ssl::]certNotYetValid: the "not before" field is in the future
1018 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1019 # [ssl::]certSelfSigned: The certificate is self signed.
1020 # [ssl::]certDomainMismatch: The certificate CN domain does not
1021 # match the name the name of the host we are connecting to.
1023 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1024 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1025 # predefined ACLs, just like the 'all' ACL.
1027 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1028 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1030 acl aclname server_cert_fingerprint [-sha1] fingerprint
1031 # match against server SSL certificate fingerprint [fast]
1033 # The fingerprint is the digest of the DER encoded version
1034 # of the whole certificate. The user should use the form: XX:XX:...
1035 # Optional argument specifies the digest algorithm to use.
1036 # The SHA1 digest algorithm is the default and is currently
1037 # the only algorithm supported (-sha1).
1039 acl aclname any-of acl1 acl2 ...
1040 # match any one of the acls [fast or slow]
1041 # The first matching ACL stops further ACL evaluation.
1043 # ACLs from multiple any-of lines with the same name are ORed.
1044 # For example, A = (a1 or a2) or (a3 or a4) can be written as
1045 # acl A any-of a1 a2
1046 # acl A any-of a3 a4
1048 # This group ACL is fast if all evaluated ACLs in the group are fast
1049 # and slow otherwise.
1051 acl aclname all-of acl1 acl2 ...
1052 # match all of the acls [fast or slow]
1053 # The first mismatching ACL stops further ACL evaluation.
1055 # ACLs from multiple all-of lines with the same name are ORed.
1056 # For example, B = (b1 and b2) or (b3 and b4) can be written as
1057 # acl B all-of b1 b2
1058 # acl B all-of b3 b4
1060 # This group ACL is fast if all evaluated ACLs in the group are fast
1061 # and slow otherwise.
1064 acl macaddress arp 09:00:2b:23:45:67
1065 acl myexample dst_as 1241
1066 acl password proxy_auth REQUIRED
1067 acl fileupload req_mime_type -i ^multipart/form-data$
1068 acl javascript rep_mime_type -i ^application/x-javascript$
1072 # Recommended minimum configuration:
1075 # Example rule allowing access from your local networks.
1076 # Adapt to list your (internal) IP networks from where browsing
1078 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
1079 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
1080 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
1081 acl localnet src fc00::/7 # RFC 4193 local private network range
1082 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1084 acl SSL_ports port 443
1085 acl Safe_ports port 80 # http
1086 acl Safe_ports port 21 # ftp
1087 acl Safe_ports port 443 # https
1088 acl Safe_ports port 70 # gopher
1089 acl Safe_ports port 210 # wais
1090 acl Safe_ports port 1025-65535 # unregistered ports
1091 acl Safe_ports port 280 # http-mgmt
1092 acl Safe_ports port 488 # gss-http
1093 acl Safe_ports port 591 # filemaker
1094 acl Safe_ports port 777 # multiling http
1095 acl CONNECT method CONNECT
1099 NAME: follow_x_forwarded_for
1101 IFDEF: FOLLOW_X_FORWARDED_FOR
1102 LOC: Config.accessList.followXFF
1103 DEFAULT_IF_NONE: deny all
1104 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1106 Allowing or Denying the X-Forwarded-For header to be followed to
1107 find the original source of a request.
1109 Requests may pass through a chain of several other proxies
1110 before reaching us. The X-Forwarded-For header will contain a
1111 comma-separated list of the IP addresses in the chain, with the
1112 rightmost address being the most recent.
1114 If a request reaches us from a source that is allowed by this
1115 configuration item, then we consult the X-Forwarded-For header
1116 to see where that host received the request from. If the
1117 X-Forwarded-For header contains multiple addresses, we continue
1118 backtracking until we reach an address for which we are not allowed
1119 to follow the X-Forwarded-For header, or until we reach the first
1120 address in the list. For the purpose of ACL used in the
1121 follow_x_forwarded_for directive the src ACL type always matches
1122 the address we are testing and srcdomain matches its rDNS.
1124 The end result of this process is an IP address that we will
1125 refer to as the indirect client address. This address may
1126 be treated as the client address for access control, ICAP, delay
1127 pools and logging, depending on the acl_uses_indirect_client,
1128 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1129 log_uses_indirect_client and tproxy_uses_indirect_client options.
1131 This clause only supports fast acl types.
1132 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1134 SECURITY CONSIDERATIONS:
1136 Any host for which we follow the X-Forwarded-For header
1137 can place incorrect information in the header, and Squid
1138 will use the incorrect information as if it were the
1139 source address of the request. This may enable remote
1140 hosts to bypass any access control restrictions that are
1141 based on the client's source addresses.
1145 acl localhost src 127.0.0.1
1146 acl my_other_proxy srcdomain .proxy.example.com
1147 follow_x_forwarded_for allow localhost
1148 follow_x_forwarded_for allow my_other_proxy
1151 NAME: acl_uses_indirect_client
1154 IFDEF: FOLLOW_X_FORWARDED_FOR
1156 LOC: Config.onoff.acl_uses_indirect_client
1158 Controls whether the indirect client address
1159 (see follow_x_forwarded_for) is used instead of the
1160 direct client address in acl matching.
1162 NOTE: maxconn ACL considers direct TCP links and indirect
1163 clients will always have zero. So no match.
1166 NAME: delay_pool_uses_indirect_client
1169 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1171 LOC: Config.onoff.delay_pool_uses_indirect_client
1173 Controls whether the indirect client address
1174 (see follow_x_forwarded_for) is used instead of the
1175 direct client address in delay pools.
1178 NAME: log_uses_indirect_client
1181 IFDEF: FOLLOW_X_FORWARDED_FOR
1183 LOC: Config.onoff.log_uses_indirect_client
1185 Controls whether the indirect client address
1186 (see follow_x_forwarded_for) is used instead of the
1187 direct client address in the access log.
1190 NAME: tproxy_uses_indirect_client
1193 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1195 LOC: Config.onoff.tproxy_uses_indirect_client
1197 Controls whether the indirect client address
1198 (see follow_x_forwarded_for) is used instead of the
1199 direct client address when spoofing the outgoing client.
1201 This has no effect on requests arriving in non-tproxy
1204 SECURITY WARNING: Usage of this option is dangerous
1205 and should not be used trivially. Correct configuration
1206 of follow_x_forewarded_for with a limited set of trusted
1207 sources is required to prevent abuse of your proxy.
1210 NAME: spoof_client_ip
1212 LOC: Config.accessList.spoof_client_ip
1214 DEFAULT_DOC: Allow spoofing on all TPROXY traffic.
1216 Control client IP address spoofing of TPROXY traffic based on
1217 defined access lists.
1219 spoof_client_ip allow|deny [!]aclname ...
1221 If there are no "spoof_client_ip" lines present, the default
1222 is to "allow" spoofing of any suitable request.
1224 Note that the cache_peer "no-tproxy" option overrides this ACL.
1226 This clause supports fast acl types.
1227 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1232 LOC: Config.accessList.http
1233 DEFAULT_IF_NONE: deny all
1234 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1236 Allowing or Denying access based on defined access lists
1238 Access to the HTTP port:
1239 http_access allow|deny [!]aclname ...
1241 NOTE on default values:
1243 If there are no "access" lines present, the default is to deny
1246 If none of the "access" lines cause a match, the default is the
1247 opposite of the last line in the list. If the last line was
1248 deny, the default is allow. Conversely, if the last line
1249 is allow, the default will be deny. For these reasons, it is a
1250 good idea to have an "deny all" entry at the end of your access
1251 lists to avoid potential confusion.
1253 This clause supports both fast and slow acl types.
1254 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1259 # Recommended minimum Access Permission configuration:
1261 # Deny requests to certain unsafe ports
1262 http_access deny !Safe_ports
1264 # Deny CONNECT to other than secure SSL ports
1265 http_access deny CONNECT !SSL_ports
1267 # Only allow cachemgr access from localhost
1268 http_access allow localhost manager
1269 http_access deny manager
1271 # We strongly recommend the following be uncommented to protect innocent
1272 # web applications running on the proxy server who think the only
1273 # one who can access services on "localhost" is a local user
1274 #http_access deny to_localhost
1277 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1280 # Example rule allowing access from your local networks.
1281 # Adapt localnet in the ACL section to list your (internal) IP networks
1282 # from where browsing should be allowed
1283 http_access allow localnet
1284 http_access allow localhost
1286 # And finally deny all other access to this proxy
1287 http_access deny all
1291 NAME: adapted_http_access http_access2
1293 LOC: Config.accessList.adapted_http
1295 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1297 Allowing or Denying access based on defined access lists
1299 Essentially identical to http_access, but runs after redirectors
1300 and ICAP/eCAP adaptation. Allowing access control based on their
1303 If not set then only http_access is used.
1306 NAME: http_reply_access
1308 LOC: Config.accessList.reply
1310 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1312 Allow replies to client requests. This is complementary to http_access.
1314 http_reply_access allow|deny [!] aclname ...
1316 NOTE: if there are no access lines present, the default is to allow
1319 If none of the access lines cause a match the opposite of the
1320 last line will apply. Thus it is good practice to end the rules
1321 with an "allow all" or "deny all" entry.
1323 This clause supports both fast and slow acl types.
1324 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1329 LOC: Config.accessList.icp
1331 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1333 Allowing or Denying access to the ICP port based on defined
1336 icp_access allow|deny [!]aclname ...
1338 NOTE: The default if no icp_access lines are present is to
1339 deny all traffic. This default may cause problems with peers
1342 This clause only supports fast acl types.
1343 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1345 # Allow ICP queries from local networks only
1346 #icp_access allow localnet
1347 #icp_access deny all
1353 LOC: Config.accessList.htcp
1355 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1357 Allowing or Denying access to the HTCP port based on defined
1360 htcp_access allow|deny [!]aclname ...
1362 See also htcp_clr_access for details on access control for
1363 cache purge (CLR) HTCP messages.
1365 NOTE: The default if no htcp_access lines are present is to
1366 deny all traffic. This default may cause problems with peers
1367 using the htcp option.
1369 This clause only supports fast acl types.
1370 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1372 # Allow HTCP queries from local networks only
1373 #htcp_access allow localnet
1374 #htcp_access deny all
1377 NAME: htcp_clr_access
1380 LOC: Config.accessList.htcp_clr
1382 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1384 Allowing or Denying access to purge content using HTCP based
1385 on defined access lists.
1386 See htcp_access for details on general HTCP access control.
1388 htcp_clr_access allow|deny [!]aclname ...
1390 This clause only supports fast acl types.
1391 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1393 # Allow HTCP CLR requests from trusted peers
1394 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1395 htcp_clr_access allow htcp_clr_peer
1396 htcp_clr_access deny all
1401 LOC: Config.accessList.miss
1403 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1405 Determins whether network access is permitted when satisfying a request.
1408 to force your neighbors to use you as a sibling instead of
1411 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1412 miss_access deny !localclients
1413 miss_access allow all
1415 This means only your local clients are allowed to fetch relayed/MISS
1416 replies from the network and all other clients can only fetch cached
1419 The default for this setting allows all clients who passed the
1420 http_access rules to relay via this proxy.
1422 This clause only supports fast acl types.
1423 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1426 NAME: ident_lookup_access
1430 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1431 LOC: Ident::TheConfig.identLookup
1433 A list of ACL elements which, if matched, cause an ident
1434 (RFC 931) lookup to be performed for this request. For
1435 example, you might choose to always perform ident lookups
1436 for your main multi-user Unix boxes, but not for your Macs
1437 and PCs. By default, ident lookups are not performed for
1440 To enable ident lookups for specific client addresses, you
1441 can follow this example:
1443 acl ident_aware_hosts src 198.168.1.0/24
1444 ident_lookup_access allow ident_aware_hosts
1445 ident_lookup_access deny all
1447 Only src type ACL checks are fully supported. A srcdomain
1448 ACL might work at times, but it will not always provide
1451 This clause only supports fast acl types.
1452 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1455 NAME: reply_body_max_size
1456 COMMENT: size [acl acl...]
1459 DEFAULT_DOC: No limit is applied.
1460 LOC: Config.ReplyBodySize
1462 This option specifies the maximum size of a reply body. It can be
1463 used to prevent users from downloading very large files, such as
1464 MP3's and movies. When the reply headers are received, the
1465 reply_body_max_size lines are processed, and the first line where
1466 all (if any) listed ACLs are true is used as the maximum body size
1469 This size is checked twice. First when we get the reply headers,
1470 we check the content-length value. If the content length value exists
1471 and is larger than the allowed size, the request is denied and the
1472 user receives an error message that says "the request or reply
1473 is too large." If there is no content-length, and the reply
1474 size exceeds this limit, the client's connection is just closed
1475 and they will receive a partial reply.
1477 WARNING: downstream caches probably can not detect a partial reply
1478 if there is no content-length header, so they will cache
1479 partial responses and give them out as hits. You should NOT
1480 use this option if you have downstream caches.
1482 WARNING: A maximum size smaller than the size of squid's error messages
1483 will cause an infinite loop and crash squid. Ensure that the smallest
1484 non-zero value you use is greater that the maximum header size plus
1485 the size of your largest error page.
1487 If you set this parameter none (the default), there will be
1490 Configuration Format is:
1491 reply_body_max_size SIZE UNITS [acl ...]
1493 reply_body_max_size 10 MB
1499 -----------------------------------------------------------------------------
1502 NAME: http_port ascii_port
1507 Usage: port [mode] [options]
1508 hostname:port [mode] [options]
1509 1.2.3.4:port [mode] [options]
1511 The socket addresses where Squid will listen for HTTP client
1512 requests. You may specify multiple socket addresses.
1513 There are three forms: port alone, hostname with port, and
1514 IP address with port. If you specify a hostname or IP
1515 address, Squid binds the socket to that specific
1516 address. Most likely, you do not need to bind to a specific
1517 address, so you can use the port number alone.
1519 If you are running Squid in accelerator mode, you
1520 probably want to listen on port 80 also, or instead.
1522 The -a command line option may be used to specify additional
1523 port(s) where Squid listens for proxy request. Such ports will
1524 be plain proxy ports with no options.
1526 You may specify multiple socket addresses on multiple lines.
1530 intercept Support for IP-Layer interception of
1531 outgoing requests without browser settings.
1532 NP: disables authentication and IPv6 on the port.
1534 tproxy Support Linux TPROXY for spoofing outgoing
1535 connections using the client IP address.
1536 NP: disables authentication and maybe IPv6 on the port.
1538 accel Accelerator / reverse proxy mode
1540 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1541 establish secure connection with the client and with
1542 the server, decrypt HTTPS messages as they pass through
1543 Squid, and treat them as unencrypted HTTP messages,
1544 becoming the man-in-the-middle.
1546 The ssl_bump option is required to fully enable
1547 bumping of CONNECT requests.
1549 Omitting the mode flag causes default forward proxy mode to be used.
1552 Accelerator Mode Options:
1554 defaultsite=domainname
1555 What to use for the Host: header if it is not present
1556 in a request. Determines what site (not origin server)
1557 accelerators should consider the default.
1559 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1561 protocol= Protocol to reconstruct accelerated and intercepted
1562 requests with. Defaults to HTTP/1.1 for http_port and
1563 HTTPS/1.1 for https_port.
1564 When an unsupported value is configured Squid will
1565 produce a FATAL error.
1566 Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
1568 vport Virtual host port support. Using the http_port number
1569 instead of the port passed on Host: headers.
1571 vport=NN Virtual host port support. Using the specified port
1572 number instead of the port passed on Host: headers.
1575 Act as if this Squid is the origin server.
1576 This currently means generate new Date: and Expires:
1577 headers on HIT instead of adding Age:.
1579 ignore-cc Ignore request Cache-Control headers.
1581 WARNING: This option violates HTTP specifications if
1582 used in non-accelerator setups.
1584 allow-direct Allow direct forwarding in accelerator mode. Normally
1585 accelerated requests are denied direct forwarding as if
1586 never_direct was used.
1588 WARNING: this option opens accelerator mode to security
1589 vulnerabilities usually only affecting in interception
1590 mode. Make sure to protect forwarding with suitable
1591 http_access rules when using this.
1594 SSL Bump Mode Options:
1595 In addition to these options ssl-bump requires TLS/SSL options.
1597 generate-host-certificates[=<on|off>]
1598 Dynamically create SSL server certificates for the
1599 destination hosts of bumped CONNECT requests.When
1600 enabled, the cert and key options are used to sign
1601 generated certificates. Otherwise generated
1602 certificate will be selfsigned.
1603 If there is a CA certificate lifetime of the generated
1604 certificate equals lifetime of the CA certificate. If
1605 generated certificate is selfsigned lifetime is three
1607 This option is enabled by default when ssl-bump is used.
1608 See the ssl-bump option above for more information.
1610 dynamic_cert_mem_cache_size=SIZE
1611 Approximate total RAM size spent on cached generated
1612 certificates. If set to zero, caching is disabled. The
1613 default value is 4MB.
1617 cert= Path to SSL certificate (PEM format).
1619 key= Path to SSL private key file (PEM format)
1620 if not specified, the certificate file is
1621 assumed to be a combined certificate and
1624 version= The version of SSL/TLS supported
1625 1 automatic (default)
1632 cipher= Colon separated list of supported ciphers.
1633 NOTE: some ciphers such as EDH ciphers depend on
1634 additional settings. If those settings are
1635 omitted the ciphers may be silently ignored
1636 by the OpenSSL library.
1638 options= Various SSL implementation options. The most important
1640 NO_SSLv2 Disallow the use of SSLv2
1641 NO_SSLv3 Disallow the use of SSLv3
1642 NO_TLSv1 Disallow the use of TLSv1.0
1643 NO_TLSv1_1 Disallow the use of TLSv1.1
1644 NO_TLSv1_2 Disallow the use of TLSv1.2
1645 SINGLE_DH_USE Always create a new key when using
1646 temporary/ephemeral DH key exchanges
1647 ALL Enable various bug workarounds
1648 suggested as "harmless" by OpenSSL
1649 Be warned that this reduces SSL/TLS
1650 strength to some attacks.
1651 See OpenSSL SSL_CTX_set_options documentation for a
1652 complete list of options.
1654 clientca= File containing the list of CAs to use when
1655 requesting a client certificate.
1657 cafile= File containing additional CA certificates to
1658 use when verifying client certificates. If unset
1659 clientca will be used.
1661 capath= Directory containing additional CA certificates
1662 and CRL lists to use when verifying client certificates.
1664 crlfile= File of additional CRL lists to use when verifying
1665 the client certificate, in addition to CRLs stored in
1666 the capath. Implies VERIFY_CRL flag below.
1668 dhparams= File containing DH parameters for temporary/ephemeral
1669 DH key exchanges. See OpenSSL documentation for details
1670 on how to create this file.
1671 WARNING: EDH ciphers will be silently disabled if this
1674 sslflags= Various flags modifying the use of SSL:
1676 Don't request client certificates
1677 immediately, but wait until acl processing
1678 requires a certificate (not yet implemented).
1680 Don't use the default CA lists built in
1683 Don't allow for session reuse. Each connection
1684 will result in a new SSL session.
1686 Verify CRL lists when accepting client
1689 Verify CRL lists for all certificates in the
1690 client certificate chain.
1692 sslcontext= SSL session ID context identifier.
1696 connection-auth[=on|off]
1697 use connection-auth=off to tell Squid to prevent
1698 forwarding Microsoft connection oriented authentication
1699 (NTLM, Negotiate and Kerberos)
1701 disable-pmtu-discovery=
1702 Control Path-MTU discovery usage:
1703 off lets OS decide on what to do (default).
1704 transparent disable PMTU discovery when transparent
1706 always disable always PMTU discovery.
1708 In many setups of transparently intercepting proxies
1709 Path-MTU discovery can not work on traffic towards the
1710 clients. This is the case when the intercepting device
1711 does not fully track connections and fails to forward
1712 ICMP must fragment messages to the cache server. If you
1713 have such setup and experience that certain clients
1714 sporadically hang or never complete requests set
1715 disable-pmtu-discovery option to 'transparent'.
1717 name= Specifies a internal name for the port. Defaults to
1718 the port specification (port or addr:port)
1720 tcpkeepalive[=idle,interval,timeout]
1721 Enable TCP keepalive probes of idle connections.
1722 In seconds; idle is the initial time before TCP starts
1723 probing the connection, interval how often to probe, and
1724 timeout the time before giving up.
1726 If you run Squid on a dual-homed machine with an internal
1727 and an external interface we recommend you to specify the
1728 internal address:port in http_port. This way Squid will only be
1729 visible on the internal address.
1733 # Squid normally listens to port 3128
1734 http_port @DEFAULT_HTTP_PORT@
1744 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1746 The socket address where Squid will listen for client requests made
1747 over TLS or SSL connections. Commonly referred to as HTTPS.
1749 This is most useful for situations where you are running squid in
1750 accelerator mode and you want to do the SSL work at the accelerator level.
1752 You may specify multiple socket addresses on multiple lines,
1753 each with their own SSL certificate and/or options.
1757 accel Accelerator / reverse proxy mode
1759 intercept Support for IP-Layer interception of
1760 outgoing requests without browser settings.
1761 NP: disables authentication and IPv6 on the port.
1763 tproxy Support Linux TPROXY for spoofing outgoing
1764 connections using the client IP address.
1765 NP: disables authentication and maybe IPv6 on the port.
1767 ssl-bump For each intercepted connection allowed by ssl_bump
1768 ACLs, establish a secure connection with the client and with
1769 the server, decrypt HTTPS messages as they pass through
1770 Squid, and treat them as unencrypted HTTP messages,
1771 becoming the man-in-the-middle.
1773 An "ssl_bump server-first" match is required to
1774 fully enable bumping of intercepted SSL connections.
1776 Requires tproxy or intercept.
1778 Omitting the mode flag causes default forward proxy mode to be used.
1781 See http_port for a list of generic options
1786 cert= Path to SSL certificate (PEM format).
1788 key= Path to SSL private key file (PEM format)
1789 if not specified, the certificate file is
1790 assumed to be a combined certificate and
1793 version= The version of SSL/TLS supported
1794 1 automatic (default)
1799 cipher= Colon separated list of supported ciphers.
1801 options= Various SSL engine options. The most important
1803 NO_SSLv2 Disallow the use of SSLv2
1804 NO_SSLv3 Disallow the use of SSLv3
1805 NO_TLSv1 Disallow the use of TLSv1
1806 SINGLE_DH_USE Always create a new key when using
1807 temporary/ephemeral DH key exchanges
1808 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1809 documentation for a complete list of options.
1811 clientca= File containing the list of CAs to use when
1812 requesting a client certificate.
1814 cafile= File containing additional CA certificates to
1815 use when verifying client certificates. If unset
1816 clientca will be used.
1818 capath= Directory containing additional CA certificates
1819 and CRL lists to use when verifying client certificates.
1821 crlfile= File of additional CRL lists to use when verifying
1822 the client certificate, in addition to CRLs stored in
1823 the capath. Implies VERIFY_CRL flag below.
1825 dhparams= File containing DH parameters for temporary/ephemeral
1828 sslflags= Various flags modifying the use of SSL:
1830 Don't request client certificates
1831 immediately, but wait until acl processing
1832 requires a certificate (not yet implemented).
1834 Don't use the default CA lists built in
1837 Don't allow for session reuse. Each connection
1838 will result in a new SSL session.
1840 Verify CRL lists when accepting client
1843 Verify CRL lists for all certificates in the
1844 client certificate chain.
1846 sslcontext= SSL session ID context identifier.
1848 generate-host-certificates[=<on|off>]
1849 Dynamically create SSL server certificates for the
1850 destination hosts of bumped SSL requests.When
1851 enabled, the cert and key options are used to sign
1852 generated certificates. Otherwise generated
1853 certificate will be selfsigned.
1854 If there is CA certificate life time of generated
1855 certificate equals lifetime of CA certificate. If
1856 generated certificate is selfsigned lifetime is three
1858 This option is enabled by default when SslBump is used.
1859 See the sslBump option above for more information.
1861 dynamic_cert_mem_cache_size=SIZE
1862 Approximate total RAM size spent on cached generated
1863 certificates. If set to zero, caching is disabled. The
1864 default value is 4MB.
1866 See http_port for a list of available options.
1869 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1872 LOC: Ip::Qos::TheConfig.tosToServer
1874 Allows you to select a TOS/Diffserv value for packets outgoing
1875 on the server side, based on an ACL.
1877 tcp_outgoing_tos ds-field [!]aclname ...
1879 Example where normal_service_net uses the TOS value 0x00
1880 and good_service_net uses 0x20
1882 acl normal_service_net src 10.0.0.0/24
1883 acl good_service_net src 10.0.1.0/24
1884 tcp_outgoing_tos 0x00 normal_service_net
1885 tcp_outgoing_tos 0x20 good_service_net
1887 TOS/DSCP values really only have local significance - so you should
1888 know what you're specifying. For more information, see RFC2474,
1889 RFC2475, and RFC3260.
1891 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1892 "default" to use whatever default your host has. Note that in
1893 practice often only multiples of 4 is usable as the two rightmost bits
1894 have been redefined for use by ECN (RFC 3168 section 23.1).
1896 Processing proceeds in the order specified, and stops at first fully
1899 Only fast ACLs are supported.
1902 NAME: clientside_tos
1905 LOC: Ip::Qos::TheConfig.tosToClient
1907 Allows you to select a TOS/Diffserv value for packets being transmitted
1908 on the client-side, based on an ACL.
1910 clientside_tos ds-field [!]aclname ...
1912 Example where normal_service_net uses the TOS value 0x00
1913 and good_service_net uses 0x20
1915 acl normal_service_net src 10.0.0.0/24
1916 acl good_service_net src 10.0.1.0/24
1917 clientside_tos 0x00 normal_service_net
1918 clientside_tos 0x20 good_service_net
1920 Note: This feature is incompatible with qos_flows. Any TOS values set here
1921 will be overwritten by TOS values in qos_flows.
1924 NAME: tcp_outgoing_mark
1926 IFDEF: SO_MARK&&USE_LIBCAP
1928 LOC: Ip::Qos::TheConfig.nfmarkToServer
1930 Allows you to apply a Netfilter mark value to outgoing packets
1931 on the server side, based on an ACL.
1933 tcp_outgoing_mark mark-value [!]aclname ...
1935 Example where normal_service_net uses the mark value 0x00
1936 and good_service_net uses 0x20
1938 acl normal_service_net src 10.0.0.0/24
1939 acl good_service_net src 10.0.1.0/24
1940 tcp_outgoing_mark 0x00 normal_service_net
1941 tcp_outgoing_mark 0x20 good_service_net
1943 Only fast ACLs are supported.
1946 NAME: clientside_mark
1948 IFDEF: SO_MARK&&USE_LIBCAP
1950 LOC: Ip::Qos::TheConfig.nfmarkToClient
1952 Allows you to apply a Netfilter mark value to packets being transmitted
1953 on the client-side, based on an ACL.
1955 clientside_mark mark-value [!]aclname ...
1957 Example where normal_service_net uses the mark value 0x00
1958 and good_service_net uses 0x20
1960 acl normal_service_net src 10.0.0.0/24
1961 acl good_service_net src 10.0.1.0/24
1962 clientside_mark 0x00 normal_service_net
1963 clientside_mark 0x20 good_service_net
1965 Note: This feature is incompatible with qos_flows. Any mark values set here
1966 will be overwritten by mark values in qos_flows.
1973 LOC: Ip::Qos::TheConfig
1975 Allows you to select a TOS/DSCP value to mark outgoing
1976 connections to the client, based on where the reply was sourced.
1977 For platforms using netfilter, allows you to set a netfilter mark
1978 value instead of, or in addition to, a TOS value.
1980 By default this functionality is disabled. To enable it with the default
1981 settings simply use "qos_flows mark" or "qos_flows tos". Default
1982 settings will result in the netfilter mark or TOS value being copied
1983 from the upstream connection to the client. Note that it is the connection
1984 CONNMARK value not the packet MARK value that is copied.
1986 It is not currently possible to copy the mark or TOS value from the
1987 client to the upstream connection request.
1989 TOS values really only have local significance - so you should
1990 know what you're specifying. For more information, see RFC2474,
1991 RFC2475, and RFC3260.
1993 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1994 in practice often only multiples of 4 is usable as the two rightmost bits
1995 have been redefined for use by ECN (RFC 3168 section 23.1).
1997 Mark values can be any unsigned 32-bit integer value.
1999 This setting is configured by setting the following values:
2001 tos|mark Whether to set TOS or netfilter mark values
2003 local-hit=0xFF Value to mark local cache hits.
2005 sibling-hit=0xFF Value to mark hits from sibling peers.
2007 parent-hit=0xFF Value to mark hits from parent peers.
2009 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2010 over the preserve-miss feature (see below), unless
2011 mask is specified, in which case only the bits
2012 specified in the mask are written.
2014 The TOS variant of the following features are only possible on Linux
2015 and require your kernel to be patched with the TOS preserving ZPH
2016 patch, available from http://zph.bratcheda.org
2017 No patch is needed to preserve the netfilter mark, which will work
2018 with all variants of netfilter.
2020 disable-preserve-miss
2021 This option disables the preservation of the TOS or netfilter
2022 mark. By default, the existing TOS or netfilter mark value of
2023 the response coming from the remote server will be retained
2024 and masked with miss-mark.
2025 NOTE: in the case of a netfilter mark, the mark must be set on
2026 the connection (using the CONNMARK target) not on the packet
2030 Allows you to mask certain bits in the TOS or mark value
2031 received from the remote server, before copying the value to
2032 the TOS sent towards clients.
2033 Default for tos: 0xFF (TOS from server is not changed).
2034 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2036 All of these features require the --enable-zph-qos compilation flag
2037 (enabled by default). Netfilter marking also requires the
2038 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2039 libcap 2.09+ (--with-libcap).
2043 NAME: tcp_outgoing_address
2046 DEFAULT_DOC: Address selection is performed by the operating system.
2047 LOC: Config.accessList.outgoing_address
2049 Allows you to map requests to different outgoing IP addresses
2050 based on the username or source address of the user making
2053 tcp_outgoing_address ipaddr [[!]aclname] ...
2056 Forwarding clients with dedicated IPs for certain subnets.
2058 acl normal_service_net src 10.0.0.0/24
2059 acl good_service_net src 10.0.2.0/24
2061 tcp_outgoing_address 2001:db8::c001 good_service_net
2062 tcp_outgoing_address 10.1.0.2 good_service_net
2064 tcp_outgoing_address 2001:db8::beef normal_service_net
2065 tcp_outgoing_address 10.1.0.1 normal_service_net
2067 tcp_outgoing_address 2001:db8::1
2068 tcp_outgoing_address 10.1.0.3
2070 Processing proceeds in the order specified, and stops at first fully
2073 Squid will add an implicit IP version test to each line.
2074 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2075 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2078 NOTE: The use of this directive using client dependent ACLs is
2079 incompatible with the use of server side persistent connections. To
2080 ensure correct results it is best to set server_persistent_connections
2081 to off when using this directive in such configurations.
2083 NOTE: The use of this directive to set a local IP on outgoing TCP links
2084 is incompatible with using TPROXY to set client IP out outbound TCP links.
2085 When needing to contact peers use the no-tproxy cache_peer option and the
2086 client_dst_passthru directive re-enable normal forwarding such as this.
2090 NAME: host_verify_strict
2093 LOC: Config.onoff.hostStrictVerify
2095 Regardless of this option setting, when dealing with intercepted
2096 traffic, Squid always verifies that the destination IP address matches
2097 the Host header domain or IP (called 'authority form URL').
2099 This enforcement is performed to satisfy a MUST-level requirement in
2100 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2101 authority of the origin server or gateway given by the original URL".
2104 Squid always responds with an HTTP 409 (Conflict) error
2105 page and logs a security warning if there is no match.
2107 Squid verifies that the destination IP address matches
2108 the Host header for forward-proxy and reverse-proxy traffic
2109 as well. For those traffic types, Squid also enables the
2110 following checks, comparing the corresponding Host header
2111 and Request-URI components:
2113 * The host names (domain or IP) must be identical,
2114 but valueless or missing Host header disables all checks.
2115 For the two host names to match, both must be either IP
2118 * Port numbers must be identical, but if a port is missing
2119 the scheme-default port is assumed.
2122 When set to OFF (the default):
2123 Squid allows suspicious requests to continue but logs a
2124 security warning and blocks caching of the response.
2126 * Forward-proxy traffic is not checked at all.
2128 * Reverse-proxy traffic is not checked at all.
2130 * Intercepted traffic which passes verification is handled
2131 according to client_dst_passthru.
2133 * Intercepted requests which fail verification are sent
2134 to the client original destination instead of DIRECT.
2135 This overrides 'client_dst_passthru off'.
2137 For now suspicious intercepted CONNECT requests are always
2138 responded to with an HTTP 409 (Conflict) error page.
2143 As described in CVE-2009-0801 when the Host: header alone is used
2144 to determine the destination of a request it becomes trivial for
2145 malicious scripts on remote websites to bypass browser same-origin
2146 security policy and sandboxing protections.
2148 The cause of this is that such applets are allowed to perform their
2149 own HTTP stack, in which case the same-origin policy of the browser
2150 sandbox only verifies that the applet tries to contact the same IP
2151 as from where it was loaded at the IP level. The Host: header may
2152 be different from the connected IP and approved origin.
2156 NAME: client_dst_passthru
2159 LOC: Config.onoff.client_dst_passthru
2161 With NAT or TPROXY intercepted traffic Squid may pass the request
2162 directly to the original client destination IP or seek a faster
2163 source using the HTTP Host header.
2165 Using Host to locate alternative servers can provide faster
2166 connectivity with a range of failure recovery options.
2167 But can also lead to connectivity trouble when the client and
2168 server are attempting stateful interactions unaware of the proxy.
2170 This option (on by default) prevents alternative DNS entries being
2171 located to send intercepted traffic DIRECT to an origin server.
2172 The clients original destination IP and port will be used instead.
2174 Regardless of this option setting, when dealing with intercepted
2175 traffic Squid will verify the Host: header and any traffic which
2176 fails Host verification will be treated as if this option were ON.
2178 see host_verify_strict for details on the verification process.
2183 -----------------------------------------------------------------------------
2186 NAME: ssl_unclean_shutdown
2190 LOC: Config.SSL.unclean_shutdown
2192 Some browsers (especially MSIE) bugs out on SSL shutdown
2199 LOC: Config.SSL.ssl_engine
2202 The OpenSSL engine to use. You will need to set this if you
2203 would like to use hardware SSL acceleration for example.
2206 NAME: sslproxy_client_certificate
2209 LOC: Config.ssl_client.cert
2212 Client SSL Certificate to use when proxying https:// URLs
2215 NAME: sslproxy_client_key
2218 LOC: Config.ssl_client.key
2221 Client SSL Key to use when proxying https:// URLs
2224 NAME: sslproxy_version
2227 DEFAULT_DOC: automatic SSL/TLS version negotiation
2228 LOC: Config.ssl_client.version
2231 SSL version level to use when proxying https:// URLs
2233 The versions of SSL/TLS supported:
2235 1 automatic (default)
2243 NAME: sslproxy_options
2246 LOC: Config.ssl_client.options
2249 SSL implementation options to use when proxying https:// URLs
2251 The most important being:
2253 NO_SSLv2 Disallow the use of SSLv2
2254 NO_SSLv3 Disallow the use of SSLv3
2255 NO_TLSv1 Disallow the use of TLSv1.0
2256 NO_TLSv1_1 Disallow the use of TLSv1.1
2257 NO_TLSv1_2 Disallow the use of TLSv1.2
2259 Always create a new key when using temporary/ephemeral
2262 Disable use of RFC5077 session tickets. Some servers
2263 may have problems understanding the TLS extension due
2264 to ambiguous specification in RFC4507.
2265 ALL Enable various bug workarounds suggested as "harmless"
2266 by OpenSSL. Be warned that this may reduce SSL/TLS
2267 strength to some attacks.
2269 See the OpenSSL SSL_CTX_set_options documentation for a
2270 complete list of possible options.
2273 NAME: sslproxy_cipher
2276 LOC: Config.ssl_client.cipher
2279 SSL cipher list to use when proxying https:// URLs
2281 Colon separated list of supported ciphers.
2284 NAME: sslproxy_cafile
2287 LOC: Config.ssl_client.cafile
2290 file containing CA certificates to use when verifying server
2291 certificates while proxying https:// URLs
2294 NAME: sslproxy_capath
2297 LOC: Config.ssl_client.capath
2300 directory containing CA certificates to use when verifying
2301 server certificates while proxying https:// URLs
2304 NAME: sslproxy_session_ttl
2307 LOC: Config.SSL.session_ttl
2310 Sets the timeout value for SSL sessions
2313 NAME: sslproxy_session_cache_size
2316 LOC: Config.SSL.sessionCacheSize
2319 Sets the cache size to use for ssl session
2324 TYPE: sslproxy_ssl_bump
2325 LOC: Config.accessList.ssl_bump
2326 DEFAULT_DOC: Does not bump unless rules are present in squid.conf
2329 This option is consulted when a CONNECT request is received on
2330 an http_port (or a new connection is intercepted at an
2331 https_port), provided that port was configured with an ssl-bump
2332 flag. The subsequent data on the connection is either treated as
2333 HTTPS and decrypted OR tunneled at TCP level without decryption,
2334 depending on the first bumping "mode" which ACLs match.
2336 ssl_bump <mode> [!]acl ...
2338 The following bumping modes are supported:
2341 Allow bumping of the connection. Establish a secure connection
2342 with the client first, then connect to the server. This old mode
2343 does not allow Squid to mimic server SSL certificate and does
2344 not work with intercepted SSL connections.
2347 Allow bumping of the connection. Establish a secure connection
2348 with the server first, then establish a secure connection with
2349 the client, using a mimicked server certificate. Works with both
2350 CONNECT requests and intercepted SSL connections.
2353 Become a TCP tunnel without decoding the connection.
2354 Works with both CONNECT requests and intercepted SSL
2355 connections. This is the default behavior when no
2356 ssl_bump option is given or no ssl_bump ACLs match.
2358 By default, no connections are bumped.
2360 The first matching ssl_bump option wins. If no ACLs match, the
2361 connection is not bumped. Unlike most allow/deny ACL lists, ssl_bump
2362 does not have an implicit "negate the last given option" rule. You
2363 must make that rule explicit if you convert old ssl_bump allow/deny
2364 rules that rely on such an implicit rule.
2366 This clause supports both fast and slow acl types.
2367 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2369 See also: http_port ssl-bump, https_port ssl-bump
2372 # Example: Bump all requests except those originating from
2373 # localhost or those going to example.com.
2375 acl broken_sites dstdomain .example.com
2376 ssl_bump none localhost
2377 ssl_bump none broken_sites
2378 ssl_bump server-first all
2381 NAME: sslproxy_flags
2384 LOC: Config.ssl_client.flags
2387 Various flags modifying the use of SSL while proxying https:// URLs:
2388 DONT_VERIFY_PEER Accept certificates that fail verification.
2389 For refined control, see sslproxy_cert_error.
2390 NO_DEFAULT_CA Don't use the default CA list built in
2394 NAME: sslproxy_cert_error
2397 DEFAULT_DOC: Server certificate errors terminate the transaction.
2398 LOC: Config.ssl_client.cert_error
2401 Use this ACL to bypass server certificate validation errors.
2403 For example, the following lines will bypass all validation errors
2404 when talking to servers for example.com. All other
2405 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2407 acl BrokenButTrustedServers dstdomain example.com
2408 sslproxy_cert_error allow BrokenButTrustedServers
2409 sslproxy_cert_error deny all
2411 This clause only supports fast acl types.
2412 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2413 Using slow acl types may result in server crashes
2415 Without this option, all server certificate validation errors
2416 terminate the transaction to protect Squid and the client.
2418 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2419 but should not happen unless your OpenSSL library is buggy.
2422 Bypassing validation errors is dangerous because an
2423 error usually implies that the server cannot be trusted
2424 and the connection may be insecure.
2426 See also: sslproxy_flags and DONT_VERIFY_PEER.
2429 NAME: sslproxy_cert_sign
2432 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2433 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2434 POSTSCRIPTUM: signTrusted all
2435 TYPE: sslproxy_cert_sign
2436 LOC: Config.ssl_client.cert_sign
2439 sslproxy_cert_sign <signing algorithm> acl ...
2441 The following certificate signing algorithms are supported:
2444 Sign using the configured CA certificate which is usually
2445 placed in and trusted by end-user browsers. This is the
2446 default for trusted origin server certificates.
2449 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2450 This is the default for untrusted origin server certificates
2451 that are not self-signed (see ssl::certUntrusted).
2454 Sign using a self-signed certificate with the right CN to
2455 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2456 browser. This is the default for self-signed origin server
2457 certificates (see ssl::certSelfSigned).
2459 This clause only supports fast acl types.
2461 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2462 signing algorithm to generate the certificate and ignores all
2463 subsequent sslproxy_cert_sign options (the first match wins). If no
2464 acl(s) match, the default signing algorithm is determined by errors
2465 detected when obtaining and validating the origin server certificate.
2467 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2468 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2469 CONNECT request that carries a domain name. In all other cases (CONNECT
2470 to an IP address or an intercepted SSL connection), Squid cannot detect
2471 the domain mismatch at certificate generation time when
2472 bump-server-first is used.
2475 NAME: sslproxy_cert_adapt
2478 TYPE: sslproxy_cert_adapt
2479 LOC: Config.ssl_client.cert_adapt
2482 sslproxy_cert_adapt <adaptation algorithm> acl ...
2484 The following certificate adaptation algorithms are supported:
2487 Sets the "Not After" property to the "Not After" property of
2488 the CA certificate used to sign generated certificates.
2491 Sets the "Not Before" property to the "Not Before" property of
2492 the CA certificate used to sign generated certificates.
2494 setCommonName or setCommonName{CN}
2495 Sets Subject.CN property to the host name specified as a
2496 CN parameter or, if no explicit CN parameter was specified,
2497 extracted from the CONNECT request. It is a misconfiguration
2498 to use setCommonName without an explicit parameter for
2499 intercepted or tproxied SSL connections.
2501 This clause only supports fast acl types.
2503 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2504 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2505 corresponding adaptation algorithm to generate the certificate and
2506 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2507 group (i.e., the first match wins within each algorithm group). If no
2508 acl(s) match, the default mimicking action takes place.
2510 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2511 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2512 CONNECT request that carries a domain name. In all other cases (CONNECT
2513 to an IP address or an intercepted SSL connection), Squid cannot detect
2514 the domain mismatch at certificate generation time when
2515 bump-server-first is used.
2518 NAME: sslpassword_program
2521 LOC: Config.Program.ssl_password
2524 Specify a program used for entering SSL key passphrases
2525 when using encrypted SSL certificate keys. If not specified
2526 keys must either be unencrypted, or Squid started with the -N
2527 option to allow it to query interactively for the passphrase.
2529 The key file name is given as argument to the program allowing
2530 selection of the right password if you have multiple encrypted
2535 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2536 -----------------------------------------------------------------------------
2539 NAME: sslcrtd_program
2542 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2543 LOC: Ssl::TheConfig.ssl_crtd
2545 Specify the location and options of the executable for ssl_crtd process.
2546 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2547 For more information use:
2548 @DEFAULT_SSL_CRTD@ -h
2551 NAME: sslcrtd_children
2552 TYPE: HelperChildConfig
2554 DEFAULT: 32 startup=5 idle=1
2555 LOC: Ssl::TheConfig.ssl_crtdChildren
2557 The maximum number of processes spawn to service ssl server.
2558 The maximum this may be safely set to is 32.
2560 The startup= and idle= options allow some measure of skew in your
2565 Sets the minimum number of processes to spawn when Squid
2566 starts or reconfigures. When set to zero the first request will
2567 cause spawning of the first child process to handle it.
2569 Starting too few children temporary slows Squid under load while it
2570 tries to spawn enough additional processes to cope with traffic.
2574 Sets a minimum of how many processes Squid is to try and keep available
2575 at all times. When traffic begins to rise above what the existing
2576 processes can handle this many more will be spawned up to the maximum
2577 configured. A minimum setting of 1 is required.
2579 You must have at least one ssl_crtd process.
2582 NAME: sslcrtvalidator_program
2586 LOC: Ssl::TheConfig.ssl_crt_validator
2588 Specify the location and options of the executable for ssl_crt_validator
2591 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
2594 ttl=n TTL in seconds for cached results. The default is 60 secs
2595 cache=n limit the result cache size. The default value is 2048
2598 NAME: sslcrtvalidator_children
2599 TYPE: HelperChildConfig
2601 DEFAULT: 32 startup=5 idle=1 concurrency=1
2602 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2604 The maximum number of processes spawn to service SSL server.
2605 The maximum this may be safely set to is 32.
2607 The startup= and idle= options allow some measure of skew in your
2612 Sets the minimum number of processes to spawn when Squid
2613 starts or reconfigures. When set to zero the first request will
2614 cause spawning of the first child process to handle it.
2616 Starting too few children temporary slows Squid under load while it
2617 tries to spawn enough additional processes to cope with traffic.
2621 Sets a minimum of how many processes Squid is to try and keep available
2622 at all times. When traffic begins to rise above what the existing
2623 processes can handle this many more will be spawned up to the maximum
2624 configured. A minimum setting of 1 is required.
2628 The number of requests each certificate validator helper can handle in
2629 parallel. A value of 0 indicates the certficate validator does not
2630 support concurrency. Defaults to 1.
2632 When this directive is set to a value >= 1 then the protocol
2633 used to communicate with the helper is modified to include
2634 a request ID in front of the request/response. The request
2635 ID from the request must be echoed back with the response
2638 You must have at least one ssl_crt_validator process.
2642 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2643 -----------------------------------------------------------------------------
2651 To specify other caches in a hierarchy, use the format:
2653 cache_peer hostname type http-port icp-port [options]
2658 # hostname type port port options
2659 # -------------------- -------- ----- ----- -----------
2660 cache_peer parent.foo.net parent 3128 3130 default
2661 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2662 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2663 cache_peer example.com parent 80 0 default
2664 cache_peer cdn.example.com sibling 3128 0
2666 type: either 'parent', 'sibling', or 'multicast'.
2668 proxy-port: The port number where the peer accept HTTP requests.
2669 For other Squid proxies this is usually 3128
2670 For web servers this is usually 80
2672 icp-port: Used for querying neighbor caches about objects.
2673 Set to 0 if the peer does not support ICP or HTCP.
2674 See ICP and HTCP options below for additional details.
2677 ==== ICP OPTIONS ====
2679 You MUST also set icp_port and icp_access explicitly when using these options.
2680 The defaults will prevent peer traffic using ICP.
2683 no-query Disable ICP queries to this neighbor.
2686 Indicates the named peer is a member of a multicast group.
2687 ICP queries will not be sent directly to the peer, but ICP
2688 replies will be accepted from it.
2690 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2691 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2694 To only send ICP queries to this neighbor infrequently.
2695 This is used to keep the neighbor round trip time updated
2696 and is usually used in conjunction with weighted-round-robin.
2699 ==== HTCP OPTIONS ====
2701 You MUST also set htcp_port and htcp_access explicitly when using these options.
2702 The defaults will prevent peer traffic using HTCP.
2705 htcp Send HTCP, instead of ICP, queries to the neighbor.
2706 You probably also want to set the "icp-port" to 4827
2707 instead of 3130. This directive accepts a comma separated
2708 list of options described below.
2710 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2712 htcp=no-clr Send HTCP to the neighbor but without
2713 sending any CLR requests. This cannot be used with
2716 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2717 This cannot be used with no-clr.
2720 Send HTCP to the neighbor including CLRs but only when
2721 they do not result from PURGE requests.
2724 Forward any HTCP CLR requests this proxy receives to the peer.
2727 ==== PEER SELECTION METHODS ====
2729 The default peer selection method is ICP, with the first responding peer
2730 being used as source. These options can be used for better load balancing.
2733 default This is a parent cache which can be used as a "last-resort"
2734 if a peer cannot be located by any of the peer-selection methods.
2735 If specified more than once, only the first is used.
2737 round-robin Load-Balance parents which should be used in a round-robin
2738 fashion in the absence of any ICP queries.
2739 weight=N can be used to add bias.
2741 weighted-round-robin
2742 Load-Balance parents which should be used in a round-robin
2743 fashion with the frequency of each parent being based on the
2744 round trip time. Closer parents are used more often.
2745 Usually used for background-ping parents.
2746 weight=N can be used to add bias.
2748 carp Load-Balance parents which should be used as a CARP array.
2749 The requests will be distributed among the parents based on the
2750 CARP load balancing hash function based on their weight.
2752 userhash Load-balance parents based on the client proxy_auth or ident username.
2754 sourcehash Load-balance parents based on the client source IP.
2757 To be used only for cache peers of type "multicast".
2758 ALL members of this multicast group have "sibling"
2759 relationship with it, not "parent". This is to a multicast
2760 group when the requested object would be fetched only from
2761 a "parent" cache, anyway. It's useful, e.g., when
2762 configuring a pool of redundant Squid proxies, being
2763 members of the same multicast group.
2766 ==== PEER SELECTION OPTIONS ====
2768 weight=N use to affect the selection of a peer during any weighted
2769 peer-selection mechanisms.
2770 The weight must be an integer; default is 1,
2771 larger weights are favored more.
2772 This option does not affect parent selection if a peering
2773 protocol is not in use.
2775 basetime=N Specify a base amount to be subtracted from round trip
2777 It is subtracted before division by weight in calculating
2778 which parent to fectch from. If the rtt is less than the
2779 base time the rtt is set to a minimal value.
2781 ttl=N Specify a TTL to use when sending multicast ICP queries
2783 Only useful when sending to a multicast group.
2784 Because we don't accept ICP replies from random
2785 hosts, you must configure other group members as
2786 peers with the 'multicast-responder' option.
2788 no-delay To prevent access to this neighbor from influencing the
2791 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2792 enabled) for this host from the specified URL rather
2793 than the Squid default location.
2796 ==== CARP OPTIONS ====
2798 carp-key=key-specification
2799 use a different key than the full URL to hash against the peer.
2800 the key-specification is a comma-separated list of the keywords
2801 scheme, host, port, path, params
2802 Order is not important.
2804 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2806 originserver Causes this parent to be contacted as an origin server.
2807 Meant to be used in accelerator setups when the peer
2811 Set the Host header of requests forwarded to this peer.
2812 Useful in accelerator setups where the server (peer)
2813 expects a certain domain name but clients may request
2814 others. ie example.com or www.example.com
2816 no-digest Disable request of cache digests.
2819 Disables requesting ICMP RTT database (NetDB).
2822 ==== AUTHENTICATION OPTIONS ====
2825 If this is a personal/workgroup proxy and your parent
2826 requires proxy authentication.
2828 Note: The string can include URL escapes (i.e. %20 for
2829 spaces). This also means % must be written as %%.
2832 Send login details received from client to this peer.
2833 Both Proxy- and WWW-Authorization headers are passed
2834 without alteration to the peer.
2835 Authentication is not required by Squid for this to work.
2837 Note: This will pass any form of authentication but
2838 only Basic auth will work through a proxy unless the
2839 connection-auth options are also used.
2841 login=PASS Send login details received from client to this peer.
2842 Authentication is not required by this option.
2844 If there are no client-provided authentication headers
2845 to pass on, but username and password are available
2846 from an external ACL user= and password= result tags
2847 they may be sent instead.
2849 Note: To combine this with proxy_auth both proxies must
2850 share the same user database as HTTP only allows for
2851 a single login (one for proxy, one for origin server).
2852 Also be warned this will expose your users proxy
2853 password to the peer. USE WITH CAUTION
2856 Send the username to the upstream cache, but with a
2857 fixed password. This is meant to be used when the peer
2858 is in another administrative domain, but it is still
2859 needed to identify each user.
2860 The star can optionally be followed by some extra
2861 information which is added to the username. This can
2862 be used to identify this proxy to the peer, similar to
2863 the login=username:password option above.
2866 If this is a personal/workgroup proxy and your parent
2867 requires a secure proxy authentication.
2868 The first principal from the default keytab or defined by
2869 the environment variable KRB5_KTNAME will be used.
2871 WARNING: The connection may transmit requests from multiple
2872 clients. Negotiate often assumes end-to-end authentication
2873 and a single-client. Which is not strictly true here.
2875 login=NEGOTIATE:principal_name
2876 If this is a personal/workgroup proxy and your parent
2877 requires a secure proxy authentication.
2878 The principal principal_name from the default keytab or
2879 defined by the environment variable KRB5_KTNAME will be
2882 WARNING: The connection may transmit requests from multiple
2883 clients. Negotiate often assumes end-to-end authentication
2884 and a single-client. Which is not strictly true here.
2886 connection-auth=on|off
2887 Tell Squid that this peer does or not support Microsoft
2888 connection oriented authentication, and any such
2889 challenges received from there should be ignored.
2890 Default is auto to automatically determine the status
2894 ==== SSL / HTTPS / TLS OPTIONS ====
2896 ssl Encrypt connections to this peer with SSL/TLS.
2898 sslcert=/path/to/ssl/certificate
2899 A client SSL certificate to use when connecting to
2902 sslkey=/path/to/ssl/key
2903 The private SSL key corresponding to sslcert above.
2904 If 'sslkey' is not specified 'sslcert' is assumed to
2905 reference a combined file containing both the
2906 certificate and the key.
2908 sslversion=1|2|3|4|5|6
2909 The SSL version to use when connecting to this peer
2910 1 = automatic (default)
2917 sslcipher=... The list of valid SSL ciphers to use when connecting
2920 ssloptions=... Specify various SSL implementation options:
2922 NO_SSLv2 Disallow the use of SSLv2
2923 NO_SSLv3 Disallow the use of SSLv3
2924 NO_TLSv1 Disallow the use of TLSv1.0
2925 NO_TLSv1_1 Disallow the use of TLSv1.1
2926 NO_TLSv1_2 Disallow the use of TLSv1.2
2928 Always create a new key when using
2929 temporary/ephemeral DH key exchanges
2930 ALL Enable various bug workarounds
2931 suggested as "harmless" by OpenSSL
2932 Be warned that this reduces SSL/TLS
2933 strength to some attacks.
2935 See the OpenSSL SSL_CTX_set_options documentation for a
2938 sslcafile=... A file containing additional CA certificates to use
2939 when verifying the peer certificate.
2941 sslcapath=... A directory containing additional CA certificates to
2942 use when verifying the peer certificate.
2944 sslcrlfile=... A certificate revocation list file to use when
2945 verifying the peer certificate.
2947 sslflags=... Specify various flags modifying the SSL implementation:
2950 Accept certificates even if they fail to
2953 Don't use the default CA list built in
2956 Don't verify the peer certificate
2957 matches the server name
2959 ssldomain= The peer name as advertised in it's certificate.
2960 Used for verifying the correctness of the received peer
2961 certificate. If not specified the peer hostname will be
2965 Enable the "Front-End-Https: On" header needed when
2966 using Squid as a SSL frontend in front of Microsoft OWA.
2967 See MS KB document Q307347 for details on this header.
2968 If set to auto the header will only be added if the
2969 request is forwarded as a https:// URL.
2972 ==== GENERAL OPTIONS ====
2975 A peer-specific connect timeout.
2976 Also see the peer_connect_timeout directive.
2978 connect-fail-limit=N
2979 How many times connecting to a peer must fail before
2980 it is marked as down. Standby connection failures
2981 count towards this limit. Default is 10.
2983 allow-miss Disable Squid's use of only-if-cached when forwarding
2984 requests to siblings. This is primarily useful when
2985 icp_hit_stale is used by the sibling. To extensive use
2986 of this option may result in forwarding loops, and you
2987 should avoid having two-way peerings with this option.
2988 For example to deny peer usage on requests from peer
2989 by denying cache_peer_access if the source is a peer.
2991 max-conn=N Limit the number of concurrent connections the Squid
2992 may open to this peer, including already opened idle
2993 and standby connections. There is no peer-specific
2994 connection limit by default.
2996 A peer exceeding the limit is not used for new
2997 requests unless a standby connection is available.
2999 max-conn currently works poorly with idle persistent
3000 connections: When a peer reaches its max-conn limit,
3001 and there are idle persistent connections to the peer,
3002 the peer may not be selected because the limiting code
3003 does not know whether Squid can reuse those idle
3006 standby=N Maintain a pool of N "hot standby" connections to an
3007 UP peer, available for requests when no idle
3008 persistent connection is available (or safe) to use.
3009 By default and with zero N, no such pool is maintained.
3010 N must not exceed the max-conn limit (if any).
3012 At start or after reconfiguration, Squid opens new TCP
3013 standby connections until there are N connections
3014 available and then replenishes the standby pool as
3015 opened connections are used up for requests. A used
3016 connection never goes back to the standby pool, but
3017 may go to the regular idle persistent connection pool
3018 shared by all peers and origin servers.
3020 Squid never opens multiple new standby connections
3021 concurrently. This one-at-a-time approach minimizes
3022 flooding-like effect on peers. Furthermore, just a few
3023 standby connections should be sufficient in most cases
3024 to supply most new requests with a ready-to-use
3027 Standby connections obey server_idle_pconn_timeout.
3028 For the feature to work as intended, the peer must be
3029 configured to accept and keep them open longer than
3030 the idle timeout at the connecting Squid, to minimize
3031 race conditions typical to idle used persistent
3032 connections. Default request_timeout and
3033 server_idle_pconn_timeout values ensure such a
3036 name=xxx Unique name for the peer.
3037 Required if you have multiple peers on the same host
3038 but different ports.
3039 This name can be used in cache_peer_access and similar
3040 directives to dentify the peer.
3041 Can be used by outgoing access controls through the
3044 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3045 requests to this peer. Use normal address selection instead.
3046 This overrides the spoof_client_ip ACL.
3048 proxy-only objects fetched from the peer will not be stored locally.
3052 NAME: cache_peer_domain cache_host_domain
3057 Use to limit the domains for which a neighbor cache will be
3061 cache_peer_domain cache-host domain [domain ...]
3062 cache_peer_domain cache-host !domain
3064 For example, specifying
3066 cache_peer_domain parent.foo.net .edu
3068 has the effect such that UDP query packets are sent to
3069 'bigserver' only when the requested object exists on a
3070 server in the .edu domain. Prefixing the domainname
3071 with '!' means the cache will be queried for objects
3074 NOTE: * Any number of domains may be given for a cache-host,
3075 either on the same or separate lines.
3076 * When multiple domains are given for a particular
3077 cache-host, the first matched domain is applied.
3078 * Cache hosts with no domain restrictions are queried
3080 * There are no defaults.
3081 * There is also a 'cache_peer_access' tag in the ACL
3085 NAME: cache_peer_access
3090 Similar to 'cache_peer_domain' but provides more flexibility by
3094 cache_peer_access cache-host allow|deny [!]aclname ...
3096 The syntax is identical to 'http_access' and the other lists of
3097 ACL elements. See the comments for 'http_access' below, or
3098 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
3101 NAME: neighbor_type_domain
3102 TYPE: hostdomaintype
3104 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3107 Modify the cache_peer neighbor type when passing requests
3108 about specific domains to the peer.
3111 neighbor_type_domain neighbor parent|sibling domain domain ...
3114 cache_peer foo.example.com parent 3128 3130
3115 neighbor_type_domain foo.example.com sibling .au .de
3117 The above configuration treats all requests to foo.example.com as a
3118 parent proxy unless the request is for a .au or .de ccTLD domain name.
3121 NAME: dead_peer_timeout
3125 LOC: Config.Timeout.deadPeer
3127 This controls how long Squid waits to declare a peer cache
3128 as "dead." If there are no ICP replies received in this
3129 amount of time, Squid will declare the peer dead and not
3130 expect to receive any further ICP replies. However, it
3131 continues to send ICP queries, and will mark the peer as
3132 alive upon receipt of the first subsequent ICP reply.
3134 This timeout also affects when Squid expects to receive ICP
3135 replies from peers. If more than 'dead_peer' seconds have
3136 passed since the last ICP reply was received, Squid will not
3137 expect to receive an ICP reply on the next query. Thus, if
3138 your time between requests is greater than this timeout, you
3139 will see a lot of requests sent DIRECT to origin servers
3140 instead of to your parents.
3143 NAME: forward_max_tries
3146 LOC: Config.forward_max_tries
3148 Controls how many different forward paths Squid will try
3149 before giving up. See also forward_timeout.
3151 NOTE: connect_retries (default: none) can make each of these
3152 possible forwarding paths be tried multiple times.
3155 NAME: hierarchy_stoplist
3158 LOC: Config.hierarchy_stoplist
3160 A list of words which, if found in a URL, cause the object to
3161 be handled directly by this cache. In other words, use this
3162 to not query neighbor caches for certain objects. You may
3163 list this option multiple times.
3166 hierarchy_stoplist cgi-bin ?
3168 Note: never_direct overrides this option.
3172 MEMORY CACHE OPTIONS
3173 -----------------------------------------------------------------------------
3180 LOC: Config.memMaxSize
3182 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3183 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3184 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3185 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3187 'cache_mem' specifies the ideal amount of memory to be used
3189 * In-Transit objects
3191 * Negative-Cached objects
3193 Data for these objects are stored in 4 KB blocks. This
3194 parameter specifies the ideal upper limit on the total size of
3195 4 KB blocks allocated. In-Transit objects take the highest
3198 In-transit objects have priority over the others. When
3199 additional space is needed for incoming data, negative-cached
3200 and hot objects will be released. In other words, the
3201 negative-cached and hot objects will fill up any unused space
3202 not needed for in-transit objects.
3204 If circumstances require, this limit will be exceeded.
3205 Specifically, if your incoming request rate requires more than
3206 'cache_mem' of memory to hold in-transit objects, Squid will
3207 exceed this limit to satisfy the new requests. When the load
3208 decreases, blocks will be freed until the high-water mark is
3209 reached. Thereafter, blocks will be used to store hot
3212 If shared memory caching is enabled, Squid does not use the shared
3213 cache space for in-transit objects, but they still consume as much
3214 local memory as they need. For more details about the shared memory
3215 cache, see memory_cache_shared.
3218 NAME: maximum_object_size_in_memory
3222 LOC: Config.Store.maxInMemObjSize
3224 Objects greater than this size will not be attempted to kept in
3225 the memory cache. This should be set high enough to keep objects
3226 accessed frequently in memory to improve performance whilst low
3227 enough to keep larger objects from hoarding cache_mem.
3230 NAME: memory_cache_shared
3233 LOC: Config.memShared
3235 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3237 Controls whether the memory cache is shared among SMP workers.
3239 The shared memory cache is meant to occupy cache_mem bytes and replace
3240 the non-shared memory cache, although some entities may still be
3241 cached locally by workers for now (e.g., internal and in-transit
3242 objects may be served from a local memory cache even if shared memory
3243 caching is enabled).
3245 By default, the memory cache is shared if and only if all of the
3246 following conditions are satisfied: Squid runs in SMP mode with
3247 multiple workers, cache_mem is positive, and Squid environment
3248 supports required IPC primitives (e.g., POSIX shared memory segments
3249 and GCC-style atomic operations).
3251 To avoid blocking locks, shared memory uses opportunistic algorithms
3252 that do not guarantee that every cachable entity that could have been
3253 shared among SMP workers will actually be shared.
3255 Currently, entities exceeding 32KB in size cannot be shared.
3258 NAME: memory_cache_mode
3262 DEFAULT_DOC: Keep the most recently fetched objects in memory
3264 Controls which objects to keep in the memory cache (cache_mem)
3266 always Keep most recently fetched objects in memory (default)
3268 disk Only disk cache hits are kept in memory, which means
3269 an object must first be cached on disk and then hit
3270 a second time before cached in memory.
3272 network Only objects fetched from network is kept in memory
3275 NAME: memory_replacement_policy
3277 LOC: Config.memPolicy
3280 The memory replacement policy parameter determines which
3281 objects are purged from memory when memory space is needed.
3283 See cache_replacement_policy for details on algorithms.
3288 -----------------------------------------------------------------------------
3291 NAME: cache_replacement_policy
3293 LOC: Config.replPolicy
3296 The cache replacement policy parameter determines which
3297 objects are evicted (replaced) when disk space is needed.
3299 lru : Squid's original list based LRU policy
3300 heap GDSF : Greedy-Dual Size Frequency
3301 heap LFUDA: Least Frequently Used with Dynamic Aging
3302 heap LRU : LRU policy implemented using a heap
3304 Applies to any cache_dir lines listed below this directive.
3306 The LRU policies keeps recently referenced objects.
3308 The heap GDSF policy optimizes object hit rate by keeping smaller
3309 popular objects in cache so it has a better chance of getting a
3310 hit. It achieves a lower byte hit rate than LFUDA though since
3311 it evicts larger (possibly popular) objects.
3313 The heap LFUDA policy keeps popular objects in cache regardless of
3314 their size and thus optimizes byte hit rate at the expense of
3315 hit rate since one large, popular object will prevent many
3316 smaller, slightly less popular objects from being cached.
3318 Both policies utilize a dynamic aging mechanism that prevents
3319 cache pollution that can otherwise occur with frequency-based
3320 replacement policies.
3322 NOTE: if using the LFUDA replacement policy you should increase
3323 the value of maximum_object_size above its default of 4 MB to
3324 to maximize the potential byte hit rate improvement of LFUDA.
3326 For more information about the GDSF and LFUDA cache replacement
3327 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3328 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3331 NAME: minimum_object_size
3335 DEFAULT_DOC: no limit
3336 LOC: Config.Store.minObjectSize
3338 Objects smaller than this size will NOT be saved on disk. The
3339 value is specified in bytes, and the default is 0 KB, which
3340 means all responses can be stored.
3343 NAME: maximum_object_size
3347 LOC: Config.Store.maxObjectSize
3349 Set the default value for max-size parameter on any cache_dir.
3350 The value is specified in bytes, and the default is 4 MB.
3352 If you wish to get a high BYTES hit ratio, you should probably
3353 increase this (one 32 MB object hit counts for 3200 10KB
3356 If you wish to increase hit ratio more than you want to
3357 save bandwidth you should leave this low.
3359 NOTE: if using the LFUDA replacement policy you should increase
3360 this value to maximize the byte hit rate improvement of LFUDA!
3361 See cache_replacement_policy for a discussion of this policy.
3367 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3368 LOC: Config.cacheSwap
3371 cache_dir Type Directory-Name Fs-specific-data [options]
3373 You can specify multiple cache_dir lines to spread the
3374 cache among different disk partitions.
3376 Type specifies the kind of storage system to use. Only "ufs"
3377 is built by default. To enable any of the other storage systems
3378 see the --enable-storeio configure option.
3380 'Directory' is a top-level directory where cache swap
3381 files will be stored. If you want to use an entire disk
3382 for caching, this can be the mount-point directory.
3383 The directory must exist and be writable by the Squid
3384 process. Squid will NOT create this directory for you.
3386 In SMP configurations, cache_dir must not precede the workers option
3387 and should use configuration macros or conditionals to give each
3388 worker interested in disk caching a dedicated cache directory.
3391 ==== The ufs store type ====
3393 "ufs" is the old well-known Squid storage format that has always
3397 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3399 'Mbytes' is the amount of disk space (MB) to use under this
3400 directory. The default is 100 MB. Change this to suit your
3401 configuration. Do NOT put the size of your disk drive here.
3402 Instead, if you want Squid to use the entire disk drive,
3403 subtract 20% and use that value.
3405 'L1' is the number of first-level subdirectories which
3406 will be created under the 'Directory'. The default is 16.
3408 'L2' is the number of second-level subdirectories which
3409 will be created under each first-level directory. The default
3413 ==== The aufs store type ====
3415 "aufs" uses the same storage format as "ufs", utilizing
3416 POSIX-threads to avoid blocking the main Squid process on
3417 disk-I/O. This was formerly known in Squid as async-io.
3420 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3422 see argument descriptions under ufs above
3425 ==== The diskd store type ====
3427 "diskd" uses the same storage format as "ufs", utilizing a
3428 separate process to avoid blocking the main Squid process on
3432 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3434 see argument descriptions under ufs above
3436 Q1 specifies the number of unacknowledged I/O requests when Squid
3437 stops opening new files. If this many messages are in the queues,
3438 Squid won't open new files. Default is 64
3440 Q2 specifies the number of unacknowledged messages when Squid
3441 starts blocking. If this many messages are in the queues,
3442 Squid blocks until it receives some replies. Default is 72
3444 When Q1 < Q2 (the default), the cache directory is optimized
3445 for lower response time at the expense of a decrease in hit
3446 ratio. If Q1 > Q2, the cache directory is optimized for
3447 higher hit ratio at the expense of an increase in response
3451 ==== The rock store type ====
3454 cache_dir rock Directory-Name Mbytes [options]
3456 The Rock Store type is a database-style storage. All cached
3457 entries are stored in a "database" file, using fixed-size slots.
3458 A single entry occupies one or more slots.
3460 If possible, Squid using Rock Store creates a dedicated kid
3461 process called "disker" to avoid blocking Squid worker(s) on disk
3462 I/O. One disker kid is created for each rock cache_dir. Diskers
3463 are created only when Squid, running in daemon mode, has support
3464 for the IpcIo disk I/O module.
3466 swap-timeout=msec: Squid will not start writing a miss to or
3467 reading a hit from disk if it estimates that the swap operation
3468 will take more than the specified number of milliseconds. By
3469 default and when set to zero, disables the disk I/O time limit
3470 enforcement. Ignored when using blocking I/O module because
3471 blocking synchronous I/O does not allow Squid to estimate the
3472 expected swap wait time.
3474 max-swap-rate=swaps/sec: Artificially limits disk access using
3475 the specified I/O rate limit. Swap out requests that
3476 would cause the average I/O rate to exceed the limit are
3477 delayed. Individual swap in requests (i.e., hits or reads) are
3478 not delayed, but they do contribute to measured swap rate and
3479 since they are placed in the same FIFO queue as swap out
3480 requests, they may wait longer if max-swap-rate is smaller.
3481 This is necessary on file systems that buffer "too
3482 many" writes and then start blocking Squid and other processes
3483 while committing those writes to disk. Usually used together
3484 with swap-timeout to avoid excessive delays and queue overflows
3485 when disk demand exceeds available disk "bandwidth". By default
3486 and when set to zero, disables the disk I/O rate limit
3487 enforcement. Currently supported by IpcIo module only.
3489 slot-size=bytes: The size of a database "record" used for
3490 storing cached responses. A cached response occupies at least
3491 one slot and all database I/O is done using individual slots so
3492 increasing this parameter leads to more disk space waste while
3493 decreasing it leads to more disk I/O overheads. Should be a
3494 multiple of your operating system I/O page size. Defaults to
3495 16KBytes. A housekeeping header is stored with each slot and
3496 smaller slot-sizes will be rejected. The header is smaller than
3500 ==== COMMON OPTIONS ====
3502 no-store no new objects should be stored to this cache_dir.
3504 min-size=n the minimum object size in bytes this cache_dir
3505 will accept. It's used to restrict a cache_dir
3506 to only store large objects (e.g. AUFS) while
3507 other stores are optimized for smaller objects
3511 max-size=n the maximum object size in bytes this cache_dir
3513 The value in maximum_object_size directive sets
3514 the default unless more specific details are
3515 available (ie a small store capacity).
3517 Note: To make optimal use of the max-size limits you should order
3518 the cache_dir lines with the smallest max-size value first.
3522 # Uncomment and adjust the following to add a disk cache directory.
3523 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3527 NAME: store_dir_select_algorithm
3529 LOC: Config.store_dir_select_algorithm
3532 How Squid selects which cache_dir to use when the response
3533 object will fit into more than one.
3535 Regardless of which algorithm is used the cache_dir min-size
3536 and max-size parameters are obeyed. As such they can affect
3537 the selection algorithm by limiting the set of considered
3544 This algorithm is suited to caches with similar cache_dir
3545 sizes and disk speeds.
3547 The disk with the least I/O pending is selected.
3548 When there are multiple disks with the same I/O load ranking
3549 the cache_dir with most available capacity is selected.
3551 When a mix of cache_dir sizes are configured the faster disks
3552 have a naturally lower I/O loading and larger disks have more
3553 capacity. So space used to store objects and data throughput
3554 may be very unbalanced towards larger disks.
3559 This algorithm is suited to caches with unequal cache_dir
3562 Each cache_dir is selected in a rotation. The next suitable
3565 Available cache_dir capacity is only considered in relation
3566 to whether the object will fit and meets the min-size and
3567 max-size parameters.
3569 Disk I/O loading is only considered to prevent overload on slow
3570 disks. This algorithm does not spread objects by size, so any
3571 I/O loading per-disk may appear very unbalanced and volatile.
3573 If several cache_dirs use similar min-size, max-size, or other
3574 limits to to reject certain responses, then do not group such
3575 cache_dir lines together, to avoid round-robin selection bias
3576 towards the first cache_dir after the group. Instead, interleave
3577 cache_dir lines from different groups. For example:
3579 store_dir_select_algorithm round-robin
3580 cache_dir rock /hdd1 ... min-size=100000
3581 cache_dir rock /ssd1 ... max-size=99999
3582 cache_dir rock /hdd2 ... min-size=100000
3583 cache_dir rock /ssd2 ... max-size=99999
3584 cache_dir rock /hdd3 ... min-size=100000
3585 cache_dir rock /ssd3 ... max-size=99999
3588 NAME: max_open_disk_fds
3590 LOC: Config.max_open_disk_fds
3592 DEFAULT_DOC: no limit
3594 To avoid having disk as the I/O bottleneck Squid can optionally
3595 bypass the on-disk cache if more than this amount of disk file
3596 descriptors are open.
3598 A value of 0 indicates no limit.
3601 NAME: cache_swap_low
3602 COMMENT: (percent, 0-100)
3605 LOC: Config.Swap.lowWaterMark
3607 The low-water mark for cache object replacement.
3608 Replacement begins when the swap (disk) usage is above the
3609 low-water mark and attempts to maintain utilization near the
3610 low-water mark. As swap utilization gets close to high-water
3611 mark object eviction becomes more aggressive. If utilization is
3612 close to the low-water mark less replacement is done each time.
3614 Defaults are 90% and 95%. If you have a large cache, 5% could be
3615 hundreds of MB. If this is the case you may wish to set these
3616 numbers closer together.
3618 See also cache_swap_high
3621 NAME: cache_swap_high
3622 COMMENT: (percent, 0-100)
3625 LOC: Config.Swap.highWaterMark
3627 The high-water mark for cache object replacement.
3628 Replacement begins when the swap (disk) usage is above the
3629 low-water mark and attempts to maintain utilization near the
3630 low-water mark. As swap utilization gets close to high-water
3631 mark object eviction becomes more aggressive. If utilization is
3632 close to the low-water mark less replacement is done each time.
3634 Defaults are 90% and 95%. If you have a large cache, 5% could be
3635 hundreds of MB. If this is the case you may wish to set these
3636 numbers closer together.
3638 See also cache_swap_low
3643 -----------------------------------------------------------------------------
3650 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
3654 logformat <name> <format specification>
3656 Defines an access log format.
3658 The <format specification> is a string with embedded % format codes
3660 % format codes all follow the same basic structure where all but
3661 the formatcode is optional. Output strings are automatically escaped
3662 as required according to their context and the output format
3663 modifiers are usually not needed, but can be specified if an explicit
3664 output format is desired.
3666 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3668 " output in quoted string format
3669 [ output in squid text log format as used by log_mime_hdrs
3670 # output in URL quoted format
3675 width minimum and/or maximum field width:
3676 [width_min][.width_max]
3677 When minimum starts with 0, the field is zero-padded.
3678 String values exceeding maximum width are truncated.
3680 {arg} argument such as header name etc
3684 % a literal % character
3685 sn Unique sequence number per log line entry
3686 err_code The ID of an error response served by Squid or
3687 a similar internal error identifier.
3688 err_detail Additional err_code-dependent error information.
3689 note The annotation specified by the argument. Also
3690 logs the adaptation meta headers set by the
3691 adaptation_meta configuration parameter.
3692 If no argument given all annotations logged.
3693 The argument may include a separator to use with
3696 By default, multiple note values are separated with ","
3697 and multiple notes are separated with "\r\n".
3698 When logging named notes with %{name}note, the
3699 explicitly configured separator is used between note
3700 values. When logging all notes with %note, the
3701 explicitly configured separator is used between
3702 individual notes. There is currently no way to
3703 specify both value and notes separators when logging
3704 all notes with %note.
3706 Connection related format codes:
3708 >a Client source IP address
3710 >p Client source port
3711 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3712 >la Local IP address the client connected to
3713 >lp Local port number the client connected to
3714 >qos Client connection TOS/DSCP value set by Squid
3715 >nfmark Client connection netfilter mark set by Squid
3717 la Local listening IP address the client connection was connected to.
3718 lp Local listening port number the client connection was connected to.
3720 <a Server IP address of the last server or peer connection
3721 <A Server FQDN or peer name
3722 <p Server port number of the last server or peer connection
3723 <la Local IP address of the last server or peer connection
3724 <lp Local port number of the last server or peer connection
3725 <qos Server connection TOS/DSCP value set by Squid
3726 <nfmark Server connection netfilter mark set by Squid
3728 Time related format codes:
3730 ts Seconds since epoch
3731 tu subsecond time (milliseconds)
3732 tl Local time. Optional strftime format argument
3733 default %d/%b/%Y:%H:%M:%S %z
3734 tg GMT time. Optional strftime format argument
3735 default %d/%b/%Y:%H:%M:%S %z
3736 tr Response time (milliseconds)
3737 dt Total time spent making DNS lookups (milliseconds)
3738 tS Approximate master transaction start time in
3739 <full seconds since epoch>.<fractional seconds> format.
3740 Currently, Squid considers the master transaction
3741 started when a complete HTTP request header initiating
3742 the transaction is received from the client. This is
3743 the same value that Squid uses to calculate transaction
3744 response time when logging %tr to access.log. Currently,
3745 Squid uses millisecond resolution for %tS values,
3746 similar to the default access.log "current time" field
3749 Access Control related format codes:
3751 et Tag returned by external acl
3752 ea Log string returned by external acl
3753 un User name (any available)
3754 ul User name from authentication
3755 ue User name from external acl helper
3756 ui User name from ident
3757 us User name from SSL
3758 credentials Client credentials. The exact meaning depends on
3759 the authentication scheme: For Basic authentication,
3760 it is the password; for Digest, the realm sent by the
3761 client; for NTLM and Negotiate, the client challenge
3762 or client credentials prefixed with "YR " or "KK ".
3764 HTTP related format codes:
3768 [http::]rm Request method (GET/POST etc)
3769 [http::]>rm Request method from client
3770 [http::]<rm Request method sent to server or peer
3771 [http::]ru Request URL from client (historic, filtered for logging)
3772 [http::]>ru Request URL from client
3773 [http::]<ru Request URL sent to server or peer
3774 [http::]>rs Request URL scheme from client
3775 [http::]<rs Request URL scheme sent to server or peer
3776 [http::]>rd Request URL domain from client
3777 [http::]>rd Request URL domain sent to server or peer
3778 [http::]>rP Request URL port from client
3779 [http::]<rP Request URL port sent to server or peer
3780 [http::]rp Request URL path excluding hostname
3781 [http::]>rp Request URL path excluding hostname from client
3782 [http::]<rp Request URL path excluding hostname sent to server or peer
3783 [http::]rv Request protocol version
3784 [http::]>rv Request protocol version from client
3785 [http::]<rv Request protocol version sent to server or peer
3787 [http::]>h Original received request header.
3788 Usually differs from the request header sent by
3789 Squid, although most fields are often preserved.
3790 Accepts optional header field name/value filter
3791 argument using name[:[separator]element] format.
3792 [http::]>ha Received request header after adaptation and
3793 redirection (pre-cache REQMOD vectoring point).
3794 Usually differs from the request header sent by
3795 Squid, although most fields are often preserved.
3796 Optional header name argument as for >h
3801 [http::]<Hs HTTP status code received from the next hop
3802 [http::]>Hs HTTP status code sent to the client
3804 [http::]<h Reply header. Optional header name argument
3807 [http::]mt MIME content type
3812 [http::]st Total size of request + reply traffic with client
3813 [http::]>st Total size of request received from client.
3814 Excluding chunked encoding bytes.
3815 [http::]<st Total size of reply sent to client (after adaptation)
3817 [http::]>sh Size of request headers received from client
3818 [http::]<sh Size of reply headers sent to client (after adaptation)
3820 [http::]<sH Reply high offset sent
3821 [http::]<sS Upstream object size
3823 [http::]<bs Number of HTTP-equivalent message body bytes
3824 received from the next hop, excluding chunked
3825 transfer encoding and control messages.
3826 Generated FTP/Gopher listings are treated as
3832 [http::]<pt Peer response time in milliseconds. The timer starts
3833 when the last request byte is sent to the next hop
3834 and stops when the last response byte is received.
3835 [http::]<tt Total server-side time in milliseconds. The timer
3836 starts with the first connect request (or write I/O)
3837 sent to the first selected peer. The timer stops
3838 with the last I/O with the last peer.
3840 Squid handling related format codes:
3842 Ss Squid request status (TCP_MISS etc)
3843 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3845 SSL-related format codes:
3847 ssl::bump_mode SslBump decision for the transaction:
3849 For CONNECT requests that initiated bumping of
3850 a connection and for any request received on
3851 an already bumped connection, Squid logs the
3852 corresponding SslBump mode ("server-first" or
3853 "client-first"). See the ssl_bump option for
3854 more information about these modes.
3856 A "none" token is logged for requests that
3857 triggered "ssl_bump" ACL evaluation matching
3858 either a "none" rule or no rules at all.
3860 In all other cases, a single dash ("-") is
3863 If ICAP is enabled, the following code becomes available (as
3864 well as ICAP log codes documented with the icap_log option):
3866 icap::tt Total ICAP processing time for the HTTP
3867 transaction. The timer ticks when ICAP
3868 ACLs are checked and when ICAP
3869 transaction is in progress.
3871 If adaptation is enabled the following three codes become available:
3873 adapt::<last_h The header of the last ICAP response or
3874 meta-information from the last eCAP
3875 transaction related to the HTTP transaction.
3876 Like <h, accepts an optional header name
3879 adapt::sum_trs Summed adaptation transaction response
3880 times recorded as a comma-separated list in
3881 the order of transaction start time. Each time
3882 value is recorded as an integer number,
3883 representing response time of one or more
3884 adaptation (ICAP or eCAP) transaction in
3885 milliseconds. When a failed transaction is
3886 being retried or repeated, its time is not
3887 logged individually but added to the
3888 replacement (next) transaction. See also:
3891 adapt::all_trs All adaptation transaction response times.
3892 Same as adaptation_strs but response times of
3893 individual transactions are never added
3894 together. Instead, all transaction response
3895 times are recorded individually.
3897 You can prefix adapt::*_trs format codes with adaptation
3898 service name in curly braces to record response time(s) specific
3899 to that service. For example: %{my_service}adapt::sum_trs
3901 If SSL is enabled, the following formating codes become available:
3903 %ssl::>cert_subject The Subject field of the received client
3904 SSL certificate or a dash ('-') if Squid has
3905 received an invalid/malformed certificate or
3906 no certificate at all. Consider encoding the
3907 logged value because Subject often has spaces.
3909 %ssl::>cert_issuer The Issuer field of the received client
3910 SSL certificate or a dash ('-') if Squid has
3911 received an invalid/malformed certificate or
3912 no certificate at all. Consider encoding the
3913 logged value because Issuer often has spaces.
3915 The default formats available (which do not need re-defining) are:
3917 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3918 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3919 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3920 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3921 logformat useragent %>a [%tl] "%{User-Agent}>h"
3923 NOTE: When the log_mime_hdrs directive is set to ON.
3924 The squid, common and combined formats have a safely encoded copy
3925 of the mime headers appended to each line within a pair of brackets.
3927 NOTE: The common and combined formats are not quite true to the Apache definition.
3928 The logs from Squid contain an extra status and hierarchy code appended.
3932 NAME: access_log cache_access_log
3934 LOC: Config.Log.accesslogs
3935 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3937 Configures whether and how Squid logs HTTP and ICP transactions.
3938 If access logging is enabled, a single line is logged for every
3939 matching HTTP or ICP request. The recommended directive formats are:
3941 access_log <module>:<place> [option ...] [acl acl ...]
3942 access_log none [acl acl ...]
3944 The following directive format is accepted but may be deprecated:
3945 access_log <module>:<place> [<logformat name> [acl acl ...]]
3947 In most cases, the first ACL name must not contain the '=' character
3948 and should not be equal to an existing logformat name. You can always
3949 start with an 'all' ACL to work around those restrictions.
3951 Will log to the specified module:place using the specified format (which
3952 must be defined in a logformat directive) those entries which match
3953 ALL the acl's specified (which must be defined in acl clauses).
3954 If no acl is specified, all requests will be logged to this destination.
3956 ===== Available options for the recommended directive format =====
3958 logformat=name Names log line format (either built-in or
3959 defined by a logformat directive). Defaults
3962 buffer-size=64KB Defines approximate buffering limit for log
3963 records (see buffered_logs). Squid should not
3964 keep more than the specified size and, hence,
3965 should flush records before the buffer becomes
3966 full to avoid overflows under normal
3967 conditions (the exact flushing algorithm is
3968 module-dependent though). The on-error option
3969 controls overflow handling.
3971 on-error=die|drop Defines action on unrecoverable errors. The
3972 'drop' action ignores (i.e., does not log)
3973 affected log records. The default 'die' action
3974 kills the affected worker. The drop action
3975 support has not been tested for modules other
3978 ===== Modules Currently available =====
3980 none Do not log any requests matching these ACL.
3981 Do not specify Place or logformat name.
3983 stdio Write each log line to disk immediately at the completion of
3985 Place: the filename and path to be written.
3987 daemon Very similar to stdio. But instead of writing to disk the log
3988 line is passed to a daemon helper for asychronous handling instead.
3989 Place: varies depending on the daemon.
3991 log_file_daemon Place: the file name and path to be written.
3993 syslog To log each request via syslog facility.
3994 Place: The syslog facility and priority level for these entries.
3995 Place Format: facility.priority
3997 where facility could be any of:
3998 authpriv, daemon, local0 ... local7 or user.
4000 And priority could be any of:
4001 err, warning, notice, info, debug.
4003 udp To send each log line as text data to a UDP receiver.
4004 Place: The destination host name or IP and port.
4005 Place Format: //host:port
4007 tcp To send each log line as text data to a TCP receiver.
4008 Lines may be accumulated before sending (see buffered_logs).
4009 Place: The destination host name or IP and port.
4010 Place Format: //host:port
4013 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4019 LOC: Config.Log.icaplogs
4022 ICAP log files record ICAP transaction summaries, one line per
4025 The icap_log option format is:
4026 icap_log <filepath> [<logformat name> [acl acl ...]]
4027 icap_log none [acl acl ...]]
4029 Please see access_log option documentation for details. The two
4030 kinds of logs share the overall configuration approach and many
4033 ICAP processing of a single HTTP message or transaction may
4034 require multiple ICAP transactions. In such cases, multiple
4035 ICAP transaction log lines will correspond to a single access
4038 ICAP log uses logformat codes that make sense for an ICAP
4039 transaction. Header-related codes are applied to the HTTP header
4040 embedded in an ICAP server response, with the following caveats:
4041 For REQMOD, there is no HTTP response header unless the ICAP
4042 server performed request satisfaction. For RESPMOD, the HTTP
4043 request header is the header sent to the ICAP server. For
4044 OPTIONS, there are no HTTP headers.
4046 The following format codes are also available for ICAP logs:
4048 icap::<A ICAP server IP address. Similar to <A.
4050 icap::<service_name ICAP service name from the icap_service
4051 option in Squid configuration file.
4053 icap::ru ICAP Request-URI. Similar to ru.
4055 icap::rm ICAP request method (REQMOD, RESPMOD, or
4056 OPTIONS). Similar to existing rm.
4058 icap::>st Bytes sent to the ICAP server (TCP payload
4059 only; i.e., what Squid writes to the socket).
4061 icap::<st Bytes received from the ICAP server (TCP
4062 payload only; i.e., what Squid reads from
4065 icap::<bs Number of message body bytes received from the
4066 ICAP server. ICAP message body, if any, usually
4067 includes encapsulated HTTP message headers and
4068 possibly encapsulated HTTP message body. The
4069 HTTP body part is dechunked before its size is
4072 icap::tr Transaction response time (in
4073 milliseconds). The timer starts when
4074 the ICAP transaction is created and
4075 stops when the transaction is completed.
4078 icap::tio Transaction I/O time (in milliseconds). The
4079 timer starts when the first ICAP request
4080 byte is scheduled for sending. The timers
4081 stops when the last byte of the ICAP response
4084 icap::to Transaction outcome: ICAP_ERR* for all
4085 transaction errors, ICAP_OPT for OPTION
4086 transactions, ICAP_ECHO for 204
4087 responses, ICAP_MOD for message
4088 modification, and ICAP_SAT for request
4089 satisfaction. Similar to Ss.
4091 icap::Hs ICAP response status code. Similar to Hs.
4093 icap::>h ICAP request header(s). Similar to >h.
4095 icap::<h ICAP response header(s). Similar to <h.
4097 The default ICAP log format, which can be used without an explicit
4098 definition, is called icap_squid:
4100 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
4102 See also: logformat, log_icap, and %adapt::<last_h
4105 NAME: logfile_daemon
4107 DEFAULT: @DEFAULT_LOGFILED@
4108 LOC: Log::TheConfig.logfile_daemon
4110 Specify the path to the logfile-writing daemon. This daemon is
4111 used to write the access and store logs, if configured.
4113 Squid sends a number of commands to the log daemon:
4114 L<data>\n - logfile data
4119 r<n>\n - set rotate count to <n>
4120 b<n>\n - 1 = buffer output, 0 = don't buffer output
4122 No responses is expected.
4128 Remove this line. Use acls with access_log directives to control access logging
4134 Remove this line. Use acls with icap_log directives to control icap logging
4137 NAME: stats_collection
4139 LOC: Config.accessList.stats_collection
4141 DEFAULT_DOC: Allow logging for all transactions.
4142 COMMENT: allow|deny acl acl...
4144 This options allows you to control which requests gets accounted
4145 in performance counters.
4147 This clause only supports fast acl types.
4148 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4151 NAME: cache_store_log
4154 LOC: Config.Log.store
4156 Logs the activities of the storage manager. Shows which
4157 objects are ejected from the cache, and which objects are
4158 saved and for how long.
4159 There are not really utilities to analyze this data, so you can safely
4160 disable it (the default).
4162 Store log uses modular logging outputs. See access_log for the list
4163 of modules supported.
4166 cache_store_log stdio:@DEFAULT_STORE_LOG@
4167 cache_store_log daemon:@DEFAULT_STORE_LOG@
4170 NAME: cache_swap_state cache_swap_log
4172 LOC: Config.Log.swap
4174 DEFAULT_DOC: Store the journal inside its cache_dir
4176 Location for the cache "swap.state" file. This index file holds
4177 the metadata of objects saved on disk. It is used to rebuild
4178 the cache during startup. Normally this file resides in each
4179 'cache_dir' directory, but you may specify an alternate
4180 pathname here. Note you must give a full filename, not just
4181 a directory. Since this is the index for the whole object
4182 list you CANNOT periodically rotate it!
4184 If %s can be used in the file name it will be replaced with a
4185 a representation of the cache_dir name where each / is replaced
4186 with '.'. This is needed to allow adding/removing cache_dir
4187 lines when cache_swap_log is being used.
4189 If have more than one 'cache_dir', and %s is not used in the name
4190 these swap logs will have names such as:
4196 The numbered extension (which is added automatically)
4197 corresponds to the order of the 'cache_dir' lines in this
4198 configuration file. If you change the order of the 'cache_dir'
4199 lines in this file, these index files will NOT correspond to
4200 the correct 'cache_dir' entry (unless you manually rename
4201 them). We recommend you do NOT use this option. It is
4202 better to keep these index files in each 'cache_dir' directory.
4205 NAME: logfile_rotate
4208 LOC: Config.Log.rotateNumber
4210 Specifies the number of logfile rotations to make when you
4211 type 'squid -k rotate'. The default is 10, which will rotate
4212 with extensions 0 through 9. Setting logfile_rotate to 0 will
4213 disable the file name rotation, but the logfiles are still closed
4214 and re-opened. This will enable you to rename the logfiles
4215 yourself just before sending the rotate signal.
4217 Note, the 'squid -k rotate' command normally sends a USR1
4218 signal to the running squid process. In certain situations
4219 (e.g. on Linux with Async I/O), USR1 is used for other
4220 purposes, so -k rotate uses another signal. It is best to get
4221 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4224 Note, from Squid-3.1 this option is only a default for cache.log,
4225 that log can be rotated separately by using debug_options.
4228 NAME: emulate_httpd_log
4231 Replace this with an access_log directive using the format 'common' or 'combined'.
4234 NAME: log_ip_on_direct
4237 Remove this option from your config. To log server or peer names use %<A in the log format.
4242 DEFAULT: @DEFAULT_MIME_TABLE@
4243 LOC: Config.mimeTablePathname
4245 Path to Squid's icon configuration file.
4247 You shouldn't need to change this, but the default file contains
4248 examples and formatting information if you do.
4254 LOC: Config.onoff.log_mime_hdrs
4257 The Cache can record both the request and the response MIME
4258 headers for each HTTP transaction. The headers are encoded
4259 safely and will appear as two bracketed fields at the end of
4260 the access log (for either the native or httpd-emulated log
4261 formats). To enable this logging set log_mime_hdrs to 'on'.
4267 Replace this with an access_log directive using the format 'useragent'.
4270 NAME: referer_log referrer_log
4273 Replace this with an access_log directive using the format 'referrer'.
4278 DEFAULT: @DEFAULT_PID_FILE@
4279 LOC: Config.pidFilename
4281 A filename to write the process-id to. To disable, enter "none".
4287 Remove this option from your config. To log FQDN use %>A in the log format.
4290 NAME: client_netmask
4292 LOC: Config.Addrs.client_netmask
4294 DEFAULT_DOC: Log full client IP address
4296 A netmask for client addresses in logfiles and cachemgr output.
4297 Change this to protect the privacy of your cache clients.
4298 A netmask of 255.255.255.0 will log all IP's in that range with
4299 the last digit set to '0'.
4305 Use a regular access.log with ACL limiting it to MISS events.
4308 NAME: strip_query_terms
4310 LOC: Config.onoff.strip_query_terms
4313 By default, Squid strips query terms from requested URLs before
4314 logging. This protects your user's privacy and reduces log size.
4316 When investigating HIT/MISS or other caching behaviour you
4317 will need to disable this to see the full URL used by Squid.
4324 LOC: Config.onoff.buffered_logs
4326 Whether to write/send access_log records ASAP or accumulate them and
4327 then write/send them in larger chunks. Buffering may improve
4328 performance because it decreases the number of I/Os. However,
4329 buffering increases the delay before log records become available to
4330 the final recipient (e.g., a disk file or logging daemon) and,
4331 hence, increases the risk of log records loss.
4333 Note that even when buffered_logs are off, Squid may have to buffer
4334 records if it cannot write/send them immediately due to pending I/Os
4335 (e.g., the I/O writing the previous log record) or connectivity loss.
4337 Currently honored by 'daemon' and 'tcp' access_log modules only.
4340 NAME: netdb_filename
4342 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4343 LOC: Config.netdbFilename
4346 Where Squid stores it's netdb journal.
4347 When enabled this journal preserves netdb state between restarts.
4349 To disable, enter "none".
4353 OPTIONS FOR TROUBLESHOOTING
4354 -----------------------------------------------------------------------------
4359 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4360 LOC: Debug::cache_log
4362 Squid administrative logging file.
4364 This is where general information about Squid behavior goes. You can
4365 increase the amount of data logged to this file and how often it is
4366 rotated with "debug_options"
4372 DEFAULT_DOC: Log all critical and important messages.
4373 LOC: Debug::debugOptions
4375 Logging options are set as section,level where each source file
4376 is assigned a unique section. Lower levels result in less
4377 output, Full debugging (level 9) can result in a very large
4378 log file, so be careful.
4380 The magic word "ALL" sets debugging levels for all sections.
4381 The default is to run with "ALL,1" to record important warnings.
4383 The rotate=N option can be used to keep more or less of these logs
4384 than would otherwise be kept by logfile_rotate.
4385 For most uses a single log should be enough to monitor current
4386 events affecting Squid.
4391 LOC: Config.coredump_dir
4392 DEFAULT_IF_NONE: none
4393 DEFAULT_DOC: Use the directory from where Squid was started.
4395 By default Squid leaves core files in the directory from where
4396 it was started. If you set 'coredump_dir' to a directory
4397 that exists, Squid will chdir() to that directory at startup
4398 and coredump files will be left there.
4402 # Leave coredumps in the first cache dir
4403 coredump_dir @DEFAULT_SWAP_DIR@
4409 OPTIONS FOR FTP GATEWAYING
4410 -----------------------------------------------------------------------------
4416 LOC: Config.Ftp.anon_user
4418 If you want the anonymous login password to be more informative
4419 (and enable the use of picky FTP servers), set this to something
4420 reasonable for your domain, like wwwuser@somewhere.net
4422 The reason why this is domainless by default is the
4423 request can be made on the behalf of a user in any domain,
4424 depending on how the cache is used.
4425 Some FTP server also validate the email address is valid
4426 (for example perl.com).
4432 LOC: Config.Ftp.passive
4434 If your firewall does not allow Squid to use passive
4435 connections, turn off this option.
4437 Use of ftp_epsv_all option requires this to be ON.
4443 LOC: Config.Ftp.epsv_all
4445 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4447 NATs may be able to put the connection on a "fast path" through the
4448 translator, as the EPRT command will never be used and therefore,
4449 translation of the data portion of the segments will never be needed.
4451 When a client only expects to do two-way FTP transfers this may be
4453 If squid finds that it must do a three-way FTP transfer after issuing
4454 an EPSV ALL command, the FTP session will fail.
4456 If you have any doubts about this option do not use it.
4457 Squid will nicely attempt all other connection methods.
4459 Requires ftp_passive to be ON (default) for any effect.
4465 LOC: Config.accessList.ftp_epsv
4467 FTP Protocol extensions permit the use of a special "EPSV" command.
4469 NATs may be able to put the connection on a "fast path" through the
4470 translator using EPSV, as the EPRT command will never be used
4471 and therefore, translation of the data portion of the segments
4472 will never be needed.
4474 EPSV is often required to interoperate with FTP servers on IPv6
4475 networks. On the other hand, it may break some IPv4 servers.
4477 By default, EPSV may try EPSV with any FTP server. To fine tune
4478 that decision, you may restrict EPSV to certain clients or servers
4481 ftp_epsv allow|deny al1 acl2 ...
4483 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
4485 Only fast ACLs are supported.
4486 Requires ftp_passive to be ON (default) for any effect.
4492 LOC: Config.Ftp.eprt
4494 FTP Protocol extensions permit the use of a special "EPRT" command.
4496 This extension provides a protocol neutral alternative to the
4497 IPv4-only PORT command. When supported it enables active FTP data
4498 channels over IPv6 and efficient NAT handling.
4500 Turning this OFF will prevent EPRT being attempted and will skip
4501 straight to using PORT for IPv4 servers.
4503 Some devices are known to not handle this extension correctly and
4504 may result in crashes. Devices which suport EPRT enough to fail
4505 cleanly will result in Squid attempting PORT anyway. This directive
4506 should only be disabled when EPRT results in device failures.
4508 WARNING: Doing so will convert Squid back to the old behavior with all
4509 the related problems with external NAT devices/layers and IPv4-only FTP.
4512 NAME: ftp_sanitycheck
4515 LOC: Config.Ftp.sanitycheck
4517 For security and data integrity reasons Squid by default performs
4518 sanity checks of the addresses of FTP data connections ensure the
4519 data connection is to the requested server. If you need to allow
4520 FTP connections to servers using another IP address for the data
4521 connection turn this off.
4524 NAME: ftp_telnet_protocol
4527 LOC: Config.Ftp.telnet
4529 The FTP protocol is officially defined to use the telnet protocol
4530 as transport channel for the control connection. However, many
4531 implementations are broken and does not respect this aspect of
4534 If you have trouble accessing files with ASCII code 255 in the
4535 path or similar problems involving this ASCII code you can
4536 try setting this directive to off. If that helps, report to the
4537 operator of the FTP server in question that their FTP server
4538 is broken and does not follow the FTP standard.
4542 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4543 -----------------------------------------------------------------------------
4548 DEFAULT: @DEFAULT_DISKD@
4549 LOC: Config.Program.diskd
4551 Specify the location of the diskd executable.
4552 Note this is only useful if you have compiled in
4553 diskd as one of the store io modules.
4556 NAME: unlinkd_program
4559 DEFAULT: @DEFAULT_UNLINKD@
4560 LOC: Config.Program.unlinkd
4562 Specify the location of the executable for file deletion process.
4565 NAME: pinger_program
4567 DEFAULT: @DEFAULT_PINGER@
4568 LOC: Config.pinger.program
4571 Specify the location of the executable for the pinger process.
4577 LOC: Config.pinger.enable
4580 Control whether the pinger is active at run-time.
4581 Enables turning ICMP pinger on and off with a simple
4582 squid -k reconfigure.
4587 OPTIONS FOR URL REWRITING
4588 -----------------------------------------------------------------------------
4591 NAME: url_rewrite_program redirect_program
4593 LOC: Config.Program.redirect
4596 Specify the location of the executable URL rewriter to use.
4597 Since they can perform almost any function there isn't one included.
4599 For each requested URL, the rewriter will receive on line with the format
4601 [channel-ID <SP>] URL [<SP> extras]<NL>
4603 See url_rewrite_extras on how to send "extras" with optional values to
4605 After processing the request the helper must reply using the following format:
4607 [channel-ID <SP>] result [<SP> kv-pairs]
4609 The result code can be:
4611 OK status=30N url="..."
4612 Redirect the URL to the one supplied in 'url='.
4613 'status=' is optional and contains the status code to send
4614 the client in Squids HTTP response. It must be one of the
4615 HTTP redirect status codes: 301, 302, 303, 307, 308.
4616 When no status is given Squid will use 302.
4618 OK rewrite-url="..."
4619 Rewrite the URL to the one supplied in 'rewrite-url='.
4620 The new URL is fetched directly by Squid and returned to
4621 the client as the response to its request.
4624 When neither of url= and rewrite-url= are sent Squid does
4628 Do not change the URL.
4631 An internal error occurred in the helper, preventing
4632 a result being identified. The 'message=' key name is
4633 reserved for delivering a log message.
4636 In addition to the above kv-pairs Squid also understands the following
4637 optional kv-pairs received from URL rewriters:
4639 Associates a TAG with the client TCP connection.
4640 The TAG is treated as a regular annotation but persists across
4641 future requests on the client connection rather than just the
4642 current request. A helper may update the TAG during subsequent
4643 requests be returning a new kv-pair.
4645 When using the concurrency= option the protocol is changed by
4646 introducing a query channel tag in front of the request/response.
4647 The query channel tag is a number between 0 and concurrency-1.
4648 This value must be echoed back unchanged to Squid as the first part
4649 of the response relating to its request.
4651 WARNING: URL re-writing ability should be avoided whenever possible.
4652 Use the URL redirect form of response instead.
4654 Re-write creates a difference in the state held by the client
4655 and server. Possibly causing confusion when the server response
4656 contains snippets of its view state. Embeded URLs, response
4657 and content Location headers, etc. are not re-written by this
4660 By default, a URL rewriter is not used.
4663 NAME: url_rewrite_children redirect_children
4664 TYPE: HelperChildConfig
4665 DEFAULT: 20 startup=0 idle=1 concurrency=0
4666 LOC: Config.redirectChildren
4668 The maximum number of redirector processes to spawn. If you limit
4669 it too few Squid will have to wait for them to process a backlog of
4670 URLs, slowing it down. If you allow too many they will use RAM
4671 and other system resources noticably.
4673 The startup= and idle= options allow some measure of skew in your
4678 Sets a minimum of how many processes are to be spawned when Squid
4679 starts or reconfigures. When set to zero the first request will
4680 cause spawning of the first child process to handle it.
4682 Starting too few will cause an initial slowdown in traffic as Squid
4683 attempts to simultaneously spawn enough processes to cope.
4687 Sets a minimum of how many processes Squid is to try and keep available
4688 at all times. When traffic begins to rise above what the existing
4689 processes can handle this many more will be spawned up to the maximum
4690 configured. A minimum setting of 1 is required.
4694 The number of requests each redirector helper can handle in
4695 parallel. Defaults to 0 which indicates the redirector
4696 is a old-style single threaded redirector.
4698 When this directive is set to a value >= 1 then the protocol
4699 used to communicate with the helper is modified to include
4700 an ID in front of the request/response. The ID from the request
4701 must be echoed back with the response to that request.
4704 NAME: url_rewrite_host_header redirect_rewrites_host_header
4707 LOC: Config.onoff.redir_rewrites_host
4709 To preserve same-origin security policies in browsers and
4710 prevent Host: header forgery by redirectors Squid rewrites
4711 any Host: header in redirected requests.
4713 If you are running an accelerator this may not be a wanted
4714 effect of a redirector. This directive enables you disable
4715 Host: alteration in reverse-proxy traffic.
4717 WARNING: Entries are cached on the result of the URL rewriting
4718 process, so be careful if you have domain-virtual hosts.
4720 WARNING: Squid and other software verifies the URL and Host
4721 are matching, so be careful not to relay through other proxies
4722 or inspecting firewalls with this disabled.
4725 NAME: url_rewrite_access redirector_access
4728 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4729 LOC: Config.accessList.redirector
4731 If defined, this access list specifies which requests are
4732 sent to the redirector processes.
4734 This clause supports both fast and slow acl types.
4735 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4738 NAME: url_rewrite_bypass redirector_bypass
4740 LOC: Config.onoff.redirector_bypass
4743 When this is 'on', a request will not go through the
4744 redirector if all the helpers are busy. If this is 'off'
4745 and the redirector queue grows too large, Squid will exit
4746 with a FATAL error and ask you to increase the number of
4747 redirectors. You should only enable this if the redirectors
4748 are not critical to your caching system. If you use
4749 redirectors for access control, and you enable this option,
4750 users may have access to pages they should not
4751 be allowed to request.
4754 NAME: url_rewrite_extras
4755 TYPE: TokenOrQuotedString
4756 LOC: Config.redirector_extras
4757 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
4759 Specifies a string to be append to request line format for the
4760 rewriter helper. "Quoted" format values may contain spaces and
4761 logformat %macros. In theory, any logformat %macro can be used.
4762 In practice, a %macro expands as a dash (-) if the helper request is
4763 sent before the required macro information is available to Squid.
4767 OPTIONS FOR STORE ID
4768 -----------------------------------------------------------------------------
4771 NAME: store_id_program storeurl_rewrite_program
4773 LOC: Config.Program.store_id
4776 Specify the location of the executable StoreID helper to use.
4777 Since they can perform almost any function there isn't one included.
4779 For each requested URL, the helper will receive one line with the format
4781 [channel-ID <SP>] URL [<SP> extras]<NL>
4784 After processing the request the helper must reply using the following format:
4786 [channel-ID <SP>] result [<SP> kv-pairs]
4788 The result code can be:
4791 Use the StoreID supplied in 'store-id='.
4794 The default is to use HTTP request URL as the store ID.
4797 An internal error occured in the helper, preventing
4798 a result being identified.
4800 In addition to the above kv-pairs Squid also understands the following
4801 optional kv-pairs received from URL rewriters:
4803 Associates a TAG with the client TCP connection.
4804 Please see url_rewrite_program related documentation for this
4807 Helper programs should be prepared to receive and possibly ignore
4808 additional whitespace-separated tokens on each input line.
4810 When using the concurrency= option the protocol is changed by
4811 introducing a query channel tag in front of the request/response.
4812 The query channel tag is a number between 0 and concurrency-1.
4813 This value must be echoed back unchanged to Squid as the first part
4814 of the response relating to its request.
4816 NOTE: when using StoreID refresh_pattern will apply to the StoreID
4817 returned from the helper and not the URL.
4819 WARNING: Wrong StoreID value returned by a careless helper may result
4820 in the wrong cached response returned to the user.
4822 By default, a StoreID helper is not used.
4825 NAME: store_id_extras
4826 TYPE: TokenOrQuotedString
4827 LOC: Config.storeId_extras
4828 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
4830 Specifies a string to be append to request line format for the
4831 StoreId helper. "Quoted" format values may contain spaces and
4832 logformat %macros. In theory, any logformat %macro can be used.
4833 In practice, a %macro expands as a dash (-) if the helper request is
4834 sent before the required macro information is available to Squid.
4837 NAME: store_id_children storeurl_rewrite_children
4838 TYPE: HelperChildConfig
4839 DEFAULT: 20 startup=0 idle=1 concurrency=0
4840 LOC: Config.storeIdChildren
4842 The maximum number of StoreID helper processes to spawn. If you limit
4843 it too few Squid will have to wait for them to process a backlog of
4844 requests, slowing it down. If you allow too many they will use RAM
4845 and other system resources noticably.
4847 The startup= and idle= options allow some measure of skew in your
4852 Sets a minimum of how many processes are to be spawned when Squid
4853 starts or reconfigures. When set to zero the first request will
4854 cause spawning of the first child process to handle it.
4856 Starting too few will cause an initial slowdown in traffic as Squid
4857 attempts to simultaneously spawn enough processes to cope.
4861 Sets a minimum of how many processes Squid is to try and keep available
4862 at all times. When traffic begins to rise above what the existing
4863 processes can handle this many more will be spawned up to the maximum
4864 configured. A minimum setting of 1 is required.
4868 The number of requests each storeID helper can handle in
4869 parallel. Defaults to 0 which indicates the helper
4870 is a old-style single threaded program.
4872 When this directive is set to a value >= 1 then the protocol
4873 used to communicate with the helper is modified to include
4874 an ID in front of the request/response. The ID from the request
4875 must be echoed back with the response to that request.
4878 NAME: store_id_access storeurl_rewrite_access
4881 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4882 LOC: Config.accessList.store_id
4884 If defined, this access list specifies which requests are
4885 sent to the StoreID processes. By default all requests
4888 This clause supports both fast and slow acl types.
4889 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4892 NAME: store_id_bypass storeurl_rewrite_bypass
4894 LOC: Config.onoff.store_id_bypass
4897 When this is 'on', a request will not go through the
4898 helper if all helpers are busy. If this is 'off'
4899 and the helper queue grows too large, Squid will exit
4900 with a FATAL error and ask you to increase the number of
4901 helpers. You should only enable this if the helperss
4902 are not critical to your caching system. If you use
4903 helpers for critical caching components, and you enable this
4904 option, users may not get objects from cache.
4908 OPTIONS FOR TUNING THE CACHE
4909 -----------------------------------------------------------------------------
4912 NAME: cache no_cache
4915 DEFAULT_DOC: By default, this directive is unused and has no effect.
4916 LOC: Config.accessList.noCache
4918 Requests denied by this directive will not be served from the cache
4919 and their responses will not be stored in the cache. This directive
4920 has no effect on other transactions and on already cached responses.
4922 This clause supports both fast and slow acl types.
4923 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4925 This and the two other similar caching directives listed below are
4926 checked at different transaction processing stages, have different
4927 access to response information, affect different cache operations,
4928 and differ in slow ACLs support:
4930 * cache: Checked before Squid makes a hit/miss determination.
4931 No access to reply information!
4932 Denies both serving a hit and storing a miss.
4933 Supports both fast and slow ACLs.
4934 * send_hit: Checked after a hit was detected.
4935 Has access to reply (hit) information.
4936 Denies serving a hit only.
4937 Supports fast ACLs only.
4938 * store_miss: Checked before storing a cachable miss.
4939 Has access to reply (miss) information.
4940 Denies storing a miss only.
4941 Supports fast ACLs only.
4943 If you are not sure which of the three directives to use, apply the
4944 following decision logic:
4946 * If your ACL(s) are of slow type _and_ need response info, redesign.
4947 Squid does not support that particular combination at this time.
4949 * If your directive ACL(s) are of slow type, use "cache"; and/or
4950 * if your directive ACL(s) need no response info, use "cache".
4952 * If you do not want the response cached, use store_miss; and/or
4953 * if you do not want a hit on a cached response, use send_hit.
4959 DEFAULT_DOC: By default, this directive is unused and has no effect.
4960 LOC: Config.accessList.sendHit
4962 Responses denied by this directive will not be served from the cache
4963 (but may still be cached, see store_miss). This directive has no
4964 effect on the responses it allows and on the cached objects.
4966 Please see the "cache" directive for a summary of differences among
4967 store_miss, send_hit, and cache directives.
4969 Unlike the "cache" directive, send_hit only supports fast acl
4970 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4974 # apply custom Store ID mapping to some URLs
4975 acl MapMe dstdomain .c.example.com
4976 store_id_program ...
4977 store_id_access allow MapMe
4979 # but prevent caching of special responses
4980 # such as 302 redirects that cause StoreID loops
4981 acl Ordinary http_status 200-299
4982 store_miss deny MapMe !Ordinary
4984 # and do not serve any previously stored special responses
4985 # from the cache (in case they were already cached before
4986 # the above store_miss rule was in effect).
4987 send_hit deny MapMe !Ordinary
4993 DEFAULT_DOC: By default, this directive is unused and has no effect.
4994 LOC: Config.accessList.storeMiss
4996 Responses denied by this directive will not be cached (but may still
4997 be served from the cache, see send_hit). This directive has no
4998 effect on the responses it allows and on the already cached responses.
5000 Please see the "cache" directive for a summary of differences among
5001 store_miss, send_hit, and cache directives. See the
5002 send_hit directive for a usage example.
5004 Unlike the "cache" directive, store_miss only supports fast acl
5005 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5011 LOC: Config.maxStale
5014 This option puts an upper limit on how stale content Squid
5015 will serve from the cache if cache validation fails.
5016 Can be overriden by the refresh_pattern max-stale option.
5019 NAME: refresh_pattern
5020 TYPE: refreshpattern
5024 usage: refresh_pattern [-i] regex min percent max [options]
5026 By default, regular expressions are CASE-SENSITIVE. To make
5027 them case-insensitive, use the -i option.
5029 'Min' is the time (in minutes) an object without an explicit
5030 expiry time should be considered fresh. The recommended
5031 value is 0, any higher values may cause dynamic applications
5032 to be erroneously cached unless the application designer
5033 has taken the appropriate actions.
5035 'Percent' is a percentage of the objects age (time since last
5036 modification age) an object without explicit expiry time
5037 will be considered fresh.
5039 'Max' is an upper limit on how long objects without an explicit
5040 expiry time will be considered fresh.
5042 options: override-expire
5047 ignore-must-revalidate
5054 override-expire enforces min age even if the server
5055 sent an explicit expiry time (e.g., with the
5056 Expires: header or Cache-Control: max-age). Doing this
5057 VIOLATES the HTTP standard. Enabling this feature
5058 could make you liable for problems which it causes.
5060 Note: override-expire does not enforce staleness - it only extends
5061 freshness / min. If the server returns a Expires time which
5062 is longer than your max time, Squid will still consider
5063 the object fresh for that period of time.
5065 override-lastmod enforces min age even on objects
5066 that were modified recently.
5068 reload-into-ims changes a client no-cache or ``reload''
5069 request for a cached entry into a conditional request using
5070 If-Modified-Since and/or If-None-Match headers, provided the
5071 cached entry has a Last-Modified and/or a strong ETag header.
5072 Doing this VIOLATES the HTTP standard. Enabling this feature
5073 could make you liable for problems which it causes.
5075 ignore-reload ignores a client no-cache or ``reload''
5076 header. Doing this VIOLATES the HTTP standard. Enabling
5077 this feature could make you liable for problems which
5080 ignore-no-store ignores any ``Cache-control: no-store''
5081 headers received from a server. Doing this VIOLATES
5082 the HTTP standard. Enabling this feature could make you
5083 liable for problems which it causes.
5085 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
5086 headers received from a server. Doing this VIOLATES
5087 the HTTP standard. Enabling this feature could make you
5088 liable for problems which it causes.
5090 ignore-private ignores any ``Cache-control: private''
5091 headers received from a server. Doing this VIOLATES
5092 the HTTP standard. Enabling this feature could make you
5093 liable for problems which it causes.
5095 ignore-auth caches responses to requests with authorization,
5096 as if the originserver had sent ``Cache-control: public''
5097 in the response header. Doing this VIOLATES the HTTP standard.
5098 Enabling this feature could make you liable for problems which
5101 refresh-ims causes squid to contact the origin server
5102 when a client issues an If-Modified-Since request. This
5103 ensures that the client will receive an updated version
5104 if one is available.
5106 store-stale stores responses even if they don't have explicit
5107 freshness or a validator (i.e., Last-Modified or an ETag)
5108 present, or if they're already stale. By default, Squid will
5109 not cache such responses because they usually can't be
5110 reused. Note that such responses will be stale by default.
5112 max-stale=NN provide a maximum staleness factor. Squid won't
5113 serve objects more stale than this even if it failed to
5114 validate the object. Default: use the max_stale global limit.
5116 Basically a cached object is:
5118 FRESH if expires < now, else STALE
5120 FRESH if lm-factor < percent, else STALE
5124 The refresh_pattern lines are checked in the order listed here.
5125 The first entry which matches is used. If none of the entries
5126 match the default will be used.
5128 Note, you must uncomment all the default lines if you want
5129 to change one. The default setting is only active if none is
5135 # Add any of your own refresh_pattern entries above these.
5137 refresh_pattern ^ftp: 1440 20% 10080
5138 refresh_pattern ^gopher: 1440 0% 1440
5139 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5140 refresh_pattern . 0 20% 4320
5144 NAME: quick_abort_min
5148 LOC: Config.quickAbort.min
5151 NAME: quick_abort_max
5155 LOC: Config.quickAbort.max
5158 NAME: quick_abort_pct
5162 LOC: Config.quickAbort.pct
5164 The cache by default continues downloading aborted requests
5165 which are almost completed (less than 16 KB remaining). This
5166 may be undesirable on slow (e.g. SLIP) links and/or very busy
5167 caches. Impatient users may tie up file descriptors and
5168 bandwidth by repeatedly requesting and immediately aborting
5171 When the user aborts a request, Squid will check the
5172 quick_abort values to the amount of data transferred until
5175 If the transfer has less than 'quick_abort_min' KB remaining,
5176 it will finish the retrieval.
5178 If the transfer has more than 'quick_abort_max' KB remaining,
5179 it will abort the retrieval.
5181 If more than 'quick_abort_pct' of the transfer has completed,
5182 it will finish the retrieval.
5184 If you do not want any retrieval to continue after the client
5185 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5188 If you want retrievals to always continue if they are being
5189 cached set 'quick_abort_min' to '-1 KB'.
5192 NAME: read_ahead_gap
5193 COMMENT: buffer-size
5195 LOC: Config.readAheadGap
5198 The amount of data the cache will buffer ahead of what has been
5199 sent to the client when retrieving an object from another server.
5203 IFDEF: USE_HTTP_VIOLATIONS
5206 LOC: Config.negativeTtl
5209 Set the Default Time-to-Live (TTL) for failed requests.
5210 Certain types of failures (such as "connection refused" and
5211 "404 Not Found") are able to be negatively-cached for a short time.
5212 Modern web servers should provide Expires: header, however if they
5213 do not this can provide a minimum TTL.
5214 The default is not to cache errors with unknown expiry details.
5216 Note that this is different from negative caching of DNS lookups.
5218 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5219 this feature could make you liable for problems which it
5223 NAME: positive_dns_ttl
5226 LOC: Config.positiveDnsTtl
5229 Upper limit on how long Squid will cache positive DNS responses.
5230 Default is 6 hours (360 minutes). This directive must be set
5231 larger than negative_dns_ttl.
5234 NAME: negative_dns_ttl
5237 LOC: Config.negativeDnsTtl
5240 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5241 This also sets the lower cache limit on positive lookups.
5242 Minimum value is 1 second, and it is not recommendable to go
5243 much below 10 seconds.
5246 NAME: range_offset_limit
5247 COMMENT: size [acl acl...]
5249 LOC: Config.rangeOffsetLimit
5252 usage: (size) [units] [[!]aclname]
5254 Sets an upper limit on how far (number of bytes) into the file
5255 a Range request may be to cause Squid to prefetch the whole file.
5256 If beyond this limit, Squid forwards the Range request as it is and
5257 the result is NOT cached.
5259 This is to stop a far ahead range request (lets say start at 17MB)
5260 from making Squid fetch the whole object up to that point before
5261 sending anything to the client.
5263 Multiple range_offset_limit lines may be specified, and they will
5264 be searched from top to bottom on each request until a match is found.
5265 The first match found will be used. If no line matches a request, the
5266 default limit of 0 bytes will be used.
5268 'size' is the limit specified as a number of units.
5270 'units' specifies whether to use bytes, KB, MB, etc.
5271 If no units are specified bytes are assumed.
5273 A size of 0 causes Squid to never fetch more than the
5274 client requested. (default)
5276 A size of 'none' causes Squid to always fetch the object from the
5277 beginning so it may cache the result. (2.0 style)
5279 'aclname' is the name of a defined ACL.
5281 NP: Using 'none' as the byte value here will override any quick_abort settings
5282 that may otherwise apply to the range request. The range request will
5283 be fully fetched from start to finish regardless of the client
5284 actions. This affects bandwidth usage.
5287 NAME: minimum_expiry_time
5290 LOC: Config.minimum_expiry_time
5293 The minimum caching time according to (Expires - Date)
5294 headers Squid honors if the object can't be revalidated.
5295 The default is 60 seconds.
5297 In reverse proxy environments it might be desirable to honor
5298 shorter object lifetimes. It is most likely better to make
5299 your server return a meaningful Last-Modified header however.
5301 In ESI environments where page fragments often have short
5302 lifetimes, this will often be best set to 0.
5305 NAME: store_avg_object_size
5309 LOC: Config.Store.avgObjectSize
5311 Average object size, used to estimate number of objects your
5312 cache can hold. The default is 13 KB.
5314 This is used to pre-seed the cache index memory allocation to
5315 reduce expensive reallocate operations while handling clients
5316 traffic. Too-large values may result in memory allocation during
5317 peak traffic, too-small values will result in wasted memory.
5319 Check the cache manager 'info' report metrics for the real
5320 object sizes seen by your Squid before tuning this.
5323 NAME: store_objects_per_bucket
5326 LOC: Config.Store.objectsPerBucket
5328 Target number of objects per bucket in the store hash table.
5329 Lowering this value increases the total number of buckets and
5330 also the storage maintenance rate. The default is 20.
5335 -----------------------------------------------------------------------------
5338 NAME: request_header_max_size
5342 LOC: Config.maxRequestHeaderSize
5344 This specifies the maximum size for HTTP headers in a request.
5345 Request headers are usually relatively small (about 512 bytes).
5346 Placing a limit on the request header size will catch certain
5347 bugs (for example with persistent connections) and possibly
5348 buffer-overflow or denial-of-service attacks.
5351 NAME: reply_header_max_size
5355 LOC: Config.maxReplyHeaderSize
5357 This specifies the maximum size for HTTP headers in a reply.
5358 Reply headers are usually relatively small (about 512 bytes).
5359 Placing a limit on the reply header size will catch certain
5360 bugs (for example with persistent connections) and possibly
5361 buffer-overflow or denial-of-service attacks.
5364 NAME: request_body_max_size
5368 DEFAULT_DOC: No limit.
5369 LOC: Config.maxRequestBodySize
5371 This specifies the maximum size for an HTTP request body.
5372 In other words, the maximum size of a PUT/POST request.
5373 A user who attempts to send a request with a body larger
5374 than this limit receives an "Invalid Request" error message.
5375 If you set this parameter to a zero (the default), there will
5376 be no limit imposed.
5378 See also client_request_buffer_max_size for an alternative
5379 limitation on client uploads which can be configured.
5382 NAME: client_request_buffer_max_size
5386 LOC: Config.maxRequestBufferSize
5388 This specifies the maximum buffer size of a client request.
5389 It prevents squid eating too much memory when somebody uploads
5393 NAME: chunked_request_body_max_size
5397 LOC: Config.maxChunkedRequestBodySize
5399 A broken or confused HTTP/1.1 client may send a chunked HTTP
5400 request to Squid. Squid does not have full support for that
5401 feature yet. To cope with such requests, Squid buffers the
5402 entire request and then dechunks request body to create a
5403 plain HTTP/1.0 request with a known content length. The plain
5404 request is then used by the rest of Squid code as usual.
5406 The option value specifies the maximum size of the buffer used
5407 to hold the request before the conversion. If the chunked
5408 request size exceeds the specified limit, the conversion
5409 fails, and the client receives an "unsupported request" error,
5410 as if dechunking was disabled.
5412 Dechunking is enabled by default. To disable conversion of
5413 chunked requests, set the maximum to zero.
5415 Request dechunking feature and this option in particular are a
5416 temporary hack. When chunking requests and responses are fully
5417 supported, there will be no need to buffer a chunked request.
5421 IFDEF: USE_HTTP_VIOLATIONS
5424 DEFAULT_DOC: Obey RFC 2616.
5425 LOC: Config.accessList.brokenPosts
5427 A list of ACL elements which, if matched, causes Squid to send
5428 an extra CRLF pair after the body of a PUT/POST request.
5430 Some HTTP servers has broken implementations of PUT/POST,
5431 and rely on an extra CRLF pair sent by some WWW clients.
5433 Quote from RFC2616 section 4.1 on this matter:
5435 Note: certain buggy HTTP/1.0 client implementations generate an
5436 extra CRLF's after a POST request. To restate what is explicitly
5437 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5438 a request with an extra CRLF.
5440 This clause only supports fast acl types.
5441 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5444 acl buggy_server url_regex ^http://....
5445 broken_posts allow buggy_server
5448 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5451 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5453 LOC: Adaptation::Config::use_indirect_client
5455 Controls whether the indirect client IP address (instead of the direct
5456 client IP address) is passed to adaptation services.
5458 See also: follow_x_forwarded_for adaptation_send_client_ip
5462 IFDEF: USE_HTTP_VIOLATIONS
5466 LOC: Config.onoff.via
5468 If set (default), Squid will include a Via header in requests and
5469 replies as required by RFC2616.
5475 LOC: Config.onoff.ie_refresh
5478 Microsoft Internet Explorer up until version 5.5 Service
5479 Pack 1 has an issue with transparent proxies, wherein it
5480 is impossible to force a refresh. Turning this on provides
5481 a partial fix to the problem, by causing all IMS-REFRESH
5482 requests from older IE versions to check the origin server
5483 for fresh content. This reduces hit ratio by some amount
5484 (~10% in my experience), but allows users to actually get
5485 fresh content when they want it. Note because Squid
5486 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5487 of 5.5 is unchanged from old versions of Squid (i.e. a
5488 forced refresh is impossible). Newer versions of IE will,
5489 hopefully, continue to have the new behavior and will be
5490 handled based on that assumption. This option defaults to
5491 the old Squid behavior, which is better for hit ratios but
5492 worse for clients using IE, if they need to be able to
5493 force fresh content.
5496 NAME: vary_ignore_expire
5499 LOC: Config.onoff.vary_ignore_expire
5502 Many HTTP servers supporting Vary gives such objects
5503 immediate expiry time with no cache-control header
5504 when requested by a HTTP/1.0 client. This option
5505 enables Squid to ignore such expiry times until
5506 HTTP/1.1 is fully implemented.
5508 WARNING: If turned on this may eventually cause some
5509 varying objects not intended for caching to get cached.
5512 NAME: request_entities
5514 LOC: Config.onoff.request_entities
5517 Squid defaults to deny GET and HEAD requests with request entities,
5518 as the meaning of such requests are undefined in the HTTP standard
5519 even if not explicitly forbidden.
5521 Set this directive to on if you have clients which insists
5522 on sending request entities in GET or HEAD requests. But be warned
5523 that there is server software (both proxies and web servers) which
5524 can fail to properly process this kind of request which may make you
5525 vulnerable to cache pollution attacks if enabled.
5528 NAME: request_header_access
5529 IFDEF: USE_HTTP_VIOLATIONS
5530 TYPE: http_header_access
5531 LOC: Config.request_header_access
5533 DEFAULT_DOC: No limits.
5535 Usage: request_header_access header_name allow|deny [!]aclname ...
5537 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5538 this feature could make you liable for problems which it
5541 This option replaces the old 'anonymize_headers' and the
5542 older 'http_anonymizer' option with something that is much
5543 more configurable. A list of ACLs for each header name allows
5544 removal of specific header fields under specific conditions.
5546 This option only applies to outgoing HTTP request headers (i.e.,
5547 headers sent by Squid to the next HTTP hop such as a cache peer
5548 or an origin server). The option has no effect during cache hit
5549 detection. The equivalent adaptation vectoring point in ICAP
5550 terminology is post-cache REQMOD.
5552 The option is applied to individual outgoing request header
5553 fields. For each request header field F, Squid uses the first
5554 qualifying sets of request_header_access rules:
5556 1. Rules with header_name equal to F's name.
5557 2. Rules with header_name 'Other', provided F's name is not
5558 on the hard-coded list of commonly used HTTP header names.
5559 3. Rules with header_name 'All'.
5561 Within that qualifying rule set, rule ACLs are checked as usual.
5562 If ACLs of an "allow" rule match, the header field is allowed to
5563 go through as is. If ACLs of a "deny" rule match, the header is
5564 removed and request_header_replace is then checked to identify
5565 if the removed header has a replacement. If no rules within the
5566 set have matching ACLs, the header field is left as is.
5568 For example, to achieve the same behavior as the old
5569 'http_anonymizer standard' option, you should use:
5571 request_header_access From deny all
5572 request_header_access Referer deny all
5573 request_header_access User-Agent deny all
5575 Or, to reproduce the old 'http_anonymizer paranoid' feature
5578 request_header_access Authorization allow all
5579 request_header_access Proxy-Authorization allow all
5580 request_header_access Cache-Control allow all
5581 request_header_access Content-Length allow all
5582 request_header_access Content-Type allow all
5583 request_header_access Date allow all
5584 request_header_access Host allow all
5585 request_header_access If-Modified-Since allow all
5586 request_header_access Pragma allow all
5587 request_header_access Accept allow all
5588 request_header_access Accept-Charset allow all
5589 request_header_access Accept-Encoding allow all
5590 request_header_access Accept-Language allow all
5591 request_header_access Connection allow all
5592 request_header_access All deny all
5594 HTTP reply headers are controlled with the reply_header_access directive.
5596 By default, all headers are allowed (no anonymizing is performed).
5599 NAME: reply_header_access
5600 IFDEF: USE_HTTP_VIOLATIONS
5601 TYPE: http_header_access
5602 LOC: Config.reply_header_access
5604 DEFAULT_DOC: No limits.
5606 Usage: reply_header_access header_name allow|deny [!]aclname ...
5608 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5609 this feature could make you liable for problems which it
5612 This option only applies to reply headers, i.e., from the
5613 server to the client.
5615 This is the same as request_header_access, but in the other
5616 direction. Please see request_header_access for detailed
5619 For example, to achieve the same behavior as the old
5620 'http_anonymizer standard' option, you should use:
5622 reply_header_access Server deny all
5623 reply_header_access WWW-Authenticate deny all
5624 reply_header_access Link deny all
5626 Or, to reproduce the old 'http_anonymizer paranoid' feature
5629 reply_header_access Allow allow all
5630 reply_header_access WWW-Authenticate allow all
5631 reply_header_access Proxy-Authenticate allow all
5632 reply_header_access Cache-Control allow all
5633 reply_header_access Content-Encoding allow all
5634 reply_header_access Content-Length allow all
5635 reply_header_access Content-Type allow all
5636 reply_header_access Date allow all
5637 reply_header_access Expires allow all
5638 reply_header_access Last-Modified allow all
5639 reply_header_access Location allow all
5640 reply_header_access Pragma allow all
5641 reply_header_access Content-Language allow all
5642 reply_header_access Retry-After allow all
5643 reply_header_access Title allow all
5644 reply_header_access Content-Disposition allow all
5645 reply_header_access Connection allow all
5646 reply_header_access All deny all
5648 HTTP request headers are controlled with the request_header_access directive.
5650 By default, all headers are allowed (no anonymizing is
5654 NAME: request_header_replace header_replace
5655 IFDEF: USE_HTTP_VIOLATIONS
5656 TYPE: http_header_replace
5657 LOC: Config.request_header_access
5660 Usage: request_header_replace header_name message
5661 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
5663 This option allows you to change the contents of headers
5664 denied with request_header_access above, by replacing them
5665 with some fixed string.
5667 This only applies to request headers, not reply headers.
5669 By default, headers are removed if denied.
5672 NAME: reply_header_replace
5673 IFDEF: USE_HTTP_VIOLATIONS
5674 TYPE: http_header_replace
5675 LOC: Config.reply_header_access
5678 Usage: reply_header_replace header_name message
5679 Example: reply_header_replace Server Foo/1.0
5681 This option allows you to change the contents of headers
5682 denied with reply_header_access above, by replacing them
5683 with some fixed string.
5685 This only applies to reply headers, not request headers.
5687 By default, headers are removed if denied.
5690 NAME: request_header_add
5691 TYPE: HeaderWithAclList
5692 LOC: Config.request_header_add
5695 Usage: request_header_add field-name field-value acl1 [acl2] ...
5696 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
5698 This option adds header fields to outgoing HTTP requests (i.e.,
5699 request headers sent by Squid to the next HTTP hop such as a
5700 cache peer or an origin server). The option has no effect during
5701 cache hit detection. The equivalent adaptation vectoring point
5702 in ICAP terminology is post-cache REQMOD.
5704 Field-name is a token specifying an HTTP header name. If a
5705 standard HTTP header name is used, Squid does not check whether
5706 the new header conflicts with any existing headers or violates
5707 HTTP rules. If the request to be modified already contains a
5708 field with the same name, the old field is preserved but the
5709 header field values are not merged.
5711 Field-value is either a token or a quoted string. If quoted
5712 string format is used, then the surrounding quotes are removed
5713 while escape sequences and %macros are processed.
5715 In theory, all of the logformat codes can be used as %macros.
5716 However, unlike logging (which happens at the very end of
5717 transaction lifetime), the transaction may not yet have enough
5718 information to expand a macro when the new header value is needed.
5719 And some information may already be available to Squid but not yet
5720 committed where the macro expansion code can access it (report
5721 such instances!). The macro will be expanded into a single dash
5722 ('-') in such cases. Not all macros have been tested.
5724 One or more Squid ACLs may be specified to restrict header
5725 injection to matching requests. As always in squid.conf, all
5726 ACLs in an option ACL list must be satisfied for the insertion
5727 to happen. The request_header_add option supports fast ACLs
5736 This option used to log custom information about the master
5737 transaction. For example, an admin may configure Squid to log
5738 which "user group" the transaction belongs to, where "user group"
5739 will be determined based on a set of ACLs and not [just]
5740 authentication information.
5741 Values of key/value pairs can be logged using %{key}note macros:
5743 note key value acl ...
5744 logformat myFormat ... %{key}note ...
5747 NAME: relaxed_header_parser
5748 COMMENT: on|off|warn
5750 LOC: Config.onoff.relaxed_header_parser
5753 In the default "on" setting Squid accepts certain forms
5754 of non-compliant HTTP messages where it is unambiguous
5755 what the sending application intended even if the message
5756 is not correctly formatted. The messages is then normalized
5757 to the correct form when forwarded by Squid.
5759 If set to "warn" then a warning will be emitted in cache.log
5760 each time such HTTP error is encountered.
5762 If set to "off" then such HTTP errors will cause the request
5763 or response to be rejected.
5766 NAME: collapsed_forwarding
5769 LOC: Config.onoff.collapsed_forwarding
5772 This option controls whether Squid is allowed to merge multiple
5773 potentially cachable requests for the same URI before Squid knows
5774 whether the response is going to be cachable.
5776 This feature is disabled by default: Enabling collapsed forwarding
5777 needlessly delays forwarding requests that look cachable (when they are
5778 collapsed) but then need to be forwarded individually anyway because
5779 they end up being for uncachable content. However, in some cases, such
5780 as accelleration of highly cachable content with periodic or groupped
5781 expiration times, the gains from collapsing [large volumes of
5782 simultenous refresh requests] outweigh losses from such delays.
5787 -----------------------------------------------------------------------------
5790 NAME: forward_timeout
5793 LOC: Config.Timeout.forward
5796 This parameter specifies how long Squid should at most attempt in
5797 finding a forwarding path for the request before giving up.
5800 NAME: connect_timeout
5803 LOC: Config.Timeout.connect
5806 This parameter specifies how long to wait for the TCP connect to
5807 the requested server or peer to complete before Squid should
5808 attempt to find another path where to forward the request.
5811 NAME: peer_connect_timeout
5814 LOC: Config.Timeout.peer_connect
5817 This parameter specifies how long to wait for a pending TCP
5818 connection to a peer cache. The default is 30 seconds. You
5819 may also set different timeout values for individual neighbors
5820 with the 'connect-timeout' option on a 'cache_peer' line.
5826 LOC: Config.Timeout.read
5829 The read_timeout is applied on server-side connections. After
5830 each successful read(), the timeout will be extended by this
5831 amount. If no data is read again after this amount of time,
5832 the request is aborted and logged with ERR_READ_TIMEOUT. The
5833 default is 15 minutes.
5839 LOC: Config.Timeout.write
5842 This timeout is tracked for all connections that have data
5843 available for writing and are waiting for the socket to become
5844 ready. After each successful write, the timeout is extended by
5845 the configured amount. If Squid has data to write but the
5846 connection is not ready for the configured duration, the
5847 transaction associated with the connection is terminated. The
5848 default is 15 minutes.
5851 NAME: request_timeout
5853 LOC: Config.Timeout.request
5856 How long to wait for complete HTTP request headers after initial
5857 connection establishment.
5860 NAME: client_idle_pconn_timeout persistent_request_timeout
5862 LOC: Config.Timeout.clientIdlePconn
5865 How long to wait for the next HTTP request on a persistent
5866 client connection after the previous request completes.
5869 NAME: client_lifetime
5872 LOC: Config.Timeout.lifetime
5875 The maximum amount of time a client (browser) is allowed to
5876 remain connected to the cache process. This protects the Cache
5877 from having a lot of sockets (and hence file descriptors) tied up
5878 in a CLOSE_WAIT state from remote clients that go away without
5879 properly shutting down (either because of a network failure or
5880 because of a poor client implementation). The default is one
5883 NOTE: The default value is intended to be much larger than any
5884 client would ever need to be connected to your cache. You
5885 should probably change client_lifetime only as a last resort.
5886 If you seem to have many client connections tying up
5887 filedescriptors, we recommend first tuning the read_timeout,
5888 request_timeout, persistent_request_timeout and quick_abort values.
5891 NAME: half_closed_clients
5893 LOC: Config.onoff.half_closed_clients
5896 Some clients may shutdown the sending side of their TCP
5897 connections, while leaving their receiving sides open. Sometimes,
5898 Squid can not tell the difference between a half-closed and a
5899 fully-closed TCP connection.
5901 By default, Squid will immediately close client connections when
5902 read(2) returns "no more data to read."
5904 Change this option to 'on' and Squid will keep open connections
5905 until a read(2) or write(2) on the socket returns an error.
5906 This may show some benefits for reverse proxies. But if not
5907 it is recommended to leave OFF.
5910 NAME: server_idle_pconn_timeout pconn_timeout
5912 LOC: Config.Timeout.serverIdlePconn
5915 Timeout for idle persistent connections to servers and other
5922 LOC: Ident::TheConfig.timeout
5925 Maximum time to wait for IDENT lookups to complete.
5927 If this is too high, and you enabled IDENT lookups from untrusted
5928 users, you might be susceptible to denial-of-service by having
5929 many ident requests going at once.
5932 NAME: shutdown_lifetime
5935 LOC: Config.shutdownLifetime
5938 When SIGTERM or SIGHUP is received, the cache is put into
5939 "shutdown pending" mode until all active sockets are closed.
5940 This value is the lifetime to set for all open descriptors
5941 during shutdown mode. Any active clients after this many
5942 seconds will receive a 'timeout' message.
5946 ADMINISTRATIVE PARAMETERS
5947 -----------------------------------------------------------------------------
5953 LOC: Config.adminEmail
5955 Email-address of local cache manager who will receive
5956 mail if the cache dies. The default is "webmaster".
5962 LOC: Config.EmailFrom
5964 From: email-address for mail sent when the cache dies.
5965 The default is to use 'squid@unique_hostname'.
5967 See also: unique_hostname directive.
5973 LOC: Config.EmailProgram
5975 Email program used to send mail if the cache dies.
5976 The default is "mail". The specified program must comply
5977 with the standard Unix mail syntax:
5978 mail-program recipient < mailfile
5980 Optional command line options can be specified.
5983 NAME: cache_effective_user
5985 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
5986 LOC: Config.effectiveUser
5988 If you start Squid as root, it will change its effective/real
5989 UID/GID to the user specified below. The default is to change
5990 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
5991 see also; cache_effective_group
5994 NAME: cache_effective_group
5997 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
5998 LOC: Config.effectiveGroup
6000 Squid sets the GID to the effective user's default group ID
6001 (taken from the password file) and supplementary group list
6002 from the groups membership.
6004 If you want Squid to run with a specific GID regardless of
6005 the group memberships of the effective user then set this
6006 to the group (or GID) you want Squid to run as. When set
6007 all other group privileges of the effective user are ignored
6008 and only this GID is effective. If Squid is not started as
6009 root the user starting Squid MUST be member of the specified
6012 This option is not recommended by the Squid Team.
6013 Our preference is for administrators to configure a secure
6014 user account for squid with UID/GID matching system policies.
6017 NAME: httpd_suppress_version_string
6021 LOC: Config.onoff.httpd_suppress_version_string
6023 Suppress Squid version string info in HTTP headers and HTML error pages.
6026 NAME: visible_hostname
6028 LOC: Config.visibleHostname
6030 DEFAULT_DOC: Automatically detect the system host name
6032 If you want to present a special hostname in error messages, etc,
6033 define this. Otherwise, the return value of gethostname()
6034 will be used. If you have multiple caches in a cluster and
6035 get errors about IP-forwarding you must set them to have individual
6036 names with this setting.
6039 NAME: unique_hostname
6041 LOC: Config.uniqueHostname
6043 DEFAULT_DOC: Copy the value from visible_hostname
6045 If you want to have multiple machines with the same
6046 'visible_hostname' you must give each machine a different
6047 'unique_hostname' so forwarding loops can be detected.
6050 NAME: hostname_aliases
6052 LOC: Config.hostnameAliases
6055 A list of other DNS names your cache has.
6063 Minimum umask which should be enforced while the proxy
6064 is running, in addition to the umask set at startup.
6066 For a traditional octal representation of umasks, start
6071 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6072 -----------------------------------------------------------------------------
6074 This section contains parameters for the (optional) cache
6075 announcement service. This service is provided to help
6076 cache administrators locate one another in order to join or
6077 create cache hierarchies.
6079 An 'announcement' message is sent (via UDP) to the registration
6080 service by Squid. By default, the announcement message is NOT
6081 SENT unless you enable it with 'announce_period' below.
6083 The announcement message includes your hostname, plus the
6084 following information from this configuration file:
6090 All current information is processed regularly and made
6091 available on the Web at http://www.ircache.net/Cache/Tracker/.
6094 NAME: announce_period
6096 LOC: Config.Announce.period
6098 DEFAULT_DOC: Announcement messages disabled.
6100 This is how frequently to send cache announcements.
6102 To enable announcing your cache, just set an announce period.
6105 announce_period 1 day
6110 DEFAULT: tracker.ircache.net
6111 LOC: Config.Announce.host
6113 Set the hostname where announce registration messages will be sent.
6115 See also announce_port and announce_file
6121 LOC: Config.Announce.file
6123 The contents of this file will be included in the announce
6124 registration messages.
6130 LOC: Config.Announce.port
6132 Set the port where announce registration messages will be sent.
6134 See also announce_host and announce_file
6138 HTTPD-ACCELERATOR OPTIONS
6139 -----------------------------------------------------------------------------
6142 NAME: httpd_accel_surrogate_id
6145 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
6146 LOC: Config.Accel.surrogate_id
6148 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
6149 need an identification token to allow control targeting. Because
6150 a farm of surrogates may all perform the same tasks, they may share
6151 an identification token.
6154 NAME: http_accel_surrogate_remote
6158 LOC: Config.onoff.surrogate_is_remote
6160 Remote surrogates (such as those in a CDN) honour the header
6161 "Surrogate-Control: no-store-remote".
6163 Set this to on to have squid behave as a remote surrogate.
6167 IFDEF: USE_SQUID_ESI
6168 COMMENT: libxml2|expat|custom
6170 LOC: ESIParser::Type
6173 ESI markup is not strictly XML compatible. The custom ESI parser
6174 will give higher performance, but cannot handle non ASCII character
6179 DELAY POOL PARAMETERS
6180 -----------------------------------------------------------------------------
6184 TYPE: delay_pool_count
6186 IFDEF: USE_DELAY_POOLS
6189 This represents the number of delay pools to be used. For example,
6190 if you have one class 2 delay pool and one class 3 delays pool, you
6191 have a total of 2 delay pools.
6193 See also delay_parameters, delay_class, delay_access for pool
6194 configuration details.
6198 TYPE: delay_pool_class
6200 IFDEF: USE_DELAY_POOLS
6203 This defines the class of each delay pool. There must be exactly one
6204 delay_class line for each delay pool. For example, to define two
6205 delay pools, one of class 2 and one of class 3, the settings above
6209 delay_pools 4 # 4 delay pools
6210 delay_class 1 2 # pool 1 is a class 2 pool
6211 delay_class 2 3 # pool 2 is a class 3 pool
6212 delay_class 3 4 # pool 3 is a class 4 pool
6213 delay_class 4 5 # pool 4 is a class 5 pool
6215 The delay pool classes are:
6217 class 1 Everything is limited by a single aggregate
6220 class 2 Everything is limited by a single aggregate
6221 bucket as well as an "individual" bucket chosen
6222 from bits 25 through 32 of the IPv4 address.
6224 class 3 Everything is limited by a single aggregate
6225 bucket as well as a "network" bucket chosen
6226 from bits 17 through 24 of the IP address and a
6227 "individual" bucket chosen from bits 17 through
6228 32 of the IPv4 address.
6230 class 4 Everything in a class 3 delay pool, with an
6231 additional limit on a per user basis. This
6232 only takes effect if the username is established
6233 in advance - by forcing authentication in your
6236 class 5 Requests are grouped according their tag (see
6237 external_acl's tag= reply).
6240 Each pool also requires a delay_parameters directive to configure the pool size
6241 and speed limits used whenever the pool is applied to a request. Along with
6242 a set of delay_access directives to determine when it is used.
6244 NOTE: If an IP address is a.b.c.d
6245 -> bits 25 through 32 are "d"
6246 -> bits 17 through 24 are "c"
6247 -> bits 17 through 32 are "c * 256 + d"
6249 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6250 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6252 This clause only supports fast acl types.
6253 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6255 See also delay_parameters and delay_access.
6259 TYPE: delay_pool_access
6261 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6262 IFDEF: USE_DELAY_POOLS
6265 This is used to determine which delay pool a request falls into.
6267 delay_access is sorted per pool and the matching starts with pool 1,
6268 then pool 2, ..., and finally pool N. The first delay pool where the
6269 request is allowed is selected for the request. If it does not allow
6270 the request to any pool then the request is not delayed (default).
6272 For example, if you want some_big_clients in delay
6273 pool 1 and lotsa_little_clients in delay pool 2:
6275 delay_access 1 allow some_big_clients
6276 delay_access 1 deny all
6277 delay_access 2 allow lotsa_little_clients
6278 delay_access 2 deny all
6279 delay_access 3 allow authenticated_clients
6281 See also delay_parameters and delay_class.
6285 NAME: delay_parameters
6286 TYPE: delay_pool_rates
6288 IFDEF: USE_DELAY_POOLS
6291 This defines the parameters for a delay pool. Each delay pool has
6292 a number of "buckets" associated with it, as explained in the
6293 description of delay_class.
6295 For a class 1 delay pool, the syntax is:
6297 delay_parameters pool aggregate
6299 For a class 2 delay pool:
6301 delay_parameters pool aggregate individual
6303 For a class 3 delay pool:
6305 delay_parameters pool aggregate network individual
6307 For a class 4 delay pool:
6309 delay_parameters pool aggregate network individual user
6311 For a class 5 delay pool:
6313 delay_parameters pool tagrate
6315 The option variables are:
6317 pool a pool number - ie, a number between 1 and the
6318 number specified in delay_pools as used in
6321 aggregate the speed limit parameters for the aggregate bucket
6324 individual the speed limit parameters for the individual
6325 buckets (class 2, 3).
6327 network the speed limit parameters for the network buckets
6330 user the speed limit parameters for the user buckets
6333 tagrate the speed limit parameters for the tag buckets
6336 A pair of delay parameters is written restore/maximum, where restore is
6337 the number of bytes (not bits - modem and network speeds are usually
6338 quoted in bits) per second placed into the bucket, and maximum is the
6339 maximum number of bytes which can be in the bucket at any time.
6341 There must be one delay_parameters line for each delay pool.
6344 For example, if delay pool number 1 is a class 2 delay pool as in the
6345 above example, and is being used to strictly limit each host to 64Kbit/sec
6346 (plus overheads), with no overall limit, the line is:
6348 delay_parameters 1 -1/-1 8000/8000
6350 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
6352 Note that the figure -1 is used to represent "unlimited".
6355 And, if delay pool number 2 is a class 3 delay pool as in the above
6356 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6357 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6358 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6359 to permit a decent web page to be downloaded at a decent speed
6360 (if the network is not being limited due to overuse) but slow down
6361 large downloads more significantly:
6363 delay_parameters 2 32000/32000 8000/8000 600/8000
6365 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
6366 8 x 8000 KByte/sec -> 64Kbit/sec.
6367 8 x 600 Byte/sec -> 4800bit/sec.
6370 Finally, for a class 4 delay pool as in the example - each user will
6371 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6373 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6376 See also delay_class and delay_access.
6380 NAME: delay_initial_bucket_level
6381 COMMENT: (percent, 0-100)
6384 IFDEF: USE_DELAY_POOLS
6385 LOC: Config.Delay.initial
6387 The initial bucket percentage is used to determine how much is put
6388 in each bucket when squid starts, is reconfigured, or first notices
6389 a host accessing it (in class 2 and class 3, individual hosts and
6390 networks only have buckets associated with them once they have been
6395 CLIENT DELAY POOL PARAMETERS
6396 -----------------------------------------------------------------------------
6399 NAME: client_delay_pools
6400 TYPE: client_delay_pool_count
6402 IFDEF: USE_DELAY_POOLS
6403 LOC: Config.ClientDelay
6405 This option specifies the number of client delay pools used. It must
6406 preceed other client_delay_* options.
6409 client_delay_pools 2
6411 See also client_delay_parameters and client_delay_access.
6414 NAME: client_delay_initial_bucket_level
6415 COMMENT: (percent, 0-no_limit)
6418 IFDEF: USE_DELAY_POOLS
6419 LOC: Config.ClientDelay.initial
6421 This option determines the initial bucket size as a percentage of
6422 max_bucket_size from client_delay_parameters. Buckets are created
6423 at the time of the "first" connection from the matching IP. Idle
6424 buckets are periodically deleted up.
6426 You can specify more than 100 percent but note that such "oversized"
6427 buckets are not refilled until their size goes down to max_bucket_size
6428 from client_delay_parameters.
6431 client_delay_initial_bucket_level 50
6434 NAME: client_delay_parameters
6435 TYPE: client_delay_pool_rates
6437 IFDEF: USE_DELAY_POOLS
6438 LOC: Config.ClientDelay
6441 This option configures client-side bandwidth limits using the
6444 client_delay_parameters pool speed_limit max_bucket_size
6446 pool is an integer ID used for client_delay_access matching.
6448 speed_limit is bytes added to the bucket per second.
6450 max_bucket_size is the maximum size of a bucket, enforced after any
6451 speed_limit additions.
6453 Please see the delay_parameters option for more information and
6457 client_delay_parameters 1 1024 2048
6458 client_delay_parameters 2 51200 16384
6460 See also client_delay_access.
6464 NAME: client_delay_access
6465 TYPE: client_delay_pool_access
6467 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6468 IFDEF: USE_DELAY_POOLS
6469 LOC: Config.ClientDelay
6471 This option determines the client-side delay pool for the
6474 client_delay_access pool_ID allow|deny acl_name
6476 All client_delay_access options are checked in their pool ID
6477 order, starting with pool 1. The first checked pool with allowed
6478 request is selected for the request. If no ACL matches or there
6479 are no client_delay_access options, the request bandwidth is not
6482 The ACL-selected pool is then used to find the
6483 client_delay_parameters for the request. Client-side pools are
6484 not used to aggregate clients. Clients are always aggregated
6485 based on their source IP addresses (one bucket per source IP).
6487 This clause only supports fast acl types.
6488 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6489 Additionally, only the client TCP connection details are available.
6490 ACLs testing HTTP properties will not work.
6492 Please see delay_access for more examples.
6495 client_delay_access 1 allow low_rate_network
6496 client_delay_access 2 allow vips_network
6499 See also client_delay_parameters and client_delay_pools.
6503 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6504 -----------------------------------------------------------------------------
6509 LOC: Config.Wccp.router
6511 DEFAULT_DOC: WCCP disabled.
6514 Use this option to define your WCCP ``home'' router for
6517 wccp_router supports a single WCCP(v1) router
6519 wccp2_router supports multiple WCCPv2 routers
6521 only one of the two may be used at the same time and defines
6522 which version of WCCP to use.
6526 TYPE: IpAddress_list
6527 LOC: Config.Wccp2.router
6529 DEFAULT_DOC: WCCPv2 disabled.
6532 Use this option to define your WCCP ``home'' router for
6535 wccp_router supports a single WCCP(v1) router
6537 wccp2_router supports multiple WCCPv2 routers
6539 only one of the two may be used at the same time and defines
6540 which version of WCCP to use.
6545 LOC: Config.Wccp.version
6549 This directive is only relevant if you need to set up WCCP(v1)
6550 to some very old and end-of-life Cisco routers. In all other
6551 setups it must be left unset or at the default setting.
6552 It defines an internal version in the WCCP(v1) protocol,
6553 with version 4 being the officially documented protocol.
6555 According to some users, Cisco IOS 11.2 and earlier only
6556 support WCCP version 3. If you're using that or an earlier
6557 version of IOS, you may need to change this value to 3, otherwise
6558 do not specify this parameter.
6561 NAME: wccp2_rebuild_wait
6563 LOC: Config.Wccp2.rebuildwait
6567 If this is enabled Squid will wait for the cache dir rebuild to finish
6568 before sending the first wccp2 HereIAm packet
6571 NAME: wccp2_forwarding_method
6573 LOC: Config.Wccp2.forwarding_method
6577 WCCP2 allows the setting of forwarding methods between the
6578 router/switch and the cache. Valid values are as follows:
6580 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6581 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6583 Currently (as of IOS 12.4) cisco routers only support GRE.
6584 Cisco switches only support the L2 redirect assignment method.
6587 NAME: wccp2_return_method
6589 LOC: Config.Wccp2.return_method
6593 WCCP2 allows the setting of return methods between the
6594 router/switch and the cache for packets that the cache
6595 decides not to handle. Valid values are as follows:
6597 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6598 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6600 Currently (as of IOS 12.4) cisco routers only support GRE.
6601 Cisco switches only support the L2 redirect assignment.
6603 If the "ip wccp redirect exclude in" command has been
6604 enabled on the cache interface, then it is still safe for
6605 the proxy server to use a l2 redirect method even if this
6606 option is set to GRE.
6609 NAME: wccp2_assignment_method
6611 LOC: Config.Wccp2.assignment_method
6615 WCCP2 allows the setting of methods to assign the WCCP hash
6616 Valid values are as follows:
6618 hash - Hash assignment
6619 mask - Mask assignment
6621 As a general rule, cisco routers support the hash assignment method
6622 and cisco switches support the mask assignment method.
6627 LOC: Config.Wccp2.info
6628 DEFAULT_IF_NONE: standard 0
6629 DEFAULT_DOC: Use the 'web-cache' standard service.
6632 WCCP2 allows for multiple traffic services. There are two
6633 types: "standard" and "dynamic". The standard type defines
6634 one service id - http (id 0). The dynamic service ids can be from
6635 51 to 255 inclusive. In order to use a dynamic service id
6636 one must define the type of traffic to be redirected; this is done
6637 using the wccp2_service_info option.
6639 The "standard" type does not require a wccp2_service_info option,
6640 just specifying the service id will suffice.
6642 MD5 service authentication can be enabled by adding
6643 "password=<password>" to the end of this service declaration.
6647 wccp2_service standard 0 # for the 'web-cache' standard service
6648 wccp2_service dynamic 80 # a dynamic service type which will be
6649 # fleshed out with subsequent options.
6650 wccp2_service standard 0 password=foo
6653 NAME: wccp2_service_info
6654 TYPE: wccp2_service_info
6655 LOC: Config.Wccp2.info
6659 Dynamic WCCPv2 services require further information to define the
6660 traffic you wish to have diverted.
6664 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
6665 priority=<priority> ports=<port>,<port>..
6667 The relevant WCCPv2 flags:
6668 + src_ip_hash, dst_ip_hash
6669 + source_port_hash, dst_port_hash
6670 + src_ip_alt_hash, dst_ip_alt_hash
6671 + src_port_alt_hash, dst_port_alt_hash
6674 The port list can be one to eight entries.
6678 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
6679 priority=240 ports=80
6681 Note: the service id must have been defined by a previous
6682 'wccp2_service dynamic <id>' entry.
6687 LOC: Config.Wccp2.weight
6691 Each cache server gets assigned a set of the destination
6692 hash proportional to their weight.
6697 LOC: Config.Wccp.address
6699 DEFAULT_DOC: Address selected by the operating system.
6702 Use this option if you require WCCPv2 to use a specific
6705 The default behavior is to not bind to any specific address.
6710 LOC: Config.Wccp2.address
6712 DEFAULT_DOC: Address selected by the operating system.
6715 Use this option if you require WCCP to use a specific
6718 The default behavior is to not bind to any specific address.
6722 PERSISTENT CONNECTION HANDLING
6723 -----------------------------------------------------------------------------
6725 Also see "pconn_timeout" in the TIMEOUTS section
6728 NAME: client_persistent_connections
6730 LOC: Config.onoff.client_pconns
6733 Persistent connection support for clients.
6734 Squid uses persistent connections (when allowed). You can use
6735 this option to disable persistent connections with clients.
6738 NAME: server_persistent_connections
6740 LOC: Config.onoff.server_pconns
6743 Persistent connection support for servers.
6744 Squid uses persistent connections (when allowed). You can use
6745 this option to disable persistent connections with servers.
6748 NAME: persistent_connection_after_error
6750 LOC: Config.onoff.error_pconns
6753 With this directive the use of persistent connections after
6754 HTTP errors can be disabled. Useful if you have clients
6755 who fail to handle errors on persistent connections proper.
6758 NAME: detect_broken_pconn
6760 LOC: Config.onoff.detect_broken_server_pconns
6763 Some servers have been found to incorrectly signal the use
6764 of HTTP/1.0 persistent connections even on replies not
6765 compatible, causing significant delays. This server problem
6766 has mostly been seen on redirects.
6768 By enabling this directive Squid attempts to detect such
6769 broken replies and automatically assume the reply is finished
6770 after 10 seconds timeout.
6774 CACHE DIGEST OPTIONS
6775 -----------------------------------------------------------------------------
6778 NAME: digest_generation
6779 IFDEF: USE_CACHE_DIGESTS
6781 LOC: Config.onoff.digest_generation
6784 This controls whether the server will generate a Cache Digest
6785 of its contents. By default, Cache Digest generation is
6786 enabled if Squid is compiled with --enable-cache-digests defined.
6789 NAME: digest_bits_per_entry
6790 IFDEF: USE_CACHE_DIGESTS
6792 LOC: Config.digest.bits_per_entry
6795 This is the number of bits of the server's Cache Digest which
6796 will be associated with the Digest entry for a given HTTP
6797 Method and URL (public key) combination. The default is 5.
6800 NAME: digest_rebuild_period
6801 IFDEF: USE_CACHE_DIGESTS
6804 LOC: Config.digest.rebuild_period
6807 This is the wait time between Cache Digest rebuilds.
6810 NAME: digest_rewrite_period
6812 IFDEF: USE_CACHE_DIGESTS
6814 LOC: Config.digest.rewrite_period
6817 This is the wait time between Cache Digest writes to
6821 NAME: digest_swapout_chunk_size
6824 IFDEF: USE_CACHE_DIGESTS
6825 LOC: Config.digest.swapout_chunk_size
6828 This is the number of bytes of the Cache Digest to write to
6829 disk at a time. It defaults to 4096 bytes (4KB), the Squid
6833 NAME: digest_rebuild_chunk_percentage
6834 COMMENT: (percent, 0-100)
6835 IFDEF: USE_CACHE_DIGESTS
6837 LOC: Config.digest.rebuild_chunk_percentage
6840 This is the percentage of the Cache Digest to be scanned at a
6841 time. By default it is set to 10% of the Cache Digest.
6846 -----------------------------------------------------------------------------
6851 LOC: Config.Port.snmp
6853 DEFAULT_DOC: SNMP disabled.
6856 The port number where Squid listens for SNMP requests. To enable
6857 SNMP support set this to a suitable port number. Port number
6858 3401 is often used for the Squid SNMP agent. By default it's
6859 set to "0" (disabled)
6867 LOC: Config.accessList.snmp
6869 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
6872 Allowing or denying access to the SNMP port.
6874 All access to the agent is denied by default.
6877 snmp_access allow|deny [!]aclname ...
6879 This clause only supports fast acl types.
6880 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6883 snmp_access allow snmppublic localhost
6884 snmp_access deny all
6887 NAME: snmp_incoming_address
6889 LOC: Config.Addrs.snmp_incoming
6891 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
6894 Just like 'udp_incoming_address', but for the SNMP port.
6896 snmp_incoming_address is used for the SNMP socket receiving
6897 messages from SNMP agents.
6899 The default snmp_incoming_address is to listen on all
6900 available network interfaces.
6903 NAME: snmp_outgoing_address
6905 LOC: Config.Addrs.snmp_outgoing
6907 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
6910 Just like 'udp_outgoing_address', but for the SNMP port.
6912 snmp_outgoing_address is used for SNMP packets returned to SNMP
6915 If snmp_outgoing_address is not set it will use the same socket
6916 as snmp_incoming_address. Only change this if you want to have
6917 SNMP replies sent using another address than where this Squid
6918 listens for SNMP queries.
6920 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
6921 the same value since they both use the same port.
6926 -----------------------------------------------------------------------------
6929 NAME: icp_port udp_port
6932 DEFAULT_DOC: ICP disabled.
6933 LOC: Config.Port.icp
6935 The port number where Squid sends and receives ICP queries to
6936 and from neighbor caches. The standard UDP port for ICP is 3130.
6939 icp_port @DEFAULT_ICP_PORT@
6946 DEFAULT_DOC: HTCP disabled.
6947 LOC: Config.Port.htcp
6949 The port number where Squid sends and receives HTCP queries to
6950 and from neighbor caches. To turn it on you want to set it to
6957 NAME: log_icp_queries
6961 LOC: Config.onoff.log_udp
6963 If set, ICP queries are logged to access.log. You may wish
6964 do disable this if your ICP load is VERY high to speed things
6965 up or to simplify log analysis.
6968 NAME: udp_incoming_address
6970 LOC:Config.Addrs.udp_incoming
6972 DEFAULT_DOC: Accept packets from all machine interfaces.
6974 udp_incoming_address is used for UDP packets received from other
6977 The default behavior is to not bind to any specific address.
6979 Only change this if you want to have all UDP queries received on
6980 a specific interface/address.
6982 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
6983 modules. Altering it will affect all of them in the same manner.
6985 see also; udp_outgoing_address
6987 NOTE, udp_incoming_address and udp_outgoing_address can not
6988 have the same value since they both use the same port.
6991 NAME: udp_outgoing_address
6993 LOC: Config.Addrs.udp_outgoing
6995 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
6997 udp_outgoing_address is used for UDP packets sent out to other
7000 The default behavior is to not bind to any specific address.
7002 Instead it will use the same socket as udp_incoming_address.
7003 Only change this if you want to have UDP queries sent using another
7004 address than where this Squid listens for UDP queries from other
7007 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7008 modules. Altering it will affect all of them in the same manner.
7010 see also; udp_incoming_address
7012 NOTE, udp_incoming_address and udp_outgoing_address can not
7013 have the same value since they both use the same port.
7020 LOC: Config.onoff.icp_hit_stale
7022 If you want to return ICP_HIT for stale cache objects, set this
7023 option to 'on'. If you have sibling relationships with caches
7024 in other administrative domains, this should be 'off'. If you only
7025 have sibling relationships with caches under your control,
7026 it is probably okay to set this to 'on'.
7027 If set to 'on', your siblings should use the option "allow-miss"
7028 on their cache_peer lines for connecting to you.
7031 NAME: minimum_direct_hops
7034 LOC: Config.minDirectHops
7036 If using the ICMP pinging stuff, do direct fetches for sites
7037 which are no more than this many hops away.
7040 NAME: minimum_direct_rtt
7044 LOC: Config.minDirectRtt
7046 If using the ICMP pinging stuff, do direct fetches for sites
7047 which are no more than this many rtt milliseconds away.
7053 LOC: Config.Netdb.low
7055 The low water mark for the ICMP measurement database.
7057 Note: high watermark controlled by netdb_high directive.
7059 These watermarks are counts, not percents. The defaults are
7060 (low) 900 and (high) 1000. When the high water mark is
7061 reached, database entries will be deleted until the low
7068 LOC: Config.Netdb.high
7070 The high water mark for the ICMP measurement database.
7072 Note: low watermark controlled by netdb_low directive.
7074 These watermarks are counts, not percents. The defaults are
7075 (low) 900 and (high) 1000. When the high water mark is
7076 reached, database entries will be deleted until the low
7080 NAME: netdb_ping_period
7082 LOC: Config.Netdb.period
7085 The minimum period for measuring a site. There will be at
7086 least this much delay between successive pings to the same
7087 network. The default is five minutes.
7094 LOC: Config.onoff.query_icmp
7096 If you want to ask your peers to include ICMP data in their ICP
7097 replies, enable this option.
7099 If your peer has configured Squid (during compilation) with
7100 '--enable-icmp' that peer will send ICMP pings to origin server
7101 sites of the URLs it receives. If you enable this option the
7102 ICP replies from that peer will include the ICMP data (if available).
7103 Then, when choosing a parent cache, Squid will choose the parent with
7104 the minimal RTT to the origin server. When this happens, the
7105 hierarchy field of the access.log will be
7106 "CLOSEST_PARENT_MISS". This option is off by default.
7109 NAME: test_reachability
7113 LOC: Config.onoff.test_reachability
7115 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
7116 instead of ICP_MISS if the target host is NOT in the ICMP
7117 database, or has a zero RTT.
7120 NAME: icp_query_timeout
7123 DEFAULT_DOC: Dynamic detection.
7125 LOC: Config.Timeout.icp_query
7127 Normally Squid will automatically determine an optimal ICP
7128 query timeout value based on the round-trip-time of recent ICP
7129 queries. If you want to override the value determined by
7130 Squid, set this 'icp_query_timeout' to a non-zero value. This
7131 value is specified in MILLISECONDS, so, to use a 2-second
7132 timeout (the old default), you would write:
7134 icp_query_timeout 2000
7137 NAME: maximum_icp_query_timeout
7141 LOC: Config.Timeout.icp_query_max
7143 Normally the ICP query timeout is determined dynamically. But
7144 sometimes it can lead to very large values (say 5 seconds).
7145 Use this option to put an upper limit on the dynamic timeout
7146 value. Do NOT use this option to always use a fixed (instead
7147 of a dynamic) timeout value. To set a fixed timeout see the
7148 'icp_query_timeout' directive.
7151 NAME: minimum_icp_query_timeout
7155 LOC: Config.Timeout.icp_query_min
7157 Normally the ICP query timeout is determined dynamically. But
7158 sometimes it can lead to very small timeouts, even lower than
7159 the normal latency variance on your link due to traffic.
7160 Use this option to put an lower limit on the dynamic timeout
7161 value. Do NOT use this option to always use a fixed (instead
7162 of a dynamic) timeout value. To set a fixed timeout see the
7163 'icp_query_timeout' directive.
7166 NAME: background_ping_rate
7170 LOC: Config.backgroundPingRate
7172 Controls how often the ICP pings are sent to siblings that
7173 have background-ping set.
7177 MULTICAST ICP OPTIONS
7178 -----------------------------------------------------------------------------
7183 LOC: Config.mcast_group_list
7186 This tag specifies a list of multicast groups which your server
7187 should join to receive multicasted ICP queries.
7189 NOTE! Be very careful what you put here! Be sure you
7190 understand the difference between an ICP _query_ and an ICP
7191 _reply_. This option is to be set only if you want to RECEIVE
7192 multicast queries. Do NOT set this option to SEND multicast
7193 ICP (use cache_peer for that). ICP replies are always sent via
7194 unicast, so this option does not affect whether or not you will
7195 receive replies from multicast group members.
7197 You must be very careful to NOT use a multicast address which
7198 is already in use by another group of caches.
7200 If you are unsure about multicast, please read the Multicast
7201 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7203 Usage: mcast_groups 239.128.16.128 224.0.1.20
7205 By default, Squid doesn't listen on any multicast groups.
7208 NAME: mcast_miss_addr
7209 IFDEF: MULTICAST_MISS_STREAM
7211 LOC: Config.mcast_miss.addr
7213 DEFAULT_DOC: disabled.
7215 If you enable this option, every "cache miss" URL will
7216 be sent out on the specified multicast address.
7218 Do not enable this option unless you are are absolutely
7219 certain you understand what you are doing.
7222 NAME: mcast_miss_ttl
7223 IFDEF: MULTICAST_MISS_STREAM
7225 LOC: Config.mcast_miss.ttl
7228 This is the time-to-live value for packets multicasted
7229 when multicasting off cache miss URLs is enabled. By
7230 default this is set to 'site scope', i.e. 16.
7233 NAME: mcast_miss_port
7234 IFDEF: MULTICAST_MISS_STREAM
7236 LOC: Config.mcast_miss.port
7239 This is the port number to be used in conjunction with
7243 NAME: mcast_miss_encode_key
7244 IFDEF: MULTICAST_MISS_STREAM
7246 LOC: Config.mcast_miss.encode_key
7247 DEFAULT: XXXXXXXXXXXXXXXX
7249 The URLs that are sent in the multicast miss stream are
7250 encrypted. This is the encryption key.
7253 NAME: mcast_icp_query_timeout
7257 LOC: Config.Timeout.mcast_icp_query
7259 For multicast peers, Squid regularly sends out ICP "probes" to
7260 count how many other peers are listening on the given multicast
7261 address. This value specifies how long Squid should wait to
7262 count all the replies. The default is 2000 msec, or 2
7267 INTERNAL ICON OPTIONS
7268 -----------------------------------------------------------------------------
7271 NAME: icon_directory
7273 LOC: Config.icons.directory
7274 DEFAULT: @DEFAULT_ICON_DIR@
7276 Where the icons are stored. These are normally kept in
7280 NAME: global_internal_static
7282 LOC: Config.onoff.global_internal_static
7285 This directive controls is Squid should intercept all requests for
7286 /squid-internal-static/ no matter which host the URL is requesting
7287 (default on setting), or if nothing special should be done for
7288 such URLs (off setting). The purpose of this directive is to make
7289 icons etc work better in complex cache hierarchies where it may
7290 not always be possible for all corners in the cache mesh to reach
7291 the server generating a directory listing.
7294 NAME: short_icon_urls
7296 LOC: Config.icons.use_short_names
7299 If this is enabled Squid will use short URLs for icons.
7300 If disabled it will revert to the old behavior of including
7301 it's own name and port in the URL.
7303 If you run a complex cache hierarchy with a mix of Squid and
7304 other proxies you may need to disable this directive.
7309 -----------------------------------------------------------------------------
7312 NAME: error_directory
7314 LOC: Config.errorDirectory
7316 DEFAULT_DOC: Send error pages in the clients preferred language
7318 If you wish to create your own versions of the default
7319 error files to customize them to suit your company copy
7320 the error/template files to another directory and point
7323 WARNING: This option will disable multi-language support
7324 on error pages if used.
7326 The squid developers are interested in making squid available in
7327 a wide variety of languages. If you are making translations for a
7328 language that Squid does not currently provide please consider
7329 contributing your translation back to the project.
7330 http://wiki.squid-cache.org/Translations
7332 The squid developers working on translations are happy to supply drop-in
7333 translated error files in exchange for any new language contributions.
7336 NAME: error_default_language
7337 IFDEF: USE_ERR_LOCALES
7339 LOC: Config.errorDefaultLanguage
7341 DEFAULT_DOC: Generate English language pages.
7343 Set the default language which squid will send error pages in
7344 if no existing translation matches the clients language
7347 If unset (default) generic English will be used.
7349 The squid developers are interested in making squid available in
7350 a wide variety of languages. If you are interested in making
7351 translations for any language see the squid wiki for details.
7352 http://wiki.squid-cache.org/Translations
7355 NAME: error_log_languages
7356 IFDEF: USE_ERR_LOCALES
7358 LOC: Config.errorLogMissingLanguages
7361 Log to cache.log what languages users are attempting to
7362 auto-negotiate for translations.
7364 Successful negotiations are not logged. Only failures
7365 have meaning to indicate that Squid may need an upgrade
7366 of its error page translations.
7369 NAME: err_page_stylesheet
7371 LOC: Config.errorStylesheet
7372 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7374 CSS Stylesheet to pattern the display of Squid default error pages.
7376 For information on CSS see http://www.w3.org/Style/CSS/
7381 LOC: Config.errHtmlText
7384 HTML text to include in error messages. Make this a "mailto"
7385 URL to your admin address, or maybe just a link to your
7386 organizations Web page.
7388 To include this in your error messages, you must rewrite
7389 the error template files (found in the "errors" directory).
7390 Wherever you want the 'err_html_text' line to appear,
7391 insert a %L tag in the error template file.
7394 NAME: email_err_data
7397 LOC: Config.onoff.emailErrData
7400 If enabled, information about the occurred error will be
7401 included in the mailto links of the ERR pages (if %W is set)
7402 so that the email body contains the data.
7403 Syntax is <A HREF="mailto:%w%W">%w</A>
7408 LOC: Config.denyInfoList
7411 Usage: deny_info err_page_name acl
7412 or deny_info http://... acl
7413 or deny_info TCP_RESET acl
7415 This can be used to return a ERR_ page for requests which
7416 do not pass the 'http_access' rules. Squid remembers the last
7417 acl it evaluated in http_access, and if a 'deny_info' line exists
7418 for that ACL Squid returns a corresponding error page.
7420 The acl is typically the last acl on the http_access deny line which
7421 denied access. The exceptions to this rule are:
7422 - When Squid needs to request authentication credentials. It's then
7423 the first authentication related acl encountered
7424 - When none of the http_access lines matches. It's then the last
7425 acl processed on the last http_access line.
7426 - When the decision to deny access was made by an adaptation service,
7427 the acl name is the corresponding eCAP or ICAP service_name.
7429 NP: If providing your own custom error pages with error_directory
7430 you may also specify them by your custom file name:
7431 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7433 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7434 may be specified by prefixing the file name with the code and a colon.
7435 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7437 Alternatively you can tell Squid to reset the TCP connection
7438 by specifying TCP_RESET.
7440 Or you can specify an error URL or URL pattern. The browsers will
7441 get redirected to the specified URL after formatting tags have
7442 been replaced. Redirect will be done with 302 or 307 according to
7443 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7444 the URL. e.g. 303:http://example.com/
7447 %a - username (if available. Password NOT included)
7450 %E - Error description
7452 %H - Request domain name
7453 %i - Client IP Address
7455 %o - Message result from external ACL helper
7456 %p - Request Port number
7457 %P - Request Protocol name
7458 %R - Request URL path
7459 %T - Timestamp in RFC 1123 format
7460 %U - Full canonical URL from client
7461 (HTTPS URLs terminate with *)
7462 %u - Full canonical URL from client
7463 %w - Admin email from squid.conf
7465 %% - Literal percent (%) code
7470 OPTIONS INFLUENCING REQUEST FORWARDING
7471 -----------------------------------------------------------------------------
7474 NAME: nonhierarchical_direct
7476 LOC: Config.onoff.nonhierarchical_direct
7479 By default, Squid will send any non-hierarchical requests
7480 (matching hierarchy_stoplist or not cacheable request type) direct
7483 When this is set to "off", Squid will prefer to send these
7484 requests to parents.
7486 Note that in most configurations, by turning this off you will only
7487 add latency to these request without any improvement in global hit
7490 This option only sets a preference. If the parent is unavailable a
7491 direct connection to the origin server may still be attempted. To
7492 completely prevent direct connections use never_direct.
7497 LOC: Config.onoff.prefer_direct
7500 Normally Squid tries to use parents for most requests. If you for some
7501 reason like it to first try going direct and only use a parent if
7502 going direct fails set this to on.
7504 By combining nonhierarchical_direct off and prefer_direct on you
7505 can set up Squid to use a parent as a backup path if going direct
7508 Note: If you want Squid to use parents for all requests see
7509 the never_direct directive. prefer_direct only modifies how Squid
7510 acts on cacheable requests.
7513 NAME: cache_miss_revalidate
7517 LOC: Config.onoff.cache_miss_revalidate
7519 RFC 7232 defines a conditional request mechanism to prevent
7520 response objects being unnecessarily transferred over the network.
7521 If that mechanism is used by the client and a cache MISS occurs
7522 it can prevent new cache entries being created.
7524 This option determines whether Squid on cache MISS will pass the
7525 client revalidation request to the server or tries to fetch new
7526 content for caching. It can be useful while the cache is mostly
7527 empty to more quickly have the cache populated by generating
7528 non-conditional GETs.
7530 When set to 'on' (default), Squid will pass all client If-* headers
7531 to the server. This permits server responses without a cacheable
7532 payload to be delivered and on MISS no new cache entry is created.
7534 When set to 'off' and if the request is cacheable, Squid will
7535 remove the clients If-Modified-Since and If-None-Match headers from
7536 the request sent to the server. This requests a 200 status response
7537 from the server to create a new cache entry with.
7542 LOC: Config.accessList.AlwaysDirect
7544 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7546 Usage: always_direct allow|deny [!]aclname ...
7548 Here you can use ACL elements to specify requests which should
7549 ALWAYS be forwarded by Squid to the origin servers without using
7550 any peers. For example, to always directly forward requests for
7551 local servers ignoring any parents or siblings you may have use
7554 acl local-servers dstdomain my.domain.net
7555 always_direct allow local-servers
7557 To always forward FTP requests directly, use
7560 always_direct allow FTP
7562 NOTE: There is a similar, but opposite option named
7563 'never_direct'. You need to be aware that "always_direct deny
7564 foo" is NOT the same thing as "never_direct allow foo". You
7565 may need to use a deny rule to exclude a more-specific case of
7566 some other rule. Example:
7568 acl local-external dstdomain external.foo.net
7569 acl local-servers dstdomain .foo.net
7570 always_direct deny local-external
7571 always_direct allow local-servers
7573 NOTE: If your goal is to make the client forward the request
7574 directly to the origin server bypassing Squid then this needs
7575 to be done in the client configuration. Squid configuration
7576 can only tell Squid how Squid should fetch the object.
7578 NOTE: This directive is not related to caching. The replies
7579 is cached as usual even if you use always_direct. To not cache
7580 the replies see the 'cache' directive.
7582 This clause supports both fast and slow acl types.
7583 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7588 LOC: Config.accessList.NeverDirect
7590 DEFAULT_DOC: Allow DNS results to be used for this request.
7592 Usage: never_direct allow|deny [!]aclname ...
7594 never_direct is the opposite of always_direct. Please read
7595 the description for always_direct if you have not already.
7597 With 'never_direct' you can use ACL elements to specify
7598 requests which should NEVER be forwarded directly to origin
7599 servers. For example, to force the use of a proxy for all
7600 requests, except those in your local domain use something like:
7602 acl local-servers dstdomain .foo.net
7603 never_direct deny local-servers
7604 never_direct allow all
7606 or if Squid is inside a firewall and there are local intranet
7607 servers inside the firewall use something like:
7609 acl local-intranet dstdomain .foo.net
7610 acl local-external dstdomain external.foo.net
7611 always_direct deny local-external
7612 always_direct allow local-intranet
7613 never_direct allow all
7615 This clause supports both fast and slow acl types.
7616 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7620 ADVANCED NETWORKING OPTIONS
7621 -----------------------------------------------------------------------------
7624 NAME: incoming_udp_average incoming_icp_average
7627 LOC: Config.comm_incoming.udp.average
7629 Heavy voodoo here. I can't even believe you are reading this.
7630 Are you crazy? Don't even think about adjusting these unless
7631 you understand the algorithms in comm_select.c first!
7634 NAME: incoming_tcp_average incoming_http_average
7637 LOC: Config.comm_incoming.tcp.average
7639 Heavy voodoo here. I can't even believe you are reading this.
7640 Are you crazy? Don't even think about adjusting these unless
7641 you understand the algorithms in comm_select.c first!
7644 NAME: incoming_dns_average
7647 LOC: Config.comm_incoming.dns.average
7649 Heavy voodoo here. I can't even believe you are reading this.
7650 Are you crazy? Don't even think about adjusting these unless
7651 you understand the algorithms in comm_select.c first!
7654 NAME: min_udp_poll_cnt min_icp_poll_cnt
7657 LOC: Config.comm_incoming.udp.min_poll
7659 Heavy voodoo here. I can't even believe you are reading this.
7660 Are you crazy? Don't even think about adjusting these unless
7661 you understand the algorithms in comm_select.c first!
7664 NAME: min_dns_poll_cnt
7667 LOC: Config.comm_incoming.dns.min_poll
7669 Heavy voodoo here. I can't even believe you are reading this.
7670 Are you crazy? Don't even think about adjusting these unless
7671 you understand the algorithms in comm_select.c first!
7674 NAME: min_tcp_poll_cnt min_http_poll_cnt
7677 LOC: Config.comm_incoming.tcp.min_poll
7679 Heavy voodoo here. I can't even believe you are reading this.
7680 Are you crazy? Don't even think about adjusting these unless
7681 you understand the algorithms in comm_select.c first!
7687 LOC: Config.accept_filter
7691 The name of an accept(2) filter to install on Squid's
7692 listen socket(s). This feature is perhaps specific to
7693 FreeBSD and requires support in the kernel.
7695 The 'httpready' filter delays delivering new connections
7696 to Squid until a full HTTP request has been received.
7697 See the accf_http(9) man page for details.
7699 The 'dataready' filter delays delivering new connections
7700 to Squid until there is some data to process.
7701 See the accf_dataready(9) man page for details.
7705 The 'data' filter delays delivering of new connections
7706 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
7707 You may optionally specify a number of seconds to wait by
7708 'data=N' where N is the number of seconds. Defaults to 30
7709 if not specified. See the tcp(7) man page for details.
7712 accept_filter httpready
7717 NAME: client_ip_max_connections
7719 LOC: Config.client_ip_max_connections
7721 DEFAULT_DOC: No limit.
7723 Set an absolute limit on the number of connections a single
7724 client IP can use. Any more than this and Squid will begin to drop
7725 new connections from the client until it closes some links.
7727 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
7728 connections from the client. For finer control use the ACL access controls.
7730 Requires client_db to be enabled (the default).
7732 WARNING: This may noticably slow down traffic received via external proxies
7733 or NAT devices and cause them to rebound error messages back to their clients.
7736 NAME: tcp_recv_bufsize
7740 DEFAULT_DOC: Use operating system TCP defaults.
7741 LOC: Config.tcpRcvBufsz
7743 Size of receive buffer to set for TCP sockets. Probably just
7744 as easy to change your kernel's default.
7745 Omit from squid.conf to use the default buffer size.
7750 -----------------------------------------------------------------------------
7757 LOC: Adaptation::Icap::TheConfig.onoff
7760 If you want to enable the ICAP module support, set this to on.
7763 NAME: icap_connect_timeout
7766 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
7769 This parameter specifies how long to wait for the TCP connect to
7770 the requested ICAP server to complete before giving up and either
7771 terminating the HTTP transaction or bypassing the failure.
7773 The default for optional services is peer_connect_timeout.
7774 The default for essential services is connect_timeout.
7775 If this option is explicitly set, its value applies to all services.
7778 NAME: icap_io_timeout
7782 DEFAULT_DOC: Use read_timeout.
7783 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
7786 This parameter specifies how long to wait for an I/O activity on
7787 an established, active ICAP connection before giving up and
7788 either terminating the HTTP transaction or bypassing the
7792 NAME: icap_service_failure_limit
7793 COMMENT: limit [in memory-depth time-units]
7794 TYPE: icap_service_failure_limit
7796 LOC: Adaptation::Icap::TheConfig
7799 The limit specifies the number of failures that Squid tolerates
7800 when establishing a new TCP connection with an ICAP service. If
7801 the number of failures exceeds the limit, the ICAP service is
7802 not used for new ICAP requests until it is time to refresh its
7805 A negative value disables the limit. Without the limit, an ICAP
7806 service will not be considered down due to connectivity failures
7807 between ICAP OPTIONS requests.
7809 Squid forgets ICAP service failures older than the specified
7810 value of memory-depth. The memory fading algorithm
7811 is approximate because Squid does not remember individual
7812 errors but groups them instead, splitting the option
7813 value into ten time slots of equal length.
7815 When memory-depth is 0 and by default this option has no
7816 effect on service failure expiration.
7818 Squid always forgets failures when updating service settings
7819 using an ICAP OPTIONS transaction, regardless of this option
7823 # suspend service usage after 10 failures in 5 seconds:
7824 icap_service_failure_limit 10 in 5 seconds
7827 NAME: icap_service_revival_delay
7830 LOC: Adaptation::Icap::TheConfig.service_revival_delay
7833 The delay specifies the number of seconds to wait after an ICAP
7834 OPTIONS request failure before requesting the options again. The
7835 failed ICAP service is considered "down" until fresh OPTIONS are
7838 The actual delay cannot be smaller than the hardcoded minimum
7839 delay of 30 seconds.
7842 NAME: icap_preview_enable
7846 LOC: Adaptation::Icap::TheConfig.preview_enable
7849 The ICAP Preview feature allows the ICAP server to handle the
7850 HTTP message by looking only at the beginning of the message body
7851 or even without receiving the body at all. In some environments,
7852 previews greatly speedup ICAP processing.
7854 During an ICAP OPTIONS transaction, the server may tell Squid what
7855 HTTP messages should be previewed and how big the preview should be.
7856 Squid will not use Preview if the server did not request one.
7858 To disable ICAP Preview for all ICAP services, regardless of
7859 individual ICAP server OPTIONS responses, set this option to "off".
7861 icap_preview_enable off
7864 NAME: icap_preview_size
7867 LOC: Adaptation::Icap::TheConfig.preview_size
7869 DEFAULT_DOC: No preview sent.
7871 The default size of preview data to be sent to the ICAP server.
7872 This value might be overwritten on a per server basis by OPTIONS requests.
7875 NAME: icap_206_enable
7879 LOC: Adaptation::Icap::TheConfig.allow206_enable
7882 206 (Partial Content) responses is an ICAP extension that allows the
7883 ICAP agents to optionally combine adapted and original HTTP message
7884 content. The decision to combine is postponed until the end of the
7885 ICAP response. Squid supports Partial Content extension by default.
7887 Activation of the Partial Content extension is negotiated with each
7888 ICAP service during OPTIONS exchange. Most ICAP servers should handle
7889 negotation correctly even if they do not support the extension, but
7890 some might fail. To disable Partial Content support for all ICAP
7891 services and to avoid any negotiation, set this option to "off".
7897 NAME: icap_default_options_ttl
7900 LOC: Adaptation::Icap::TheConfig.default_options_ttl
7903 The default TTL value for ICAP OPTIONS responses that don't have
7904 an Options-TTL header.
7907 NAME: icap_persistent_connections
7911 LOC: Adaptation::Icap::TheConfig.reuse_connections
7914 Whether or not Squid should use persistent connections to
7918 NAME: adaptation_send_client_ip icap_send_client_ip
7920 IFDEF: USE_ADAPTATION
7922 LOC: Adaptation::Config::send_client_ip
7925 If enabled, Squid shares HTTP client IP information with adaptation
7926 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
7927 For eCAP, Squid sets the libecap::metaClientIp transaction option.
7929 See also: adaptation_uses_indirect_client
7932 NAME: adaptation_send_username icap_send_client_username
7934 IFDEF: USE_ADAPTATION
7936 LOC: Adaptation::Config::send_username
7939 This sends authenticated HTTP client username (if available) to
7940 the adaptation service.
7942 For ICAP, the username value is encoded based on the
7943 icap_client_username_encode option and is sent using the header
7944 specified by the icap_client_username_header option.
7947 NAME: icap_client_username_header
7950 LOC: Adaptation::Icap::TheConfig.client_username_header
7951 DEFAULT: X-Client-Username
7953 ICAP request header name to use for adaptation_send_username.
7956 NAME: icap_client_username_encode
7960 LOC: Adaptation::Icap::TheConfig.client_username_encode
7963 Whether to base64 encode the authenticated client username.
7967 TYPE: icap_service_type
7969 LOC: Adaptation::Icap::TheConfig
7972 Defines a single ICAP service using the following format:
7974 icap_service id vectoring_point uri [option ...]
7977 an opaque identifier or name which is used to direct traffic to
7978 this specific service. Must be unique among all adaptation
7979 services in squid.conf.
7981 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7982 This specifies at which point of transaction processing the
7983 ICAP service should be activated. *_postcache vectoring points
7984 are not yet supported.
7986 uri: icap://servername:port/servicepath
7987 ICAP server and service location.
7989 ICAP does not allow a single service to handle both REQMOD and RESPMOD
7990 transactions. Squid does not enforce that requirement. You can specify
7991 services with the same service_url and different vectoring_points. You
7992 can even specify multiple identical services as long as their
7993 service_names differ.
7995 To activate a service, use the adaptation_access directive. To group
7996 services, use adaptation_service_chain and adaptation_service_set.
7998 Service options are separated by white space. ICAP services support
7999 the following name=value options:
8002 If set to 'on' or '1', the ICAP service is treated as
8003 optional. If the service cannot be reached or malfunctions,
8004 Squid will try to ignore any errors and process the message as
8005 if the service was not enabled. No all ICAP errors can be
8006 bypassed. If set to 0, the ICAP service is treated as
8007 essential and all ICAP errors will result in an error page
8008 returned to the HTTP client.
8010 Bypass is off by default: services are treated as essential.
8013 If set to 'on' or '1', the ICAP service is allowed to
8014 dynamically change the current message adaptation plan by
8015 returning a chain of services to be used next. The services
8016 are specified using the X-Next-Services ICAP response header
8017 value, formatted as a comma-separated list of service names.
8018 Each named service should be configured in squid.conf. Other
8019 services are ignored. An empty X-Next-Services value results
8020 in an empty plan which ends the current adaptation.
8022 Dynamic adaptation plan may cross or cover multiple supported
8023 vectoring points in their natural processing order.
8025 Routing is not allowed by default: the ICAP X-Next-Services
8026 response header is ignored.
8029 Only has effect on split-stack systems. The default on those systems
8030 is to use IPv4-only connections. When set to 'on' this option will
8031 make Squid use IPv6-only connections to contact this ICAP service.
8033 on-overload=block|bypass|wait|force
8034 If the service Max-Connections limit has been reached, do
8035 one of the following for each new ICAP transaction:
8036 * block: send an HTTP error response to the client
8037 * bypass: ignore the "over-connected" ICAP service
8038 * wait: wait (in a FIFO queue) for an ICAP connection slot
8039 * force: proceed, ignoring the Max-Connections limit
8041 In SMP mode with N workers, each worker assumes the service
8042 connection limit is Max-Connections/N, even though not all
8043 workers may use a given service.
8045 The default value is "bypass" if service is bypassable,
8046 otherwise it is set to "wait".
8050 Use the given number as the Max-Connections limit, regardless
8051 of the Max-Connections value given by the service, if any.
8053 Older icap_service format without optional named parameters is
8054 deprecated but supported for backward compatibility.
8057 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
8058 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
8062 TYPE: icap_class_type
8067 This deprecated option was documented to define an ICAP service
8068 chain, even though it actually defined a set of similar, redundant
8069 services, and the chains were not supported.
8071 To define a set of redundant services, please use the
8072 adaptation_service_set directive. For service chains, use
8073 adaptation_service_chain.
8077 TYPE: icap_access_type
8082 This option is deprecated. Please use adaptation_access, which
8083 has the same ICAP functionality, but comes with better
8084 documentation, and eCAP support.
8089 -----------------------------------------------------------------------------
8096 LOC: Adaptation::Ecap::TheConfig.onoff
8099 Controls whether eCAP support is enabled.
8103 TYPE: ecap_service_type
8105 LOC: Adaptation::Ecap::TheConfig
8108 Defines a single eCAP service
8110 ecap_service id vectoring_point uri [option ...]
8113 an opaque identifier or name which is used to direct traffic to
8114 this specific service. Must be unique among all adaptation
8115 services in squid.conf.
8117 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8118 This specifies at which point of transaction processing the
8119 eCAP service should be activated. *_postcache vectoring points
8120 are not yet supported.
8122 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
8123 Squid uses the eCAP service URI to match this configuration
8124 line with one of the dynamically loaded services. Each loaded
8125 eCAP service must have a unique URI. Obtain the right URI from
8126 the service provider.
8128 To activate a service, use the adaptation_access directive. To group
8129 services, use adaptation_service_chain and adaptation_service_set.
8131 Service options are separated by white space. eCAP services support
8132 the following name=value options:
8135 If set to 'on' or '1', the eCAP service is treated as optional.
8136 If the service cannot be reached or malfunctions, Squid will try
8137 to ignore any errors and process the message as if the service
8138 was not enabled. No all eCAP errors can be bypassed.
8139 If set to 'off' or '0', the eCAP service is treated as essential
8140 and all eCAP errors will result in an error page returned to the
8143 Bypass is off by default: services are treated as essential.
8146 If set to 'on' or '1', the eCAP service is allowed to
8147 dynamically change the current message adaptation plan by
8148 returning a chain of services to be used next.
8150 Dynamic adaptation plan may cross or cover multiple supported
8151 vectoring points in their natural processing order.
8153 Routing is not allowed by default.
8155 Older ecap_service format without optional named parameters is
8156 deprecated but supported for backward compatibility.
8160 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
8161 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
8164 NAME: loadable_modules
8166 IFDEF: USE_LOADABLE_MODULES
8167 LOC: Config.loadable_module_names
8170 Instructs Squid to load the specified dynamic module(s) or activate
8171 preloaded module(s).
8173 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
8177 MESSAGE ADAPTATION OPTIONS
8178 -----------------------------------------------------------------------------
8181 NAME: adaptation_service_set
8182 TYPE: adaptation_service_set_type
8183 IFDEF: USE_ADAPTATION
8188 Configures an ordered set of similar, redundant services. This is
8189 useful when hot standby or backup adaptation servers are available.
8191 adaptation_service_set set_name service_name1 service_name2 ...
8193 The named services are used in the set declaration order. The first
8194 applicable adaptation service from the set is used first. The next
8195 applicable service is tried if and only if the transaction with the
8196 previous service fails and the message waiting to be adapted is still
8199 When adaptation starts, broken services are ignored as if they were
8200 not a part of the set. A broken service is a down optional service.
8202 The services in a set must be attached to the same vectoring point
8203 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8205 If all services in a set are optional then adaptation failures are
8206 bypassable. If all services in the set are essential, then a
8207 transaction failure with one service may still be retried using
8208 another service from the set, but when all services fail, the master
8209 transaction fails as well.
8211 A set may contain a mix of optional and essential services, but that
8212 is likely to lead to surprising results because broken services become
8213 ignored (see above), making previously bypassable failures fatal.
8214 Technically, it is the bypassability of the last failed service that
8217 See also: adaptation_access adaptation_service_chain
8220 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
8221 adaptation service_set svcLogger loggerLocal loggerRemote
8224 NAME: adaptation_service_chain
8225 TYPE: adaptation_service_chain_type
8226 IFDEF: USE_ADAPTATION
8231 Configures a list of complementary services that will be applied
8232 one-by-one, forming an adaptation chain or pipeline. This is useful
8233 when Squid must perform different adaptations on the same message.
8235 adaptation_service_chain chain_name service_name1 svc_name2 ...
8237 The named services are used in the chain declaration order. The first
8238 applicable adaptation service from the chain is used first. The next
8239 applicable service is applied to the successful adaptation results of
8240 the previous service in the chain.
8242 When adaptation starts, broken services are ignored as if they were
8243 not a part of the chain. A broken service is a down optional service.
8245 Request satisfaction terminates the adaptation chain because Squid
8246 does not currently allow declaration of RESPMOD services at the
8247 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8249 The services in a chain must be attached to the same vectoring point
8250 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8252 A chain may contain a mix of optional and essential services. If an
8253 essential adaptation fails (or the failure cannot be bypassed for
8254 other reasons), the master transaction fails. Otherwise, the failure
8255 is bypassed as if the failed adaptation service was not in the chain.
8257 See also: adaptation_access adaptation_service_set
8260 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8263 NAME: adaptation_access
8264 TYPE: adaptation_access_type
8265 IFDEF: USE_ADAPTATION
8268 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8270 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8272 adaptation_access service_name allow|deny [!]aclname...
8273 adaptation_access set_name allow|deny [!]aclname...
8275 At each supported vectoring point, the adaptation_access
8276 statements are processed in the order they appear in this
8277 configuration file. Statements pointing to the following services
8278 are ignored (i.e., skipped without checking their ACL):
8280 - services serving different vectoring points
8281 - "broken-but-bypassable" services
8282 - "up" services configured to ignore such transactions
8283 (e.g., based on the ICAP Transfer-Ignore header).
8285 When a set_name is used, all services in the set are checked
8286 using the same rules, to find the first applicable one. See
8287 adaptation_service_set for details.
8289 If an access list is checked and there is a match, the
8290 processing stops: For an "allow" rule, the corresponding
8291 adaptation service is used for the transaction. For a "deny"
8292 rule, no adaptation service is activated.
8294 It is currently not possible to apply more than one adaptation
8295 service at the same vectoring point to the same HTTP transaction.
8297 See also: icap_service and ecap_service
8300 adaptation_access service_1 allow all
8303 NAME: adaptation_service_iteration_limit
8305 IFDEF: USE_ADAPTATION
8306 LOC: Adaptation::Config::service_iteration_limit
8309 Limits the number of iterations allowed when applying adaptation
8310 services to a message. If your longest adaptation set or chain
8311 may have more than 16 services, increase the limit beyond its
8312 default value of 16. If detecting infinite iteration loops sooner
8313 is critical, make the iteration limit match the actual number
8314 of services in your longest adaptation set or chain.
8316 Infinite adaptation loops are most likely with routing services.
8318 See also: icap_service routing=1
8321 NAME: adaptation_masterx_shared_names
8323 IFDEF: USE_ADAPTATION
8324 LOC: Adaptation::Config::masterx_shared_name
8327 For each master transaction (i.e., the HTTP request and response
8328 sequence, including all related ICAP and eCAP exchanges), Squid
8329 maintains a table of metadata. The table entries are (name, value)
8330 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8331 with the master transaction.
8333 This option specifies the table entry names that Squid must accept
8334 from and forward to the adaptation transactions.
8336 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8337 shared table by returning an ICAP header field with a name
8338 specified in adaptation_masterx_shared_names.
8340 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8341 shared table by implementing the libecap::visitEachOption() API
8342 to provide an option with a name specified in
8343 adaptation_masterx_shared_names.
8345 Squid will store and forward the set entry to subsequent adaptation
8346 transactions within the same master transaction scope.
8348 Only one shared entry name is supported at this time.
8351 # share authentication information among ICAP services
8352 adaptation_masterx_shared_names X-Subscriber-ID
8355 NAME: adaptation_meta
8357 IFDEF: USE_ADAPTATION
8358 LOC: Adaptation::Config::metaHeaders
8361 This option allows Squid administrator to add custom ICAP request
8362 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8363 Use it to pass custom authentication tokens and other
8364 transaction-state related meta information to an ICAP/eCAP service.
8366 The addition of a meta header is ACL-driven:
8367 adaptation_meta name value [!]aclname ...
8369 Processing for a given header name stops after the first ACL list match.
8370 Thus, it is impossible to add two headers with the same name. If no ACL
8371 lists match for a given header name, no such header is added. For
8374 # do not debug transactions except for those that need debugging
8375 adaptation_meta X-Debug 1 needs_debugging
8377 # log all transactions except for those that must remain secret
8378 adaptation_meta X-Log 1 !keep_secret
8380 # mark transactions from users in the "G 1" group
8381 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8383 The "value" parameter may be a regular squid.conf token or a "double
8384 quoted string". Within the quoted string, use backslash (\) to escape
8385 any character, which is currently only useful for escaping backslashes
8386 and double quotes. For example,
8387 "this string has one backslash (\\) and two \"quotes\""
8389 Used adaptation_meta header values may be logged via %note
8390 logformat code. If multiple adaptation_meta headers with the same name
8391 are used during master transaction lifetime, the header values are
8392 logged in the order they were used and duplicate values are ignored
8393 (only the first repeated value will be logged).
8399 LOC: Adaptation::Icap::TheConfig.repeat
8400 DEFAULT_IF_NONE: deny all
8402 This ACL determines which retriable ICAP transactions are
8403 retried. Transactions that received a complete ICAP response
8404 and did not have to consume or produce HTTP bodies to receive
8405 that response are usually retriable.
8407 icap_retry allow|deny [!]aclname ...
8409 Squid automatically retries some ICAP I/O timeouts and errors
8410 due to persistent connection race conditions.
8412 See also: icap_retry_limit
8415 NAME: icap_retry_limit
8418 LOC: Adaptation::Icap::TheConfig.repeat_limit
8420 DEFAULT_DOC: No retries are allowed.
8422 Limits the number of retries allowed.
8424 Communication errors due to persistent connection race
8425 conditions are unavoidable, automatically retried, and do not
8426 count against this limit.
8428 See also: icap_retry
8434 -----------------------------------------------------------------------------
8437 NAME: check_hostnames
8440 LOC: Config.onoff.check_hostnames
8442 For security and stability reasons Squid can check
8443 hostnames for Internet standard RFC compliance. If you want
8444 Squid to perform these checks turn this directive on.
8447 NAME: allow_underscore
8450 LOC: Config.onoff.allow_underscore
8452 Underscore characters is not strictly allowed in Internet hostnames
8453 but nevertheless used by many sites. Set this to off if you want
8454 Squid to be strict about the standard.
8455 This check is performed only when check_hostnames is set to on.
8458 NAME: dns_retransmit_interval
8461 LOC: Config.Timeout.idns_retransmit
8463 Initial retransmit interval for DNS queries. The interval is
8464 doubled each time all configured DNS servers have been tried.
8470 LOC: Config.Timeout.idns_query
8472 DNS Query timeout. If no response is received to a DNS query
8473 within this time all DNS servers for the queried domain
8474 are assumed to be unavailable.
8477 NAME: dns_packet_max
8479 DEFAULT_DOC: EDNS disabled
8481 LOC: Config.dns.packet_max
8483 Maximum number of bytes packet size to advertise via EDNS.
8484 Set to "none" to disable EDNS large packet support.
8486 For legacy reasons DNS UDP replies will default to 512 bytes which
8487 is too small for many responses. EDNS provides a means for Squid to
8488 negotiate receiving larger responses back immediately without having
8489 to failover with repeat requests. Responses larger than this limit
8490 will retain the old behaviour of failover to TCP DNS.
8492 Squid has no real fixed limit internally, but allowing packet sizes
8493 over 1500 bytes requires network jumbogram support and is usually not
8496 WARNING: The RFC also indicates that some older resolvers will reply
8497 with failure of the whole request if the extension is added. Some
8498 resolvers have already been identified which will reply with mangled
8499 EDNS response on occasion. Usually in response to many-KB jumbogram
8500 sizes being advertised by Squid.
8501 Squid will currently treat these both as an unable-to-resolve domain
8502 even if it would be resolvable without EDNS.
8509 DEFAULT_DOC: Search for single-label domain names is disabled.
8510 LOC: Config.onoff.res_defnames
8512 Normally the RES_DEFNAMES resolver option is disabled
8513 (see res_init(3)). This prevents caches in a hierarchy
8514 from interpreting single-component hostnames locally. To allow
8515 Squid to handle single-component names, enable this option.
8518 NAME: dns_multicast_local
8522 DEFAULT_DOC: Search for .local and .arpa names is disabled.
8523 LOC: Config.onoff.dns_mdns
8525 When set to on, Squid sends multicast DNS lookups on the local
8526 network for domains ending in .local and .arpa.
8527 This enables local servers and devices to be contacted in an
8528 ad-hoc or zero-configuration network environment.
8531 NAME: dns_nameservers
8534 DEFAULT_DOC: Use operating system definitions
8535 LOC: Config.dns_nameservers
8537 Use this if you want to specify a list of DNS name servers
8538 (IP addresses) to use instead of those given in your
8539 /etc/resolv.conf file.
8541 On Windows platforms, if no value is specified here or in
8542 the /etc/resolv.conf file, the list of DNS name servers are
8543 taken from the Windows registry, both static and dynamic DHCP
8544 configurations are supported.
8546 Example: dns_nameservers 10.0.0.1 192.172.0.4
8551 DEFAULT: @DEFAULT_HOSTS@
8552 LOC: Config.etcHostsPath
8554 Location of the host-local IP name-address associations
8555 database. Most Operating Systems have such a file on different
8557 - Un*X & Linux: /etc/hosts
8558 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
8559 (%SystemRoot% value install default is c:\winnt)
8560 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
8561 (%SystemRoot% value install default is c:\windows)
8562 - Windows 9x/Me: %windir%\hosts
8563 (%windir% value is usually c:\windows)
8564 - Cygwin: /etc/hosts
8566 The file contains newline-separated definitions, in the
8567 form ip_address_in_dotted_form name [name ...] names are
8568 whitespace-separated. Lines beginning with an hash (#)
8569 character are comments.
8571 The file is checked at startup and upon configuration.
8572 If set to 'none', it won't be checked.
8573 If append_domain is used, that domain will be added to
8574 domain-local (i.e. not containing any dot character) host
8580 LOC: Config.appendDomain
8582 DEFAULT_DOC: Use operating system definitions
8584 Appends local domain name to hostnames without any dots in
8585 them. append_domain must begin with a period.
8587 Be warned there are now Internet names with no dots in
8588 them using only top-domain names, so setting this may
8589 cause some Internet sites to become unavailable.
8592 append_domain .yourdomain.com
8595 NAME: ignore_unknown_nameservers
8597 LOC: Config.onoff.ignore_unknown_nameservers
8600 By default Squid checks that DNS responses are received
8601 from the same IP addresses they are sent to. If they
8602 don't match, Squid ignores the response and writes a warning
8603 message to cache.log. You can allow responses from unknown
8604 nameservers by setting this option to 'off'.
8610 LOC: Config.dns.v4_first
8612 With the IPv6 Internet being as fast or faster than IPv4 Internet
8613 for most networks Squid prefers to contact websites over IPv6.
8615 This option reverses the order of preference to make Squid contact
8616 dual-stack websites over IPv4 first. Squid will still perform both
8617 IPv6 and IPv4 DNS lookups before connecting.
8620 This option will restrict the situations under which IPv6
8621 connectivity is used (and tested). Hiding network problems
8622 which would otherwise be detected and warned about.
8626 COMMENT: (number of entries)
8629 LOC: Config.ipcache.size
8631 Maximum number of DNS IP cache entries.
8638 LOC: Config.ipcache.low
8645 LOC: Config.ipcache.high
8647 The size, low-, and high-water marks for the IP cache.
8650 NAME: fqdncache_size
8651 COMMENT: (number of entries)
8654 LOC: Config.fqdncache.size
8656 Maximum number of FQDN cache entries.
8661 -----------------------------------------------------------------------------
8664 NAME: configuration_includes_quoted_values
8666 TYPE: configuration_includes_quoted_values
8668 LOC: ConfigParser::RecognizeQuotedValues
8670 If set, Squid will recognize each "quoted string" after a configuration
8671 directive as a single parameter. The quotes are stripped before the
8672 parameter value is interpreted or used.
8673 See "Values with spaces, quotes, and other special characters"
8674 section for more details.
8681 LOC: Config.onoff.mem_pools
8683 If set, Squid will keep pools of allocated (but unused) memory
8684 available for future use. If memory is a premium on your
8685 system and you believe your malloc library outperforms Squid
8686 routines, disable this.
8689 NAME: memory_pools_limit
8693 LOC: Config.MemPools.limit
8695 Used only with memory_pools on:
8696 memory_pools_limit 50 MB
8698 If set to a non-zero value, Squid will keep at most the specified
8699 limit of allocated (but unused) memory in memory pools. All free()
8700 requests that exceed this limit will be handled by your malloc
8701 library. Squid does not pre-allocate any memory, just safe-keeps
8702 objects that otherwise would be free()d. Thus, it is safe to set
8703 memory_pools_limit to a reasonably high value even if your
8704 configuration will use less memory.
8706 If set to none, Squid will keep all memory it can. That is, there
8707 will be no limit on the total amount of memory used for safe-keeping.
8709 To disable memory allocation optimization, do not set
8710 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
8712 An overhead for maintaining memory pools is not taken into account
8713 when the limit is checked. This overhead is close to four bytes per
8714 object kept. However, pools may actually _save_ memory because of
8715 reduced memory thrashing in your malloc library.
8719 COMMENT: on|off|transparent|truncate|delete
8722 LOC: opt_forwarded_for
8724 If set to "on", Squid will append your client's IP address
8725 in the HTTP requests it forwards. By default it looks like:
8727 X-Forwarded-For: 192.1.2.3
8729 If set to "off", it will appear as
8731 X-Forwarded-For: unknown
8733 If set to "transparent", Squid will not alter the
8734 X-Forwarded-For header in any way.
8736 If set to "delete", Squid will delete the entire
8737 X-Forwarded-For header.
8739 If set to "truncate", Squid will remove all existing
8740 X-Forwarded-For entries, and place the client IP as the sole entry.
8743 NAME: cachemgr_passwd
8744 TYPE: cachemgrpasswd
8746 DEFAULT_DOC: No password. Actions which require password are denied.
8747 LOC: Config.passwd_list
8749 Specify passwords for cachemgr operations.
8751 Usage: cachemgr_passwd password action action ...
8753 Some valid actions are (see cache manager menu for a full list):
8793 * Indicates actions which will not be performed without a
8794 valid password, others can be performed if not listed here.
8796 To disable an action, set the password to "disable".
8797 To allow performing an action without a password, set the
8800 Use the keyword "all" to set the same password for all actions.
8803 cachemgr_passwd secret shutdown
8804 cachemgr_passwd lesssssssecret info stats/objects
8805 cachemgr_passwd disable all
8812 LOC: Config.onoff.client_db
8814 If you want to disable collecting per-client statistics,
8815 turn off client_db here.
8818 NAME: refresh_all_ims
8822 LOC: Config.onoff.refresh_all_ims
8824 When you enable this option, squid will always check
8825 the origin server for an update when a client sends an
8826 If-Modified-Since request. Many browsers use IMS
8827 requests when the user requests a reload, and this
8828 ensures those clients receive the latest version.
8830 By default (off), squid may return a Not Modified response
8831 based on the age of the cached version.
8834 NAME: reload_into_ims
8835 IFDEF: USE_HTTP_VIOLATIONS
8839 LOC: Config.onoff.reload_into_ims
8841 When you enable this option, client no-cache or ``reload''
8842 requests will be changed to If-Modified-Since requests.
8843 Doing this VIOLATES the HTTP standard. Enabling this
8844 feature could make you liable for problems which it
8847 see also refresh_pattern for a more selective approach.
8850 NAME: connect_retries
8852 LOC: Config.connect_retries
8854 DEFAULT_DOC: Do not retry failed connections.
8856 This sets the maximum number of connection attempts made for each
8857 TCP connection. The connect_retries attempts must all still
8858 complete within the connection timeout period.
8860 The default is not to re-try if the first connection attempt fails.
8861 The (not recommended) maximum is 10 tries.
8863 A warning message will be generated if it is set to a too-high
8864 value and the configured value will be over-ridden.
8866 Note: These re-tries are in addition to forward_max_tries
8867 which limit how many different addresses may be tried to find
8871 NAME: retry_on_error
8873 LOC: Config.retry.onerror
8876 If set to ON Squid will automatically retry requests when
8877 receiving an error response with status 403 (Forbidden),
8878 500 (Internal Error), 501 or 503 (Service not available).
8879 Status 502 and 504 (Gateway errors) are always retried.
8881 This is mainly useful if you are in a complex cache hierarchy to
8882 work around access control errors.
8884 NOTE: This retry will attempt to find another working destination.
8885 Which is different from the server which just failed.
8888 NAME: as_whois_server
8890 LOC: Config.as_whois_server
8891 DEFAULT: whois.ra.net
8893 WHOIS server to query for AS numbers. NOTE: AS numbers are
8894 queried only when Squid starts up, not for every request.
8899 LOC: Config.onoff.offline
8902 Enable this option and Squid will never try to validate cached
8906 NAME: uri_whitespace
8907 TYPE: uri_whitespace
8908 LOC: Config.uri_whitespace
8911 What to do with requests that have whitespace characters in the
8914 strip: The whitespace characters are stripped out of the URL.
8915 This is the behavior recommended by RFC2396 and RFC3986
8916 for tolerant handling of generic URI.
8917 NOTE: This is one difference between generic URI and HTTP URLs.
8919 deny: The request is denied. The user receives an "Invalid
8921 This is the behaviour recommended by RFC2616 for safe
8922 handling of HTTP request URL.
8924 allow: The request is allowed and the URI is not changed. The
8925 whitespace characters remain in the URI. Note the
8926 whitespace is passed to redirector processes if they
8928 Note this may be considered a violation of RFC2616
8929 request parsing where whitespace is prohibited in the
8932 encode: The request is allowed and the whitespace characters are
8933 encoded according to RFC1738.
8935 chop: The request is allowed and the URI is chopped at the
8939 NOTE the current Squid implementation of encode and chop violates
8940 RFC2616 by not using a 301 redirect after altering the URL.
8945 LOC: Config.chroot_dir
8948 Specifies a directory where Squid should do a chroot() while
8949 initializing. This also causes Squid to fully drop root
8950 privileges after initializing. This means, for example, if you
8951 use a HTTP port less than 1024 and try to reconfigure, you may
8952 get an error saying that Squid can not open the port.
8955 NAME: balance_on_multiple_ip
8957 LOC: Config.onoff.balance_on_multiple_ip
8960 Modern IP resolvers in squid sort lookup results by preferred access.
8961 By default squid will use these IP in order and only rotates to
8962 the next listed when the most preffered fails.
8964 Some load balancing servers based on round robin DNS have been
8965 found not to preserve user session state across requests
8966 to different IP addresses.
8968 Enabling this directive Squid rotates IP's per request.
8971 NAME: pipeline_prefetch
8972 TYPE: pipelinePrefetch
8973 LOC: Config.pipeline_max_prefetch
8975 DEFAULT_DOC: Do not pre-parse pipelined requests.
8977 HTTP clients may send a pipeline of 1+N requests to Squid using a
8978 single connection, without waiting for Squid to respond to the first
8979 of those requests. This option limits the number of concurrent
8980 requests Squid will try to handle in parallel. If set to N, Squid
8981 will try to receive and process up to 1+N requests on the same
8982 connection concurrently.
8984 Defaults to 0 (off) for bandwidth management and access logging
8987 NOTE: pipelining requires persistent connections to clients.
8989 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
8992 NAME: high_response_time_warning
8995 LOC: Config.warnings.high_rptm
8997 DEFAULT_DOC: disabled.
8999 If the one-minute median response time exceeds this value,
9000 Squid prints a WARNING with debug level 0 to get the
9001 administrators attention. The value is in milliseconds.
9004 NAME: high_page_fault_warning
9006 LOC: Config.warnings.high_pf
9008 DEFAULT_DOC: disabled.
9010 If the one-minute average page fault rate exceeds this
9011 value, Squid prints a WARNING with debug level 0 to get
9012 the administrators attention. The value is in page faults
9016 NAME: high_memory_warning
9018 LOC: Config.warnings.high_memory
9019 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
9021 DEFAULT_DOC: disabled.
9023 If the memory usage (as determined by gnumalloc, if available and used)
9024 exceeds this amount, Squid prints a WARNING with debug level 0 to get
9025 the administrators attention.
9027 # TODO: link high_memory_warning to mempools?
9029 NAME: sleep_after_fork
9030 COMMENT: (microseconds)
9032 LOC: Config.sleep_after_fork
9035 When this is set to a non-zero value, the main Squid process
9036 sleeps the specified number of microseconds after a fork()
9037 system call. This sleep may help the situation where your
9038 system reports fork() failures due to lack of (virtual)
9039 memory. Note, however, if you have a lot of child
9040 processes, these sleep delays will add up and your
9041 Squid will not service requests for some amount of time
9042 until all the child processes have been started.
9043 On Windows value less then 1000 (1 milliseconds) are
9047 NAME: windows_ipaddrchangemonitor
9048 IFDEF: _SQUID_WINDOWS_
9052 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
9054 On Windows Squid by default will monitor IP address changes and will
9055 reconfigure itself after any detected event. This is very useful for
9056 proxies connected to internet with dial-up interfaces.
9057 In some cases (a Proxy server acting as VPN gateway is one) it could be
9058 desiderable to disable this behaviour setting this to 'off'.
9059 Note: after changing this, Squid service must be restarted.
9064 IFDEF: USE_SQUID_EUI
9066 LOC: Eui::TheConfig.euiLookup
9068 Whether to lookup the EUI or MAC address of a connected client.
9071 NAME: max_filedescriptors max_filedesc
9074 DEFAULT_DOC: Use operating system limits set by ulimit.
9075 LOC: Config.max_filedescriptors
9077 Reduce the maximum number of filedescriptors supported below
9078 the usual operating system defaults.
9080 Remove from squid.conf to inherit the current ulimit setting.
9082 Note: Changing this requires a restart of Squid. Also
9083 not all I/O types supports large values (eg on Windows).
9090 DEFAULT_DOC: SMP support disabled.
9092 Number of main Squid processes or "workers" to fork and maintain.
9093 0: "no daemon" mode, like running "squid -N ..."
9094 1: "no SMP" mode, start one main Squid process daemon (default)
9095 N: start N main Squid process daemons (i.e., SMP mode)
9097 In SMP mode, each worker does nearly all what a single Squid daemon
9098 does (e.g., listen on http_port and forward HTTP requests).
9101 NAME: cpu_affinity_map
9102 TYPE: CpuAffinityMap
9103 LOC: Config.cpuAffinityMap
9105 DEFAULT_DOC: Let operating system decide.
9107 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
9109 Sets 1:1 mapping between Squid processes and CPU cores. For example,
9111 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
9113 affects processes 1 through 4 only and places them on the first
9114 four even cores, starting with core #1.
9116 CPU cores are numbered starting from 1. Requires support for
9117 sched_getaffinity(2) and sched_setaffinity(2) system calls.
9119 Multiple cpu_affinity_map options are merged.
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