2 # SQUID Web Proxy Cache http://www.squid-cache.org/
3 # ----------------------------------------------------------
5 # Squid is the result of efforts by numerous individuals from
6 # the Internet community; see the CONTRIBUTORS file for full
7 # details. Many organizations have provided support for Squid's
8 # development; see the SPONSORS file for full details. Squid is
9 # Copyrighted (C) 2000 by the Regents of the University of
10 # California; see the COPYRIGHT file for full details. Squid
11 # incorporates software developed and/or copyrighted by other
12 # sources; see the CREDITS file for full details.
14 # This program is free software; you can redistribute it and/or modify
15 # it under the terms of the GNU General Public License as published by
16 # the Free Software Foundation; either version 2 of the License, or
17 # (at your option) any later version.
19 # This program is distributed in the hope that it will be useful,
20 # but WITHOUT ANY WARRANTY; without even the implied warranty of
21 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 # GNU General Public License for more details.
24 # You should have received a copy of the GNU General Public License
25 # along with this program; if not, write to the Free Software
26 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
31 ----------------------------
33 This is the documentation for the Squid configuration file.
34 This documentation can also be found online at:
35 http://www.squid-cache.org/Doc/config/
37 You may wish to look at the Squid home page and wiki for the
38 FAQ and other documentation:
39 http://www.squid-cache.org/
40 http://wiki.squid-cache.org/SquidFaq
41 http://wiki.squid-cache.org/ConfigExamples
43 This documentation shows what the defaults for various directives
44 happen to be. If you don't need to change the default, you should
45 leave the line out of your squid.conf in most cases.
47 In some cases "none" refers to no default setting at all,
48 while in other cases it refers to the value of the option
49 - the comments for that keyword indicate if this is the case.
54 Configuration options can be included using the "include" directive.
55 Include takes a list of files to include. Quoting and wildcards are
60 include /path/to/included/file/squid.acl.config
62 Includes can be nested up to a hard-coded depth of 16 levels.
63 This arbitrary restriction is to prevent recursive include references
64 from causing Squid entering an infinite loop whilst trying to load
68 Conditional configuration
70 If-statements can be used to make configuration directives
74 ... regular configuration directives ...
76 ... regular configuration directives ...]
79 The else part is optional. The keywords "if", "else", and "endif"
80 must be typed on their own lines, as if they were regular
81 configuration directives.
83 NOTE: An else-if condition is not supported.
85 These individual conditions types are supported:
88 Always evaluates to true.
90 Always evaluates to false.
92 Equality comparison of two integer numbers.
97 The following SMP-related preprocessor macros can be used.
99 ${process_name} expands to the current Squid process "name"
100 (e.g., squid1, squid2, or cache1).
102 ${process_number} expands to the current Squid process
103 identifier, which is an integer number (e.g., 1, 2, 3) unique
104 across all Squid processes.
107 # options still not yet ported from 2.7 to 3.x
108 NAME: broken_vary_encoding
111 This option is not yet supported by Squid-3.
117 This option is not yet supported by Squid-3.
120 NAME: collapsed_forwarding
123 This option is not yet supported by Squid-3. see http://bugs.squid-cache.org/show_bug.cgi?id=3495
129 This option is not yet supported by Squid-3.
132 NAME: external_refresh_check
135 This option is not yet supported by Squid-3.
138 NAME: ignore_ims_on_miss
141 This option is not yet supported by Squid-3.
144 NAME: location_rewrite_program location_rewrite_access location_rewrite_children location_rewrite_concurrency
147 This option is not yet supported by Squid-3.
150 NAME: refresh_stale_hit
153 This option is not yet supported by Squid-3.
156 # no Options Removed in 3.3
158 # Options Removed in 3.2
159 NAME: ignore_expect_100
162 Remove this line. The HTTP/1.1 feature is now fully supported by default.
165 NAME: dns_v4_fallback
168 Remove this line. Squid performs a 'Happy Eyeballs' algorithm, the 'fallback' algorithm is no longer relevant.
174 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
177 NAME: maximum_single_addr_tries
180 Replaced by connect_retries. The behaviour has changed, please read the documentation before altering.
186 Remove this line. The feature is supported by default in storage types where update is implemented.
189 NAME: url_rewrite_concurrency
192 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
195 # Options Removed in 3.1
199 Remove this line. DNS is no longer tested on startup.
202 NAME: extension_methods
205 Remove this line. All valid methods for HTTP are accepted by default.
208 # 2.7 Options Removed/Replaced in 3.2
213 # 2.7 Options Removed/Replaced in 3.1
221 Remove this line. HTTP/1.1 is supported by default.
224 NAME: upgrade_http0.9
227 Remove this line. ICY/1.0 streaming protocol is supported by default.
230 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
233 Alter these entries. Use the qos_flows directive instead.
236 # Options Removed in 3.0
240 Since squid-3.0 replace with request_header_access or reply_header_access
241 depending on whether you wish to match client requests or server replies.
244 NAME: httpd_accel_no_pmtu_disc
247 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
250 NAME: wais_relay_host
253 Replace this line with 'cache_peer' configuration.
256 NAME: wais_relay_port
259 Replace this line with 'cache_peer' configuration.
263 OPTIONS FOR AUTHENTICATION
264 -----------------------------------------------------------------------------
273 This is used to define parameters for the various authentication
274 schemes supported by Squid.
276 format: auth_param scheme parameter [setting]
278 The order in which authentication schemes are presented to the client is
279 dependent on the order the scheme first appears in config file. IE
280 has a bug (it's not RFC 2617 compliant) in that it will use the basic
281 scheme if basic is the first entry presented, even if more secure
282 schemes are presented. For now use the order in the recommended
283 settings section below. If other browsers have difficulties (don't
284 recognize the schemes offered even if you are using basic) either
285 put basic first, or disable the other schemes (by commenting out their
288 Once an authentication scheme is fully configured, it can only be
289 shutdown by shutting squid down and restarting. Changes can be made on
290 the fly and activated with a reconfigure. I.E. You can change to a
291 different helper, but not unconfigure the helper completely.
293 Please note that while this directive defines how Squid processes
294 authentication it does not automatically activate authentication.
295 To use authentication you must in addition make use of ACLs based
296 on login name in http_access (proxy_auth, proxy_auth_regex or
297 external with %LOGIN used in the format tag). The browser will be
298 challenged for authentication on the first such acl encountered
299 in http_access processing and will also be re-challenged for new
300 login credentials if the request is being denied by a proxy_auth
303 WARNING: authentication can't be used in a transparently intercepting
304 proxy as the client then thinks it is talking to an origin server and
305 not the proxy. This is a limitation of bending the TCP/IP protocol to
306 transparently intercepting port 80, not a limitation in Squid.
307 Ports flagged 'transparent', 'intercept', or 'tproxy' have
308 authentication disabled.
310 === Parameters for the basic scheme follow. ===
313 Specify the command for the external authenticator. Such a program
314 reads a line containing "username password" and replies with one of
321 the user does not exist.
324 An internal error occurred in the helper, preventing
325 a result being identified.
327 "ERR" and "BH" results may optionally be followed by message="..."
328 containing a description available as %m in the returned error page.
330 If you use an authenticator, make sure you have 1 acl of type
333 By default, the basic authentication scheme is not used unless a
334 program is specified.
336 If you want to use the traditional NCSA proxy authentication, set
337 this line to something like
339 auth_param basic program @DEFAULT_PREFIX@/libexec/ncsa_auth @DEFAULT_PREFIX@/etc/passwd
342 HTTP uses iso-latin-1 as character set, while some authentication
343 backends such as LDAP expects UTF-8. If this is set to on Squid will
344 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
345 username & password to the helper.
347 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
348 The maximum number of authenticator processes to spawn. If you start too few
349 Squid will have to wait for them to process a backlog of credential
350 verifications, slowing it down. When password verifications are
351 done via a (slow) network you are likely to need lots of
352 authenticator processes.
354 The startup= and idle= options permit some skew in the exact amount
355 run. A minimum of startup=N will begin during startup and reconfigure.
356 Squid will start more in groups of up to idle=N in an attempt to meet
357 traffic needs and to keep idle=N free above those traffic needs up to
360 The concurrency= option sets the number of concurrent requests the
361 helper can process. The default of 0 is used for helpers who only
362 supports one request at a time. Setting this to a number greater than
363 0 changes the protocol used to include a channel number first on the
364 request/response line, allowing multiple requests to be sent to the
365 same helper in parallel without waiting for the response.
366 Must not be set unless it's known the helper supports this.
368 auth_param basic children 20 startup=0 idle=1
371 Specifies the realm name which is to be reported to the
372 client for the basic proxy authentication scheme (part of
373 the text the user will see when prompted their username and
374 password). There is no default.
375 auth_param basic realm Squid proxy-caching web server
377 "credentialsttl" timetolive
378 Specifies how long squid assumes an externally validated
379 username:password pair is valid for - in other words how
380 often the helper program is called for that user. Set this
381 low to force revalidation with short lived passwords. Note
382 setting this high does not impact your susceptibility
383 to replay attacks unless you are using an one-time password
384 system (such as SecureID). If you are using such a system,
385 you will be vulnerable to replay attacks unless you also
386 use the max_user_ip ACL in an http_access rule.
388 "casesensitive" on|off
389 Specifies if usernames are case sensitive. Most user databases are
390 case insensitive allowing the same username to be spelled using both
391 lower and upper case letters, but some are case sensitive. This
392 makes a big difference for user_max_ip ACL processing and similar.
393 auth_param basic casesensitive off
395 === Parameters for the digest scheme follow ===
398 Specify the command for the external authenticator. Such
399 a program reads a line containing "username":"realm" and
400 replies with one of three results:
403 the user exists. The ha1= key is mandatory and
404 contains the appropriate H(A1) value, hex encoded.
405 See rfc 2616 for the definition of H(A1).
408 the user does not exist.
411 An internal error occurred in the helper, preventing
412 a result being identified.
414 "ERR" and "BH" results may optionally be followed by message="..."
415 containing a description available as %m in the returned error page.
417 By default, the digest authentication scheme is not used unless a
418 program is specified.
420 If you want to use a digest authenticator, set this line to
423 auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass
426 HTTP uses iso-latin-1 as character set, while some authentication
427 backends such as LDAP expects UTF-8. If this is set to on Squid will
428 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
429 username & password to the helper.
431 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
432 The maximum number of authenticator processes to spawn (default 5).
433 If you start too few Squid will have to wait for them to
434 process a backlog of H(A1) calculations, slowing it down.
435 When the H(A1) calculations are done via a (slow) network
436 you are likely to need lots of authenticator processes.
438 The startup= and idle= options permit some skew in the exact amount
439 run. A minimum of startup=N will begin during startup and reconfigure.
440 Squid will start more in groups of up to idle=N in an attempt to meet
441 traffic needs and to keep idle=N free above those traffic needs up to
444 The concurrency= option sets the number of concurrent requests the
445 helper can process. The default of 0 is used for helpers who only
446 supports one request at a time. Setting this to a number greater than
447 0 changes the protocol used to include a channel number first on the
448 request/response line, allowing multiple requests to be sent to the
449 same helper in parallel without waiting for the response.
450 Must not be set unless it's known the helper supports this.
452 auth_param digest children 20 startup=0 idle=1
455 Specifies the realm name which is to be reported to the
456 client for the digest proxy authentication scheme (part of
457 the text the user will see when prompted their username and
458 password). There is no default.
459 auth_param digest realm Squid proxy-caching web server
461 "nonce_garbage_interval" timeinterval
462 Specifies the interval that nonces that have been issued
463 to client_agent's are checked for validity.
465 "nonce_max_duration" timeinterval
466 Specifies the maximum length of time a given nonce will be
469 "nonce_max_count" number
470 Specifies the maximum number of times a given nonce can be
473 "nonce_strictness" on|off
474 Determines if squid requires strict increment-by-1 behavior
475 for nonce counts, or just incrementing (off - for use when
476 user agents generate nonce counts that occasionally miss 1
477 (ie, 1,2,4,6)). Default off.
479 "check_nonce_count" on|off
480 This directive if set to off can disable the nonce count check
481 completely to work around buggy digest qop implementations in
482 certain mainstream browser versions. Default on to check the
483 nonce count to protect from authentication replay attacks.
485 "post_workaround" on|off
486 This is a workaround to certain buggy browsers who sends
487 an incorrect request digest in POST requests when reusing
488 the same nonce as acquired earlier on a GET request.
490 === NTLM scheme options follow ===
493 Specify the command for the external NTLM authenticator.
494 Such a program reads exchanged NTLMSSP packets with
495 the browser via Squid until authentication is completed.
496 If you use an NTLM authenticator, make sure you have 1 acl
497 of type proxy_auth. By default, the NTLM authenticator program
500 auth_param ntlm program @DEFAULT_PREFIX@/bin/ntlm_auth
502 "children" numberofchildren [startup=N] [idle=N]
503 The maximum number of authenticator processes to spawn (default 5).
504 If you start too few Squid will have to wait for them to
505 process a backlog of credential verifications, slowing it
506 down. When credential verifications are done via a (slow)
507 network you are likely to need lots of authenticator
510 The startup= and idle= options permit some skew in the exact amount
511 run. A minimum of startup=N will begin during startup and reconfigure.
512 Squid will start more in groups of up to idle=N in an attempt to meet
513 traffic needs and to keep idle=N free above those traffic needs up to
516 auth_param ntlm children 20 startup=0 idle=1
519 If you experience problems with PUT/POST requests when using the
520 Negotiate authentication scheme then you can try setting this to
521 off. This will cause Squid to forcibly close the connection on
522 the initial requests where the browser asks which schemes are
523 supported by the proxy.
525 auth_param ntlm keep_alive on
527 === Options for configuring the NEGOTIATE auth-scheme follow ===
530 Specify the command for the external Negotiate authenticator.
531 This protocol is used in Microsoft Active-Directory enabled setups with
532 the Microsoft Internet Explorer or Mozilla Firefox browsers.
533 Its main purpose is to exchange credentials with the Squid proxy
534 using the Kerberos mechanisms.
535 If you use a Negotiate authenticator, make sure you have at least
536 one acl of type proxy_auth active. By default, the negotiate
537 authenticator program is not used.
538 The only supported program for this role is the ntlm_auth
539 program distributed as part of Samba, version 4 or later.
541 auth_param negotiate program @DEFAULT_PREFIX@/bin/ntlm_auth --helper-protocol=gss-spnego
543 "children" numberofchildren [startup=N] [idle=N]
544 The maximum number of authenticator processes to spawn (default 5).
545 If you start too few Squid will have to wait for them to
546 process a backlog of credential verifications, slowing it
547 down. When credential verifications are done via a (slow)
548 network you are likely to need lots of authenticator
551 The startup= and idle= options permit some skew in the exact amount
552 run. A minimum of startup=N will begin during startup and reconfigure.
553 Squid will start more in groups of up to idle=N in an attempt to meet
554 traffic needs and to keep idle=N free above those traffic needs up to
557 auth_param negotiate children 20 startup=0 idle=1
560 If you experience problems with PUT/POST requests when using the
561 Negotiate authentication scheme then you can try setting this to
562 off. This will cause Squid to forcibly close the connection on
563 the initial requests where the browser asks which schemes are
564 supported by the proxy.
566 auth_param negotiate keep_alive on
571 #Recommended minimum configuration per scheme:
572 #auth_param negotiate program <uncomment and complete this line to activate>
573 #auth_param negotiate children 20 startup=0 idle=1
574 #auth_param negotiate keep_alive on
576 #auth_param ntlm program <uncomment and complete this line to activate>
577 #auth_param ntlm children 20 startup=0 idle=1
578 #auth_param ntlm keep_alive on
580 #auth_param digest program <uncomment and complete this line>
581 #auth_param digest children 20 startup=0 idle=1
582 #auth_param digest realm Squid proxy-caching web server
583 #auth_param digest nonce_garbage_interval 5 minutes
584 #auth_param digest nonce_max_duration 30 minutes
585 #auth_param digest nonce_max_count 50
587 #auth_param basic program <uncomment and complete this line>
588 #auth_param basic children 5 startup=5 idle=1
589 #auth_param basic realm Squid proxy-caching web server
590 #auth_param basic credentialsttl 2 hours
593 NAME: authenticate_cache_garbage_interval
596 LOC: Config.authenticateGCInterval
598 The time period between garbage collection across the username cache.
599 This is a trade-off between memory utilization (long intervals - say
600 2 days) and CPU (short intervals - say 1 minute). Only change if you
604 NAME: authenticate_ttl
607 LOC: Config.authenticateTTL
609 The time a user & their credentials stay in the logged in
610 user cache since their last request. When the garbage
611 interval passes, all user credentials that have passed their
612 TTL are removed from memory.
615 NAME: authenticate_ip_ttl
617 LOC: Config.authenticateIpTTL
620 If you use proxy authentication and the 'max_user_ip' ACL,
621 this directive controls how long Squid remembers the IP
622 addresses associated with each user. Use a small value
623 (e.g., 60 seconds) if your users might change addresses
624 quickly, as is the case with dialup. You might be safe
625 using a larger value (e.g., 2 hours) in a corporate LAN
626 environment with relatively static address assignments.
631 -----------------------------------------------------------------------------
634 NAME: external_acl_type
635 TYPE: externalAclHelper
636 LOC: Config.externalAclHelperList
639 This option defines external acl classes using a helper program
640 to look up the status
642 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
646 ttl=n TTL in seconds for cached results (defaults to 3600
649 TTL for cached negative lookups (default same
652 Maximum number of acl helper processes spawned to service
653 external acl lookups of this type. (default 20)
655 Minimum number of acl helper processes to spawn during
656 startup and reconfigure to service external acl lookups
657 of this type. (default 0)
659 Number of acl helper processes to keep ahead of traffic
660 loads. Squid will spawn this many at once whenever load
661 rises above the capabilities of existing processes.
662 Up to the value of children-max. (default 1)
663 concurrency=n concurrency level per process. Only used with helpers
664 capable of processing more than one query at a time.
665 cache=n limit the result cache size, default is unbounded.
666 grace=n Percentage remaining of TTL where a refresh of a
667 cached entry should be initiated without needing to
668 wait for a new reply. (default is for no grace period)
669 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
670 ipv4 / ipv6 IP protocol used to communicate with this helper.
671 The default is to auto-detect IPv6 and use it when available.
673 FORMAT specifications
675 %LOGIN Authenticated user login name
676 %EXT_USER Username from previous external acl
677 %EXT_LOG Log details from previous external acl
678 %EXT_TAG Tag from previous external acl
679 %IDENT Ident user name
681 %SRCPORT Client source port
684 %PROTO Requested protocol
686 %PATH Requested URL path
687 %METHOD Request method
688 %MYADDR Squid interface address
689 %MYPORT Squid http_port number
690 %PATH Requested URL-path (including query-string if any)
691 %USER_CERT SSL User certificate in PEM format
692 %USER_CERTCHAIN SSL User certificate chain in PEM format
693 %USER_CERT_xx SSL User certificate subject attribute xx
694 %USER_CA_xx SSL User certificate issuer attribute xx
696 %>{Header} HTTP request header "Header"
698 HTTP request header "Hdr" list member "member"
700 HTTP request header list member using ; as
701 list separator. ; can be any non-alphanumeric
704 %<{Header} HTTP reply header "Header"
706 HTTP reply header "Hdr" list member "member"
708 HTTP reply header list member using ; as
709 list separator. ; can be any non-alphanumeric
712 %% The percent sign. Useful for helpers which need
713 an unchanging input format.
716 General request syntax:
718 [channel-ID] FORMAT-values [acl-values ...]
721 FORMAT-values consists of transaction details expanded with
722 whitespace separation per the config file FORMAT specification
723 using the FORMAT macros listed above.
725 acl-values consists of any string specified in the referencing
726 config 'acl ... external' line. see the "acl external" directive.
728 Request values sent to the helper are URL escaped to protect
729 each value in requests against whitespaces.
731 If using protocol=2.5 then the request sent to the helper is not
732 URL escaped to protect against whitespace.
734 NOTE: protocol=3.0 is deprecated as no longer necessary.
736 When using the concurrency= option the protocol is changed by
737 introducing a query channel tag in front of the request/response.
738 The query channel tag is a number between 0 and concurrency-1.
739 This value must be echoed back unchanged to Squid as the first part
740 of the response relating to its request.
743 The helper receives lines expanded per the above format specification
744 and for each input line returns 1 line starting with OK/ERR/BH result
745 code and optionally followed by additional keywords with more details.
748 General result syntax:
750 [channel-ID] result keyword=value ...
752 Result consists of one of the codes:
755 the ACL test produced a match.
758 the ACL test does not produce a match.
761 An internal error occurred in the helper, preventing
762 a result being identified.
764 The meaning of 'a match' is determined by your squid.conf
765 access control configuration. See the Squid wiki for details.
769 user= The users name (login)
771 password= The users password (for login= cache_peer option)
773 message= Message describing the reason for this response.
774 Available as %o in error pages.
775 Useful on (ERR and BH results).
777 tag= Apply a tag to a request. Only sets a tag once,
778 does not alter existing tags.
780 log= String to be logged in access.log. Available as
781 %ea in logformat specifications.
783 Any keywords may be sent on any response whether OK, ERR or BH.
785 All response keyword values need to be a single token with URL
786 escaping, or enclosed in double quotes (") and escaped using \ on
787 any double quotes or \ characters within the value. The wrapping
788 double quotes are removed before the value is interpreted by Squid.
789 \r and \n are also replace by CR and LF.
791 Some example key values:
795 user="J. \"Bob\" Smith"
802 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
803 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
804 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
805 DEFAULT: ssl::certUntrusted ssl_error X509_V_ERR_INVALID_CA X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY X509_V_ERR_CERT_UNTRUSTED
806 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
809 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
810 DEFAULT: localhost src 127.0.0.1/32 ::1
811 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
812 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
814 Defining an Access List
816 Every access list definition must begin with an aclname and acltype,
817 followed by either type-specific arguments or a quoted filename that
820 acl aclname acltype argument ...
821 acl aclname acltype "file" ...
823 When using "file", the file should contain one item per line.
825 By default, regular expressions are CASE-SENSITIVE.
826 To make them case-insensitive, use the -i option. To return case-sensitive
827 use the +i option between patterns, or make a new ACL line without -i.
829 Some acl types require suspending the current request in order
830 to access some external data source.
831 Those which do are marked with the tag [slow], those which
832 don't are marked as [fast].
833 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
834 for further information
836 ***** ACL TYPES AVAILABLE *****
838 acl aclname src ip-address/mask ... # clients IP address [fast]
839 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
840 acl aclname dst ip-address/mask ... # URL host's IP address [slow]
841 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
843 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
844 # The arp ACL requires the special configure option --enable-arp-acl.
845 # Furthermore, the ARP ACL code is not portable to all operating systems.
846 # It works on Linux, Solaris, Windows, FreeBSD, and some
847 # other *BSD variants.
850 # NOTE: Squid can only determine the MAC address for clients that are on
851 # the same subnet. If the client is on a different subnet,
852 # then Squid cannot find out its MAC address.
854 acl aclname srcdomain .foo.com ...
855 # reverse lookup, from client IP [slow]
856 acl aclname dstdomain .foo.com ...
857 # Destination server from URL [fast]
858 acl aclname srcdom_regex [-i] \.foo\.com ...
859 # regex matching client name [slow]
860 acl aclname dstdom_regex [-i] \.foo\.com ...
861 # regex matching server [fast]
863 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
864 # based URL is used and no match is found. The name "none" is used
865 # if the reverse lookup fails.
867 acl aclname src_as number ...
868 acl aclname dst_as number ...
870 # Except for access control, AS numbers can be used for
871 # routing of requests to specific caches. Here's an
872 # example for routing all requests for AS#1241 and only
873 # those to mycache.mydomain.net:
874 # acl asexample dst_as 1241
875 # cache_peer_access mycache.mydomain.net allow asexample
876 # cache_peer_access mycache_mydomain.net deny all
878 acl aclname peername myPeer ...
880 # match against a named cache_peer entry
881 # set unique name= on cache_peer lines for reliable use.
883 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
893 # h1:m1 must be less than h2:m2
895 acl aclname url_regex [-i] ^http:// ...
896 # regex matching on whole URL [fast]
897 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
898 # regex matching on URL login field
899 acl aclname urlpath_regex [-i] \.gif$ ...
900 # regex matching on URL path [fast]
902 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
904 acl aclname localport 3128 ... # TCP port the client connected to [fast]
905 # NP: for interception mode this is usually '80'
907 acl aclname myportname 3128 ... # http(s)_port name [fast]
909 acl aclname proto HTTP FTP ... # request protocol [fast]
911 acl aclname method GET POST ... # HTTP request method [fast]
913 acl aclname http_status 200 301 500- 400-403 ...
914 # status code in reply [fast]
916 acl aclname browser [-i] regexp ...
917 # pattern match on User-Agent header (see also req_header below) [fast]
919 acl aclname referer_regex [-i] regexp ...
920 # pattern match on Referer header [fast]
921 # Referer is highly unreliable, so use with care
923 acl aclname ident username ...
924 acl aclname ident_regex [-i] pattern ...
925 # string match on ident output [slow]
926 # use REQUIRED to accept any non-null ident.
928 acl aclname proxy_auth [-i] username ...
929 acl aclname proxy_auth_regex [-i] pattern ...
930 # perform http authentication challenge to the client and match against
931 # supplied credentials [slow]
933 # takes a list of allowed usernames.
934 # use REQUIRED to accept any valid username.
936 # Will use proxy authentication in forward-proxy scenarios, and plain
937 # http authenticaiton in reverse-proxy scenarios
939 # NOTE: when a Proxy-Authentication header is sent but it is not
940 # needed during ACL checking the username is NOT logged
943 # NOTE: proxy_auth requires a EXTERNAL authentication program
944 # to check username/password combinations (see
945 # auth_param directive).
947 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
948 # as the browser needs to be configured for using a proxy in order
949 # to respond to proxy authentication.
951 acl aclname snmp_community string ...
952 # A community string to limit access to your SNMP Agent [fast]
955 # acl snmppublic snmp_community public
957 acl aclname maxconn number
958 # This will be matched when the client's IP address has
959 # more than <number> TCP connections established. [fast]
960 # NOTE: This only measures direct TCP links so X-Forwarded-For
961 # indirect clients are not counted.
963 acl aclname max_user_ip [-s] number
964 # This will be matched when the user attempts to log in from more
965 # than <number> different ip addresses. The authenticate_ip_ttl
966 # parameter controls the timeout on the ip entries. [fast]
967 # If -s is specified the limit is strict, denying browsing
968 # from any further IP addresses until the ttl has expired. Without
969 # -s Squid will just annoy the user by "randomly" denying requests.
970 # (the counter is reset each time the limit is reached and a
972 # NOTE: in acceleration mode or where there is mesh of child proxies,
973 # clients may appear to come from multiple addresses if they are
974 # going through proxy farms, so a limit of 1 may cause user problems.
976 acl aclname random probability
977 # Pseudo-randomly match requests. Based on the probability given.
978 # Probability may be written as a decimal (0.333), fraction (1/3)
979 # or ratio of matches:non-matches (3:5).
981 acl aclname req_mime_type [-i] mime-type ...
982 # regex match against the mime type of the request generated
983 # by the client. Can be used to detect file upload or some
984 # types HTTP tunneling requests [fast]
985 # NOTE: This does NOT match the reply. You cannot use this
986 # to match the returned file type.
988 acl aclname req_header header-name [-i] any\.regex\.here
989 # regex match against any of the known request headers. May be
990 # thought of as a superset of "browser", "referer" and "mime-type"
993 acl aclname rep_mime_type [-i] mime-type ...
994 # regex match against the mime type of the reply received by
995 # squid. Can be used to detect file download or some
996 # types HTTP tunneling requests. [fast]
997 # NOTE: This has no effect in http_access rules. It only has
998 # effect in rules that affect the reply data stream such as
1001 acl aclname rep_header header-name [-i] any\.regex\.here
1002 # regex match against any of the known reply headers. May be
1003 # thought of as a superset of "browser", "referer" and "mime-type"
1006 acl aclname external class_name [arguments...]
1007 # external ACL lookup via a helper class defined by the
1008 # external_acl_type directive [slow]
1010 acl aclname user_cert attribute values...
1011 # match against attributes in a user SSL certificate
1012 # attribute is one of DN/C/O/CN/L/ST [fast]
1014 acl aclname ca_cert attribute values...
1015 # match against attributes a users issuing CA SSL certificate
1016 # attribute is one of DN/C/O/CN/L/ST [fast]
1018 acl aclname ext_user username ...
1019 acl aclname ext_user_regex [-i] pattern ...
1020 # string match on username returned by external acl helper [slow]
1021 # use REQUIRED to accept any non-null user name.
1023 acl aclname tag tagvalue ...
1024 # string match on tag returned by external acl helper [slow]
1026 acl aclname hier_code codename ...
1027 # string match against squid hierarchy code(s); [fast]
1028 # e.g., DIRECT, PARENT_HIT, NONE, etc.
1030 # NOTE: This has no effect in http_access rules. It only has
1031 # effect in rules that affect the reply data stream such as
1032 # http_reply_access.
1035 acl aclname ssl_error errorname
1036 # match against SSL certificate validation error [fast]
1038 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1041 # The following can be used as shortcuts for certificate properties:
1042 # [ssl::]certHasExpired: the "not after" field is in the past
1043 # [ssl::]certNotYetValid: the "not before" field is in the future
1044 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1045 # [ssl::]certSelfSigned: The certificate is self signed.
1046 # [ssl::]certDomainMismatch: The certificate CN domain does not
1047 # match the name the name of the host we are connecting to.
1049 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1050 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1051 # predefined ACLs, just like the 'all' ACL.
1053 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1054 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1056 acl aclname server_cert_fingerprint [-sha1] fingerprint
1057 # match against server SSL certificate fingerprint [fast]
1059 # The fingerprint is the digest of the DER encoded version
1060 # of the whole certificate. The user should use the form: XX:XX:...
1061 # Optional argument specifies the digest algorithm to use.
1062 # The SHA1 digest algorithm is the default and is currently
1063 # the only algorithm supported (-sha1).
1067 acl macaddress arp 09:00:2b:23:45:67
1068 acl myexample dst_as 1241
1069 acl password proxy_auth REQUIRED
1070 acl fileupload req_mime_type -i ^multipart/form-data$
1071 acl javascript rep_mime_type -i ^application/x-javascript$
1075 # Recommended minimum configuration:
1078 # Example rule allowing access from your local networks.
1079 # Adapt to list your (internal) IP networks from where browsing
1081 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
1082 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
1083 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
1084 acl localnet src fc00::/7 # RFC 4193 local private network range
1085 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1087 acl SSL_ports port 443
1088 acl Safe_ports port 80 # http
1089 acl Safe_ports port 21 # ftp
1090 acl Safe_ports port 443 # https
1091 acl Safe_ports port 70 # gopher
1092 acl Safe_ports port 210 # wais
1093 acl Safe_ports port 1025-65535 # unregistered ports
1094 acl Safe_ports port 280 # http-mgmt
1095 acl Safe_ports port 488 # gss-http
1096 acl Safe_ports port 591 # filemaker
1097 acl Safe_ports port 777 # multiling http
1098 acl CONNECT method CONNECT
1102 NAME: follow_x_forwarded_for
1104 IFDEF: FOLLOW_X_FORWARDED_FOR
1105 LOC: Config.accessList.followXFF
1106 DEFAULT_IF_NONE: deny all
1108 Allowing or Denying the X-Forwarded-For header to be followed to
1109 find the original source of a request.
1111 Requests may pass through a chain of several other proxies
1112 before reaching us. The X-Forwarded-For header will contain a
1113 comma-separated list of the IP addresses in the chain, with the
1114 rightmost address being the most recent.
1116 If a request reaches us from a source that is allowed by this
1117 configuration item, then we consult the X-Forwarded-For header
1118 to see where that host received the request from. If the
1119 X-Forwarded-For header contains multiple addresses, we continue
1120 backtracking until we reach an address for which we are not allowed
1121 to follow the X-Forwarded-For header, or until we reach the first
1122 address in the list. For the purpose of ACL used in the
1123 follow_x_forwarded_for directive the src ACL type always matches
1124 the address we are testing and srcdomain matches its rDNS.
1126 The end result of this process is an IP address that we will
1127 refer to as the indirect client address. This address may
1128 be treated as the client address for access control, ICAP, delay
1129 pools and logging, depending on the acl_uses_indirect_client,
1130 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1131 log_uses_indirect_client and tproxy_uses_indirect_client options.
1133 This clause only supports fast acl types.
1134 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1136 SECURITY CONSIDERATIONS:
1138 Any host for which we follow the X-Forwarded-For header
1139 can place incorrect information in the header, and Squid
1140 will use the incorrect information as if it were the
1141 source address of the request. This may enable remote
1142 hosts to bypass any access control restrictions that are
1143 based on the client's source addresses.
1147 acl localhost src 127.0.0.1
1148 acl my_other_proxy srcdomain .proxy.example.com
1149 follow_x_forwarded_for allow localhost
1150 follow_x_forwarded_for allow my_other_proxy
1153 NAME: acl_uses_indirect_client
1156 IFDEF: FOLLOW_X_FORWARDED_FOR
1158 LOC: Config.onoff.acl_uses_indirect_client
1160 Controls whether the indirect client address
1161 (see follow_x_forwarded_for) is used instead of the
1162 direct client address in acl matching.
1164 NOTE: maxconn ACL considers direct TCP links and indirect
1165 clients will always have zero. So no match.
1168 NAME: delay_pool_uses_indirect_client
1171 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1173 LOC: Config.onoff.delay_pool_uses_indirect_client
1175 Controls whether the indirect client address
1176 (see follow_x_forwarded_for) is used instead of the
1177 direct client address in delay pools.
1180 NAME: log_uses_indirect_client
1183 IFDEF: FOLLOW_X_FORWARDED_FOR
1185 LOC: Config.onoff.log_uses_indirect_client
1187 Controls whether the indirect client address
1188 (see follow_x_forwarded_for) is used instead of the
1189 direct client address in the access log.
1192 NAME: tproxy_uses_indirect_client
1195 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1197 LOC: Config.onoff.tproxy_uses_indirect_client
1199 Controls whether the indirect client address
1200 (see follow_x_forwarded_for) is used instead of the
1201 direct client address when spoofing the outgoing client.
1203 This has no effect on requests arriving in non-tproxy
1206 SECURITY WARNING: Usage of this option is dangerous
1207 and should not be used trivially. Correct configuration
1208 of follow_x_forewarded_for with a limited set of trusted
1209 sources is required to prevent abuse of your proxy.
1214 LOC: Config.accessList.http
1215 DEFAULT_IF_NONE: deny all
1217 Allowing or Denying access based on defined access lists
1219 Access to the HTTP port:
1220 http_access allow|deny [!]aclname ...
1222 NOTE on default values:
1224 If there are no "access" lines present, the default is to deny
1227 If none of the "access" lines cause a match, the default is the
1228 opposite of the last line in the list. If the last line was
1229 deny, the default is allow. Conversely, if the last line
1230 is allow, the default will be deny. For these reasons, it is a
1231 good idea to have an "deny all" entry at the end of your access
1232 lists to avoid potential confusion.
1234 This clause supports both fast and slow acl types.
1235 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1240 # Recommended minimum Access Permission configuration:
1242 # Only allow cachemgr access from localhost
1243 http_access allow localhost manager
1244 http_access deny manager
1246 # Deny requests to certain unsafe ports
1247 http_access deny !Safe_ports
1249 # Deny CONNECT to other than secure SSL ports
1250 http_access deny CONNECT !SSL_ports
1252 # We strongly recommend the following be uncommented to protect innocent
1253 # web applications running on the proxy server who think the only
1254 # one who can access services on "localhost" is a local user
1255 #http_access deny to_localhost
1258 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1261 # Example rule allowing access from your local networks.
1262 # Adapt localnet in the ACL section to list your (internal) IP networks
1263 # from where browsing should be allowed
1264 http_access allow localnet
1265 http_access allow localhost
1267 # And finally deny all other access to this proxy
1268 http_access deny all
1272 NAME: adapted_http_access http_access2
1274 LOC: Config.accessList.adapted_http
1277 Allowing or Denying access based on defined access lists
1279 Essentially identical to http_access, but runs after redirectors
1280 and ICAP/eCAP adaptation. Allowing access control based on their
1283 If not set then only http_access is used.
1286 NAME: http_reply_access
1288 LOC: Config.accessList.reply
1291 Allow replies to client requests. This is complementary to http_access.
1293 http_reply_access allow|deny [!] aclname ...
1295 NOTE: if there are no access lines present, the default is to allow
1298 If none of the access lines cause a match the opposite of the
1299 last line will apply. Thus it is good practice to end the rules
1300 with an "allow all" or "deny all" entry.
1302 This clause supports both fast and slow acl types.
1303 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1308 LOC: Config.accessList.icp
1309 DEFAULT_IF_NONE: deny all
1311 Allowing or Denying access to the ICP port based on defined
1314 icp_access allow|deny [!]aclname ...
1316 See http_access for details
1318 This clause only supports fast acl types.
1319 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1321 # Allow ICP queries from local networks only
1322 #icp_access allow localnet
1323 #icp_access deny all
1329 LOC: Config.accessList.htcp
1330 DEFAULT_IF_NONE: deny all
1332 Allowing or Denying access to the HTCP port based on defined
1335 htcp_access allow|deny [!]aclname ...
1337 See http_access for details
1339 NOTE: The default if no htcp_access lines are present is to
1340 deny all traffic. This default may cause problems with peers
1341 using the htcp option.
1343 This clause only supports fast acl types.
1344 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1346 # Allow HTCP queries from local networks only
1347 #htcp_access allow localnet
1348 #htcp_access deny all
1351 NAME: htcp_clr_access
1354 LOC: Config.accessList.htcp_clr
1355 DEFAULT_IF_NONE: deny all
1357 Allowing or Denying access to purge content using HTCP based
1358 on defined access lists
1360 htcp_clr_access allow|deny [!]aclname ...
1362 See http_access for details
1364 This clause only supports fast acl types.
1365 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1367 # Allow HTCP CLR requests from trusted peers
1368 acl htcp_clr_peer src 172.16.1.2
1369 htcp_clr_access allow htcp_clr_peer
1374 LOC: Config.accessList.miss
1377 Determins whether network access is permitted when satisfying a request.
1380 to force your neighbors to use you as a sibling instead of
1383 acl localclients src 172.16.0.0/16
1384 miss_access allow localclients
1385 miss_access deny !localclients
1387 This means only your local clients are allowed to fetch relayed/MISS
1388 replies from the network and all other clients can only fetch cached
1392 The default for this setting allows all clients who passed the
1393 http_access rules to relay via this proxy.
1395 This clause only supports fast acl types.
1396 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1399 NAME: ident_lookup_access
1402 DEFAULT_IF_NONE: deny all
1403 LOC: Ident::TheConfig.identLookup
1405 A list of ACL elements which, if matched, cause an ident
1406 (RFC 931) lookup to be performed for this request. For
1407 example, you might choose to always perform ident lookups
1408 for your main multi-user Unix boxes, but not for your Macs
1409 and PCs. By default, ident lookups are not performed for
1412 To enable ident lookups for specific client addresses, you
1413 can follow this example:
1415 acl ident_aware_hosts src 198.168.1.0/24
1416 ident_lookup_access allow ident_aware_hosts
1417 ident_lookup_access deny all
1419 Only src type ACL checks are fully supported. A srcdomain
1420 ACL might work at times, but it will not always provide
1423 This clause only supports fast acl types.
1424 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1427 NAME: reply_body_max_size
1428 COMMENT: size [acl acl...]
1431 LOC: Config.ReplyBodySize
1433 This option specifies the maximum size of a reply body. It can be
1434 used to prevent users from downloading very large files, such as
1435 MP3's and movies. When the reply headers are received, the
1436 reply_body_max_size lines are processed, and the first line where
1437 all (if any) listed ACLs are true is used as the maximum body size
1440 This size is checked twice. First when we get the reply headers,
1441 we check the content-length value. If the content length value exists
1442 and is larger than the allowed size, the request is denied and the
1443 user receives an error message that says "the request or reply
1444 is too large." If there is no content-length, and the reply
1445 size exceeds this limit, the client's connection is just closed
1446 and they will receive a partial reply.
1448 WARNING: downstream caches probably can not detect a partial reply
1449 if there is no content-length header, so they will cache
1450 partial responses and give them out as hits. You should NOT
1451 use this option if you have downstream caches.
1453 WARNING: A maximum size smaller than the size of squid's error messages
1454 will cause an infinite loop and crash squid. Ensure that the smallest
1455 non-zero value you use is greater that the maximum header size plus
1456 the size of your largest error page.
1458 If you set this parameter none (the default), there will be
1461 Configuration Format is:
1462 reply_body_max_size SIZE UNITS [acl ...]
1464 reply_body_max_size 10 MB
1470 -----------------------------------------------------------------------------
1473 NAME: http_port ascii_port
1476 LOC: Config.Sockaddr.http
1478 Usage: port [mode] [options]
1479 hostname:port [mode] [options]
1480 1.2.3.4:port [mode] [options]
1482 The socket addresses where Squid will listen for HTTP client
1483 requests. You may specify multiple socket addresses.
1484 There are three forms: port alone, hostname with port, and
1485 IP address with port. If you specify a hostname or IP
1486 address, Squid binds the socket to that specific
1487 address. Most likely, you do not need to bind to a specific
1488 address, so you can use the port number alone.
1490 If you are running Squid in accelerator mode, you
1491 probably want to listen on port 80 also, or instead.
1493 The -a command line option may be used to specify additional
1494 port(s) where Squid listens for proxy request. Such ports will
1495 be plain proxy ports with no options.
1497 You may specify multiple socket addresses on multiple lines.
1501 intercept Support for IP-Layer interception of
1502 outgoing requests without browser settings.
1503 NP: disables authentication and IPv6 on the port.
1505 tproxy Support Linux TPROXY for spoofing outgoing
1506 connections using the client IP address.
1507 NP: disables authentication and maybe IPv6 on the port.
1509 accel Accelerator / reverse proxy mode
1511 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1512 establish secure connection with the client and with
1513 the server, decrypt HTTPS messages as they pass through
1514 Squid, and treat them as unencrypted HTTP messages,
1515 becoming the man-in-the-middle.
1517 The ssl_bump option is required to fully enable
1518 bumping of CONNECT requests.
1520 Omitting the mode flag causes default forward proxy mode to be used.
1523 Accelerator Mode Options:
1525 defaultsite=domainname
1526 What to use for the Host: header if it is not present
1527 in a request. Determines what site (not origin server)
1528 accelerators should consider the default.
1530 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1532 protocol= Protocol to reconstruct accelerated requests with.
1533 Defaults to http for http_port and https for
1536 vport Virtual host port support. Using the http_port number
1537 instead of the port passed on Host: headers.
1539 vport=NN Virtual host port support. Using the specified port
1540 number instead of the port passed on Host: headers.
1543 Act as if this Squid is the origin server.
1544 This currently means generate new Date: and Expires:
1545 headers on HIT instead of adding Age:.
1547 ignore-cc Ignore request Cache-Control headers.
1549 WARNING: This option violates HTTP specifications if
1550 used in non-accelerator setups.
1552 allow-direct Allow direct forwarding in accelerator mode. Normally
1553 accelerated requests are denied direct forwarding as if
1554 never_direct was used.
1556 WARNING: this option opens accelerator mode to security
1557 vulnerabilities usually only affecting in interception
1558 mode. Make sure to protect forwarding with suitable
1559 http_access rules when using this.
1562 SSL Bump Mode Options:
1563 In addition to these options ssl-bump requires TLS/SSL options.
1565 generate-host-certificates[=<on|off>]
1566 Dynamically create SSL server certificates for the
1567 destination hosts of bumped CONNECT requests.When
1568 enabled, the cert and key options are used to sign
1569 generated certificates. Otherwise generated
1570 certificate will be selfsigned.
1571 If there is a CA certificate lifetime of the generated
1572 certificate equals lifetime of the CA certificate. If
1573 generated certificate is selfsigned lifetime is three
1575 This option is enabled by default when ssl-bump is used.
1576 See the ssl-bump option above for more information.
1578 dynamic_cert_mem_cache_size=SIZE
1579 Approximate total RAM size spent on cached generated
1580 certificates. If set to zero, caching is disabled. The
1581 default value is 4MB.
1585 cert= Path to SSL certificate (PEM format).
1587 key= Path to SSL private key file (PEM format)
1588 if not specified, the certificate file is
1589 assumed to be a combined certificate and
1592 version= The version of SSL/TLS supported
1593 1 automatic (default)
1600 cipher= Colon separated list of supported ciphers.
1601 NOTE: some ciphers such as EDH ciphers depend on
1602 additional settings. If those settings are
1603 omitted the ciphers may be silently ignored
1604 by the OpenSSL library.
1606 options= Various SSL implementation options. The most important
1608 NO_SSLv2 Disallow the use of SSLv2
1609 NO_SSLv3 Disallow the use of SSLv3
1610 NO_TLSv1 Disallow the use of TLSv1.0
1611 NO_TLSv1_1 Disallow the use of TLSv1.1
1612 NO_TLSv1_2 Disallow the use of TLSv1.2
1613 SINGLE_DH_USE Always create a new key when using
1614 temporary/ephemeral DH key exchanges
1615 ALL Enable various bug workarounds
1616 suggested as "harmless" by OpenSSL
1617 Be warned that this reduces SSL/TLS
1618 strength to some attacks.
1619 See OpenSSL SSL_CTX_set_options documentation for a
1620 complete list of options.
1622 clientca= File containing the list of CAs to use when
1623 requesting a client certificate.
1625 cafile= File containing additional CA certificates to
1626 use when verifying client certificates. If unset
1627 clientca will be used.
1629 capath= Directory containing additional CA certificates
1630 and CRL lists to use when verifying client certificates.
1632 crlfile= File of additional CRL lists to use when verifying
1633 the client certificate, in addition to CRLs stored in
1634 the capath. Implies VERIFY_CRL flag below.
1636 dhparams= File containing DH parameters for temporary/ephemeral
1637 DH key exchanges. See OpenSSL documentation for details
1638 on how to create this file.
1639 WARNING: EDH ciphers will be silently disabled if this
1642 sslflags= Various flags modifying the use of SSL:
1644 Don't request client certificates
1645 immediately, but wait until acl processing
1646 requires a certificate (not yet implemented).
1648 Don't use the default CA lists built in
1651 Don't allow for session reuse. Each connection
1652 will result in a new SSL session.
1654 Verify CRL lists when accepting client
1657 Verify CRL lists for all certificates in the
1658 client certificate chain.
1660 sslcontext= SSL session ID context identifier.
1664 connection-auth[=on|off]
1665 use connection-auth=off to tell Squid to prevent
1666 forwarding Microsoft connection oriented authentication
1667 (NTLM, Negotiate and Kerberos)
1669 disable-pmtu-discovery=
1670 Control Path-MTU discovery usage:
1671 off lets OS decide on what to do (default).
1672 transparent disable PMTU discovery when transparent
1674 always disable always PMTU discovery.
1676 In many setups of transparently intercepting proxies
1677 Path-MTU discovery can not work on traffic towards the
1678 clients. This is the case when the intercepting device
1679 does not fully track connections and fails to forward
1680 ICMP must fragment messages to the cache server. If you
1681 have such setup and experience that certain clients
1682 sporadically hang or never complete requests set
1683 disable-pmtu-discovery option to 'transparent'.
1685 name= Specifies a internal name for the port. Defaults to
1686 the port specification (port or addr:port)
1688 tcpkeepalive[=idle,interval,timeout]
1689 Enable TCP keepalive probes of idle connections.
1690 In seconds; idle is the initial time before TCP starts
1691 probing the connection, interval how often to probe, and
1692 timeout the time before giving up.
1694 If you run Squid on a dual-homed machine with an internal
1695 and an external interface we recommend you to specify the
1696 internal address:port in http_port. This way Squid will only be
1697 visible on the internal address.
1701 # Squid normally listens to port 3128
1702 http_port @DEFAULT_HTTP_PORT@
1710 LOC: Config.Sockaddr.https
1712 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1714 The socket address where Squid will listen for client requests made
1715 over TLS or SSL connections. Commonly referred to as HTTPS.
1717 This is most useful for situations where you are running squid in
1718 accelerator mode and you want to do the SSL work at the accelerator level.
1720 You may specify multiple socket addresses on multiple lines,
1721 each with their own SSL certificate and/or options.
1725 accel Accelerator / reverse proxy mode
1727 intercept Support for IP-Layer interception of
1728 outgoing requests without browser settings.
1729 NP: disables authentication and IPv6 on the port.
1731 tproxy Support Linux TPROXY for spoofing outgoing
1732 connections using the client IP address.
1733 NP: disables authentication and maybe IPv6 on the port.
1735 ssl-bump For each intercepted connection allowed by ssl_bump
1736 ACLs, establish a secure connection with the client and with
1737 the server, decrypt HTTPS messages as they pass through
1738 Squid, and treat them as unencrypted HTTP messages,
1739 becoming the man-in-the-middle.
1741 An "ssl_bump server-first" match is required to
1742 fully enable bumping of intercepted SSL connections.
1744 Requires tproxy or intercept.
1746 Omitting the mode flag causes default forward proxy mode to be used.
1749 See http_port for a list of generic options
1754 cert= Path to SSL certificate (PEM format).
1756 key= Path to SSL private key file (PEM format)
1757 if not specified, the certificate file is
1758 assumed to be a combined certificate and
1761 version= The version of SSL/TLS supported
1762 1 automatic (default)
1767 cipher= Colon separated list of supported ciphers.
1769 options= Various SSL engine options. The most important
1771 NO_SSLv2 Disallow the use of SSLv2
1772 NO_SSLv3 Disallow the use of SSLv3
1773 NO_TLSv1 Disallow the use of TLSv1
1774 SINGLE_DH_USE Always create a new key when using
1775 temporary/ephemeral DH key exchanges
1776 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1777 documentation for a complete list of options.
1779 clientca= File containing the list of CAs to use when
1780 requesting a client certificate.
1782 cafile= File containing additional CA certificates to
1783 use when verifying client certificates. If unset
1784 clientca will be used.
1786 capath= Directory containing additional CA certificates
1787 and CRL lists to use when verifying client certificates.
1789 crlfile= File of additional CRL lists to use when verifying
1790 the client certificate, in addition to CRLs stored in
1791 the capath. Implies VERIFY_CRL flag below.
1793 dhparams= File containing DH parameters for temporary/ephemeral
1796 sslflags= Various flags modifying the use of SSL:
1798 Don't request client certificates
1799 immediately, but wait until acl processing
1800 requires a certificate (not yet implemented).
1802 Don't use the default CA lists built in
1805 Don't allow for session reuse. Each connection
1806 will result in a new SSL session.
1808 Verify CRL lists when accepting client
1811 Verify CRL lists for all certificates in the
1812 client certificate chain.
1814 sslcontext= SSL session ID context identifier.
1816 generate-host-certificates[=<on|off>]
1817 Dynamically create SSL server certificates for the
1818 destination hosts of bumped SSL requests.When
1819 enabled, the cert and key options are used to sign
1820 generated certificates. Otherwise generated
1821 certificate will be selfsigned.
1822 If there is CA certificate life time of generated
1823 certificate equals lifetime of CA certificate. If
1824 generated certificate is selfsigned lifetime is three
1826 This option is enabled by default when SslBump is used.
1827 See the sslBump option above for more information.
1829 dynamic_cert_mem_cache_size=SIZE
1830 Approximate total RAM size spent on cached generated
1831 certificates. If set to zero, caching is disabled. The
1832 default value is 4MB.
1834 See http_port for a list of available options.
1837 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1840 LOC: Ip::Qos::TheConfig.tosToServer
1842 Allows you to select a TOS/Diffserv value for packets outgoing
1843 on the server side, based on an ACL.
1845 tcp_outgoing_tos ds-field [!]aclname ...
1847 Example where normal_service_net uses the TOS value 0x00
1848 and good_service_net uses 0x20
1850 acl normal_service_net src 10.0.0.0/24
1851 acl good_service_net src 10.0.1.0/24
1852 tcp_outgoing_tos 0x00 normal_service_net
1853 tcp_outgoing_tos 0x20 good_service_net
1855 TOS/DSCP values really only have local significance - so you should
1856 know what you're specifying. For more information, see RFC2474,
1857 RFC2475, and RFC3260.
1859 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1860 "default" to use whatever default your host has. Note that in
1861 practice often only multiples of 4 is usable as the two rightmost bits
1862 have been redefined for use by ECN (RFC 3168 section 23.1).
1864 Processing proceeds in the order specified, and stops at first fully
1868 NAME: clientside_tos
1871 LOC: Ip::Qos::TheConfig.tosToClient
1873 Allows you to select a TOS/Diffserv value for packets being transmitted
1874 on the client-side, based on an ACL.
1876 clientside_tos ds-field [!]aclname ...
1878 Example where normal_service_net uses the TOS value 0x00
1879 and good_service_net uses 0x20
1881 acl normal_service_net src 10.0.0.0/24
1882 acl good_service_net src 10.0.1.0/24
1883 clientside_tos 0x00 normal_service_net
1884 clientside_tos 0x20 good_service_net
1886 Note: This feature is incompatible with qos_flows. Any TOS values set here
1887 will be overwritten by TOS values in qos_flows.
1890 NAME: tcp_outgoing_mark
1892 IFDEF: SO_MARK&&USE_LIBCAP
1894 LOC: Ip::Qos::TheConfig.nfmarkToServer
1896 Allows you to apply a Netfilter mark value to outgoing packets
1897 on the server side, based on an ACL.
1899 tcp_outgoing_mark mark-value [!]aclname ...
1901 Example where normal_service_net uses the mark value 0x00
1902 and good_service_net uses 0x20
1904 acl normal_service_net src 10.0.0.0/24
1905 acl good_service_net src 10.0.1.0/24
1906 tcp_outgoing_mark 0x00 normal_service_net
1907 tcp_outgoing_mark 0x20 good_service_net
1910 NAME: clientside_mark
1912 IFDEF: SO_MARK&&USE_LIBCAP
1914 LOC: Ip::Qos::TheConfig.nfmarkToClient
1916 Allows you to apply a Netfilter mark value to packets being transmitted
1917 on the client-side, based on an ACL.
1919 clientside_mark mark-value [!]aclname ...
1921 Example where normal_service_net uses the mark value 0x00
1922 and good_service_net uses 0x20
1924 acl normal_service_net src 10.0.0.0/24
1925 acl good_service_net src 10.0.1.0/24
1926 clientside_mark 0x00 normal_service_net
1927 clientside_mark 0x20 good_service_net
1929 Note: This feature is incompatible with qos_flows. Any mark values set here
1930 will be overwritten by mark values in qos_flows.
1937 LOC: Ip::Qos::TheConfig
1939 Allows you to select a TOS/DSCP value to mark outgoing
1940 connections with, based on where the reply was sourced. For
1941 platforms using netfilter, allows you to set a netfilter mark
1942 value instead of, or in addition to, a TOS value.
1944 TOS values really only have local significance - so you should
1945 know what you're specifying. For more information, see RFC2474,
1946 RFC2475, and RFC3260.
1948 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1949 in practice often only multiples of 4 is usable as the two rightmost bits
1950 have been redefined for use by ECN (RFC 3168 section 23.1).
1952 Mark values can be any unsigned 32-bit integer value.
1954 This setting is configured by setting the following values:
1956 tos|mark Whether to set TOS or netfilter mark values
1958 local-hit=0xFF Value to mark local cache hits.
1960 sibling-hit=0xFF Value to mark hits from sibling peers.
1962 parent-hit=0xFF Value to mark hits from parent peers.
1964 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
1965 over the preserve-miss feature (see below), unless
1966 mask is specified, in which case only the bits
1967 specified in the mask are written.
1969 The TOS variant of the following features are only possible on Linux
1970 and require your kernel to be patched with the TOS preserving ZPH
1971 patch, available from http://zph.bratcheda.org
1972 No patch is needed to preserve the netfilter mark, which will work
1973 with all variants of netfilter.
1975 disable-preserve-miss
1976 This option disables the preservation of the TOS or netfilter
1977 mark. By default, the existing TOS or netfilter mark value of
1978 the response coming from the remote server will be retained
1979 and masked with miss-mark.
1980 NOTE: in the case of a netfilter mark, the mark must be set on
1981 the connection (using the CONNMARK target) not on the packet
1985 Allows you to mask certain bits in the TOS or mark value
1986 received from the remote server, before copying the value to
1987 the TOS sent towards clients.
1988 Default for tos: 0xFF (TOS from server is not changed).
1989 Default for mark: 0xFFFFFFFF (mark from server is not changed).
1991 All of these features require the --enable-zph-qos compilation flag
1992 (enabled by default). Netfilter marking also requires the
1993 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
1994 libcap 2.09+ (--with-libcap).
1998 NAME: tcp_outgoing_address
2001 LOC: Config.accessList.outgoing_address
2003 Allows you to map requests to different outgoing IP addresses
2004 based on the username or source address of the user making
2007 tcp_outgoing_address ipaddr [[!]aclname] ...
2010 Forwarding clients with dedicated IPs for certain subnets.
2012 acl normal_service_net src 10.0.0.0/24
2013 acl good_service_net src 10.0.2.0/24
2015 tcp_outgoing_address 2001:db8::c001 good_service_net
2016 tcp_outgoing_address 10.1.0.2 good_service_net
2018 tcp_outgoing_address 2001:db8::beef normal_service_net
2019 tcp_outgoing_address 10.1.0.1 normal_service_net
2021 tcp_outgoing_address 2001:db8::1
2022 tcp_outgoing_address 10.1.0.3
2024 Processing proceeds in the order specified, and stops at first fully
2027 Squid will add an implicit IP version test to each line.
2028 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2029 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2032 NOTE: The use of this directive using client dependent ACLs is
2033 incompatible with the use of server side persistent connections. To
2034 ensure correct results it is best to set server_persistent_connections
2035 to off when using this directive in such configurations.
2037 NOTE: The use of this directive to set a local IP on outgoing TCP links
2038 is incompatible with using TPROXY to set client IP out outbound TCP links.
2039 When needing to contact peers use the no-tproxy cache_peer option and the
2040 client_dst_passthru directive re-enable normal forwarding such as this.
2044 NAME: host_verify_strict
2047 LOC: Config.onoff.hostStrictVerify
2049 Regardless of this option setting, when dealing with intercepted
2050 traffic, Squid always verifies that the destination IP address matches
2051 the Host header domain or IP (called 'authority form URL').
2053 This enforcement is performed to satisfy a MUST-level requirement in
2054 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2055 authority of the origin server or gateway given by the original URL".
2058 Squid always responds with an HTTP 409 (Conflict) error
2059 page and logs a security warning if there is no match.
2061 Squid verifies that the destination IP address matches
2062 the Host header for forward-proxy and reverse-proxy traffic
2063 as well. For those traffic types, Squid also enables the
2064 following checks, comparing the corresponding Host header
2065 and Request-URI components:
2067 * The host names (domain or IP) must be identical,
2068 but valueless or missing Host header disables all checks.
2069 For the two host names to match, both must be either IP
2072 * Port numbers must be identical, but if a port is missing
2073 the scheme-default port is assumed.
2076 When set to OFF (the default):
2077 Squid allows suspicious requests to continue but logs a
2078 security warning and blocks caching of the response.
2080 * Forward-proxy traffic is not checked at all.
2082 * Reverse-proxy traffic is not checked at all.
2084 * Intercepted traffic which passes verification is handled
2085 according to client_dst_passthru.
2087 * Intercepted requests which fail verification are sent
2088 to the client original destination instead of DIRECT.
2089 This overrides 'client_dst_passthru off'.
2091 For now suspicious intercepted CONNECT requests are always
2092 responded to with an HTTP 409 (Conflict) error page.
2097 As described in CVE-2009-0801 when the Host: header alone is used
2098 to determine the destination of a request it becomes trivial for
2099 malicious scripts on remote websites to bypass browser same-origin
2100 security policy and sandboxing protections.
2102 The cause of this is that such applets are allowed to perform their
2103 own HTTP stack, in which case the same-origin policy of the browser
2104 sandbox only verifies that the applet tries to contact the same IP
2105 as from where it was loaded at the IP level. The Host: header may
2106 be different from the connected IP and approved origin.
2110 NAME: client_dst_passthru
2113 LOC: Config.onoff.client_dst_passthru
2115 With NAT or TPROXY intercepted traffic Squid may pass the request
2116 directly to the original client destination IP or seek a faster
2117 source using the HTTP Host header.
2119 Using Host to locate alternative servers can provide faster
2120 connectivity with a range of failure recovery options.
2121 But can also lead to connectivity trouble when the client and
2122 server are attempting stateful interactions unaware of the proxy.
2124 This option (on by default) prevents alternative DNS entries being
2125 located to send intercepted traffic DIRECT to an origin server.
2126 The clients original destination IP and port will be used instead.
2128 Regardless of this option setting, when dealing with intercepted
2129 traffic Squid will verify the Host: header and any traffic which
2130 fails Host verification will be treated as if this option were ON.
2132 see host_verify_strict for details on the verification process.
2137 -----------------------------------------------------------------------------
2140 NAME: ssl_unclean_shutdown
2144 LOC: Config.SSL.unclean_shutdown
2146 Some browsers (especially MSIE) bugs out on SSL shutdown
2153 LOC: Config.SSL.ssl_engine
2156 The OpenSSL engine to use. You will need to set this if you
2157 would like to use hardware SSL acceleration for example.
2160 NAME: sslproxy_client_certificate
2163 LOC: Config.ssl_client.cert
2166 Client SSL Certificate to use when proxying https:// URLs
2169 NAME: sslproxy_client_key
2172 LOC: Config.ssl_client.key
2175 Client SSL Key to use when proxying https:// URLs
2178 NAME: sslproxy_version
2181 LOC: Config.ssl_client.version
2184 SSL version level to use when proxying https:// URLs
2186 The versions of SSL/TLS supported:
2188 1 automatic (default)
2196 NAME: sslproxy_options
2199 LOC: Config.ssl_client.options
2202 SSL implementation options to use when proxying https:// URLs
2204 The most important being:
2206 NO_SSLv2 Disallow the use of SSLv2
2207 NO_SSLv3 Disallow the use of SSLv3
2208 NO_TLSv1 Disallow the use of TLSv1.0
2209 NO_TLSv1_1 Disallow the use of TLSv1.1
2210 NO_TLSv1_2 Disallow the use of TLSv1.2
2212 Always create a new key when using temporary/ephemeral
2215 Disable use of RFC5077 session tickets. Some servers
2216 may have problems understanding the TLS extension due
2217 to ambiguous specification in RFC4507.
2218 ALL Enable various bug workarounds suggested as "harmless"
2219 by OpenSSL. Be warned that this may reduce SSL/TLS
2220 strength to some attacks.
2222 See the OpenSSL SSL_CTX_set_options documentation for a
2223 complete list of possible options.
2226 NAME: sslproxy_cipher
2229 LOC: Config.ssl_client.cipher
2232 SSL cipher list to use when proxying https:// URLs
2234 Colon separated list of supported ciphers.
2237 NAME: sslproxy_cafile
2240 LOC: Config.ssl_client.cafile
2243 file containing CA certificates to use when verifying server
2244 certificates while proxying https:// URLs
2247 NAME: sslproxy_capath
2250 LOC: Config.ssl_client.capath
2253 directory containing CA certificates to use when verifying
2254 server certificates while proxying https:// URLs
2259 TYPE: sslproxy_ssl_bump
2260 LOC: Config.accessList.ssl_bump
2263 This option is consulted when a CONNECT request is received on
2264 an http_port (or a new connection is intercepted at an
2265 https_port), provided that port was configured with an ssl-bump
2266 flag. The subsequent data on the connection is either treated as
2267 HTTPS and decrypted OR tunneled at TCP level without decryption,
2268 depending on the first bumping "mode" which ACLs match.
2270 ssl_bump <mode> [!]acl ...
2272 The following bumping modes are supported:
2275 Allow bumping of the connection. Establish a secure connection
2276 with the client first, then connect to the server. This old mode
2277 does not allow Squid to mimic server SSL certificate and does
2278 not work with intercepted SSL connections.
2281 Allow bumping of the connection. Establish a secure connection
2282 with the server first, then establish a secure connection with
2283 the client, using a mimicked server certificate. Works with both
2284 CONNECT requests and intercepted SSL connections.
2287 Become a TCP tunnel without decoding the connection.
2288 Works with both CONNECT requests and intercepted SSL
2289 connections. This is the default behavior when no
2290 ssl_bump option is given or no ssl_bump ACLs match.
2292 By default, no connections are bumped.
2294 The first matching ssl_bump option wins. If no ACLs match, the
2295 connection is not bumped. Unlike most allow/deny ACL lists, ssl_bump
2296 does not have an implicit "negate the last given option" rule. You
2297 must make that rule explicit if you convert old ssl_bump allow/deny
2298 rules that rely on such an implicit rule.
2300 This clause supports both fast and slow acl types.
2301 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2303 See also: http_port ssl-bump, https_port ssl-bump
2306 # Example: Bump all requests except those originating from
2307 # localhost and those going to example.com.
2309 acl broken_sites dstdomain .example.com
2310 ssl_bump none localhost
2311 ssl_bump none broken_sites
2312 ssl_bump server-first all
2315 NAME: sslproxy_flags
2318 LOC: Config.ssl_client.flags
2321 Various flags modifying the use of SSL while proxying https:// URLs:
2322 DONT_VERIFY_PEER Accept certificates that fail verification.
2323 For refined control, see sslproxy_cert_error.
2324 NO_DEFAULT_CA Don't use the default CA list built in
2328 NAME: sslproxy_cert_error
2331 LOC: Config.ssl_client.cert_error
2334 Use this ACL to bypass server certificate validation errors.
2336 For example, the following lines will bypass all validation errors
2337 when talking to servers for example.com. All other
2338 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2340 acl BrokenButTrustedServers dstdomain example.com
2341 sslproxy_cert_error allow BrokenButTrustedServers
2342 sslproxy_cert_error deny all
2344 This clause only supports fast acl types.
2345 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2346 Using slow acl types may result in server crashes
2348 Without this option, all server certificate validation errors
2349 terminate the transaction. Bypassing validation errors is dangerous
2350 because an error usually implies that the server cannot be trusted and
2351 the connection may be insecure.
2353 See also: sslproxy_flags and DONT_VERIFY_PEER.
2355 Default setting: sslproxy_cert_error deny all
2358 NAME: sslproxy_cert_sign
2361 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2362 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2363 POSTSCRIPTUM: signTrusted all
2364 TYPE: sslproxy_cert_sign
2365 LOC: Config.ssl_client.cert_sign
2368 sslproxy_cert_sign <signing algorithm> acl ...
2370 The following certificate signing algorithms are supported:
2372 Sign using the configured CA certificate which is usually
2373 placed in and trusted by end-user browsers. This is the
2374 default for trusted origin server certificates.
2376 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2377 This is the default for untrusted origin server certificates
2378 that are not self-signed (see ssl::certUntrusted).
2380 Sign using a self-signed certificate with the right CN to
2381 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2382 browser. This is the default for self-signed origin server
2383 certificates (see ssl::certSelfSigned).
2385 This clause only supports fast acl types.
2387 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2388 signing algorithm to generate the certificate and ignores all
2389 subsequent sslproxy_cert_sign options (the first match wins). If no
2390 acl(s) match, the default signing algorithm is determined by errors
2391 detected when obtaining and validating the origin server certificate.
2393 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2394 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2395 CONNECT request that carries a domain name. In all other cases (CONNECT
2396 to an IP address or an intercepted SSL connection), Squid cannot detect
2397 the domain mismatch at certificate generation time when
2398 bump-server-first is used.
2401 NAME: sslproxy_cert_adapt
2404 TYPE: sslproxy_cert_adapt
2405 LOC: Config.ssl_client.cert_adapt
2408 sslproxy_cert_adapt <adaptation algorithm> acl ...
2410 The following certificate adaptation algorithms are supported:
2412 Sets the "Not After" property to the "Not After" property of
2413 the CA certificate used to sign generated certificates.
2415 Sets the "Not Before" property to the "Not Before" property of
2416 the CA certificate used to sign generated certificates.
2417 setCommonName or setCommonName{CN}
2418 Sets Subject.CN property to the host name specified as a
2419 CN parameter or, if no explicit CN parameter was specified,
2420 extracted from the CONNECT request. It is a misconfiguration
2421 to use setCommonName without an explicit parameter for
2422 intercepted or tproxied SSL connections.
2424 This clause only supports fast acl types.
2426 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2427 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2428 corresponding adaptation algorithm to generate the certificate and
2429 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2430 group (i.e., the first match wins within each algorithm group). If no
2431 acl(s) match, the default mimicking action takes place.
2433 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2434 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2435 CONNECT request that carries a domain name. In all other cases (CONNECT
2436 to an IP address or an intercepted SSL connection), Squid cannot detect
2437 the domain mismatch at certificate generation time when
2438 bump-server-first is used.
2441 NAME: sslpassword_program
2444 LOC: Config.Program.ssl_password
2447 Specify a program used for entering SSL key passphrases
2448 when using encrypted SSL certificate keys. If not specified
2449 keys must either be unencrypted, or Squid started with the -N
2450 option to allow it to query interactively for the passphrase.
2452 The key file name is given as argument to the program allowing
2453 selection of the right password if you have multiple encrypted
2458 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2459 -----------------------------------------------------------------------------
2462 NAME: sslcrtd_program
2465 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2466 LOC: Ssl::TheConfig.ssl_crtd
2468 Specify the location and options of the executable for ssl_crtd process.
2469 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2470 For more information use:
2471 @DEFAULT_SSL_CRTD@ -h
2474 NAME: sslcrtd_children
2475 TYPE: HelperChildConfig
2477 DEFAULT: 32 startup=5 idle=1
2478 LOC: Ssl::TheConfig.ssl_crtdChildren
2480 The maximum number of processes spawn to service ssl server.
2481 The maximum this may be safely set to is 32.
2483 The startup= and idle= options allow some measure of skew in your
2488 Sets the minimum number of processes to spawn when Squid
2489 starts or reconfigures. When set to zero the first request will
2490 cause spawning of the first child process to handle it.
2492 Starting too few children temporary slows Squid under load while it
2493 tries to spawn enough additional processes to cope with traffic.
2497 Sets a minimum of how many processes Squid is to try and keep available
2498 at all times. When traffic begins to rise above what the existing
2499 processes can handle this many more will be spawned up to the maximum
2500 configured. A minimum setting of 1 is required.
2502 You must have at least one ssl_crtd process.
2505 NAME: sslcrtvalidator_program
2509 LOC: Ssl::TheConfig.ssl_crt_validator
2511 Specify the location and options of the executable for ssl_crt_validator
2513 sslcrtvalidator_program [ttl=n] [cache=n] path ...
2516 ttl=n TTL in seconds for cached results.The default is 60 secs
2517 cache=n limit the result cache size. The default value is 2048
2520 NAME: sslcrtvalidator_children
2521 TYPE: HelperChildConfig
2523 DEFAULT: 32 startup=5 idle=1 concurrency=1
2524 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2526 The maximum number of processes spawn to service ssl server.
2527 The maximum this may be safely set to is 32.
2529 The startup= and idle= options allow some measure of skew in your
2534 Sets the minimum number of processes to spawn when Squid
2535 starts or reconfigures. When set to zero the first request will
2536 cause spawning of the first child process to handle it.
2538 Starting too few children temporary slows Squid under load while it
2539 tries to spawn enough additional processes to cope with traffic.
2543 Sets a minimum of how many processes Squid is to try and keep available
2544 at all times. When traffic begins to rise above what the existing
2545 processes can handle this many more will be spawned up to the maximum
2546 configured. A minimum setting of 1 is required.
2550 The number of requests each certificate validator helper can handle in
2551 parallel. Defaults to 0 which indicates the certficate validator
2552 is a old-style single threaded redirector.
2554 When this directive is set to a value >= 1 then the protocol
2555 used to communicate with the helper is modified to include
2556 a request ID in front of the request/response. The request
2557 ID from the request must be echoed back with the response
2560 You must have at least one ssl_crt_validator process.
2564 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2565 -----------------------------------------------------------------------------
2573 To specify other caches in a hierarchy, use the format:
2575 cache_peer hostname type http-port icp-port [options]
2580 # hostname type port port options
2581 # -------------------- -------- ----- ----- -----------
2582 cache_peer parent.foo.net parent 3128 3130 default
2583 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2584 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2585 cache_peer example.com parent 80 0 default
2586 cache_peer cdn.example.com sibling 3128 0
2588 type: either 'parent', 'sibling', or 'multicast'.
2590 proxy-port: The port number where the peer accept HTTP requests.
2591 For other Squid proxies this is usually 3128
2592 For web servers this is usually 80
2594 icp-port: Used for querying neighbor caches about objects.
2595 Set to 0 if the peer does not support ICP or HTCP.
2596 See ICP and HTCP options below for additional details.
2599 ==== ICP OPTIONS ====
2601 You MUST also set icp_port and icp_access explicitly when using these options.
2602 The defaults will prevent peer traffic using ICP.
2605 no-query Disable ICP queries to this neighbor.
2608 Indicates the named peer is a member of a multicast group.
2609 ICP queries will not be sent directly to the peer, but ICP
2610 replies will be accepted from it.
2612 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2613 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2616 To only send ICP queries to this neighbor infrequently.
2617 This is used to keep the neighbor round trip time updated
2618 and is usually used in conjunction with weighted-round-robin.
2621 ==== HTCP OPTIONS ====
2623 You MUST also set htcp_port and htcp_access explicitly when using these options.
2624 The defaults will prevent peer traffic using HTCP.
2627 htcp Send HTCP, instead of ICP, queries to the neighbor.
2628 You probably also want to set the "icp-port" to 4827
2629 instead of 3130. This directive accepts a comma separated
2630 list of options described below.
2632 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2634 htcp=no-clr Send HTCP to the neighbor but without
2635 sending any CLR requests. This cannot be used with
2638 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2639 This cannot be used with no-clr.
2642 Send HTCP to the neighbor including CLRs but only when
2643 they do not result from PURGE requests.
2646 Forward any HTCP CLR requests this proxy receives to the peer.
2649 ==== PEER SELECTION METHODS ====
2651 The default peer selection method is ICP, with the first responding peer
2652 being used as source. These options can be used for better load balancing.
2655 default This is a parent cache which can be used as a "last-resort"
2656 if a peer cannot be located by any of the peer-selection methods.
2657 If specified more than once, only the first is used.
2659 round-robin Load-Balance parents which should be used in a round-robin
2660 fashion in the absence of any ICP queries.
2661 weight=N can be used to add bias.
2663 weighted-round-robin
2664 Load-Balance parents which should be used in a round-robin
2665 fashion with the frequency of each parent being based on the
2666 round trip time. Closer parents are used more often.
2667 Usually used for background-ping parents.
2668 weight=N can be used to add bias.
2670 carp Load-Balance parents which should be used as a CARP array.
2671 The requests will be distributed among the parents based on the
2672 CARP load balancing hash function based on their weight.
2674 userhash Load-balance parents based on the client proxy_auth or ident username.
2676 sourcehash Load-balance parents based on the client source IP.
2679 To be used only for cache peers of type "multicast".
2680 ALL members of this multicast group have "sibling"
2681 relationship with it, not "parent". This is to a multicast
2682 group when the requested object would be fetched only from
2683 a "parent" cache, anyway. It's useful, e.g., when
2684 configuring a pool of redundant Squid proxies, being
2685 members of the same multicast group.
2688 ==== PEER SELECTION OPTIONS ====
2690 weight=N use to affect the selection of a peer during any weighted
2691 peer-selection mechanisms.
2692 The weight must be an integer; default is 1,
2693 larger weights are favored more.
2694 This option does not affect parent selection if a peering
2695 protocol is not in use.
2697 basetime=N Specify a base amount to be subtracted from round trip
2699 It is subtracted before division by weight in calculating
2700 which parent to fectch from. If the rtt is less than the
2701 base time the rtt is set to a minimal value.
2703 ttl=N Specify a TTL to use when sending multicast ICP queries
2705 Only useful when sending to a multicast group.
2706 Because we don't accept ICP replies from random
2707 hosts, you must configure other group members as
2708 peers with the 'multicast-responder' option.
2710 no-delay To prevent access to this neighbor from influencing the
2713 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2714 enabled) for this host from the specified URL rather
2715 than the Squid default location.
2718 ==== CARP OPTIONS ====
2720 carp-key=key-specification
2721 use a different key than the full URL to hash against the peer.
2722 the key-specification is a comma-separated list of the keywords
2723 scheme, host, port, path, params
2724 Order is not important.
2726 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2728 originserver Causes this parent to be contacted as an origin server.
2729 Meant to be used in accelerator setups when the peer
2733 Set the Host header of requests forwarded to this peer.
2734 Useful in accelerator setups where the server (peer)
2735 expects a certain domain name but clients may request
2736 others. ie example.com or www.example.com
2738 no-digest Disable request of cache digests.
2741 Disables requesting ICMP RTT database (NetDB).
2744 ==== AUTHENTICATION OPTIONS ====
2747 If this is a personal/workgroup proxy and your parent
2748 requires proxy authentication.
2750 Note: The string can include URL escapes (i.e. %20 for
2751 spaces). This also means % must be written as %%.
2754 Send login details received from client to this peer.
2755 Both Proxy- and WWW-Authorization headers are passed
2756 without alteration to the peer.
2757 Authentication is not required by Squid for this to work.
2759 Note: This will pass any form of authentication but
2760 only Basic auth will work through a proxy unless the
2761 connection-auth options are also used.
2763 login=PASS Send login details received from client to this peer.
2764 Authentication is not required by this option.
2766 If there are no client-provided authentication headers
2767 to pass on, but username and password are available
2768 from an external ACL user= and password= result tags
2769 they may be sent instead.
2771 Note: To combine this with proxy_auth both proxies must
2772 share the same user database as HTTP only allows for
2773 a single login (one for proxy, one for origin server).
2774 Also be warned this will expose your users proxy
2775 password to the peer. USE WITH CAUTION
2778 Send the username to the upstream cache, but with a
2779 fixed password. This is meant to be used when the peer
2780 is in another administrative domain, but it is still
2781 needed to identify each user.
2782 The star can optionally be followed by some extra
2783 information which is added to the username. This can
2784 be used to identify this proxy to the peer, similar to
2785 the login=username:password option above.
2788 If this is a personal/workgroup proxy and your parent
2789 requires a secure proxy authentication.
2790 The first principal from the default keytab or defined by
2791 the environment variable KRB5_KTNAME will be used.
2793 WARNING: The connection may transmit requests from multiple
2794 clients. Negotiate often assumes end-to-end authentication
2795 and a single-client. Which is not strictly true here.
2797 login=NEGOTIATE:principal_name
2798 If this is a personal/workgroup proxy and your parent
2799 requires a secure proxy authentication.
2800 The principal principal_name from the default keytab or
2801 defined by the environment variable KRB5_KTNAME will be
2804 WARNING: The connection may transmit requests from multiple
2805 clients. Negotiate often assumes end-to-end authentication
2806 and a single-client. Which is not strictly true here.
2808 connection-auth=on|off
2809 Tell Squid that this peer does or not support Microsoft
2810 connection oriented authentication, and any such
2811 challenges received from there should be ignored.
2812 Default is auto to automatically determine the status
2816 ==== SSL / HTTPS / TLS OPTIONS ====
2818 ssl Encrypt connections to this peer with SSL/TLS.
2820 sslcert=/path/to/ssl/certificate
2821 A client SSL certificate to use when connecting to
2824 sslkey=/path/to/ssl/key
2825 The private SSL key corresponding to sslcert above.
2826 If 'sslkey' is not specified 'sslcert' is assumed to
2827 reference a combined file containing both the
2828 certificate and the key.
2830 sslversion=1|2|3|4|5|6
2831 The SSL version to use when connecting to this peer
2832 1 = automatic (default)
2839 sslcipher=... The list of valid SSL ciphers to use when connecting
2842 ssloptions=... Specify various SSL implementation options:
2844 NO_SSLv2 Disallow the use of SSLv2
2845 NO_SSLv3 Disallow the use of SSLv3
2846 NO_TLSv1 Disallow the use of TLSv1.0
2847 NO_TLSv1_1 Disallow the use of TLSv1.1
2848 NO_TLSv1_2 Disallow the use of TLSv1.2
2850 Always create a new key when using
2851 temporary/ephemeral DH key exchanges
2852 ALL Enable various bug workarounds
2853 suggested as "harmless" by OpenSSL
2854 Be warned that this reduces SSL/TLS
2855 strength to some attacks.
2857 See the OpenSSL SSL_CTX_set_options documentation for a
2860 sslcafile=... A file containing additional CA certificates to use
2861 when verifying the peer certificate.
2863 sslcapath=... A directory containing additional CA certificates to
2864 use when verifying the peer certificate.
2866 sslcrlfile=... A certificate revocation list file to use when
2867 verifying the peer certificate.
2869 sslflags=... Specify various flags modifying the SSL implementation:
2872 Accept certificates even if they fail to
2875 Don't use the default CA list built in
2878 Don't verify the peer certificate
2879 matches the server name
2881 ssldomain= The peer name as advertised in it's certificate.
2882 Used for verifying the correctness of the received peer
2883 certificate. If not specified the peer hostname will be
2887 Enable the "Front-End-Https: On" header needed when
2888 using Squid as a SSL frontend in front of Microsoft OWA.
2889 See MS KB document Q307347 for details on this header.
2890 If set to auto the header will only be added if the
2891 request is forwarded as a https:// URL.
2894 ==== GENERAL OPTIONS ====
2897 A peer-specific connect timeout.
2898 Also see the peer_connect_timeout directive.
2900 connect-fail-limit=N
2901 How many times connecting to a peer must fail before
2902 it is marked as down. Default is 10.
2904 allow-miss Disable Squid's use of only-if-cached when forwarding
2905 requests to siblings. This is primarily useful when
2906 icp_hit_stale is used by the sibling. To extensive use
2907 of this option may result in forwarding loops, and you
2908 should avoid having two-way peerings with this option.
2909 For example to deny peer usage on requests from peer
2910 by denying cache_peer_access if the source is a peer.
2912 max-conn=N Limit the amount of connections Squid may open to this
2915 name=xxx Unique name for the peer.
2916 Required if you have multiple peers on the same host
2917 but different ports.
2918 This name can be used in cache_peer_access and similar
2919 directives to dentify the peer.
2920 Can be used by outgoing access controls through the
2923 no-tproxy Do not use the client-spoof TPROXY support when forwarding
2924 requests to this peer. Use normal address selection instead.
2926 proxy-only objects fetched from the peer will not be stored locally.
2930 NAME: cache_peer_domain cache_host_domain
2935 Use to limit the domains for which a neighbor cache will be
2938 cache_peer_domain cache-host domain [domain ...]
2939 cache_peer_domain cache-host !domain
2941 For example, specifying
2943 cache_peer_domain parent.foo.net .edu
2945 has the effect such that UDP query packets are sent to
2946 'bigserver' only when the requested object exists on a
2947 server in the .edu domain. Prefixing the domainname
2948 with '!' means the cache will be queried for objects
2951 NOTE: * Any number of domains may be given for a cache-host,
2952 either on the same or separate lines.
2953 * When multiple domains are given for a particular
2954 cache-host, the first matched domain is applied.
2955 * Cache hosts with no domain restrictions are queried
2957 * There are no defaults.
2958 * There is also a 'cache_peer_access' tag in the ACL
2962 NAME: cache_peer_access
2967 Similar to 'cache_peer_domain' but provides more flexibility by
2970 cache_peer_access cache-host allow|deny [!]aclname ...
2972 The syntax is identical to 'http_access' and the other lists of
2973 ACL elements. See the comments for 'http_access' below, or
2974 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
2977 NAME: neighbor_type_domain
2978 TYPE: hostdomaintype
2982 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
2984 Modifying the neighbor type for specific domains is now
2985 possible. You can treat some domains differently than the
2986 default neighbor type specified on the 'cache_peer' line.
2987 Normally it should only be necessary to list domains which
2988 should be treated differently because the default neighbor type
2989 applies for hostnames which do not match domains listed here.
2992 cache_peer cache.foo.org parent 3128 3130
2993 neighbor_type_domain cache.foo.org sibling .com .net
2994 neighbor_type_domain cache.foo.org sibling .au .de
2997 NAME: dead_peer_timeout
3001 LOC: Config.Timeout.deadPeer
3003 This controls how long Squid waits to declare a peer cache
3004 as "dead." If there are no ICP replies received in this
3005 amount of time, Squid will declare the peer dead and not
3006 expect to receive any further ICP replies. However, it
3007 continues to send ICP queries, and will mark the peer as
3008 alive upon receipt of the first subsequent ICP reply.
3010 This timeout also affects when Squid expects to receive ICP
3011 replies from peers. If more than 'dead_peer' seconds have
3012 passed since the last ICP reply was received, Squid will not
3013 expect to receive an ICP reply on the next query. Thus, if
3014 your time between requests is greater than this timeout, you
3015 will see a lot of requests sent DIRECT to origin servers
3016 instead of to your parents.
3019 NAME: forward_max_tries
3022 LOC: Config.forward_max_tries
3024 Controls how many different forward paths Squid will try
3025 before giving up. See also forward_timeout.
3027 NOTE: connect_retries (default: none) can make each of these
3028 possible forwarding paths be tried multiple times.
3031 NAME: hierarchy_stoplist
3034 LOC: Config.hierarchy_stoplist
3036 A list of words which, if found in a URL, cause the object to
3037 be handled directly by this cache. In other words, use this
3038 to not query neighbor caches for certain objects. You may
3039 list this option multiple times.
3042 hierarchy_stoplist cgi-bin ?
3044 Note: never_direct overrides this option.
3048 MEMORY CACHE OPTIONS
3049 -----------------------------------------------------------------------------
3056 LOC: Config.memMaxSize
3058 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3059 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3060 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3061 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3063 'cache_mem' specifies the ideal amount of memory to be used
3065 * In-Transit objects
3067 * Negative-Cached objects
3069 Data for these objects are stored in 4 KB blocks. This
3070 parameter specifies the ideal upper limit on the total size of
3071 4 KB blocks allocated. In-Transit objects take the highest
3074 In-transit objects have priority over the others. When
3075 additional space is needed for incoming data, negative-cached
3076 and hot objects will be released. In other words, the
3077 negative-cached and hot objects will fill up any unused space
3078 not needed for in-transit objects.
3080 If circumstances require, this limit will be exceeded.
3081 Specifically, if your incoming request rate requires more than
3082 'cache_mem' of memory to hold in-transit objects, Squid will
3083 exceed this limit to satisfy the new requests. When the load
3084 decreases, blocks will be freed until the high-water mark is
3085 reached. Thereafter, blocks will be used to store hot
3088 If shared memory caching is enabled, Squid does not use the shared
3089 cache space for in-transit objects, but they still consume as much
3090 local memory as they need. For more details about the shared memory
3091 cache, see memory_cache_shared.
3094 NAME: maximum_object_size_in_memory
3098 LOC: Config.Store.maxInMemObjSize
3100 Objects greater than this size will not be attempted to kept in
3101 the memory cache. This should be set high enough to keep objects
3102 accessed frequently in memory to improve performance whilst low
3103 enough to keep larger objects from hoarding cache_mem.
3106 NAME: memory_cache_shared
3109 LOC: Config.memShared
3111 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3113 Controls whether the memory cache is shared among SMP workers.
3115 The shared memory cache is meant to occupy cache_mem bytes and replace
3116 the non-shared memory cache, although some entities may still be
3117 cached locally by workers for now (e.g., internal and in-transit
3118 objects may be served from a local memory cache even if shared memory
3119 caching is enabled).
3121 By default, the memory cache is shared if and only if all of the
3122 following conditions are satisfied: Squid runs in SMP mode with
3123 multiple workers, cache_mem is positive, and Squid environment
3124 supports required IPC primitives (e.g., POSIX shared memory segments
3125 and GCC-style atomic operations).
3127 To avoid blocking locks, shared memory uses opportunistic algorithms
3128 that do not guarantee that every cachable entity that could have been
3129 shared among SMP workers will actually be shared.
3131 Currently, entities exceeding 32KB in size cannot be shared.
3134 NAME: memory_cache_mode
3139 Controls which objects to keep in the memory cache (cache_mem)
3141 always Keep most recently fetched objects in memory (default)
3143 disk Only disk cache hits are kept in memory, which means
3144 an object must first be cached on disk and then hit
3145 a second time before cached in memory.
3147 network Only objects fetched from network is kept in memory
3150 NAME: memory_replacement_policy
3152 LOC: Config.memPolicy
3155 The memory replacement policy parameter determines which
3156 objects are purged from memory when memory space is needed.
3158 See cache_replacement_policy for details.
3163 -----------------------------------------------------------------------------
3166 NAME: cache_replacement_policy
3168 LOC: Config.replPolicy
3171 The cache replacement policy parameter determines which
3172 objects are evicted (replaced) when disk space is needed.
3174 lru : Squid's original list based LRU policy
3175 heap GDSF : Greedy-Dual Size Frequency
3176 heap LFUDA: Least Frequently Used with Dynamic Aging
3177 heap LRU : LRU policy implemented using a heap
3179 Applies to any cache_dir lines listed below this.
3181 The LRU policies keeps recently referenced objects.
3183 The heap GDSF policy optimizes object hit rate by keeping smaller
3184 popular objects in cache so it has a better chance of getting a
3185 hit. It achieves a lower byte hit rate than LFUDA though since
3186 it evicts larger (possibly popular) objects.
3188 The heap LFUDA policy keeps popular objects in cache regardless of
3189 their size and thus optimizes byte hit rate at the expense of
3190 hit rate since one large, popular object will prevent many
3191 smaller, slightly less popular objects from being cached.
3193 Both policies utilize a dynamic aging mechanism that prevents
3194 cache pollution that can otherwise occur with frequency-based
3195 replacement policies.
3197 NOTE: if using the LFUDA replacement policy you should increase
3198 the value of maximum_object_size above its default of 4 MB to
3199 to maximize the potential byte hit rate improvement of LFUDA.
3201 For more information about the GDSF and LFUDA cache replacement
3202 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3203 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3209 LOC: Config.cacheSwap
3213 cache_dir Type Directory-Name Fs-specific-data [options]
3215 You can specify multiple cache_dir lines to spread the
3216 cache among different disk partitions.
3218 Type specifies the kind of storage system to use. Only "ufs"
3219 is built by default. To enable any of the other storage systems
3220 see the --enable-storeio configure option.
3222 'Directory' is a top-level directory where cache swap
3223 files will be stored. If you want to use an entire disk
3224 for caching, this can be the mount-point directory.
3225 The directory must exist and be writable by the Squid
3226 process. Squid will NOT create this directory for you.
3228 In SMP configurations, cache_dir must not precede the workers option
3229 and should use configuration macros or conditionals to give each
3230 worker interested in disk caching a dedicated cache directory.
3234 "ufs" is the old well-known Squid storage format that has always
3237 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3239 'Mbytes' is the amount of disk space (MB) to use under this
3240 directory. The default is 100 MB. Change this to suit your
3241 configuration. Do NOT put the size of your disk drive here.
3242 Instead, if you want Squid to use the entire disk drive,
3243 subtract 20% and use that value.
3245 'L1' is the number of first-level subdirectories which
3246 will be created under the 'Directory'. The default is 16.
3248 'L2' is the number of second-level subdirectories which
3249 will be created under each first-level directory. The default
3252 The aufs store type:
3254 "aufs" uses the same storage format as "ufs", utilizing
3255 POSIX-threads to avoid blocking the main Squid process on
3256 disk-I/O. This was formerly known in Squid as async-io.
3258 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3260 see argument descriptions under ufs above
3262 The diskd store type:
3264 "diskd" uses the same storage format as "ufs", utilizing a
3265 separate process to avoid blocking the main Squid process on
3268 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3270 see argument descriptions under ufs above
3272 Q1 specifies the number of unacknowledged I/O requests when Squid
3273 stops opening new files. If this many messages are in the queues,
3274 Squid won't open new files. Default is 64
3276 Q2 specifies the number of unacknowledged messages when Squid
3277 starts blocking. If this many messages are in the queues,
3278 Squid blocks until it receives some replies. Default is 72
3280 When Q1 < Q2 (the default), the cache directory is optimized
3281 for lower response time at the expense of a decrease in hit
3282 ratio. If Q1 > Q2, the cache directory is optimized for
3283 higher hit ratio at the expense of an increase in response
3286 The rock store type:
3288 cache_dir rock Directory-Name Mbytes <max-size=bytes> [options]
3290 The Rock Store type is a database-style storage. All cached
3291 entries are stored in a "database" file, using fixed-size slots,
3292 one entry per slot. The database size is specified in MB. The
3293 slot size is specified in bytes using the max-size option. See
3294 below for more info on the max-size option.
3296 swap-timeout=msec: Squid will not start writing a miss to or
3297 reading a hit from disk if it estimates that the swap operation
3298 will take more than the specified number of milliseconds. By
3299 default and when set to zero, disables the disk I/O time limit
3300 enforcement. Ignored when using blocking I/O module because
3301 blocking synchronous I/O does not allow Squid to estimate the
3302 expected swap wait time.
3304 max-swap-rate=swaps/sec: Artificially limits disk access using
3305 the specified I/O rate limit. Swap out requests that
3306 would cause the average I/O rate to exceed the limit are
3307 delayed. Individual swap in requests (i.e., hits or reads) are
3308 not delayed, but they do contribute to measured swap rate and
3309 since they are placed in the same FIFO queue as swap out
3310 requests, they may wait longer if max-swap-rate is smaller.
3311 This is necessary on file systems that buffer "too
3312 many" writes and then start blocking Squid and other processes
3313 while committing those writes to disk. Usually used together
3314 with swap-timeout to avoid excessive delays and queue overflows
3315 when disk demand exceeds available disk "bandwidth". By default
3316 and when set to zero, disables the disk I/O rate limit
3317 enforcement. Currently supported by IpcIo module only.
3320 The coss store type:
3322 NP: COSS filesystem in Squid-3 has been deemed too unstable for
3323 production use and has thus been removed from this release.
3324 We hope that it can be made usable again soon.
3326 block-size=n defines the "block size" for COSS cache_dir's.
3327 Squid uses file numbers as block numbers. Since file numbers
3328 are limited to 24 bits, the block size determines the maximum
3329 size of the COSS partition. The default is 512 bytes, which
3330 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
3331 you should not change the coss block size after Squid
3332 has written some objects to the cache_dir.
3334 The coss file store has changed from 2.5. Now it uses a file
3335 called 'stripe' in the directory names in the config - and
3336 this will be created by squid -z.
3340 no-store, no new objects should be stored to this cache_dir
3342 min-size=n, refers to the min object size in bytes this cache_dir
3343 will accept. It's used to restrict a cache_dir to only store
3344 large objects (e.g. aufs) while other storedirs are optimized
3345 for smaller objects (e.g. COSS). Defaults to 0.
3347 max-size=n, refers to the max object size in bytes this cache_dir
3348 supports. It is used to select the cache_dir to store the object.
3349 Note: To make optimal use of the max-size limits you should order
3350 the cache_dir lines with the smallest max-size value first and the
3351 ones with no max-size specification last.
3353 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
3354 which can be changed with the --with-coss-membuf-size=N configure
3358 # Uncomment and adjust the following to add a disk cache directory.
3359 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3363 NAME: store_dir_select_algorithm
3365 LOC: Config.store_dir_select_algorithm
3368 Set this to 'round-robin' as an alternative.
3371 NAME: max_open_disk_fds
3373 LOC: Config.max_open_disk_fds
3376 To avoid having disk as the I/O bottleneck Squid can optionally
3377 bypass the on-disk cache if more than this amount of disk file
3378 descriptors are open.
3380 A value of 0 indicates no limit.
3383 NAME: minimum_object_size
3387 LOC: Config.Store.minObjectSize
3389 Objects smaller than this size will NOT be saved on disk. The
3390 value is specified in kilobytes, and the default is 0 KB, which
3391 means there is no minimum.
3394 NAME: maximum_object_size
3398 LOC: Config.Store.maxObjectSize
3400 The default limit on size of objects stored to disk.
3401 This size is used for cache_dir where max-size is not set.
3402 The value is specified in bytes, and the default is 4 MB.
3404 If you wish to get a high BYTES hit ratio, you should probably
3405 increase this (one 32 MB object hit counts for 3200 10KB
3408 If you wish to increase hit ratio more than you want to
3409 save bandwidth you should leave this low.
3411 NOTE: if using the LFUDA replacement policy you should increase
3412 this value to maximize the byte hit rate improvement of LFUDA!
3413 See replacement_policy below for a discussion of this policy.
3416 NAME: cache_swap_low
3417 COMMENT: (percent, 0-100)
3420 LOC: Config.Swap.lowWaterMark
3423 NAME: cache_swap_high
3424 COMMENT: (percent, 0-100)
3427 LOC: Config.Swap.highWaterMark
3430 The low- and high-water marks for cache object replacement.
3431 Replacement begins when the swap (disk) usage is above the
3432 low-water mark and attempts to maintain utilization near the
3433 low-water mark. As swap utilization gets close to high-water
3434 mark object eviction becomes more aggressive. If utilization is
3435 close to the low-water mark less replacement is done each time.
3437 Defaults are 90% and 95%. If you have a large cache, 5% could be
3438 hundreds of MB. If this is the case you may wish to set these
3439 numbers closer together.
3444 -----------------------------------------------------------------------------
3454 logformat <name> <format specification>
3456 Defines an access log format.
3458 The <format specification> is a string with embedded % format codes
3460 % format codes all follow the same basic structure where all but
3461 the formatcode is optional. Output strings are automatically escaped
3462 as required according to their context and the output format
3463 modifiers are usually not needed, but can be specified if an explicit
3464 output format is desired.
3466 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3468 " output in quoted string format
3469 [ output in squid text log format as used by log_mime_hdrs
3470 # output in URL quoted format
3475 width minimum and/or maximum field width:
3476 [width_min][.width_max]
3477 When minimum starts with 0, the field is zero-padded.
3478 String values exceeding maximum width are truncated.
3480 {arg} argument such as header name etc
3484 % a literal % character
3485 sn Unique sequence number per log line entry
3486 err_code The ID of an error response served by Squid or
3487 a similar internal error identifier.
3488 err_detail Additional err_code-dependent error information.
3489 note The meta header specified by the argument. Also
3490 logs the adaptation meta headers set by the
3491 adaptation_meta configuration parameter.
3492 If no argument given all meta headers logged.
3494 Connection related format codes:
3496 >a Client source IP address
3498 >p Client source port
3499 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3500 >la Local IP address the client connected to
3501 >lp Local port number the client connected to
3503 la Local listening IP address the client connection was connected to.
3504 lp Local listening port number the client connection was connected to.
3506 <a Server IP address of the last server or peer connection
3507 <A Server FQDN or peer name
3508 <p Server port number of the last server or peer connection
3509 <la Local IP address of the last server or peer connection
3510 <lp Local port number of the last server or peer connection
3512 Time related format codes:
3514 ts Seconds since epoch
3515 tu subsecond time (milliseconds)
3516 tl Local time. Optional strftime format argument
3517 default %d/%b/%Y:%H:%M:%S %z
3518 tg GMT time. Optional strftime format argument
3519 default %d/%b/%Y:%H:%M:%S %z
3520 tr Response time (milliseconds)
3521 dt Total time spent making DNS lookups (milliseconds)
3523 Access Control related format codes:
3525 et Tag returned by external acl
3526 ea Log string returned by external acl
3527 un User name (any available)
3528 ul User name from authentication
3529 ue User name from external acl helper
3530 ui User name from ident
3531 us User name from SSL
3533 HTTP related format codes:
3535 [http::]>h Original request header. Optional header name argument
3536 on the format header[:[separator]element]
3537 [http::]>ha The HTTP request headers after adaptation and redirection.
3538 Optional header name argument as for >h
3539 [http::]<h Reply header. Optional header name argument
3541 [http::]>Hs HTTP status code sent to the client
3542 [http::]<Hs HTTP status code received from the next hop
3543 [http::]<bs Number of HTTP-equivalent message body bytes
3544 received from the next hop, excluding chunked
3545 transfer encoding and control messages.
3546 Generated FTP/Gopher listings are treated as
3548 [http::]mt MIME content type
3549 [http::]rm Request method (GET/POST etc)
3550 [http::]>rm Request method from client
3551 [http::]<rm Request method sent to server or peer
3552 [http::]ru Request URL from client (historic, filtered for logging)
3553 [http::]>ru Request URL from client
3554 [http::]<ru Request URL sent to server or peer
3555 [http::]rp Request URL-Path excluding hostname
3556 [http::]>rp Request URL-Path excluding hostname from client
3557 [http::]<rp Request URL-Path excluding hostname sento to server or peer
3558 [http::]rv Request protocol version
3559 [http::]>rv Request protocol version from client
3560 [http::]<rv Request protocol version sent to server or peer
3561 [http::]<st Sent reply size including HTTP headers
3562 [http::]>st Received request size including HTTP headers. In the
3563 case of chunked requests the chunked encoding metadata
3565 [http::]>sh Received HTTP request headers size
3566 [http::]<sh Sent HTTP reply headers size
3567 [http::]st Request+Reply size including HTTP headers
3568 [http::]<sH Reply high offset sent
3569 [http::]<sS Upstream object size
3570 [http::]<pt Peer response time in milliseconds. The timer starts
3571 when the last request byte is sent to the next hop
3572 and stops when the last response byte is received.
3573 [http::]<tt Total server-side time in milliseconds. The timer
3574 starts with the first connect request (or write I/O)
3575 sent to the first selected peer. The timer stops
3576 with the last I/O with the last peer.
3578 Squid handling related format codes:
3580 Ss Squid request status (TCP_MISS etc)
3581 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3583 SSL-related format codes:
3585 ssl::bump_mode SslBump decision for the transaction:
3587 For CONNECT requests that initiated bumping of
3588 a connection and for any request received on
3589 an already bumped connection, Squid logs the
3590 corresponding SslBump mode ("server-first" or
3591 "client-first"). See the ssl_bump option for
3592 more information about these modes.
3594 A "none" token is logged for requests that
3595 triggered "ssl_bump" ACL evaluation matching
3596 either a "none" rule or no rules at all.
3598 In all other cases, a single dash ("-") is
3601 If ICAP is enabled, the following code becomes available (as
3602 well as ICAP log codes documented with the icap_log option):
3604 icap::tt Total ICAP processing time for the HTTP
3605 transaction. The timer ticks when ICAP
3606 ACLs are checked and when ICAP
3607 transaction is in progress.
3609 If adaptation is enabled the following three codes become available:
3611 adapt::<last_h The header of the last ICAP response or
3612 meta-information from the last eCAP
3613 transaction related to the HTTP transaction.
3614 Like <h, accepts an optional header name
3617 adapt::sum_trs Summed adaptation transaction response
3618 times recorded as a comma-separated list in
3619 the order of transaction start time. Each time
3620 value is recorded as an integer number,
3621 representing response time of one or more
3622 adaptation (ICAP or eCAP) transaction in
3623 milliseconds. When a failed transaction is
3624 being retried or repeated, its time is not
3625 logged individually but added to the
3626 replacement (next) transaction. See also:
3629 adapt::all_trs All adaptation transaction response times.
3630 Same as adaptation_strs but response times of
3631 individual transactions are never added
3632 together. Instead, all transaction response
3633 times are recorded individually.
3635 You can prefix adapt::*_trs format codes with adaptation
3636 service name in curly braces to record response time(s) specific
3637 to that service. For example: %{my_service}adapt::sum_trs
3639 If SSL is enabled, the following formating codes become available:
3641 %ssl::>cert_subject The Subject field of the received client
3642 SSL certificate or a dash ('-') if Squid has
3643 received an invalid/malformed certificate or
3644 no certificate at all. Consider encoding the
3645 logged value because Subject often has spaces.
3647 %ssl::>cert_issuer The Issuer field of the received client
3648 SSL certificate or a dash ('-') if Squid has
3649 received an invalid/malformed certificate or
3650 no certificate at all. Consider encoding the
3651 logged value because Issuer often has spaces.
3653 The default formats available (which do not need re-defining) are:
3655 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3656 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3657 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3658 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3659 logformat useragent %>a [%tl] "%{User-Agent}>h"
3661 NOTE: When the log_mime_hdrs directive is set to ON.
3662 The squid, common and combined formats have a safely encoded copy
3663 of the mime headers appended to each line within a pair of brackets.
3665 NOTE: The common and combined formats are not quite true to the Apache definition.
3666 The logs from Squid contain an extra status and hierarchy code appended.
3670 NAME: access_log cache_access_log
3672 LOC: Config.Log.accesslogs
3673 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3675 These files log client request activities. Has a line every HTTP or
3676 ICP request. The format is:
3677 access_log <module>:<place> [<logformat name> [acl acl ...]]
3678 access_log none [acl acl ...]]
3680 Will log to the specified module:place using the specified format (which
3681 must be defined in a logformat directive) those entries which match
3682 ALL the acl's specified (which must be defined in acl clauses).
3683 If no acl is specified, all requests will be logged to this destination.
3685 ===== Modules Currently available =====
3687 none Do not log any requests matching these ACL.
3688 Do not specify Place or logformat name.
3690 stdio Write each log line to disk immediately at the completion of
3692 Place: the filename and path to be written.
3694 daemon Very similar to stdio. But instead of writing to disk the log
3695 line is passed to a daemon helper for asychronous handling instead.
3696 Place: varies depending on the daemon.
3698 log_file_daemon Place: the file name and path to be written.
3700 syslog To log each request via syslog facility.
3701 Place: The syslog facility and priority level for these entries.
3702 Place Format: facility.priority
3704 where facility could be any of:
3705 authpriv, daemon, local0 ... local7 or user.
3707 And priority could be any of:
3708 err, warning, notice, info, debug.
3710 udp To send each log line as text data to a UDP receiver.
3711 Place: The destination host name or IP and port.
3712 Place Format: //host:port
3714 tcp To send each log line as text data to a TCP receiver.
3715 Place: The destination host name or IP and port.
3716 Place Format: //host:port
3719 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3725 LOC: Config.Log.icaplogs
3728 ICAP log files record ICAP transaction summaries, one line per
3731 The icap_log option format is:
3732 icap_log <filepath> [<logformat name> [acl acl ...]]
3733 icap_log none [acl acl ...]]
3735 Please see access_log option documentation for details. The two
3736 kinds of logs share the overall configuration approach and many
3739 ICAP processing of a single HTTP message or transaction may
3740 require multiple ICAP transactions. In such cases, multiple
3741 ICAP transaction log lines will correspond to a single access
3744 ICAP log uses logformat codes that make sense for an ICAP
3745 transaction. Header-related codes are applied to the HTTP header
3746 embedded in an ICAP server response, with the following caveats:
3747 For REQMOD, there is no HTTP response header unless the ICAP
3748 server performed request satisfaction. For RESPMOD, the HTTP
3749 request header is the header sent to the ICAP server. For
3750 OPTIONS, there are no HTTP headers.
3752 The following format codes are also available for ICAP logs:
3754 icap::<A ICAP server IP address. Similar to <A.
3756 icap::<service_name ICAP service name from the icap_service
3757 option in Squid configuration file.
3759 icap::ru ICAP Request-URI. Similar to ru.
3761 icap::rm ICAP request method (REQMOD, RESPMOD, or
3762 OPTIONS). Similar to existing rm.
3764 icap::>st Bytes sent to the ICAP server (TCP payload
3765 only; i.e., what Squid writes to the socket).
3767 icap::<st Bytes received from the ICAP server (TCP
3768 payload only; i.e., what Squid reads from
3771 icap::<bs Number of message body bytes received from the
3772 ICAP server. ICAP message body, if any, usually
3773 includes encapsulated HTTP message headers and
3774 possibly encapsulated HTTP message body. The
3775 HTTP body part is dechunked before its size is
3778 icap::tr Transaction response time (in
3779 milliseconds). The timer starts when
3780 the ICAP transaction is created and
3781 stops when the transaction is completed.
3784 icap::tio Transaction I/O time (in milliseconds). The
3785 timer starts when the first ICAP request
3786 byte is scheduled for sending. The timers
3787 stops when the last byte of the ICAP response
3790 icap::to Transaction outcome: ICAP_ERR* for all
3791 transaction errors, ICAP_OPT for OPTION
3792 transactions, ICAP_ECHO for 204
3793 responses, ICAP_MOD for message
3794 modification, and ICAP_SAT for request
3795 satisfaction. Similar to Ss.
3797 icap::Hs ICAP response status code. Similar to Hs.
3799 icap::>h ICAP request header(s). Similar to >h.
3801 icap::<h ICAP response header(s). Similar to <h.
3803 The default ICAP log format, which can be used without an explicit
3804 definition, is called icap_squid:
3806 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3808 See also: logformat, log_icap, and %adapt::<last_h
3811 NAME: logfile_daemon
3813 DEFAULT: @DEFAULT_LOGFILED@
3814 LOC: Log::TheConfig.logfile_daemon
3816 Specify the path to the logfile-writing daemon. This daemon is
3817 used to write the access and store logs, if configured.
3819 Squid sends a number of commands to the log daemon:
3820 L<data>\n - logfile data
3825 r<n>\n - set rotate count to <n>
3826 b<n>\n - 1 = buffer output, 0 = don't buffer output
3828 No responses is expected.
3833 LOC: Config.accessList.log
3835 COMMENT: allow|deny acl acl...
3837 This options allows you to control which requests gets logged
3838 to access.log (see access_log directive). Requests denied for
3839 logging will also not be accounted for in performance counters.
3841 This clause only supports fast acl types.
3842 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3848 LOC: Config.accessList.icap
3851 This options allows you to control which requests get logged
3852 to icap.log. See the icap_log directive for ICAP log details.
3855 NAME: cache_store_log
3858 LOC: Config.Log.store
3860 Logs the activities of the storage manager. Shows which
3861 objects are ejected from the cache, and which objects are
3862 saved and for how long.
3863 There are not really utilities to analyze this data, so you can safely
3864 disable it (the default).
3866 Store log uses modular logging outputs. See access_log for the list
3867 of modules supported.
3870 cache_store_log stdio:@DEFAULT_STORE_LOG@
3871 cache_store_log daemon:@DEFAULT_STORE_LOG@
3874 NAME: cache_swap_state cache_swap_log
3876 LOC: Config.Log.swap
3879 Location for the cache "swap.state" file. This index file holds
3880 the metadata of objects saved on disk. It is used to rebuild
3881 the cache during startup. Normally this file resides in each
3882 'cache_dir' directory, but you may specify an alternate
3883 pathname here. Note you must give a full filename, not just
3884 a directory. Since this is the index for the whole object
3885 list you CANNOT periodically rotate it!
3887 If %s can be used in the file name it will be replaced with a
3888 a representation of the cache_dir name where each / is replaced
3889 with '.'. This is needed to allow adding/removing cache_dir
3890 lines when cache_swap_log is being used.
3892 If have more than one 'cache_dir', and %s is not used in the name
3893 these swap logs will have names such as:
3899 The numbered extension (which is added automatically)
3900 corresponds to the order of the 'cache_dir' lines in this
3901 configuration file. If you change the order of the 'cache_dir'
3902 lines in this file, these index files will NOT correspond to
3903 the correct 'cache_dir' entry (unless you manually rename
3904 them). We recommend you do NOT use this option. It is
3905 better to keep these index files in each 'cache_dir' directory.
3908 NAME: logfile_rotate
3911 LOC: Config.Log.rotateNumber
3913 Specifies the number of logfile rotations to make when you
3914 type 'squid -k rotate'. The default is 10, which will rotate
3915 with extensions 0 through 9. Setting logfile_rotate to 0 will
3916 disable the file name rotation, but the logfiles are still closed
3917 and re-opened. This will enable you to rename the logfiles
3918 yourself just before sending the rotate signal.
3920 Note, the 'squid -k rotate' command normally sends a USR1
3921 signal to the running squid process. In certain situations
3922 (e.g. on Linux with Async I/O), USR1 is used for other
3923 purposes, so -k rotate uses another signal. It is best to get
3924 in the habit of using 'squid -k rotate' instead of 'kill -USR1
3927 Note, from Squid-3.1 this option has no effect on the cache.log,
3928 that log can be rotated separately by using debug_options
3931 NAME: emulate_httpd_log
3934 Replace this with an access_log directive using the format 'common' or 'combined'.
3937 NAME: log_ip_on_direct
3940 Remove this option from your config. To log server or peer names use %<A in the log format.
3945 DEFAULT: @DEFAULT_MIME_TABLE@
3946 LOC: Config.mimeTablePathname
3948 Pathname to Squid's MIME table. You shouldn't need to change
3949 this, but the default file contains examples and formatting
3950 information if you do.
3956 LOC: Config.onoff.log_mime_hdrs
3959 The Cache can record both the request and the response MIME
3960 headers for each HTTP transaction. The headers are encoded
3961 safely and will appear as two bracketed fields at the end of
3962 the access log (for either the native or httpd-emulated log
3963 formats). To enable this logging set log_mime_hdrs to 'on'.
3969 Replace this with an access_log directive using the format 'useragent'.
3972 NAME: referer_log referrer_log
3975 Replace this with an access_log directive using the format 'referrer'.
3980 DEFAULT: @DEFAULT_PID_FILE@
3981 LOC: Config.pidFilename
3983 A filename to write the process-id to. To disable, enter "none".
3989 Remove this option from your config. To log FQDN use %>A in the log format.
3992 NAME: client_netmask
3994 LOC: Config.Addrs.client_netmask
3997 A netmask for client addresses in logfiles and cachemgr output.
3998 Change this to protect the privacy of your cache clients.
3999 A netmask of 255.255.255.0 will log all IP's in that range with
4000 the last digit set to '0'.
4006 Use a regular access.log with ACL limiting it to MISS events.
4009 NAME: strip_query_terms
4011 LOC: Config.onoff.strip_query_terms
4014 By default, Squid strips query terms from requested URLs before
4015 logging. This protects your user's privacy.
4022 LOC: Config.onoff.buffered_logs
4024 cache.log log file is written with stdio functions, and as such
4025 it can be buffered or unbuffered. By default it will be unbuffered.
4026 Buffering it can speed up the writing slightly (though you are
4027 unlikely to need to worry unless you run with tons of debugging
4028 enabled in which case performance will suffer badly anyway..).
4031 NAME: netdb_filename
4033 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4034 LOC: Config.netdbFilename
4037 A filename where Squid stores it's netdb state between restarts.
4038 To disable, enter "none".
4042 OPTIONS FOR TROUBLESHOOTING
4043 -----------------------------------------------------------------------------
4048 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4049 LOC: Debug::cache_log
4051 Cache logging file. This is where general information about
4052 your cache's behavior goes. You can increase the amount of data
4053 logged to this file and how often its rotated with "debug_options"
4059 LOC: Debug::debugOptions
4061 Logging options are set as section,level where each source file
4062 is assigned a unique section. Lower levels result in less
4063 output, Full debugging (level 9) can result in a very large
4064 log file, so be careful.
4066 The magic word "ALL" sets debugging levels for all sections.
4067 We recommend normally running with "ALL,1".
4069 The rotate=N option can be used to keep more or less of these logs
4070 than would otherwise be kept by logfile_rotate.
4071 For most uses a single log should be enough to monitor current
4072 events affecting Squid.
4077 LOC: Config.coredump_dir
4078 DEFAULT_IF_NONE: none
4080 By default Squid leaves core files in the directory from where
4081 it was started. If you set 'coredump_dir' to a directory
4082 that exists, Squid will chdir() to that directory at startup
4083 and coredump files will be left there.
4087 # Leave coredumps in the first cache dir
4088 coredump_dir @DEFAULT_SWAP_DIR@
4094 OPTIONS FOR FTP GATEWAYING
4095 -----------------------------------------------------------------------------
4101 LOC: Config.Ftp.anon_user
4103 If you want the anonymous login password to be more informative
4104 (and enable the use of picky ftp servers), set this to something
4105 reasonable for your domain, like wwwuser@somewhere.net
4107 The reason why this is domainless by default is the
4108 request can be made on the behalf of a user in any domain,
4109 depending on how the cache is used.
4110 Some ftp server also validate the email address is valid
4111 (for example perl.com).
4117 LOC: Config.Ftp.passive
4119 If your firewall does not allow Squid to use passive
4120 connections, turn off this option.
4122 Use of ftp_epsv_all option requires this to be ON.
4128 LOC: Config.Ftp.epsv_all
4130 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4132 NATs may be able to put the connection on a "fast path" through the
4133 translator, as the EPRT command will never be used and therefore,
4134 translation of the data portion of the segments will never be needed.
4136 When a client only expects to do two-way FTP transfers this may be
4138 If squid finds that it must do a three-way FTP transfer after issuing
4139 an EPSV ALL command, the FTP session will fail.
4141 If you have any doubts about this option do not use it.
4142 Squid will nicely attempt all other connection methods.
4144 Requires ftp_passive to be ON (default) for any effect.
4150 LOC: Config.Ftp.epsv
4152 FTP Protocol extensions permit the use of a special "EPSV" command.
4154 NATs may be able to put the connection on a "fast path" through the
4155 translator using EPSV, as the EPRT command will never be used
4156 and therefore, translation of the data portion of the segments
4157 will never be needed.
4159 Turning this OFF will prevent EPSV being attempted.
4160 WARNING: Doing so will convert Squid back to the old behavior with all
4161 the related problems with external NAT devices/layers.
4163 Requires ftp_passive to be ON (default) for any effect.
4169 LOC: Config.Ftp.eprt
4171 FTP Protocol extensions permit the use of a special "EPRT" command.
4173 This extension provides a protocol neutral alternative to the
4174 IPv4-only PORT command. When supported it enables active FTP data
4175 channels over IPv6 and efficient NAT handling.
4177 Turning this OFF will prevent EPRT being attempted and will skip
4178 straight to using PORT for IPv4 servers.
4180 Some devices are known to not handle this extension correctly and
4181 may result in crashes. Devices which suport EPRT enough to fail
4182 cleanly will result in Squid attempting PORT anyway. This directive
4183 should only be disabled when EPRT results in device failures.
4185 WARNING: Doing so will convert Squid back to the old behavior with all
4186 the related problems with external NAT devices/layers and IPv4-only FTP.
4189 NAME: ftp_sanitycheck
4192 LOC: Config.Ftp.sanitycheck
4194 For security and data integrity reasons Squid by default performs
4195 sanity checks of the addresses of FTP data connections ensure the
4196 data connection is to the requested server. If you need to allow
4197 FTP connections to servers using another IP address for the data
4198 connection turn this off.
4201 NAME: ftp_telnet_protocol
4204 LOC: Config.Ftp.telnet
4206 The FTP protocol is officially defined to use the telnet protocol
4207 as transport channel for the control connection. However, many
4208 implementations are broken and does not respect this aspect of
4211 If you have trouble accessing files with ASCII code 255 in the
4212 path or similar problems involving this ASCII code you can
4213 try setting this directive to off. If that helps, report to the
4214 operator of the FTP server in question that their FTP server
4215 is broken and does not follow the FTP standard.
4219 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4220 -----------------------------------------------------------------------------
4225 DEFAULT: @DEFAULT_DISKD@
4226 LOC: Config.Program.diskd
4228 Specify the location of the diskd executable.
4229 Note this is only useful if you have compiled in
4230 diskd as one of the store io modules.
4233 NAME: unlinkd_program
4236 DEFAULT: @DEFAULT_UNLINKD@
4237 LOC: Config.Program.unlinkd
4239 Specify the location of the executable for file deletion process.
4242 NAME: pinger_program
4244 DEFAULT: @DEFAULT_PINGER@
4245 LOC: Config.pinger.program
4248 Specify the location of the executable for the pinger process.
4254 LOC: Config.pinger.enable
4257 Control whether the pinger is active at run-time.
4258 Enables turning ICMP pinger on and off with a simple
4259 squid -k reconfigure.
4264 OPTIONS FOR URL REWRITING
4265 -----------------------------------------------------------------------------
4268 NAME: url_rewrite_program redirect_program
4270 LOC: Config.Program.redirect
4273 Specify the location of the executable URL rewriter to use.
4274 Since they can perform almost any function there isn't one included.
4276 For each requested URL, the rewriter will receive on line with the format
4278 [channel-ID <SP>] URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kv-pairs]<NL>
4281 After processing the request the helper must reply using the following format:
4283 [channel-ID <SP>] result [<SP> kv-pairs]
4285 The result code can be:
4287 OK status=30N url="..."
4288 Redirect the URL to the one supplied in 'url='.
4289 'status=' is optional and contains the status code to send
4290 the client in Squids HTTP response. It must be one of the
4291 HTTP redirect status codes: 301, 302, 303, 307, 308.
4292 When no status is given Squid will use 302.
4294 OK rewrite-url="..."
4295 Rewrite the URL to the one supplied in 'rewrite-url='.
4296 The new URL is fetched directly by Squid and returned to
4297 the client as the response to its request.
4300 Do not change the URL.
4303 An internal error occurred in the helper, preventing
4304 a result being identified.
4307 In the future, the interface protocol will be extended with
4308 key=value pairs ("kv-pairs" shown above). Helper programs
4309 should be prepared to receive and possibly ignore additional
4310 whitespace-separated tokens on each input line.
4312 When using the concurrency= option the protocol is changed by
4313 introducing a query channel tag in front of the request/response.
4314 The query channel tag is a number between 0 and concurrency-1.
4315 This value must be echoed back unchanged to Squid as the first part
4316 of the response relating to its request.
4318 WARNING: URL re-writing ability should be avoided whenever possible.
4319 Use the URL redirect form of response instead.
4321 Re-write creates a difference in the state held by the client
4322 and server. Possibly causing confusion when the server response
4323 contains snippets of its view state. Embeded URLs, response
4324 and content Location headers, etc. are not re-written by this
4327 By default, a URL rewriter is not used.
4330 NAME: url_rewrite_children redirect_children
4331 TYPE: HelperChildConfig
4332 DEFAULT: 20 startup=0 idle=1 concurrency=0
4333 LOC: Config.redirectChildren
4335 The maximum number of redirector processes to spawn. If you limit
4336 it too few Squid will have to wait for them to process a backlog of
4337 URLs, slowing it down. If you allow too many they will use RAM
4338 and other system resources noticably.
4340 The startup= and idle= options allow some measure of skew in your
4345 Sets a minimum of how many processes are to be spawned when Squid
4346 starts or reconfigures. When set to zero the first request will
4347 cause spawning of the first child process to handle it.
4349 Starting too few will cause an initial slowdown in traffic as Squid
4350 attempts to simultaneously spawn enough processes to cope.
4354 Sets a minimum of how many processes Squid is to try and keep available
4355 at all times. When traffic begins to rise above what the existing
4356 processes can handle this many more will be spawned up to the maximum
4357 configured. A minimum setting of 1 is required.
4361 The number of requests each redirector helper can handle in
4362 parallel. Defaults to 0 which indicates the redirector
4363 is a old-style single threaded redirector.
4365 When this directive is set to a value >= 1 then the protocol
4366 used to communicate with the helper is modified to include
4367 an ID in front of the request/response. The ID from the request
4368 must be echoed back with the response to that request.
4371 NAME: url_rewrite_host_header redirect_rewrites_host_header
4374 LOC: Config.onoff.redir_rewrites_host
4376 To preserve same-origin security policies in browsers and
4377 prevent Host: header forgery by redirectors Squid rewrites
4378 any Host: header in redirected requests.
4380 If you are running an accelerator this may not be a wanted
4381 effect of a redirector. This directive enables you disable
4382 Host: alteration in reverse-proxy traffic.
4384 WARNING: Entries are cached on the result of the URL rewriting
4385 process, so be careful if you have domain-virtual hosts.
4387 WARNING: Squid and other software verifies the URL and Host
4388 are matching, so be careful not to relay through other proxies
4389 or inspecting firewalls with this disabled.
4392 NAME: url_rewrite_access redirector_access
4395 LOC: Config.accessList.redirector
4397 If defined, this access list specifies which requests are
4398 sent to the redirector processes. By default all requests
4401 This clause supports both fast and slow acl types.
4402 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4405 NAME: url_rewrite_bypass redirector_bypass
4407 LOC: Config.onoff.redirector_bypass
4410 When this is 'on', a request will not go through the
4411 redirector if all redirectors are busy. If this is 'off'
4412 and the redirector queue grows too large, Squid will exit
4413 with a FATAL error and ask you to increase the number of
4414 redirectors. You should only enable this if the redirectors
4415 are not critical to your caching system. If you use
4416 redirectors for access control, and you enable this option,
4417 users may have access to pages they should not
4418 be allowed to request.
4422 OPTIONS FOR STORE ID
4423 -----------------------------------------------------------------------------
4426 NAME: store_id_program storeurl_rewrite_program
4428 LOC: Config.Program.store_id
4431 Specify the location of the executable StoreID helper to use.
4432 Since they can perform almost any function there isn't one included.
4434 For each requested URL, the helper will receive one line with the format
4436 [channel-ID <SP>] URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kv-pairs]<NL>
4439 After processing the request the helper must reply using the following format:
4441 [channel-ID <SP>] result [<SP> kv-pairs]
4443 The result code can be:
4446 Use the StoreID supplied in 'store-id='.
4449 The default is to use HTTP request URL as the store ID.
4452 An internal error occured in the helper, preventing
4453 a result being identified.
4456 Helper programs should be prepared to receive and possibly ignore additional
4457 kv-pairs with keys they do not support.
4459 When using the concurrency= option the protocol is changed by
4460 introducing a query channel tag in front of the request/response.
4461 The query channel tag is a number between 0 and concurrency-1.
4462 This value must be echoed back unchanged to Squid as the first part
4463 of the response relating to its request.
4465 NOTE: when using StoreID refresh_pattern will apply to the StoreID
4466 returned from the helper and not the URL.
4468 WARNING: Wrong StoreID value returned by a careless helper may result
4469 in the wrong cached response returned to the user.
4471 By default, a StoreID helper is not used.
4474 NAME: store_id_children storeurl_rewrite_children
4475 TYPE: HelperChildConfig
4476 DEFAULT: 20 startup=0 idle=1 concurrency=0
4477 LOC: Config.storeIdChildren
4479 The maximum number of StoreID helper processes to spawn. If you limit
4480 it too few Squid will have to wait for them to process a backlog of
4481 requests, slowing it down. If you allow too many they will use RAM
4482 and other system resources noticably.
4484 The startup= and idle= options allow some measure of skew in your
4489 Sets a minimum of how many processes are to be spawned when Squid
4490 starts or reconfigures. When set to zero the first request will
4491 cause spawning of the first child process to handle it.
4493 Starting too few will cause an initial slowdown in traffic as Squid
4494 attempts to simultaneously spawn enough processes to cope.
4498 Sets a minimum of how many processes Squid is to try and keep available
4499 at all times. When traffic begins to rise above what the existing
4500 processes can handle this many more will be spawned up to the maximum
4501 configured. A minimum setting of 1 is required.
4505 The number of requests each storeID helper can handle in
4506 parallel. Defaults to 0 which indicates the helper
4507 is a old-style single threaded program.
4509 When this directive is set to a value >= 1 then the protocol
4510 used to communicate with the helper is modified to include
4511 an ID in front of the request/response. The ID from the request
4512 must be echoed back with the response to that request.
4515 NAME: store_id_access storeurl_rewrite_access
4518 LOC: Config.accessList.store_id
4520 If defined, this access list specifies which requests are
4521 sent to the StoreID processes. By default all requests
4524 This clause supports both fast and slow acl types.
4525 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4528 NAME: store_id_bypass storeurl_rewrite_bypass
4530 LOC: Config.onoff.store_id_bypass
4533 When this is 'on', a request will not go through the
4534 helper if all helpers are busy. If this is 'off'
4535 and the helper queue grows too large, Squid will exit
4536 with a FATAL error and ask you to increase the number of
4537 helpers. You should only enable this if the helperss
4538 are not critical to your caching system. If you use
4539 helpers for critical caching components, and you enable this
4540 option, users may not get objects from cache.
4544 OPTIONS FOR TUNING THE CACHE
4545 -----------------------------------------------------------------------------
4548 NAME: cache no_cache
4551 LOC: Config.accessList.noCache
4553 A list of ACL elements which, if matched and denied, cause the request to
4554 not be satisfied from the cache and the reply to not be cached.
4555 In other words, use this to force certain objects to never be cached.
4557 You must use the words 'allow' or 'deny' to indicate whether items
4558 matching the ACL should be allowed or denied into the cache.
4560 Default is to allow all to be cached.
4562 This clause supports both fast and slow acl types.
4563 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4569 LOC: Config.maxStale
4572 This option puts an upper limit on how stale content Squid
4573 will serve from the cache if cache validation fails.
4574 Can be overriden by the refresh_pattern max-stale option.
4577 NAME: refresh_pattern
4578 TYPE: refreshpattern
4582 usage: refresh_pattern [-i] regex min percent max [options]
4584 By default, regular expressions are CASE-SENSITIVE. To make
4585 them case-insensitive, use the -i option.
4587 'Min' is the time (in minutes) an object without an explicit
4588 expiry time should be considered fresh. The recommended
4589 value is 0, any higher values may cause dynamic applications
4590 to be erroneously cached unless the application designer
4591 has taken the appropriate actions.
4593 'Percent' is a percentage of the objects age (time since last
4594 modification age) an object without explicit expiry time
4595 will be considered fresh.
4597 'Max' is an upper limit on how long objects without an explicit
4598 expiry time will be considered fresh.
4600 options: override-expire
4605 ignore-must-revalidate
4612 override-expire enforces min age even if the server
4613 sent an explicit expiry time (e.g., with the
4614 Expires: header or Cache-Control: max-age). Doing this
4615 VIOLATES the HTTP standard. Enabling this feature
4616 could make you liable for problems which it causes.
4618 Note: override-expire does not enforce staleness - it only extends
4619 freshness / min. If the server returns a Expires time which
4620 is longer than your max time, Squid will still consider
4621 the object fresh for that period of time.
4623 override-lastmod enforces min age even on objects
4624 that were modified recently.
4626 reload-into-ims changes client no-cache or ``reload''
4627 to If-Modified-Since requests. Doing this VIOLATES the
4628 HTTP standard. Enabling this feature could make you
4629 liable for problems which it causes.
4631 ignore-reload ignores a client no-cache or ``reload''
4632 header. Doing this VIOLATES the HTTP standard. Enabling
4633 this feature could make you liable for problems which
4636 ignore-no-store ignores any ``Cache-control: no-store''
4637 headers received from a server. Doing this VIOLATES
4638 the HTTP standard. Enabling this feature could make you
4639 liable for problems which it causes.
4641 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
4642 headers received from a server. Doing this VIOLATES
4643 the HTTP standard. Enabling this feature could make you
4644 liable for problems which it causes.
4646 ignore-private ignores any ``Cache-control: private''
4647 headers received from a server. Doing this VIOLATES
4648 the HTTP standard. Enabling this feature could make you
4649 liable for problems which it causes.
4651 ignore-auth caches responses to requests with authorization,
4652 as if the originserver had sent ``Cache-control: public''
4653 in the response header. Doing this VIOLATES the HTTP standard.
4654 Enabling this feature could make you liable for problems which
4657 refresh-ims causes squid to contact the origin server
4658 when a client issues an If-Modified-Since request. This
4659 ensures that the client will receive an updated version
4660 if one is available.
4662 store-stale stores responses even if they don't have explicit
4663 freshness or a validator (i.e., Last-Modified or an ETag)
4664 present, or if they're already stale. By default, Squid will
4665 not cache such responses because they usually can't be
4666 reused. Note that such responses will be stale by default.
4668 max-stale=NN provide a maximum staleness factor. Squid won't
4669 serve objects more stale than this even if it failed to
4670 validate the object. Default: use the max_stale global limit.
4672 Basically a cached object is:
4674 FRESH if expires < now, else STALE
4676 FRESH if lm-factor < percent, else STALE
4680 The refresh_pattern lines are checked in the order listed here.
4681 The first entry which matches is used. If none of the entries
4682 match the default will be used.
4684 Note, you must uncomment all the default lines if you want
4685 to change one. The default setting is only active if none is
4690 # Add any of your own refresh_pattern entries above these.
4691 refresh_pattern ^ftp: 1440 20% 10080
4692 refresh_pattern ^gopher: 1440 0% 1440
4693 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
4694 refresh_pattern . 0 20% 4320
4698 NAME: quick_abort_min
4702 LOC: Config.quickAbort.min
4705 NAME: quick_abort_max
4709 LOC: Config.quickAbort.max
4712 NAME: quick_abort_pct
4716 LOC: Config.quickAbort.pct
4718 The cache by default continues downloading aborted requests
4719 which are almost completed (less than 16 KB remaining). This
4720 may be undesirable on slow (e.g. SLIP) links and/or very busy
4721 caches. Impatient users may tie up file descriptors and
4722 bandwidth by repeatedly requesting and immediately aborting
4725 When the user aborts a request, Squid will check the
4726 quick_abort values to the amount of data transfered until
4729 If the transfer has less than 'quick_abort_min' KB remaining,
4730 it will finish the retrieval.
4732 If the transfer has more than 'quick_abort_max' KB remaining,
4733 it will abort the retrieval.
4735 If more than 'quick_abort_pct' of the transfer has completed,
4736 it will finish the retrieval.
4738 If you do not want any retrieval to continue after the client
4739 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
4742 If you want retrievals to always continue if they are being
4743 cached set 'quick_abort_min' to '-1 KB'.
4746 NAME: read_ahead_gap
4747 COMMENT: buffer-size
4749 LOC: Config.readAheadGap
4752 The amount of data the cache will buffer ahead of what has been
4753 sent to the client when retrieving an object from another server.
4757 IFDEF: USE_HTTP_VIOLATIONS
4760 LOC: Config.negativeTtl
4763 Set the Default Time-to-Live (TTL) for failed requests.
4764 Certain types of failures (such as "connection refused" and
4765 "404 Not Found") are able to be negatively-cached for a short time.
4766 Modern web servers should provide Expires: header, however if they
4767 do not this can provide a minimum TTL.
4768 The default is not to cache errors with unknown expiry details.
4770 Note that this is different from negative caching of DNS lookups.
4772 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4773 this feature could make you liable for problems which it
4777 NAME: positive_dns_ttl
4780 LOC: Config.positiveDnsTtl
4783 Upper limit on how long Squid will cache positive DNS responses.
4784 Default is 6 hours (360 minutes). This directive must be set
4785 larger than negative_dns_ttl.
4788 NAME: negative_dns_ttl
4791 LOC: Config.negativeDnsTtl
4794 Time-to-Live (TTL) for negative caching of failed DNS lookups.
4795 This also sets the lower cache limit on positive lookups.
4796 Minimum value is 1 second, and it is not recommendable to go
4797 much below 10 seconds.
4800 NAME: range_offset_limit
4801 COMMENT: size [acl acl...]
4803 LOC: Config.rangeOffsetLimit
4806 usage: (size) [units] [[!]aclname]
4808 Sets an upper limit on how far (number of bytes) into the file
4809 a Range request may be to cause Squid to prefetch the whole file.
4810 If beyond this limit, Squid forwards the Range request as it is and
4811 the result is NOT cached.
4813 This is to stop a far ahead range request (lets say start at 17MB)
4814 from making Squid fetch the whole object up to that point before
4815 sending anything to the client.
4817 Multiple range_offset_limit lines may be specified, and they will
4818 be searched from top to bottom on each request until a match is found.
4819 The first match found will be used. If no line matches a request, the
4820 default limit of 0 bytes will be used.
4822 'size' is the limit specified as a number of units.
4824 'units' specifies whether to use bytes, KB, MB, etc.
4825 If no units are specified bytes are assumed.
4827 A size of 0 causes Squid to never fetch more than the
4828 client requested. (default)
4830 A size of 'none' causes Squid to always fetch the object from the
4831 beginning so it may cache the result. (2.0 style)
4833 'aclname' is the name of a defined ACL.
4835 NP: Using 'none' as the byte value here will override any quick_abort settings
4836 that may otherwise apply to the range request. The range request will
4837 be fully fetched from start to finish regardless of the client
4838 actions. This affects bandwidth usage.
4841 NAME: minimum_expiry_time
4844 LOC: Config.minimum_expiry_time
4847 The minimum caching time according to (Expires - Date)
4848 Headers Squid honors if the object can't be revalidated
4849 defaults to 60 seconds. In reverse proxy environments it
4850 might be desirable to honor shorter object lifetimes. It
4851 is most likely better to make your server return a
4852 meaningful Last-Modified header however. In ESI environments
4853 where page fragments often have short lifetimes, this will
4854 often be best set to 0.
4857 NAME: store_avg_object_size
4861 LOC: Config.Store.avgObjectSize
4863 Average object size, used to estimate number of objects your
4864 cache can hold. The default is 13 KB.
4867 NAME: store_objects_per_bucket
4870 LOC: Config.Store.objectsPerBucket
4872 Target number of objects per bucket in the store hash table.
4873 Lowering this value increases the total number of buckets and
4874 also the storage maintenance rate. The default is 20.
4879 -----------------------------------------------------------------------------
4882 NAME: request_header_max_size
4886 LOC: Config.maxRequestHeaderSize
4888 This specifies the maximum size for HTTP headers in a request.
4889 Request headers are usually relatively small (about 512 bytes).
4890 Placing a limit on the request header size will catch certain
4891 bugs (for example with persistent connections) and possibly
4892 buffer-overflow or denial-of-service attacks.
4895 NAME: reply_header_max_size
4899 LOC: Config.maxReplyHeaderSize
4901 This specifies the maximum size for HTTP headers in a reply.
4902 Reply headers are usually relatively small (about 512 bytes).
4903 Placing a limit on the reply header size will catch certain
4904 bugs (for example with persistent connections) and possibly
4905 buffer-overflow or denial-of-service attacks.
4908 NAME: request_body_max_size
4912 LOC: Config.maxRequestBodySize
4914 This specifies the maximum size for an HTTP request body.
4915 In other words, the maximum size of a PUT/POST request.
4916 A user who attempts to send a request with a body larger
4917 than this limit receives an "Invalid Request" error message.
4918 If you set this parameter to a zero (the default), there will
4919 be no limit imposed.
4922 NAME: client_request_buffer_max_size
4926 LOC: Config.maxRequestBufferSize
4928 This specifies the maximum buffer size of a client request.
4929 It prevents squid eating too much memory when somebody uploads
4933 NAME: chunked_request_body_max_size
4937 LOC: Config.maxChunkedRequestBodySize
4939 A broken or confused HTTP/1.1 client may send a chunked HTTP
4940 request to Squid. Squid does not have full support for that
4941 feature yet. To cope with such requests, Squid buffers the
4942 entire request and then dechunks request body to create a
4943 plain HTTP/1.0 request with a known content length. The plain
4944 request is then used by the rest of Squid code as usual.
4946 The option value specifies the maximum size of the buffer used
4947 to hold the request before the conversion. If the chunked
4948 request size exceeds the specified limit, the conversion
4949 fails, and the client receives an "unsupported request" error,
4950 as if dechunking was disabled.
4952 Dechunking is enabled by default. To disable conversion of
4953 chunked requests, set the maximum to zero.
4955 Request dechunking feature and this option in particular are a
4956 temporary hack. When chunking requests and responses are fully
4957 supported, there will be no need to buffer a chunked request.
4961 IFDEF: USE_HTTP_VIOLATIONS
4964 LOC: Config.accessList.brokenPosts
4966 A list of ACL elements which, if matched, causes Squid to send
4967 an extra CRLF pair after the body of a PUT/POST request.
4969 Some HTTP servers has broken implementations of PUT/POST,
4970 and rely on an extra CRLF pair sent by some WWW clients.
4972 Quote from RFC2616 section 4.1 on this matter:
4974 Note: certain buggy HTTP/1.0 client implementations generate an
4975 extra CRLF's after a POST request. To restate what is explicitly
4976 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
4977 a request with an extra CRLF.
4979 This clause only supports fast acl types.
4980 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4983 acl buggy_server url_regex ^http://....
4984 broken_posts allow buggy_server
4987 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
4990 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
4992 LOC: Adaptation::Config::use_indirect_client
4994 Controls whether the indirect client IP address (instead of the direct
4995 client IP address) is passed to adaptation services.
4997 See also: follow_x_forwarded_for adaptation_send_client_ip
5001 IFDEF: USE_HTTP_VIOLATIONS
5005 LOC: Config.onoff.via
5007 If set (default), Squid will include a Via header in requests and
5008 replies as required by RFC2616.
5014 LOC: Config.onoff.ie_refresh
5017 Microsoft Internet Explorer up until version 5.5 Service
5018 Pack 1 has an issue with transparent proxies, wherein it
5019 is impossible to force a refresh. Turning this on provides
5020 a partial fix to the problem, by causing all IMS-REFRESH
5021 requests from older IE versions to check the origin server
5022 for fresh content. This reduces hit ratio by some amount
5023 (~10% in my experience), but allows users to actually get
5024 fresh content when they want it. Note because Squid
5025 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5026 of 5.5 is unchanged from old versions of Squid (i.e. a
5027 forced refresh is impossible). Newer versions of IE will,
5028 hopefully, continue to have the new behavior and will be
5029 handled based on that assumption. This option defaults to
5030 the old Squid behavior, which is better for hit ratios but
5031 worse for clients using IE, if they need to be able to
5032 force fresh content.
5035 NAME: vary_ignore_expire
5038 LOC: Config.onoff.vary_ignore_expire
5041 Many HTTP servers supporting Vary gives such objects
5042 immediate expiry time with no cache-control header
5043 when requested by a HTTP/1.0 client. This option
5044 enables Squid to ignore such expiry times until
5045 HTTP/1.1 is fully implemented.
5047 WARNING: If turned on this may eventually cause some
5048 varying objects not intended for caching to get cached.
5051 NAME: request_entities
5053 LOC: Config.onoff.request_entities
5056 Squid defaults to deny GET and HEAD requests with request entities,
5057 as the meaning of such requests are undefined in the HTTP standard
5058 even if not explicitly forbidden.
5060 Set this directive to on if you have clients which insists
5061 on sending request entities in GET or HEAD requests. But be warned
5062 that there is server software (both proxies and web servers) which
5063 can fail to properly process this kind of request which may make you
5064 vulnerable to cache pollution attacks if enabled.
5067 NAME: request_header_access
5068 IFDEF: USE_HTTP_VIOLATIONS
5069 TYPE: http_header_access
5070 LOC: Config.request_header_access
5073 Usage: request_header_access header_name allow|deny [!]aclname ...
5075 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5076 this feature could make you liable for problems which it
5079 This option replaces the old 'anonymize_headers' and the
5080 older 'http_anonymizer' option with something that is much
5081 more configurable. A list of ACLs for each header name allows
5082 removal of specific header fields under specific conditions.
5084 This option only applies to outgoing HTTP request headers (i.e.,
5085 headers sent by Squid to the next HTTP hop such as a cache peer
5086 or an origin server). The option has no effect during cache hit
5087 detection. The equivalent adaptation vectoring point in ICAP
5088 terminology is post-cache REQMOD.
5090 The option is applied to individual outgoing request header
5091 fields. For each request header field F, Squid uses the first
5092 qualifying sets of request_header_access rules:
5094 1. Rules with header_name equal to F's name.
5095 2. Rules with header_name 'Other', provided F's name is not
5096 on the hard-coded list of commonly used HTTP header names.
5097 3. Rules with header_name 'All'.
5099 Within that qualifying rule set, rule ACLs are checked as usual.
5100 If ACLs of an "allow" rule match, the header field is allowed to
5101 go through as is. If ACLs of a "deny" rule match, the header is
5102 removed and request_header_replace is then checked to identify
5103 if the removed header has a replacement. If no rules within the
5104 set have matching ACLs, the header field is left as is.
5106 For example, to achieve the same behavior as the old
5107 'http_anonymizer standard' option, you should use:
5109 request_header_access From deny all
5110 request_header_access Referer deny all
5111 request_header_access Server deny all
5112 request_header_access User-Agent deny all
5113 request_header_access WWW-Authenticate deny all
5114 request_header_access Link deny all
5116 Or, to reproduce the old 'http_anonymizer paranoid' feature
5119 request_header_access Allow allow all
5120 request_header_access Authorization allow all
5121 request_header_access WWW-Authenticate allow all
5122 request_header_access Proxy-Authorization allow all
5123 request_header_access Proxy-Authenticate allow all
5124 request_header_access Cache-Control allow all
5125 request_header_access Content-Encoding allow all
5126 request_header_access Content-Length allow all
5127 request_header_access Content-Type allow all
5128 request_header_access Date allow all
5129 request_header_access Expires allow all
5130 request_header_access Host allow all
5131 request_header_access If-Modified-Since allow all
5132 request_header_access Last-Modified allow all
5133 request_header_access Location allow all
5134 request_header_access Pragma allow all
5135 request_header_access Accept allow all
5136 request_header_access Accept-Charset allow all
5137 request_header_access Accept-Encoding allow all
5138 request_header_access Accept-Language allow all
5139 request_header_access Content-Language allow all
5140 request_header_access Mime-Version allow all
5141 request_header_access Retry-After allow all
5142 request_header_access Title allow all
5143 request_header_access Connection allow all
5144 request_header_access All deny all
5146 although many of those are HTTP reply headers, and so should be
5147 controlled with the reply_header_access directive.
5149 By default, all headers are allowed (no anonymizing is
5153 NAME: reply_header_access
5154 IFDEF: USE_HTTP_VIOLATIONS
5155 TYPE: http_header_access
5156 LOC: Config.reply_header_access
5159 Usage: reply_header_access header_name allow|deny [!]aclname ...
5161 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5162 this feature could make you liable for problems which it
5165 This option only applies to reply headers, i.e., from the
5166 server to the client.
5168 This is the same as request_header_access, but in the other
5169 direction. Please see request_header_access for detailed
5172 For example, to achieve the same behavior as the old
5173 'http_anonymizer standard' option, you should use:
5175 reply_header_access From deny all
5176 reply_header_access Referer deny all
5177 reply_header_access Server deny all
5178 reply_header_access User-Agent deny all
5179 reply_header_access WWW-Authenticate deny all
5180 reply_header_access Link deny all
5182 Or, to reproduce the old 'http_anonymizer paranoid' feature
5185 reply_header_access Allow allow all
5186 reply_header_access Authorization allow all
5187 reply_header_access WWW-Authenticate allow all
5188 reply_header_access Proxy-Authorization allow all
5189 reply_header_access Proxy-Authenticate allow all
5190 reply_header_access Cache-Control allow all
5191 reply_header_access Content-Encoding allow all
5192 reply_header_access Content-Length allow all
5193 reply_header_access Content-Type allow all
5194 reply_header_access Date allow all
5195 reply_header_access Expires allow all
5196 reply_header_access Host allow all
5197 reply_header_access If-Modified-Since allow all
5198 reply_header_access Last-Modified allow all
5199 reply_header_access Location allow all
5200 reply_header_access Pragma allow all
5201 reply_header_access Accept allow all
5202 reply_header_access Accept-Charset allow all
5203 reply_header_access Accept-Encoding allow all
5204 reply_header_access Accept-Language allow all
5205 reply_header_access Content-Language allow all
5206 reply_header_access Mime-Version allow all
5207 reply_header_access Retry-After allow all
5208 reply_header_access Title allow all
5209 reply_header_access Connection allow all
5210 reply_header_access All deny all
5212 although the HTTP request headers won't be usefully controlled
5213 by this directive -- see request_header_access for details.
5215 By default, all headers are allowed (no anonymizing is
5219 NAME: request_header_replace header_replace
5220 IFDEF: USE_HTTP_VIOLATIONS
5221 TYPE: http_header_replace
5222 LOC: Config.request_header_access
5225 Usage: request_header_replace header_name message
5226 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
5228 This option allows you to change the contents of headers
5229 denied with request_header_access above, by replacing them
5230 with some fixed string. This replaces the old fake_user_agent
5233 This only applies to request headers, not reply headers.
5235 By default, headers are removed if denied.
5238 NAME: reply_header_replace
5239 IFDEF: USE_HTTP_VIOLATIONS
5240 TYPE: http_header_replace
5241 LOC: Config.reply_header_access
5244 Usage: reply_header_replace header_name message
5245 Example: reply_header_replace Server Foo/1.0
5247 This option allows you to change the contents of headers
5248 denied with reply_header_access above, by replacing them
5249 with some fixed string.
5251 This only applies to reply headers, not request headers.
5253 By default, headers are removed if denied.
5256 NAME: request_header_add
5257 TYPE: HeaderWithAclList
5258 LOC: Config.request_header_add
5261 Usage: request_header_add field-name field-value acl1 [acl2] ...
5262 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
5264 This option adds header fields to outgoing HTTP requests (i.e.,
5265 request headers sent by Squid to the next HTTP hop such as a
5266 cache peer or an origin server). The option has no effect during
5267 cache hit detection. The equivalent adaptation vectoring point
5268 in ICAP terminology is post-cache REQMOD.
5270 Field-name is a token specifying an HTTP header name. If a
5271 standard HTTP header name is used, Squid does not check whether
5272 the new header conflicts with any existing headers or violates
5273 HTTP rules. If the request to be modified already contains a
5274 field with the same name, the old field is preserved but the
5275 header field values are not merged.
5277 Field-value is either a token or a quoted string. If quoted
5278 string format is used, then the surrounding quotes are removed
5279 while escape sequences and %macros are processed.
5281 In theory, all of the logformat codes can be used as %macros.
5282 However, unlike logging (which happens at the very end of
5283 transaction lifetime), the transaction may not yet have enough
5284 information to expand a macro when the new header value is needed.
5285 And some information may already be available to Squid but not yet
5286 committed where the macro expansion code can access it (report
5287 such instances!). The macro will be expanded into a single dash
5288 ('-') in such cases. Not all macros have been tested.
5290 One or more Squid ACLs may be specified to restrict header
5291 injection to matching requests. As always in squid.conf, all
5292 ACLs in an option ACL list must be satisfied for the insertion
5293 to happen. The request_header_add option supports fast ACLs
5302 This option used to log custom information about the master
5303 transaction. For example, an admin may configure Squid to log
5304 which "user group" the transaction belongs to, where "user group"
5305 will be determined based on a set of ACLs and not [just]
5306 authentication information.
5307 Values of key/value pairs can be logged using %{key}note macros:
5309 note key value acl ...
5310 logformat myFormat ... %{key}note ...
5313 NAME: relaxed_header_parser
5314 COMMENT: on|off|warn
5316 LOC: Config.onoff.relaxed_header_parser
5319 In the default "on" setting Squid accepts certain forms
5320 of non-compliant HTTP messages where it is unambiguous
5321 what the sending application intended even if the message
5322 is not correctly formatted. The messages is then normalized
5323 to the correct form when forwarded by Squid.
5325 If set to "warn" then a warning will be emitted in cache.log
5326 each time such HTTP error is encountered.
5328 If set to "off" then such HTTP errors will cause the request
5329 or response to be rejected.
5334 -----------------------------------------------------------------------------
5337 NAME: forward_timeout
5340 LOC: Config.Timeout.forward
5343 This parameter specifies how long Squid should at most attempt in
5344 finding a forwarding path for the request before giving up.
5347 NAME: connect_timeout
5350 LOC: Config.Timeout.connect
5353 This parameter specifies how long to wait for the TCP connect to
5354 the requested server or peer to complete before Squid should
5355 attempt to find another path where to forward the request.
5358 NAME: peer_connect_timeout
5361 LOC: Config.Timeout.peer_connect
5364 This parameter specifies how long to wait for a pending TCP
5365 connection to a peer cache. The default is 30 seconds. You
5366 may also set different timeout values for individual neighbors
5367 with the 'connect-timeout' option on a 'cache_peer' line.
5373 LOC: Config.Timeout.read
5376 The read_timeout is applied on server-side connections. After
5377 each successful read(), the timeout will be extended by this
5378 amount. If no data is read again after this amount of time,
5379 the request is aborted and logged with ERR_READ_TIMEOUT. The
5380 default is 15 minutes.
5386 LOC: Config.Timeout.write
5389 This timeout is tracked for all connections that have data
5390 available for writing and are waiting for the socket to become
5391 ready. After each successful write, the timeout is extended by
5392 the configured amount. If Squid has data to write but the
5393 connection is not ready for the configured duration, the
5394 transaction associated with the connection is terminated. The
5395 default is 15 minutes.
5398 NAME: request_timeout
5400 LOC: Config.Timeout.request
5403 How long to wait for complete HTTP request headers after initial
5404 connection establishment.
5407 NAME: client_idle_pconn_timeout persistent_request_timeout
5409 LOC: Config.Timeout.clientIdlePconn
5412 How long to wait for the next HTTP request on a persistent
5413 client connection after the previous request completes.
5416 NAME: client_lifetime
5419 LOC: Config.Timeout.lifetime
5422 The maximum amount of time a client (browser) is allowed to
5423 remain connected to the cache process. This protects the Cache
5424 from having a lot of sockets (and hence file descriptors) tied up
5425 in a CLOSE_WAIT state from remote clients that go away without
5426 properly shutting down (either because of a network failure or
5427 because of a poor client implementation). The default is one
5430 NOTE: The default value is intended to be much larger than any
5431 client would ever need to be connected to your cache. You
5432 should probably change client_lifetime only as a last resort.
5433 If you seem to have many client connections tying up
5434 filedescriptors, we recommend first tuning the read_timeout,
5435 request_timeout, persistent_request_timeout and quick_abort values.
5438 NAME: half_closed_clients
5440 LOC: Config.onoff.half_closed_clients
5443 Some clients may shutdown the sending side of their TCP
5444 connections, while leaving their receiving sides open. Sometimes,
5445 Squid can not tell the difference between a half-closed and a
5446 fully-closed TCP connection.
5448 By default, Squid will immediately close client connections when
5449 read(2) returns "no more data to read."
5451 Change this option to 'on' and Squid will keep open connections
5452 until a read(2) or write(2) on the socket returns an error.
5453 This may show some benefits for reverse proxies. But if not
5454 it is recommended to leave OFF.
5457 NAME: server_idle_pconn_timeout pconn_timeout
5459 LOC: Config.Timeout.serverIdlePconn
5462 Timeout for idle persistent connections to servers and other
5469 LOC: Ident::TheConfig.timeout
5472 Maximum time to wait for IDENT lookups to complete.
5474 If this is too high, and you enabled IDENT lookups from untrusted
5475 users, you might be susceptible to denial-of-service by having
5476 many ident requests going at once.
5479 NAME: shutdown_lifetime
5482 LOC: Config.shutdownLifetime
5485 When SIGTERM or SIGHUP is received, the cache is put into
5486 "shutdown pending" mode until all active sockets are closed.
5487 This value is the lifetime to set for all open descriptors
5488 during shutdown mode. Any active clients after this many
5489 seconds will receive a 'timeout' message.
5493 ADMINISTRATIVE PARAMETERS
5494 -----------------------------------------------------------------------------
5500 LOC: Config.adminEmail
5502 Email-address of local cache manager who will receive
5503 mail if the cache dies. The default is "webmaster."
5509 LOC: Config.EmailFrom
5511 From: email-address for mail sent when the cache dies.
5512 The default is to use 'appname@unique_hostname'.
5513 Default appname value is "squid", can be changed into
5514 src/globals.h before building squid.
5520 LOC: Config.EmailProgram
5522 Email program used to send mail if the cache dies.
5523 The default is "mail". The specified program must comply
5524 with the standard Unix mail syntax:
5525 mail-program recipient < mailfile
5527 Optional command line options can be specified.
5530 NAME: cache_effective_user
5532 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
5533 LOC: Config.effectiveUser
5535 If you start Squid as root, it will change its effective/real
5536 UID/GID to the user specified below. The default is to change
5537 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
5538 see also; cache_effective_group
5541 NAME: cache_effective_group
5544 LOC: Config.effectiveGroup
5546 Squid sets the GID to the effective user's default group ID
5547 (taken from the password file) and supplementary group list
5548 from the groups membership.
5550 If you want Squid to run with a specific GID regardless of
5551 the group memberships of the effective user then set this
5552 to the group (or GID) you want Squid to run as. When set
5553 all other group privileges of the effective user are ignored
5554 and only this GID is effective. If Squid is not started as
5555 root the user starting Squid MUST be member of the specified
5558 This option is not recommended by the Squid Team.
5559 Our preference is for administrators to configure a secure
5560 user account for squid with UID/GID matching system policies.
5563 NAME: httpd_suppress_version_string
5567 LOC: Config.onoff.httpd_suppress_version_string
5569 Suppress Squid version string info in HTTP headers and HTML error pages.
5572 NAME: visible_hostname
5574 LOC: Config.visibleHostname
5577 If you want to present a special hostname in error messages, etc,
5578 define this. Otherwise, the return value of gethostname()
5579 will be used. If you have multiple caches in a cluster and
5580 get errors about IP-forwarding you must set them to have individual
5581 names with this setting.
5584 NAME: unique_hostname
5586 LOC: Config.uniqueHostname
5589 If you want to have multiple machines with the same
5590 'visible_hostname' you must give each machine a different
5591 'unique_hostname' so forwarding loops can be detected.
5594 NAME: hostname_aliases
5596 LOC: Config.hostnameAliases
5599 A list of other DNS names your cache has.
5607 Minimum umask which should be enforced while the proxy
5608 is running, in addition to the umask set at startup.
5610 For a traditional octal representation of umasks, start
5615 OPTIONS FOR THE CACHE REGISTRATION SERVICE
5616 -----------------------------------------------------------------------------
5618 This section contains parameters for the (optional) cache
5619 announcement service. This service is provided to help
5620 cache administrators locate one another in order to join or
5621 create cache hierarchies.
5623 An 'announcement' message is sent (via UDP) to the registration
5624 service by Squid. By default, the announcement message is NOT
5625 SENT unless you enable it with 'announce_period' below.
5627 The announcement message includes your hostname, plus the
5628 following information from this configuration file:
5634 All current information is processed regularly and made
5635 available on the Web at http://www.ircache.net/Cache/Tracker/.
5638 NAME: announce_period
5640 LOC: Config.Announce.period
5643 This is how frequently to send cache announcements. The
5644 default is `0' which disables sending the announcement
5647 To enable announcing your cache, just set an announce period.
5650 announce_period 1 day
5655 DEFAULT: tracker.ircache.net
5656 LOC: Config.Announce.host
5662 LOC: Config.Announce.file
5668 LOC: Config.Announce.port
5670 announce_host and announce_port set the hostname and port
5671 number where the registration message will be sent.
5673 Hostname will default to 'tracker.ircache.net' and port will
5674 default default to 3131. If the 'filename' argument is given,
5675 the contents of that file will be included in the announce
5680 HTTPD-ACCELERATOR OPTIONS
5681 -----------------------------------------------------------------------------
5684 NAME: httpd_accel_surrogate_id
5687 LOC: Config.Accel.surrogate_id
5689 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
5690 need an identification token to allow control targeting. Because
5691 a farm of surrogates may all perform the same tasks, they may share
5692 an identification token.
5694 The default ID is the visible_hostname
5697 NAME: http_accel_surrogate_remote
5701 LOC: Config.onoff.surrogate_is_remote
5703 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
5704 Set this to on to have squid behave as a remote surrogate.
5708 IFDEF: USE_SQUID_ESI
5709 COMMENT: libxml2|expat|custom
5711 LOC: ESIParser::Type
5714 ESI markup is not strictly XML compatible. The custom ESI parser
5715 will give higher performance, but cannot handle non ASCII character
5720 DELAY POOL PARAMETERS
5721 -----------------------------------------------------------------------------
5725 TYPE: delay_pool_count
5727 IFDEF: USE_DELAY_POOLS
5730 This represents the number of delay pools to be used. For example,
5731 if you have one class 2 delay pool and one class 3 delays pool, you
5732 have a total of 2 delay pools.
5736 TYPE: delay_pool_class
5738 IFDEF: USE_DELAY_POOLS
5741 This defines the class of each delay pool. There must be exactly one
5742 delay_class line for each delay pool. For example, to define two
5743 delay pools, one of class 2 and one of class 3, the settings above
5747 delay_pools 4 # 4 delay pools
5748 delay_class 1 2 # pool 1 is a class 2 pool
5749 delay_class 2 3 # pool 2 is a class 3 pool
5750 delay_class 3 4 # pool 3 is a class 4 pool
5751 delay_class 4 5 # pool 4 is a class 5 pool
5753 The delay pool classes are:
5755 class 1 Everything is limited by a single aggregate
5758 class 2 Everything is limited by a single aggregate
5759 bucket as well as an "individual" bucket chosen
5760 from bits 25 through 32 of the IPv4 address.
5762 class 3 Everything is limited by a single aggregate
5763 bucket as well as a "network" bucket chosen
5764 from bits 17 through 24 of the IP address and a
5765 "individual" bucket chosen from bits 17 through
5766 32 of the IPv4 address.
5768 class 4 Everything in a class 3 delay pool, with an
5769 additional limit on a per user basis. This
5770 only takes effect if the username is established
5771 in advance - by forcing authentication in your
5774 class 5 Requests are grouped according their tag (see
5775 external_acl's tag= reply).
5778 Each pool also requires a delay_parameters directive to configure the pool size
5779 and speed limits used whenever the pool is applied to a request. Along with
5780 a set of delay_access directives to determine when it is used.
5782 NOTE: If an IP address is a.b.c.d
5783 -> bits 25 through 32 are "d"
5784 -> bits 17 through 24 are "c"
5785 -> bits 17 through 32 are "c * 256 + d"
5787 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
5788 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
5792 TYPE: delay_pool_access
5794 IFDEF: USE_DELAY_POOLS
5797 This is used to determine which delay pool a request falls into.
5799 delay_access is sorted per pool and the matching starts with pool 1,
5800 then pool 2, ..., and finally pool N. The first delay pool where the
5801 request is allowed is selected for the request. If it does not allow
5802 the request to any pool then the request is not delayed (default).
5804 For example, if you want some_big_clients in delay
5805 pool 1 and lotsa_little_clients in delay pool 2:
5808 delay_access 1 allow some_big_clients
5809 delay_access 1 deny all
5810 delay_access 2 allow lotsa_little_clients
5811 delay_access 2 deny all
5812 delay_access 3 allow authenticated_clients
5815 NAME: delay_parameters
5816 TYPE: delay_pool_rates
5818 IFDEF: USE_DELAY_POOLS
5821 This defines the parameters for a delay pool. Each delay pool has
5822 a number of "buckets" associated with it, as explained in the
5823 description of delay_class.
5825 For a class 1 delay pool, the syntax is:
5827 delay_parameters pool aggregate
5829 For a class 2 delay pool:
5831 delay_parameters pool aggregate individual
5833 For a class 3 delay pool:
5835 delay_parameters pool aggregate network individual
5837 For a class 4 delay pool:
5839 delay_parameters pool aggregate network individual user
5841 For a class 5 delay pool:
5843 delay_parameters pool tagrate
5845 The option variables are:
5847 pool a pool number - ie, a number between 1 and the
5848 number specified in delay_pools as used in
5851 aggregate the speed limit parameters for the aggregate bucket
5854 individual the speed limit parameters for the individual
5855 buckets (class 2, 3).
5857 network the speed limit parameters for the network buckets
5860 user the speed limit parameters for the user buckets
5863 tagrate the speed limit parameters for the tag buckets
5866 A pair of delay parameters is written restore/maximum, where restore is
5867 the number of bytes (not bits - modem and network speeds are usually
5868 quoted in bits) per second placed into the bucket, and maximum is the
5869 maximum number of bytes which can be in the bucket at any time.
5871 There must be one delay_parameters line for each delay pool.
5874 For example, if delay pool number 1 is a class 2 delay pool as in the
5875 above example, and is being used to strictly limit each host to 64Kbit/sec
5876 (plus overheads), with no overall limit, the line is:
5878 delay_parameters 1 -1/-1 8000/8000
5880 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
5882 Note that the figure -1 is used to represent "unlimited".
5885 And, if delay pool number 2 is a class 3 delay pool as in the above
5886 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
5887 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
5888 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
5889 to permit a decent web page to be downloaded at a decent speed
5890 (if the network is not being limited due to overuse) but slow down
5891 large downloads more significantly:
5893 delay_parameters 2 32000/32000 8000/8000 600/8000
5895 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
5896 8 x 8000 KByte/sec -> 64Kbit/sec.
5897 8 x 600 Byte/sec -> 4800bit/sec.
5900 Finally, for a class 4 delay pool as in the example - each user will
5901 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
5903 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
5906 NAME: delay_initial_bucket_level
5907 COMMENT: (percent, 0-100)
5910 IFDEF: USE_DELAY_POOLS
5911 LOC: Config.Delay.initial
5913 The initial bucket percentage is used to determine how much is put
5914 in each bucket when squid starts, is reconfigured, or first notices
5915 a host accessing it (in class 2 and class 3, individual hosts and
5916 networks only have buckets associated with them once they have been
5921 CLIENT DELAY POOL PARAMETERS
5922 -----------------------------------------------------------------------------
5925 NAME: client_delay_pools
5926 TYPE: client_delay_pool_count
5928 IFDEF: USE_DELAY_POOLS
5929 LOC: Config.ClientDelay
5931 This option specifies the number of client delay pools used. It must
5932 preceed other client_delay_* options.
5935 client_delay_pools 2
5938 NAME: client_delay_initial_bucket_level
5939 COMMENT: (percent, 0-no_limit)
5942 IFDEF: USE_DELAY_POOLS
5943 LOC: Config.ClientDelay.initial
5945 This option determines the initial bucket size as a percentage of
5946 max_bucket_size from client_delay_parameters. Buckets are created
5947 at the time of the "first" connection from the matching IP. Idle
5948 buckets are periodically deleted up.
5950 You can specify more than 100 percent but note that such "oversized"
5951 buckets are not refilled until their size goes down to max_bucket_size
5952 from client_delay_parameters.
5955 client_delay_initial_bucket_level 50
5958 NAME: client_delay_parameters
5959 TYPE: client_delay_pool_rates
5961 IFDEF: USE_DELAY_POOLS
5962 LOC: Config.ClientDelay
5965 This option configures client-side bandwidth limits using the
5968 client_delay_parameters pool speed_limit max_bucket_size
5970 pool is an integer ID used for client_delay_access matching.
5972 speed_limit is bytes added to the bucket per second.
5974 max_bucket_size is the maximum size of a bucket, enforced after any
5975 speed_limit additions.
5977 Please see the delay_parameters option for more information and
5981 client_delay_parameters 1 1024 2048
5982 client_delay_parameters 2 51200 16384
5985 NAME: client_delay_access
5986 TYPE: client_delay_pool_access
5988 IFDEF: USE_DELAY_POOLS
5989 LOC: Config.ClientDelay
5992 This option determines the client-side delay pool for the
5995 client_delay_access pool_ID allow|deny acl_name
5997 All client_delay_access options are checked in their pool ID
5998 order, starting with pool 1. The first checked pool with allowed
5999 request is selected for the request. If no ACL matches or there
6000 are no client_delay_access options, the request bandwidth is not
6003 The ACL-selected pool is then used to find the
6004 client_delay_parameters for the request. Client-side pools are
6005 not used to aggregate clients. Clients are always aggregated
6006 based on their source IP addresses (one bucket per source IP).
6008 Please see delay_access for more examples.
6011 client_delay_access 1 allow low_rate_network
6012 client_delay_access 2 allow vips_network
6016 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6017 -----------------------------------------------------------------------------
6022 LOC: Config.Wccp.router
6026 Use this option to define your WCCP ``home'' router for
6029 wccp_router supports a single WCCP(v1) router
6031 wccp2_router supports multiple WCCPv2 routers
6033 only one of the two may be used at the same time and defines
6034 which version of WCCP to use.
6038 TYPE: IpAddress_list
6039 LOC: Config.Wccp2.router
6043 Use this option to define your WCCP ``home'' router for
6046 wccp_router supports a single WCCP(v1) router
6048 wccp2_router supports multiple WCCPv2 routers
6050 only one of the two may be used at the same time and defines
6051 which version of WCCP to use.
6056 LOC: Config.Wccp.version
6060 This directive is only relevant if you need to set up WCCP(v1)
6061 to some very old and end-of-life Cisco routers. In all other
6062 setups it must be left unset or at the default setting.
6063 It defines an internal version in the WCCP(v1) protocol,
6064 with version 4 being the officially documented protocol.
6066 According to some users, Cisco IOS 11.2 and earlier only
6067 support WCCP version 3. If you're using that or an earlier
6068 version of IOS, you may need to change this value to 3, otherwise
6069 do not specify this parameter.
6072 NAME: wccp2_rebuild_wait
6074 LOC: Config.Wccp2.rebuildwait
6078 If this is enabled Squid will wait for the cache dir rebuild to finish
6079 before sending the first wccp2 HereIAm packet
6082 NAME: wccp2_forwarding_method
6084 LOC: Config.Wccp2.forwarding_method
6088 WCCP2 allows the setting of forwarding methods between the
6089 router/switch and the cache. Valid values are as follows:
6091 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6092 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6094 Currently (as of IOS 12.4) cisco routers only support GRE.
6095 Cisco switches only support the L2 redirect assignment method.
6098 NAME: wccp2_return_method
6100 LOC: Config.Wccp2.return_method
6104 WCCP2 allows the setting of return methods between the
6105 router/switch and the cache for packets that the cache
6106 decides not to handle. Valid values are as follows:
6108 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6109 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6111 Currently (as of IOS 12.4) cisco routers only support GRE.
6112 Cisco switches only support the L2 redirect assignment.
6114 If the "ip wccp redirect exclude in" command has been
6115 enabled on the cache interface, then it is still safe for
6116 the proxy server to use a l2 redirect method even if this
6117 option is set to GRE.
6120 NAME: wccp2_assignment_method
6122 LOC: Config.Wccp2.assignment_method
6126 WCCP2 allows the setting of methods to assign the WCCP hash
6127 Valid values are as follows:
6129 hash - Hash assignment
6130 mask - Mask assignment
6132 As a general rule, cisco routers support the hash assignment method
6133 and cisco switches support the mask assignment method.
6138 LOC: Config.Wccp2.info
6139 DEFAULT_IF_NONE: standard 0
6142 WCCP2 allows for multiple traffic services. There are two
6143 types: "standard" and "dynamic". The standard type defines
6144 one service id - http (id 0). The dynamic service ids can be from
6145 51 to 255 inclusive. In order to use a dynamic service id
6146 one must define the type of traffic to be redirected; this is done
6147 using the wccp2_service_info option.
6149 The "standard" type does not require a wccp2_service_info option,
6150 just specifying the service id will suffice.
6152 MD5 service authentication can be enabled by adding
6153 "password=<password>" to the end of this service declaration.
6157 wccp2_service standard 0 # for the 'web-cache' standard service
6158 wccp2_service dynamic 80 # a dynamic service type which will be
6159 # fleshed out with subsequent options.
6160 wccp2_service standard 0 password=foo
6163 NAME: wccp2_service_info
6164 TYPE: wccp2_service_info
6165 LOC: Config.Wccp2.info
6169 Dynamic WCCPv2 services require further information to define the
6170 traffic you wish to have diverted.
6174 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
6175 priority=<priority> ports=<port>,<port>..
6177 The relevant WCCPv2 flags:
6178 + src_ip_hash, dst_ip_hash
6179 + source_port_hash, dst_port_hash
6180 + src_ip_alt_hash, dst_ip_alt_hash
6181 + src_port_alt_hash, dst_port_alt_hash
6184 The port list can be one to eight entries.
6188 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
6189 priority=240 ports=80
6191 Note: the service id must have been defined by a previous
6192 'wccp2_service dynamic <id>' entry.
6197 LOC: Config.Wccp2.weight
6201 Each cache server gets assigned a set of the destination
6202 hash proportional to their weight.
6207 LOC: Config.Wccp.address
6214 LOC: Config.Wccp2.address
6218 Use this option if you require WCCP to use a specific
6221 The default behavior is to not bind to any specific address.
6225 PERSISTENT CONNECTION HANDLING
6226 -----------------------------------------------------------------------------
6228 Also see "pconn_timeout" in the TIMEOUTS section
6231 NAME: client_persistent_connections
6233 LOC: Config.onoff.client_pconns
6237 NAME: server_persistent_connections
6239 LOC: Config.onoff.server_pconns
6242 Persistent connection support for clients and servers. By
6243 default, Squid uses persistent connections (when allowed)
6244 with its clients and servers. You can use these options to
6245 disable persistent connections with clients and/or servers.
6248 NAME: persistent_connection_after_error
6250 LOC: Config.onoff.error_pconns
6253 With this directive the use of persistent connections after
6254 HTTP errors can be disabled. Useful if you have clients
6255 who fail to handle errors on persistent connections proper.
6258 NAME: detect_broken_pconn
6260 LOC: Config.onoff.detect_broken_server_pconns
6263 Some servers have been found to incorrectly signal the use
6264 of HTTP/1.0 persistent connections even on replies not
6265 compatible, causing significant delays. This server problem
6266 has mostly been seen on redirects.
6268 By enabling this directive Squid attempts to detect such
6269 broken replies and automatically assume the reply is finished
6270 after 10 seconds timeout.
6274 CACHE DIGEST OPTIONS
6275 -----------------------------------------------------------------------------
6278 NAME: digest_generation
6279 IFDEF: USE_CACHE_DIGESTS
6281 LOC: Config.onoff.digest_generation
6284 This controls whether the server will generate a Cache Digest
6285 of its contents. By default, Cache Digest generation is
6286 enabled if Squid is compiled with --enable-cache-digests defined.
6289 NAME: digest_bits_per_entry
6290 IFDEF: USE_CACHE_DIGESTS
6292 LOC: Config.digest.bits_per_entry
6295 This is the number of bits of the server's Cache Digest which
6296 will be associated with the Digest entry for a given HTTP
6297 Method and URL (public key) combination. The default is 5.
6300 NAME: digest_rebuild_period
6301 IFDEF: USE_CACHE_DIGESTS
6304 LOC: Config.digest.rebuild_period
6307 This is the wait time between Cache Digest rebuilds.
6310 NAME: digest_rewrite_period
6312 IFDEF: USE_CACHE_DIGESTS
6314 LOC: Config.digest.rewrite_period
6317 This is the wait time between Cache Digest writes to
6321 NAME: digest_swapout_chunk_size
6324 IFDEF: USE_CACHE_DIGESTS
6325 LOC: Config.digest.swapout_chunk_size
6328 This is the number of bytes of the Cache Digest to write to
6329 disk at a time. It defaults to 4096 bytes (4KB), the Squid
6333 NAME: digest_rebuild_chunk_percentage
6334 COMMENT: (percent, 0-100)
6335 IFDEF: USE_CACHE_DIGESTS
6337 LOC: Config.digest.rebuild_chunk_percentage
6340 This is the percentage of the Cache Digest to be scanned at a
6341 time. By default it is set to 10% of the Cache Digest.
6346 -----------------------------------------------------------------------------
6351 LOC: Config.Port.snmp
6355 The port number where Squid listens for SNMP requests. To enable
6356 SNMP support set this to a suitable port number. Port number
6357 3401 is often used for the Squid SNMP agent. By default it's
6358 set to "0" (disabled)
6366 LOC: Config.accessList.snmp
6367 DEFAULT_IF_NONE: deny all
6370 Allowing or denying access to the SNMP port.
6372 All access to the agent is denied by default.
6375 snmp_access allow|deny [!]aclname ...
6377 This clause only supports fast acl types.
6378 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6380 snmp_access allow snmppublic localhost
6381 snmp_access deny all
6384 NAME: snmp_incoming_address
6386 LOC: Config.Addrs.snmp_incoming
6391 NAME: snmp_outgoing_address
6393 LOC: Config.Addrs.snmp_outgoing
6397 Just like 'udp_incoming_address', but for the SNMP port.
6399 snmp_incoming_address is used for the SNMP socket receiving
6400 messages from SNMP agents.
6401 snmp_outgoing_address is used for SNMP packets returned to SNMP
6404 The default snmp_incoming_address is to listen on all
6405 available network interfaces.
6407 If snmp_outgoing_address is not set it will use the same socket
6408 as snmp_incoming_address. Only change this if you want to have
6409 SNMP replies sent using another address than where this Squid
6410 listens for SNMP queries.
6412 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
6413 the same value since they both use port 3401.
6418 -----------------------------------------------------------------------------
6421 NAME: icp_port udp_port
6424 LOC: Config.Port.icp
6426 The port number where Squid sends and receives ICP queries to
6427 and from neighbor caches. The standard UDP port for ICP is 3130.
6428 Default is disabled (0).
6431 icp_port @DEFAULT_ICP_PORT@
6438 LOC: Config.Port.htcp
6440 The port number where Squid sends and receives HTCP queries to
6441 and from neighbor caches. To turn it on you want to set it to
6442 4827. By default it is set to "0" (disabled).
6448 NAME: log_icp_queries
6452 LOC: Config.onoff.log_udp
6454 If set, ICP queries are logged to access.log. You may wish
6455 do disable this if your ICP load is VERY high to speed things
6456 up or to simplify log analysis.
6459 NAME: udp_incoming_address
6461 LOC:Config.Addrs.udp_incoming
6464 udp_incoming_address is used for UDP packets received from other
6467 The default behavior is to not bind to any specific address.
6469 Only change this if you want to have all UDP queries received on
6470 a specific interface/address.
6472 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
6473 modules. Altering it will affect all of them in the same manner.
6475 see also; udp_outgoing_address
6477 NOTE, udp_incoming_address and udp_outgoing_address can not
6478 have the same value since they both use the same port.
6481 NAME: udp_outgoing_address
6483 LOC: Config.Addrs.udp_outgoing
6486 udp_outgoing_address is used for UDP packets sent out to other
6489 The default behavior is to not bind to any specific address.
6491 Instead it will use the same socket as udp_incoming_address.
6492 Only change this if you want to have UDP queries sent using another
6493 address than where this Squid listens for UDP queries from other
6496 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
6497 modules. Altering it will affect all of them in the same manner.
6499 see also; udp_incoming_address
6501 NOTE, udp_incoming_address and udp_outgoing_address can not
6502 have the same value since they both use the same port.
6509 LOC: Config.onoff.icp_hit_stale
6511 If you want to return ICP_HIT for stale cache objects, set this
6512 option to 'on'. If you have sibling relationships with caches
6513 in other administrative domains, this should be 'off'. If you only
6514 have sibling relationships with caches under your control,
6515 it is probably okay to set this to 'on'.
6516 If set to 'on', your siblings should use the option "allow-miss"
6517 on their cache_peer lines for connecting to you.
6520 NAME: minimum_direct_hops
6523 LOC: Config.minDirectHops
6525 If using the ICMP pinging stuff, do direct fetches for sites
6526 which are no more than this many hops away.
6529 NAME: minimum_direct_rtt
6532 LOC: Config.minDirectRtt
6534 If using the ICMP pinging stuff, do direct fetches for sites
6535 which are no more than this many rtt milliseconds away.
6541 LOC: Config.Netdb.low
6547 LOC: Config.Netdb.high
6549 The low and high water marks for the ICMP measurement
6550 database. These are counts, not percents. The defaults are
6551 900 and 1000. When the high water mark is reached, database
6552 entries will be deleted until the low mark is reached.
6555 NAME: netdb_ping_period
6557 LOC: Config.Netdb.period
6560 The minimum period for measuring a site. There will be at
6561 least this much delay between successive pings to the same
6562 network. The default is five minutes.
6569 LOC: Config.onoff.query_icmp
6571 If you want to ask your peers to include ICMP data in their ICP
6572 replies, enable this option.
6574 If your peer has configured Squid (during compilation) with
6575 '--enable-icmp' that peer will send ICMP pings to origin server
6576 sites of the URLs it receives. If you enable this option the
6577 ICP replies from that peer will include the ICMP data (if available).
6578 Then, when choosing a parent cache, Squid will choose the parent with
6579 the minimal RTT to the origin server. When this happens, the
6580 hierarchy field of the access.log will be
6581 "CLOSEST_PARENT_MISS". This option is off by default.
6584 NAME: test_reachability
6588 LOC: Config.onoff.test_reachability
6590 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
6591 instead of ICP_MISS if the target host is NOT in the ICMP
6592 database, or has a zero RTT.
6595 NAME: icp_query_timeout
6599 LOC: Config.Timeout.icp_query
6601 Normally Squid will automatically determine an optimal ICP
6602 query timeout value based on the round-trip-time of recent ICP
6603 queries. If you want to override the value determined by
6604 Squid, set this 'icp_query_timeout' to a non-zero value. This
6605 value is specified in MILLISECONDS, so, to use a 2-second
6606 timeout (the old default), you would write:
6608 icp_query_timeout 2000
6611 NAME: maximum_icp_query_timeout
6615 LOC: Config.Timeout.icp_query_max
6617 Normally the ICP query timeout is determined dynamically. But
6618 sometimes it can lead to very large values (say 5 seconds).
6619 Use this option to put an upper limit on the dynamic timeout
6620 value. Do NOT use this option to always use a fixed (instead
6621 of a dynamic) timeout value. To set a fixed timeout see the
6622 'icp_query_timeout' directive.
6625 NAME: minimum_icp_query_timeout
6629 LOC: Config.Timeout.icp_query_min
6631 Normally the ICP query timeout is determined dynamically. But
6632 sometimes it can lead to very small timeouts, even lower than
6633 the normal latency variance on your link due to traffic.
6634 Use this option to put an lower limit on the dynamic timeout
6635 value. Do NOT use this option to always use a fixed (instead
6636 of a dynamic) timeout value. To set a fixed timeout see the
6637 'icp_query_timeout' directive.
6640 NAME: background_ping_rate
6644 LOC: Config.backgroundPingRate
6646 Controls how often the ICP pings are sent to siblings that
6647 have background-ping set.
6651 MULTICAST ICP OPTIONS
6652 -----------------------------------------------------------------------------
6657 LOC: Config.mcast_group_list
6660 This tag specifies a list of multicast groups which your server
6661 should join to receive multicasted ICP queries.
6663 NOTE! Be very careful what you put here! Be sure you
6664 understand the difference between an ICP _query_ and an ICP
6665 _reply_. This option is to be set only if you want to RECEIVE
6666 multicast queries. Do NOT set this option to SEND multicast
6667 ICP (use cache_peer for that). ICP replies are always sent via
6668 unicast, so this option does not affect whether or not you will
6669 receive replies from multicast group members.
6671 You must be very careful to NOT use a multicast address which
6672 is already in use by another group of caches.
6674 If you are unsure about multicast, please read the Multicast
6675 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
6677 Usage: mcast_groups 239.128.16.128 224.0.1.20
6679 By default, Squid doesn't listen on any multicast groups.
6682 NAME: mcast_miss_addr
6683 IFDEF: MULTICAST_MISS_STREAM
6685 LOC: Config.mcast_miss.addr
6688 If you enable this option, every "cache miss" URL will
6689 be sent out on the specified multicast address.
6691 Do not enable this option unless you are are absolutely
6692 certain you understand what you are doing.
6695 NAME: mcast_miss_ttl
6696 IFDEF: MULTICAST_MISS_STREAM
6698 LOC: Config.mcast_miss.ttl
6701 This is the time-to-live value for packets multicasted
6702 when multicasting off cache miss URLs is enabled. By
6703 default this is set to 'site scope', i.e. 16.
6706 NAME: mcast_miss_port
6707 IFDEF: MULTICAST_MISS_STREAM
6709 LOC: Config.mcast_miss.port
6712 This is the port number to be used in conjunction with
6716 NAME: mcast_miss_encode_key
6717 IFDEF: MULTICAST_MISS_STREAM
6719 LOC: Config.mcast_miss.encode_key
6720 DEFAULT: XXXXXXXXXXXXXXXX
6722 The URLs that are sent in the multicast miss stream are
6723 encrypted. This is the encryption key.
6726 NAME: mcast_icp_query_timeout
6730 LOC: Config.Timeout.mcast_icp_query
6732 For multicast peers, Squid regularly sends out ICP "probes" to
6733 count how many other peers are listening on the given multicast
6734 address. This value specifies how long Squid should wait to
6735 count all the replies. The default is 2000 msec, or 2
6740 INTERNAL ICON OPTIONS
6741 -----------------------------------------------------------------------------
6744 NAME: icon_directory
6746 LOC: Config.icons.directory
6747 DEFAULT: @DEFAULT_ICON_DIR@
6749 Where the icons are stored. These are normally kept in
6753 NAME: global_internal_static
6755 LOC: Config.onoff.global_internal_static
6758 This directive controls is Squid should intercept all requests for
6759 /squid-internal-static/ no matter which host the URL is requesting
6760 (default on setting), or if nothing special should be done for
6761 such URLs (off setting). The purpose of this directive is to make
6762 icons etc work better in complex cache hierarchies where it may
6763 not always be possible for all corners in the cache mesh to reach
6764 the server generating a directory listing.
6767 NAME: short_icon_urls
6769 LOC: Config.icons.use_short_names
6772 If this is enabled Squid will use short URLs for icons.
6773 If disabled it will revert to the old behavior of including
6774 it's own name and port in the URL.
6776 If you run a complex cache hierarchy with a mix of Squid and
6777 other proxies you may need to disable this directive.
6782 -----------------------------------------------------------------------------
6785 NAME: error_directory
6787 LOC: Config.errorDirectory
6790 If you wish to create your own versions of the default
6791 error files to customize them to suit your company copy
6792 the error/template files to another directory and point
6795 WARNING: This option will disable multi-language support
6796 on error pages if used.
6798 The squid developers are interested in making squid available in
6799 a wide variety of languages. If you are making translations for a
6800 language that Squid does not currently provide please consider
6801 contributing your translation back to the project.
6802 http://wiki.squid-cache.org/Translations
6804 The squid developers working on translations are happy to supply drop-in
6805 translated error files in exchange for any new language contributions.
6808 NAME: error_default_language
6809 IFDEF: USE_ERR_LOCALES
6811 LOC: Config.errorDefaultLanguage
6814 Set the default language which squid will send error pages in
6815 if no existing translation matches the clients language
6818 If unset (default) generic English will be used.
6820 The squid developers are interested in making squid available in
6821 a wide variety of languages. If you are interested in making
6822 translations for any language see the squid wiki for details.
6823 http://wiki.squid-cache.org/Translations
6826 NAME: error_log_languages
6827 IFDEF: USE_ERR_LOCALES
6829 LOC: Config.errorLogMissingLanguages
6832 Log to cache.log what languages users are attempting to
6833 auto-negotiate for translations.
6835 Successful negotiations are not logged. Only failures
6836 have meaning to indicate that Squid may need an upgrade
6837 of its error page translations.
6840 NAME: err_page_stylesheet
6842 LOC: Config.errorStylesheet
6843 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
6845 CSS Stylesheet to pattern the display of Squid default error pages.
6847 For information on CSS see http://www.w3.org/Style/CSS/
6852 LOC: Config.errHtmlText
6855 HTML text to include in error messages. Make this a "mailto"
6856 URL to your admin address, or maybe just a link to your
6857 organizations Web page.
6859 To include this in your error messages, you must rewrite
6860 the error template files (found in the "errors" directory).
6861 Wherever you want the 'err_html_text' line to appear,
6862 insert a %L tag in the error template file.
6865 NAME: email_err_data
6868 LOC: Config.onoff.emailErrData
6871 If enabled, information about the occurred error will be
6872 included in the mailto links of the ERR pages (if %W is set)
6873 so that the email body contains the data.
6874 Syntax is <A HREF="mailto:%w%W">%w</A>
6879 LOC: Config.denyInfoList
6882 Usage: deny_info err_page_name acl
6883 or deny_info http://... acl
6884 or deny_info TCP_RESET acl
6886 This can be used to return a ERR_ page for requests which
6887 do not pass the 'http_access' rules. Squid remembers the last
6888 acl it evaluated in http_access, and if a 'deny_info' line exists
6889 for that ACL Squid returns a corresponding error page.
6891 The acl is typically the last acl on the http_access deny line which
6892 denied access. The exceptions to this rule are:
6893 - When Squid needs to request authentication credentials. It's then
6894 the first authentication related acl encountered
6895 - When none of the http_access lines matches. It's then the last
6896 acl processed on the last http_access line.
6897 - When the decision to deny access was made by an adaptation service,
6898 the acl name is the corresponding eCAP or ICAP service_name.
6900 NP: If providing your own custom error pages with error_directory
6901 you may also specify them by your custom file name:
6902 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
6904 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
6905 may be specified by prefixing the file name with the code and a colon.
6906 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
6908 Alternatively you can tell Squid to reset the TCP connection
6909 by specifying TCP_RESET.
6911 Or you can specify an error URL or URL pattern. The browsers will
6912 get redirected to the specified URL after formatting tags have
6913 been replaced. Redirect will be done with 302 or 307 according to
6914 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
6915 the URL. e.g. 303:http://example.com/
6918 %a - username (if available. Password NOT included)
6921 %E - Error description
6923 %H - Request domain name
6924 %i - Client IP Address
6926 %o - Message result from external ACL helper
6927 %p - Request Port number
6928 %P - Request Protocol name
6929 %R - Request URL path
6930 %T - Timestamp in RFC 1123 format
6931 %U - Full canonical URL from client
6932 (HTTPS URLs terminate with *)
6933 %u - Full canonical URL from client
6934 %w - Admin email from squid.conf
6936 %% - Literal percent (%) code
6941 OPTIONS INFLUENCING REQUEST FORWARDING
6942 -----------------------------------------------------------------------------
6945 NAME: nonhierarchical_direct
6947 LOC: Config.onoff.nonhierarchical_direct
6950 By default, Squid will send any non-hierarchical requests
6951 (matching hierarchy_stoplist or not cacheable request type) direct
6954 If you set this to off, Squid will prefer to send these
6955 requests to parents.
6957 Note that in most configurations, by turning this off you will only
6958 add latency to these request without any improvement in global hit
6961 If you are inside an firewall see never_direct instead of
6967 LOC: Config.onoff.prefer_direct
6970 Normally Squid tries to use parents for most requests. If you for some
6971 reason like it to first try going direct and only use a parent if
6972 going direct fails set this to on.
6974 By combining nonhierarchical_direct off and prefer_direct on you
6975 can set up Squid to use a parent as a backup path if going direct
6978 Note: If you want Squid to use parents for all requests see
6979 the never_direct directive. prefer_direct only modifies how Squid
6980 acts on cacheable requests.
6985 LOC: Config.accessList.AlwaysDirect
6988 Usage: always_direct allow|deny [!]aclname ...
6990 Here you can use ACL elements to specify requests which should
6991 ALWAYS be forwarded by Squid to the origin servers without using
6992 any peers. For example, to always directly forward requests for
6993 local servers ignoring any parents or siblings you may have use
6996 acl local-servers dstdomain my.domain.net
6997 always_direct allow local-servers
6999 To always forward FTP requests directly, use
7002 always_direct allow FTP
7004 NOTE: There is a similar, but opposite option named
7005 'never_direct'. You need to be aware that "always_direct deny
7006 foo" is NOT the same thing as "never_direct allow foo". You
7007 may need to use a deny rule to exclude a more-specific case of
7008 some other rule. Example:
7010 acl local-external dstdomain external.foo.net
7011 acl local-servers dstdomain .foo.net
7012 always_direct deny local-external
7013 always_direct allow local-servers
7015 NOTE: If your goal is to make the client forward the request
7016 directly to the origin server bypassing Squid then this needs
7017 to be done in the client configuration. Squid configuration
7018 can only tell Squid how Squid should fetch the object.
7020 NOTE: This directive is not related to caching. The replies
7021 is cached as usual even if you use always_direct. To not cache
7022 the replies see the 'cache' directive.
7024 This clause supports both fast and slow acl types.
7025 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7030 LOC: Config.accessList.NeverDirect
7033 Usage: never_direct allow|deny [!]aclname ...
7035 never_direct is the opposite of always_direct. Please read
7036 the description for always_direct if you have not already.
7038 With 'never_direct' you can use ACL elements to specify
7039 requests which should NEVER be forwarded directly to origin
7040 servers. For example, to force the use of a proxy for all
7041 requests, except those in your local domain use something like:
7043 acl local-servers dstdomain .foo.net
7044 never_direct deny local-servers
7045 never_direct allow all
7047 or if Squid is inside a firewall and there are local intranet
7048 servers inside the firewall use something like:
7050 acl local-intranet dstdomain .foo.net
7051 acl local-external dstdomain external.foo.net
7052 always_direct deny local-external
7053 always_direct allow local-intranet
7054 never_direct allow all
7056 This clause supports both fast and slow acl types.
7057 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7061 ADVANCED NETWORKING OPTIONS
7062 -----------------------------------------------------------------------------
7065 NAME: incoming_udp_average incoming_icp_average
7068 LOC: Config.comm_incoming.udp.average
7070 Heavy voodoo here. I can't even believe you are reading this.
7071 Are you crazy? Don't even think about adjusting these unless
7072 you understand the algorithms in comm_select.c first!
7075 NAME: incoming_tcp_average incoming_http_average
7078 LOC: Config.comm_incoming.tcp.average
7080 Heavy voodoo here. I can't even believe you are reading this.
7081 Are you crazy? Don't even think about adjusting these unless
7082 you understand the algorithms in comm_select.c first!
7085 NAME: incoming_dns_average
7088 LOC: Config.comm_incoming.dns.average
7090 Heavy voodoo here. I can't even believe you are reading this.
7091 Are you crazy? Don't even think about adjusting these unless
7092 you understand the algorithms in comm_select.c first!
7095 NAME: min_udp_poll_cnt min_icp_poll_cnt
7098 LOC: Config.comm_incoming.udp.min_poll
7100 Heavy voodoo here. I can't even believe you are reading this.
7101 Are you crazy? Don't even think about adjusting these unless
7102 you understand the algorithms in comm_select.c first!
7105 NAME: min_dns_poll_cnt
7108 LOC: Config.comm_incoming.dns.min_poll
7110 Heavy voodoo here. I can't even believe you are reading this.
7111 Are you crazy? Don't even think about adjusting these unless
7112 you understand the algorithms in comm_select.c first!
7115 NAME: min_tcp_poll_cnt min_http_poll_cnt
7118 LOC: Config.comm_incoming.tcp.min_poll
7120 Heavy voodoo here. I can't even believe you are reading this.
7121 Are you crazy? Don't even think about adjusting these unless
7122 you understand the algorithms in comm_select.c first!
7128 LOC: Config.accept_filter
7132 The name of an accept(2) filter to install on Squid's
7133 listen socket(s). This feature is perhaps specific to
7134 FreeBSD and requires support in the kernel.
7136 The 'httpready' filter delays delivering new connections
7137 to Squid until a full HTTP request has been received.
7138 See the accf_http(9) man page for details.
7140 The 'dataready' filter delays delivering new connections
7141 to Squid until there is some data to process.
7142 See the accf_dataready(9) man page for details.
7146 The 'data' filter delays delivering of new connections
7147 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
7148 You may optionally specify a number of seconds to wait by
7149 'data=N' where N is the number of seconds. Defaults to 30
7150 if not specified. See the tcp(7) man page for details.
7153 accept_filter httpready
7158 NAME: client_ip_max_connections
7160 LOC: Config.client_ip_max_connections
7163 Set an absolute limit on the number of connections a single
7164 client IP can use. Any more than this and Squid will begin to drop
7165 new connections from the client until it closes some links.
7167 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
7168 connections from the client. For finer control use the ACL access controls.
7170 Requires client_db to be enabled (the default).
7172 WARNING: This may noticably slow down traffic received via external proxies
7173 or NAT devices and cause them to rebound error messages back to their clients.
7176 NAME: tcp_recv_bufsize
7180 LOC: Config.tcpRcvBufsz
7182 Size of receive buffer to set for TCP sockets. Probably just
7183 as easy to change your kernel's default. Set to zero to use
7184 the default buffer size.
7189 -----------------------------------------------------------------------------
7196 LOC: Adaptation::Icap::TheConfig.onoff
7199 If you want to enable the ICAP module support, set this to on.
7202 NAME: icap_connect_timeout
7205 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
7208 This parameter specifies how long to wait for the TCP connect to
7209 the requested ICAP server to complete before giving up and either
7210 terminating the HTTP transaction or bypassing the failure.
7212 The default for optional services is peer_connect_timeout.
7213 The default for essential services is connect_timeout.
7214 If this option is explicitly set, its value applies to all services.
7217 NAME: icap_io_timeout
7221 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
7224 This parameter specifies how long to wait for an I/O activity on
7225 an established, active ICAP connection before giving up and
7226 either terminating the HTTP transaction or bypassing the
7229 The default is read_timeout.
7232 NAME: icap_service_failure_limit
7233 COMMENT: limit [in memory-depth time-units]
7234 TYPE: icap_service_failure_limit
7236 LOC: Adaptation::Icap::TheConfig
7239 The limit specifies the number of failures that Squid tolerates
7240 when establishing a new TCP connection with an ICAP service. If
7241 the number of failures exceeds the limit, the ICAP service is
7242 not used for new ICAP requests until it is time to refresh its
7245 A negative value disables the limit. Without the limit, an ICAP
7246 service will not be considered down due to connectivity failures
7247 between ICAP OPTIONS requests.
7249 Squid forgets ICAP service failures older than the specified
7250 value of memory-depth. The memory fading algorithm
7251 is approximate because Squid does not remember individual
7252 errors but groups them instead, splitting the option
7253 value into ten time slots of equal length.
7255 When memory-depth is 0 and by default this option has no
7256 effect on service failure expiration.
7258 Squid always forgets failures when updating service settings
7259 using an ICAP OPTIONS transaction, regardless of this option
7263 # suspend service usage after 10 failures in 5 seconds:
7264 icap_service_failure_limit 10 in 5 seconds
7267 NAME: icap_service_revival_delay
7270 LOC: Adaptation::Icap::TheConfig.service_revival_delay
7273 The delay specifies the number of seconds to wait after an ICAP
7274 OPTIONS request failure before requesting the options again. The
7275 failed ICAP service is considered "down" until fresh OPTIONS are
7278 The actual delay cannot be smaller than the hardcoded minimum
7279 delay of 30 seconds.
7282 NAME: icap_preview_enable
7286 LOC: Adaptation::Icap::TheConfig.preview_enable
7289 The ICAP Preview feature allows the ICAP server to handle the
7290 HTTP message by looking only at the beginning of the message body
7291 or even without receiving the body at all. In some environments,
7292 previews greatly speedup ICAP processing.
7294 During an ICAP OPTIONS transaction, the server may tell Squid what
7295 HTTP messages should be previewed and how big the preview should be.
7296 Squid will not use Preview if the server did not request one.
7298 To disable ICAP Preview for all ICAP services, regardless of
7299 individual ICAP server OPTIONS responses, set this option to "off".
7301 icap_preview_enable off
7304 NAME: icap_preview_size
7307 LOC: Adaptation::Icap::TheConfig.preview_size
7310 The default size of preview data to be sent to the ICAP server.
7311 -1 means no preview. This value might be overwritten on a per server
7312 basis by OPTIONS requests.
7315 NAME: icap_206_enable
7319 LOC: Adaptation::Icap::TheConfig.allow206_enable
7322 206 (Partial Content) responses is an ICAP extension that allows the
7323 ICAP agents to optionally combine adapted and original HTTP message
7324 content. The decision to combine is postponed until the end of the
7325 ICAP response. Squid supports Partial Content extension by default.
7327 Activation of the Partial Content extension is negotiated with each
7328 ICAP service during OPTIONS exchange. Most ICAP servers should handle
7329 negotation correctly even if they do not support the extension, but
7330 some might fail. To disable Partial Content support for all ICAP
7331 services and to avoid any negotiation, set this option to "off".
7337 NAME: icap_default_options_ttl
7340 LOC: Adaptation::Icap::TheConfig.default_options_ttl
7343 The default TTL value for ICAP OPTIONS responses that don't have
7344 an Options-TTL header.
7347 NAME: icap_persistent_connections
7351 LOC: Adaptation::Icap::TheConfig.reuse_connections
7354 Whether or not Squid should use persistent connections to
7358 NAME: adaptation_send_client_ip icap_send_client_ip
7360 IFDEF: USE_ADAPTATION
7362 LOC: Adaptation::Config::send_client_ip
7365 If enabled, Squid shares HTTP client IP information with adaptation
7366 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
7367 For eCAP, Squid sets the libecap::metaClientIp transaction option.
7369 See also: adaptation_uses_indirect_client
7372 NAME: adaptation_send_username icap_send_client_username
7374 IFDEF: USE_ADAPTATION
7376 LOC: Adaptation::Config::send_username
7379 This sends authenticated HTTP client username (if available) to
7380 the adaptation service.
7382 For ICAP, the username value is encoded based on the
7383 icap_client_username_encode option and is sent using the header
7384 specified by the icap_client_username_header option.
7387 NAME: icap_client_username_header
7390 LOC: Adaptation::Icap::TheConfig.client_username_header
7391 DEFAULT: X-Client-Username
7393 ICAP request header name to use for adaptation_send_username.
7396 NAME: icap_client_username_encode
7400 LOC: Adaptation::Icap::TheConfig.client_username_encode
7403 Whether to base64 encode the authenticated client username.
7407 TYPE: icap_service_type
7409 LOC: Adaptation::Icap::TheConfig
7412 Defines a single ICAP service using the following format:
7414 icap_service id vectoring_point uri [option ...]
7417 an opaque identifier or name which is used to direct traffic to
7418 this specific service. Must be unique among all adaptation
7419 services in squid.conf.
7421 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7422 This specifies at which point of transaction processing the
7423 ICAP service should be activated. *_postcache vectoring points
7424 are not yet supported.
7426 uri: icap://servername:port/servicepath
7427 ICAP server and service location.
7429 ICAP does not allow a single service to handle both REQMOD and RESPMOD
7430 transactions. Squid does not enforce that requirement. You can specify
7431 services with the same service_url and different vectoring_points. You
7432 can even specify multiple identical services as long as their
7433 service_names differ.
7436 Service options are separated by white space. ICAP services support
7437 the following name=value options:
7440 If set to 'on' or '1', the ICAP service is treated as
7441 optional. If the service cannot be reached or malfunctions,
7442 Squid will try to ignore any errors and process the message as
7443 if the service was not enabled. No all ICAP errors can be
7444 bypassed. If set to 0, the ICAP service is treated as
7445 essential and all ICAP errors will result in an error page
7446 returned to the HTTP client.
7448 Bypass is off by default: services are treated as essential.
7451 If set to 'on' or '1', the ICAP service is allowed to
7452 dynamically change the current message adaptation plan by
7453 returning a chain of services to be used next. The services
7454 are specified using the X-Next-Services ICAP response header
7455 value, formatted as a comma-separated list of service names.
7456 Each named service should be configured in squid.conf. Other
7457 services are ignored. An empty X-Next-Services value results
7458 in an empty plan which ends the current adaptation.
7460 Dynamic adaptation plan may cross or cover multiple supported
7461 vectoring points in their natural processing order.
7463 Routing is not allowed by default: the ICAP X-Next-Services
7464 response header is ignored.
7467 Only has effect on split-stack systems. The default on those systems
7468 is to use IPv4-only connections. When set to 'on' this option will
7469 make Squid use IPv6-only connections to contact this ICAP service.
7471 on-overload=block|bypass|wait|force
7472 If the service Max-Connections limit has been reached, do
7473 one of the following for each new ICAP transaction:
7474 * block: send an HTTP error response to the client
7475 * bypass: ignore the "over-connected" ICAP service
7476 * wait: wait (in a FIFO queue) for an ICAP connection slot
7477 * force: proceed, ignoring the Max-Connections limit
7479 In SMP mode with N workers, each worker assumes the service
7480 connection limit is Max-Connections/N, even though not all
7481 workers may use a given service.
7483 The default value is "bypass" if service is bypassable,
7484 otherwise it is set to "wait".
7488 Use the given number as the Max-Connections limit, regardless
7489 of the Max-Connections value given by the service, if any.
7491 Older icap_service format without optional named parameters is
7492 deprecated but supported for backward compatibility.
7495 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
7496 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
7500 TYPE: icap_class_type
7505 This deprecated option was documented to define an ICAP service
7506 chain, even though it actually defined a set of similar, redundant
7507 services, and the chains were not supported.
7509 To define a set of redundant services, please use the
7510 adaptation_service_set directive. For service chains, use
7511 adaptation_service_chain.
7515 TYPE: icap_access_type
7520 This option is deprecated. Please use adaptation_access, which
7521 has the same ICAP functionality, but comes with better
7522 documentation, and eCAP support.
7527 -----------------------------------------------------------------------------
7534 LOC: Adaptation::Ecap::TheConfig.onoff
7537 Controls whether eCAP support is enabled.
7541 TYPE: ecap_service_type
7543 LOC: Adaptation::Ecap::TheConfig
7546 Defines a single eCAP service
7548 ecap_service id vectoring_point uri [option ...]
7551 an opaque identifier or name which is used to direct traffic to
7552 this specific service. Must be unique among all adaptation
7553 services in squid.conf.
7555 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7556 This specifies at which point of transaction processing the
7557 eCAP service should be activated. *_postcache vectoring points
7558 are not yet supported.
7560 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
7561 Squid uses the eCAP service URI to match this configuration
7562 line with one of the dynamically loaded services. Each loaded
7563 eCAP service must have a unique URI. Obtain the right URI from
7564 the service provider.
7567 Service options are separated by white space. eCAP services support
7568 the following name=value options:
7571 If set to 'on' or '1', the eCAP service is treated as optional.
7572 If the service cannot be reached or malfunctions, Squid will try
7573 to ignore any errors and process the message as if the service
7574 was not enabled. No all eCAP errors can be bypassed.
7575 If set to 'off' or '0', the eCAP service is treated as essential
7576 and all eCAP errors will result in an error page returned to the
7579 Bypass is off by default: services are treated as essential.
7582 If set to 'on' or '1', the eCAP service is allowed to
7583 dynamically change the current message adaptation plan by
7584 returning a chain of services to be used next.
7586 Dynamic adaptation plan may cross or cover multiple supported
7587 vectoring points in their natural processing order.
7589 Routing is not allowed by default.
7591 Older ecap_service format without optional named parameters is
7592 deprecated but supported for backward compatibility.
7596 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
7597 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
7600 NAME: loadable_modules
7602 IFDEF: USE_LOADABLE_MODULES
7603 LOC: Config.loadable_module_names
7606 Instructs Squid to load the specified dynamic module(s) or activate
7607 preloaded module(s).
7609 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
7613 MESSAGE ADAPTATION OPTIONS
7614 -----------------------------------------------------------------------------
7617 NAME: adaptation_service_set
7618 TYPE: adaptation_service_set_type
7619 IFDEF: USE_ADAPTATION
7624 Configures an ordered set of similar, redundant services. This is
7625 useful when hot standby or backup adaptation servers are available.
7627 adaptation_service_set set_name service_name1 service_name2 ...
7629 The named services are used in the set declaration order. The first
7630 applicable adaptation service from the set is used first. The next
7631 applicable service is tried if and only if the transaction with the
7632 previous service fails and the message waiting to be adapted is still
7635 When adaptation starts, broken services are ignored as if they were
7636 not a part of the set. A broken service is a down optional service.
7638 The services in a set must be attached to the same vectoring point
7639 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7641 If all services in a set are optional then adaptation failures are
7642 bypassable. If all services in the set are essential, then a
7643 transaction failure with one service may still be retried using
7644 another service from the set, but when all services fail, the master
7645 transaction fails as well.
7647 A set may contain a mix of optional and essential services, but that
7648 is likely to lead to surprising results because broken services become
7649 ignored (see above), making previously bypassable failures fatal.
7650 Technically, it is the bypassability of the last failed service that
7653 See also: adaptation_access adaptation_service_chain
7656 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
7657 adaptation service_set svcLogger loggerLocal loggerRemote
7660 NAME: adaptation_service_chain
7661 TYPE: adaptation_service_chain_type
7662 IFDEF: USE_ADAPTATION
7667 Configures a list of complementary services that will be applied
7668 one-by-one, forming an adaptation chain or pipeline. This is useful
7669 when Squid must perform different adaptations on the same message.
7671 adaptation_service_chain chain_name service_name1 svc_name2 ...
7673 The named services are used in the chain declaration order. The first
7674 applicable adaptation service from the chain is used first. The next
7675 applicable service is applied to the successful adaptation results of
7676 the previous service in the chain.
7678 When adaptation starts, broken services are ignored as if they were
7679 not a part of the chain. A broken service is a down optional service.
7681 Request satisfaction terminates the adaptation chain because Squid
7682 does not currently allow declaration of RESPMOD services at the
7683 "reqmod_precache" vectoring point (see icap_service or ecap_service).
7685 The services in a chain must be attached to the same vectoring point
7686 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7688 A chain may contain a mix of optional and essential services. If an
7689 essential adaptation fails (or the failure cannot be bypassed for
7690 other reasons), the master transaction fails. Otherwise, the failure
7691 is bypassed as if the failed adaptation service was not in the chain.
7693 See also: adaptation_access adaptation_service_set
7696 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
7699 NAME: adaptation_access
7700 TYPE: adaptation_access_type
7701 IFDEF: USE_ADAPTATION
7705 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
7707 adaptation_access service_name allow|deny [!]aclname...
7708 adaptation_access set_name allow|deny [!]aclname...
7710 At each supported vectoring point, the adaptation_access
7711 statements are processed in the order they appear in this
7712 configuration file. Statements pointing to the following services
7713 are ignored (i.e., skipped without checking their ACL):
7715 - services serving different vectoring points
7716 - "broken-but-bypassable" services
7717 - "up" services configured to ignore such transactions
7718 (e.g., based on the ICAP Transfer-Ignore header).
7720 When a set_name is used, all services in the set are checked
7721 using the same rules, to find the first applicable one. See
7722 adaptation_service_set for details.
7724 If an access list is checked and there is a match, the
7725 processing stops: For an "allow" rule, the corresponding
7726 adaptation service is used for the transaction. For a "deny"
7727 rule, no adaptation service is activated.
7729 It is currently not possible to apply more than one adaptation
7730 service at the same vectoring point to the same HTTP transaction.
7732 See also: icap_service and ecap_service
7735 adaptation_access service_1 allow all
7738 NAME: adaptation_service_iteration_limit
7740 IFDEF: USE_ADAPTATION
7741 LOC: Adaptation::Config::service_iteration_limit
7744 Limits the number of iterations allowed when applying adaptation
7745 services to a message. If your longest adaptation set or chain
7746 may have more than 16 services, increase the limit beyond its
7747 default value of 16. If detecting infinite iteration loops sooner
7748 is critical, make the iteration limit match the actual number
7749 of services in your longest adaptation set or chain.
7751 Infinite adaptation loops are most likely with routing services.
7753 See also: icap_service routing=1
7756 NAME: adaptation_masterx_shared_names
7758 IFDEF: USE_ADAPTATION
7759 LOC: Adaptation::Config::masterx_shared_name
7762 For each master transaction (i.e., the HTTP request and response
7763 sequence, including all related ICAP and eCAP exchanges), Squid
7764 maintains a table of metadata. The table entries are (name, value)
7765 pairs shared among eCAP and ICAP exchanges. The table is destroyed
7766 with the master transaction.
7768 This option specifies the table entry names that Squid must accept
7769 from and forward to the adaptation transactions.
7771 An ICAP REQMOD or RESPMOD transaction may set an entry in the
7772 shared table by returning an ICAP header field with a name
7773 specified in adaptation_masterx_shared_names.
7775 An eCAP REQMOD or RESPMOD transaction may set an entry in the
7776 shared table by implementing the libecap::visitEachOption() API
7777 to provide an option with a name specified in
7778 adaptation_masterx_shared_names.
7780 Squid will store and forward the set entry to subsequent adaptation
7781 transactions within the same master transaction scope.
7783 Only one shared entry name is supported at this time.
7786 # share authentication information among ICAP services
7787 adaptation_masterx_shared_names X-Subscriber-ID
7790 NAME: adaptation_meta
7792 IFDEF: USE_ADAPTATION
7793 LOC: Adaptation::Config::metaHeaders
7796 This option allows Squid administrator to add custom ICAP request
7797 headers or eCAP options to Squid ICAP requests or eCAP transactions.
7798 Use it to pass custom authentication tokens and other
7799 transaction-state related meta information to an ICAP/eCAP service.
7801 The addition of a meta header is ACL-driven:
7802 adaptation_meta name value [!]aclname ...
7804 Processing for a given header name stops after the first ACL list match.
7805 Thus, it is impossible to add two headers with the same name. If no ACL
7806 lists match for a given header name, no such header is added. For
7809 # do not debug transactions except for those that need debugging
7810 adaptation_meta X-Debug 1 needs_debugging
7812 # log all transactions except for those that must remain secret
7813 adaptation_meta X-Log 1 !keep_secret
7815 # mark transactions from users in the "G 1" group
7816 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
7818 The "value" parameter may be a regular squid.conf token or a "double
7819 quoted string". Within the quoted string, use backslash (\) to escape
7820 any character, which is currently only useful for escaping backslashes
7821 and double quotes. For example,
7822 "this string has one backslash (\\) and two \"quotes\""
7824 Used adaptation_meta header values may be logged via %note
7825 logformat code. If multiple adaptation_meta headers with the same name
7826 are used during master transaction lifetime, the header values are
7827 logged in the order they were used and duplicate values are ignored
7828 (only the first repeated value will be logged).
7834 LOC: Adaptation::Icap::TheConfig.repeat
7835 DEFAULT_IF_NONE: deny all
7837 This ACL determines which retriable ICAP transactions are
7838 retried. Transactions that received a complete ICAP response
7839 and did not have to consume or produce HTTP bodies to receive
7840 that response are usually retriable.
7842 icap_retry allow|deny [!]aclname ...
7844 Squid automatically retries some ICAP I/O timeouts and errors
7845 due to persistent connection race conditions.
7847 See also: icap_retry_limit
7850 NAME: icap_retry_limit
7853 LOC: Adaptation::Icap::TheConfig.repeat_limit
7856 Limits the number of retries allowed. When set to zero (default),
7857 no retries are allowed.
7859 Communication errors due to persistent connection race
7860 conditions are unavoidable, automatically retried, and do not
7861 count against this limit.
7863 See also: icap_retry
7869 -----------------------------------------------------------------------------
7872 NAME: check_hostnames
7875 LOC: Config.onoff.check_hostnames
7877 For security and stability reasons Squid can check
7878 hostnames for Internet standard RFC compliance. If you want
7879 Squid to perform these checks turn this directive on.
7882 NAME: allow_underscore
7885 LOC: Config.onoff.allow_underscore
7887 Underscore characters is not strictly allowed in Internet hostnames
7888 but nevertheless used by many sites. Set this to off if you want
7889 Squid to be strict about the standard.
7890 This check is performed only when check_hostnames is set to on.
7893 NAME: cache_dns_program
7895 IFDEF: USE_DNSHELPER
7896 DEFAULT: @DEFAULT_DNSSERVER@
7897 LOC: Config.Program.dnsserver
7899 Specify the location of the executable for dnslookup process.
7903 TYPE: HelperChildConfig
7904 IFDEF: USE_DNSHELPER
7905 DEFAULT: 32 startup=1 idle=1
7906 LOC: Config.dnsChildren
7908 The maximum number of processes spawn to service DNS name lookups.
7909 If you limit it too few Squid will have to wait for them to process
7910 a backlog of requests, slowing it down. If you allow too many they
7911 will use RAM and other system resources noticably.
7912 The maximum this may be safely set to is 32.
7914 The startup= and idle= options allow some measure of skew in your
7919 Sets a minimum of how many processes are to be spawned when Squid
7920 starts or reconfigures. When set to zero the first request will
7921 cause spawning of the first child process to handle it.
7923 Starting too few will cause an initial slowdown in traffic as Squid
7924 attempts to simultaneously spawn enough processes to cope.
7928 Sets a minimum of how many processes Squid is to try and keep available
7929 at all times. When traffic begins to rise above what the existing
7930 processes can handle this many more will be spawned up to the maximum
7931 configured. A minimum setting of 1 is required.
7934 NAME: dns_retransmit_interval
7937 LOC: Config.Timeout.idns_retransmit
7938 IFDEF: !USE_DNSHELPER
7940 Initial retransmit interval for DNS queries. The interval is
7941 doubled each time all configured DNS servers have been tried.
7947 LOC: Config.Timeout.idns_query
7948 IFDEF: !USE_DNSHELPER
7950 DNS Query timeout. If no response is received to a DNS query
7951 within this time all DNS servers for the queried domain
7952 are assumed to be unavailable.
7955 NAME: dns_packet_max
7958 LOC: Config.dns.packet_max
7959 IFDEF: !USE_DNSHELPER
7961 Maximum number of bytes packet size to advertise via EDNS.
7962 Set to "none" to disable EDNS large packet support.
7964 For legacy reasons DNS UDP replies will default to 512 bytes which
7965 is too small for many responses. EDNS provides a means for Squid to
7966 negotiate receiving larger responses back immediately without having
7967 to failover with repeat requests. Responses larger than this limit
7968 will retain the old behaviour of failover to TCP DNS.
7970 Squid has no real fixed limit internally, but allowing packet sizes
7971 over 1500 bytes requires network jumbogram support and is usually not
7974 WARNING: The RFC also indicates that some older resolvers will reply
7975 with failure of the whole request if the extension is added. Some
7976 resolvers have already been identified which will reply with mangled
7977 EDNS response on occasion. Usually in response to many-KB jumbogram
7978 sizes being advertised by Squid.
7979 Squid will currently treat these both as an unable-to-resolve domain
7980 even if it would be resolvable without EDNS.
7987 LOC: Config.onoff.res_defnames
7989 Normally the RES_DEFNAMES resolver option is disabled
7990 (see res_init(3)). This prevents caches in a hierarchy
7991 from interpreting single-component hostnames locally. To allow
7992 Squid to handle single-component names, enable this option.
7995 NAME: dns_nameservers
7998 LOC: Config.dns_nameservers
8000 Use this if you want to specify a list of DNS name servers
8001 (IP addresses) to use instead of those given in your
8002 /etc/resolv.conf file.
8003 On Windows platforms, if no value is specified here or in
8004 the /etc/resolv.conf file, the list of DNS name servers are
8005 taken from the Windows registry, both static and dynamic DHCP
8006 configurations are supported.
8008 Example: dns_nameservers 10.0.0.1 192.172.0.4
8013 DEFAULT: @DEFAULT_HOSTS@
8014 LOC: Config.etcHostsPath
8016 Location of the host-local IP name-address associations
8017 database. Most Operating Systems have such a file on different
8019 - Un*X & Linux: /etc/hosts
8020 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
8021 (%SystemRoot% value install default is c:\winnt)
8022 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
8023 (%SystemRoot% value install default is c:\windows)
8024 - Windows 9x/Me: %windir%\hosts
8025 (%windir% value is usually c:\windows)
8026 - Cygwin: /etc/hosts
8028 The file contains newline-separated definitions, in the
8029 form ip_address_in_dotted_form name [name ...] names are
8030 whitespace-separated. Lines beginning with an hash (#)
8031 character are comments.
8033 The file is checked at startup and upon configuration.
8034 If set to 'none', it won't be checked.
8035 If append_domain is used, that domain will be added to
8036 domain-local (i.e. not containing any dot character) host
8042 LOC: Config.appendDomain
8045 Appends local domain name to hostnames without any dots in
8046 them. append_domain must begin with a period.
8048 Be warned there are now Internet names with no dots in
8049 them using only top-domain names, so setting this may
8050 cause some Internet sites to become unavailable.
8053 append_domain .yourdomain.com
8056 NAME: ignore_unknown_nameservers
8058 LOC: Config.onoff.ignore_unknown_nameservers
8060 IFDEF: !USE_DNSHELPER
8062 By default Squid checks that DNS responses are received
8063 from the same IP addresses they are sent to. If they
8064 don't match, Squid ignores the response and writes a warning
8065 message to cache.log. You can allow responses from unknown
8066 nameservers by setting this option to 'off'.
8072 LOC: Config.dns.v4_first
8073 IFDEF: !USE_DNSHELPER
8075 With the IPv6 Internet being as fast or faster than IPv4 Internet
8076 for most networks Squid prefers to contact websites over IPv6.
8078 This option reverses the order of preference to make Squid contact
8079 dual-stack websites over IPv4 first. Squid will still perform both
8080 IPv6 and IPv4 DNS lookups before connecting.
8083 This option will restrict the situations under which IPv6
8084 connectivity is used (and tested). Hiding network problems
8085 which would otherwise be detected and warned about.
8089 COMMENT: (number of entries)
8092 LOC: Config.ipcache.size
8099 LOC: Config.ipcache.low
8106 LOC: Config.ipcache.high
8108 The size, low-, and high-water marks for the IP cache.
8111 NAME: fqdncache_size
8112 COMMENT: (number of entries)
8115 LOC: Config.fqdncache.size
8117 Maximum number of FQDN cache entries.
8122 -----------------------------------------------------------------------------
8129 LOC: Config.onoff.mem_pools
8131 If set, Squid will keep pools of allocated (but unused) memory
8132 available for future use. If memory is a premium on your
8133 system and you believe your malloc library outperforms Squid
8134 routines, disable this.
8137 NAME: memory_pools_limit
8141 LOC: Config.MemPools.limit
8143 Used only with memory_pools on:
8144 memory_pools_limit 50 MB
8146 If set to a non-zero value, Squid will keep at most the specified
8147 limit of allocated (but unused) memory in memory pools. All free()
8148 requests that exceed this limit will be handled by your malloc
8149 library. Squid does not pre-allocate any memory, just safe-keeps
8150 objects that otherwise would be free()d. Thus, it is safe to set
8151 memory_pools_limit to a reasonably high value even if your
8152 configuration will use less memory.
8154 If set to none, Squid will keep all memory it can. That is, there
8155 will be no limit on the total amount of memory used for safe-keeping.
8157 To disable memory allocation optimization, do not set
8158 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
8160 An overhead for maintaining memory pools is not taken into account
8161 when the limit is checked. This overhead is close to four bytes per
8162 object kept. However, pools may actually _save_ memory because of
8163 reduced memory thrashing in your malloc library.
8167 COMMENT: on|off|transparent|truncate|delete
8170 LOC: opt_forwarded_for
8172 If set to "on", Squid will append your client's IP address
8173 in the HTTP requests it forwards. By default it looks like:
8175 X-Forwarded-For: 192.1.2.3
8177 If set to "off", it will appear as
8179 X-Forwarded-For: unknown
8181 If set to "transparent", Squid will not alter the
8182 X-Forwarded-For header in any way.
8184 If set to "delete", Squid will delete the entire
8185 X-Forwarded-For header.
8187 If set to "truncate", Squid will remove all existing
8188 X-Forwarded-For entries, and place the client IP as the sole entry.
8191 NAME: cachemgr_passwd
8192 TYPE: cachemgrpasswd
8194 LOC: Config.passwd_list
8196 Specify passwords for cachemgr operations.
8198 Usage: cachemgr_passwd password action action ...
8200 Some valid actions are (see cache manager menu for a full list):
8240 * Indicates actions which will not be performed without a
8241 valid password, others can be performed if not listed here.
8243 To disable an action, set the password to "disable".
8244 To allow performing an action without a password, set the
8247 Use the keyword "all" to set the same password for all actions.
8250 cachemgr_passwd secret shutdown
8251 cachemgr_passwd lesssssssecret info stats/objects
8252 cachemgr_passwd disable all
8259 LOC: Config.onoff.client_db
8261 If you want to disable collecting per-client statistics,
8262 turn off client_db here.
8265 NAME: refresh_all_ims
8269 LOC: Config.onoff.refresh_all_ims
8271 When you enable this option, squid will always check
8272 the origin server for an update when a client sends an
8273 If-Modified-Since request. Many browsers use IMS
8274 requests when the user requests a reload, and this
8275 ensures those clients receive the latest version.
8277 By default (off), squid may return a Not Modified response
8278 based on the age of the cached version.
8281 NAME: reload_into_ims
8282 IFDEF: USE_HTTP_VIOLATIONS
8286 LOC: Config.onoff.reload_into_ims
8288 When you enable this option, client no-cache or ``reload''
8289 requests will be changed to If-Modified-Since requests.
8290 Doing this VIOLATES the HTTP standard. Enabling this
8291 feature could make you liable for problems which it
8294 see also refresh_pattern for a more selective approach.
8297 NAME: connect_retries
8299 LOC: Config.connect_retries
8302 This sets the maximum number of connection attempts made for each
8303 TCP connection. The connect_retries attempts must all still
8304 complete within the connection timeout period.
8306 The default is not to re-try if the first connection attempt fails.
8307 The (not recommended) maximum is 10 tries.
8309 A warning message will be generated if it is set to a too-high
8310 value and the configured value will be over-ridden.
8312 Note: These re-tries are in addition to forward_max_tries
8313 which limit how many different addresses may be tried to find
8317 NAME: retry_on_error
8319 LOC: Config.retry.onerror
8322 If set to ON Squid will automatically retry requests when
8323 receiving an error response with status 403 (Forbidden),
8324 500 (Internal Error), 501 or 503 (Service not available).
8325 Status 502 and 504 (Gateway errors) are always retried.
8327 This is mainly useful if you are in a complex cache hierarchy to
8328 work around access control errors.
8330 NOTE: This retry will attempt to find another working destination.
8331 Which is different from the server which just failed.
8334 NAME: as_whois_server
8336 LOC: Config.as_whois_server
8337 DEFAULT: whois.ra.net
8339 WHOIS server to query for AS numbers. NOTE: AS numbers are
8340 queried only when Squid starts up, not for every request.
8345 LOC: Config.onoff.offline
8348 Enable this option and Squid will never try to validate cached
8352 NAME: uri_whitespace
8353 TYPE: uri_whitespace
8354 LOC: Config.uri_whitespace
8357 What to do with requests that have whitespace characters in the
8360 strip: The whitespace characters are stripped out of the URL.
8361 This is the behavior recommended by RFC2396.
8362 deny: The request is denied. The user receives an "Invalid
8364 allow: The request is allowed and the URI is not changed. The
8365 whitespace characters remain in the URI. Note the
8366 whitespace is passed to redirector processes if they
8368 encode: The request is allowed and the whitespace characters are
8369 encoded according to RFC1738. This could be considered
8370 a violation of the HTTP/1.1
8371 RFC because proxies are not allowed to rewrite URI's.
8372 chop: The request is allowed and the URI is chopped at the
8373 first whitespace. This might also be considered a
8379 LOC: Config.chroot_dir
8382 Specifies a directory where Squid should do a chroot() while
8383 initializing. This also causes Squid to fully drop root
8384 privileges after initializing. This means, for example, if you
8385 use a HTTP port less than 1024 and try to reconfigure, you may
8386 get an error saying that Squid can not open the port.
8389 NAME: balance_on_multiple_ip
8391 LOC: Config.onoff.balance_on_multiple_ip
8394 Modern IP resolvers in squid sort lookup results by preferred access.
8395 By default squid will use these IP in order and only rotates to
8396 the next listed when the most preffered fails.
8398 Some load balancing servers based on round robin DNS have been
8399 found not to preserve user session state across requests
8400 to different IP addresses.
8402 Enabling this directive Squid rotates IP's per request.
8405 NAME: pipeline_prefetch
8407 LOC: Config.onoff.pipeline_prefetch
8410 To boost the performance of pipelined requests to closer
8411 match that of a non-proxied environment Squid can try to fetch
8412 up to two requests in parallel from a pipeline.
8414 Defaults to off for bandwidth management and access logging
8417 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
8420 NAME: high_response_time_warning
8423 LOC: Config.warnings.high_rptm
8426 If the one-minute median response time exceeds this value,
8427 Squid prints a WARNING with debug level 0 to get the
8428 administrators attention. The value is in milliseconds.
8431 NAME: high_page_fault_warning
8433 LOC: Config.warnings.high_pf
8436 If the one-minute average page fault rate exceeds this
8437 value, Squid prints a WARNING with debug level 0 to get
8438 the administrators attention. The value is in page faults
8442 NAME: high_memory_warning
8444 LOC: Config.warnings.high_memory
8447 If the memory usage (as determined by mallinfo) exceeds
8448 this amount, Squid prints a WARNING with debug level 0 to get
8449 the administrators attention.
8452 NAME: sleep_after_fork
8453 COMMENT: (microseconds)
8455 LOC: Config.sleep_after_fork
8458 When this is set to a non-zero value, the main Squid process
8459 sleeps the specified number of microseconds after a fork()
8460 system call. This sleep may help the situation where your
8461 system reports fork() failures due to lack of (virtual)
8462 memory. Note, however, if you have a lot of child
8463 processes, these sleep delays will add up and your
8464 Squid will not service requests for some amount of time
8465 until all the child processes have been started.
8466 On Windows value less then 1000 (1 milliseconds) are
8470 NAME: windows_ipaddrchangemonitor
8471 IFDEF: _SQUID_WINDOWS_
8475 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
8477 On Windows Squid by default will monitor IP address changes and will
8478 reconfigure itself after any detected event. This is very useful for
8479 proxies connected to internet with dial-up interfaces.
8480 In some cases (a Proxy server acting as VPN gateway is one) it could be
8481 desiderable to disable this behaviour setting this to 'off'.
8482 Note: after changing this, Squid service must be restarted.
8487 IFDEF: USE_SQUID_EUI
8489 LOC: Eui::TheConfig.euiLookup
8491 Whether to lookup the EUI or MAC address of a connected client.
8494 NAME: max_filedescriptors max_filedesc
8497 LOC: Config.max_filedescriptors
8499 The maximum number of filedescriptors supported.
8501 The default "0" means Squid inherits the current ulimit setting.
8503 Note: Changing this requires a restart of Squid. Also
8504 not all comm loops supports large values.
8512 Number of main Squid processes or "workers" to fork and maintain.
8513 0: "no daemon" mode, like running "squid -N ..."
8514 1: "no SMP" mode, start one main Squid process daemon (default)
8515 N: start N main Squid process daemons (i.e., SMP mode)
8517 In SMP mode, each worker does nearly all what a single Squid daemon
8518 does (e.g., listen on http_port and forward HTTP requests).
8521 NAME: cpu_affinity_map
8522 TYPE: CpuAffinityMap
8523 LOC: Config.cpuAffinityMap
8526 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
8528 Sets 1:1 mapping between Squid processes and CPU cores. For example,
8530 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
8532 affects processes 1 through 4 only and places them on the first
8533 four even cores, starting with core #1.
8535 CPU cores are numbered starting from 1. Requires support for
8536 sched_getaffinity(2) and sched_setaffinity(2) system calls.
8538 Multiple cpu_affinity_map options are merged.
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