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 4096 KB 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 Objects larger than this size will NOT be saved on disk. The
3401 value is specified in kilobytes, and the default is 4MB. If
3402 you wish to get a high BYTES hit ratio, you should probably
3403 increase this (one 32 MB object hit counts for 3200 10KB
3404 hits). If you wish to increase speed more than your want to
3405 save bandwidth you should leave this low.
3407 NOTE: if using the LFUDA replacement policy you should increase
3408 this value to maximize the byte hit rate improvement of LFUDA!
3409 See replacement_policy below for a discussion of this policy.
3412 NAME: cache_swap_low
3413 COMMENT: (percent, 0-100)
3416 LOC: Config.Swap.lowWaterMark
3419 NAME: cache_swap_high
3420 COMMENT: (percent, 0-100)
3423 LOC: Config.Swap.highWaterMark
3426 The low- and high-water marks for cache object replacement.
3427 Replacement begins when the swap (disk) usage is above the
3428 low-water mark and attempts to maintain utilization near the
3429 low-water mark. As swap utilization gets close to high-water
3430 mark object eviction becomes more aggressive. If utilization is
3431 close to the low-water mark less replacement is done each time.
3433 Defaults are 90% and 95%. If you have a large cache, 5% could be
3434 hundreds of MB. If this is the case you may wish to set these
3435 numbers closer together.
3440 -----------------------------------------------------------------------------
3450 logformat <name> <format specification>
3452 Defines an access log format.
3454 The <format specification> is a string with embedded % format codes
3456 % format codes all follow the same basic structure where all but
3457 the formatcode is optional. Output strings are automatically escaped
3458 as required according to their context and the output format
3459 modifiers are usually not needed, but can be specified if an explicit
3460 output format is desired.
3462 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3464 " output in quoted string format
3465 [ output in squid text log format as used by log_mime_hdrs
3466 # output in URL quoted format
3471 width minimum and/or maximum field width:
3472 [width_min][.width_max]
3473 When minimum starts with 0, the field is zero-padded.
3474 String values exceeding maximum width are truncated.
3476 {arg} argument such as header name etc
3480 % a literal % character
3481 sn Unique sequence number per log line entry
3482 err_code The ID of an error response served by Squid or
3483 a similar internal error identifier.
3484 err_detail Additional err_code-dependent error information.
3485 note The meta header specified by the argument. Also
3486 logs the adaptation meta headers set by the
3487 adaptation_meta configuration parameter.
3488 If no argument given all meta headers logged.
3490 Connection related format codes:
3492 >a Client source IP address
3494 >p Client source port
3495 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3496 >la Local IP address the client connected to
3497 >lp Local port number the client connected to
3499 la Local listening IP address the client connection was connected to.
3500 lp Local listening port number the client connection was connected to.
3502 <a Server IP address of the last server or peer connection
3503 <A Server FQDN or peer name
3504 <p Server port number of the last server or peer connection
3505 <la Local IP address of the last server or peer connection
3506 <lp Local port number of the last server or peer connection
3508 Time related format codes:
3510 ts Seconds since epoch
3511 tu subsecond time (milliseconds)
3512 tl Local time. Optional strftime format argument
3513 default %d/%b/%Y:%H:%M:%S %z
3514 tg GMT time. Optional strftime format argument
3515 default %d/%b/%Y:%H:%M:%S %z
3516 tr Response time (milliseconds)
3517 dt Total time spent making DNS lookups (milliseconds)
3519 Access Control related format codes:
3521 et Tag returned by external acl
3522 ea Log string returned by external acl
3523 un User name (any available)
3524 ul User name from authentication
3525 ue User name from external acl helper
3526 ui User name from ident
3527 us User name from SSL
3529 HTTP related format codes:
3531 [http::]>h Original request header. Optional header name argument
3532 on the format header[:[separator]element]
3533 [http::]>ha The HTTP request headers after adaptation and redirection.
3534 Optional header name argument as for >h
3535 [http::]<h Reply header. Optional header name argument
3537 [http::]>Hs HTTP status code sent to the client
3538 [http::]<Hs HTTP status code received from the next hop
3539 [http::]<bs Number of HTTP-equivalent message body bytes
3540 received from the next hop, excluding chunked
3541 transfer encoding and control messages.
3542 Generated FTP/Gopher listings are treated as
3544 [http::]mt MIME content type
3545 [http::]rm Request method (GET/POST etc)
3546 [http::]>rm Request method from client
3547 [http::]<rm Request method sent to server or peer
3548 [http::]ru Request URL from client (historic, filtered for logging)
3549 [http::]>ru Request URL from client
3550 [http::]<ru Request URL sent to server or peer
3551 [http::]rp Request URL-Path excluding hostname
3552 [http::]>rp Request URL-Path excluding hostname from client
3553 [http::]<rp Request URL-Path excluding hostname sento to server or peer
3554 [http::]rv Request protocol version
3555 [http::]>rv Request protocol version from client
3556 [http::]<rv Request protocol version sent to server or peer
3557 [http::]<st Sent reply size including HTTP headers
3558 [http::]>st Received request size including HTTP headers. In the
3559 case of chunked requests the chunked encoding metadata
3561 [http::]>sh Received HTTP request headers size
3562 [http::]<sh Sent HTTP reply headers size
3563 [http::]st Request+Reply size including HTTP headers
3564 [http::]<sH Reply high offset sent
3565 [http::]<sS Upstream object size
3566 [http::]<pt Peer response time in milliseconds. The timer starts
3567 when the last request byte is sent to the next hop
3568 and stops when the last response byte is received.
3569 [http::]<tt Total server-side time in milliseconds. The timer
3570 starts with the first connect request (or write I/O)
3571 sent to the first selected peer. The timer stops
3572 with the last I/O with the last peer.
3574 Squid handling related format codes:
3576 Ss Squid request status (TCP_MISS etc)
3577 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3579 SSL-related format codes:
3581 ssl::bump_mode SslBump decision for the transaction:
3583 For CONNECT requests that initiated bumping of
3584 a connection and for any request received on
3585 an already bumped connection, Squid logs the
3586 corresponding SslBump mode ("server-first" or
3587 "client-first"). See the ssl_bump option for
3588 more information about these modes.
3590 A "none" token is logged for requests that
3591 triggered "ssl_bump" ACL evaluation matching
3592 either a "none" rule or no rules at all.
3594 In all other cases, a single dash ("-") is
3597 If ICAP is enabled, the following code becomes available (as
3598 well as ICAP log codes documented with the icap_log option):
3600 icap::tt Total ICAP processing time for the HTTP
3601 transaction. The timer ticks when ICAP
3602 ACLs are checked and when ICAP
3603 transaction is in progress.
3605 If adaptation is enabled the following three codes become available:
3607 adapt::<last_h The header of the last ICAP response or
3608 meta-information from the last eCAP
3609 transaction related to the HTTP transaction.
3610 Like <h, accepts an optional header name
3613 adapt::sum_trs Summed adaptation transaction response
3614 times recorded as a comma-separated list in
3615 the order of transaction start time. Each time
3616 value is recorded as an integer number,
3617 representing response time of one or more
3618 adaptation (ICAP or eCAP) transaction in
3619 milliseconds. When a failed transaction is
3620 being retried or repeated, its time is not
3621 logged individually but added to the
3622 replacement (next) transaction. See also:
3625 adapt::all_trs All adaptation transaction response times.
3626 Same as adaptation_strs but response times of
3627 individual transactions are never added
3628 together. Instead, all transaction response
3629 times are recorded individually.
3631 You can prefix adapt::*_trs format codes with adaptation
3632 service name in curly braces to record response time(s) specific
3633 to that service. For example: %{my_service}adapt::sum_trs
3635 If SSL is enabled, the following formating codes become available:
3637 %ssl::>cert_subject The Subject field of the received client
3638 SSL certificate or a dash ('-') if Squid has
3639 received an invalid/malformed certificate or
3640 no certificate at all. Consider encoding the
3641 logged value because Subject often has spaces.
3643 %ssl::>cert_issuer The Issuer field of the received client
3644 SSL certificate or a dash ('-') if Squid has
3645 received an invalid/malformed certificate or
3646 no certificate at all. Consider encoding the
3647 logged value because Issuer often has spaces.
3649 The default formats available (which do not need re-defining) are:
3651 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3652 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3653 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3654 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3655 logformat useragent %>a [%tl] "%{User-Agent}>h"
3657 NOTE: When the log_mime_hdrs directive is set to ON.
3658 The squid, common and combined formats have a safely encoded copy
3659 of the mime headers appended to each line within a pair of brackets.
3661 NOTE: The common and combined formats are not quite true to the Apache definition.
3662 The logs from Squid contain an extra status and hierarchy code appended.
3666 NAME: access_log cache_access_log
3668 LOC: Config.Log.accesslogs
3669 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3671 These files log client request activities. Has a line every HTTP or
3672 ICP request. The format is:
3673 access_log <module>:<place> [<logformat name> [acl acl ...]]
3674 access_log none [acl acl ...]]
3676 Will log to the specified module:place using the specified format (which
3677 must be defined in a logformat directive) those entries which match
3678 ALL the acl's specified (which must be defined in acl clauses).
3679 If no acl is specified, all requests will be logged to this destination.
3681 ===== Modules Currently available =====
3683 none Do not log any requests matching these ACL.
3684 Do not specify Place or logformat name.
3686 stdio Write each log line to disk immediately at the completion of
3688 Place: the filename and path to be written.
3690 daemon Very similar to stdio. But instead of writing to disk the log
3691 line is passed to a daemon helper for asychronous handling instead.
3692 Place: varies depending on the daemon.
3694 log_file_daemon Place: the file name and path to be written.
3696 syslog To log each request via syslog facility.
3697 Place: The syslog facility and priority level for these entries.
3698 Place Format: facility.priority
3700 where facility could be any of:
3701 authpriv, daemon, local0 ... local7 or user.
3703 And priority could be any of:
3704 err, warning, notice, info, debug.
3706 udp To send each log line as text data to a UDP receiver.
3707 Place: The destination host name or IP and port.
3708 Place Format: //host:port
3710 tcp To send each log line as text data to a TCP receiver.
3711 Place: The destination host name or IP and port.
3712 Place Format: //host:port
3715 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3721 LOC: Config.Log.icaplogs
3724 ICAP log files record ICAP transaction summaries, one line per
3727 The icap_log option format is:
3728 icap_log <filepath> [<logformat name> [acl acl ...]]
3729 icap_log none [acl acl ...]]
3731 Please see access_log option documentation for details. The two
3732 kinds of logs share the overall configuration approach and many
3735 ICAP processing of a single HTTP message or transaction may
3736 require multiple ICAP transactions. In such cases, multiple
3737 ICAP transaction log lines will correspond to a single access
3740 ICAP log uses logformat codes that make sense for an ICAP
3741 transaction. Header-related codes are applied to the HTTP header
3742 embedded in an ICAP server response, with the following caveats:
3743 For REQMOD, there is no HTTP response header unless the ICAP
3744 server performed request satisfaction. For RESPMOD, the HTTP
3745 request header is the header sent to the ICAP server. For
3746 OPTIONS, there are no HTTP headers.
3748 The following format codes are also available for ICAP logs:
3750 icap::<A ICAP server IP address. Similar to <A.
3752 icap::<service_name ICAP service name from the icap_service
3753 option in Squid configuration file.
3755 icap::ru ICAP Request-URI. Similar to ru.
3757 icap::rm ICAP request method (REQMOD, RESPMOD, or
3758 OPTIONS). Similar to existing rm.
3760 icap::>st Bytes sent to the ICAP server (TCP payload
3761 only; i.e., what Squid writes to the socket).
3763 icap::<st Bytes received from the ICAP server (TCP
3764 payload only; i.e., what Squid reads from
3767 icap::<bs Number of message body bytes received from the
3768 ICAP server. ICAP message body, if any, usually
3769 includes encapsulated HTTP message headers and
3770 possibly encapsulated HTTP message body. The
3771 HTTP body part is dechunked before its size is
3774 icap::tr Transaction response time (in
3775 milliseconds). The timer starts when
3776 the ICAP transaction is created and
3777 stops when the transaction is completed.
3780 icap::tio Transaction I/O time (in milliseconds). The
3781 timer starts when the first ICAP request
3782 byte is scheduled for sending. The timers
3783 stops when the last byte of the ICAP response
3786 icap::to Transaction outcome: ICAP_ERR* for all
3787 transaction errors, ICAP_OPT for OPTION
3788 transactions, ICAP_ECHO for 204
3789 responses, ICAP_MOD for message
3790 modification, and ICAP_SAT for request
3791 satisfaction. Similar to Ss.
3793 icap::Hs ICAP response status code. Similar to Hs.
3795 icap::>h ICAP request header(s). Similar to >h.
3797 icap::<h ICAP response header(s). Similar to <h.
3799 The default ICAP log format, which can be used without an explicit
3800 definition, is called icap_squid:
3802 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3804 See also: logformat, log_icap, and %adapt::<last_h
3807 NAME: logfile_daemon
3809 DEFAULT: @DEFAULT_LOGFILED@
3810 LOC: Log::TheConfig.logfile_daemon
3812 Specify the path to the logfile-writing daemon. This daemon is
3813 used to write the access and store logs, if configured.
3815 Squid sends a number of commands to the log daemon:
3816 L<data>\n - logfile data
3821 r<n>\n - set rotate count to <n>
3822 b<n>\n - 1 = buffer output, 0 = don't buffer output
3824 No responses is expected.
3829 LOC: Config.accessList.log
3831 COMMENT: allow|deny acl acl...
3833 This options allows you to control which requests gets logged
3834 to access.log (see access_log directive). Requests denied for
3835 logging will also not be accounted for in performance counters.
3837 This clause only supports fast acl types.
3838 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3844 LOC: Config.accessList.icap
3847 This options allows you to control which requests get logged
3848 to icap.log. See the icap_log directive for ICAP log details.
3851 NAME: cache_store_log
3854 LOC: Config.Log.store
3856 Logs the activities of the storage manager. Shows which
3857 objects are ejected from the cache, and which objects are
3858 saved and for how long.
3859 There are not really utilities to analyze this data, so you can safely
3860 disable it (the default).
3862 Store log uses modular logging outputs. See access_log for the list
3863 of modules supported.
3866 cache_store_log stdio:@DEFAULT_STORE_LOG@
3867 cache_store_log daemon:@DEFAULT_STORE_LOG@
3870 NAME: cache_swap_state cache_swap_log
3872 LOC: Config.Log.swap
3875 Location for the cache "swap.state" file. This index file holds
3876 the metadata of objects saved on disk. It is used to rebuild
3877 the cache during startup. Normally this file resides in each
3878 'cache_dir' directory, but you may specify an alternate
3879 pathname here. Note you must give a full filename, not just
3880 a directory. Since this is the index for the whole object
3881 list you CANNOT periodically rotate it!
3883 If %s can be used in the file name it will be replaced with a
3884 a representation of the cache_dir name where each / is replaced
3885 with '.'. This is needed to allow adding/removing cache_dir
3886 lines when cache_swap_log is being used.
3888 If have more than one 'cache_dir', and %s is not used in the name
3889 these swap logs will have names such as:
3895 The numbered extension (which is added automatically)
3896 corresponds to the order of the 'cache_dir' lines in this
3897 configuration file. If you change the order of the 'cache_dir'
3898 lines in this file, these index files will NOT correspond to
3899 the correct 'cache_dir' entry (unless you manually rename
3900 them). We recommend you do NOT use this option. It is
3901 better to keep these index files in each 'cache_dir' directory.
3904 NAME: logfile_rotate
3907 LOC: Config.Log.rotateNumber
3909 Specifies the number of logfile rotations to make when you
3910 type 'squid -k rotate'. The default is 10, which will rotate
3911 with extensions 0 through 9. Setting logfile_rotate to 0 will
3912 disable the file name rotation, but the logfiles are still closed
3913 and re-opened. This will enable you to rename the logfiles
3914 yourself just before sending the rotate signal.
3916 Note, the 'squid -k rotate' command normally sends a USR1
3917 signal to the running squid process. In certain situations
3918 (e.g. on Linux with Async I/O), USR1 is used for other
3919 purposes, so -k rotate uses another signal. It is best to get
3920 in the habit of using 'squid -k rotate' instead of 'kill -USR1
3923 Note, from Squid-3.1 this option has no effect on the cache.log,
3924 that log can be rotated separately by using debug_options
3927 NAME: emulate_httpd_log
3930 Replace this with an access_log directive using the format 'common' or 'combined'.
3933 NAME: log_ip_on_direct
3936 Remove this option from your config. To log server or peer names use %<A in the log format.
3941 DEFAULT: @DEFAULT_MIME_TABLE@
3942 LOC: Config.mimeTablePathname
3944 Pathname to Squid's MIME table. You shouldn't need to change
3945 this, but the default file contains examples and formatting
3946 information if you do.
3952 LOC: Config.onoff.log_mime_hdrs
3955 The Cache can record both the request and the response MIME
3956 headers for each HTTP transaction. The headers are encoded
3957 safely and will appear as two bracketed fields at the end of
3958 the access log (for either the native or httpd-emulated log
3959 formats). To enable this logging set log_mime_hdrs to 'on'.
3965 Replace this with an access_log directive using the format 'useragent'.
3968 NAME: referer_log referrer_log
3971 Replace this with an access_log directive using the format 'referrer'.
3976 DEFAULT: @DEFAULT_PID_FILE@
3977 LOC: Config.pidFilename
3979 A filename to write the process-id to. To disable, enter "none".
3985 Remove this option from your config. To log FQDN use %>A in the log format.
3988 NAME: client_netmask
3990 LOC: Config.Addrs.client_netmask
3993 A netmask for client addresses in logfiles and cachemgr output.
3994 Change this to protect the privacy of your cache clients.
3995 A netmask of 255.255.255.0 will log all IP's in that range with
3996 the last digit set to '0'.
4002 Use a regular access.log with ACL limiting it to MISS events.
4005 NAME: strip_query_terms
4007 LOC: Config.onoff.strip_query_terms
4010 By default, Squid strips query terms from requested URLs before
4011 logging. This protects your user's privacy.
4018 LOC: Config.onoff.buffered_logs
4020 cache.log log file is written with stdio functions, and as such
4021 it can be buffered or unbuffered. By default it will be unbuffered.
4022 Buffering it can speed up the writing slightly (though you are
4023 unlikely to need to worry unless you run with tons of debugging
4024 enabled in which case performance will suffer badly anyway..).
4027 NAME: netdb_filename
4029 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4030 LOC: Config.netdbFilename
4033 A filename where Squid stores it's netdb state between restarts.
4034 To disable, enter "none".
4038 OPTIONS FOR TROUBLESHOOTING
4039 -----------------------------------------------------------------------------
4044 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4045 LOC: Debug::cache_log
4047 Cache logging file. This is where general information about
4048 your cache's behavior goes. You can increase the amount of data
4049 logged to this file and how often its rotated with "debug_options"
4055 LOC: Debug::debugOptions
4057 Logging options are set as section,level where each source file
4058 is assigned a unique section. Lower levels result in less
4059 output, Full debugging (level 9) can result in a very large
4060 log file, so be careful.
4062 The magic word "ALL" sets debugging levels for all sections.
4063 We recommend normally running with "ALL,1".
4065 The rotate=N option can be used to keep more or less of these logs
4066 than would otherwise be kept by logfile_rotate.
4067 For most uses a single log should be enough to monitor current
4068 events affecting Squid.
4073 LOC: Config.coredump_dir
4074 DEFAULT_IF_NONE: none
4076 By default Squid leaves core files in the directory from where
4077 it was started. If you set 'coredump_dir' to a directory
4078 that exists, Squid will chdir() to that directory at startup
4079 and coredump files will be left there.
4083 # Leave coredumps in the first cache dir
4084 coredump_dir @DEFAULT_SWAP_DIR@
4090 OPTIONS FOR FTP GATEWAYING
4091 -----------------------------------------------------------------------------
4097 LOC: Config.Ftp.anon_user
4099 If you want the anonymous login password to be more informative
4100 (and enable the use of picky ftp servers), set this to something
4101 reasonable for your domain, like wwwuser@somewhere.net
4103 The reason why this is domainless by default is the
4104 request can be made on the behalf of a user in any domain,
4105 depending on how the cache is used.
4106 Some ftp server also validate the email address is valid
4107 (for example perl.com).
4113 LOC: Config.Ftp.passive
4115 If your firewall does not allow Squid to use passive
4116 connections, turn off this option.
4118 Use of ftp_epsv_all option requires this to be ON.
4124 LOC: Config.Ftp.epsv_all
4126 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4128 NATs may be able to put the connection on a "fast path" through the
4129 translator, as the EPRT command will never be used and therefore,
4130 translation of the data portion of the segments will never be needed.
4132 When a client only expects to do two-way FTP transfers this may be
4134 If squid finds that it must do a three-way FTP transfer after issuing
4135 an EPSV ALL command, the FTP session will fail.
4137 If you have any doubts about this option do not use it.
4138 Squid will nicely attempt all other connection methods.
4140 Requires ftp_passive to be ON (default) for any effect.
4146 LOC: Config.Ftp.epsv
4148 FTP Protocol extensions permit the use of a special "EPSV" command.
4150 NATs may be able to put the connection on a "fast path" through the
4151 translator using EPSV, as the EPRT command will never be used
4152 and therefore, translation of the data portion of the segments
4153 will never be needed.
4155 Turning this OFF will prevent EPSV being attempted.
4156 WARNING: Doing so will convert Squid back to the old behavior with all
4157 the related problems with external NAT devices/layers.
4159 Requires ftp_passive to be ON (default) for any effect.
4165 LOC: Config.Ftp.eprt
4167 FTP Protocol extensions permit the use of a special "EPRT" command.
4169 This extension provides a protocol neutral alternative to the
4170 IPv4-only PORT command. When supported it enables active FTP data
4171 channels over IPv6 and efficient NAT handling.
4173 Turning this OFF will prevent EPRT being attempted and will skip
4174 straight to using PORT for IPv4 servers.
4176 Some devices are known to not handle this extension correctly and
4177 may result in crashes. Devices which suport EPRT enough to fail
4178 cleanly will result in Squid attempting PORT anyway. This directive
4179 should only be disabled when EPRT results in device failures.
4181 WARNING: Doing so will convert Squid back to the old behavior with all
4182 the related problems with external NAT devices/layers and IPv4-only FTP.
4185 NAME: ftp_sanitycheck
4188 LOC: Config.Ftp.sanitycheck
4190 For security and data integrity reasons Squid by default performs
4191 sanity checks of the addresses of FTP data connections ensure the
4192 data connection is to the requested server. If you need to allow
4193 FTP connections to servers using another IP address for the data
4194 connection turn this off.
4197 NAME: ftp_telnet_protocol
4200 LOC: Config.Ftp.telnet
4202 The FTP protocol is officially defined to use the telnet protocol
4203 as transport channel for the control connection. However, many
4204 implementations are broken and does not respect this aspect of
4207 If you have trouble accessing files with ASCII code 255 in the
4208 path or similar problems involving this ASCII code you can
4209 try setting this directive to off. If that helps, report to the
4210 operator of the FTP server in question that their FTP server
4211 is broken and does not follow the FTP standard.
4215 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4216 -----------------------------------------------------------------------------
4221 DEFAULT: @DEFAULT_DISKD@
4222 LOC: Config.Program.diskd
4224 Specify the location of the diskd executable.
4225 Note this is only useful if you have compiled in
4226 diskd as one of the store io modules.
4229 NAME: unlinkd_program
4232 DEFAULT: @DEFAULT_UNLINKD@
4233 LOC: Config.Program.unlinkd
4235 Specify the location of the executable for file deletion process.
4238 NAME: pinger_program
4240 DEFAULT: @DEFAULT_PINGER@
4241 LOC: Config.pinger.program
4244 Specify the location of the executable for the pinger process.
4250 LOC: Config.pinger.enable
4253 Control whether the pinger is active at run-time.
4254 Enables turning ICMP pinger on and off with a simple
4255 squid -k reconfigure.
4260 OPTIONS FOR URL REWRITING
4261 -----------------------------------------------------------------------------
4264 NAME: url_rewrite_program redirect_program
4266 LOC: Config.Program.redirect
4269 Specify the location of the executable URL rewriter to use.
4270 Since they can perform almost any function there isn't one included.
4272 For each requested URL, the rewriter will receive on line with the format
4274 [channel-ID <SP>] URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kv-pairs]<NL>
4277 After processing the request the helper must reply using the following format:
4279 [channel-ID <SP>] result [<SP> kv-pairs]
4281 The result code can be:
4283 OK status=30N url="..."
4284 Redirect the URL to the one supplied in 'url='.
4285 'status=' is optional and contains the status code to send
4286 the client in Squids HTTP response. It must be one of the
4287 HTTP redirect status codes: 301, 302, 303, 307, 308.
4288 When no status is given Squid will use 302.
4290 OK rewrite-url="..."
4291 Rewrite the URL to the one supplied in 'rewrite-url='.
4292 The new URL is fetched directly by Squid and returned to
4293 the client as the response to its request.
4296 Do not change the URL.
4299 An internal error occurred in the helper, preventing
4300 a result being identified.
4303 In the future, the interface protocol will be extended with
4304 key=value pairs ("kv-pairs" shown above). Helper programs
4305 should be prepared to receive and possibly ignore additional
4306 whitespace-separated tokens on each input line.
4308 When using the concurrency= option the protocol is changed by
4309 introducing a query channel tag in front of the request/response.
4310 The query channel tag is a number between 0 and concurrency-1.
4311 This value must be echoed back unchanged to Squid as the first part
4312 of the response relating to its request.
4314 WARNING: URL re-writing ability should be avoided whenever possible.
4315 Use the URL redirect form of response instead.
4317 Re-write creates a difference in the state held by the client
4318 and server. Possibly causing confusion when the server response
4319 contains snippets of its view state. Embeded URLs, response
4320 and content Location headers, etc. are not re-written by this
4323 By default, a URL rewriter is not used.
4326 NAME: url_rewrite_children redirect_children
4327 TYPE: HelperChildConfig
4328 DEFAULT: 20 startup=0 idle=1 concurrency=0
4329 LOC: Config.redirectChildren
4331 The maximum number of redirector processes to spawn. If you limit
4332 it too few Squid will have to wait for them to process a backlog of
4333 URLs, slowing it down. If you allow too many they will use RAM
4334 and other system resources noticably.
4336 The startup= and idle= options allow some measure of skew in your
4341 Sets a minimum of how many processes are to be spawned when Squid
4342 starts or reconfigures. When set to zero the first request will
4343 cause spawning of the first child process to handle it.
4345 Starting too few will cause an initial slowdown in traffic as Squid
4346 attempts to simultaneously spawn enough processes to cope.
4350 Sets a minimum of how many processes Squid is to try and keep available
4351 at all times. When traffic begins to rise above what the existing
4352 processes can handle this many more will be spawned up to the maximum
4353 configured. A minimum setting of 1 is required.
4357 The number of requests each redirector helper can handle in
4358 parallel. Defaults to 0 which indicates the redirector
4359 is a old-style single threaded redirector.
4361 When this directive is set to a value >= 1 then the protocol
4362 used to communicate with the helper is modified to include
4363 an ID in front of the request/response. The ID from the request
4364 must be echoed back with the response to that request.
4367 NAME: url_rewrite_host_header redirect_rewrites_host_header
4370 LOC: Config.onoff.redir_rewrites_host
4372 To preserve same-origin security policies in browsers and
4373 prevent Host: header forgery by redirectors Squid rewrites
4374 any Host: header in redirected requests.
4376 If you are running an accelerator this may not be a wanted
4377 effect of a redirector. This directive enables you disable
4378 Host: alteration in reverse-proxy traffic.
4380 WARNING: Entries are cached on the result of the URL rewriting
4381 process, so be careful if you have domain-virtual hosts.
4383 WARNING: Squid and other software verifies the URL and Host
4384 are matching, so be careful not to relay through other proxies
4385 or inspecting firewalls with this disabled.
4388 NAME: url_rewrite_access redirector_access
4391 LOC: Config.accessList.redirector
4393 If defined, this access list specifies which requests are
4394 sent to the redirector processes. By default all requests
4397 This clause supports both fast and slow acl types.
4398 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4401 NAME: url_rewrite_bypass redirector_bypass
4403 LOC: Config.onoff.redirector_bypass
4406 When this is 'on', a request will not go through the
4407 redirector if all redirectors are busy. If this is 'off'
4408 and the redirector queue grows too large, Squid will exit
4409 with a FATAL error and ask you to increase the number of
4410 redirectors. You should only enable this if the redirectors
4411 are not critical to your caching system. If you use
4412 redirectors for access control, and you enable this option,
4413 users may have access to pages they should not
4414 be allowed to request.
4418 OPTIONS FOR STORE ID
4419 -----------------------------------------------------------------------------
4422 NAME: store_id_program storeurl_rewrite_program
4424 LOC: Config.Program.store_id
4427 Specify the location of the executable StoreID helper to use.
4428 Since they can perform almost any function there isn't one included.
4430 For each requested URL, the helper will receive one line with the format
4432 [channel-ID <SP>] URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kv-pairs]<NL>
4435 After processing the request the helper must reply using the following format:
4437 [channel-ID <SP>] result [<SP> kv-pairs]
4439 The result code can be:
4442 Use the StoreID supplied in 'store-id='.
4445 The default is to use HTTP request URL as the store ID.
4448 An internal error occured in the helper, preventing
4449 a result being identified.
4452 Helper programs should be prepared to receive and possibly ignore additional
4453 kv-pairs with keys they do not support.
4455 When using the concurrency= option the protocol is changed by
4456 introducing a query channel tag in front of the request/response.
4457 The query channel tag is a number between 0 and concurrency-1.
4458 This value must be echoed back unchanged to Squid as the first part
4459 of the response relating to its request.
4461 NOTE: when using StoreID refresh_pattern will apply to the StoreID
4462 returned from the helper and not the URL.
4464 WARNING: Wrong StoreID value returned by a careless helper may result
4465 in the wrong cached response returned to the user.
4467 By default, a StoreID helper is not used.
4470 NAME: store_id_children storeurl_rewrite_children
4471 TYPE: HelperChildConfig
4472 DEFAULT: 20 startup=0 idle=1 concurrency=0
4473 LOC: Config.storeIdChildren
4475 The maximum number of StoreID helper processes to spawn. If you limit
4476 it too few Squid will have to wait for them to process a backlog of
4477 requests, slowing it down. If you allow too many they will use RAM
4478 and other system resources noticably.
4480 The startup= and idle= options allow some measure of skew in your
4485 Sets a minimum of how many processes are to be spawned when Squid
4486 starts or reconfigures. When set to zero the first request will
4487 cause spawning of the first child process to handle it.
4489 Starting too few will cause an initial slowdown in traffic as Squid
4490 attempts to simultaneously spawn enough processes to cope.
4494 Sets a minimum of how many processes Squid is to try and keep available
4495 at all times. When traffic begins to rise above what the existing
4496 processes can handle this many more will be spawned up to the maximum
4497 configured. A minimum setting of 1 is required.
4501 The number of requests each storeID helper can handle in
4502 parallel. Defaults to 0 which indicates the helper
4503 is a old-style single threaded program.
4505 When this directive is set to a value >= 1 then the protocol
4506 used to communicate with the helper is modified to include
4507 an ID in front of the request/response. The ID from the request
4508 must be echoed back with the response to that request.
4511 NAME: store_id_access storeurl_rewrite_access
4514 LOC: Config.accessList.store_id
4516 If defined, this access list specifies which requests are
4517 sent to the StoreID processes. By default all requests
4520 This clause supports both fast and slow acl types.
4521 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4524 NAME: store_id_bypass storeurl_rewrite_bypass
4526 LOC: Config.onoff.store_id_bypass
4529 When this is 'on', a request will not go through the
4530 helper if all helpers are busy. If this is 'off'
4531 and the helper queue grows too large, Squid will exit
4532 with a FATAL error and ask you to increase the number of
4533 helpers. You should only enable this if the helperss
4534 are not critical to your caching system. If you use
4535 helpers for critical caching components, and you enable this
4536 option, users may not get objects from cache.
4540 OPTIONS FOR TUNING THE CACHE
4541 -----------------------------------------------------------------------------
4544 NAME: cache no_cache
4547 LOC: Config.accessList.noCache
4549 A list of ACL elements which, if matched and denied, cause the request to
4550 not be satisfied from the cache and the reply to not be cached.
4551 In other words, use this to force certain objects to never be cached.
4553 You must use the words 'allow' or 'deny' to indicate whether items
4554 matching the ACL should be allowed or denied into the cache.
4556 Default is to allow all to be cached.
4558 This clause supports both fast and slow acl types.
4559 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4565 LOC: Config.maxStale
4568 This option puts an upper limit on how stale content Squid
4569 will serve from the cache if cache validation fails.
4570 Can be overriden by the refresh_pattern max-stale option.
4573 NAME: refresh_pattern
4574 TYPE: refreshpattern
4578 usage: refresh_pattern [-i] regex min percent max [options]
4580 By default, regular expressions are CASE-SENSITIVE. To make
4581 them case-insensitive, use the -i option.
4583 'Min' is the time (in minutes) an object without an explicit
4584 expiry time should be considered fresh. The recommended
4585 value is 0, any higher values may cause dynamic applications
4586 to be erroneously cached unless the application designer
4587 has taken the appropriate actions.
4589 'Percent' is a percentage of the objects age (time since last
4590 modification age) an object without explicit expiry time
4591 will be considered fresh.
4593 'Max' is an upper limit on how long objects without an explicit
4594 expiry time will be considered fresh.
4596 options: override-expire
4601 ignore-must-revalidate
4608 override-expire enforces min age even if the server
4609 sent an explicit expiry time (e.g., with the
4610 Expires: header or Cache-Control: max-age). Doing this
4611 VIOLATES the HTTP standard. Enabling this feature
4612 could make you liable for problems which it causes.
4614 Note: override-expire does not enforce staleness - it only extends
4615 freshness / min. If the server returns a Expires time which
4616 is longer than your max time, Squid will still consider
4617 the object fresh for that period of time.
4619 override-lastmod enforces min age even on objects
4620 that were modified recently.
4622 reload-into-ims changes client no-cache or ``reload''
4623 to If-Modified-Since requests. Doing this VIOLATES the
4624 HTTP standard. Enabling this feature could make you
4625 liable for problems which it causes.
4627 ignore-reload ignores a client no-cache or ``reload''
4628 header. Doing this VIOLATES the HTTP standard. Enabling
4629 this feature could make you liable for problems which
4632 ignore-no-store ignores any ``Cache-control: no-store''
4633 headers received from a server. Doing this VIOLATES
4634 the HTTP standard. Enabling this feature could make you
4635 liable for problems which it causes.
4637 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
4638 headers received from a server. Doing this VIOLATES
4639 the HTTP standard. Enabling this feature could make you
4640 liable for problems which it causes.
4642 ignore-private ignores any ``Cache-control: private''
4643 headers received from a server. Doing this VIOLATES
4644 the HTTP standard. Enabling this feature could make you
4645 liable for problems which it causes.
4647 ignore-auth caches responses to requests with authorization,
4648 as if the originserver had sent ``Cache-control: public''
4649 in the response header. Doing this VIOLATES the HTTP standard.
4650 Enabling this feature could make you liable for problems which
4653 refresh-ims causes squid to contact the origin server
4654 when a client issues an If-Modified-Since request. This
4655 ensures that the client will receive an updated version
4656 if one is available.
4658 store-stale stores responses even if they don't have explicit
4659 freshness or a validator (i.e., Last-Modified or an ETag)
4660 present, or if they're already stale. By default, Squid will
4661 not cache such responses because they usually can't be
4662 reused. Note that such responses will be stale by default.
4664 max-stale=NN provide a maximum staleness factor. Squid won't
4665 serve objects more stale than this even if it failed to
4666 validate the object. Default: use the max_stale global limit.
4668 Basically a cached object is:
4670 FRESH if expires < now, else STALE
4672 FRESH if lm-factor < percent, else STALE
4676 The refresh_pattern lines are checked in the order listed here.
4677 The first entry which matches is used. If none of the entries
4678 match the default will be used.
4680 Note, you must uncomment all the default lines if you want
4681 to change one. The default setting is only active if none is
4686 # Add any of your own refresh_pattern entries above these.
4687 refresh_pattern ^ftp: 1440 20% 10080
4688 refresh_pattern ^gopher: 1440 0% 1440
4689 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
4690 refresh_pattern . 0 20% 4320
4694 NAME: quick_abort_min
4698 LOC: Config.quickAbort.min
4701 NAME: quick_abort_max
4705 LOC: Config.quickAbort.max
4708 NAME: quick_abort_pct
4712 LOC: Config.quickAbort.pct
4714 The cache by default continues downloading aborted requests
4715 which are almost completed (less than 16 KB remaining). This
4716 may be undesirable on slow (e.g. SLIP) links and/or very busy
4717 caches. Impatient users may tie up file descriptors and
4718 bandwidth by repeatedly requesting and immediately aborting
4721 When the user aborts a request, Squid will check the
4722 quick_abort values to the amount of data transfered until
4725 If the transfer has less than 'quick_abort_min' KB remaining,
4726 it will finish the retrieval.
4728 If the transfer has more than 'quick_abort_max' KB remaining,
4729 it will abort the retrieval.
4731 If more than 'quick_abort_pct' of the transfer has completed,
4732 it will finish the retrieval.
4734 If you do not want any retrieval to continue after the client
4735 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
4738 If you want retrievals to always continue if they are being
4739 cached set 'quick_abort_min' to '-1 KB'.
4742 NAME: read_ahead_gap
4743 COMMENT: buffer-size
4745 LOC: Config.readAheadGap
4748 The amount of data the cache will buffer ahead of what has been
4749 sent to the client when retrieving an object from another server.
4753 IFDEF: USE_HTTP_VIOLATIONS
4756 LOC: Config.negativeTtl
4759 Set the Default Time-to-Live (TTL) for failed requests.
4760 Certain types of failures (such as "connection refused" and
4761 "404 Not Found") are able to be negatively-cached for a short time.
4762 Modern web servers should provide Expires: header, however if they
4763 do not this can provide a minimum TTL.
4764 The default is not to cache errors with unknown expiry details.
4766 Note that this is different from negative caching of DNS lookups.
4768 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4769 this feature could make you liable for problems which it
4773 NAME: positive_dns_ttl
4776 LOC: Config.positiveDnsTtl
4779 Upper limit on how long Squid will cache positive DNS responses.
4780 Default is 6 hours (360 minutes). This directive must be set
4781 larger than negative_dns_ttl.
4784 NAME: negative_dns_ttl
4787 LOC: Config.negativeDnsTtl
4790 Time-to-Live (TTL) for negative caching of failed DNS lookups.
4791 This also sets the lower cache limit on positive lookups.
4792 Minimum value is 1 second, and it is not recommendable to go
4793 much below 10 seconds.
4796 NAME: range_offset_limit
4797 COMMENT: size [acl acl...]
4799 LOC: Config.rangeOffsetLimit
4802 usage: (size) [units] [[!]aclname]
4804 Sets an upper limit on how far (number of bytes) into the file
4805 a Range request may be to cause Squid to prefetch the whole file.
4806 If beyond this limit, Squid forwards the Range request as it is and
4807 the result is NOT cached.
4809 This is to stop a far ahead range request (lets say start at 17MB)
4810 from making Squid fetch the whole object up to that point before
4811 sending anything to the client.
4813 Multiple range_offset_limit lines may be specified, and they will
4814 be searched from top to bottom on each request until a match is found.
4815 The first match found will be used. If no line matches a request, the
4816 default limit of 0 bytes will be used.
4818 'size' is the limit specified as a number of units.
4820 'units' specifies whether to use bytes, KB, MB, etc.
4821 If no units are specified bytes are assumed.
4823 A size of 0 causes Squid to never fetch more than the
4824 client requested. (default)
4826 A size of 'none' causes Squid to always fetch the object from the
4827 beginning so it may cache the result. (2.0 style)
4829 'aclname' is the name of a defined ACL.
4831 NP: Using 'none' as the byte value here will override any quick_abort settings
4832 that may otherwise apply to the range request. The range request will
4833 be fully fetched from start to finish regardless of the client
4834 actions. This affects bandwidth usage.
4837 NAME: minimum_expiry_time
4840 LOC: Config.minimum_expiry_time
4843 The minimum caching time according to (Expires - Date)
4844 Headers Squid honors if the object can't be revalidated
4845 defaults to 60 seconds. In reverse proxy environments it
4846 might be desirable to honor shorter object lifetimes. It
4847 is most likely better to make your server return a
4848 meaningful Last-Modified header however. In ESI environments
4849 where page fragments often have short lifetimes, this will
4850 often be best set to 0.
4853 NAME: store_avg_object_size
4857 LOC: Config.Store.avgObjectSize
4859 Average object size, used to estimate number of objects your
4860 cache can hold. The default is 13 KB.
4863 NAME: store_objects_per_bucket
4866 LOC: Config.Store.objectsPerBucket
4868 Target number of objects per bucket in the store hash table.
4869 Lowering this value increases the total number of buckets and
4870 also the storage maintenance rate. The default is 20.
4875 -----------------------------------------------------------------------------
4878 NAME: request_header_max_size
4882 LOC: Config.maxRequestHeaderSize
4884 This specifies the maximum size for HTTP headers in a request.
4885 Request headers are usually relatively small (about 512 bytes).
4886 Placing a limit on the request header size will catch certain
4887 bugs (for example with persistent connections) and possibly
4888 buffer-overflow or denial-of-service attacks.
4891 NAME: reply_header_max_size
4895 LOC: Config.maxReplyHeaderSize
4897 This specifies the maximum size for HTTP headers in a reply.
4898 Reply headers are usually relatively small (about 512 bytes).
4899 Placing a limit on the reply header size will catch certain
4900 bugs (for example with persistent connections) and possibly
4901 buffer-overflow or denial-of-service attacks.
4904 NAME: request_body_max_size
4908 LOC: Config.maxRequestBodySize
4910 This specifies the maximum size for an HTTP request body.
4911 In other words, the maximum size of a PUT/POST request.
4912 A user who attempts to send a request with a body larger
4913 than this limit receives an "Invalid Request" error message.
4914 If you set this parameter to a zero (the default), there will
4915 be no limit imposed.
4918 NAME: client_request_buffer_max_size
4922 LOC: Config.maxRequestBufferSize
4924 This specifies the maximum buffer size of a client request.
4925 It prevents squid eating too much memory when somebody uploads
4929 NAME: chunked_request_body_max_size
4933 LOC: Config.maxChunkedRequestBodySize
4935 A broken or confused HTTP/1.1 client may send a chunked HTTP
4936 request to Squid. Squid does not have full support for that
4937 feature yet. To cope with such requests, Squid buffers the
4938 entire request and then dechunks request body to create a
4939 plain HTTP/1.0 request with a known content length. The plain
4940 request is then used by the rest of Squid code as usual.
4942 The option value specifies the maximum size of the buffer used
4943 to hold the request before the conversion. If the chunked
4944 request size exceeds the specified limit, the conversion
4945 fails, and the client receives an "unsupported request" error,
4946 as if dechunking was disabled.
4948 Dechunking is enabled by default. To disable conversion of
4949 chunked requests, set the maximum to zero.
4951 Request dechunking feature and this option in particular are a
4952 temporary hack. When chunking requests and responses are fully
4953 supported, there will be no need to buffer a chunked request.
4957 IFDEF: USE_HTTP_VIOLATIONS
4960 LOC: Config.accessList.brokenPosts
4962 A list of ACL elements which, if matched, causes Squid to send
4963 an extra CRLF pair after the body of a PUT/POST request.
4965 Some HTTP servers has broken implementations of PUT/POST,
4966 and rely on an extra CRLF pair sent by some WWW clients.
4968 Quote from RFC2616 section 4.1 on this matter:
4970 Note: certain buggy HTTP/1.0 client implementations generate an
4971 extra CRLF's after a POST request. To restate what is explicitly
4972 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
4973 a request with an extra CRLF.
4975 This clause only supports fast acl types.
4976 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4979 acl buggy_server url_regex ^http://....
4980 broken_posts allow buggy_server
4983 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
4986 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
4988 LOC: Adaptation::Config::use_indirect_client
4990 Controls whether the indirect client IP address (instead of the direct
4991 client IP address) is passed to adaptation services.
4993 See also: follow_x_forwarded_for adaptation_send_client_ip
4997 IFDEF: USE_HTTP_VIOLATIONS
5001 LOC: Config.onoff.via
5003 If set (default), Squid will include a Via header in requests and
5004 replies as required by RFC2616.
5010 LOC: Config.onoff.ie_refresh
5013 Microsoft Internet Explorer up until version 5.5 Service
5014 Pack 1 has an issue with transparent proxies, wherein it
5015 is impossible to force a refresh. Turning this on provides
5016 a partial fix to the problem, by causing all IMS-REFRESH
5017 requests from older IE versions to check the origin server
5018 for fresh content. This reduces hit ratio by some amount
5019 (~10% in my experience), but allows users to actually get
5020 fresh content when they want it. Note because Squid
5021 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5022 of 5.5 is unchanged from old versions of Squid (i.e. a
5023 forced refresh is impossible). Newer versions of IE will,
5024 hopefully, continue to have the new behavior and will be
5025 handled based on that assumption. This option defaults to
5026 the old Squid behavior, which is better for hit ratios but
5027 worse for clients using IE, if they need to be able to
5028 force fresh content.
5031 NAME: vary_ignore_expire
5034 LOC: Config.onoff.vary_ignore_expire
5037 Many HTTP servers supporting Vary gives such objects
5038 immediate expiry time with no cache-control header
5039 when requested by a HTTP/1.0 client. This option
5040 enables Squid to ignore such expiry times until
5041 HTTP/1.1 is fully implemented.
5043 WARNING: If turned on this may eventually cause some
5044 varying objects not intended for caching to get cached.
5047 NAME: request_entities
5049 LOC: Config.onoff.request_entities
5052 Squid defaults to deny GET and HEAD requests with request entities,
5053 as the meaning of such requests are undefined in the HTTP standard
5054 even if not explicitly forbidden.
5056 Set this directive to on if you have clients which insists
5057 on sending request entities in GET or HEAD requests. But be warned
5058 that there is server software (both proxies and web servers) which
5059 can fail to properly process this kind of request which may make you
5060 vulnerable to cache pollution attacks if enabled.
5063 NAME: request_header_access
5064 IFDEF: USE_HTTP_VIOLATIONS
5065 TYPE: http_header_access
5066 LOC: Config.request_header_access
5069 Usage: request_header_access header_name allow|deny [!]aclname ...
5071 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5072 this feature could make you liable for problems which it
5075 This option replaces the old 'anonymize_headers' and the
5076 older 'http_anonymizer' option with something that is much
5077 more configurable. A list of ACLs for each header name allows
5078 removal of specific header fields under specific conditions.
5080 This option only applies to outgoing HTTP request headers (i.e.,
5081 headers sent by Squid to the next HTTP hop such as a cache peer
5082 or an origin server). The option has no effect during cache hit
5083 detection. The equivalent adaptation vectoring point in ICAP
5084 terminology is post-cache REQMOD.
5086 The option is applied to individual outgoing request header
5087 fields. For each request header field F, Squid uses the first
5088 qualifying sets of request_header_access rules:
5090 1. Rules with header_name equal to F's name.
5091 2. Rules with header_name 'Other', provided F's name is not
5092 on the hard-coded list of commonly used HTTP header names.
5093 3. Rules with header_name 'All'.
5095 Within that qualifying rule set, rule ACLs are checked as usual.
5096 If ACLs of an "allow" rule match, the header field is allowed to
5097 go through as is. If ACLs of a "deny" rule match, the header is
5098 removed and request_header_replace is then checked to identify
5099 if the removed header has a replacement. If no rules within the
5100 set have matching ACLs, the header field is left as is.
5102 For example, to achieve the same behavior as the old
5103 'http_anonymizer standard' option, you should use:
5105 request_header_access From deny all
5106 request_header_access Referer deny all
5107 request_header_access Server deny all
5108 request_header_access User-Agent deny all
5109 request_header_access WWW-Authenticate deny all
5110 request_header_access Link deny all
5112 Or, to reproduce the old 'http_anonymizer paranoid' feature
5115 request_header_access Allow allow all
5116 request_header_access Authorization allow all
5117 request_header_access WWW-Authenticate allow all
5118 request_header_access Proxy-Authorization allow all
5119 request_header_access Proxy-Authenticate allow all
5120 request_header_access Cache-Control allow all
5121 request_header_access Content-Encoding allow all
5122 request_header_access Content-Length allow all
5123 request_header_access Content-Type allow all
5124 request_header_access Date allow all
5125 request_header_access Expires allow all
5126 request_header_access Host allow all
5127 request_header_access If-Modified-Since allow all
5128 request_header_access Last-Modified allow all
5129 request_header_access Location allow all
5130 request_header_access Pragma allow all
5131 request_header_access Accept allow all
5132 request_header_access Accept-Charset allow all
5133 request_header_access Accept-Encoding allow all
5134 request_header_access Accept-Language allow all
5135 request_header_access Content-Language allow all
5136 request_header_access Mime-Version allow all
5137 request_header_access Retry-After allow all
5138 request_header_access Title allow all
5139 request_header_access Connection allow all
5140 request_header_access All deny all
5142 although many of those are HTTP reply headers, and so should be
5143 controlled with the reply_header_access directive.
5145 By default, all headers are allowed (no anonymizing is
5149 NAME: reply_header_access
5150 IFDEF: USE_HTTP_VIOLATIONS
5151 TYPE: http_header_access
5152 LOC: Config.reply_header_access
5155 Usage: reply_header_access header_name allow|deny [!]aclname ...
5157 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5158 this feature could make you liable for problems which it
5161 This option only applies to reply headers, i.e., from the
5162 server to the client.
5164 This is the same as request_header_access, but in the other
5165 direction. Please see request_header_access for detailed
5168 For example, to achieve the same behavior as the old
5169 'http_anonymizer standard' option, you should use:
5171 reply_header_access From deny all
5172 reply_header_access Referer deny all
5173 reply_header_access Server deny all
5174 reply_header_access User-Agent deny all
5175 reply_header_access WWW-Authenticate deny all
5176 reply_header_access Link deny all
5178 Or, to reproduce the old 'http_anonymizer paranoid' feature
5181 reply_header_access Allow allow all
5182 reply_header_access Authorization allow all
5183 reply_header_access WWW-Authenticate allow all
5184 reply_header_access Proxy-Authorization allow all
5185 reply_header_access Proxy-Authenticate allow all
5186 reply_header_access Cache-Control allow all
5187 reply_header_access Content-Encoding allow all
5188 reply_header_access Content-Length allow all
5189 reply_header_access Content-Type allow all
5190 reply_header_access Date allow all
5191 reply_header_access Expires allow all
5192 reply_header_access Host allow all
5193 reply_header_access If-Modified-Since allow all
5194 reply_header_access Last-Modified allow all
5195 reply_header_access Location allow all
5196 reply_header_access Pragma allow all
5197 reply_header_access Accept allow all
5198 reply_header_access Accept-Charset allow all
5199 reply_header_access Accept-Encoding allow all
5200 reply_header_access Accept-Language allow all
5201 reply_header_access Content-Language allow all
5202 reply_header_access Mime-Version allow all
5203 reply_header_access Retry-After allow all
5204 reply_header_access Title allow all
5205 reply_header_access Connection allow all
5206 reply_header_access All deny all
5208 although the HTTP request headers won't be usefully controlled
5209 by this directive -- see request_header_access for details.
5211 By default, all headers are allowed (no anonymizing is
5215 NAME: request_header_replace header_replace
5216 IFDEF: USE_HTTP_VIOLATIONS
5217 TYPE: http_header_replace
5218 LOC: Config.request_header_access
5221 Usage: request_header_replace header_name message
5222 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
5224 This option allows you to change the contents of headers
5225 denied with request_header_access above, by replacing them
5226 with some fixed string. This replaces the old fake_user_agent
5229 This only applies to request headers, not reply headers.
5231 By default, headers are removed if denied.
5234 NAME: reply_header_replace
5235 IFDEF: USE_HTTP_VIOLATIONS
5236 TYPE: http_header_replace
5237 LOC: Config.reply_header_access
5240 Usage: reply_header_replace header_name message
5241 Example: reply_header_replace Server Foo/1.0
5243 This option allows you to change the contents of headers
5244 denied with reply_header_access above, by replacing them
5245 with some fixed string.
5247 This only applies to reply headers, not request headers.
5249 By default, headers are removed if denied.
5252 NAME: request_header_add
5253 TYPE: HeaderWithAclList
5254 LOC: Config.request_header_add
5257 Usage: request_header_add field-name field-value acl1 [acl2] ...
5258 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
5260 This option adds header fields to outgoing HTTP requests (i.e.,
5261 request headers sent by Squid to the next HTTP hop such as a
5262 cache peer or an origin server). The option has no effect during
5263 cache hit detection. The equivalent adaptation vectoring point
5264 in ICAP terminology is post-cache REQMOD.
5266 Field-name is a token specifying an HTTP header name. If a
5267 standard HTTP header name is used, Squid does not check whether
5268 the new header conflicts with any existing headers or violates
5269 HTTP rules. If the request to be modified already contains a
5270 field with the same name, the old field is preserved but the
5271 header field values are not merged.
5273 Field-value is either a token or a quoted string. If quoted
5274 string format is used, then the surrounding quotes are removed
5275 while escape sequences and %macros are processed.
5277 In theory, all of the logformat codes can be used as %macros.
5278 However, unlike logging (which happens at the very end of
5279 transaction lifetime), the transaction may not yet have enough
5280 information to expand a macro when the new header value is needed.
5281 And some information may already be available to Squid but not yet
5282 committed where the macro expansion code can access it (report
5283 such instances!). The macro will be expanded into a single dash
5284 ('-') in such cases. Not all macros have been tested.
5286 One or more Squid ACLs may be specified to restrict header
5287 injection to matching requests. As always in squid.conf, all
5288 ACLs in an option ACL list must be satisfied for the insertion
5289 to happen. The request_header_add option supports fast ACLs
5298 This option used to log custom information about the master
5299 transaction. For example, an admin may configure Squid to log
5300 which "user group" the transaction belongs to, where "user group"
5301 will be determined based on a set of ACLs and not [just]
5302 authentication information.
5303 Values of key/value pairs can be logged using %{key}note macros:
5305 note key value acl ...
5306 logformat myFormat ... %{key}note ...
5309 NAME: relaxed_header_parser
5310 COMMENT: on|off|warn
5312 LOC: Config.onoff.relaxed_header_parser
5315 In the default "on" setting Squid accepts certain forms
5316 of non-compliant HTTP messages where it is unambiguous
5317 what the sending application intended even if the message
5318 is not correctly formatted. The messages is then normalized
5319 to the correct form when forwarded by Squid.
5321 If set to "warn" then a warning will be emitted in cache.log
5322 each time such HTTP error is encountered.
5324 If set to "off" then such HTTP errors will cause the request
5325 or response to be rejected.
5330 -----------------------------------------------------------------------------
5333 NAME: forward_timeout
5336 LOC: Config.Timeout.forward
5339 This parameter specifies how long Squid should at most attempt in
5340 finding a forwarding path for the request before giving up.
5343 NAME: connect_timeout
5346 LOC: Config.Timeout.connect
5349 This parameter specifies how long to wait for the TCP connect to
5350 the requested server or peer to complete before Squid should
5351 attempt to find another path where to forward the request.
5354 NAME: peer_connect_timeout
5357 LOC: Config.Timeout.peer_connect
5360 This parameter specifies how long to wait for a pending TCP
5361 connection to a peer cache. The default is 30 seconds. You
5362 may also set different timeout values for individual neighbors
5363 with the 'connect-timeout' option on a 'cache_peer' line.
5369 LOC: Config.Timeout.read
5372 The read_timeout is applied on server-side connections. After
5373 each successful read(), the timeout will be extended by this
5374 amount. If no data is read again after this amount of time,
5375 the request is aborted and logged with ERR_READ_TIMEOUT. The
5376 default is 15 minutes.
5382 LOC: Config.Timeout.write
5385 This timeout is tracked for all connections that have data
5386 available for writing and are waiting for the socket to become
5387 ready. After each successful write, the timeout is extended by
5388 the configured amount. If Squid has data to write but the
5389 connection is not ready for the configured duration, the
5390 transaction associated with the connection is terminated. The
5391 default is 15 minutes.
5394 NAME: request_timeout
5396 LOC: Config.Timeout.request
5399 How long to wait for complete HTTP request headers after initial
5400 connection establishment.
5403 NAME: client_idle_pconn_timeout persistent_request_timeout
5405 LOC: Config.Timeout.clientIdlePconn
5408 How long to wait for the next HTTP request on a persistent
5409 client connection after the previous request completes.
5412 NAME: client_lifetime
5415 LOC: Config.Timeout.lifetime
5418 The maximum amount of time a client (browser) is allowed to
5419 remain connected to the cache process. This protects the Cache
5420 from having a lot of sockets (and hence file descriptors) tied up
5421 in a CLOSE_WAIT state from remote clients that go away without
5422 properly shutting down (either because of a network failure or
5423 because of a poor client implementation). The default is one
5426 NOTE: The default value is intended to be much larger than any
5427 client would ever need to be connected to your cache. You
5428 should probably change client_lifetime only as a last resort.
5429 If you seem to have many client connections tying up
5430 filedescriptors, we recommend first tuning the read_timeout,
5431 request_timeout, persistent_request_timeout and quick_abort values.
5434 NAME: half_closed_clients
5436 LOC: Config.onoff.half_closed_clients
5439 Some clients may shutdown the sending side of their TCP
5440 connections, while leaving their receiving sides open. Sometimes,
5441 Squid can not tell the difference between a half-closed and a
5442 fully-closed TCP connection.
5444 By default, Squid will immediately close client connections when
5445 read(2) returns "no more data to read."
5447 Change this option to 'on' and Squid will keep open connections
5448 until a read(2) or write(2) on the socket returns an error.
5449 This may show some benefits for reverse proxies. But if not
5450 it is recommended to leave OFF.
5453 NAME: server_idle_pconn_timeout pconn_timeout
5455 LOC: Config.Timeout.serverIdlePconn
5458 Timeout for idle persistent connections to servers and other
5465 LOC: Ident::TheConfig.timeout
5468 Maximum time to wait for IDENT lookups to complete.
5470 If this is too high, and you enabled IDENT lookups from untrusted
5471 users, you might be susceptible to denial-of-service by having
5472 many ident requests going at once.
5475 NAME: shutdown_lifetime
5478 LOC: Config.shutdownLifetime
5481 When SIGTERM or SIGHUP is received, the cache is put into
5482 "shutdown pending" mode until all active sockets are closed.
5483 This value is the lifetime to set for all open descriptors
5484 during shutdown mode. Any active clients after this many
5485 seconds will receive a 'timeout' message.
5489 ADMINISTRATIVE PARAMETERS
5490 -----------------------------------------------------------------------------
5496 LOC: Config.adminEmail
5498 Email-address of local cache manager who will receive
5499 mail if the cache dies. The default is "webmaster."
5505 LOC: Config.EmailFrom
5507 From: email-address for mail sent when the cache dies.
5508 The default is to use 'appname@unique_hostname'.
5509 Default appname value is "squid", can be changed into
5510 src/globals.h before building squid.
5516 LOC: Config.EmailProgram
5518 Email program used to send mail if the cache dies.
5519 The default is "mail". The specified program must comply
5520 with the standard Unix mail syntax:
5521 mail-program recipient < mailfile
5523 Optional command line options can be specified.
5526 NAME: cache_effective_user
5528 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
5529 LOC: Config.effectiveUser
5531 If you start Squid as root, it will change its effective/real
5532 UID/GID to the user specified below. The default is to change
5533 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
5534 see also; cache_effective_group
5537 NAME: cache_effective_group
5540 LOC: Config.effectiveGroup
5542 Squid sets the GID to the effective user's default group ID
5543 (taken from the password file) and supplementary group list
5544 from the groups membership.
5546 If you want Squid to run with a specific GID regardless of
5547 the group memberships of the effective user then set this
5548 to the group (or GID) you want Squid to run as. When set
5549 all other group privileges of the effective user are ignored
5550 and only this GID is effective. If Squid is not started as
5551 root the user starting Squid MUST be member of the specified
5554 This option is not recommended by the Squid Team.
5555 Our preference is for administrators to configure a secure
5556 user account for squid with UID/GID matching system policies.
5559 NAME: httpd_suppress_version_string
5563 LOC: Config.onoff.httpd_suppress_version_string
5565 Suppress Squid version string info in HTTP headers and HTML error pages.
5568 NAME: visible_hostname
5570 LOC: Config.visibleHostname
5573 If you want to present a special hostname in error messages, etc,
5574 define this. Otherwise, the return value of gethostname()
5575 will be used. If you have multiple caches in a cluster and
5576 get errors about IP-forwarding you must set them to have individual
5577 names with this setting.
5580 NAME: unique_hostname
5582 LOC: Config.uniqueHostname
5585 If you want to have multiple machines with the same
5586 'visible_hostname' you must give each machine a different
5587 'unique_hostname' so forwarding loops can be detected.
5590 NAME: hostname_aliases
5592 LOC: Config.hostnameAliases
5595 A list of other DNS names your cache has.
5603 Minimum umask which should be enforced while the proxy
5604 is running, in addition to the umask set at startup.
5606 For a traditional octal representation of umasks, start
5611 OPTIONS FOR THE CACHE REGISTRATION SERVICE
5612 -----------------------------------------------------------------------------
5614 This section contains parameters for the (optional) cache
5615 announcement service. This service is provided to help
5616 cache administrators locate one another in order to join or
5617 create cache hierarchies.
5619 An 'announcement' message is sent (via UDP) to the registration
5620 service by Squid. By default, the announcement message is NOT
5621 SENT unless you enable it with 'announce_period' below.
5623 The announcement message includes your hostname, plus the
5624 following information from this configuration file:
5630 All current information is processed regularly and made
5631 available on the Web at http://www.ircache.net/Cache/Tracker/.
5634 NAME: announce_period
5636 LOC: Config.Announce.period
5639 This is how frequently to send cache announcements. The
5640 default is `0' which disables sending the announcement
5643 To enable announcing your cache, just set an announce period.
5646 announce_period 1 day
5651 DEFAULT: tracker.ircache.net
5652 LOC: Config.Announce.host
5658 LOC: Config.Announce.file
5664 LOC: Config.Announce.port
5666 announce_host and announce_port set the hostname and port
5667 number where the registration message will be sent.
5669 Hostname will default to 'tracker.ircache.net' and port will
5670 default default to 3131. If the 'filename' argument is given,
5671 the contents of that file will be included in the announce
5676 HTTPD-ACCELERATOR OPTIONS
5677 -----------------------------------------------------------------------------
5680 NAME: httpd_accel_surrogate_id
5683 LOC: Config.Accel.surrogate_id
5685 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
5686 need an identification token to allow control targeting. Because
5687 a farm of surrogates may all perform the same tasks, they may share
5688 an identification token.
5690 The default ID is the visible_hostname
5693 NAME: http_accel_surrogate_remote
5697 LOC: Config.onoff.surrogate_is_remote
5699 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
5700 Set this to on to have squid behave as a remote surrogate.
5704 IFDEF: USE_SQUID_ESI
5705 COMMENT: libxml2|expat|custom
5707 LOC: ESIParser::Type
5710 ESI markup is not strictly XML compatible. The custom ESI parser
5711 will give higher performance, but cannot handle non ASCII character
5716 DELAY POOL PARAMETERS
5717 -----------------------------------------------------------------------------
5721 TYPE: delay_pool_count
5723 IFDEF: USE_DELAY_POOLS
5726 This represents the number of delay pools to be used. For example,
5727 if you have one class 2 delay pool and one class 3 delays pool, you
5728 have a total of 2 delay pools.
5732 TYPE: delay_pool_class
5734 IFDEF: USE_DELAY_POOLS
5737 This defines the class of each delay pool. There must be exactly one
5738 delay_class line for each delay pool. For example, to define two
5739 delay pools, one of class 2 and one of class 3, the settings above
5743 delay_pools 4 # 4 delay pools
5744 delay_class 1 2 # pool 1 is a class 2 pool
5745 delay_class 2 3 # pool 2 is a class 3 pool
5746 delay_class 3 4 # pool 3 is a class 4 pool
5747 delay_class 4 5 # pool 4 is a class 5 pool
5749 The delay pool classes are:
5751 class 1 Everything is limited by a single aggregate
5754 class 2 Everything is limited by a single aggregate
5755 bucket as well as an "individual" bucket chosen
5756 from bits 25 through 32 of the IPv4 address.
5758 class 3 Everything is limited by a single aggregate
5759 bucket as well as a "network" bucket chosen
5760 from bits 17 through 24 of the IP address and a
5761 "individual" bucket chosen from bits 17 through
5762 32 of the IPv4 address.
5764 class 4 Everything in a class 3 delay pool, with an
5765 additional limit on a per user basis. This
5766 only takes effect if the username is established
5767 in advance - by forcing authentication in your
5770 class 5 Requests are grouped according their tag (see
5771 external_acl's tag= reply).
5774 Each pool also requires a delay_parameters directive to configure the pool size
5775 and speed limits used whenever the pool is applied to a request. Along with
5776 a set of delay_access directives to determine when it is used.
5778 NOTE: If an IP address is a.b.c.d
5779 -> bits 25 through 32 are "d"
5780 -> bits 17 through 24 are "c"
5781 -> bits 17 through 32 are "c * 256 + d"
5783 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
5784 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
5788 TYPE: delay_pool_access
5790 IFDEF: USE_DELAY_POOLS
5793 This is used to determine which delay pool a request falls into.
5795 delay_access is sorted per pool and the matching starts with pool 1,
5796 then pool 2, ..., and finally pool N. The first delay pool where the
5797 request is allowed is selected for the request. If it does not allow
5798 the request to any pool then the request is not delayed (default).
5800 For example, if you want some_big_clients in delay
5801 pool 1 and lotsa_little_clients in delay pool 2:
5804 delay_access 1 allow some_big_clients
5805 delay_access 1 deny all
5806 delay_access 2 allow lotsa_little_clients
5807 delay_access 2 deny all
5808 delay_access 3 allow authenticated_clients
5811 NAME: delay_parameters
5812 TYPE: delay_pool_rates
5814 IFDEF: USE_DELAY_POOLS
5817 This defines the parameters for a delay pool. Each delay pool has
5818 a number of "buckets" associated with it, as explained in the
5819 description of delay_class.
5821 For a class 1 delay pool, the syntax is:
5823 delay_parameters pool aggregate
5825 For a class 2 delay pool:
5827 delay_parameters pool aggregate individual
5829 For a class 3 delay pool:
5831 delay_parameters pool aggregate network individual
5833 For a class 4 delay pool:
5835 delay_parameters pool aggregate network individual user
5837 For a class 5 delay pool:
5839 delay_parameters pool tagrate
5841 The option variables are:
5843 pool a pool number - ie, a number between 1 and the
5844 number specified in delay_pools as used in
5847 aggregate the speed limit parameters for the aggregate bucket
5850 individual the speed limit parameters for the individual
5851 buckets (class 2, 3).
5853 network the speed limit parameters for the network buckets
5856 user the speed limit parameters for the user buckets
5859 tagrate the speed limit parameters for the tag buckets
5862 A pair of delay parameters is written restore/maximum, where restore is
5863 the number of bytes (not bits - modem and network speeds are usually
5864 quoted in bits) per second placed into the bucket, and maximum is the
5865 maximum number of bytes which can be in the bucket at any time.
5867 There must be one delay_parameters line for each delay pool.
5870 For example, if delay pool number 1 is a class 2 delay pool as in the
5871 above example, and is being used to strictly limit each host to 64Kbit/sec
5872 (plus overheads), with no overall limit, the line is:
5874 delay_parameters 1 -1/-1 8000/8000
5876 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
5878 Note that the figure -1 is used to represent "unlimited".
5881 And, if delay pool number 2 is a class 3 delay pool as in the above
5882 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
5883 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
5884 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
5885 to permit a decent web page to be downloaded at a decent speed
5886 (if the network is not being limited due to overuse) but slow down
5887 large downloads more significantly:
5889 delay_parameters 2 32000/32000 8000/8000 600/8000
5891 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
5892 8 x 8000 KByte/sec -> 64Kbit/sec.
5893 8 x 600 Byte/sec -> 4800bit/sec.
5896 Finally, for a class 4 delay pool as in the example - each user will
5897 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
5899 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
5902 NAME: delay_initial_bucket_level
5903 COMMENT: (percent, 0-100)
5906 IFDEF: USE_DELAY_POOLS
5907 LOC: Config.Delay.initial
5909 The initial bucket percentage is used to determine how much is put
5910 in each bucket when squid starts, is reconfigured, or first notices
5911 a host accessing it (in class 2 and class 3, individual hosts and
5912 networks only have buckets associated with them once they have been
5917 CLIENT DELAY POOL PARAMETERS
5918 -----------------------------------------------------------------------------
5921 NAME: client_delay_pools
5922 TYPE: client_delay_pool_count
5924 IFDEF: USE_DELAY_POOLS
5925 LOC: Config.ClientDelay
5927 This option specifies the number of client delay pools used. It must
5928 preceed other client_delay_* options.
5931 client_delay_pools 2
5934 NAME: client_delay_initial_bucket_level
5935 COMMENT: (percent, 0-no_limit)
5938 IFDEF: USE_DELAY_POOLS
5939 LOC: Config.ClientDelay.initial
5941 This option determines the initial bucket size as a percentage of
5942 max_bucket_size from client_delay_parameters. Buckets are created
5943 at the time of the "first" connection from the matching IP. Idle
5944 buckets are periodically deleted up.
5946 You can specify more than 100 percent but note that such "oversized"
5947 buckets are not refilled until their size goes down to max_bucket_size
5948 from client_delay_parameters.
5951 client_delay_initial_bucket_level 50
5954 NAME: client_delay_parameters
5955 TYPE: client_delay_pool_rates
5957 IFDEF: USE_DELAY_POOLS
5958 LOC: Config.ClientDelay
5961 This option configures client-side bandwidth limits using the
5964 client_delay_parameters pool speed_limit max_bucket_size
5966 pool is an integer ID used for client_delay_access matching.
5968 speed_limit is bytes added to the bucket per second.
5970 max_bucket_size is the maximum size of a bucket, enforced after any
5971 speed_limit additions.
5973 Please see the delay_parameters option for more information and
5977 client_delay_parameters 1 1024 2048
5978 client_delay_parameters 2 51200 16384
5981 NAME: client_delay_access
5982 TYPE: client_delay_pool_access
5984 IFDEF: USE_DELAY_POOLS
5985 LOC: Config.ClientDelay
5988 This option determines the client-side delay pool for the
5991 client_delay_access pool_ID allow|deny acl_name
5993 All client_delay_access options are checked in their pool ID
5994 order, starting with pool 1. The first checked pool with allowed
5995 request is selected for the request. If no ACL matches or there
5996 are no client_delay_access options, the request bandwidth is not
5999 The ACL-selected pool is then used to find the
6000 client_delay_parameters for the request. Client-side pools are
6001 not used to aggregate clients. Clients are always aggregated
6002 based on their source IP addresses (one bucket per source IP).
6004 Please see delay_access for more examples.
6007 client_delay_access 1 allow low_rate_network
6008 client_delay_access 2 allow vips_network
6012 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6013 -----------------------------------------------------------------------------
6018 LOC: Config.Wccp.router
6022 Use this option to define your WCCP ``home'' router for
6025 wccp_router supports a single WCCP(v1) router
6027 wccp2_router supports multiple WCCPv2 routers
6029 only one of the two may be used at the same time and defines
6030 which version of WCCP to use.
6034 TYPE: IpAddress_list
6035 LOC: Config.Wccp2.router
6039 Use this option to define your WCCP ``home'' router for
6042 wccp_router supports a single WCCP(v1) router
6044 wccp2_router supports multiple WCCPv2 routers
6046 only one of the two may be used at the same time and defines
6047 which version of WCCP to use.
6052 LOC: Config.Wccp.version
6056 This directive is only relevant if you need to set up WCCP(v1)
6057 to some very old and end-of-life Cisco routers. In all other
6058 setups it must be left unset or at the default setting.
6059 It defines an internal version in the WCCP(v1) protocol,
6060 with version 4 being the officially documented protocol.
6062 According to some users, Cisco IOS 11.2 and earlier only
6063 support WCCP version 3. If you're using that or an earlier
6064 version of IOS, you may need to change this value to 3, otherwise
6065 do not specify this parameter.
6068 NAME: wccp2_rebuild_wait
6070 LOC: Config.Wccp2.rebuildwait
6074 If this is enabled Squid will wait for the cache dir rebuild to finish
6075 before sending the first wccp2 HereIAm packet
6078 NAME: wccp2_forwarding_method
6080 LOC: Config.Wccp2.forwarding_method
6084 WCCP2 allows the setting of forwarding methods between the
6085 router/switch and the cache. Valid values are as follows:
6087 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6088 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6090 Currently (as of IOS 12.4) cisco routers only support GRE.
6091 Cisco switches only support the L2 redirect assignment method.
6094 NAME: wccp2_return_method
6096 LOC: Config.Wccp2.return_method
6100 WCCP2 allows the setting of return methods between the
6101 router/switch and the cache for packets that the cache
6102 decides not to handle. Valid values are as follows:
6104 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6105 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6107 Currently (as of IOS 12.4) cisco routers only support GRE.
6108 Cisco switches only support the L2 redirect assignment.
6110 If the "ip wccp redirect exclude in" command has been
6111 enabled on the cache interface, then it is still safe for
6112 the proxy server to use a l2 redirect method even if this
6113 option is set to GRE.
6116 NAME: wccp2_assignment_method
6118 LOC: Config.Wccp2.assignment_method
6122 WCCP2 allows the setting of methods to assign the WCCP hash
6123 Valid values are as follows:
6125 hash - Hash assignment
6126 mask - Mask assignment
6128 As a general rule, cisco routers support the hash assignment method
6129 and cisco switches support the mask assignment method.
6134 LOC: Config.Wccp2.info
6135 DEFAULT_IF_NONE: standard 0
6138 WCCP2 allows for multiple traffic services. There are two
6139 types: "standard" and "dynamic". The standard type defines
6140 one service id - http (id 0). The dynamic service ids can be from
6141 51 to 255 inclusive. In order to use a dynamic service id
6142 one must define the type of traffic to be redirected; this is done
6143 using the wccp2_service_info option.
6145 The "standard" type does not require a wccp2_service_info option,
6146 just specifying the service id will suffice.
6148 MD5 service authentication can be enabled by adding
6149 "password=<password>" to the end of this service declaration.
6153 wccp2_service standard 0 # for the 'web-cache' standard service
6154 wccp2_service dynamic 80 # a dynamic service type which will be
6155 # fleshed out with subsequent options.
6156 wccp2_service standard 0 password=foo
6159 NAME: wccp2_service_info
6160 TYPE: wccp2_service_info
6161 LOC: Config.Wccp2.info
6165 Dynamic WCCPv2 services require further information to define the
6166 traffic you wish to have diverted.
6170 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
6171 priority=<priority> ports=<port>,<port>..
6173 The relevant WCCPv2 flags:
6174 + src_ip_hash, dst_ip_hash
6175 + source_port_hash, dst_port_hash
6176 + src_ip_alt_hash, dst_ip_alt_hash
6177 + src_port_alt_hash, dst_port_alt_hash
6180 The port list can be one to eight entries.
6184 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
6185 priority=240 ports=80
6187 Note: the service id must have been defined by a previous
6188 'wccp2_service dynamic <id>' entry.
6193 LOC: Config.Wccp2.weight
6197 Each cache server gets assigned a set of the destination
6198 hash proportional to their weight.
6203 LOC: Config.Wccp.address
6210 LOC: Config.Wccp2.address
6214 Use this option if you require WCCP to use a specific
6217 The default behavior is to not bind to any specific address.
6221 PERSISTENT CONNECTION HANDLING
6222 -----------------------------------------------------------------------------
6224 Also see "pconn_timeout" in the TIMEOUTS section
6227 NAME: client_persistent_connections
6229 LOC: Config.onoff.client_pconns
6233 NAME: server_persistent_connections
6235 LOC: Config.onoff.server_pconns
6238 Persistent connection support for clients and servers. By
6239 default, Squid uses persistent connections (when allowed)
6240 with its clients and servers. You can use these options to
6241 disable persistent connections with clients and/or servers.
6244 NAME: persistent_connection_after_error
6246 LOC: Config.onoff.error_pconns
6249 With this directive the use of persistent connections after
6250 HTTP errors can be disabled. Useful if you have clients
6251 who fail to handle errors on persistent connections proper.
6254 NAME: detect_broken_pconn
6256 LOC: Config.onoff.detect_broken_server_pconns
6259 Some servers have been found to incorrectly signal the use
6260 of HTTP/1.0 persistent connections even on replies not
6261 compatible, causing significant delays. This server problem
6262 has mostly been seen on redirects.
6264 By enabling this directive Squid attempts to detect such
6265 broken replies and automatically assume the reply is finished
6266 after 10 seconds timeout.
6270 CACHE DIGEST OPTIONS
6271 -----------------------------------------------------------------------------
6274 NAME: digest_generation
6275 IFDEF: USE_CACHE_DIGESTS
6277 LOC: Config.onoff.digest_generation
6280 This controls whether the server will generate a Cache Digest
6281 of its contents. By default, Cache Digest generation is
6282 enabled if Squid is compiled with --enable-cache-digests defined.
6285 NAME: digest_bits_per_entry
6286 IFDEF: USE_CACHE_DIGESTS
6288 LOC: Config.digest.bits_per_entry
6291 This is the number of bits of the server's Cache Digest which
6292 will be associated with the Digest entry for a given HTTP
6293 Method and URL (public key) combination. The default is 5.
6296 NAME: digest_rebuild_period
6297 IFDEF: USE_CACHE_DIGESTS
6300 LOC: Config.digest.rebuild_period
6303 This is the wait time between Cache Digest rebuilds.
6306 NAME: digest_rewrite_period
6308 IFDEF: USE_CACHE_DIGESTS
6310 LOC: Config.digest.rewrite_period
6313 This is the wait time between Cache Digest writes to
6317 NAME: digest_swapout_chunk_size
6320 IFDEF: USE_CACHE_DIGESTS
6321 LOC: Config.digest.swapout_chunk_size
6324 This is the number of bytes of the Cache Digest to write to
6325 disk at a time. It defaults to 4096 bytes (4KB), the Squid
6329 NAME: digest_rebuild_chunk_percentage
6330 COMMENT: (percent, 0-100)
6331 IFDEF: USE_CACHE_DIGESTS
6333 LOC: Config.digest.rebuild_chunk_percentage
6336 This is the percentage of the Cache Digest to be scanned at a
6337 time. By default it is set to 10% of the Cache Digest.
6342 -----------------------------------------------------------------------------
6347 LOC: Config.Port.snmp
6351 The port number where Squid listens for SNMP requests. To enable
6352 SNMP support set this to a suitable port number. Port number
6353 3401 is often used for the Squid SNMP agent. By default it's
6354 set to "0" (disabled)
6362 LOC: Config.accessList.snmp
6363 DEFAULT_IF_NONE: deny all
6366 Allowing or denying access to the SNMP port.
6368 All access to the agent is denied by default.
6371 snmp_access allow|deny [!]aclname ...
6373 This clause only supports fast acl types.
6374 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6376 snmp_access allow snmppublic localhost
6377 snmp_access deny all
6380 NAME: snmp_incoming_address
6382 LOC: Config.Addrs.snmp_incoming
6387 NAME: snmp_outgoing_address
6389 LOC: Config.Addrs.snmp_outgoing
6393 Just like 'udp_incoming_address', but for the SNMP port.
6395 snmp_incoming_address is used for the SNMP socket receiving
6396 messages from SNMP agents.
6397 snmp_outgoing_address is used for SNMP packets returned to SNMP
6400 The default snmp_incoming_address is to listen on all
6401 available network interfaces.
6403 If snmp_outgoing_address is not set it will use the same socket
6404 as snmp_incoming_address. Only change this if you want to have
6405 SNMP replies sent using another address than where this Squid
6406 listens for SNMP queries.
6408 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
6409 the same value since they both use port 3401.
6414 -----------------------------------------------------------------------------
6417 NAME: icp_port udp_port
6420 LOC: Config.Port.icp
6422 The port number where Squid sends and receives ICP queries to
6423 and from neighbor caches. The standard UDP port for ICP is 3130.
6424 Default is disabled (0).
6427 icp_port @DEFAULT_ICP_PORT@
6434 LOC: Config.Port.htcp
6436 The port number where Squid sends and receives HTCP queries to
6437 and from neighbor caches. To turn it on you want to set it to
6438 4827. By default it is set to "0" (disabled).
6444 NAME: log_icp_queries
6448 LOC: Config.onoff.log_udp
6450 If set, ICP queries are logged to access.log. You may wish
6451 do disable this if your ICP load is VERY high to speed things
6452 up or to simplify log analysis.
6455 NAME: udp_incoming_address
6457 LOC:Config.Addrs.udp_incoming
6460 udp_incoming_address is used for UDP packets received from other
6463 The default behavior is to not bind to any specific address.
6465 Only change this if you want to have all UDP queries received on
6466 a specific interface/address.
6468 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
6469 modules. Altering it will affect all of them in the same manner.
6471 see also; udp_outgoing_address
6473 NOTE, udp_incoming_address and udp_outgoing_address can not
6474 have the same value since they both use the same port.
6477 NAME: udp_outgoing_address
6479 LOC: Config.Addrs.udp_outgoing
6482 udp_outgoing_address is used for UDP packets sent out to other
6485 The default behavior is to not bind to any specific address.
6487 Instead it will use the same socket as udp_incoming_address.
6488 Only change this if you want to have UDP queries sent using another
6489 address than where this Squid listens for UDP queries from other
6492 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
6493 modules. Altering it will affect all of them in the same manner.
6495 see also; udp_incoming_address
6497 NOTE, udp_incoming_address and udp_outgoing_address can not
6498 have the same value since they both use the same port.
6505 LOC: Config.onoff.icp_hit_stale
6507 If you want to return ICP_HIT for stale cache objects, set this
6508 option to 'on'. If you have sibling relationships with caches
6509 in other administrative domains, this should be 'off'. If you only
6510 have sibling relationships with caches under your control,
6511 it is probably okay to set this to 'on'.
6512 If set to 'on', your siblings should use the option "allow-miss"
6513 on their cache_peer lines for connecting to you.
6516 NAME: minimum_direct_hops
6519 LOC: Config.minDirectHops
6521 If using the ICMP pinging stuff, do direct fetches for sites
6522 which are no more than this many hops away.
6525 NAME: minimum_direct_rtt
6528 LOC: Config.minDirectRtt
6530 If using the ICMP pinging stuff, do direct fetches for sites
6531 which are no more than this many rtt milliseconds away.
6537 LOC: Config.Netdb.low
6543 LOC: Config.Netdb.high
6545 The low and high water marks for the ICMP measurement
6546 database. These are counts, not percents. The defaults are
6547 900 and 1000. When the high water mark is reached, database
6548 entries will be deleted until the low mark is reached.
6551 NAME: netdb_ping_period
6553 LOC: Config.Netdb.period
6556 The minimum period for measuring a site. There will be at
6557 least this much delay between successive pings to the same
6558 network. The default is five minutes.
6565 LOC: Config.onoff.query_icmp
6567 If you want to ask your peers to include ICMP data in their ICP
6568 replies, enable this option.
6570 If your peer has configured Squid (during compilation) with
6571 '--enable-icmp' that peer will send ICMP pings to origin server
6572 sites of the URLs it receives. If you enable this option the
6573 ICP replies from that peer will include the ICMP data (if available).
6574 Then, when choosing a parent cache, Squid will choose the parent with
6575 the minimal RTT to the origin server. When this happens, the
6576 hierarchy field of the access.log will be
6577 "CLOSEST_PARENT_MISS". This option is off by default.
6580 NAME: test_reachability
6584 LOC: Config.onoff.test_reachability
6586 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
6587 instead of ICP_MISS if the target host is NOT in the ICMP
6588 database, or has a zero RTT.
6591 NAME: icp_query_timeout
6595 LOC: Config.Timeout.icp_query
6597 Normally Squid will automatically determine an optimal ICP
6598 query timeout value based on the round-trip-time of recent ICP
6599 queries. If you want to override the value determined by
6600 Squid, set this 'icp_query_timeout' to a non-zero value. This
6601 value is specified in MILLISECONDS, so, to use a 2-second
6602 timeout (the old default), you would write:
6604 icp_query_timeout 2000
6607 NAME: maximum_icp_query_timeout
6611 LOC: Config.Timeout.icp_query_max
6613 Normally the ICP query timeout is determined dynamically. But
6614 sometimes it can lead to very large values (say 5 seconds).
6615 Use this option to put an upper limit on the dynamic timeout
6616 value. Do NOT use this option to always use a fixed (instead
6617 of a dynamic) timeout value. To set a fixed timeout see the
6618 'icp_query_timeout' directive.
6621 NAME: minimum_icp_query_timeout
6625 LOC: Config.Timeout.icp_query_min
6627 Normally the ICP query timeout is determined dynamically. But
6628 sometimes it can lead to very small timeouts, even lower than
6629 the normal latency variance on your link due to traffic.
6630 Use this option to put an lower limit on the dynamic timeout
6631 value. Do NOT use this option to always use a fixed (instead
6632 of a dynamic) timeout value. To set a fixed timeout see the
6633 'icp_query_timeout' directive.
6636 NAME: background_ping_rate
6640 LOC: Config.backgroundPingRate
6642 Controls how often the ICP pings are sent to siblings that
6643 have background-ping set.
6647 MULTICAST ICP OPTIONS
6648 -----------------------------------------------------------------------------
6653 LOC: Config.mcast_group_list
6656 This tag specifies a list of multicast groups which your server
6657 should join to receive multicasted ICP queries.
6659 NOTE! Be very careful what you put here! Be sure you
6660 understand the difference between an ICP _query_ and an ICP
6661 _reply_. This option is to be set only if you want to RECEIVE
6662 multicast queries. Do NOT set this option to SEND multicast
6663 ICP (use cache_peer for that). ICP replies are always sent via
6664 unicast, so this option does not affect whether or not you will
6665 receive replies from multicast group members.
6667 You must be very careful to NOT use a multicast address which
6668 is already in use by another group of caches.
6670 If you are unsure about multicast, please read the Multicast
6671 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
6673 Usage: mcast_groups 239.128.16.128 224.0.1.20
6675 By default, Squid doesn't listen on any multicast groups.
6678 NAME: mcast_miss_addr
6679 IFDEF: MULTICAST_MISS_STREAM
6681 LOC: Config.mcast_miss.addr
6684 If you enable this option, every "cache miss" URL will
6685 be sent out on the specified multicast address.
6687 Do not enable this option unless you are are absolutely
6688 certain you understand what you are doing.
6691 NAME: mcast_miss_ttl
6692 IFDEF: MULTICAST_MISS_STREAM
6694 LOC: Config.mcast_miss.ttl
6697 This is the time-to-live value for packets multicasted
6698 when multicasting off cache miss URLs is enabled. By
6699 default this is set to 'site scope', i.e. 16.
6702 NAME: mcast_miss_port
6703 IFDEF: MULTICAST_MISS_STREAM
6705 LOC: Config.mcast_miss.port
6708 This is the port number to be used in conjunction with
6712 NAME: mcast_miss_encode_key
6713 IFDEF: MULTICAST_MISS_STREAM
6715 LOC: Config.mcast_miss.encode_key
6716 DEFAULT: XXXXXXXXXXXXXXXX
6718 The URLs that are sent in the multicast miss stream are
6719 encrypted. This is the encryption key.
6722 NAME: mcast_icp_query_timeout
6726 LOC: Config.Timeout.mcast_icp_query
6728 For multicast peers, Squid regularly sends out ICP "probes" to
6729 count how many other peers are listening on the given multicast
6730 address. This value specifies how long Squid should wait to
6731 count all the replies. The default is 2000 msec, or 2
6736 INTERNAL ICON OPTIONS
6737 -----------------------------------------------------------------------------
6740 NAME: icon_directory
6742 LOC: Config.icons.directory
6743 DEFAULT: @DEFAULT_ICON_DIR@
6745 Where the icons are stored. These are normally kept in
6749 NAME: global_internal_static
6751 LOC: Config.onoff.global_internal_static
6754 This directive controls is Squid should intercept all requests for
6755 /squid-internal-static/ no matter which host the URL is requesting
6756 (default on setting), or if nothing special should be done for
6757 such URLs (off setting). The purpose of this directive is to make
6758 icons etc work better in complex cache hierarchies where it may
6759 not always be possible for all corners in the cache mesh to reach
6760 the server generating a directory listing.
6763 NAME: short_icon_urls
6765 LOC: Config.icons.use_short_names
6768 If this is enabled Squid will use short URLs for icons.
6769 If disabled it will revert to the old behavior of including
6770 it's own name and port in the URL.
6772 If you run a complex cache hierarchy with a mix of Squid and
6773 other proxies you may need to disable this directive.
6778 -----------------------------------------------------------------------------
6781 NAME: error_directory
6783 LOC: Config.errorDirectory
6786 If you wish to create your own versions of the default
6787 error files to customize them to suit your company copy
6788 the error/template files to another directory and point
6791 WARNING: This option will disable multi-language support
6792 on error pages if used.
6794 The squid developers are interested in making squid available in
6795 a wide variety of languages. If you are making translations for a
6796 language that Squid does not currently provide please consider
6797 contributing your translation back to the project.
6798 http://wiki.squid-cache.org/Translations
6800 The squid developers working on translations are happy to supply drop-in
6801 translated error files in exchange for any new language contributions.
6804 NAME: error_default_language
6805 IFDEF: USE_ERR_LOCALES
6807 LOC: Config.errorDefaultLanguage
6810 Set the default language which squid will send error pages in
6811 if no existing translation matches the clients language
6814 If unset (default) generic English will be used.
6816 The squid developers are interested in making squid available in
6817 a wide variety of languages. If you are interested in making
6818 translations for any language see the squid wiki for details.
6819 http://wiki.squid-cache.org/Translations
6822 NAME: error_log_languages
6823 IFDEF: USE_ERR_LOCALES
6825 LOC: Config.errorLogMissingLanguages
6828 Log to cache.log what languages users are attempting to
6829 auto-negotiate for translations.
6831 Successful negotiations are not logged. Only failures
6832 have meaning to indicate that Squid may need an upgrade
6833 of its error page translations.
6836 NAME: err_page_stylesheet
6838 LOC: Config.errorStylesheet
6839 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
6841 CSS Stylesheet to pattern the display of Squid default error pages.
6843 For information on CSS see http://www.w3.org/Style/CSS/
6848 LOC: Config.errHtmlText
6851 HTML text to include in error messages. Make this a "mailto"
6852 URL to your admin address, or maybe just a link to your
6853 organizations Web page.
6855 To include this in your error messages, you must rewrite
6856 the error template files (found in the "errors" directory).
6857 Wherever you want the 'err_html_text' line to appear,
6858 insert a %L tag in the error template file.
6861 NAME: email_err_data
6864 LOC: Config.onoff.emailErrData
6867 If enabled, information about the occurred error will be
6868 included in the mailto links of the ERR pages (if %W is set)
6869 so that the email body contains the data.
6870 Syntax is <A HREF="mailto:%w%W">%w</A>
6875 LOC: Config.denyInfoList
6878 Usage: deny_info err_page_name acl
6879 or deny_info http://... acl
6880 or deny_info TCP_RESET acl
6882 This can be used to return a ERR_ page for requests which
6883 do not pass the 'http_access' rules. Squid remembers the last
6884 acl it evaluated in http_access, and if a 'deny_info' line exists
6885 for that ACL Squid returns a corresponding error page.
6887 The acl is typically the last acl on the http_access deny line which
6888 denied access. The exceptions to this rule are:
6889 - When Squid needs to request authentication credentials. It's then
6890 the first authentication related acl encountered
6891 - When none of the http_access lines matches. It's then the last
6892 acl processed on the last http_access line.
6893 - When the decision to deny access was made by an adaptation service,
6894 the acl name is the corresponding eCAP or ICAP service_name.
6896 NP: If providing your own custom error pages with error_directory
6897 you may also specify them by your custom file name:
6898 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
6900 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
6901 may be specified by prefixing the file name with the code and a colon.
6902 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
6904 Alternatively you can tell Squid to reset the TCP connection
6905 by specifying TCP_RESET.
6907 Or you can specify an error URL or URL pattern. The browsers will
6908 get redirected to the specified URL after formatting tags have
6909 been replaced. Redirect will be done with 302 or 307 according to
6910 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
6911 the URL. e.g. 303:http://example.com/
6914 %a - username (if available. Password NOT included)
6917 %E - Error description
6919 %H - Request domain name
6920 %i - Client IP Address
6922 %o - Message result from external ACL helper
6923 %p - Request Port number
6924 %P - Request Protocol name
6925 %R - Request URL path
6926 %T - Timestamp in RFC 1123 format
6927 %U - Full canonical URL from client
6928 (HTTPS URLs terminate with *)
6929 %u - Full canonical URL from client
6930 %w - Admin email from squid.conf
6932 %% - Literal percent (%) code
6937 OPTIONS INFLUENCING REQUEST FORWARDING
6938 -----------------------------------------------------------------------------
6941 NAME: nonhierarchical_direct
6943 LOC: Config.onoff.nonhierarchical_direct
6946 By default, Squid will send any non-hierarchical requests
6947 (matching hierarchy_stoplist or not cacheable request type) direct
6950 If you set this to off, Squid will prefer to send these
6951 requests to parents.
6953 Note that in most configurations, by turning this off you will only
6954 add latency to these request without any improvement in global hit
6957 If you are inside an firewall see never_direct instead of
6963 LOC: Config.onoff.prefer_direct
6966 Normally Squid tries to use parents for most requests. If you for some
6967 reason like it to first try going direct and only use a parent if
6968 going direct fails set this to on.
6970 By combining nonhierarchical_direct off and prefer_direct on you
6971 can set up Squid to use a parent as a backup path if going direct
6974 Note: If you want Squid to use parents for all requests see
6975 the never_direct directive. prefer_direct only modifies how Squid
6976 acts on cacheable requests.
6981 LOC: Config.accessList.AlwaysDirect
6984 Usage: always_direct allow|deny [!]aclname ...
6986 Here you can use ACL elements to specify requests which should
6987 ALWAYS be forwarded by Squid to the origin servers without using
6988 any peers. For example, to always directly forward requests for
6989 local servers ignoring any parents or siblings you may have use
6992 acl local-servers dstdomain my.domain.net
6993 always_direct allow local-servers
6995 To always forward FTP requests directly, use
6998 always_direct allow FTP
7000 NOTE: There is a similar, but opposite option named
7001 'never_direct'. You need to be aware that "always_direct deny
7002 foo" is NOT the same thing as "never_direct allow foo". You
7003 may need to use a deny rule to exclude a more-specific case of
7004 some other rule. Example:
7006 acl local-external dstdomain external.foo.net
7007 acl local-servers dstdomain .foo.net
7008 always_direct deny local-external
7009 always_direct allow local-servers
7011 NOTE: If your goal is to make the client forward the request
7012 directly to the origin server bypassing Squid then this needs
7013 to be done in the client configuration. Squid configuration
7014 can only tell Squid how Squid should fetch the object.
7016 NOTE: This directive is not related to caching. The replies
7017 is cached as usual even if you use always_direct. To not cache
7018 the replies see the 'cache' directive.
7020 This clause supports both fast and slow acl types.
7021 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7026 LOC: Config.accessList.NeverDirect
7029 Usage: never_direct allow|deny [!]aclname ...
7031 never_direct is the opposite of always_direct. Please read
7032 the description for always_direct if you have not already.
7034 With 'never_direct' you can use ACL elements to specify
7035 requests which should NEVER be forwarded directly to origin
7036 servers. For example, to force the use of a proxy for all
7037 requests, except those in your local domain use something like:
7039 acl local-servers dstdomain .foo.net
7040 never_direct deny local-servers
7041 never_direct allow all
7043 or if Squid is inside a firewall and there are local intranet
7044 servers inside the firewall use something like:
7046 acl local-intranet dstdomain .foo.net
7047 acl local-external dstdomain external.foo.net
7048 always_direct deny local-external
7049 always_direct allow local-intranet
7050 never_direct allow all
7052 This clause supports both fast and slow acl types.
7053 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7057 ADVANCED NETWORKING OPTIONS
7058 -----------------------------------------------------------------------------
7061 NAME: incoming_udp_average incoming_icp_average
7064 LOC: Config.comm_incoming.udp.average
7066 Heavy voodoo here. I can't even believe you are reading this.
7067 Are you crazy? Don't even think about adjusting these unless
7068 you understand the algorithms in comm_select.c first!
7071 NAME: incoming_tcp_average incoming_http_average
7074 LOC: Config.comm_incoming.tcp.average
7076 Heavy voodoo here. I can't even believe you are reading this.
7077 Are you crazy? Don't even think about adjusting these unless
7078 you understand the algorithms in comm_select.c first!
7081 NAME: incoming_dns_average
7084 LOC: Config.comm_incoming.dns.average
7086 Heavy voodoo here. I can't even believe you are reading this.
7087 Are you crazy? Don't even think about adjusting these unless
7088 you understand the algorithms in comm_select.c first!
7091 NAME: min_udp_poll_cnt min_icp_poll_cnt
7094 LOC: Config.comm_incoming.udp.min_poll
7096 Heavy voodoo here. I can't even believe you are reading this.
7097 Are you crazy? Don't even think about adjusting these unless
7098 you understand the algorithms in comm_select.c first!
7101 NAME: min_dns_poll_cnt
7104 LOC: Config.comm_incoming.dns.min_poll
7106 Heavy voodoo here. I can't even believe you are reading this.
7107 Are you crazy? Don't even think about adjusting these unless
7108 you understand the algorithms in comm_select.c first!
7111 NAME: min_tcp_poll_cnt min_http_poll_cnt
7114 LOC: Config.comm_incoming.tcp.min_poll
7116 Heavy voodoo here. I can't even believe you are reading this.
7117 Are you crazy? Don't even think about adjusting these unless
7118 you understand the algorithms in comm_select.c first!
7124 LOC: Config.accept_filter
7128 The name of an accept(2) filter to install on Squid's
7129 listen socket(s). This feature is perhaps specific to
7130 FreeBSD and requires support in the kernel.
7132 The 'httpready' filter delays delivering new connections
7133 to Squid until a full HTTP request has been received.
7134 See the accf_http(9) man page for details.
7136 The 'dataready' filter delays delivering new connections
7137 to Squid until there is some data to process.
7138 See the accf_dataready(9) man page for details.
7142 The 'data' filter delays delivering of new connections
7143 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
7144 You may optionally specify a number of seconds to wait by
7145 'data=N' where N is the number of seconds. Defaults to 30
7146 if not specified. See the tcp(7) man page for details.
7149 accept_filter httpready
7154 NAME: client_ip_max_connections
7156 LOC: Config.client_ip_max_connections
7159 Set an absolute limit on the number of connections a single
7160 client IP can use. Any more than this and Squid will begin to drop
7161 new connections from the client until it closes some links.
7163 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
7164 connections from the client. For finer control use the ACL access controls.
7166 Requires client_db to be enabled (the default).
7168 WARNING: This may noticably slow down traffic received via external proxies
7169 or NAT devices and cause them to rebound error messages back to their clients.
7172 NAME: tcp_recv_bufsize
7176 LOC: Config.tcpRcvBufsz
7178 Size of receive buffer to set for TCP sockets. Probably just
7179 as easy to change your kernel's default. Set to zero to use
7180 the default buffer size.
7185 -----------------------------------------------------------------------------
7192 LOC: Adaptation::Icap::TheConfig.onoff
7195 If you want to enable the ICAP module support, set this to on.
7198 NAME: icap_connect_timeout
7201 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
7204 This parameter specifies how long to wait for the TCP connect to
7205 the requested ICAP server to complete before giving up and either
7206 terminating the HTTP transaction or bypassing the failure.
7208 The default for optional services is peer_connect_timeout.
7209 The default for essential services is connect_timeout.
7210 If this option is explicitly set, its value applies to all services.
7213 NAME: icap_io_timeout
7217 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
7220 This parameter specifies how long to wait for an I/O activity on
7221 an established, active ICAP connection before giving up and
7222 either terminating the HTTP transaction or bypassing the
7225 The default is read_timeout.
7228 NAME: icap_service_failure_limit
7229 COMMENT: limit [in memory-depth time-units]
7230 TYPE: icap_service_failure_limit
7232 LOC: Adaptation::Icap::TheConfig
7235 The limit specifies the number of failures that Squid tolerates
7236 when establishing a new TCP connection with an ICAP service. If
7237 the number of failures exceeds the limit, the ICAP service is
7238 not used for new ICAP requests until it is time to refresh its
7241 A negative value disables the limit. Without the limit, an ICAP
7242 service will not be considered down due to connectivity failures
7243 between ICAP OPTIONS requests.
7245 Squid forgets ICAP service failures older than the specified
7246 value of memory-depth. The memory fading algorithm
7247 is approximate because Squid does not remember individual
7248 errors but groups them instead, splitting the option
7249 value into ten time slots of equal length.
7251 When memory-depth is 0 and by default this option has no
7252 effect on service failure expiration.
7254 Squid always forgets failures when updating service settings
7255 using an ICAP OPTIONS transaction, regardless of this option
7259 # suspend service usage after 10 failures in 5 seconds:
7260 icap_service_failure_limit 10 in 5 seconds
7263 NAME: icap_service_revival_delay
7266 LOC: Adaptation::Icap::TheConfig.service_revival_delay
7269 The delay specifies the number of seconds to wait after an ICAP
7270 OPTIONS request failure before requesting the options again. The
7271 failed ICAP service is considered "down" until fresh OPTIONS are
7274 The actual delay cannot be smaller than the hardcoded minimum
7275 delay of 30 seconds.
7278 NAME: icap_preview_enable
7282 LOC: Adaptation::Icap::TheConfig.preview_enable
7285 The ICAP Preview feature allows the ICAP server to handle the
7286 HTTP message by looking only at the beginning of the message body
7287 or even without receiving the body at all. In some environments,
7288 previews greatly speedup ICAP processing.
7290 During an ICAP OPTIONS transaction, the server may tell Squid what
7291 HTTP messages should be previewed and how big the preview should be.
7292 Squid will not use Preview if the server did not request one.
7294 To disable ICAP Preview for all ICAP services, regardless of
7295 individual ICAP server OPTIONS responses, set this option to "off".
7297 icap_preview_enable off
7300 NAME: icap_preview_size
7303 LOC: Adaptation::Icap::TheConfig.preview_size
7306 The default size of preview data to be sent to the ICAP server.
7307 -1 means no preview. This value might be overwritten on a per server
7308 basis by OPTIONS requests.
7311 NAME: icap_206_enable
7315 LOC: Adaptation::Icap::TheConfig.allow206_enable
7318 206 (Partial Content) responses is an ICAP extension that allows the
7319 ICAP agents to optionally combine adapted and original HTTP message
7320 content. The decision to combine is postponed until the end of the
7321 ICAP response. Squid supports Partial Content extension by default.
7323 Activation of the Partial Content extension is negotiated with each
7324 ICAP service during OPTIONS exchange. Most ICAP servers should handle
7325 negotation correctly even if they do not support the extension, but
7326 some might fail. To disable Partial Content support for all ICAP
7327 services and to avoid any negotiation, set this option to "off".
7333 NAME: icap_default_options_ttl
7336 LOC: Adaptation::Icap::TheConfig.default_options_ttl
7339 The default TTL value for ICAP OPTIONS responses that don't have
7340 an Options-TTL header.
7343 NAME: icap_persistent_connections
7347 LOC: Adaptation::Icap::TheConfig.reuse_connections
7350 Whether or not Squid should use persistent connections to
7354 NAME: adaptation_send_client_ip icap_send_client_ip
7356 IFDEF: USE_ADAPTATION
7358 LOC: Adaptation::Config::send_client_ip
7361 If enabled, Squid shares HTTP client IP information with adaptation
7362 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
7363 For eCAP, Squid sets the libecap::metaClientIp transaction option.
7365 See also: adaptation_uses_indirect_client
7368 NAME: adaptation_send_username icap_send_client_username
7370 IFDEF: USE_ADAPTATION
7372 LOC: Adaptation::Config::send_username
7375 This sends authenticated HTTP client username (if available) to
7376 the adaptation service.
7378 For ICAP, the username value is encoded based on the
7379 icap_client_username_encode option and is sent using the header
7380 specified by the icap_client_username_header option.
7383 NAME: icap_client_username_header
7386 LOC: Adaptation::Icap::TheConfig.client_username_header
7387 DEFAULT: X-Client-Username
7389 ICAP request header name to use for adaptation_send_username.
7392 NAME: icap_client_username_encode
7396 LOC: Adaptation::Icap::TheConfig.client_username_encode
7399 Whether to base64 encode the authenticated client username.
7403 TYPE: icap_service_type
7405 LOC: Adaptation::Icap::TheConfig
7408 Defines a single ICAP service using the following format:
7410 icap_service id vectoring_point uri [option ...]
7413 an opaque identifier or name which is used to direct traffic to
7414 this specific service. Must be unique among all adaptation
7415 services in squid.conf.
7417 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7418 This specifies at which point of transaction processing the
7419 ICAP service should be activated. *_postcache vectoring points
7420 are not yet supported.
7422 uri: icap://servername:port/servicepath
7423 ICAP server and service location.
7425 ICAP does not allow a single service to handle both REQMOD and RESPMOD
7426 transactions. Squid does not enforce that requirement. You can specify
7427 services with the same service_url and different vectoring_points. You
7428 can even specify multiple identical services as long as their
7429 service_names differ.
7432 Service options are separated by white space. ICAP services support
7433 the following name=value options:
7436 If set to 'on' or '1', the ICAP service is treated as
7437 optional. If the service cannot be reached or malfunctions,
7438 Squid will try to ignore any errors and process the message as
7439 if the service was not enabled. No all ICAP errors can be
7440 bypassed. If set to 0, the ICAP service is treated as
7441 essential and all ICAP errors will result in an error page
7442 returned to the HTTP client.
7444 Bypass is off by default: services are treated as essential.
7447 If set to 'on' or '1', the ICAP service is allowed to
7448 dynamically change the current message adaptation plan by
7449 returning a chain of services to be used next. The services
7450 are specified using the X-Next-Services ICAP response header
7451 value, formatted as a comma-separated list of service names.
7452 Each named service should be configured in squid.conf. Other
7453 services are ignored. An empty X-Next-Services value results
7454 in an empty plan which ends the current adaptation.
7456 Dynamic adaptation plan may cross or cover multiple supported
7457 vectoring points in their natural processing order.
7459 Routing is not allowed by default: the ICAP X-Next-Services
7460 response header is ignored.
7463 Only has effect on split-stack systems. The default on those systems
7464 is to use IPv4-only connections. When set to 'on' this option will
7465 make Squid use IPv6-only connections to contact this ICAP service.
7467 on-overload=block|bypass|wait|force
7468 If the service Max-Connections limit has been reached, do
7469 one of the following for each new ICAP transaction:
7470 * block: send an HTTP error response to the client
7471 * bypass: ignore the "over-connected" ICAP service
7472 * wait: wait (in a FIFO queue) for an ICAP connection slot
7473 * force: proceed, ignoring the Max-Connections limit
7475 In SMP mode with N workers, each worker assumes the service
7476 connection limit is Max-Connections/N, even though not all
7477 workers may use a given service.
7479 The default value is "bypass" if service is bypassable,
7480 otherwise it is set to "wait".
7484 Use the given number as the Max-Connections limit, regardless
7485 of the Max-Connections value given by the service, if any.
7487 Older icap_service format without optional named parameters is
7488 deprecated but supported for backward compatibility.
7491 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
7492 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
7496 TYPE: icap_class_type
7501 This deprecated option was documented to define an ICAP service
7502 chain, even though it actually defined a set of similar, redundant
7503 services, and the chains were not supported.
7505 To define a set of redundant services, please use the
7506 adaptation_service_set directive. For service chains, use
7507 adaptation_service_chain.
7511 TYPE: icap_access_type
7516 This option is deprecated. Please use adaptation_access, which
7517 has the same ICAP functionality, but comes with better
7518 documentation, and eCAP support.
7523 -----------------------------------------------------------------------------
7530 LOC: Adaptation::Ecap::TheConfig.onoff
7533 Controls whether eCAP support is enabled.
7537 TYPE: ecap_service_type
7539 LOC: Adaptation::Ecap::TheConfig
7542 Defines a single eCAP service
7544 ecap_service id vectoring_point uri [option ...]
7547 an opaque identifier or name which is used to direct traffic to
7548 this specific service. Must be unique among all adaptation
7549 services in squid.conf.
7551 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7552 This specifies at which point of transaction processing the
7553 eCAP service should be activated. *_postcache vectoring points
7554 are not yet supported.
7556 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
7557 Squid uses the eCAP service URI to match this configuration
7558 line with one of the dynamically loaded services. Each loaded
7559 eCAP service must have a unique URI. Obtain the right URI from
7560 the service provider.
7563 Service options are separated by white space. eCAP services support
7564 the following name=value options:
7567 If set to 'on' or '1', the eCAP service is treated as optional.
7568 If the service cannot be reached or malfunctions, Squid will try
7569 to ignore any errors and process the message as if the service
7570 was not enabled. No all eCAP errors can be bypassed.
7571 If set to 'off' or '0', the eCAP service is treated as essential
7572 and all eCAP errors will result in an error page returned to the
7575 Bypass is off by default: services are treated as essential.
7578 If set to 'on' or '1', the eCAP service is allowed to
7579 dynamically change the current message adaptation plan by
7580 returning a chain of services to be used next.
7582 Dynamic adaptation plan may cross or cover multiple supported
7583 vectoring points in their natural processing order.
7585 Routing is not allowed by default.
7587 Older ecap_service format without optional named parameters is
7588 deprecated but supported for backward compatibility.
7592 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
7593 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
7596 NAME: loadable_modules
7598 IFDEF: USE_LOADABLE_MODULES
7599 LOC: Config.loadable_module_names
7602 Instructs Squid to load the specified dynamic module(s) or activate
7603 preloaded module(s).
7605 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
7609 MESSAGE ADAPTATION OPTIONS
7610 -----------------------------------------------------------------------------
7613 NAME: adaptation_service_set
7614 TYPE: adaptation_service_set_type
7615 IFDEF: USE_ADAPTATION
7620 Configures an ordered set of similar, redundant services. This is
7621 useful when hot standby or backup adaptation servers are available.
7623 adaptation_service_set set_name service_name1 service_name2 ...
7625 The named services are used in the set declaration order. The first
7626 applicable adaptation service from the set is used first. The next
7627 applicable service is tried if and only if the transaction with the
7628 previous service fails and the message waiting to be adapted is still
7631 When adaptation starts, broken services are ignored as if they were
7632 not a part of the set. A broken service is a down optional service.
7634 The services in a set must be attached to the same vectoring point
7635 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7637 If all services in a set are optional then adaptation failures are
7638 bypassable. If all services in the set are essential, then a
7639 transaction failure with one service may still be retried using
7640 another service from the set, but when all services fail, the master
7641 transaction fails as well.
7643 A set may contain a mix of optional and essential services, but that
7644 is likely to lead to surprising results because broken services become
7645 ignored (see above), making previously bypassable failures fatal.
7646 Technically, it is the bypassability of the last failed service that
7649 See also: adaptation_access adaptation_service_chain
7652 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
7653 adaptation service_set svcLogger loggerLocal loggerRemote
7656 NAME: adaptation_service_chain
7657 TYPE: adaptation_service_chain_type
7658 IFDEF: USE_ADAPTATION
7663 Configures a list of complementary services that will be applied
7664 one-by-one, forming an adaptation chain or pipeline. This is useful
7665 when Squid must perform different adaptations on the same message.
7667 adaptation_service_chain chain_name service_name1 svc_name2 ...
7669 The named services are used in the chain declaration order. The first
7670 applicable adaptation service from the chain is used first. The next
7671 applicable service is applied to the successful adaptation results of
7672 the previous service in the chain.
7674 When adaptation starts, broken services are ignored as if they were
7675 not a part of the chain. A broken service is a down optional service.
7677 Request satisfaction terminates the adaptation chain because Squid
7678 does not currently allow declaration of RESPMOD services at the
7679 "reqmod_precache" vectoring point (see icap_service or ecap_service).
7681 The services in a chain must be attached to the same vectoring point
7682 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7684 A chain may contain a mix of optional and essential services. If an
7685 essential adaptation fails (or the failure cannot be bypassed for
7686 other reasons), the master transaction fails. Otherwise, the failure
7687 is bypassed as if the failed adaptation service was not in the chain.
7689 See also: adaptation_access adaptation_service_set
7692 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
7695 NAME: adaptation_access
7696 TYPE: adaptation_access_type
7697 IFDEF: USE_ADAPTATION
7701 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
7703 adaptation_access service_name allow|deny [!]aclname...
7704 adaptation_access set_name allow|deny [!]aclname...
7706 At each supported vectoring point, the adaptation_access
7707 statements are processed in the order they appear in this
7708 configuration file. Statements pointing to the following services
7709 are ignored (i.e., skipped without checking their ACL):
7711 - services serving different vectoring points
7712 - "broken-but-bypassable" services
7713 - "up" services configured to ignore such transactions
7714 (e.g., based on the ICAP Transfer-Ignore header).
7716 When a set_name is used, all services in the set are checked
7717 using the same rules, to find the first applicable one. See
7718 adaptation_service_set for details.
7720 If an access list is checked and there is a match, the
7721 processing stops: For an "allow" rule, the corresponding
7722 adaptation service is used for the transaction. For a "deny"
7723 rule, no adaptation service is activated.
7725 It is currently not possible to apply more than one adaptation
7726 service at the same vectoring point to the same HTTP transaction.
7728 See also: icap_service and ecap_service
7731 adaptation_access service_1 allow all
7734 NAME: adaptation_service_iteration_limit
7736 IFDEF: USE_ADAPTATION
7737 LOC: Adaptation::Config::service_iteration_limit
7740 Limits the number of iterations allowed when applying adaptation
7741 services to a message. If your longest adaptation set or chain
7742 may have more than 16 services, increase the limit beyond its
7743 default value of 16. If detecting infinite iteration loops sooner
7744 is critical, make the iteration limit match the actual number
7745 of services in your longest adaptation set or chain.
7747 Infinite adaptation loops are most likely with routing services.
7749 See also: icap_service routing=1
7752 NAME: adaptation_masterx_shared_names
7754 IFDEF: USE_ADAPTATION
7755 LOC: Adaptation::Config::masterx_shared_name
7758 For each master transaction (i.e., the HTTP request and response
7759 sequence, including all related ICAP and eCAP exchanges), Squid
7760 maintains a table of metadata. The table entries are (name, value)
7761 pairs shared among eCAP and ICAP exchanges. The table is destroyed
7762 with the master transaction.
7764 This option specifies the table entry names that Squid must accept
7765 from and forward to the adaptation transactions.
7767 An ICAP REQMOD or RESPMOD transaction may set an entry in the
7768 shared table by returning an ICAP header field with a name
7769 specified in adaptation_masterx_shared_names.
7771 An eCAP REQMOD or RESPMOD transaction may set an entry in the
7772 shared table by implementing the libecap::visitEachOption() API
7773 to provide an option with a name specified in
7774 adaptation_masterx_shared_names.
7776 Squid will store and forward the set entry to subsequent adaptation
7777 transactions within the same master transaction scope.
7779 Only one shared entry name is supported at this time.
7782 # share authentication information among ICAP services
7783 adaptation_masterx_shared_names X-Subscriber-ID
7786 NAME: adaptation_meta
7788 IFDEF: USE_ADAPTATION
7789 LOC: Adaptation::Config::metaHeaders
7792 This option allows Squid administrator to add custom ICAP request
7793 headers or eCAP options to Squid ICAP requests or eCAP transactions.
7794 Use it to pass custom authentication tokens and other
7795 transaction-state related meta information to an ICAP/eCAP service.
7797 The addition of a meta header is ACL-driven:
7798 adaptation_meta name value [!]aclname ...
7800 Processing for a given header name stops after the first ACL list match.
7801 Thus, it is impossible to add two headers with the same name. If no ACL
7802 lists match for a given header name, no such header is added. For
7805 # do not debug transactions except for those that need debugging
7806 adaptation_meta X-Debug 1 needs_debugging
7808 # log all transactions except for those that must remain secret
7809 adaptation_meta X-Log 1 !keep_secret
7811 # mark transactions from users in the "G 1" group
7812 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
7814 The "value" parameter may be a regular squid.conf token or a "double
7815 quoted string". Within the quoted string, use backslash (\) to escape
7816 any character, which is currently only useful for escaping backslashes
7817 and double quotes. For example,
7818 "this string has one backslash (\\) and two \"quotes\""
7820 Used adaptation_meta header values may be logged via %note
7821 logformat code. If multiple adaptation_meta headers with the same name
7822 are used during master transaction lifetime, the header values are
7823 logged in the order they were used and duplicate values are ignored
7824 (only the first repeated value will be logged).
7830 LOC: Adaptation::Icap::TheConfig.repeat
7831 DEFAULT_IF_NONE: deny all
7833 This ACL determines which retriable ICAP transactions are
7834 retried. Transactions that received a complete ICAP response
7835 and did not have to consume or produce HTTP bodies to receive
7836 that response are usually retriable.
7838 icap_retry allow|deny [!]aclname ...
7840 Squid automatically retries some ICAP I/O timeouts and errors
7841 due to persistent connection race conditions.
7843 See also: icap_retry_limit
7846 NAME: icap_retry_limit
7849 LOC: Adaptation::Icap::TheConfig.repeat_limit
7852 Limits the number of retries allowed. When set to zero (default),
7853 no retries are allowed.
7855 Communication errors due to persistent connection race
7856 conditions are unavoidable, automatically retried, and do not
7857 count against this limit.
7859 See also: icap_retry
7865 -----------------------------------------------------------------------------
7868 NAME: check_hostnames
7871 LOC: Config.onoff.check_hostnames
7873 For security and stability reasons Squid can check
7874 hostnames for Internet standard RFC compliance. If you want
7875 Squid to perform these checks turn this directive on.
7878 NAME: allow_underscore
7881 LOC: Config.onoff.allow_underscore
7883 Underscore characters is not strictly allowed in Internet hostnames
7884 but nevertheless used by many sites. Set this to off if you want
7885 Squid to be strict about the standard.
7886 This check is performed only when check_hostnames is set to on.
7889 NAME: cache_dns_program
7891 IFDEF: USE_DNSHELPER
7892 DEFAULT: @DEFAULT_DNSSERVER@
7893 LOC: Config.Program.dnsserver
7895 Specify the location of the executable for dnslookup process.
7899 TYPE: HelperChildConfig
7900 IFDEF: USE_DNSHELPER
7901 DEFAULT: 32 startup=1 idle=1
7902 LOC: Config.dnsChildren
7904 The maximum number of processes spawn to service DNS name lookups.
7905 If you limit it too few Squid will have to wait for them to process
7906 a backlog of requests, slowing it down. If you allow too many they
7907 will use RAM and other system resources noticably.
7908 The maximum this may be safely set to is 32.
7910 The startup= and idle= options allow some measure of skew in your
7915 Sets a minimum of how many processes are to be spawned when Squid
7916 starts or reconfigures. When set to zero the first request will
7917 cause spawning of the first child process to handle it.
7919 Starting too few will cause an initial slowdown in traffic as Squid
7920 attempts to simultaneously spawn enough processes to cope.
7924 Sets a minimum of how many processes Squid is to try and keep available
7925 at all times. When traffic begins to rise above what the existing
7926 processes can handle this many more will be spawned up to the maximum
7927 configured. A minimum setting of 1 is required.
7930 NAME: dns_retransmit_interval
7933 LOC: Config.Timeout.idns_retransmit
7934 IFDEF: !USE_DNSHELPER
7936 Initial retransmit interval for DNS queries. The interval is
7937 doubled each time all configured DNS servers have been tried.
7943 LOC: Config.Timeout.idns_query
7944 IFDEF: !USE_DNSHELPER
7946 DNS Query timeout. If no response is received to a DNS query
7947 within this time all DNS servers for the queried domain
7948 are assumed to be unavailable.
7951 NAME: dns_packet_max
7954 LOC: Config.dns.packet_max
7955 IFDEF: !USE_DNSHELPER
7957 Maximum number of bytes packet size to advertise via EDNS.
7958 Set to "none" to disable EDNS large packet support.
7960 For legacy reasons DNS UDP replies will default to 512 bytes which
7961 is too small for many responses. EDNS provides a means for Squid to
7962 negotiate receiving larger responses back immediately without having
7963 to failover with repeat requests. Responses larger than this limit
7964 will retain the old behaviour of failover to TCP DNS.
7966 Squid has no real fixed limit internally, but allowing packet sizes
7967 over 1500 bytes requires network jumbogram support and is usually not
7970 WARNING: The RFC also indicates that some older resolvers will reply
7971 with failure of the whole request if the extension is added. Some
7972 resolvers have already been identified which will reply with mangled
7973 EDNS response on occasion. Usually in response to many-KB jumbogram
7974 sizes being advertised by Squid.
7975 Squid will currently treat these both as an unable-to-resolve domain
7976 even if it would be resolvable without EDNS.
7983 LOC: Config.onoff.res_defnames
7985 Normally the RES_DEFNAMES resolver option is disabled
7986 (see res_init(3)). This prevents caches in a hierarchy
7987 from interpreting single-component hostnames locally. To allow
7988 Squid to handle single-component names, enable this option.
7991 NAME: dns_nameservers
7994 LOC: Config.dns_nameservers
7996 Use this if you want to specify a list of DNS name servers
7997 (IP addresses) to use instead of those given in your
7998 /etc/resolv.conf file.
7999 On Windows platforms, if no value is specified here or in
8000 the /etc/resolv.conf file, the list of DNS name servers are
8001 taken from the Windows registry, both static and dynamic DHCP
8002 configurations are supported.
8004 Example: dns_nameservers 10.0.0.1 192.172.0.4
8009 DEFAULT: @DEFAULT_HOSTS@
8010 LOC: Config.etcHostsPath
8012 Location of the host-local IP name-address associations
8013 database. Most Operating Systems have such a file on different
8015 - Un*X & Linux: /etc/hosts
8016 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
8017 (%SystemRoot% value install default is c:\winnt)
8018 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
8019 (%SystemRoot% value install default is c:\windows)
8020 - Windows 9x/Me: %windir%\hosts
8021 (%windir% value is usually c:\windows)
8022 - Cygwin: /etc/hosts
8024 The file contains newline-separated definitions, in the
8025 form ip_address_in_dotted_form name [name ...] names are
8026 whitespace-separated. Lines beginning with an hash (#)
8027 character are comments.
8029 The file is checked at startup and upon configuration.
8030 If set to 'none', it won't be checked.
8031 If append_domain is used, that domain will be added to
8032 domain-local (i.e. not containing any dot character) host
8038 LOC: Config.appendDomain
8041 Appends local domain name to hostnames without any dots in
8042 them. append_domain must begin with a period.
8044 Be warned there are now Internet names with no dots in
8045 them using only top-domain names, so setting this may
8046 cause some Internet sites to become unavailable.
8049 append_domain .yourdomain.com
8052 NAME: ignore_unknown_nameservers
8054 LOC: Config.onoff.ignore_unknown_nameservers
8056 IFDEF: !USE_DNSHELPER
8058 By default Squid checks that DNS responses are received
8059 from the same IP addresses they are sent to. If they
8060 don't match, Squid ignores the response and writes a warning
8061 message to cache.log. You can allow responses from unknown
8062 nameservers by setting this option to 'off'.
8068 LOC: Config.dns.v4_first
8069 IFDEF: !USE_DNSHELPER
8071 With the IPv6 Internet being as fast or faster than IPv4 Internet
8072 for most networks Squid prefers to contact websites over IPv6.
8074 This option reverses the order of preference to make Squid contact
8075 dual-stack websites over IPv4 first. Squid will still perform both
8076 IPv6 and IPv4 DNS lookups before connecting.
8079 This option will restrict the situations under which IPv6
8080 connectivity is used (and tested). Hiding network problems
8081 which would otherwise be detected and warned about.
8085 COMMENT: (number of entries)
8088 LOC: Config.ipcache.size
8095 LOC: Config.ipcache.low
8102 LOC: Config.ipcache.high
8104 The size, low-, and high-water marks for the IP cache.
8107 NAME: fqdncache_size
8108 COMMENT: (number of entries)
8111 LOC: Config.fqdncache.size
8113 Maximum number of FQDN cache entries.
8118 -----------------------------------------------------------------------------
8125 LOC: Config.onoff.mem_pools
8127 If set, Squid will keep pools of allocated (but unused) memory
8128 available for future use. If memory is a premium on your
8129 system and you believe your malloc library outperforms Squid
8130 routines, disable this.
8133 NAME: memory_pools_limit
8137 LOC: Config.MemPools.limit
8139 Used only with memory_pools on:
8140 memory_pools_limit 50 MB
8142 If set to a non-zero value, Squid will keep at most the specified
8143 limit of allocated (but unused) memory in memory pools. All free()
8144 requests that exceed this limit will be handled by your malloc
8145 library. Squid does not pre-allocate any memory, just safe-keeps
8146 objects that otherwise would be free()d. Thus, it is safe to set
8147 memory_pools_limit to a reasonably high value even if your
8148 configuration will use less memory.
8150 If set to none, Squid will keep all memory it can. That is, there
8151 will be no limit on the total amount of memory used for safe-keeping.
8153 To disable memory allocation optimization, do not set
8154 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
8156 An overhead for maintaining memory pools is not taken into account
8157 when the limit is checked. This overhead is close to four bytes per
8158 object kept. However, pools may actually _save_ memory because of
8159 reduced memory thrashing in your malloc library.
8163 COMMENT: on|off|transparent|truncate|delete
8166 LOC: opt_forwarded_for
8168 If set to "on", Squid will append your client's IP address
8169 in the HTTP requests it forwards. By default it looks like:
8171 X-Forwarded-For: 192.1.2.3
8173 If set to "off", it will appear as
8175 X-Forwarded-For: unknown
8177 If set to "transparent", Squid will not alter the
8178 X-Forwarded-For header in any way.
8180 If set to "delete", Squid will delete the entire
8181 X-Forwarded-For header.
8183 If set to "truncate", Squid will remove all existing
8184 X-Forwarded-For entries, and place the client IP as the sole entry.
8187 NAME: cachemgr_passwd
8188 TYPE: cachemgrpasswd
8190 LOC: Config.passwd_list
8192 Specify passwords for cachemgr operations.
8194 Usage: cachemgr_passwd password action action ...
8196 Some valid actions are (see cache manager menu for a full list):
8236 * Indicates actions which will not be performed without a
8237 valid password, others can be performed if not listed here.
8239 To disable an action, set the password to "disable".
8240 To allow performing an action without a password, set the
8243 Use the keyword "all" to set the same password for all actions.
8246 cachemgr_passwd secret shutdown
8247 cachemgr_passwd lesssssssecret info stats/objects
8248 cachemgr_passwd disable all
8255 LOC: Config.onoff.client_db
8257 If you want to disable collecting per-client statistics,
8258 turn off client_db here.
8261 NAME: refresh_all_ims
8265 LOC: Config.onoff.refresh_all_ims
8267 When you enable this option, squid will always check
8268 the origin server for an update when a client sends an
8269 If-Modified-Since request. Many browsers use IMS
8270 requests when the user requests a reload, and this
8271 ensures those clients receive the latest version.
8273 By default (off), squid may return a Not Modified response
8274 based on the age of the cached version.
8277 NAME: reload_into_ims
8278 IFDEF: USE_HTTP_VIOLATIONS
8282 LOC: Config.onoff.reload_into_ims
8284 When you enable this option, client no-cache or ``reload''
8285 requests will be changed to If-Modified-Since requests.
8286 Doing this VIOLATES the HTTP standard. Enabling this
8287 feature could make you liable for problems which it
8290 see also refresh_pattern for a more selective approach.
8293 NAME: connect_retries
8295 LOC: Config.connect_retries
8298 This sets the maximum number of connection attempts made for each
8299 TCP connection. The connect_retries attempts must all still
8300 complete within the connection timeout period.
8302 The default is not to re-try if the first connection attempt fails.
8303 The (not recommended) maximum is 10 tries.
8305 A warning message will be generated if it is set to a too-high
8306 value and the configured value will be over-ridden.
8308 Note: These re-tries are in addition to forward_max_tries
8309 which limit how many different addresses may be tried to find
8313 NAME: retry_on_error
8315 LOC: Config.retry.onerror
8318 If set to ON Squid will automatically retry requests when
8319 receiving an error response with status 403 (Forbidden),
8320 500 (Internal Error), 501 or 503 (Service not available).
8321 Status 502 and 504 (Gateway errors) are always retried.
8323 This is mainly useful if you are in a complex cache hierarchy to
8324 work around access control errors.
8326 NOTE: This retry will attempt to find another working destination.
8327 Which is different from the server which just failed.
8330 NAME: as_whois_server
8332 LOC: Config.as_whois_server
8333 DEFAULT: whois.ra.net
8335 WHOIS server to query for AS numbers. NOTE: AS numbers are
8336 queried only when Squid starts up, not for every request.
8341 LOC: Config.onoff.offline
8344 Enable this option and Squid will never try to validate cached
8348 NAME: uri_whitespace
8349 TYPE: uri_whitespace
8350 LOC: Config.uri_whitespace
8353 What to do with requests that have whitespace characters in the
8356 strip: The whitespace characters are stripped out of the URL.
8357 This is the behavior recommended by RFC2396.
8358 deny: The request is denied. The user receives an "Invalid
8360 allow: The request is allowed and the URI is not changed. The
8361 whitespace characters remain in the URI. Note the
8362 whitespace is passed to redirector processes if they
8364 encode: The request is allowed and the whitespace characters are
8365 encoded according to RFC1738. This could be considered
8366 a violation of the HTTP/1.1
8367 RFC because proxies are not allowed to rewrite URI's.
8368 chop: The request is allowed and the URI is chopped at the
8369 first whitespace. This might also be considered a
8375 LOC: Config.chroot_dir
8378 Specifies a directory where Squid should do a chroot() while
8379 initializing. This also causes Squid to fully drop root
8380 privileges after initializing. This means, for example, if you
8381 use a HTTP port less than 1024 and try to reconfigure, you may
8382 get an error saying that Squid can not open the port.
8385 NAME: balance_on_multiple_ip
8387 LOC: Config.onoff.balance_on_multiple_ip
8390 Modern IP resolvers in squid sort lookup results by preferred access.
8391 By default squid will use these IP in order and only rotates to
8392 the next listed when the most preffered fails.
8394 Some load balancing servers based on round robin DNS have been
8395 found not to preserve user session state across requests
8396 to different IP addresses.
8398 Enabling this directive Squid rotates IP's per request.
8401 NAME: pipeline_prefetch
8403 LOC: Config.onoff.pipeline_prefetch
8406 To boost the performance of pipelined requests to closer
8407 match that of a non-proxied environment Squid can try to fetch
8408 up to two requests in parallel from a pipeline.
8410 Defaults to off for bandwidth management and access logging
8413 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
8416 NAME: high_response_time_warning
8419 LOC: Config.warnings.high_rptm
8422 If the one-minute median response time exceeds this value,
8423 Squid prints a WARNING with debug level 0 to get the
8424 administrators attention. The value is in milliseconds.
8427 NAME: high_page_fault_warning
8429 LOC: Config.warnings.high_pf
8432 If the one-minute average page fault rate exceeds this
8433 value, Squid prints a WARNING with debug level 0 to get
8434 the administrators attention. The value is in page faults
8438 NAME: high_memory_warning
8440 LOC: Config.warnings.high_memory
8443 If the memory usage (as determined by mallinfo) exceeds
8444 this amount, Squid prints a WARNING with debug level 0 to get
8445 the administrators attention.
8448 NAME: sleep_after_fork
8449 COMMENT: (microseconds)
8451 LOC: Config.sleep_after_fork
8454 When this is set to a non-zero value, the main Squid process
8455 sleeps the specified number of microseconds after a fork()
8456 system call. This sleep may help the situation where your
8457 system reports fork() failures due to lack of (virtual)
8458 memory. Note, however, if you have a lot of child
8459 processes, these sleep delays will add up and your
8460 Squid will not service requests for some amount of time
8461 until all the child processes have been started.
8462 On Windows value less then 1000 (1 milliseconds) are
8466 NAME: windows_ipaddrchangemonitor
8467 IFDEF: _SQUID_WINDOWS_
8471 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
8473 On Windows Squid by default will monitor IP address changes and will
8474 reconfigure itself after any detected event. This is very useful for
8475 proxies connected to internet with dial-up interfaces.
8476 In some cases (a Proxy server acting as VPN gateway is one) it could be
8477 desiderable to disable this behaviour setting this to 'off'.
8478 Note: after changing this, Squid service must be restarted.
8483 IFDEF: USE_SQUID_EUI
8485 LOC: Eui::TheConfig.euiLookup
8487 Whether to lookup the EUI or MAC address of a connected client.
8490 NAME: max_filedescriptors max_filedesc
8493 LOC: Config.max_filedescriptors
8495 The maximum number of filedescriptors supported.
8497 The default "0" means Squid inherits the current ulimit setting.
8499 Note: Changing this requires a restart of Squid. Also
8500 not all comm loops supports large values.
8508 Number of main Squid processes or "workers" to fork and maintain.
8509 0: "no daemon" mode, like running "squid -N ..."
8510 1: "no SMP" mode, start one main Squid process daemon (default)
8511 N: start N main Squid process daemons (i.e., SMP mode)
8513 In SMP mode, each worker does nearly all what a single Squid daemon
8514 does (e.g., listen on http_port and forward HTTP requests).
8517 NAME: cpu_affinity_map
8518 TYPE: CpuAffinityMap
8519 LOC: Config.cpuAffinityMap
8522 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
8524 Sets 1:1 mapping between Squid processes and CPU cores. For example,
8526 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
8528 affects processes 1 through 4 only and places them on the first
8529 four even cores, starting with core #1.
8531 CPU cores are numbered starting from 1. Requires support for
8532 sched_getaffinity(2) and sched_setaffinity(2) system calls.
8534 Multiple cpu_affinity_map options are merged.
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