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 Removed in 3.2
108 NAME: ignore_expect_100
111 Remove this line. The HTTP/1.1 feature is now fully supported by default.
114 NAME: dns_v4_fallback
123 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
126 NAME: url_rewrite_concurrency
129 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
132 # Options Removed in 3.1
136 Remove this line. DNS is no longer tested on startup.
139 NAME: extension_methods
142 Remove this line. All valid methods for HTTP are accepted by default.
145 # 2.7 Options Removed/Replaced in 3.1
153 Remove this line. HTTP/1.1 is supported by default.
156 NAME: upgrade_http0.9
159 Remove this line. ICY/1.0 streaming protocol is supported by default.
162 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
165 Alter these entries. Use the qos_flows directive instead.
168 # Options Removed in 3.0
172 Since squid-3.0 replace with request_header_access or reply_header_access
173 depending on whether you wish to match client requests or server replies.
176 NAME: httpd_accel_no_pmtu_disc
179 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
183 OPTIONS FOR AUTHENTICATION
184 -----------------------------------------------------------------------------
193 This is used to define parameters for the various authentication
194 schemes supported by Squid.
196 format: auth_param scheme parameter [setting]
198 The order in which authentication schemes are presented to the client is
199 dependent on the order the scheme first appears in config file. IE
200 has a bug (it's not RFC 2617 compliant) in that it will use the basic
201 scheme if basic is the first entry presented, even if more secure
202 schemes are presented. For now use the order in the recommended
203 settings section below. If other browsers have difficulties (don't
204 recognize the schemes offered even if you are using basic) either
205 put basic first, or disable the other schemes (by commenting out their
208 Once an authentication scheme is fully configured, it can only be
209 shutdown by shutting squid down and restarting. Changes can be made on
210 the fly and activated with a reconfigure. I.E. You can change to a
211 different helper, but not unconfigure the helper completely.
213 Please note that while this directive defines how Squid processes
214 authentication it does not automatically activate authentication.
215 To use authentication you must in addition make use of ACLs based
216 on login name in http_access (proxy_auth, proxy_auth_regex or
217 external with %LOGIN used in the format tag). The browser will be
218 challenged for authentication on the first such acl encountered
219 in http_access processing and will also be re-challenged for new
220 login credentials if the request is being denied by a proxy_auth
223 WARNING: authentication can't be used in a transparently intercepting
224 proxy as the client then thinks it is talking to an origin server and
225 not the proxy. This is a limitation of bending the TCP/IP protocol to
226 transparently intercepting port 80, not a limitation in Squid.
227 Ports flagged 'transparent', 'intercept', or 'tproxy' have
228 authentication disabled.
230 === Parameters for the basic scheme follow. ===
233 Specify the command for the external authenticator. Such a program
234 reads a line containing "username password" and replies "OK" or
235 "ERR" in an endless loop. "ERR" responses may optionally be followed
236 by a error description available as %m in the returned error page.
237 If you use an authenticator, make sure you have 1 acl of type
240 By default, the basic authentication scheme is not used unless a
241 program is specified.
243 If you want to use the traditional NCSA proxy authentication, set
244 this line to something like
246 auth_param basic program @DEFAULT_PREFIX@/libexec/ncsa_auth @DEFAULT_PREFIX@/etc/passwd
249 HTTP uses iso-latin-1 as characterset, while some authentication
250 backends such as LDAP expects UTF-8. If this is set to on Squid will
251 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
252 username & password to the helper.
254 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
255 The maximum number of authenticator processes to spawn. If you start too few
256 Squid will have to wait for them to process a backlog of credential
257 verifications, slowing it down. When password verifications are
258 done via a (slow) network you are likely to need lots of
259 authenticator processes.
261 The startup= and idle= options permit some skew in the exact amount
262 run. A minimum of startup=N will begin during startup and reconfigure.
263 Squid will start more in groups of up to idle=N in an attempt to meet
264 traffic needs and to keep idle=N free above those traffic needs up to
267 The concurrency= option sets the number of concurrent requests the
268 helper can process. The default of 0 is used for helpers who only
269 supports one request at a time. Setting this to a number greater than
270 0 changes the protocol used to include a channel number first on the
271 request/response line, allowing multiple requests to be sent to the
272 same helper in parallell without wating for the response.
273 Must not be set unless it's known the helper supports this.
275 auth_param basic children 20 startup=0 idle=1
278 Specifies the realm name which is to be reported to the
279 client for the basic proxy authentication scheme (part of
280 the text the user will see when prompted their username and
281 password). There is no default.
282 auth_param basic realm Squid proxy-caching web server
284 "credentialsttl" timetolive
285 Specifies how long squid assumes an externally validated
286 username:password pair is valid for - in other words how
287 often the helper program is called for that user. Set this
288 low to force revalidation with short lived passwords. Note
289 setting this high does not impact your susceptibility
290 to replay attacks unless you are using an one-time password
291 system (such as SecureID). If you are using such a system,
292 you will be vulnerable to replay attacks unless you also
293 use the max_user_ip ACL in an http_access rule.
295 "casesensitive" on|off
296 Specifies if usernames are case sensitive. Most user databases are
297 case insensitive allowing the same username to be spelled using both
298 lower and upper case letters, but some are case sensitive. This
299 makes a big difference for user_max_ip ACL processing and similar.
300 auth_param basic casesensitive off
302 === Parameters for the digest scheme follow ===
305 Specify the command for the external authenticator. Such
306 a program reads a line containing "username":"realm" and
307 replies with the appropriate H(A1) value hex encoded or
308 ERR if the user (or his H(A1) hash) does not exists.
309 See rfc 2616 for the definition of H(A1).
310 "ERR" responses may optionally be followed by a error description
311 available as %m in the returned error page.
313 By default, the digest authentication scheme is not used unless a
314 program is specified.
316 If you want to use a digest authenticator, set this line to
319 auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass
322 HTTP uses iso-latin-1 as characterset, while some authentication
323 backends such as LDAP expects UTF-8. If this is set to on Squid will
324 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
325 username & password to the helper.
327 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
328 The maximum number of authenticator processes to spawn (default 5).
329 If you start too few Squid will have to wait for them to
330 process a backlog of H(A1) calculations, slowing it down.
331 When the H(A1) calculations are done via a (slow) network
332 you are likely to need lots of authenticator processes.
334 The startup= and idle= options permit some skew in the exact amount
335 run. A minimum of startup=N will begin during startup and reconfigure.
336 Squid will start more in groups of up to idle=N in an attempt to meet
337 traffic needs and to keep idle=N free above those traffic needs up to
340 The concurrency= option sets the number of concurrent requests the
341 helper can process. The default of 0 is used for helpers who only
342 supports one request at a time. Setting this to a number greater than
343 0 changes the protocol used to include a channel number first on the
344 request/response line, allowing multiple requests to be sent to the
345 same helper in parallell without wating for the response.
346 Must not be set unless it's known the helper supports this.
348 auth_param digest children 20 startup=0 idle=1
351 Specifies the realm name which is to be reported to the
352 client for the digest proxy authentication scheme (part of
353 the text the user will see when prompted their username and
354 password). There is no default.
355 auth_param digest realm Squid proxy-caching web server
357 "nonce_garbage_interval" timeinterval
358 Specifies the interval that nonces that have been issued
359 to client_agent's are checked for validity.
361 "nonce_max_duration" timeinterval
362 Specifies the maximum length of time a given nonce will be
365 "nonce_max_count" number
366 Specifies the maximum number of times a given nonce can be
369 "nonce_strictness" on|off
370 Determines if squid requires strict increment-by-1 behavior
371 for nonce counts, or just incrementing (off - for use when
372 useragents generate nonce counts that occasionally miss 1
373 (ie, 1,2,4,6)). Default off.
375 "check_nonce_count" on|off
376 This directive if set to off can disable the nonce count check
377 completely to work around buggy digest qop implementations in
378 certain mainstream browser versions. Default on to check the
379 nonce count to protect from authentication replay attacks.
381 "post_workaround" on|off
382 This is a workaround to certain buggy browsers who sends
383 an incorrect request digest in POST requests when reusing
384 the same nonce as acquired earlier on a GET request.
386 === NTLM scheme options follow ===
389 Specify the command for the external NTLM authenticator.
390 Such a program reads exchanged NTLMSSP packets with
391 the browser via Squid until authentication is completed.
392 If you use an NTLM authenticator, make sure you have 1 acl
393 of type proxy_auth. By default, the NTLM authenticator_program
396 auth_param ntlm program @DEFAULT_PREFIX@/bin/ntlm_auth
398 "children" numberofchildren [startup=N] [idle=N]
399 The maximum number of authenticator processes to spawn (default 5).
400 If you start too few Squid will have to wait for them to
401 process a backlog of credential verifications, slowing it
402 down. When credential verifications are done via a (slow)
403 network you are likely to need lots of authenticator
406 The startup= and idle= options permit some skew in the exact amount
407 run. A minimum of startup=N will begin during startup and reconfigure.
408 Squid will start more in groups of up to idle=N in an attempt to meet
409 traffic needs and to keep idle=N free above those traffic needs up to
412 auth_param ntlm children 20 startup=0 idle=1
415 If you experience problems with PUT/POST requests when using the
416 Negotiate authentication scheme then you can try setting this to
417 off. This will cause Squid to forcibly close the connection on
418 the initial requests where the browser asks which schemes are
419 supported by the proxy.
421 auth_param ntlm keep_alive on
423 === Options for configuring the NEGOTIATE auth-scheme follow ===
426 Specify the command for the external Negotiate authenticator.
427 This protocol is used in Microsoft Active-Directory enabled setups with
428 the Microsoft Internet Explorer or Mozilla Firefox browsers.
429 Its main purpose is to exchange credentials with the Squid proxy
430 using the Kerberos mechanisms.
431 If you use a Negotiate authenticator, make sure you have at least
432 one acl of type proxy_auth active. By default, the negotiate
433 authenticator_program is not used.
434 The only supported program for this role is the ntlm_auth
435 program distributed as part of Samba, version 4 or later.
437 auth_param negotiate program @DEFAULT_PREFIX@/bin/ntlm_auth --helper-protocol=gss-spnego
439 "children" numberofchildren [startup=N] [idle=N]
440 The maximum number of authenticator processes to spawn (default 5).
441 If you start too few Squid will have to wait for them to
442 process a backlog of credential verifications, slowing it
443 down. When crendential verifications are done via a (slow)
444 network you are likely to need lots of authenticator
447 The startup= and idle= options permit some skew in the exact amount
448 run. A minimum of startup=N will begin during startup and reconfigure.
449 Squid will start more in groups of up to idle=N in an attempt to meet
450 traffic needs and to keep idle=N free above those traffic needs up to
453 auth_param negotiate children 20 startup=0 idle=1
456 If you experience problems with PUT/POST requests when using the
457 Negotiate authentication scheme then you can try setting this to
458 off. This will cause Squid to forcibly close the connection on
459 the initial requests where the browser asks which schemes are
460 supported by the proxy.
462 auth_param negotiate keep_alive on
467 #Recommended minimum configuration per scheme:
468 #auth_param negotiate program <uncomment and complete this line to activate>
469 #auth_param negotiate children 20 startup=0 idle=1
470 #auth_param negotiate keep_alive on
472 #auth_param ntlm program <uncomment and complete this line to activate>
473 #auth_param ntlm children 20 startup=0 idle=1
474 #auth_param ntlm keep_alive on
476 #auth_param digest program <uncomment and complete this line>
477 #auth_param digest children 20 startup=0 idle=1
478 #auth_param digest realm Squid proxy-caching web server
479 #auth_param digest nonce_garbage_interval 5 minutes
480 #auth_param digest nonce_max_duration 30 minutes
481 #auth_param digest nonce_max_count 50
483 #auth_param basic program <uncomment and complete this line>
484 #auth_param basic children 5 startup=5 idle=1
485 #auth_param basic realm Squid proxy-caching web server
486 #auth_param basic credentialsttl 2 hours
489 NAME: authenticate_cache_garbage_interval
492 LOC: Config.authenticateGCInterval
494 The time period between garbage collection across the username cache.
495 This is a tradeoff between memory utilization (long intervals - say
496 2 days) and CPU (short intervals - say 1 minute). Only change if you
500 NAME: authenticate_ttl
503 LOC: Config.authenticateTTL
505 The time a user & their credentials stay in the logged in
506 user cache since their last request. When the garbage
507 interval passes, all user credentials that have passed their
508 TTL are removed from memory.
511 NAME: authenticate_ip_ttl
513 LOC: Config.authenticateIpTTL
516 If you use proxy authentication and the 'max_user_ip' ACL,
517 this directive controls how long Squid remembers the IP
518 addresses associated with each user. Use a small value
519 (e.g., 60 seconds) if your users might change addresses
520 quickly, as is the case with dialups. You might be safe
521 using a larger value (e.g., 2 hours) in a corporate LAN
522 environment with relatively static address assignments.
527 -----------------------------------------------------------------------------
530 NAME: external_acl_type
531 TYPE: externalAclHelper
532 LOC: Config.externalAclHelperList
535 This option defines external acl classes using a helper program
536 to look up the status
538 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
542 ttl=n TTL in seconds for cached results (defaults to 3600
545 TTL for cached negative lookups (default same
548 Maximum number of acl helper processes spawned to service
549 external acl lookups of this type. (default 20)
551 Minimum number of acl helper processes to spawn during
552 startup and reconfigure to service external acl lookups
553 of this type. (default 0)
555 Number of acl helper processes to keep ahead of traffic
556 loads. Squid will spawn this many at once whenever load
557 rises above the capabilities of existing processes.
558 Up to the value of children-max. (default 1)
559 concurrency=n concurrency level per process. Only used with helpers
560 capable of processing more than one query at a time.
561 cache=n limit the result cache size, default is unbounded.
562 grace=n Percentage remaining of TTL where a refresh of a
563 cached entry should be initiated without needing to
564 wait for a new reply. (default is for no grace period)
565 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
566 ipv4 / ipv6 IP protocol used to communicate with this helper.
567 The default is to auto-detect IPv6 and use it when available.
569 FORMAT specifications
571 %LOGIN Authenticated user login name
572 %EXT_USER Username from previous external acl
573 %EXT_LOG Log details from previous external acl
574 %EXT_TAG Tag from previous external acl
575 %IDENT Ident user name
577 %SRCPORT Client source port
580 %PROTO Requested protocol
582 %PATH Requested URL path
583 %METHOD Request method
584 %MYADDR Squid interface address
585 %MYPORT Squid http_port number
586 %PATH Requested URL-path (including query-string if any)
587 %USER_CERT SSL User certificate in PEM format
588 %USER_CERTCHAIN SSL User certificate chain in PEM format
589 %USER_CERT_xx SSL User certificate subject attribute xx
590 %USER_CA_xx SSL User certificate issuer attribute xx
592 %>{Header} HTTP request header "Header"
594 HTTP request header "Hdr" list member "member"
596 HTTP request header list member using ; as
597 list separator. ; can be any non-alphanumeric
600 %<{Header} HTTP reply header "Header"
602 HTTP reply header "Hdr" list member "member"
604 HTTP reply header list member using ; as
605 list separator. ; can be any non-alphanumeric
608 %% The percent sign. Useful for helpers which need
609 an unchanging input format.
611 In addition to the above, any string specified in the referencing
612 acl will also be included in the helper request line, after the
613 specified formats (see the "acl external" directive)
615 The helper receives lines per the above format specification,
616 and returns lines starting with OK or ERR indicating the validity
617 of the request and optionally followed by additional keywords with
620 General result syntax:
622 OK/ERR keyword=value ...
626 user= The users name (login)
627 password= The users password (for login= cache_peer option)
628 message= Message describing the reason. Available as %o
630 tag= Apply a tag to a request (for both ERR and OK results)
631 Only sets a tag, does not alter existing tags.
632 log= String to be logged in access.log. Available as
633 %ea in logformat specifications
635 If protocol=3.0 (the default) then URL escaping is used to protect
636 each value in both requests and responses.
638 If using protocol=2.5 then all values need to be enclosed in quotes
639 if they may contain whitespace, or the whitespace escaped using \.
640 And quotes or \ characters within the keyword value must be \ escaped.
642 When using the concurrency= option the protocol is changed by
643 introducing a query channel tag infront of the request/response.
644 The query channel tag is a number between 0 and concurrency-1.
651 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
652 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
653 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
654 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
655 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
658 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
659 DEFAULT: localhost src 127.0.0.1/32 ::1
660 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
661 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
663 Defining an Access List
665 Every access list definition must begin with an aclname and acltype,
666 followed by either type-specific arguments or a quoted filename that
669 acl aclname acltype argument ...
670 acl aclname acltype "file" ...
672 When using "file", the file should contain one item per line.
674 By default, regular expressions are CASE-SENSITIVE.
675 To make them case-insensitive, use the -i option. To return case-sensitive
676 use the +i option between patterns, or make a new ACL line without -i.
678 Some acl types require suspending the current request in order
679 to access some external data source.
680 Those which do are marked with the tag [slow], those which
681 don't are marked as [fast].
682 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
683 for further information
685 ***** ACL TYPES AVAILABLE *****
687 acl aclname src ip-address/mask ... # clients IP address [fast]
688 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
689 acl aclname dst ip-address/mask ... # URL host's IP address [slow]
690 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
692 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
693 # The arp ACL requires the special configure option --enable-arp-acl.
694 # Furthermore, the ARP ACL code is not portable to all operating systems.
695 # It works on Linux, Solaris, Windows, FreeBSD, and some
696 # other *BSD variants.
699 # NOTE: Squid can only determine the MAC address for clients that are on
700 # the same subnet. If the client is on a different subnet,
701 # then Squid cannot find out its MAC address.
703 acl aclname srcdomain .foo.com ...
704 # reverse lookup, from client IP [slow]
705 acl aclname dstdomain .foo.com ...
706 # Destination server from URL [fast]
707 acl aclname srcdom_regex [-i] \.foo\.com ...
708 # regex matching client name [slow]
709 acl aclname dstdom_regex [-i] \.foo\.com ...
710 # regex matching server [fast]
712 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
713 # based URL is used and no match is found. The name "none" is used
714 # if the reverse lookup fails.
716 acl aclname src_as number ...
717 acl aclname dst_as number ...
719 # Except for access control, AS numbers can be used for
720 # routing of requests to specific caches. Here's an
721 # example for routing all requests for AS#1241 and only
722 # those to mycache.mydomain.net:
723 # acl asexample dst_as 1241
724 # cache_peer_access mycache.mydomain.net allow asexample
725 # cache_peer_access mycache_mydomain.net deny all
727 acl aclname peername myPeer ...
729 # match against a named cache_peer entry
730 # set unique name= on cache_peer lines for reliable use.
732 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
742 # h1:m1 must be less than h2:m2
744 acl aclname url_regex [-i] ^http:// ...
745 # regex matching on whole URL [fast]
746 acl aclname urlpath_regex [-i] \.gif$ ...
747 # regex matching on URL path [fast]
749 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
751 acl aclname localport 3128 ... # TCP port the client connected to [fast]
752 # NP: for interception mode this is usually '80'
754 acl aclname myportname 3128 ... # http(s)_port name [fast]
756 acl aclname proto HTTP FTP ... # request protocol [fast]
758 acl aclname method GET POST ... # HTTP request method [fast]
760 acl aclname http_status 200 301 500- 400-403 ...
761 # status code in reply [fast]
763 acl aclname browser [-i] regexp ...
764 # pattern match on User-Agent header (see also req_header below) [fast]
766 acl aclname referer_regex [-i] regexp ...
767 # pattern match on Referer header [fast]
768 # Referer is highly unreliable, so use with care
770 acl aclname ident username ...
771 acl aclname ident_regex [-i] pattern ...
772 # string match on ident output [slow]
773 # use REQUIRED to accept any non-null ident.
775 acl aclname proxy_auth [-i] username ...
776 acl aclname proxy_auth_regex [-i] pattern ...
777 # perform http authentication challenge to the client and match against
778 # supplied credentials [slow]
780 # takes a list of allowed usernames.
781 # use REQUIRED to accept any valid username.
783 # Will use proxy authentication in forward-proxy scenarios, and plain
784 # http authenticaiton in reverse-proxy scenarios
786 # NOTE: when a Proxy-Authentication header is sent but it is not
787 # needed during ACL checking the username is NOT logged
790 # NOTE: proxy_auth requires a EXTERNAL authentication program
791 # to check username/password combinations (see
792 # auth_param directive).
794 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
795 # as the browser needs to be configured for using a proxy in order
796 # to respond to proxy authentication.
798 acl aclname snmp_community string ...
799 # A community string to limit access to your SNMP Agent [fast]
802 # acl snmppublic snmp_community public
804 acl aclname maxconn number
805 # This will be matched when the client's IP address has
806 # more than <number> TCP connections established. [fast]
807 # NOTE: This only measures direct TCP links so X-Forwarded-For
808 # indirect clients are not counted.
810 acl aclname max_user_ip [-s] number
811 # This will be matched when the user attempts to log in from more
812 # than <number> different ip addresses. The authenticate_ip_ttl
813 # parameter controls the timeout on the ip entries. [fast]
814 # If -s is specified the limit is strict, denying browsing
815 # from any further IP addresses until the ttl has expired. Without
816 # -s Squid will just annoy the user by "randomly" denying requests.
817 # (the counter is reset each time the limit is reached and a
819 # NOTE: in acceleration mode or where there is mesh of child proxies,
820 # clients may appear to come from multiple addresses if they are
821 # going through proxy farms, so a limit of 1 may cause user problems.
823 acl aclname random probability
824 # Pseudo-randomly match requests. Based on the probability given.
825 # Probability may be written as a decimal (0.333), fraction (1/3)
826 # or ratio of matches:non-matches (3:5).
828 acl aclname req_mime_type [-i] mime-type ...
829 # regex match against the mime type of the request generated
830 # by the client. Can be used to detect file upload or some
831 # types HTTP tunneling requests [fast]
832 # NOTE: This does NOT match the reply. You cannot use this
833 # to match the returned file type.
835 acl aclname req_header header-name [-i] any\.regex\.here
836 # regex match against any of the known request headers. May be
837 # thought of as a superset of "browser", "referer" and "mime-type"
840 acl aclname rep_mime_type [-i] mime-type ...
841 # regex match against the mime type of the reply received by
842 # squid. Can be used to detect file download or some
843 # types HTTP tunneling requests. [fast]
844 # NOTE: This has no effect in http_access rules. It only has
845 # effect in rules that affect the reply data stream such as
848 acl aclname rep_header header-name [-i] any\.regex\.here
849 # regex match against any of the known reply headers. May be
850 # thought of as a superset of "browser", "referer" and "mime-type"
853 acl aclname external class_name [arguments...]
854 # external ACL lookup via a helper class defined by the
855 # external_acl_type directive [slow]
857 acl aclname user_cert attribute values...
858 # match against attributes in a user SSL certificate
859 # attribute is one of DN/C/O/CN/L/ST [fast]
861 acl aclname ca_cert attribute values...
862 # match against attributes a users issuing CA SSL certificate
863 # attribute is one of DN/C/O/CN/L/ST [fast]
865 acl aclname ext_user username ...
866 acl aclname ext_user_regex [-i] pattern ...
867 # string match on username returned by external acl helper [slow]
868 # use REQUIRED to accept any non-null user name.
870 acl aclname tag tagvalue ...
871 # string match on tag returned by external acl helper [slow]
873 acl aclname hier_code codename ...
874 # string match against squid hierarchy code(s); [fast]
875 # e.g., DIRECT, PARENT_HIT, NONE, etc.
877 # NOTE: This has no effect in http_access rules. It only has
878 # effect in rules that affect the reply data stream such as
882 acl aclname ssl_error errorname
883 # match against SSL certificate validation error [fast]
885 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
888 # The following can be used as shortcuts for certificate properties:
889 # [ssl::]certHasExpired: the "not after" field is in the past
890 # [ssl::]certNotYetValid: the "not before" field is in the future
891 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
892 # [ssl::]certSelfSigned: The certificate is self signed.
893 # [ssl::]certDomainMismatch: The certificate CN domain does not
894 # match the name the name of the host we are connecting to.
896 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
897 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
898 # predefined ACLs, just like the 'all' ACL.
900 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
901 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
905 acl macaddress arp 09:00:2b:23:45:67
906 acl myexample dst_as 1241
907 acl password proxy_auth REQUIRED
908 acl fileupload req_mime_type -i ^multipart/form-data$
909 acl javascript rep_mime_type -i ^application/x-javascript$
913 # Recommended minimum configuration:
916 # Example rule allowing access from your local networks.
917 # Adapt to list your (internal) IP networks from where browsing
919 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
920 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
921 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
922 acl localnet src fc00::/7 # RFC 4193 local private network range
923 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
925 acl SSL_ports port 443
926 acl Safe_ports port 80 # http
927 acl Safe_ports port 21 # ftp
928 acl Safe_ports port 443 # https
929 acl Safe_ports port 70 # gopher
930 acl Safe_ports port 210 # wais
931 acl Safe_ports port 1025-65535 # unregistered ports
932 acl Safe_ports port 280 # http-mgmt
933 acl Safe_ports port 488 # gss-http
934 acl Safe_ports port 591 # filemaker
935 acl Safe_ports port 777 # multiling http
936 acl CONNECT method CONNECT
940 NAME: follow_x_forwarded_for
942 IFDEF: FOLLOW_X_FORWARDED_FOR
943 LOC: Config.accessList.followXFF
944 DEFAULT_IF_NONE: deny all
946 Allowing or Denying the X-Forwarded-For header to be followed to
947 find the original source of a request.
949 Requests may pass through a chain of several other proxies
950 before reaching us. The X-Forwarded-For header will contain a
951 comma-separated list of the IP addresses in the chain, with the
952 rightmost address being the most recent.
954 If a request reaches us from a source that is allowed by this
955 configuration item, then we consult the X-Forwarded-For header
956 to see where that host received the request from. If the
957 X-Forwarded-For header contains multiple addresses, we continue
958 backtracking until we reach an address for which we are not allowed
959 to follow the X-Forwarded-For header, or until we reach the first
960 address in the list. For the purpose of ACL used in the
961 follow_x_forwarded_for directive the src ACL type always matches
962 the address we are testing and srcdomain matches its rDNS.
964 The end result of this process is an IP address that we will
965 refer to as the indirect client address. This address may
966 be treated as the client address for access control, ICAP, delay
967 pools and logging, depending on the acl_uses_indirect_client,
968 icap_uses_indirect_client, delay_pool_uses_indirect_client,
969 log_uses_indirect_client and tproxy_uses_indirect_client options.
971 This clause only supports fast acl types.
972 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
974 SECURITY CONSIDERATIONS:
976 Any host for which we follow the X-Forwarded-For header
977 can place incorrect information in the header, and Squid
978 will use the incorrect information as if it were the
979 source address of the request. This may enable remote
980 hosts to bypass any access control restrictions that are
981 based on the client's source addresses.
985 acl localhost src 127.0.0.1
986 acl my_other_proxy srcdomain .proxy.example.com
987 follow_x_forwarded_for allow localhost
988 follow_x_forwarded_for allow my_other_proxy
991 NAME: acl_uses_indirect_client
994 IFDEF: FOLLOW_X_FORWARDED_FOR
996 LOC: Config.onoff.acl_uses_indirect_client
998 Controls whether the indirect client address
999 (see follow_x_forwarded_for) is used instead of the
1000 direct client address in acl matching.
1002 NOTE: maxconn ACL considers direct TCP links and indirect
1003 clients will always have zero. So no match.
1006 NAME: delay_pool_uses_indirect_client
1009 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1011 LOC: Config.onoff.delay_pool_uses_indirect_client
1013 Controls whether the indirect client address
1014 (see follow_x_forwarded_for) is used instead of the
1015 direct client address in delay pools.
1018 NAME: log_uses_indirect_client
1021 IFDEF: FOLLOW_X_FORWARDED_FOR
1023 LOC: Config.onoff.log_uses_indirect_client
1025 Controls whether the indirect client address
1026 (see follow_x_forwarded_for) is used instead of the
1027 direct client address in the access log.
1030 NAME: tproxy_uses_indirect_client
1033 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1035 LOC: Config.onoff.tproxy_uses_indirect_client
1037 Controls whether the indirect client address
1038 (see follow_x_forwarded_for) is used instead of the
1039 direct client address when spoofing the outgoing client.
1041 This has no effect on requests arriving in non-tproxy
1044 SECURITY WARNING: Usage of this option is dangerous
1045 and should not be used trivially. Correct configuration
1046 of follow_x_forewarded_for with a limited set of trusted
1047 sources is required to prevent abuse of your proxy.
1052 LOC: Config.accessList.http
1053 DEFAULT_IF_NONE: deny all
1055 Allowing or Denying access based on defined access lists
1057 Access to the HTTP port:
1058 http_access allow|deny [!]aclname ...
1060 NOTE on default values:
1062 If there are no "access" lines present, the default is to deny
1065 If none of the "access" lines cause a match, the default is the
1066 opposite of the last line in the list. If the last line was
1067 deny, the default is allow. Conversely, if the last line
1068 is allow, the default will be deny. For these reasons, it is a
1069 good idea to have an "deny all" entry at the end of your access
1070 lists to avoid potential confusion.
1072 This clause supports both fast and slow acl types.
1073 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1078 # Recommended minimum Access Permission configuration:
1080 # Only allow cachemgr access from localhost
1081 http_access allow localhost manager
1082 http_access deny manager
1084 # Deny requests to certain unsafe ports
1085 http_access deny !Safe_ports
1087 # Deny CONNECT to other than secure SSL ports
1088 http_access deny CONNECT !SSL_ports
1090 # We strongly recommend the following be uncommented to protect innocent
1091 # web applications running on the proxy server who think the only
1092 # one who can access services on "localhost" is a local user
1093 #http_access deny to_localhost
1096 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1099 # Example rule allowing access from your local networks.
1100 # Adapt localnet in the ACL section to list your (internal) IP networks
1101 # from where browsing should be allowed
1102 http_access allow localnet
1103 http_access allow localhost
1105 # And finally deny all other access to this proxy
1106 http_access deny all
1110 NAME: adapted_http_access http_access2
1112 LOC: Config.accessList.adapted_http
1115 Allowing or Denying access based on defined access lists
1117 Essentially identical to http_access, but runs after redirectors
1118 and ICAP/eCAP adaptation. Allowing access control based on their
1121 If not set then only http_access is used.
1124 NAME: http_reply_access
1126 LOC: Config.accessList.reply
1129 Allow replies to client requests. This is complementary to http_access.
1131 http_reply_access allow|deny [!] aclname ...
1133 NOTE: if there are no access lines present, the default is to allow
1136 If none of the access lines cause a match the opposite of the
1137 last line will apply. Thus it is good practice to end the rules
1138 with an "allow all" or "deny all" entry.
1140 This clause supports both fast and slow acl types.
1141 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1146 LOC: Config.accessList.icp
1147 DEFAULT_IF_NONE: deny all
1149 Allowing or Denying access to the ICP port based on defined
1152 icp_access allow|deny [!]aclname ...
1154 See http_access for details
1156 This clause only supports fast acl types.
1157 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1159 # Allow ICP queries from local networks only
1160 #icp_access allow localnet
1161 #icp_access deny all
1167 LOC: Config.accessList.htcp
1168 DEFAULT_IF_NONE: deny all
1170 Allowing or Denying access to the HTCP port based on defined
1173 htcp_access allow|deny [!]aclname ...
1175 See http_access for details
1177 NOTE: The default if no htcp_access lines are present is to
1178 deny all traffic. This default may cause problems with peers
1179 using the htcp option.
1181 This clause only supports fast acl types.
1182 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1184 # Allow HTCP queries from local networks only
1185 #htcp_access allow localnet
1186 #htcp_access deny all
1189 NAME: htcp_clr_access
1192 LOC: Config.accessList.htcp_clr
1193 DEFAULT_IF_NONE: deny all
1195 Allowing or Denying access to purge content using HTCP based
1196 on defined access lists
1198 htcp_clr_access allow|deny [!]aclname ...
1200 See http_access for details
1202 This clause only supports fast acl types.
1203 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1205 # Allow HTCP CLR requests from trusted peers
1206 acl htcp_clr_peer src 172.16.1.2
1207 htcp_clr_access allow htcp_clr_peer
1212 LOC: Config.accessList.miss
1215 Determins whether network access is permitted when satisfying a request.
1218 to force your neighbors to use you as a sibling instead of
1221 acl localclients src 172.16.0.0/16
1222 miss_access allow localclients
1223 miss_access deny !localclients
1225 This means only your local clients are allowed to fetch relayed/MISS
1226 replies from the network and all other clients can only fetch cached
1230 The default for this setting allows all clients who passed the
1231 http_access rules to relay via this proxy.
1233 This clause only supports fast acl types.
1234 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1237 NAME: ident_lookup_access
1240 DEFAULT_IF_NONE: deny all
1241 LOC: Ident::TheConfig.identLookup
1243 A list of ACL elements which, if matched, cause an ident
1244 (RFC 931) lookup to be performed for this request. For
1245 example, you might choose to always perform ident lookups
1246 for your main multi-user Unix boxes, but not for your Macs
1247 and PCs. By default, ident lookups are not performed for
1250 To enable ident lookups for specific client addresses, you
1251 can follow this example:
1253 acl ident_aware_hosts src 198.168.1.0/24
1254 ident_lookup_access allow ident_aware_hosts
1255 ident_lookup_access deny all
1257 Only src type ACL checks are fully supported. A srcdomain
1258 ACL might work at times, but it will not always provide
1261 This clause only supports fast acl types.
1262 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1265 NAME: reply_body_max_size
1266 COMMENT: size [acl acl...]
1269 LOC: Config.ReplyBodySize
1271 This option specifies the maximum size of a reply body. It can be
1272 used to prevent users from downloading very large files, such as
1273 MP3's and movies. When the reply headers are received, the
1274 reply_body_max_size lines are processed, and the first line where
1275 all (if any) listed ACLs are true is used as the maximum body size
1278 This size is checked twice. First when we get the reply headers,
1279 we check the content-length value. If the content length value exists
1280 and is larger than the allowed size, the request is denied and the
1281 user receives an error message that says "the request or reply
1282 is too large." If there is no content-length, and the reply
1283 size exceeds this limit, the client's connection is just closed
1284 and they will receive a partial reply.
1286 WARNING: downstream caches probably can not detect a partial reply
1287 if there is no content-length header, so they will cache
1288 partial responses and give them out as hits. You should NOT
1289 use this option if you have downstream caches.
1291 WARNING: A maximum size smaller than the size of squid's error messages
1292 will cause an infinite loop and crash squid. Ensure that the smallest
1293 non-zero value you use is greater that the maximum header size plus
1294 the size of your largest error page.
1296 If you set this parameter none (the default), there will be
1299 Configuration Format is:
1300 reply_body_max_size SIZE UNITS [acl ...]
1302 reply_body_max_size 10 MB
1308 -----------------------------------------------------------------------------
1311 NAME: http_port ascii_port
1314 LOC: Config.Sockaddr.http
1316 Usage: port [mode] [options]
1317 hostname:port [mode] [options]
1318 1.2.3.4:port [mode] [options]
1320 The socket addresses where Squid will listen for HTTP client
1321 requests. You may specify multiple socket addresses.
1322 There are three forms: port alone, hostname with port, and
1323 IP address with port. If you specify a hostname or IP
1324 address, Squid binds the socket to that specific
1325 address. Most likely, you do not need to bind to a specific
1326 address, so you can use the port number alone.
1328 If you are running Squid in accelerator mode, you
1329 probably want to listen on port 80 also, or instead.
1331 The -a command line option may be used to specify additional
1332 port(s) where Squid listens for proxy request. Such ports will
1333 be plain proxy ports with no options.
1335 You may specify multiple socket addresses on multiple lines.
1339 intercept Support for IP-Layer interception of
1340 outgoing requests without browser settings.
1341 NP: disables authentication and IPv6 on the port.
1343 tproxy Support Linux TPROXY for spoofing outgoing
1344 connections using the client IP address.
1345 NP: disables authentication and maybe IPv6 on the port.
1347 accel Accelerator / reverse proxy mode
1349 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1350 establish secure connection with the client and with
1351 the server, decrypt HTTPS messages as they pass through
1352 Squid, and treat them as unencrypted HTTP messages,
1353 becoming the man-in-the-middle.
1355 The ssl_bump option is required to fully enable
1356 bumping of CONNECT requests.
1358 Omitting the mode flag causes default forward proxy mode to be used.
1361 Accelerator Mode Options:
1363 defaultsite=domainname
1364 What to use for the Host: header if it is not present
1365 in a request. Determines what site (not origin server)
1366 accelerators should consider the default.
1368 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1370 protocol= Protocol to reconstruct accelerated requests with.
1371 Defaults to http for http_port and https for
1374 vport Virtual host port support. Using the http_port number
1375 instead of the port passed on Host: headers.
1377 vport=NN Virtual host port support. Using the specified port
1378 number instead of the port passed on Host: headers.
1381 Act as if this Squid is the origin server.
1382 This currently means generate new Date: and Expires:
1383 headers on HIT instead of adding Age:.
1385 ignore-cc Ignore request Cache-Control headers.
1387 WARNING: This option violates HTTP specifications if
1388 used in non-accelerator setups.
1390 allow-direct Allow direct forwarding in accelerator mode. Normally
1391 accelerated requests are denied direct forwarding as if
1392 never_direct was used.
1394 WARNING: this option opens accelerator mode to security
1395 vulnerabilities usually only affecting in interception
1396 mode. Make sure to protect forwarding with suitable
1397 http_access rules when using this.
1400 SSL Bump Mode Options:
1401 In addition to these options ssl-bump requires TLS/SSL options.
1403 generate-host-certificates[=<on|off>]
1404 Dynamically create SSL server certificates for the
1405 destination hosts of bumped CONNECT requests.When
1406 enabled, the cert and key options are used to sign
1407 generated certificates. Otherwise generated
1408 certificate will be selfsigned.
1409 If there is a CA certificate lifetime of the generated
1410 certificate equals lifetime of the CA certificate. If
1411 generated certificate is selfsigned lifetime is three
1413 This option is enabled by default when ssl-bump is used.
1414 See the ssl-bump option above for more information.
1416 dynamic_cert_mem_cache_size=SIZE
1417 Approximate total RAM size spent on cached generated
1418 certificates. If set to zero, caching is disabled. The
1419 default value is 4MB.
1423 cert= Path to SSL certificate (PEM format).
1425 key= Path to SSL private key file (PEM format)
1426 if not specified, the certificate file is
1427 assumed to be a combined certificate and
1430 version= The version of SSL/TLS supported
1431 1 automatic (default)
1438 cipher= Colon separated list of supported ciphers.
1439 NOTE: some ciphers such as EDH ciphers depend on
1440 additional settings. If those settings are
1441 omitted the ciphers may be silently ignored
1442 by the OpenSSL library.
1444 options= Various SSL implementation options. The most important
1446 NO_SSLv2 Disallow the use of SSLv2
1447 NO_SSLv3 Disallow the use of SSLv3
1448 NO_TLSv1 Disallow the use of TLSv1.0
1449 NO_TLSv1_1 Disallow the use of TLSv1.1
1450 NO_TLSv1_2 Disallow the use of TLSv1.2
1451 SINGLE_DH_USE Always create a new key when using
1452 temporary/ephemeral DH key exchanges
1453 ALL Enable various bug workarounds
1454 suggested as "harmless" by OpenSSL
1455 Be warned that this reduces SSL/TLS
1456 strength to some attacks.
1457 See OpenSSL SSL_CTX_set_options documentation for a
1458 complete list of options.
1460 clientca= File containing the list of CAs to use when
1461 requesting a client certificate.
1463 cafile= File containing additional CA certificates to
1464 use when verifying client certificates. If unset
1465 clientca will be used.
1467 capath= Directory containing additional CA certificates
1468 and CRL lists to use when verifying client certificates.
1470 crlfile= File of additional CRL lists to use when verifying
1471 the client certificate, in addition to CRLs stored in
1472 the capath. Implies VERIFY_CRL flag below.
1474 dhparams= File containing DH parameters for temporary/ephemeral
1475 DH key exchanges. See OpenSSL documentation for details
1476 on how to create this file.
1477 WARNING: EDH ciphers will be silently disabled if this
1480 sslflags= Various flags modifying the use of SSL:
1482 Don't request client certificates
1483 immediately, but wait until acl processing
1484 requires a certificate (not yet implemented).
1486 Don't use the default CA lists built in
1489 Don't allow for session reuse. Each connection
1490 will result in a new SSL session.
1492 Verify CRL lists when accepting client
1495 Verify CRL lists for all certificates in the
1496 client certificate chain.
1498 sslcontext= SSL session ID context identifier.
1502 connection-auth[=on|off]
1503 use connection-auth=off to tell Squid to prevent
1504 forwarding Microsoft connection oriented authentication
1505 (NTLM, Negotiate and Kerberos)
1507 disable-pmtu-discovery=
1508 Control Path-MTU discovery usage:
1509 off lets OS decide on what to do (default).
1510 transparent disable PMTU discovery when transparent
1512 always disable always PMTU discovery.
1514 In many setups of transparently intercepting proxies
1515 Path-MTU discovery can not work on traffic towards the
1516 clients. This is the case when the intercepting device
1517 does not fully track connections and fails to forward
1518 ICMP must fragment messages to the cache server. If you
1519 have such setup and experience that certain clients
1520 sporadically hang or never complete requests set
1521 disable-pmtu-discovery option to 'transparent'.
1523 name= Specifies a internal name for the port. Defaults to
1524 the port specification (port or addr:port)
1526 tcpkeepalive[=idle,interval,timeout]
1527 Enable TCP keepalive probes of idle connections.
1528 In seconds; idle is the initial time before TCP starts
1529 probing the connection, interval how often to probe, and
1530 timeout the time before giving up.
1532 If you run Squid on a dual-homed machine with an internal
1533 and an external interface we recommend you to specify the
1534 internal address:port in http_port. This way Squid will only be
1535 visible on the internal address.
1539 # Squid normally listens to port 3128
1540 http_port @DEFAULT_HTTP_PORT@
1548 LOC: Config.Sockaddr.https
1550 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1552 The socket address where Squid will listen for client requests made
1553 over TLS or SSL connections. Commonly referred to as HTTPS.
1555 This is most useful for situations where you are running squid in
1556 accelerator mode and you want to do the SSL work at the accelerator level.
1558 You may specify multiple socket addresses on multiple lines,
1559 each with their own SSL certificate and/or options.
1563 accel Accelerator / reverse proxy mode
1565 intercept Support for IP-Layer interception of
1566 outgoing requests without browser settings.
1567 NP: disables authentication and IPv6 on the port.
1569 tproxy Support Linux TPROXY for spoofing outgoing
1570 connections using the client IP address.
1571 NP: disables authentication and maybe IPv6 on the port.
1573 ssl-bump For each intercepted connection allowed by ssl_bump
1574 ACLs, establish a secure connection with the client and with
1575 the server, decrypt HTTPS messages as they pass through
1576 Squid, and treat them as unencrypted HTTP messages,
1577 becoming the man-in-the-middle.
1579 An "ssl_bump server-first" match is required to
1580 fully enable bumping of intercepted SSL connections.
1582 Requires tproxy or intercept.
1584 Omitting the mode flag causes default forward proxy mode to be used.
1587 See http_port for a list of generic options
1592 cert= Path to SSL certificate (PEM format).
1594 key= Path to SSL private key file (PEM format)
1595 if not specified, the certificate file is
1596 assumed to be a combined certificate and
1599 version= The version of SSL/TLS supported
1600 1 automatic (default)
1605 cipher= Colon separated list of supported ciphers.
1607 options= Various SSL engine options. The most important
1609 NO_SSLv2 Disallow the use of SSLv2
1610 NO_SSLv3 Disallow the use of SSLv3
1611 NO_TLSv1 Disallow the use of TLSv1
1612 SINGLE_DH_USE Always create a new key when using
1613 temporary/ephemeral DH key exchanges
1614 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1615 documentation for a complete list of options.
1617 clientca= File containing the list of CAs to use when
1618 requesting a client certificate.
1620 cafile= File containing additional CA certificates to
1621 use when verifying client certificates. If unset
1622 clientca will be used.
1624 capath= Directory containing additional CA certificates
1625 and CRL lists to use when verifying client certificates.
1627 crlfile= File of additional CRL lists to use when verifying
1628 the client certificate, in addition to CRLs stored in
1629 the capath. Implies VERIFY_CRL flag below.
1631 dhparams= File containing DH parameters for temporary/ephemeral
1634 sslflags= Various flags modifying the use of SSL:
1636 Don't request client certificates
1637 immediately, but wait until acl processing
1638 requires a certificate (not yet implemented).
1640 Don't use the default CA lists built in
1643 Don't allow for session reuse. Each connection
1644 will result in a new SSL session.
1646 Verify CRL lists when accepting client
1649 Verify CRL lists for all certificates in the
1650 client certificate chain.
1652 sslcontext= SSL session ID context identifier.
1654 generate-host-certificates[=<on|off>]
1655 Dynamically create SSL server certificates for the
1656 destination hosts of bumped SSL requests.When
1657 enabled, the cert and key options are used to sign
1658 generated certificates. Otherwise generated
1659 certificate will be selfsigned.
1660 If there is CA certificate life time of generated
1661 certificate equals lifetime of CA certificate. If
1662 generated certificate is selfsigned lifetime is three
1664 This option is enabled by default when SslBump is used.
1665 See the sslBump option above for more information.
1667 dynamic_cert_mem_cache_size=SIZE
1668 Approximate total RAM size spent on cached generated
1669 certificates. If set to zero, caching is disabled. The
1670 default value is 4MB.
1672 See http_port for a list of available options.
1675 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1678 LOC: Ip::Qos::TheConfig.tosToServer
1680 Allows you to select a TOS/Diffserv value for packets outgoing
1681 on the server side, based on an ACL.
1683 tcp_outgoing_tos ds-field [!]aclname ...
1685 Example where normal_service_net uses the TOS value 0x00
1686 and good_service_net uses 0x20
1688 acl normal_service_net src 10.0.0.0/24
1689 acl good_service_net src 10.0.1.0/24
1690 tcp_outgoing_tos 0x00 normal_service_net
1691 tcp_outgoing_tos 0x20 good_service_net
1693 TOS/DSCP values really only have local significance - so you should
1694 know what you're specifying. For more information, see RFC2474,
1695 RFC2475, and RFC3260.
1697 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1698 "default" to use whatever default your host has. Note that in
1699 practice often only multiples of 4 is usable as the two rightmost bits
1700 have been redefined for use by ECN (RFC 3168 section 23.1).
1702 Processing proceeds in the order specified, and stops at first fully
1706 NAME: clientside_tos
1709 LOC: Ip::Qos::TheConfig.tosToClient
1711 Allows you to select a TOS/Diffserv value for packets being transmitted
1712 on the client-side, based on an ACL.
1714 clientside_tos ds-field [!]aclname ...
1716 Example where normal_service_net uses the TOS value 0x00
1717 and good_service_net uses 0x20
1719 acl normal_service_net src 10.0.0.0/24
1720 acl good_service_net src 10.0.1.0/24
1721 clientside_tos 0x00 normal_service_net
1722 clientside_tos 0x20 good_service_net
1724 Note: This feature is incompatible with qos_flows. Any TOS values set here
1725 will be overwritten by TOS values in qos_flows.
1728 NAME: tcp_outgoing_mark
1730 IFDEF: SO_MARK&&USE_LIBCAP
1732 LOC: Ip::Qos::TheConfig.nfmarkToServer
1734 Allows you to apply a Netfilter mark value to outgoing packets
1735 on the server side, based on an ACL.
1737 tcp_outgoing_mark mark-value [!]aclname ...
1739 Example where normal_service_net uses the mark value 0x00
1740 and good_service_net uses 0x20
1742 acl normal_service_net src 10.0.0.0/24
1743 acl good_service_net src 10.0.1.0/24
1744 tcp_outgoing_mark 0x00 normal_service_net
1745 tcp_outgoing_mark 0x20 good_service_net
1748 NAME: clientside_mark
1750 IFDEF: SO_MARK&&USE_LIBCAP
1752 LOC: Ip::Qos::TheConfig.nfmarkToClient
1754 Allows you to apply a Netfilter mark value to packets being transmitted
1755 on the client-side, based on an ACL.
1757 clientside_mark mark-value [!]aclname ...
1759 Example where normal_service_net uses the mark value 0x00
1760 and good_service_net uses 0x20
1762 acl normal_service_net src 10.0.0.0/24
1763 acl good_service_net src 10.0.1.0/24
1764 clientside_mark 0x00 normal_service_net
1765 clientside_mark 0x20 good_service_net
1767 Note: This feature is incompatible with qos_flows. Any mark values set here
1768 will be overwritten by mark values in qos_flows.
1775 LOC: Ip::Qos::TheConfig
1777 Allows you to select a TOS/DSCP value to mark outgoing
1778 connections with, based on where the reply was sourced. For
1779 platforms using netfilter, allows you to set a netfilter mark
1780 value instead of, or in addition to, a TOS value.
1782 TOS values really only have local significance - so you should
1783 know what you're specifying. For more information, see RFC2474,
1784 RFC2475, and RFC3260.
1786 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1787 in practice often only multiples of 4 is usable as the two rightmost bits
1788 have been redefined for use by ECN (RFC 3168 section 23.1).
1790 Mark values can be any unsigned 32-bit integer value.
1792 This setting is configured by setting the following values:
1794 tos|mark Whether to set TOS or netfilter mark values
1796 local-hit=0xFF Value to mark local cache hits.
1798 sibling-hit=0xFF Value to mark hits from sibling peers.
1800 parent-hit=0xFF Value to mark hits from parent peers.
1802 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
1803 over the preserve-miss feature (see below), unless
1804 mask is specified, in which case only the bits
1805 specified in the mask are written.
1807 The TOS variant of the following features are only possible on Linux
1808 and require your kernel to be patched with the TOS preserving ZPH
1809 patch, available from http://zph.bratcheda.org
1810 No patch is needed to preserve the netfilter mark, which will work
1811 with all variants of netfilter.
1813 disable-preserve-miss
1814 This option disables the preservation of the TOS or netfilter
1815 mark. By default, the existing TOS or netfilter mark value of
1816 the response coming from the remote server will be retained
1817 and masked with miss-mark.
1818 NOTE: in the case of a netfilter mark, the mark must be set on
1819 the connection (using the CONNMARK target) not on the packet
1823 Allows you to mask certain bits in the TOS or mark value
1824 received from the remote server, before copying the value to
1825 the TOS sent towards clients.
1826 Default for tos: 0xFF (TOS from server is not changed).
1827 Default for mark: 0xFFFFFFFF (mark from server is not changed).
1829 All of these features require the --enable-zph-qos compilation flag
1830 (enabled by default). Netfilter marking also requires the
1831 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
1832 libcap 2.09+ (--with-libcap).
1836 NAME: tcp_outgoing_address
1839 LOC: Config.accessList.outgoing_address
1841 Allows you to map requests to different outgoing IP addresses
1842 based on the username or source address of the user making
1845 tcp_outgoing_address ipaddr [[!]aclname] ...
1848 Forwarding clients with dedicated IPs for certain subnets.
1850 acl normal_service_net src 10.0.0.0/24
1851 acl good_service_net src 10.0.2.0/24
1853 tcp_outgoing_address 2001:db8::c001 good_service_net
1854 tcp_outgoing_address 10.1.0.2 good_service_net
1856 tcp_outgoing_address 2001:db8::beef normal_service_net
1857 tcp_outgoing_address 10.1.0.1 normal_service_net
1859 tcp_outgoing_address 2001:db8::1
1860 tcp_outgoing_address 10.1.0.3
1862 Processing proceeds in the order specified, and stops at first fully
1865 Squid will add an implicit IP version test to each line.
1866 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
1867 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
1870 NOTE: The use of this directive using client dependent ACLs is
1871 incompatible with the use of server side persistent connections. To
1872 ensure correct results it is best to set server_persistent_connections
1873 to off when using this directive in such configurations.
1875 NOTE: The use of this directive to set a local IP on outgoing TCP links
1876 is incompatible with using TPROXY to set client IP out outbound TCP links.
1877 When needing to contact peers use the no-tproxy cache_peer option and the
1878 client_dst_passthru directive re-enable normal forwarding such as this.
1882 NAME: host_verify_strict
1885 LOC: Config.onoff.hostStrictVerify
1887 Regardless of this option setting, when dealing with intercepted
1888 traffic, Squid always verifies that the destination IP address matches
1889 the Host header domain or IP (called 'authority form URL').
1891 This enforcement is performed to satisfy a MUST-level requirement in
1892 RFC 2616 section 14.23: "The Host field value MUST represent the naming
1893 authority of the origin server or gateway given by the original URL".
1896 Squid always responds with an HTTP 409 (Conflict) error
1897 page and logs a security warning if there is no match.
1899 Squid verifies that the destination IP address matches
1900 the Host header for forward-proxy and reverse-proxy traffic
1901 as well. For those traffic types, Squid also enables the
1902 following checks, comparing the corresponding Host header
1903 and Request-URI components:
1905 * The host names (domain or IP) must be identical,
1906 but valueless or missing Host header disables all checks.
1907 For the two host names to match, both must be either IP
1910 * Port numbers must be identical, but if a port is missing
1911 the scheme-default port is assumed.
1914 When set to OFF (the default):
1915 Squid allows suspicious requests to continue but logs a
1916 security warning and blocks caching of the response.
1918 * Forward-proxy traffic is not checked at all.
1920 * Reverse-proxy traffic is not checked at all.
1922 * Intercepted traffic which passes verification is handled
1925 * Intercepted requests which fail verification are sent
1926 to the client original destination instead of DIRECT.
1927 This overrides 'client_dst_passthru off'.
1929 For now suspicious intercepted CONNECT requests are always
1930 responded to with an HTTP 409 (Conflict) error page.
1935 As described in CVE-2009-0801 when the Host: header alone is used
1936 to determine the destination of a request it becomes trivial for
1937 malicious scripts on remote websites to bypass browser same-origin
1938 security policy and sandboxing protections.
1940 The cause of this is that such applets are allowed to perform their
1941 own HTTP stack, in which case the same-origin policy of the browser
1942 sandbox only verifies that the applet tries to contact the same IP
1943 as from where it was loaded at the IP level. The Host: header may
1944 be different from the connected IP and approved origin.
1948 NAME: client_dst_passthru
1951 LOC: Config.onoff.client_dst_passthru
1953 With NAT or TPROXY intercepted traffic Squid may pass the request
1954 directly to the original client destination IP or seek a faster
1955 source using the HTTP Host header.
1957 Using Host to locate alternative servers can provide faster
1958 connectivity with a range of failure recovery options.
1959 But can also lead to connectivity trouble when the client and
1960 server are attempting stateful interactions unaware of the proxy.
1962 This option (on by default) prevents alternative DNS entries being
1963 located to send intercepted traffic DIRECT to an origin server.
1964 The clients original destination IP and port will be used instead.
1966 Regardless of this option setting, when dealing with intercepted
1967 traffic Squid will verify the Host: header and any traffic which
1968 fails Host verification will be treated as if this option were ON.
1970 see host_verify_strict for details on the verification process.
1975 -----------------------------------------------------------------------------
1978 NAME: ssl_unclean_shutdown
1982 LOC: Config.SSL.unclean_shutdown
1984 Some browsers (especially MSIE) bugs out on SSL shutdown
1991 LOC: Config.SSL.ssl_engine
1994 The OpenSSL engine to use. You will need to set this if you
1995 would like to use hardware SSL acceleration for example.
1998 NAME: sslproxy_client_certificate
2001 LOC: Config.ssl_client.cert
2004 Client SSL Certificate to use when proxying https:// URLs
2007 NAME: sslproxy_client_key
2010 LOC: Config.ssl_client.key
2013 Client SSL Key to use when proxying https:// URLs
2016 NAME: sslproxy_version
2019 LOC: Config.ssl_client.version
2022 SSL version level to use when proxying https:// URLs
2024 The versions of SSL/TLS supported:
2026 1 automatic (default)
2034 NAME: sslproxy_options
2037 LOC: Config.ssl_client.options
2040 SSL implementation options to use when proxying https:// URLs
2042 The most important being:
2044 NO_SSLv2 Disallow the use of SSLv2
2045 NO_SSLv3 Disallow the use of SSLv3
2046 NO_TLSv1 Disallow the use of TLSv1.0
2047 NO_TLSv1_1 Disallow the use of TLSv1.1
2048 NO_TLSv1_2 Disallow the use of TLSv1.2
2050 Always create a new key when using temporary/ephemeral
2053 Disable use of RFC5077 session tickets. Some servers
2054 may have problems understanding the TLS extension due
2055 to ambiguous specification in RFC4507.
2056 ALL Enable various bug workarounds suggested as "harmless"
2057 by OpenSSL. Be warned that this may reduce SSL/TLS
2058 strength to some attacks.
2060 See the OpenSSL SSL_CTX_set_options documentation for a
2061 complete list of possible options.
2064 NAME: sslproxy_cipher
2067 LOC: Config.ssl_client.cipher
2070 SSL cipher list to use when proxying https:// URLs
2072 Colon separated list of supported ciphers.
2075 NAME: sslproxy_cafile
2078 LOC: Config.ssl_client.cafile
2081 file containing CA certificates to use when verifying server
2082 certificates while proxying https:// URLs
2085 NAME: sslproxy_capath
2088 LOC: Config.ssl_client.capath
2091 directory containing CA certificates to use when verifying
2092 server certificates while proxying https:// URLs
2097 TYPE: sslproxy_ssl_bump
2098 LOC: Config.accessList.ssl_bump
2101 This option is consulted when a CONNECT request is received on
2102 an http_port (or a new connection is intercepted at an
2103 https_port), provided that port was configured with an ssl-bump
2104 flag. The subsequent data on the connection is either treated as
2105 HTTPS and decrypted OR tunneled at TCP level without decryption,
2106 depending on the first bumping "mode" which ACLs match.
2108 ssl_bump <mode> [!]acl ...
2110 The following bumping modes are supported:
2113 Allow bumping of the connection. Establish a secure connection
2114 with the client first, then connect to the server. This old mode
2115 does not allow Squid to mimic server SSL certificate and does
2116 not work with intercepted SSL connections.
2119 Allow bumping of the connection. Establish a secure connection
2120 with the server first, then establish a secure connection with
2121 the client, using a mimicked server certificate. Works with both
2122 CONNECT requests and intercepted SSL connections.
2125 Become a TCP tunnel without decoding the connection.
2126 Works with both CONNECT requests and intercepted SSL
2127 connections. This is the default behavior when no
2128 ssl_bump option is given or no ssl_bump ACLs match.
2130 By default, no connections are bumped.
2132 The first matching ssl_bump option wins. If no ACLs match, the
2133 connection is not bumped. Unlike most allow/deny ACL lists, ssl_bump
2134 does not have an implicit "negate the last given option" rule. You
2135 must make that rule explicit if you convert old ssl_bump allow/deny
2136 rules that rely on such an implicit rule.
2138 This clause supports both fast and slow acl types.
2139 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2141 See also: http_port ssl-bump, https_port ssl-bump
2144 # Example: Bump all requests except those originating from
2145 # localhost and those going to example.com.
2147 acl broken_sites dstdomain .example.com
2148 ssl_bump none localhost
2149 ssl_bump none broken_sites
2150 ssl_bump server-first all
2153 NAME: sslproxy_flags
2156 LOC: Config.ssl_client.flags
2159 Various flags modifying the use of SSL while proxying https:// URLs:
2160 DONT_VERIFY_PEER Accept certificates that fail verification.
2161 For refined control, see sslproxy_cert_error.
2162 NO_DEFAULT_CA Don't use the default CA list built in
2166 NAME: sslproxy_cert_error
2169 LOC: Config.ssl_client.cert_error
2172 Use this ACL to bypass server certificate validation errors.
2174 For example, the following lines will bypass all validation errors
2175 when talking to servers for example.com. All other
2176 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2178 acl BrokenButTrustedServers dstdomain example.com
2179 sslproxy_cert_error allow BrokenButTrustedServers
2180 sslproxy_cert_error deny all
2182 This clause only supports fast acl types.
2183 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2184 Using slow acl types may result in server crashes
2186 Without this option, all server certificate validation errors
2187 terminate the transaction. Bypassing validation errors is dangerous
2188 because an error usually implies that the server cannot be trusted and
2189 the connection may be insecure.
2191 See also: sslproxy_flags and DONT_VERIFY_PEER.
2193 Default setting: sslproxy_cert_error deny all
2196 NAME: sslproxy_cert_sign
2199 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2200 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2201 POSTSCRIPTUM: signTrusted all
2202 TYPE: sslproxy_cert_sign
2203 LOC: Config.ssl_client.cert_sign
2206 sslproxy_cert_sign <signing algorithm> acl ...
2208 The following certificate signing algorithms are supported:
2210 Sign using the configured CA certificate which is usually
2211 placed in and trusted by end-user browsers. This is the
2212 default for trusted origin server certificates.
2214 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2215 This is the default for untrusted origin server certificates
2216 that are not self-signed (see ssl::certUntrusted).
2218 Sign using a self-signed certificate with the right CN to
2219 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2220 browser. This is the default for self-signed origin server
2221 certificates (see ssl::certSelfSigned).
2223 This clause only supports fast acl types.
2225 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2226 signing algorithm to generate the certificate and ignores all
2227 subsequent sslproxy_cert_sign options (the first match wins). If no
2228 acl(s) match, the default signing algorithm is determined by errors
2229 detected when obtaining and validating the origin server certificate.
2231 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2232 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2233 CONNECT request that carries a domain name. In all other cases (CONNECT
2234 to an IP address or an intercepted SSL connection), Squid cannot detect
2235 the domain mismatch at certificate generation time when
2236 bump-server-first is used.
2239 NAME: sslproxy_cert_adapt
2242 TYPE: sslproxy_cert_adapt
2243 LOC: Config.ssl_client.cert_adapt
2246 sslproxy_cert_adapt <adaptation algorithm> acl ...
2248 The following certificate adaptation algorithms are supported:
2250 Sets the "Not After" property to the "Not After" property of
2251 the CA certificate used to sign generated certificates.
2253 Sets the "Not Before" property to the "Not Before" property of
2254 the CA certificate used to sign generated certificates.
2255 setCommonName or setCommonName{CN}
2256 Sets Subject.CN property to the host name specified as a
2257 CN parameter or, if no explicit CN parameter was specified,
2258 extracted from the CONNECT request. It is a misconfiguration
2259 to use setCommonName without an explicit parameter for
2260 intercepted or tproxied SSL connections.
2262 This clause only supports fast acl types.
2264 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2265 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2266 corresponding adaptation algorithm to generate the certificate and
2267 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2268 group (i.e., the first match wins within each algorithm group). If no
2269 acl(s) match, the default mimicking action takes place.
2271 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2272 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2273 CONNECT request that carries a domain name. In all other cases (CONNECT
2274 to an IP address or an intercepted SSL connection), Squid cannot detect
2275 the domain mismatch at certificate generation time when
2276 bump-server-first is used.
2279 NAME: sslpassword_program
2282 LOC: Config.Program.ssl_password
2285 Specify a program used for entering SSL key passphrases
2286 when using encrypted SSL certificate keys. If not specified
2287 keys must either be unencrypted, or Squid started with the -N
2288 option to allow it to query interactively for the passphrase.
2290 The key file name is given as argument to the program allowing
2291 selection of the right password if you have multiple encrypted
2296 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2297 -----------------------------------------------------------------------------
2300 NAME: sslcrtd_program
2303 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2304 LOC: Ssl::TheConfig.ssl_crtd
2306 Specify the location and options of the executable for ssl_crtd process.
2307 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2308 For more information use:
2309 @DEFAULT_SSL_CRTD@ -h
2312 NAME: sslcrtd_children
2313 TYPE: HelperChildConfig
2315 DEFAULT: 32 startup=5 idle=1
2316 LOC: Ssl::TheConfig.ssl_crtdChildren
2318 The maximum number of processes spawn to service ssl server.
2319 The maximum this may be safely set to is 32.
2321 The startup= and idle= options allow some measure of skew in your
2326 Sets the minimum number of processes to spawn when Squid
2327 starts or reconfigures. When set to zero the first request will
2328 cause spawning of the first child process to handle it.
2330 Starting too few children temporary slows Squid under load while it
2331 tries to spawn enough additional processes to cope with traffic.
2335 Sets a minimum of how many processes Squid is to try and keep available
2336 at all times. When traffic begins to rise above what the existing
2337 processes can handle this many more will be spawned up to the maximum
2338 configured. A minimum setting of 1 is required.
2340 You must have at least one ssl_crtd process.
2344 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2345 -----------------------------------------------------------------------------
2353 To specify other caches in a hierarchy, use the format:
2355 cache_peer hostname type http-port icp-port [options]
2360 # hostname type port port options
2361 # -------------------- -------- ----- ----- -----------
2362 cache_peer parent.foo.net parent 3128 3130 default
2363 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2364 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2365 cache_peer example.com parent 80 0 default
2366 cache_peer cdn.example.com sibling 3128 0
2368 type: either 'parent', 'sibling', or 'multicast'.
2370 proxy-port: The port number where the peer accept HTTP requests.
2371 For other Squid proxies this is usually 3128
2372 For web servers this is usually 80
2374 icp-port: Used for querying neighbor caches about objects.
2375 Set to 0 if the peer does not support ICP or HTCP.
2376 See ICP and HTCP options below for additional details.
2379 ==== ICP OPTIONS ====
2381 You MUST also set icp_port and icp_access explicitly when using these options.
2382 The defaults will prevent peer traffic using ICP.
2385 no-query Disable ICP queries to this neighbor.
2388 Indicates the named peer is a member of a multicast group.
2389 ICP queries will not be sent directly to the peer, but ICP
2390 replies will be accepted from it.
2392 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2393 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2396 To only send ICP queries to this neighbor infrequently.
2397 This is used to keep the neighbor round trip time updated
2398 and is usually used in conjunction with weighted-round-robin.
2401 ==== HTCP OPTIONS ====
2403 You MUST also set htcp_port and htcp_access explicitly when using these options.
2404 The defaults will prevent peer traffic using HTCP.
2407 htcp Send HTCP, instead of ICP, queries to the neighbor.
2408 You probably also want to set the "icp-port" to 4827
2409 instead of 3130. This directive accepts a comma separated
2410 list of options described below.
2412 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2414 htcp=no-clr Send HTCP to the neighbor but without
2415 sending any CLR requests. This cannot be used with
2418 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2419 This cannot be used with no-clr.
2422 Send HTCP to the neighbor including CLRs but only when
2423 they do not result from PURGE requests.
2426 Forward any HTCP CLR requests this proxy receives to the peer.
2429 ==== PEER SELECTION METHODS ====
2431 The default peer selection method is ICP, with the first responding peer
2432 being used as source. These options can be used for better load balancing.
2435 default This is a parent cache which can be used as a "last-resort"
2436 if a peer cannot be located by any of the peer-selection methods.
2437 If specified more than once, only the first is used.
2439 round-robin Load-Balance parents which should be used in a round-robin
2440 fashion in the absence of any ICP queries.
2441 weight=N can be used to add bias.
2443 weighted-round-robin
2444 Load-Balance parents which should be used in a round-robin
2445 fashion with the frequency of each parent being based on the
2446 round trip time. Closer parents are used more often.
2447 Usually used for background-ping parents.
2448 weight=N can be used to add bias.
2450 carp Load-Balance parents which should be used as a CARP array.
2451 The requests will be distributed among the parents based on the
2452 CARP load balancing hash function based on their weight.
2454 userhash Load-balance parents based on the client proxy_auth or ident username.
2456 sourcehash Load-balance parents based on the client source IP.
2459 To be used only for cache peers of type "multicast".
2460 ALL members of this multicast group have "sibling"
2461 relationship with it, not "parent". This is to a multicast
2462 group when the requested object would be fetched only from
2463 a "parent" cache, anyway. It's useful, e.g., when
2464 configuring a pool of redundant Squid proxies, being
2465 members of the same multicast group.
2468 ==== PEER SELECTION OPTIONS ====
2470 weight=N use to affect the selection of a peer during any weighted
2471 peer-selection mechanisms.
2472 The weight must be an integer; default is 1,
2473 larger weights are favored more.
2474 This option does not affect parent selection if a peering
2475 protocol is not in use.
2477 basetime=N Specify a base amount to be subtracted from round trip
2479 It is subtracted before division by weight in calculating
2480 which parent to fectch from. If the rtt is less than the
2481 base time the rtt is set to a minimal value.
2483 ttl=N Specify a TTL to use when sending multicast ICP queries
2485 Only useful when sending to a multicast group.
2486 Because we don't accept ICP replies from random
2487 hosts, you must configure other group members as
2488 peers with the 'multicast-responder' option.
2490 no-delay To prevent access to this neighbor from influencing the
2493 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2494 enabled) for this host from the specified URL rather
2495 than the Squid default location.
2498 ==== CARP OPTIONS ====
2500 carp-key=key-specification
2501 use a different key than the full URL to hash against the peer.
2502 the key-specification is a comma-separated list of the keywords
2503 scheme, host, port, path, params
2504 Order is not important.
2506 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2508 originserver Causes this parent to be contacted as an origin server.
2509 Meant to be used in accelerator setups when the peer
2513 Set the Host header of requests forwarded to this peer.
2514 Useful in accelerator setups where the server (peer)
2515 expects a certain domain name but clients may request
2516 others. ie example.com or www.example.com
2518 no-digest Disable request of cache digests.
2521 Disables requesting ICMP RTT database (NetDB).
2524 ==== AUTHENTICATION OPTIONS ====
2527 If this is a personal/workgroup proxy and your parent
2528 requires proxy authentication.
2530 Note: The string can include URL escapes (i.e. %20 for
2531 spaces). This also means % must be written as %%.
2534 Send login details received from client to this peer.
2535 Both Proxy- and WWW-Authorization headers are passed
2536 without alteration to the peer.
2537 Authentication is not required by Squid for this to work.
2539 Note: This will pass any form of authentication but
2540 only Basic auth will work through a proxy unless the
2541 connection-auth options are also used.
2543 login=PASS Send login details received from client to this peer.
2544 Authentication is not required by this option.
2546 If there are no client-provided authentication headers
2547 to pass on, but username and password are available
2548 from an external ACL user= and password= result tags
2549 they may be sent instead.
2551 Note: To combine this with proxy_auth both proxies must
2552 share the same user database as HTTP only allows for
2553 a single login (one for proxy, one for origin server).
2554 Also be warned this will expose your users proxy
2555 password to the peer. USE WITH CAUTION
2558 Send the username to the upstream cache, but with a
2559 fixed password. This is meant to be used when the peer
2560 is in another administrative domain, but it is still
2561 needed to identify each user.
2562 The star can optionally be followed by some extra
2563 information which is added to the username. This can
2564 be used to identify this proxy to the peer, similar to
2565 the login=username:password option above.
2568 If this is a personal/workgroup proxy and your parent
2569 requires a secure proxy authentication.
2570 The first principal from the default keytab or defined by
2571 the environment variable KRB5_KTNAME will be used.
2573 WARNING: The connection may transmit requests from multiple
2574 clients. Negotiate often assumes end-to-end authentication
2575 and a single-client. Which is not strictly true here.
2577 login=NEGOTIATE:principal_name
2578 If this is a personal/workgroup proxy and your parent
2579 requires a secure proxy authentication.
2580 The principal principal_name from the default keytab or
2581 defined by the environment variable KRB5_KTNAME will be
2584 WARNING: The connection may transmit requests from multiple
2585 clients. Negotiate often assumes end-to-end authentication
2586 and a single-client. Which is not strictly true here.
2588 connection-auth=on|off
2589 Tell Squid that this peer does or not support Microsoft
2590 connection oriented authentication, and any such
2591 challenges received from there should be ignored.
2592 Default is auto to automatically determine the status
2596 ==== SSL / HTTPS / TLS OPTIONS ====
2598 ssl Encrypt connections to this peer with SSL/TLS.
2600 sslcert=/path/to/ssl/certificate
2601 A client SSL certificate to use when connecting to
2604 sslkey=/path/to/ssl/key
2605 The private SSL key corresponding to sslcert above.
2606 If 'sslkey' is not specified 'sslcert' is assumed to
2607 reference a combined file containing both the
2608 certificate and the key.
2610 sslversion=1|2|3|4|5|6
2611 The SSL version to use when connecting to this peer
2612 1 = automatic (default)
2619 sslcipher=... The list of valid SSL ciphers to use when connecting
2622 ssloptions=... Specify various SSL implementation options:
2624 NO_SSLv2 Disallow the use of SSLv2
2625 NO_SSLv3 Disallow the use of SSLv3
2626 NO_TLSv1 Disallow the use of TLSv1.0
2627 NO_TLSv1_1 Disallow the use of TLSv1.1
2628 NO_TLSv1_2 Disallow the use of TLSv1.2
2630 Always create a new key when using
2631 temporary/ephemeral DH key exchanges
2632 ALL Enable various bug workarounds
2633 suggested as "harmless" by OpenSSL
2634 Be warned that this reduces SSL/TLS
2635 strength to some attacks.
2637 See the OpenSSL SSL_CTX_set_options documentation for a
2640 sslcafile=... A file containing additional CA certificates to use
2641 when verifying the peer certificate.
2643 sslcapath=... A directory containing additional CA certificates to
2644 use when verifying the peer certificate.
2646 sslcrlfile=... A certificate revocation list file to use when
2647 verifying the peer certificate.
2649 sslflags=... Specify various flags modifying the SSL implementation:
2652 Accept certificates even if they fail to
2655 Don't use the default CA list built in
2658 Don't verify the peer certificate
2659 matches the server name
2661 ssldomain= The peer name as advertised in it's certificate.
2662 Used for verifying the correctness of the received peer
2663 certificate. If not specified the peer hostname will be
2667 Enable the "Front-End-Https: On" header needed when
2668 using Squid as a SSL frontend in front of Microsoft OWA.
2669 See MS KB document Q307347 for details on this header.
2670 If set to auto the header will only be added if the
2671 request is forwarded as a https:// URL.
2674 ==== GENERAL OPTIONS ====
2677 A peer-specific connect timeout.
2678 Also see the peer_connect_timeout directive.
2680 connect-fail-limit=N
2681 How many times connecting to a peer must fail before
2682 it is marked as down. Default is 10.
2684 allow-miss Disable Squid's use of only-if-cached when forwarding
2685 requests to siblings. This is primarily useful when
2686 icp_hit_stale is used by the sibling. To extensive use
2687 of this option may result in forwarding loops, and you
2688 should avoid having two-way peerings with this option.
2689 For example to deny peer usage on requests from peer
2690 by denying cache_peer_access if the source is a peer.
2692 max-conn=N Limit the amount of connections Squid may open to this
2695 name=xxx Unique name for the peer.
2696 Required if you have multiple peers on the same host
2697 but different ports.
2698 This name can be used in cache_peer_access and similar
2699 directives to dentify the peer.
2700 Can be used by outgoing access controls through the
2703 no-tproxy Do not use the client-spoof TPROXY support when forwarding
2704 requests to this peer. Use normal address selection instead.
2706 proxy-only objects fetched from the peer will not be stored locally.
2710 NAME: cache_peer_domain cache_host_domain
2715 Use to limit the domains for which a neighbor cache will be
2718 cache_peer_domain cache-host domain [domain ...]
2719 cache_peer_domain cache-host !domain
2721 For example, specifying
2723 cache_peer_domain parent.foo.net .edu
2725 has the effect such that UDP query packets are sent to
2726 'bigserver' only when the requested object exists on a
2727 server in the .edu domain. Prefixing the domainname
2728 with '!' means the cache will be queried for objects
2731 NOTE: * Any number of domains may be given for a cache-host,
2732 either on the same or separate lines.
2733 * When multiple domains are given for a particular
2734 cache-host, the first matched domain is applied.
2735 * Cache hosts with no domain restrictions are queried
2737 * There are no defaults.
2738 * There is also a 'cache_peer_access' tag in the ACL
2742 NAME: cache_peer_access
2747 Similar to 'cache_peer_domain' but provides more flexibility by
2750 cache_peer_access cache-host allow|deny [!]aclname ...
2752 The syntax is identical to 'http_access' and the other lists of
2753 ACL elements. See the comments for 'http_access' below, or
2754 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
2757 NAME: neighbor_type_domain
2758 TYPE: hostdomaintype
2762 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
2764 Modifying the neighbor type for specific domains is now
2765 possible. You can treat some domains differently than the
2766 default neighbor type specified on the 'cache_peer' line.
2767 Normally it should only be necessary to list domains which
2768 should be treated differently because the default neighbor type
2769 applies for hostnames which do not match domains listed here.
2772 cache_peer cache.foo.org parent 3128 3130
2773 neighbor_type_domain cache.foo.org sibling .com .net
2774 neighbor_type_domain cache.foo.org sibling .au .de
2777 NAME: dead_peer_timeout
2781 LOC: Config.Timeout.deadPeer
2783 This controls how long Squid waits to declare a peer cache
2784 as "dead." If there are no ICP replies received in this
2785 amount of time, Squid will declare the peer dead and not
2786 expect to receive any further ICP replies. However, it
2787 continues to send ICP queries, and will mark the peer as
2788 alive upon receipt of the first subsequent ICP reply.
2790 This timeout also affects when Squid expects to receive ICP
2791 replies from peers. If more than 'dead_peer' seconds have
2792 passed since the last ICP reply was received, Squid will not
2793 expect to receive an ICP reply on the next query. Thus, if
2794 your time between requests is greater than this timeout, you
2795 will see a lot of requests sent DIRECT to origin servers
2796 instead of to your parents.
2799 NAME: forward_max_tries
2802 LOC: Config.forward_max_tries
2804 Controls how many different forward paths Squid will try
2805 before giving up. See also forward_timeout.
2807 NOTE: connect_retries (default: none) can make each of these
2808 possible forwarding paths be tried multiple times.
2811 NAME: hierarchy_stoplist
2814 LOC: Config.hierarchy_stoplist
2816 A list of words which, if found in a URL, cause the object to
2817 be handled directly by this cache. In other words, use this
2818 to not query neighbor caches for certain objects. You may
2819 list this option multiple times.
2822 hierarchy_stoplist cgi-bin ?
2824 Note: never_direct overrides this option.
2828 MEMORY CACHE OPTIONS
2829 -----------------------------------------------------------------------------
2836 LOC: Config.memMaxSize
2838 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
2839 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
2840 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
2841 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
2843 'cache_mem' specifies the ideal amount of memory to be used
2845 * In-Transit objects
2847 * Negative-Cached objects
2849 Data for these objects are stored in 4 KB blocks. This
2850 parameter specifies the ideal upper limit on the total size of
2851 4 KB blocks allocated. In-Transit objects take the highest
2854 In-transit objects have priority over the others. When
2855 additional space is needed for incoming data, negative-cached
2856 and hot objects will be released. In other words, the
2857 negative-cached and hot objects will fill up any unused space
2858 not needed for in-transit objects.
2860 If circumstances require, this limit will be exceeded.
2861 Specifically, if your incoming request rate requires more than
2862 'cache_mem' of memory to hold in-transit objects, Squid will
2863 exceed this limit to satisfy the new requests. When the load
2864 decreases, blocks will be freed until the high-water mark is
2865 reached. Thereafter, blocks will be used to store hot
2868 If shared memory caching is enabled, Squid does not use the shared
2869 cache space for in-transit objects, but they still consume as much
2870 local memory as they need. For more details about the shared memory
2871 cache, see memory_cache_shared.
2874 NAME: maximum_object_size_in_memory
2878 LOC: Config.Store.maxInMemObjSize
2880 Objects greater than this size will not be attempted to kept in
2881 the memory cache. This should be set high enough to keep objects
2882 accessed frequently in memory to improve performance whilst low
2883 enough to keep larger objects from hoarding cache_mem.
2886 NAME: memory_cache_shared
2889 LOC: Config.memShared
2891 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
2893 Controls whether the memory cache is shared among SMP workers.
2895 The shared memory cache is meant to occupy cache_mem bytes and replace
2896 the non-shared memory cache, although some entities may still be
2897 cached locally by workers for now (e.g., internal and in-transit
2898 objects may be served from a local memory cache even if shared memory
2899 caching is enabled).
2901 By default, the memory cache is shared if and only if all of the
2902 following conditions are satisfied: Squid runs in SMP mode with
2903 multiple workers, cache_mem is positive, and Squid environment
2904 supports required IPC primitives (e.g., POSIX shared memory segments
2905 and GCC-style atomic operations).
2907 To avoid blocking locks, shared memory uses opportunistic algorithms
2908 that do not guarantee that every cachable entity that could have been
2909 shared among SMP workers will actually be shared.
2911 Currently, entities exceeding 32KB in size cannot be shared.
2914 NAME: memory_cache_mode
2919 Controls which objects to keep in the memory cache (cache_mem)
2921 always Keep most recently fetched objects in memory (default)
2923 disk Only disk cache hits are kept in memory, which means
2924 an object must first be cached on disk and then hit
2925 a second time before cached in memory.
2927 network Only objects fetched from network is kept in memory
2930 NAME: memory_replacement_policy
2932 LOC: Config.memPolicy
2935 The memory replacement policy parameter determines which
2936 objects are purged from memory when memory space is needed.
2938 See cache_replacement_policy for details.
2943 -----------------------------------------------------------------------------
2946 NAME: cache_replacement_policy
2948 LOC: Config.replPolicy
2951 The cache replacement policy parameter determines which
2952 objects are evicted (replaced) when disk space is needed.
2954 lru : Squid's original list based LRU policy
2955 heap GDSF : Greedy-Dual Size Frequency
2956 heap LFUDA: Least Frequently Used with Dynamic Aging
2957 heap LRU : LRU policy implemented using a heap
2959 Applies to any cache_dir lines listed below this.
2961 The LRU policies keeps recently referenced objects.
2963 The heap GDSF policy optimizes object hit rate by keeping smaller
2964 popular objects in cache so it has a better chance of getting a
2965 hit. It achieves a lower byte hit rate than LFUDA though since
2966 it evicts larger (possibly popular) objects.
2968 The heap LFUDA policy keeps popular objects in cache regardless of
2969 their size and thus optimizes byte hit rate at the expense of
2970 hit rate since one large, popular object will prevent many
2971 smaller, slightly less popular objects from being cached.
2973 Both policies utilize a dynamic aging mechanism that prevents
2974 cache pollution that can otherwise occur with frequency-based
2975 replacement policies.
2977 NOTE: if using the LFUDA replacement policy you should increase
2978 the value of maximum_object_size above its default of 4096 KB to
2979 to maximize the potential byte hit rate improvement of LFUDA.
2981 For more information about the GDSF and LFUDA cache replacement
2982 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
2983 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
2989 LOC: Config.cacheSwap
2993 cache_dir Type Directory-Name Fs-specific-data [options]
2995 You can specify multiple cache_dir lines to spread the
2996 cache among different disk partitions.
2998 Type specifies the kind of storage system to use. Only "ufs"
2999 is built by default. To enable any of the other storage systems
3000 see the --enable-storeio configure option.
3002 'Directory' is a top-level directory where cache swap
3003 files will be stored. If you want to use an entire disk
3004 for caching, this can be the mount-point directory.
3005 The directory must exist and be writable by the Squid
3006 process. Squid will NOT create this directory for you.
3008 In SMP configurations, cache_dir must not precede the workers option
3009 and should use configuration macros or conditionals to give each
3010 worker interested in disk caching a dedicated cache directory.
3014 "ufs" is the old well-known Squid storage format that has always
3017 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3019 'Mbytes' is the amount of disk space (MB) to use under this
3020 directory. The default is 100 MB. Change this to suit your
3021 configuration. Do NOT put the size of your disk drive here.
3022 Instead, if you want Squid to use the entire disk drive,
3023 subtract 20% and use that value.
3025 'L1' is the number of first-level subdirectories which
3026 will be created under the 'Directory'. The default is 16.
3028 'L2' is the number of second-level subdirectories which
3029 will be created under each first-level directory. The default
3032 The aufs store type:
3034 "aufs" uses the same storage format as "ufs", utilizing
3035 POSIX-threads to avoid blocking the main Squid process on
3036 disk-I/O. This was formerly known in Squid as async-io.
3038 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3040 see argument descriptions under ufs above
3042 The diskd store type:
3044 "diskd" uses the same storage format as "ufs", utilizing a
3045 separate process to avoid blocking the main Squid process on
3048 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3050 see argument descriptions under ufs above
3052 Q1 specifies the number of unacknowledged I/O requests when Squid
3053 stops opening new files. If this many messages are in the queues,
3054 Squid won't open new files. Default is 64
3056 Q2 specifies the number of unacknowledged messages when Squid
3057 starts blocking. If this many messages are in the queues,
3058 Squid blocks until it receives some replies. Default is 72
3060 When Q1 < Q2 (the default), the cache directory is optimized
3061 for lower response time at the expense of a decrease in hit
3062 ratio. If Q1 > Q2, the cache directory is optimized for
3063 higher hit ratio at the expense of an increase in response
3066 The rock store type:
3068 cache_dir rock Directory-Name Mbytes <max-size=bytes> [options]
3070 The Rock Store type is a database-style storage. All cached
3071 entries are stored in a "database" file, using fixed-size slots,
3072 one entry per slot. The database size is specified in MB. The
3073 slot size is specified in bytes using the max-size option. See
3074 below for more info on the max-size option.
3076 swap-timeout=msec: Squid will not start writing a miss to or
3077 reading a hit from disk if it estimates that the swap operation
3078 will take more than the specified number of milliseconds. By
3079 default and when set to zero, disables the disk I/O time limit
3080 enforcement. Ignored when using blocking I/O module because
3081 blocking synchronous I/O does not allow Squid to estimate the
3082 expected swap wait time.
3084 max-swap-rate=swaps/sec: Artificially limits disk access using
3085 the specified I/O rate limit. Swap out requests that
3086 would cause the average I/O rate to exceed the limit are
3087 delayed. Individual swap in requests (i.e., hits or reads) are
3088 not delayed, but they do contribute to measured swap rate and
3089 since they are placed in the same FIFO queue as swap out
3090 requests, they may wait longer if max-swap-rate is smaller.
3091 This is necessary on file systems that buffer "too
3092 many" writes and then start blocking Squid and other processes
3093 while committing those writes to disk. Usually used together
3094 with swap-timeout to avoid excessive delays and queue overflows
3095 when disk demand exceeds available disk "bandwidth". By default
3096 and when set to zero, disables the disk I/O rate limit
3097 enforcement. Currently supported by IpcIo module only.
3100 The coss store type:
3102 NP: COSS filesystem in Squid-3 has been deemed too unstable for
3103 production use and has thus been removed from this release.
3104 We hope that it can be made usable again soon.
3106 block-size=n defines the "block size" for COSS cache_dir's.
3107 Squid uses file numbers as block numbers. Since file numbers
3108 are limited to 24 bits, the block size determines the maximum
3109 size of the COSS partition. The default is 512 bytes, which
3110 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
3111 you should not change the coss block size after Squid
3112 has written some objects to the cache_dir.
3114 The coss file store has changed from 2.5. Now it uses a file
3115 called 'stripe' in the directory names in the config - and
3116 this will be created by squid -z.
3120 no-store, no new objects should be stored to this cache_dir
3122 min-size=n, refers to the min object size in bytes this cache_dir
3123 will accept. It's used to restrict a cache_dir to only store
3124 large objects (e.g. aufs) while other storedirs are optimized
3125 for smaller objects (e.g. COSS). Defaults to 0.
3127 max-size=n, refers to the max object size in bytes this cache_dir
3128 supports. It is used to select the cache_dir to store the object.
3129 Note: To make optimal use of the max-size limits you should order
3130 the cache_dir lines with the smallest max-size value first and the
3131 ones with no max-size specification last.
3133 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
3134 which can be changed with the --with-coss-membuf-size=N configure
3138 # Uncomment and adjust the following to add a disk cache directory.
3139 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3143 NAME: store_dir_select_algorithm
3145 LOC: Config.store_dir_select_algorithm
3148 Set this to 'round-robin' as an alternative.
3151 NAME: max_open_disk_fds
3153 LOC: Config.max_open_disk_fds
3156 To avoid having disk as the I/O bottleneck Squid can optionally
3157 bypass the on-disk cache if more than this amount of disk file
3158 descriptors are open.
3160 A value of 0 indicates no limit.
3163 NAME: minimum_object_size
3167 LOC: Config.Store.minObjectSize
3169 Objects smaller than this size will NOT be saved on disk. The
3170 value is specified in kilobytes, and the default is 0 KB, which
3171 means there is no minimum.
3174 NAME: maximum_object_size
3178 LOC: Config.Store.maxObjectSize
3180 Objects larger than this size will NOT be saved on disk. The
3181 value is specified in kilobytes, and the default is 4MB. If
3182 you wish to get a high BYTES hit ratio, you should probably
3183 increase this (one 32 MB object hit counts for 3200 10KB
3184 hits). If you wish to increase speed more than your want to
3185 save bandwidth you should leave this low.
3187 NOTE: if using the LFUDA replacement policy you should increase
3188 this value to maximize the byte hit rate improvement of LFUDA!
3189 See replacement_policy below for a discussion of this policy.
3192 NAME: cache_swap_low
3193 COMMENT: (percent, 0-100)
3196 LOC: Config.Swap.lowWaterMark
3199 NAME: cache_swap_high
3200 COMMENT: (percent, 0-100)
3203 LOC: Config.Swap.highWaterMark
3206 The low- and high-water marks for cache object replacement.
3207 Replacement begins when the swap (disk) usage is above the
3208 low-water mark and attempts to maintain utilization near the
3209 low-water mark. As swap utilization gets close to high-water
3210 mark object eviction becomes more aggressive. If utilization is
3211 close to the low-water mark less replacement is done each time.
3213 Defaults are 90% and 95%. If you have a large cache, 5% could be
3214 hundreds of MB. If this is the case you may wish to set these
3215 numbers closer together.
3220 -----------------------------------------------------------------------------
3230 logformat <name> <format specification>
3232 Defines an access log format.
3234 The <format specification> is a string with embedded % format codes
3236 % format codes all follow the same basic structure where all but
3237 the formatcode is optional. Output strings are automatically escaped
3238 as required according to their context and the output format
3239 modifiers are usually not needed, but can be specified if an explicit
3240 output format is desired.
3242 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3244 " output in quoted string format
3245 [ output in squid text log format as used by log_mime_hdrs
3246 # output in URL quoted format
3251 width minimum and/or maximum field width:
3252 [width_min][.width_max]
3253 When minimum starts with 0, the field is zero-padded.
3254 String values exceeding maximum width are truncated.
3256 {arg} argument such as header name etc
3260 % a literal % character
3261 sn Unique sequence number per log line entry
3262 err_code The ID of an error response served by Squid or
3263 a similar internal error identifier.
3264 err_detail Additional err_code-dependent error information.
3266 Connection related format codes:
3268 >a Client source IP address
3270 >p Client source port
3271 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3272 >la Local IP address the client connected to
3273 >lp Local port number the client connected to
3275 la Local listening IP address the client connection was connected to.
3276 lp Local listening port number the client connection was connected to.
3278 <a Server IP address of the last server or peer connection
3279 <A Server FQDN or peer name
3280 <p Server port number of the last server or peer connection
3281 <la Local IP address of the last server or peer connection
3282 <lp Local port number of the last server or peer connection
3284 Time related format codes:
3286 ts Seconds since epoch
3287 tu subsecond time (milliseconds)
3288 tl Local time. Optional strftime format argument
3289 default %d/%b/%Y:%H:%M:%S %z
3290 tg GMT time. Optional strftime format argument
3291 default %d/%b/%Y:%H:%M:%S %z
3292 tr Response time (milliseconds)
3293 dt Total time spent making DNS lookups (milliseconds)
3295 Access Control related format codes:
3297 et Tag returned by external acl
3298 ea Log string returned by external acl
3299 un User name (any available)
3300 ul User name from authentication
3301 ue User name from external acl helper
3302 ui User name from ident
3303 us User name from SSL
3305 HTTP related format codes:
3307 [http::]>h Original request header. Optional header name argument
3308 on the format header[:[separator]element]
3309 [http::]>ha The HTTP request headers after adaptation and redirection.
3310 Optional header name argument as for >h
3311 [http::]<h Reply header. Optional header name argument
3313 [http::]>Hs HTTP status code sent to the client
3314 [http::]<Hs HTTP status code received from the next hop
3315 [http::]<bs Number of HTTP-equivalent message body bytes
3316 received from the next hop, excluding chunked
3317 transfer encoding and control messages.
3318 Generated FTP/Gopher listings are treated as
3320 [http::]mt MIME content type
3321 [http::]rm Request method (GET/POST etc)
3322 [http::]>rm Request method from client
3323 [http::]<rm Request method sent to server or peer
3324 [http::]ru Request URL from client (historic, filtered for logging)
3325 [http::]>ru Request URL from client
3326 [http::]<ru Request URL sent to server or peer
3327 [http::]rp Request URL-Path excluding hostname
3328 [http::]>rp Request URL-Path excluding hostname from client
3329 [http::]<rp Request URL-Path excluding hostname sento to server or peer
3330 [http::]rv Request protocol version
3331 [http::]>rv Request protocol version from client
3332 [http::]<rv Request protocol version sent to server or peer
3333 [http::]<st Sent reply size including HTTP headers
3334 [http::]>st Received request size including HTTP headers. In the
3335 case of chunked requests the chunked encoding metadata
3337 [http::]>sh Received HTTP request headers size
3338 [http::]<sh Sent HTTP reply headers size
3339 [http::]st Request+Reply size including HTTP headers
3340 [http::]<sH Reply high offset sent
3341 [http::]<sS Upstream object size
3342 [http::]<pt Peer response time in milliseconds. The timer starts
3343 when the last request byte is sent to the next hop
3344 and stops when the last response byte is received.
3345 [http::]<tt Total server-side time in milliseconds. The timer
3346 starts with the first connect request (or write I/O)
3347 sent to the first selected peer. The timer stops
3348 with the last I/O with the last peer.
3350 Squid handling related format codes:
3352 Ss Squid request status (TCP_MISS etc)
3353 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3355 SSL-related format codes:
3357 ssl::bump_mode SslBump decision for the transaction:
3359 For CONNECT requests that initiated bumping of
3360 a connection and for any request received on
3361 an already bumped connection, Squid logs the
3362 corresponding SslBump mode ("server-first" or
3363 "client-first"). See the ssl_bump option for
3364 more information about these modes.
3366 A "none" token is logged for requests that
3367 triggered "ssl_bump" ACL evaluation matching
3368 either a "none" rule or no rules at all.
3370 In all other cases, a single dash ("-") is
3373 If ICAP is enabled, the following code becomes available (as
3374 well as ICAP log codes documented with the icap_log option):
3376 icap::tt Total ICAP processing time for the HTTP
3377 transaction. The timer ticks when ICAP
3378 ACLs are checked and when ICAP
3379 transaction is in progress.
3381 If adaptation is enabled the following three codes become available:
3383 adapt::<last_h The header of the last ICAP response or
3384 meta-information from the last eCAP
3385 transaction related to the HTTP transaction.
3386 Like <h, accepts an optional header name
3389 adapt::sum_trs Summed adaptation transaction response
3390 times recorded as a comma-separated list in
3391 the order of transaction start time. Each time
3392 value is recorded as an integer number,
3393 representing response time of one or more
3394 adaptation (ICAP or eCAP) transaction in
3395 milliseconds. When a failed transaction is
3396 being retried or repeated, its time is not
3397 logged individually but added to the
3398 replacement (next) transaction. See also:
3401 adapt::all_trs All adaptation transaction response times.
3402 Same as adaptation_strs but response times of
3403 individual transactions are never added
3404 together. Instead, all transaction response
3405 times are recorded individually.
3407 You can prefix adapt::*_trs format codes with adaptation
3408 service name in curly braces to record response time(s) specific
3409 to that service. For example: %{my_service}adapt::sum_trs
3411 If SSL is enabled, the following formating codes become available:
3413 %ssl::>cert_subject The Subject field of the received client
3414 SSL certificate or a dash ('-') if Squid has
3415 received an invalid/malformed certificate or
3416 no certificate at all. Consider encoding the
3417 logged value because Subject often has spaces.
3419 %ssl::>cert_issuer The Issuer field of the received client
3420 SSL certificate or a dash ('-') if Squid has
3421 received an invalid/malformed certificate or
3422 no certificate at all. Consider encoding the
3423 logged value because Issuer often has spaces.
3425 The default formats available (which do not need re-defining) are:
3427 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3428 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3429 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3430 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3431 logformat useragent %>a [%tl] "%{User-Agent}>h"
3433 NOTE: When the log_mime_hdrs directive is set to ON.
3434 The squid, common and combined formats have a safely encoded copy
3435 of the mime headers appended to each line within a pair of brackets.
3437 NOTE: The common and combined formats are not quite true to the Apache definition.
3438 The logs from Squid contain an extra status and hierarchy code appended.
3442 NAME: access_log cache_access_log
3444 LOC: Config.Log.accesslogs
3445 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3447 These files log client request activities. Has a line every HTTP or
3448 ICP request. The format is:
3449 access_log <module>:<place> [<logformat name> [acl acl ...]]
3450 access_log none [acl acl ...]]
3452 Will log to the specified module:place using the specified format (which
3453 must be defined in a logformat directive) those entries which match
3454 ALL the acl's specified (which must be defined in acl clauses).
3455 If no acl is specified, all requests will be logged to this destination.
3457 ===== Modules Currently available =====
3459 none Do not log any requests matching these ACL.
3460 Do not specify Place or logformat name.
3462 stdio Write each log line to disk immediately at the completion of
3464 Place: the filename and path to be written.
3466 daemon Very similar to stdio. But instead of writing to disk the log
3467 line is passed to a daemon helper for asychronous handling instead.
3468 Place: varies depending on the daemon.
3470 log_file_daemon Place: the file name and path to be written.
3472 syslog To log each request via syslog facility.
3473 Place: The syslog facility and priority level for these entries.
3474 Place Format: facility.priority
3476 where facility could be any of:
3477 authpriv, daemon, local0 ... local7 or user.
3479 And priority could be any of:
3480 err, warning, notice, info, debug.
3482 udp To send each log line as text data to a UDP receiver.
3483 Place: The destination host name or IP and port.
3484 Place Format: //host:port
3486 tcp To send each log line as text data to a TCP receiver.
3487 Place: The destination host name or IP and port.
3488 Place Format: //host:port
3491 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3497 LOC: Config.Log.icaplogs
3500 ICAP log files record ICAP transaction summaries, one line per
3503 The icap_log option format is:
3504 icap_log <filepath> [<logformat name> [acl acl ...]]
3505 icap_log none [acl acl ...]]
3507 Please see access_log option documentation for details. The two
3508 kinds of logs share the overall configuration approach and many
3511 ICAP processing of a single HTTP message or transaction may
3512 require multiple ICAP transactions. In such cases, multiple
3513 ICAP transaction log lines will correspond to a single access
3516 ICAP log uses logformat codes that make sense for an ICAP
3517 transaction. Header-related codes are applied to the HTTP header
3518 embedded in an ICAP server response, with the following caveats:
3519 For REQMOD, there is no HTTP response header unless the ICAP
3520 server performed request satisfaction. For RESPMOD, the HTTP
3521 request header is the header sent to the ICAP server. For
3522 OPTIONS, there are no HTTP headers.
3524 The following format codes are also available for ICAP logs:
3526 icap::<A ICAP server IP address. Similar to <A.
3528 icap::<service_name ICAP service name from the icap_service
3529 option in Squid configuration file.
3531 icap::ru ICAP Request-URI. Similar to ru.
3533 icap::rm ICAP request method (REQMOD, RESPMOD, or
3534 OPTIONS). Similar to existing rm.
3536 icap::>st Bytes sent to the ICAP server (TCP payload
3537 only; i.e., what Squid writes to the socket).
3539 icap::<st Bytes received from the ICAP server (TCP
3540 payload only; i.e., what Squid reads from
3543 icap::<bs Number of message body bytes received from the
3544 ICAP server. ICAP message body, if any, usually
3545 includes encapsulated HTTP message headers and
3546 possibly encapsulated HTTP message body. The
3547 HTTP body part is dechunked before its size is
3550 icap::tr Transaction response time (in
3551 milliseconds). The timer starts when
3552 the ICAP transaction is created and
3553 stops when the transaction is completed.
3556 icap::tio Transaction I/O time (in milliseconds). The
3557 timer starts when the first ICAP request
3558 byte is scheduled for sending. The timers
3559 stops when the last byte of the ICAP response
3562 icap::to Transaction outcome: ICAP_ERR* for all
3563 transaction errors, ICAP_OPT for OPTION
3564 transactions, ICAP_ECHO for 204
3565 responses, ICAP_MOD for message
3566 modification, and ICAP_SAT for request
3567 satisfaction. Similar to Ss.
3569 icap::Hs ICAP response status code. Similar to Hs.
3571 icap::>h ICAP request header(s). Similar to >h.
3573 icap::<h ICAP response header(s). Similar to <h.
3575 The default ICAP log format, which can be used without an explicit
3576 definition, is called icap_squid:
3578 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3580 See also: logformat, log_icap, and %adapt::<last_h
3583 NAME: logfile_daemon
3585 DEFAULT: @DEFAULT_LOGFILED@
3586 LOC: Log::TheConfig.logfile_daemon
3588 Specify the path to the logfile-writing daemon. This daemon is
3589 used to write the access and store logs, if configured.
3591 Squid sends a number of commands to the log daemon:
3592 L<data>\n - logfile data
3597 r<n>\n - set rotate count to <n>
3598 b<n>\n - 1 = buffer output, 0 = don't buffer output
3600 No responses is expected.
3605 LOC: Config.accessList.log
3607 COMMENT: allow|deny acl acl...
3609 This options allows you to control which requests gets logged
3610 to access.log (see access_log directive). Requests denied for
3611 logging will also not be accounted for in performance counters.
3613 This clause only supports fast acl types.
3614 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3620 LOC: Config.accessList.icap
3623 This options allows you to control which requests get logged
3624 to icap.log. See the icap_log directive for ICAP log details.
3627 NAME: cache_store_log
3630 LOC: Config.Log.store
3632 Logs the activities of the storage manager. Shows which
3633 objects are ejected from the cache, and which objects are
3634 saved and for how long. To disable, enter "none" or remove the line.
3635 There are not really utilities to analyze this data, so you can safely
3639 cache_store_log @DEFAULT_STORE_LOG@
3642 NAME: cache_swap_state cache_swap_log
3644 LOC: Config.Log.swap
3647 Location for the cache "swap.state" file. This index file holds
3648 the metadata of objects saved on disk. It is used to rebuild
3649 the cache during startup. Normally this file resides in each
3650 'cache_dir' directory, but you may specify an alternate
3651 pathname here. Note you must give a full filename, not just
3652 a directory. Since this is the index for the whole object
3653 list you CANNOT periodically rotate it!
3655 If %s can be used in the file name it will be replaced with a
3656 a representation of the cache_dir name where each / is replaced
3657 with '.'. This is needed to allow adding/removing cache_dir
3658 lines when cache_swap_log is being used.
3660 If have more than one 'cache_dir', and %s is not used in the name
3661 these swap logs will have names such as:
3667 The numbered extension (which is added automatically)
3668 corresponds to the order of the 'cache_dir' lines in this
3669 configuration file. If you change the order of the 'cache_dir'
3670 lines in this file, these index files will NOT correspond to
3671 the correct 'cache_dir' entry (unless you manually rename
3672 them). We recommend you do NOT use this option. It is
3673 better to keep these index files in each 'cache_dir' directory.
3676 NAME: logfile_rotate
3679 LOC: Config.Log.rotateNumber
3681 Specifies the number of logfile rotations to make when you
3682 type 'squid -k rotate'. The default is 10, which will rotate
3683 with extensions 0 through 9. Setting logfile_rotate to 0 will
3684 disable the file name rotation, but the logfiles are still closed
3685 and re-opened. This will enable you to rename the logfiles
3686 yourself just before sending the rotate signal.
3688 Note, the 'squid -k rotate' command normally sends a USR1
3689 signal to the running squid process. In certain situations
3690 (e.g. on Linux with Async I/O), USR1 is used for other
3691 purposes, so -k rotate uses another signal. It is best to get
3692 in the habit of using 'squid -k rotate' instead of 'kill -USR1
3695 Note, from Squid-3.1 this option has no effect on the cache.log,
3696 that log can be rotated separately by using debug_options
3699 NAME: emulate_httpd_log
3702 Replace this with an access_log directive using the format 'common' or 'combined'.
3705 NAME: log_ip_on_direct
3708 Remove this option from your config. To log server or peer names use %<A in the log format.
3713 DEFAULT: @DEFAULT_MIME_TABLE@
3714 LOC: Config.mimeTablePathname
3716 Pathname to Squid's MIME table. You shouldn't need to change
3717 this, but the default file contains examples and formatting
3718 information if you do.
3724 LOC: Config.onoff.log_mime_hdrs
3727 The Cache can record both the request and the response MIME
3728 headers for each HTTP transaction. The headers are encoded
3729 safely and will appear as two bracketed fields at the end of
3730 the access log (for either the native or httpd-emulated log
3731 formats). To enable this logging set log_mime_hdrs to 'on'.
3737 Replace this with an access_log directive using the format 'useragent'.
3740 NAME: referer_log referrer_log
3743 Replace this with an access_log directive using the format 'referrer'.
3748 DEFAULT: @DEFAULT_PID_FILE@
3749 LOC: Config.pidFilename
3751 A filename to write the process-id to. To disable, enter "none".
3757 Remove this option from your config. To log FQDN use %>A in the log format.
3760 NAME: client_netmask
3762 LOC: Config.Addrs.client_netmask
3765 A netmask for client addresses in logfiles and cachemgr output.
3766 Change this to protect the privacy of your cache clients.
3767 A netmask of 255.255.255.0 will log all IP's in that range with
3768 the last digit set to '0'.
3774 Use a regular access.log with ACL limiting it to MISS events.
3777 NAME: strip_query_terms
3779 LOC: Config.onoff.strip_query_terms
3782 By default, Squid strips query terms from requested URLs before
3783 logging. This protects your user's privacy.
3790 LOC: Config.onoff.buffered_logs
3792 cache.log log file is written with stdio functions, and as such
3793 it can be buffered or unbuffered. By default it will be unbuffered.
3794 Buffering it can speed up the writing slightly (though you are
3795 unlikely to need to worry unless you run with tons of debugging
3796 enabled in which case performance will suffer badly anyway..).
3799 NAME: netdb_filename
3801 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
3802 LOC: Config.netdbFilename
3805 A filename where Squid stores it's netdb state between restarts.
3806 To disable, enter "none".
3810 OPTIONS FOR TROUBLESHOOTING
3811 -----------------------------------------------------------------------------
3816 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
3817 LOC: Debug::cache_log
3819 Cache logging file. This is where general information about
3820 your cache's behavior goes. You can increase the amount of data
3821 logged to this file and how often its rotated with "debug_options"
3827 LOC: Debug::debugOptions
3829 Logging options are set as section,level where each source file
3830 is assigned a unique section. Lower levels result in less
3831 output, Full debugging (level 9) can result in a very large
3832 log file, so be careful.
3834 The magic word "ALL" sets debugging levels for all sections.
3835 We recommend normally running with "ALL,1".
3837 The rotate=N option can be used to keep more or less of these logs
3838 than would otherwise be kept by logfile_rotate.
3839 For most uses a single log should be enough to monitor current
3840 events affecting Squid.
3845 LOC: Config.coredump_dir
3846 DEFAULT_IF_NONE: none
3848 By default Squid leaves core files in the directory from where
3849 it was started. If you set 'coredump_dir' to a directory
3850 that exists, Squid will chdir() to that directory at startup
3851 and coredump files will be left there.
3855 # Leave coredumps in the first cache dir
3856 coredump_dir @DEFAULT_SWAP_DIR@
3862 OPTIONS FOR FTP GATEWAYING
3863 -----------------------------------------------------------------------------
3869 LOC: Config.Ftp.anon_user
3871 If you want the anonymous login password to be more informative
3872 (and enable the use of picky ftp servers), set this to something
3873 reasonable for your domain, like wwwuser@somewhere.net
3875 The reason why this is domainless by default is the
3876 request can be made on the behalf of a user in any domain,
3877 depending on how the cache is used.
3878 Some ftp server also validate the email address is valid
3879 (for example perl.com).
3885 LOC: Config.Ftp.passive
3887 If your firewall does not allow Squid to use passive
3888 connections, turn off this option.
3890 Use of ftp_epsv_all option requires this to be ON.
3896 LOC: Config.Ftp.epsv_all
3898 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
3900 NATs may be able to put the connection on a "fast path" through the
3901 translator, as the EPRT command will never be used and therefore,
3902 translation of the data portion of the segments will never be needed.
3904 When a client only expects to do two-way FTP transfers this may be
3906 If squid finds that it must do a three-way FTP transfer after issuing
3907 an EPSV ALL command, the FTP session will fail.
3909 If you have any doubts about this option do not use it.
3910 Squid will nicely attempt all other connection methods.
3912 Requires ftp_passive to be ON (default) for any effect.
3918 LOC: Config.Ftp.epsv
3920 FTP Protocol extensions permit the use of a special "EPSV" command.
3922 NATs may be able to put the connection on a "fast path" through the
3923 translator using EPSV, as the EPRT command will never be used
3924 and therefore, translation of the data portion of the segments
3925 will never be needed.
3927 Turning this OFF will prevent EPSV being attempted.
3928 WARNING: Doing so will convert Squid back to the old behavior with all
3929 the related problems with external NAT devices/layers.
3931 Requires ftp_passive to be ON (default) for any effect.
3937 LOC: Config.Ftp.eprt
3939 FTP Protocol extensions permit the use of a special "EPRT" command.
3941 This extension provides a protocol neutral alternative to the
3942 IPv4-only PORT command. When supported it enables active FTP data
3943 channels over IPv6 and efficient NAT handling.
3945 Turning this OFF will prevent EPRT being attempted and will skip
3946 straight to using PORT for IPv4 servers.
3948 Some devices are known to not handle this extension correctly and
3949 may result in crashes. Devices which suport EPRT enough to fail
3950 cleanly will result in Squid attempting PORT anyway. This directive
3951 should only be disabled when EPRT results in device failures.
3953 WARNING: Doing so will convert Squid back to the old behavior with all
3954 the related problems with external NAT devices/layers and IPv4-only FTP.
3957 NAME: ftp_sanitycheck
3960 LOC: Config.Ftp.sanitycheck
3962 For security and data integrity reasons Squid by default performs
3963 sanity checks of the addresses of FTP data connections ensure the
3964 data connection is to the requested server. If you need to allow
3965 FTP connections to servers using another IP address for the data
3966 connection turn this off.
3969 NAME: ftp_telnet_protocol
3972 LOC: Config.Ftp.telnet
3974 The FTP protocol is officially defined to use the telnet protocol
3975 as transport channel for the control connection. However, many
3976 implementations are broken and does not respect this aspect of
3979 If you have trouble accessing files with ASCII code 255 in the
3980 path or similar problems involving this ASCII code you can
3981 try setting this directive to off. If that helps, report to the
3982 operator of the FTP server in question that their FTP server
3983 is broken and does not follow the FTP standard.
3987 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
3988 -----------------------------------------------------------------------------
3993 DEFAULT: @DEFAULT_DISKD@
3994 LOC: Config.Program.diskd
3996 Specify the location of the diskd executable.
3997 Note this is only useful if you have compiled in
3998 diskd as one of the store io modules.
4001 NAME: unlinkd_program
4004 DEFAULT: @DEFAULT_UNLINKD@
4005 LOC: Config.Program.unlinkd
4007 Specify the location of the executable for file deletion process.
4010 NAME: pinger_program
4012 DEFAULT: @DEFAULT_PINGER@
4013 LOC: Config.pinger.program
4016 Specify the location of the executable for the pinger process.
4022 LOC: Config.pinger.enable
4025 Control whether the pinger is active at run-time.
4026 Enables turning ICMP pinger on and off with a simple
4027 squid -k reconfigure.
4032 OPTIONS FOR URL REWRITING
4033 -----------------------------------------------------------------------------
4036 NAME: url_rewrite_program redirect_program
4038 LOC: Config.Program.redirect
4041 Specify the location of the executable URL rewriter to use.
4042 Since they can perform almost any function there isn't one included.
4044 For each requested URL, the rewriter will receive on line with the format
4046 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
4048 In the future, the rewriter interface will be extended with
4049 key=value pairs ("kvpairs" shown above). Rewriter programs
4050 should be prepared to receive and possibly ignore additional
4051 whitespace-separated tokens on each input line.
4053 And the rewriter may return a rewritten URL. The other components of
4054 the request line does not need to be returned (ignored if they are).
4056 The rewriter can also indicate that a client-side redirect should
4057 be performed to the new URL. This is done by prefixing the returned
4058 URL with "301:" (moved permanently) or 302: (moved temporarily), etc.
4060 By default, a URL rewriter is not used.
4063 NAME: url_rewrite_children redirect_children
4064 TYPE: HelperChildConfig
4065 DEFAULT: 20 startup=0 idle=1 concurrency=0
4066 LOC: Config.redirectChildren
4068 The maximum number of redirector processes to spawn. If you limit
4069 it too few Squid will have to wait for them to process a backlog of
4070 URLs, slowing it down. If you allow too many they will use RAM
4071 and other system resources noticably.
4073 The startup= and idle= options allow some measure of skew in your
4078 Sets a minimum of how many processes are to be spawned when Squid
4079 starts or reconfigures. When set to zero the first request will
4080 cause spawning of the first child process to handle it.
4082 Starting too few will cause an initial slowdown in traffic as Squid
4083 attempts to simultaneously spawn enough processes to cope.
4087 Sets a minimum of how many processes Squid is to try and keep available
4088 at all times. When traffic begins to rise above what the existing
4089 processes can handle this many more will be spawned up to the maximum
4090 configured. A minimum setting of 1 is required.
4094 The number of requests each redirector helper can handle in
4095 parallel. Defaults to 0 which indicates the redirector
4096 is a old-style single threaded redirector.
4098 When this directive is set to a value >= 1 then the protocol
4099 used to communicate with the helper is modified to include
4100 a request ID in front of the request/response. The request
4101 ID from the request must be echoed back with the response
4105 NAME: url_rewrite_host_header redirect_rewrites_host_header
4108 LOC: Config.onoff.redir_rewrites_host
4110 To preserve same-origin security policies in browsers and
4111 prevent Host: header forgery by redirectors Squid rewrites
4112 any Host: header in redirected requests.
4114 If you are running an accelerator this may not be a wanted
4115 effect of a redirector. This directive enables you disable
4116 Host: alteration in reverse-proxy traffic.
4118 WARNING: Entries are cached on the result of the URL rewriting
4119 process, so be careful if you have domain-virtual hosts.
4121 WARNING: Squid and other software verifies the URL and Host
4122 are matching, so be careful not to relay through other proxies
4123 or inspecting firewalls with this disabled.
4126 NAME: url_rewrite_access redirector_access
4129 LOC: Config.accessList.redirector
4131 If defined, this access list specifies which requests are
4132 sent to the redirector processes. By default all requests
4135 This clause supports both fast and slow acl types.
4136 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4139 NAME: url_rewrite_bypass redirector_bypass
4141 LOC: Config.onoff.redirector_bypass
4144 When this is 'on', a request will not go through the
4145 redirector if all redirectors are busy. If this is 'off'
4146 and the redirector queue grows too large, Squid will exit
4147 with a FATAL error and ask you to increase the number of
4148 redirectors. You should only enable this if the redirectors
4149 are not critical to your caching system. If you use
4150 redirectors for access control, and you enable this option,
4151 users may have access to pages they should not
4152 be allowed to request.
4156 OPTIONS FOR TUNING THE CACHE
4157 -----------------------------------------------------------------------------
4160 NAME: cache no_cache
4163 LOC: Config.accessList.noCache
4165 A list of ACL elements which, if matched and denied, cause the request to
4166 not be satisfied from the cache and the reply to not be cached.
4167 In other words, use this to force certain objects to never be cached.
4169 You must use the words 'allow' or 'deny' to indicate whether items
4170 matching the ACL should be allowed or denied into the cache.
4172 Default is to allow all to be cached.
4174 This clause supports both fast and slow acl types.
4175 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4181 LOC: Config.maxStale
4184 This option puts an upper limit on how stale content Squid
4185 will serve from the cache if cache validation fails.
4186 Can be overriden by the refresh_pattern max-stale option.
4189 NAME: refresh_pattern
4190 TYPE: refreshpattern
4194 usage: refresh_pattern [-i] regex min percent max [options]
4196 By default, regular expressions are CASE-SENSITIVE. To make
4197 them case-insensitive, use the -i option.
4199 'Min' is the time (in minutes) an object without an explicit
4200 expiry time should be considered fresh. The recommended
4201 value is 0, any higher values may cause dynamic applications
4202 to be erroneously cached unless the application designer
4203 has taken the appropriate actions.
4205 'Percent' is a percentage of the objects age (time since last
4206 modification age) an object without explicit expiry time
4207 will be considered fresh.
4209 'Max' is an upper limit on how long objects without an explicit
4210 expiry time will be considered fresh.
4212 options: override-expire
4218 ignore-must-revalidate
4225 override-expire enforces min age even if the server
4226 sent an explicit expiry time (e.g., with the
4227 Expires: header or Cache-Control: max-age). Doing this
4228 VIOLATES the HTTP standard. Enabling this feature
4229 could make you liable for problems which it causes.
4231 Note: override-expire does not enforce staleness - it only extends
4232 freshness / min. If the server returns a Expires time which
4233 is longer than your max time, Squid will still consider
4234 the object fresh for that period of time.
4236 override-lastmod enforces min age even on objects
4237 that were modified recently.
4239 reload-into-ims changes client no-cache or ``reload''
4240 to If-Modified-Since requests. Doing this VIOLATES the
4241 HTTP standard. Enabling this feature could make you
4242 liable for problems which it causes.
4244 ignore-reload ignores a client no-cache or ``reload''
4245 header. Doing this VIOLATES the HTTP standard. Enabling
4246 this feature could make you liable for problems which
4249 ignore-no-cache ignores any ``Pragma: no-cache'' and
4250 ``Cache-control: no-cache'' headers received from a server.
4251 The HTTP RFC never allows the use of this (Pragma) header
4252 from a server, only a client, though plenty of servers
4255 ignore-no-store ignores any ``Cache-control: no-store''
4256 headers received from a server. Doing this VIOLATES
4257 the HTTP standard. Enabling this feature could make you
4258 liable for problems which it causes.
4260 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
4261 headers received from a server. Doing this VIOLATES
4262 the HTTP standard. Enabling this feature could make you
4263 liable for problems which it causes.
4265 ignore-private ignores any ``Cache-control: private''
4266 headers received from a server. Doing this VIOLATES
4267 the HTTP standard. Enabling this feature could make you
4268 liable for problems which it causes.
4270 ignore-auth caches responses to requests with authorization,
4271 as if the originserver had sent ``Cache-control: public''
4272 in the response header. Doing this VIOLATES the HTTP standard.
4273 Enabling this feature could make you liable for problems which
4276 refresh-ims causes squid to contact the origin server
4277 when a client issues an If-Modified-Since request. This
4278 ensures that the client will receive an updated version
4279 if one is available.
4281 store-stale stores responses even if they don't have explicit
4282 freshness or a validator (i.e., Last-Modified or an ETag)
4283 present, or if they're already stale. By default, Squid will
4284 not cache such responses because they usually can't be
4285 reused. Note that such responses will be stale by default.
4287 max-stale=NN provide a maximum staleness factor. Squid won't
4288 serve objects more stale than this even if it failed to
4289 validate the object. Default: use the max_stale global limit.
4291 Basically a cached object is:
4293 FRESH if expires < now, else STALE
4295 FRESH if lm-factor < percent, else STALE
4299 The refresh_pattern lines are checked in the order listed here.
4300 The first entry which matches is used. If none of the entries
4301 match the default will be used.
4303 Note, you must uncomment all the default lines if you want
4304 to change one. The default setting is only active if none is
4309 # Add any of your own refresh_pattern entries above these.
4310 refresh_pattern ^ftp: 1440 20% 10080
4311 refresh_pattern ^gopher: 1440 0% 1440
4312 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
4313 refresh_pattern . 0 20% 4320
4317 NAME: quick_abort_min
4321 LOC: Config.quickAbort.min
4324 NAME: quick_abort_max
4328 LOC: Config.quickAbort.max
4331 NAME: quick_abort_pct
4335 LOC: Config.quickAbort.pct
4337 The cache by default continues downloading aborted requests
4338 which are almost completed (less than 16 KB remaining). This
4339 may be undesirable on slow (e.g. SLIP) links and/or very busy
4340 caches. Impatient users may tie up file descriptors and
4341 bandwidth by repeatedly requesting and immediately aborting
4344 When the user aborts a request, Squid will check the
4345 quick_abort values to the amount of data transfered until
4348 If the transfer has less than 'quick_abort_min' KB remaining,
4349 it will finish the retrieval.
4351 If the transfer has more than 'quick_abort_max' KB remaining,
4352 it will abort the retrieval.
4354 If more than 'quick_abort_pct' of the transfer has completed,
4355 it will finish the retrieval.
4357 If you do not want any retrieval to continue after the client
4358 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
4361 If you want retrievals to always continue if they are being
4362 cached set 'quick_abort_min' to '-1 KB'.
4365 NAME: read_ahead_gap
4366 COMMENT: buffer-size
4368 LOC: Config.readAheadGap
4371 The amount of data the cache will buffer ahead of what has been
4372 sent to the client when retrieving an object from another server.
4376 IFDEF: USE_HTTP_VIOLATIONS
4379 LOC: Config.negativeTtl
4382 Set the Default Time-to-Live (TTL) for failed requests.
4383 Certain types of failures (such as "connection refused" and
4384 "404 Not Found") are able to be negatively-cached for a short time.
4385 Modern web servers should provide Expires: header, however if they
4386 do not this can provide a minimum TTL.
4387 The default is not to cache errors with unknown expiry details.
4389 Note that this is different from negative caching of DNS lookups.
4391 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4392 this feature could make you liable for problems which it
4396 NAME: positive_dns_ttl
4399 LOC: Config.positiveDnsTtl
4402 Upper limit on how long Squid will cache positive DNS responses.
4403 Default is 6 hours (360 minutes). This directive must be set
4404 larger than negative_dns_ttl.
4407 NAME: negative_dns_ttl
4410 LOC: Config.negativeDnsTtl
4413 Time-to-Live (TTL) for negative caching of failed DNS lookups.
4414 This also sets the lower cache limit on positive lookups.
4415 Minimum value is 1 second, and it is not recommendable to go
4416 much below 10 seconds.
4419 NAME: range_offset_limit
4420 COMMENT: size [acl acl...]
4422 LOC: Config.rangeOffsetLimit
4425 usage: (size) [units] [[!]aclname]
4427 Sets an upper limit on how far (number of bytes) into the file
4428 a Range request may be to cause Squid to prefetch the whole file.
4429 If beyond this limit, Squid forwards the Range request as it is and
4430 the result is NOT cached.
4432 This is to stop a far ahead range request (lets say start at 17MB)
4433 from making Squid fetch the whole object up to that point before
4434 sending anything to the client.
4436 Multiple range_offset_limit lines may be specified, and they will
4437 be searched from top to bottom on each request until a match is found.
4438 The first match found will be used. If no line matches a request, the
4439 default limit of 0 bytes will be used.
4441 'size' is the limit specified as a number of units.
4443 'units' specifies whether to use bytes, KB, MB, etc.
4444 If no units are specified bytes are assumed.
4446 A size of 0 causes Squid to never fetch more than the
4447 client requested. (default)
4449 A size of 'none' causes Squid to always fetch the object from the
4450 beginning so it may cache the result. (2.0 style)
4452 'aclname' is the name of a defined ACL.
4454 NP: Using 'none' as the byte value here will override any quick_abort settings
4455 that may otherwise apply to the range request. The range request will
4456 be fully fetched from start to finish regardless of the client
4457 actions. This affects bandwidth usage.
4460 NAME: minimum_expiry_time
4463 LOC: Config.minimum_expiry_time
4466 The minimum caching time according to (Expires - Date)
4467 Headers Squid honors if the object can't be revalidated
4468 defaults to 60 seconds. In reverse proxy environments it
4469 might be desirable to honor shorter object lifetimes. It
4470 is most likely better to make your server return a
4471 meaningful Last-Modified header however. In ESI environments
4472 where page fragments often have short lifetimes, this will
4473 often be best set to 0.
4476 NAME: store_avg_object_size
4480 LOC: Config.Store.avgObjectSize
4482 Average object size, used to estimate number of objects your
4483 cache can hold. The default is 13 KB.
4486 NAME: store_objects_per_bucket
4489 LOC: Config.Store.objectsPerBucket
4491 Target number of objects per bucket in the store hash table.
4492 Lowering this value increases the total number of buckets and
4493 also the storage maintenance rate. The default is 20.
4498 -----------------------------------------------------------------------------
4501 NAME: request_header_max_size
4505 LOC: Config.maxRequestHeaderSize
4507 This specifies the maximum size for HTTP headers in a request.
4508 Request headers are usually relatively small (about 512 bytes).
4509 Placing a limit on the request header size will catch certain
4510 bugs (for example with persistent connections) and possibly
4511 buffer-overflow or denial-of-service attacks.
4514 NAME: reply_header_max_size
4518 LOC: Config.maxReplyHeaderSize
4520 This specifies the maximum size for HTTP headers in a reply.
4521 Reply headers are usually relatively small (about 512 bytes).
4522 Placing a limit on the reply header size will catch certain
4523 bugs (for example with persistent connections) and possibly
4524 buffer-overflow or denial-of-service attacks.
4527 NAME: request_body_max_size
4531 LOC: Config.maxRequestBodySize
4533 This specifies the maximum size for an HTTP request body.
4534 In other words, the maximum size of a PUT/POST request.
4535 A user who attempts to send a request with a body larger
4536 than this limit receives an "Invalid Request" error message.
4537 If you set this parameter to a zero (the default), there will
4538 be no limit imposed.
4541 NAME: client_request_buffer_max_size
4545 LOC: Config.maxRequestBufferSize
4547 This specifies the maximum buffer size of a client request.
4548 It prevents squid eating too much memory when somebody uploads
4552 NAME: chunked_request_body_max_size
4556 LOC: Config.maxChunkedRequestBodySize
4558 A broken or confused HTTP/1.1 client may send a chunked HTTP
4559 request to Squid. Squid does not have full support for that
4560 feature yet. To cope with such requests, Squid buffers the
4561 entire request and then dechunks request body to create a
4562 plain HTTP/1.0 request with a known content length. The plain
4563 request is then used by the rest of Squid code as usual.
4565 The option value specifies the maximum size of the buffer used
4566 to hold the request before the conversion. If the chunked
4567 request size exceeds the specified limit, the conversion
4568 fails, and the client receives an "unsupported request" error,
4569 as if dechunking was disabled.
4571 Dechunking is enabled by default. To disable conversion of
4572 chunked requests, set the maximum to zero.
4574 Request dechunking feature and this option in particular are a
4575 temporary hack. When chunking requests and responses are fully
4576 supported, there will be no need to buffer a chunked request.
4580 IFDEF: USE_HTTP_VIOLATIONS
4583 LOC: Config.accessList.brokenPosts
4585 A list of ACL elements which, if matched, causes Squid to send
4586 an extra CRLF pair after the body of a PUT/POST request.
4588 Some HTTP servers has broken implementations of PUT/POST,
4589 and rely on an extra CRLF pair sent by some WWW clients.
4591 Quote from RFC2616 section 4.1 on this matter:
4593 Note: certain buggy HTTP/1.0 client implementations generate an
4594 extra CRLF's after a POST request. To restate what is explicitly
4595 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
4596 a request with an extra CRLF.
4598 This clause only supports fast acl types.
4599 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4602 acl buggy_server url_regex ^http://....
4603 broken_posts allow buggy_server
4606 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
4609 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
4611 LOC: Adaptation::Config::use_indirect_client
4613 Controls whether the indirect client IP address (instead of the direct
4614 client IP address) is passed to adaptation services.
4616 See also: follow_x_forwarded_for adaptation_send_client_ip
4620 IFDEF: USE_HTTP_VIOLATIONS
4624 LOC: Config.onoff.via
4626 If set (default), Squid will include a Via header in requests and
4627 replies as required by RFC2616.
4633 LOC: Config.onoff.ie_refresh
4636 Microsoft Internet Explorer up until version 5.5 Service
4637 Pack 1 has an issue with transparent proxies, wherein it
4638 is impossible to force a refresh. Turning this on provides
4639 a partial fix to the problem, by causing all IMS-REFRESH
4640 requests from older IE versions to check the origin server
4641 for fresh content. This reduces hit ratio by some amount
4642 (~10% in my experience), but allows users to actually get
4643 fresh content when they want it. Note because Squid
4644 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
4645 of 5.5 is unchanged from old versions of Squid (i.e. a
4646 forced refresh is impossible). Newer versions of IE will,
4647 hopefully, continue to have the new behavior and will be
4648 handled based on that assumption. This option defaults to
4649 the old Squid behavior, which is better for hit ratios but
4650 worse for clients using IE, if they need to be able to
4651 force fresh content.
4654 NAME: vary_ignore_expire
4657 LOC: Config.onoff.vary_ignore_expire
4660 Many HTTP servers supporting Vary gives such objects
4661 immediate expiry time with no cache-control header
4662 when requested by a HTTP/1.0 client. This option
4663 enables Squid to ignore such expiry times until
4664 HTTP/1.1 is fully implemented.
4666 WARNING: If turned on this may eventually cause some
4667 varying objects not intended for caching to get cached.
4670 NAME: request_entities
4672 LOC: Config.onoff.request_entities
4675 Squid defaults to deny GET and HEAD requests with request entities,
4676 as the meaning of such requests are undefined in the HTTP standard
4677 even if not explicitly forbidden.
4679 Set this directive to on if you have clients which insists
4680 on sending request entities in GET or HEAD requests. But be warned
4681 that there is server software (both proxies and web servers) which
4682 can fail to properly process this kind of request which may make you
4683 vulnerable to cache pollution attacks if enabled.
4686 NAME: request_header_access
4687 IFDEF: USE_HTTP_VIOLATIONS
4688 TYPE: http_header_access
4689 LOC: Config.request_header_access
4692 Usage: request_header_access header_name allow|deny [!]aclname ...
4694 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4695 this feature could make you liable for problems which it
4698 This option replaces the old 'anonymize_headers' and the
4699 older 'http_anonymizer' option with something that is much
4700 more configurable. A list of ACLs for each header name allows
4701 removal of specific header fields under specific conditions.
4703 This option only applies to outgoing HTTP request headers (i.e.,
4704 headers sent by Squid to the next HTTP hop such as a cache peer
4705 or an origin server). The option has no effect during cache hit
4706 detection. The equivalent adaptation vectoring point in ICAP
4707 terminology is post-cache REQMOD.
4709 The option is applied to individual outgoing request header
4710 fields. For each request header field F, Squid uses the first
4711 qualifying sets of request_header_access rules:
4713 1. Rules with header_name equal to F's name.
4714 2. Rules with header_name 'Other', provided F's name is not
4715 on the hard-coded list of commonly used HTTP header names.
4716 3. Rules with header_name 'All'.
4718 Within that qualifying rule set, rule ACLs are checked as usual.
4719 If ACLs of an "allow" rule match, the header field is allowed to
4720 go through as is. If ACLs of a "deny" rule match, the header is
4721 removed and request_header_replace is then checked to identify
4722 if the removed header has a replacement. If no rules within the
4723 set have matching ACLs, the header field is left as is.
4725 For example, to achieve the same behavior as the old
4726 'http_anonymizer standard' option, you should use:
4728 request_header_access From deny all
4729 request_header_access Referer deny all
4730 request_header_access Server deny all
4731 request_header_access User-Agent deny all
4732 request_header_access WWW-Authenticate deny all
4733 request_header_access Link deny all
4735 Or, to reproduce the old 'http_anonymizer paranoid' feature
4738 request_header_access Allow allow all
4739 request_header_access Authorization allow all
4740 request_header_access WWW-Authenticate allow all
4741 request_header_access Proxy-Authorization allow all
4742 request_header_access Proxy-Authenticate allow all
4743 request_header_access Cache-Control allow all
4744 request_header_access Content-Encoding allow all
4745 request_header_access Content-Length allow all
4746 request_header_access Content-Type allow all
4747 request_header_access Date allow all
4748 request_header_access Expires allow all
4749 request_header_access Host allow all
4750 request_header_access If-Modified-Since allow all
4751 request_header_access Last-Modified allow all
4752 request_header_access Location allow all
4753 request_header_access Pragma allow all
4754 request_header_access Accept allow all
4755 request_header_access Accept-Charset allow all
4756 request_header_access Accept-Encoding allow all
4757 request_header_access Accept-Language allow all
4758 request_header_access Content-Language allow all
4759 request_header_access Mime-Version allow all
4760 request_header_access Retry-After allow all
4761 request_header_access Title allow all
4762 request_header_access Connection allow all
4763 request_header_access All deny all
4765 although many of those are HTTP reply headers, and so should be
4766 controlled with the reply_header_access directive.
4768 By default, all headers are allowed (no anonymizing is
4772 NAME: reply_header_access
4773 IFDEF: USE_HTTP_VIOLATIONS
4774 TYPE: http_header_access
4775 LOC: Config.reply_header_access
4778 Usage: reply_header_access header_name allow|deny [!]aclname ...
4780 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4781 this feature could make you liable for problems which it
4784 This option only applies to reply headers, i.e., from the
4785 server to the client.
4787 This is the same as request_header_access, but in the other
4788 direction. Please see request_header_access for detailed
4791 For example, to achieve the same behavior as the old
4792 'http_anonymizer standard' option, you should use:
4794 reply_header_access From deny all
4795 reply_header_access Referer deny all
4796 reply_header_access Server deny all
4797 reply_header_access User-Agent deny all
4798 reply_header_access WWW-Authenticate deny all
4799 reply_header_access Link deny all
4801 Or, to reproduce the old 'http_anonymizer paranoid' feature
4804 reply_header_access Allow allow all
4805 reply_header_access Authorization allow all
4806 reply_header_access WWW-Authenticate allow all
4807 reply_header_access Proxy-Authorization allow all
4808 reply_header_access Proxy-Authenticate allow all
4809 reply_header_access Cache-Control allow all
4810 reply_header_access Content-Encoding allow all
4811 reply_header_access Content-Length allow all
4812 reply_header_access Content-Type allow all
4813 reply_header_access Date allow all
4814 reply_header_access Expires allow all
4815 reply_header_access Host allow all
4816 reply_header_access If-Modified-Since allow all
4817 reply_header_access Last-Modified allow all
4818 reply_header_access Location allow all
4819 reply_header_access Pragma allow all
4820 reply_header_access Accept allow all
4821 reply_header_access Accept-Charset allow all
4822 reply_header_access Accept-Encoding allow all
4823 reply_header_access Accept-Language allow all
4824 reply_header_access Content-Language allow all
4825 reply_header_access Mime-Version allow all
4826 reply_header_access Retry-After allow all
4827 reply_header_access Title allow all
4828 reply_header_access Connection allow all
4829 reply_header_access All deny all
4831 although the HTTP request headers won't be usefully controlled
4832 by this directive -- see request_header_access for details.
4834 By default, all headers are allowed (no anonymizing is
4838 NAME: request_header_replace header_replace
4839 IFDEF: USE_HTTP_VIOLATIONS
4840 TYPE: http_header_replace
4841 LOC: Config.request_header_access
4844 Usage: request_header_replace header_name message
4845 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
4847 This option allows you to change the contents of headers
4848 denied with request_header_access above, by replacing them
4849 with some fixed string. This replaces the old fake_user_agent
4852 This only applies to request headers, not reply headers.
4854 By default, headers are removed if denied.
4857 NAME: reply_header_replace
4858 IFDEF: USE_HTTP_VIOLATIONS
4859 TYPE: http_header_replace
4860 LOC: Config.reply_header_access
4863 Usage: reply_header_replace header_name message
4864 Example: reply_header_replace Server Foo/1.0
4866 This option allows you to change the contents of headers
4867 denied with reply_header_access above, by replacing them
4868 with some fixed string.
4870 This only applies to reply headers, not request headers.
4872 By default, headers are removed if denied.
4875 NAME: request_header_add
4876 TYPE: HeaderWithAclList
4877 LOC: Config.request_header_add
4880 Usage: request_header_add field-name field-value acl1 [acl2] ...
4881 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
4883 This option adds header fields to outgoing HTTP requests (i.e.,
4884 request headers sent by Squid to the next HTTP hop such as a
4885 cache peer or an origin server). The option has no effect during
4886 cache hit detection. The equivalent adaptation vectoring point
4887 in ICAP terminology is post-cache REQMOD.
4889 Field-name is a token specifying an HTTP header name. If a
4890 standard HTTP header name is used, Squid does not check whether
4891 the new header conflicts with any existing headers or violates
4892 HTTP rules. If the request to be modified already contains a
4893 field with the same name, the old field is preserved but the
4894 header field values are not merged.
4896 Field-value is either a token or a quoted string. If quoted
4897 string format is used, then the surrounding quotes are removed
4898 while escape sequences and %macros are processed.
4900 In theory, all of the logformat codes can be used as %macros.
4901 However, unlike logging (which happens at the very end of
4902 transaction lifetime), the transaction may not yet have enough
4903 information to expand a macro when the new header value is needed.
4904 And some information may already be available to Squid but not yet
4905 committed where the macro expansion code can access it (report
4906 such instances!). The macro will be expanded into a single dash
4907 ('-') in such cases. Not all macros have been tested.
4909 One or more Squid ACLs may be specified to restrict header
4910 injection to matching requests. As always in squid.conf, all
4911 ACLs in an option ACL list must be satisfied for the insertion
4912 to happen. The request_header_add option supports fast ACLs
4916 NAME: relaxed_header_parser
4917 COMMENT: on|off|warn
4919 LOC: Config.onoff.relaxed_header_parser
4922 In the default "on" setting Squid accepts certain forms
4923 of non-compliant HTTP messages where it is unambiguous
4924 what the sending application intended even if the message
4925 is not correctly formatted. The messages is then normalized
4926 to the correct form when forwarded by Squid.
4928 If set to "warn" then a warning will be emitted in cache.log
4929 each time such HTTP error is encountered.
4931 If set to "off" then such HTTP errors will cause the request
4932 or response to be rejected.
4937 -----------------------------------------------------------------------------
4940 NAME: forward_timeout
4943 LOC: Config.Timeout.forward
4946 This parameter specifies how long Squid should at most attempt in
4947 finding a forwarding path for the request before giving up.
4950 NAME: connect_timeout
4953 LOC: Config.Timeout.connect
4956 This parameter specifies how long to wait for the TCP connect to
4957 the requested server or peer to complete before Squid should
4958 attempt to find another path where to forward the request.
4961 NAME: peer_connect_timeout
4964 LOC: Config.Timeout.peer_connect
4967 This parameter specifies how long to wait for a pending TCP
4968 connection to a peer cache. The default is 30 seconds. You
4969 may also set different timeout values for individual neighbors
4970 with the 'connect-timeout' option on a 'cache_peer' line.
4976 LOC: Config.Timeout.read
4979 The read_timeout is applied on server-side connections. After
4980 each successful read(), the timeout will be extended by this
4981 amount. If no data is read again after this amount of time,
4982 the request is aborted and logged with ERR_READ_TIMEOUT. The
4983 default is 15 minutes.
4989 LOC: Config.Timeout.write
4992 This timeout is tracked for all connections that have data
4993 available for writing and are waiting for the socket to become
4994 ready. After each successful write, the timeout is extended by
4995 the configured amount. If Squid has data to write but the
4996 connection is not ready for the configured duration, the
4997 transaction associated with the connection is terminated. The
4998 default is 15 minutes.
5001 NAME: request_timeout
5003 LOC: Config.Timeout.request
5006 How long to wait for complete HTTP request headers after initial
5007 connection establishment.
5010 NAME: client_idle_pconn_timeout persistent_request_timeout
5012 LOC: Config.Timeout.clientIdlePconn
5015 How long to wait for the next HTTP request on a persistent
5016 client connection after the previous request completes.
5019 NAME: client_lifetime
5022 LOC: Config.Timeout.lifetime
5025 The maximum amount of time a client (browser) is allowed to
5026 remain connected to the cache process. This protects the Cache
5027 from having a lot of sockets (and hence file descriptors) tied up
5028 in a CLOSE_WAIT state from remote clients that go away without
5029 properly shutting down (either because of a network failure or
5030 because of a poor client implementation). The default is one
5033 NOTE: The default value is intended to be much larger than any
5034 client would ever need to be connected to your cache. You
5035 should probably change client_lifetime only as a last resort.
5036 If you seem to have many client connections tying up
5037 filedescriptors, we recommend first tuning the read_timeout,
5038 request_timeout, persistent_request_timeout and quick_abort values.
5041 NAME: half_closed_clients
5043 LOC: Config.onoff.half_closed_clients
5046 Some clients may shutdown the sending side of their TCP
5047 connections, while leaving their receiving sides open. Sometimes,
5048 Squid can not tell the difference between a half-closed and a
5049 fully-closed TCP connection.
5051 By default, Squid will immediately close client connections when
5052 read(2) returns "no more data to read."
5054 Change this option to 'on' and Squid will keep open connections
5055 until a read(2) or write(2) on the socket returns an error.
5056 This may show some benefits for reverse proxies. But if not
5057 it is recommended to leave OFF.
5060 NAME: server_idle_pconn_timeout pconn_timeout
5062 LOC: Config.Timeout.serverIdlePconn
5065 Timeout for idle persistent connections to servers and other
5072 LOC: Ident::TheConfig.timeout
5075 Maximum time to wait for IDENT lookups to complete.
5077 If this is too high, and you enabled IDENT lookups from untrusted
5078 users, you might be susceptible to denial-of-service by having
5079 many ident requests going at once.
5082 NAME: shutdown_lifetime
5085 LOC: Config.shutdownLifetime
5088 When SIGTERM or SIGHUP is received, the cache is put into
5089 "shutdown pending" mode until all active sockets are closed.
5090 This value is the lifetime to set for all open descriptors
5091 during shutdown mode. Any active clients after this many
5092 seconds will receive a 'timeout' message.
5096 ADMINISTRATIVE PARAMETERS
5097 -----------------------------------------------------------------------------
5103 LOC: Config.adminEmail
5105 Email-address of local cache manager who will receive
5106 mail if the cache dies. The default is "webmaster."
5112 LOC: Config.EmailFrom
5114 From: email-address for mail sent when the cache dies.
5115 The default is to use 'appname@unique_hostname'.
5116 Default appname value is "squid", can be changed into
5117 src/globals.h before building squid.
5123 LOC: Config.EmailProgram
5125 Email program used to send mail if the cache dies.
5126 The default is "mail". The specified program must comply
5127 with the standard Unix mail syntax:
5128 mail-program recipient < mailfile
5130 Optional command line options can be specified.
5133 NAME: cache_effective_user
5135 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
5136 LOC: Config.effectiveUser
5138 If you start Squid as root, it will change its effective/real
5139 UID/GID to the user specified below. The default is to change
5140 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
5141 see also; cache_effective_group
5144 NAME: cache_effective_group
5147 LOC: Config.effectiveGroup
5149 Squid sets the GID to the effective user's default group ID
5150 (taken from the password file) and supplementary group list
5151 from the groups membership.
5153 If you want Squid to run with a specific GID regardless of
5154 the group memberships of the effective user then set this
5155 to the group (or GID) you want Squid to run as. When set
5156 all other group privileges of the effective user are ignored
5157 and only this GID is effective. If Squid is not started as
5158 root the user starting Squid MUST be member of the specified
5161 This option is not recommended by the Squid Team.
5162 Our preference is for administrators to configure a secure
5163 user account for squid with UID/GID matching system policies.
5166 NAME: httpd_suppress_version_string
5170 LOC: Config.onoff.httpd_suppress_version_string
5172 Suppress Squid version string info in HTTP headers and HTML error pages.
5175 NAME: visible_hostname
5177 LOC: Config.visibleHostname
5180 If you want to present a special hostname in error messages, etc,
5181 define this. Otherwise, the return value of gethostname()
5182 will be used. If you have multiple caches in a cluster and
5183 get errors about IP-forwarding you must set them to have individual
5184 names with this setting.
5187 NAME: unique_hostname
5189 LOC: Config.uniqueHostname
5192 If you want to have multiple machines with the same
5193 'visible_hostname' you must give each machine a different
5194 'unique_hostname' so forwarding loops can be detected.
5197 NAME: hostname_aliases
5199 LOC: Config.hostnameAliases
5202 A list of other DNS names your cache has.
5210 Minimum umask which should be enforced while the proxy
5211 is running, in addition to the umask set at startup.
5213 For a traditional octal representation of umasks, start
5218 OPTIONS FOR THE CACHE REGISTRATION SERVICE
5219 -----------------------------------------------------------------------------
5221 This section contains parameters for the (optional) cache
5222 announcement service. This service is provided to help
5223 cache administrators locate one another in order to join or
5224 create cache hierarchies.
5226 An 'announcement' message is sent (via UDP) to the registration
5227 service by Squid. By default, the announcement message is NOT
5228 SENT unless you enable it with 'announce_period' below.
5230 The announcement message includes your hostname, plus the
5231 following information from this configuration file:
5237 All current information is processed regularly and made
5238 available on the Web at http://www.ircache.net/Cache/Tracker/.
5241 NAME: announce_period
5243 LOC: Config.Announce.period
5246 This is how frequently to send cache announcements. The
5247 default is `0' which disables sending the announcement
5250 To enable announcing your cache, just set an announce period.
5253 announce_period 1 day
5258 DEFAULT: tracker.ircache.net
5259 LOC: Config.Announce.host
5265 LOC: Config.Announce.file
5271 LOC: Config.Announce.port
5273 announce_host and announce_port set the hostname and port
5274 number where the registration message will be sent.
5276 Hostname will default to 'tracker.ircache.net' and port will
5277 default default to 3131. If the 'filename' argument is given,
5278 the contents of that file will be included in the announce
5283 HTTPD-ACCELERATOR OPTIONS
5284 -----------------------------------------------------------------------------
5287 NAME: httpd_accel_surrogate_id
5290 LOC: Config.Accel.surrogate_id
5292 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
5293 need an identification token to allow control targeting. Because
5294 a farm of surrogates may all perform the same tasks, they may share
5295 an identification token.
5297 The default ID is the visible_hostname
5300 NAME: http_accel_surrogate_remote
5304 LOC: Config.onoff.surrogate_is_remote
5306 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
5307 Set this to on to have squid behave as a remote surrogate.
5311 IFDEF: USE_SQUID_ESI
5312 COMMENT: libxml2|expat|custom
5314 LOC: ESIParser::Type
5317 ESI markup is not strictly XML compatible. The custom ESI parser
5318 will give higher performance, but cannot handle non ASCII character
5323 DELAY POOL PARAMETERS
5324 -----------------------------------------------------------------------------
5328 TYPE: delay_pool_count
5330 IFDEF: USE_DELAY_POOLS
5333 This represents the number of delay pools to be used. For example,
5334 if you have one class 2 delay pool and one class 3 delays pool, you
5335 have a total of 2 delay pools.
5339 TYPE: delay_pool_class
5341 IFDEF: USE_DELAY_POOLS
5344 This defines the class of each delay pool. There must be exactly one
5345 delay_class line for each delay pool. For example, to define two
5346 delay pools, one of class 2 and one of class 3, the settings above
5350 delay_pools 4 # 4 delay pools
5351 delay_class 1 2 # pool 1 is a class 2 pool
5352 delay_class 2 3 # pool 2 is a class 3 pool
5353 delay_class 3 4 # pool 3 is a class 4 pool
5354 delay_class 4 5 # pool 4 is a class 5 pool
5356 The delay pool classes are:
5358 class 1 Everything is limited by a single aggregate
5361 class 2 Everything is limited by a single aggregate
5362 bucket as well as an "individual" bucket chosen
5363 from bits 25 through 32 of the IPv4 address.
5365 class 3 Everything is limited by a single aggregate
5366 bucket as well as a "network" bucket chosen
5367 from bits 17 through 24 of the IP address and a
5368 "individual" bucket chosen from bits 17 through
5369 32 of the IPv4 address.
5371 class 4 Everything in a class 3 delay pool, with an
5372 additional limit on a per user basis. This
5373 only takes effect if the username is established
5374 in advance - by forcing authentication in your
5377 class 5 Requests are grouped according their tag (see
5378 external_acl's tag= reply).
5381 Each pool also requires a delay_parameters directive to configure the pool size
5382 and speed limits used whenever the pool is applied to a request. Along with
5383 a set of delay_access directives to determine when it is used.
5385 NOTE: If an IP address is a.b.c.d
5386 -> bits 25 through 32 are "d"
5387 -> bits 17 through 24 are "c"
5388 -> bits 17 through 32 are "c * 256 + d"
5390 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
5391 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
5395 TYPE: delay_pool_access
5397 IFDEF: USE_DELAY_POOLS
5400 This is used to determine which delay pool a request falls into.
5402 delay_access is sorted per pool and the matching starts with pool 1,
5403 then pool 2, ..., and finally pool N. The first delay pool where the
5404 request is allowed is selected for the request. If it does not allow
5405 the request to any pool then the request is not delayed (default).
5407 For example, if you want some_big_clients in delay
5408 pool 1 and lotsa_little_clients in delay pool 2:
5411 delay_access 1 allow some_big_clients
5412 delay_access 1 deny all
5413 delay_access 2 allow lotsa_little_clients
5414 delay_access 2 deny all
5415 delay_access 3 allow authenticated_clients
5418 NAME: delay_parameters
5419 TYPE: delay_pool_rates
5421 IFDEF: USE_DELAY_POOLS
5424 This defines the parameters for a delay pool. Each delay pool has
5425 a number of "buckets" associated with it, as explained in the
5426 description of delay_class.
5428 For a class 1 delay pool, the syntax is:
5430 delay_parameters pool aggregate
5432 For a class 2 delay pool:
5434 delay_parameters pool aggregate individual
5436 For a class 3 delay pool:
5438 delay_parameters pool aggregate network individual
5440 For a class 4 delay pool:
5442 delay_parameters pool aggregate network individual user
5444 For a class 5 delay pool:
5446 delay_parameters pool tagrate
5448 The option variables are:
5450 pool a pool number - ie, a number between 1 and the
5451 number specified in delay_pools as used in
5454 aggregate the speed limit parameters for the aggregate bucket
5457 individual the speed limit parameters for the individual
5458 buckets (class 2, 3).
5460 network the speed limit parameters for the network buckets
5463 user the speed limit parameters for the user buckets
5466 tagrate the speed limit parameters for the tag buckets
5469 A pair of delay parameters is written restore/maximum, where restore is
5470 the number of bytes (not bits - modem and network speeds are usually
5471 quoted in bits) per second placed into the bucket, and maximum is the
5472 maximum number of bytes which can be in the bucket at any time.
5474 There must be one delay_parameters line for each delay pool.
5477 For example, if delay pool number 1 is a class 2 delay pool as in the
5478 above example, and is being used to strictly limit each host to 64Kbit/sec
5479 (plus overheads), with no overall limit, the line is:
5481 delay_parameters 1 -1/-1 8000/8000
5483 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
5485 Note that the figure -1 is used to represent "unlimited".
5488 And, if delay pool number 2 is a class 3 delay pool as in the above
5489 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
5490 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
5491 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
5492 to permit a decent web page to be downloaded at a decent speed
5493 (if the network is not being limited due to overuse) but slow down
5494 large downloads more significantly:
5496 delay_parameters 2 32000/32000 8000/8000 600/8000
5498 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
5499 8 x 8000 KByte/sec -> 64Kbit/sec.
5500 8 x 600 Byte/sec -> 4800bit/sec.
5503 Finally, for a class 4 delay pool as in the example - each user will
5504 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
5506 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
5509 NAME: delay_initial_bucket_level
5510 COMMENT: (percent, 0-100)
5513 IFDEF: USE_DELAY_POOLS
5514 LOC: Config.Delay.initial
5516 The initial bucket percentage is used to determine how much is put
5517 in each bucket when squid starts, is reconfigured, or first notices
5518 a host accessing it (in class 2 and class 3, individual hosts and
5519 networks only have buckets associated with them once they have been
5524 CLIENT DELAY POOL PARAMETERS
5525 -----------------------------------------------------------------------------
5528 NAME: client_delay_pools
5529 TYPE: client_delay_pool_count
5531 IFDEF: USE_DELAY_POOLS
5532 LOC: Config.ClientDelay
5534 This option specifies the number of client delay pools used. It must
5535 preceed other client_delay_* options.
5538 client_delay_pools 2
5541 NAME: client_delay_initial_bucket_level
5542 COMMENT: (percent, 0-no_limit)
5545 IFDEF: USE_DELAY_POOLS
5546 LOC: Config.ClientDelay.initial
5548 This option determines the initial bucket size as a percentage of
5549 max_bucket_size from client_delay_parameters. Buckets are created
5550 at the time of the "first" connection from the matching IP. Idle
5551 buckets are periodically deleted up.
5553 You can specify more than 100 percent but note that such "oversized"
5554 buckets are not refilled until their size goes down to max_bucket_size
5555 from client_delay_parameters.
5558 client_delay_initial_bucket_level 50
5561 NAME: client_delay_parameters
5562 TYPE: client_delay_pool_rates
5564 IFDEF: USE_DELAY_POOLS
5565 LOC: Config.ClientDelay
5568 This option configures client-side bandwidth limits using the
5571 client_delay_parameters pool speed_limit max_bucket_size
5573 pool is an integer ID used for client_delay_access matching.
5575 speed_limit is bytes added to the bucket per second.
5577 max_bucket_size is the maximum size of a bucket, enforced after any
5578 speed_limit additions.
5580 Please see the delay_parameters option for more information and
5584 client_delay_parameters 1 1024 2048
5585 client_delay_parameters 2 51200 16384
5588 NAME: client_delay_access
5589 TYPE: client_delay_pool_access
5591 IFDEF: USE_DELAY_POOLS
5592 LOC: Config.ClientDelay
5595 This option determines the client-side delay pool for the
5598 client_delay_access pool_ID allow|deny acl_name
5600 All client_delay_access options are checked in their pool ID
5601 order, starting with pool 1. The first checked pool with allowed
5602 request is selected for the request. If no ACL matches or there
5603 are no client_delay_access options, the request bandwidth is not
5606 The ACL-selected pool is then used to find the
5607 client_delay_parameters for the request. Client-side pools are
5608 not used to aggregate clients. Clients are always aggregated
5609 based on their source IP addresses (one bucket per source IP).
5611 Please see delay_access for more examples.
5614 client_delay_access 1 allow low_rate_network
5615 client_delay_access 2 allow vips_network
5619 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
5620 -----------------------------------------------------------------------------
5625 LOC: Config.Wccp.router
5629 Use this option to define your WCCP ``home'' router for
5632 wccp_router supports a single WCCP(v1) router
5634 wccp2_router supports multiple WCCPv2 routers
5636 only one of the two may be used at the same time and defines
5637 which version of WCCP to use.
5641 TYPE: IpAddress_list
5642 LOC: Config.Wccp2.router
5646 Use this option to define your WCCP ``home'' router for
5649 wccp_router supports a single WCCP(v1) router
5651 wccp2_router supports multiple WCCPv2 routers
5653 only one of the two may be used at the same time and defines
5654 which version of WCCP to use.
5659 LOC: Config.Wccp.version
5663 This directive is only relevant if you need to set up WCCP(v1)
5664 to some very old and end-of-life Cisco routers. In all other
5665 setups it must be left unset or at the default setting.
5666 It defines an internal version in the WCCP(v1) protocol,
5667 with version 4 being the officially documented protocol.
5669 According to some users, Cisco IOS 11.2 and earlier only
5670 support WCCP version 3. If you're using that or an earlier
5671 version of IOS, you may need to change this value to 3, otherwise
5672 do not specify this parameter.
5675 NAME: wccp2_rebuild_wait
5677 LOC: Config.Wccp2.rebuildwait
5681 If this is enabled Squid will wait for the cache dir rebuild to finish
5682 before sending the first wccp2 HereIAm packet
5685 NAME: wccp2_forwarding_method
5687 LOC: Config.Wccp2.forwarding_method
5691 WCCP2 allows the setting of forwarding methods between the
5692 router/switch and the cache. Valid values are as follows:
5694 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5695 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5697 Currently (as of IOS 12.4) cisco routers only support GRE.
5698 Cisco switches only support the L2 redirect assignment method.
5701 NAME: wccp2_return_method
5703 LOC: Config.Wccp2.return_method
5707 WCCP2 allows the setting of return methods between the
5708 router/switch and the cache for packets that the cache
5709 decides not to handle. Valid values are as follows:
5711 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5712 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5714 Currently (as of IOS 12.4) cisco routers only support GRE.
5715 Cisco switches only support the L2 redirect assignment.
5717 If the "ip wccp redirect exclude in" command has been
5718 enabled on the cache interface, then it is still safe for
5719 the proxy server to use a l2 redirect method even if this
5720 option is set to GRE.
5723 NAME: wccp2_assignment_method
5725 LOC: Config.Wccp2.assignment_method
5729 WCCP2 allows the setting of methods to assign the WCCP hash
5730 Valid values are as follows:
5732 hash - Hash assignment
5733 mask - Mask assignment
5735 As a general rule, cisco routers support the hash assignment method
5736 and cisco switches support the mask assignment method.
5741 LOC: Config.Wccp2.info
5742 DEFAULT_IF_NONE: standard 0
5745 WCCP2 allows for multiple traffic services. There are two
5746 types: "standard" and "dynamic". The standard type defines
5747 one service id - http (id 0). The dynamic service ids can be from
5748 51 to 255 inclusive. In order to use a dynamic service id
5749 one must define the type of traffic to be redirected; this is done
5750 using the wccp2_service_info option.
5752 The "standard" type does not require a wccp2_service_info option,
5753 just specifying the service id will suffice.
5755 MD5 service authentication can be enabled by adding
5756 "password=<password>" to the end of this service declaration.
5760 wccp2_service standard 0 # for the 'web-cache' standard service
5761 wccp2_service dynamic 80 # a dynamic service type which will be
5762 # fleshed out with subsequent options.
5763 wccp2_service standard 0 password=foo
5766 NAME: wccp2_service_info
5767 TYPE: wccp2_service_info
5768 LOC: Config.Wccp2.info
5772 Dynamic WCCPv2 services require further information to define the
5773 traffic you wish to have diverted.
5777 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
5778 priority=<priority> ports=<port>,<port>..
5780 The relevant WCCPv2 flags:
5781 + src_ip_hash, dst_ip_hash
5782 + source_port_hash, dst_port_hash
5783 + src_ip_alt_hash, dst_ip_alt_hash
5784 + src_port_alt_hash, dst_port_alt_hash
5787 The port list can be one to eight entries.
5791 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
5792 priority=240 ports=80
5794 Note: the service id must have been defined by a previous
5795 'wccp2_service dynamic <id>' entry.
5800 LOC: Config.Wccp2.weight
5804 Each cache server gets assigned a set of the destination
5805 hash proportional to their weight.
5810 LOC: Config.Wccp.address
5817 LOC: Config.Wccp2.address
5821 Use this option if you require WCCP to use a specific
5824 The default behavior is to not bind to any specific address.
5828 PERSISTENT CONNECTION HANDLING
5829 -----------------------------------------------------------------------------
5831 Also see "pconn_timeout" in the TIMEOUTS section
5834 NAME: client_persistent_connections
5836 LOC: Config.onoff.client_pconns
5840 NAME: server_persistent_connections
5842 LOC: Config.onoff.server_pconns
5845 Persistent connection support for clients and servers. By
5846 default, Squid uses persistent connections (when allowed)
5847 with its clients and servers. You can use these options to
5848 disable persistent connections with clients and/or servers.
5851 NAME: persistent_connection_after_error
5853 LOC: Config.onoff.error_pconns
5856 With this directive the use of persistent connections after
5857 HTTP errors can be disabled. Useful if you have clients
5858 who fail to handle errors on persistent connections proper.
5861 NAME: detect_broken_pconn
5863 LOC: Config.onoff.detect_broken_server_pconns
5866 Some servers have been found to incorrectly signal the use
5867 of HTTP/1.0 persistent connections even on replies not
5868 compatible, causing significant delays. This server problem
5869 has mostly been seen on redirects.
5871 By enabling this directive Squid attempts to detect such
5872 broken replies and automatically assume the reply is finished
5873 after 10 seconds timeout.
5877 CACHE DIGEST OPTIONS
5878 -----------------------------------------------------------------------------
5881 NAME: digest_generation
5882 IFDEF: USE_CACHE_DIGESTS
5884 LOC: Config.onoff.digest_generation
5887 This controls whether the server will generate a Cache Digest
5888 of its contents. By default, Cache Digest generation is
5889 enabled if Squid is compiled with --enable-cache-digests defined.
5892 NAME: digest_bits_per_entry
5893 IFDEF: USE_CACHE_DIGESTS
5895 LOC: Config.digest.bits_per_entry
5898 This is the number of bits of the server's Cache Digest which
5899 will be associated with the Digest entry for a given HTTP
5900 Method and URL (public key) combination. The default is 5.
5903 NAME: digest_rebuild_period
5904 IFDEF: USE_CACHE_DIGESTS
5907 LOC: Config.digest.rebuild_period
5910 This is the wait time between Cache Digest rebuilds.
5913 NAME: digest_rewrite_period
5915 IFDEF: USE_CACHE_DIGESTS
5917 LOC: Config.digest.rewrite_period
5920 This is the wait time between Cache Digest writes to
5924 NAME: digest_swapout_chunk_size
5927 IFDEF: USE_CACHE_DIGESTS
5928 LOC: Config.digest.swapout_chunk_size
5931 This is the number of bytes of the Cache Digest to write to
5932 disk at a time. It defaults to 4096 bytes (4KB), the Squid
5936 NAME: digest_rebuild_chunk_percentage
5937 COMMENT: (percent, 0-100)
5938 IFDEF: USE_CACHE_DIGESTS
5940 LOC: Config.digest.rebuild_chunk_percentage
5943 This is the percentage of the Cache Digest to be scanned at a
5944 time. By default it is set to 10% of the Cache Digest.
5949 -----------------------------------------------------------------------------
5954 LOC: Config.Port.snmp
5958 The port number where Squid listens for SNMP requests. To enable
5959 SNMP support set this to a suitable port number. Port number
5960 3401 is often used for the Squid SNMP agent. By default it's
5961 set to "0" (disabled)
5969 LOC: Config.accessList.snmp
5970 DEFAULT_IF_NONE: deny all
5973 Allowing or denying access to the SNMP port.
5975 All access to the agent is denied by default.
5978 snmp_access allow|deny [!]aclname ...
5980 This clause only supports fast acl types.
5981 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5983 snmp_access allow snmppublic localhost
5984 snmp_access deny all
5987 NAME: snmp_incoming_address
5989 LOC: Config.Addrs.snmp_incoming
5994 NAME: snmp_outgoing_address
5996 LOC: Config.Addrs.snmp_outgoing
6000 Just like 'udp_incoming_address', but for the SNMP port.
6002 snmp_incoming_address is used for the SNMP socket receiving
6003 messages from SNMP agents.
6004 snmp_outgoing_address is used for SNMP packets returned to SNMP
6007 The default snmp_incoming_address is to listen on all
6008 available network interfaces.
6010 If snmp_outgoing_address is not set it will use the same socket
6011 as snmp_incoming_address. Only change this if you want to have
6012 SNMP replies sent using another address than where this Squid
6013 listens for SNMP queries.
6015 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
6016 the same value since they both use port 3401.
6021 -----------------------------------------------------------------------------
6024 NAME: icp_port udp_port
6027 LOC: Config.Port.icp
6029 The port number where Squid sends and receives ICP queries to
6030 and from neighbor caches. The standard UDP port for ICP is 3130.
6031 Default is disabled (0).
6034 icp_port @DEFAULT_ICP_PORT@
6041 LOC: Config.Port.htcp
6043 The port number where Squid sends and receives HTCP queries to
6044 and from neighbor caches. To turn it on you want to set it to
6045 4827. By default it is set to "0" (disabled).
6051 NAME: log_icp_queries
6055 LOC: Config.onoff.log_udp
6057 If set, ICP queries are logged to access.log. You may wish
6058 do disable this if your ICP load is VERY high to speed things
6059 up or to simplify log analysis.
6062 NAME: udp_incoming_address
6064 LOC:Config.Addrs.udp_incoming
6067 udp_incoming_address is used for UDP packets received from other
6070 The default behavior is to not bind to any specific address.
6072 Only change this if you want to have all UDP queries received on
6073 a specific interface/address.
6075 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
6076 modules. Altering it will affect all of them in the same manner.
6078 see also; udp_outgoing_address
6080 NOTE, udp_incoming_address and udp_outgoing_address can not
6081 have the same value since they both use the same port.
6084 NAME: udp_outgoing_address
6086 LOC: Config.Addrs.udp_outgoing
6089 udp_outgoing_address is used for UDP packets sent out to other
6092 The default behavior is to not bind to any specific address.
6094 Instead it will use the same socket as udp_incoming_address.
6095 Only change this if you want to have UDP queries sent using another
6096 address than where this Squid listens for UDP queries from other
6099 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
6100 modules. Altering it will affect all of them in the same manner.
6102 see also; udp_incoming_address
6104 NOTE, udp_incoming_address and udp_outgoing_address can not
6105 have the same value since they both use the same port.
6112 LOC: Config.onoff.icp_hit_stale
6114 If you want to return ICP_HIT for stale cache objects, set this
6115 option to 'on'. If you have sibling relationships with caches
6116 in other administrative domains, this should be 'off'. If you only
6117 have sibling relationships with caches under your control,
6118 it is probably okay to set this to 'on'.
6119 If set to 'on', your siblings should use the option "allow-miss"
6120 on their cache_peer lines for connecting to you.
6123 NAME: minimum_direct_hops
6126 LOC: Config.minDirectHops
6128 If using the ICMP pinging stuff, do direct fetches for sites
6129 which are no more than this many hops away.
6132 NAME: minimum_direct_rtt
6135 LOC: Config.minDirectRtt
6137 If using the ICMP pinging stuff, do direct fetches for sites
6138 which are no more than this many rtt milliseconds away.
6144 LOC: Config.Netdb.low
6150 LOC: Config.Netdb.high
6152 The low and high water marks for the ICMP measurement
6153 database. These are counts, not percents. The defaults are
6154 900 and 1000. When the high water mark is reached, database
6155 entries will be deleted until the low mark is reached.
6158 NAME: netdb_ping_period
6160 LOC: Config.Netdb.period
6163 The minimum period for measuring a site. There will be at
6164 least this much delay between successive pings to the same
6165 network. The default is five minutes.
6172 LOC: Config.onoff.query_icmp
6174 If you want to ask your peers to include ICMP data in their ICP
6175 replies, enable this option.
6177 If your peer has configured Squid (during compilation) with
6178 '--enable-icmp' that peer will send ICMP pings to origin server
6179 sites of the URLs it receives. If you enable this option the
6180 ICP replies from that peer will include the ICMP data (if available).
6181 Then, when choosing a parent cache, Squid will choose the parent with
6182 the minimal RTT to the origin server. When this happens, the
6183 hierarchy field of the access.log will be
6184 "CLOSEST_PARENT_MISS". This option is off by default.
6187 NAME: test_reachability
6191 LOC: Config.onoff.test_reachability
6193 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
6194 instead of ICP_MISS if the target host is NOT in the ICMP
6195 database, or has a zero RTT.
6198 NAME: icp_query_timeout
6202 LOC: Config.Timeout.icp_query
6204 Normally Squid will automatically determine an optimal ICP
6205 query timeout value based on the round-trip-time of recent ICP
6206 queries. If you want to override the value determined by
6207 Squid, set this 'icp_query_timeout' to a non-zero value. This
6208 value is specified in MILLISECONDS, so, to use a 2-second
6209 timeout (the old default), you would write:
6211 icp_query_timeout 2000
6214 NAME: maximum_icp_query_timeout
6218 LOC: Config.Timeout.icp_query_max
6220 Normally the ICP query timeout is determined dynamically. But
6221 sometimes it can lead to very large values (say 5 seconds).
6222 Use this option to put an upper limit on the dynamic timeout
6223 value. Do NOT use this option to always use a fixed (instead
6224 of a dynamic) timeout value. To set a fixed timeout see the
6225 'icp_query_timeout' directive.
6228 NAME: minimum_icp_query_timeout
6232 LOC: Config.Timeout.icp_query_min
6234 Normally the ICP query timeout is determined dynamically. But
6235 sometimes it can lead to very small timeouts, even lower than
6236 the normal latency variance on your link due to traffic.
6237 Use this option to put an lower limit on the dynamic timeout
6238 value. Do NOT use this option to always use a fixed (instead
6239 of a dynamic) timeout value. To set a fixed timeout see the
6240 'icp_query_timeout' directive.
6243 NAME: background_ping_rate
6247 LOC: Config.backgroundPingRate
6249 Controls how often the ICP pings are sent to siblings that
6250 have background-ping set.
6254 MULTICAST ICP OPTIONS
6255 -----------------------------------------------------------------------------
6260 LOC: Config.mcast_group_list
6263 This tag specifies a list of multicast groups which your server
6264 should join to receive multicasted ICP queries.
6266 NOTE! Be very careful what you put here! Be sure you
6267 understand the difference between an ICP _query_ and an ICP
6268 _reply_. This option is to be set only if you want to RECEIVE
6269 multicast queries. Do NOT set this option to SEND multicast
6270 ICP (use cache_peer for that). ICP replies are always sent via
6271 unicast, so this option does not affect whether or not you will
6272 receive replies from multicast group members.
6274 You must be very careful to NOT use a multicast address which
6275 is already in use by another group of caches.
6277 If you are unsure about multicast, please read the Multicast
6278 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
6280 Usage: mcast_groups 239.128.16.128 224.0.1.20
6282 By default, Squid doesn't listen on any multicast groups.
6285 NAME: mcast_miss_addr
6286 IFDEF: MULTICAST_MISS_STREAM
6288 LOC: Config.mcast_miss.addr
6291 If you enable this option, every "cache miss" URL will
6292 be sent out on the specified multicast address.
6294 Do not enable this option unless you are are absolutely
6295 certain you understand what you are doing.
6298 NAME: mcast_miss_ttl
6299 IFDEF: MULTICAST_MISS_STREAM
6301 LOC: Config.mcast_miss.ttl
6304 This is the time-to-live value for packets multicasted
6305 when multicasting off cache miss URLs is enabled. By
6306 default this is set to 'site scope', i.e. 16.
6309 NAME: mcast_miss_port
6310 IFDEF: MULTICAST_MISS_STREAM
6312 LOC: Config.mcast_miss.port
6315 This is the port number to be used in conjunction with
6319 NAME: mcast_miss_encode_key
6320 IFDEF: MULTICAST_MISS_STREAM
6322 LOC: Config.mcast_miss.encode_key
6323 DEFAULT: XXXXXXXXXXXXXXXX
6325 The URLs that are sent in the multicast miss stream are
6326 encrypted. This is the encryption key.
6329 NAME: mcast_icp_query_timeout
6333 LOC: Config.Timeout.mcast_icp_query
6335 For multicast peers, Squid regularly sends out ICP "probes" to
6336 count how many other peers are listening on the given multicast
6337 address. This value specifies how long Squid should wait to
6338 count all the replies. The default is 2000 msec, or 2
6343 INTERNAL ICON OPTIONS
6344 -----------------------------------------------------------------------------
6347 NAME: icon_directory
6349 LOC: Config.icons.directory
6350 DEFAULT: @DEFAULT_ICON_DIR@
6352 Where the icons are stored. These are normally kept in
6356 NAME: global_internal_static
6358 LOC: Config.onoff.global_internal_static
6361 This directive controls is Squid should intercept all requests for
6362 /squid-internal-static/ no matter which host the URL is requesting
6363 (default on setting), or if nothing special should be done for
6364 such URLs (off setting). The purpose of this directive is to make
6365 icons etc work better in complex cache hierarchies where it may
6366 not always be possible for all corners in the cache mesh to reach
6367 the server generating a directory listing.
6370 NAME: short_icon_urls
6372 LOC: Config.icons.use_short_names
6375 If this is enabled Squid will use short URLs for icons.
6376 If disabled it will revert to the old behavior of including
6377 it's own name and port in the URL.
6379 If you run a complex cache hierarchy with a mix of Squid and
6380 other proxies you may need to disable this directive.
6385 -----------------------------------------------------------------------------
6388 NAME: error_directory
6390 LOC: Config.errorDirectory
6393 If you wish to create your own versions of the default
6394 error files to customize them to suit your company copy
6395 the error/template files to another directory and point
6398 WARNING: This option will disable multi-language support
6399 on error pages if used.
6401 The squid developers are interested in making squid available in
6402 a wide variety of languages. If you are making translations for a
6403 language that Squid does not currently provide please consider
6404 contributing your translation back to the project.
6405 http://wiki.squid-cache.org/Translations
6407 The squid developers working on translations are happy to supply drop-in
6408 translated error files in exchange for any new language contributions.
6411 NAME: error_default_language
6412 IFDEF: USE_ERR_LOCALES
6414 LOC: Config.errorDefaultLanguage
6417 Set the default language which squid will send error pages in
6418 if no existing translation matches the clients language
6421 If unset (default) generic English will be used.
6423 The squid developers are interested in making squid available in
6424 a wide variety of languages. If you are interested in making
6425 translations for any language see the squid wiki for details.
6426 http://wiki.squid-cache.org/Translations
6429 NAME: error_log_languages
6430 IFDEF: USE_ERR_LOCALES
6432 LOC: Config.errorLogMissingLanguages
6435 Log to cache.log what languages users are attempting to
6436 auto-negotiate for translations.
6438 Successful negotiations are not logged. Only failures
6439 have meaning to indicate that Squid may need an upgrade
6440 of its error page translations.
6443 NAME: err_page_stylesheet
6445 LOC: Config.errorStylesheet
6446 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
6448 CSS Stylesheet to pattern the display of Squid default error pages.
6450 For information on CSS see http://www.w3.org/Style/CSS/
6455 LOC: Config.errHtmlText
6458 HTML text to include in error messages. Make this a "mailto"
6459 URL to your admin address, or maybe just a link to your
6460 organizations Web page.
6462 To include this in your error messages, you must rewrite
6463 the error template files (found in the "errors" directory).
6464 Wherever you want the 'err_html_text' line to appear,
6465 insert a %L tag in the error template file.
6468 NAME: email_err_data
6471 LOC: Config.onoff.emailErrData
6474 If enabled, information about the occurred error will be
6475 included in the mailto links of the ERR pages (if %W is set)
6476 so that the email body contains the data.
6477 Syntax is <A HREF="mailto:%w%W">%w</A>
6482 LOC: Config.denyInfoList
6485 Usage: deny_info err_page_name acl
6486 or deny_info http://... acl
6487 or deny_info TCP_RESET acl
6489 This can be used to return a ERR_ page for requests which
6490 do not pass the 'http_access' rules. Squid remembers the last
6491 acl it evaluated in http_access, and if a 'deny_info' line exists
6492 for that ACL Squid returns a corresponding error page.
6494 The acl is typically the last acl on the http_access deny line which
6495 denied access. The exceptions to this rule are:
6496 - When Squid needs to request authentication credentials. It's then
6497 the first authentication related acl encountered
6498 - When none of the http_access lines matches. It's then the last
6499 acl processed on the last http_access line.
6500 - When the decision to deny access was made by an adaptation service,
6501 the acl name is the corresponding eCAP or ICAP service_name.
6503 NP: If providing your own custom error pages with error_directory
6504 you may also specify them by your custom file name:
6505 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
6507 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
6508 may be specified by prefixing the file name with the code and a colon.
6509 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
6511 Alternatively you can tell Squid to reset the TCP connection
6512 by specifying TCP_RESET.
6514 Or you can specify an error URL or URL pattern. The browsers will
6515 get redirected to the specified URL after formatting tags have
6516 been replaced. Redirect will be done with 302 or 307 according to
6517 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
6518 the URL. e.g. 303:http://example.com/
6521 %a - username (if available. Password NOT included)
6524 %E - Error description
6526 %H - Request domain name
6527 %i - Client IP Address
6529 %o - Message result from external ACL helper
6530 %p - Request Port number
6531 %P - Request Protocol name
6532 %R - Request URL path
6533 %T - Timestamp in RFC 1123 format
6534 %U - Full canonical URL from client
6535 (HTTPS URLs terminate with *)
6536 %u - Full canonical URL from client
6537 %w - Admin email from squid.conf
6539 %% - Literal percent (%) code
6544 OPTIONS INFLUENCING REQUEST FORWARDING
6545 -----------------------------------------------------------------------------
6548 NAME: nonhierarchical_direct
6550 LOC: Config.onoff.nonhierarchical_direct
6553 By default, Squid will send any non-hierarchical requests
6554 (matching hierarchy_stoplist or not cacheable request type) direct
6557 If you set this to off, Squid will prefer to send these
6558 requests to parents.
6560 Note that in most configurations, by turning this off you will only
6561 add latency to these request without any improvement in global hit
6564 If you are inside an firewall see never_direct instead of
6570 LOC: Config.onoff.prefer_direct
6573 Normally Squid tries to use parents for most requests. If you for some
6574 reason like it to first try going direct and only use a parent if
6575 going direct fails set this to on.
6577 By combining nonhierarchical_direct off and prefer_direct on you
6578 can set up Squid to use a parent as a backup path if going direct
6581 Note: If you want Squid to use parents for all requests see
6582 the never_direct directive. prefer_direct only modifies how Squid
6583 acts on cacheable requests.
6588 LOC: Config.accessList.AlwaysDirect
6591 Usage: always_direct allow|deny [!]aclname ...
6593 Here you can use ACL elements to specify requests which should
6594 ALWAYS be forwarded by Squid to the origin servers without using
6595 any peers. For example, to always directly forward requests for
6596 local servers ignoring any parents or siblings you may have use
6599 acl local-servers dstdomain my.domain.net
6600 always_direct allow local-servers
6602 To always forward FTP requests directly, use
6605 always_direct allow FTP
6607 NOTE: There is a similar, but opposite option named
6608 'never_direct'. You need to be aware that "always_direct deny
6609 foo" is NOT the same thing as "never_direct allow foo". You
6610 may need to use a deny rule to exclude a more-specific case of
6611 some other rule. Example:
6613 acl local-external dstdomain external.foo.net
6614 acl local-servers dstdomain .foo.net
6615 always_direct deny local-external
6616 always_direct allow local-servers
6618 NOTE: If your goal is to make the client forward the request
6619 directly to the origin server bypassing Squid then this needs
6620 to be done in the client configuration. Squid configuration
6621 can only tell Squid how Squid should fetch the object.
6623 NOTE: This directive is not related to caching. The replies
6624 is cached as usual even if you use always_direct. To not cache
6625 the replies see the 'cache' directive.
6627 This clause supports both fast and slow acl types.
6628 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6633 LOC: Config.accessList.NeverDirect
6636 Usage: never_direct allow|deny [!]aclname ...
6638 never_direct is the opposite of always_direct. Please read
6639 the description for always_direct if you have not already.
6641 With 'never_direct' you can use ACL elements to specify
6642 requests which should NEVER be forwarded directly to origin
6643 servers. For example, to force the use of a proxy for all
6644 requests, except those in your local domain use something like:
6646 acl local-servers dstdomain .foo.net
6647 never_direct deny local-servers
6648 never_direct allow all
6650 or if Squid is inside a firewall and there are local intranet
6651 servers inside the firewall use something like:
6653 acl local-intranet dstdomain .foo.net
6654 acl local-external dstdomain external.foo.net
6655 always_direct deny local-external
6656 always_direct allow local-intranet
6657 never_direct allow all
6659 This clause supports both fast and slow acl types.
6660 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6664 ADVANCED NETWORKING OPTIONS
6665 -----------------------------------------------------------------------------
6668 NAME: incoming_udp_average incoming_icp_average
6671 LOC: Config.comm_incoming.udp.average
6673 Heavy voodoo here. I can't even believe you are reading this.
6674 Are you crazy? Don't even think about adjusting these unless
6675 you understand the algorithms in comm_select.c first!
6678 NAME: incoming_tcp_average incoming_http_average
6681 LOC: Config.comm_incoming.tcp.average
6683 Heavy voodoo here. I can't even believe you are reading this.
6684 Are you crazy? Don't even think about adjusting these unless
6685 you understand the algorithms in comm_select.c first!
6688 NAME: incoming_dns_average
6691 LOC: Config.comm_incoming.dns.average
6693 Heavy voodoo here. I can't even believe you are reading this.
6694 Are you crazy? Don't even think about adjusting these unless
6695 you understand the algorithms in comm_select.c first!
6698 NAME: min_udp_poll_cnt min_icp_poll_cnt
6701 LOC: Config.comm_incoming.udp.min_poll
6703 Heavy voodoo here. I can't even believe you are reading this.
6704 Are you crazy? Don't even think about adjusting these unless
6705 you understand the algorithms in comm_select.c first!
6708 NAME: min_dns_poll_cnt
6711 LOC: Config.comm_incoming.dns.min_poll
6713 Heavy voodoo here. I can't even believe you are reading this.
6714 Are you crazy? Don't even think about adjusting these unless
6715 you understand the algorithms in comm_select.c first!
6718 NAME: min_tcp_poll_cnt min_http_poll_cnt
6721 LOC: Config.comm_incoming.tcp.min_poll
6723 Heavy voodoo here. I can't even believe you are reading this.
6724 Are you crazy? Don't even think about adjusting these unless
6725 you understand the algorithms in comm_select.c first!
6731 LOC: Config.accept_filter
6735 The name of an accept(2) filter to install on Squid's
6736 listen socket(s). This feature is perhaps specific to
6737 FreeBSD and requires support in the kernel.
6739 The 'httpready' filter delays delivering new connections
6740 to Squid until a full HTTP request has been received.
6741 See the accf_http(9) man page for details.
6743 The 'dataready' filter delays delivering new connections
6744 to Squid until there is some data to process.
6745 See the accf_dataready(9) man page for details.
6749 The 'data' filter delays delivering of new connections
6750 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
6751 You may optionally specify a number of seconds to wait by
6752 'data=N' where N is the number of seconds. Defaults to 30
6753 if not specified. See the tcp(7) man page for details.
6756 accept_filter httpready
6761 NAME: client_ip_max_connections
6763 LOC: Config.client_ip_max_connections
6766 Set an absolute limit on the number of connections a single
6767 client IP can use. Any more than this and Squid will begin to drop
6768 new connections from the client until it closes some links.
6770 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
6771 connections from the client. For finer control use the ACL access controls.
6773 Requires client_db to be enabled (the default).
6775 WARNING: This may noticably slow down traffic received via external proxies
6776 or NAT devices and cause them to rebound error messages back to their clients.
6779 NAME: tcp_recv_bufsize
6783 LOC: Config.tcpRcvBufsz
6785 Size of receive buffer to set for TCP sockets. Probably just
6786 as easy to change your kernel's default. Set to zero to use
6787 the default buffer size.
6792 -----------------------------------------------------------------------------
6799 LOC: Adaptation::Icap::TheConfig.onoff
6802 If you want to enable the ICAP module support, set this to on.
6805 NAME: icap_connect_timeout
6808 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
6811 This parameter specifies how long to wait for the TCP connect to
6812 the requested ICAP server to complete before giving up and either
6813 terminating the HTTP transaction or bypassing the failure.
6815 The default for optional services is peer_connect_timeout.
6816 The default for essential services is connect_timeout.
6817 If this option is explicitly set, its value applies to all services.
6820 NAME: icap_io_timeout
6824 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
6827 This parameter specifies how long to wait for an I/O activity on
6828 an established, active ICAP connection before giving up and
6829 either terminating the HTTP transaction or bypassing the
6832 The default is read_timeout.
6835 NAME: icap_service_failure_limit
6836 COMMENT: limit [in memory-depth time-units]
6837 TYPE: icap_service_failure_limit
6839 LOC: Adaptation::Icap::TheConfig
6842 The limit specifies the number of failures that Squid tolerates
6843 when establishing a new TCP connection with an ICAP service. If
6844 the number of failures exceeds the limit, the ICAP service is
6845 not used for new ICAP requests until it is time to refresh its
6848 A negative value disables the limit. Without the limit, an ICAP
6849 service will not be considered down due to connectivity failures
6850 between ICAP OPTIONS requests.
6852 Squid forgets ICAP service failures older than the specified
6853 value of memory-depth. The memory fading algorithm
6854 is approximate because Squid does not remember individual
6855 errors but groups them instead, splitting the option
6856 value into ten time slots of equal length.
6858 When memory-depth is 0 and by default this option has no
6859 effect on service failure expiration.
6861 Squid always forgets failures when updating service settings
6862 using an ICAP OPTIONS transaction, regardless of this option
6866 # suspend service usage after 10 failures in 5 seconds:
6867 icap_service_failure_limit 10 in 5 seconds
6870 NAME: icap_service_revival_delay
6873 LOC: Adaptation::Icap::TheConfig.service_revival_delay
6876 The delay specifies the number of seconds to wait after an ICAP
6877 OPTIONS request failure before requesting the options again. The
6878 failed ICAP service is considered "down" until fresh OPTIONS are
6881 The actual delay cannot be smaller than the hardcoded minimum
6882 delay of 30 seconds.
6885 NAME: icap_preview_enable
6889 LOC: Adaptation::Icap::TheConfig.preview_enable
6892 The ICAP Preview feature allows the ICAP server to handle the
6893 HTTP message by looking only at the beginning of the message body
6894 or even without receiving the body at all. In some environments,
6895 previews greatly speedup ICAP processing.
6897 During an ICAP OPTIONS transaction, the server may tell Squid what
6898 HTTP messages should be previewed and how big the preview should be.
6899 Squid will not use Preview if the server did not request one.
6901 To disable ICAP Preview for all ICAP services, regardless of
6902 individual ICAP server OPTIONS responses, set this option to "off".
6904 icap_preview_enable off
6907 NAME: icap_preview_size
6910 LOC: Adaptation::Icap::TheConfig.preview_size
6913 The default size of preview data to be sent to the ICAP server.
6914 -1 means no preview. This value might be overwritten on a per server
6915 basis by OPTIONS requests.
6918 NAME: icap_206_enable
6922 LOC: Adaptation::Icap::TheConfig.allow206_enable
6925 206 (Partial Content) responses is an ICAP extension that allows the
6926 ICAP agents to optionally combine adapted and original HTTP message
6927 content. The decision to combine is postponed until the end of the
6928 ICAP response. Squid supports Partial Content extension by default.
6930 Activation of the Partial Content extension is negotiated with each
6931 ICAP service during OPTIONS exchange. Most ICAP servers should handle
6932 negotation correctly even if they do not support the extension, but
6933 some might fail. To disable Partial Content support for all ICAP
6934 services and to avoid any negotiation, set this option to "off".
6940 NAME: icap_default_options_ttl
6943 LOC: Adaptation::Icap::TheConfig.default_options_ttl
6946 The default TTL value for ICAP OPTIONS responses that don't have
6947 an Options-TTL header.
6950 NAME: icap_persistent_connections
6954 LOC: Adaptation::Icap::TheConfig.reuse_connections
6957 Whether or not Squid should use persistent connections to
6961 NAME: adaptation_send_client_ip icap_send_client_ip
6963 IFDEF: USE_ADAPTATION
6965 LOC: Adaptation::Config::send_client_ip
6968 If enabled, Squid shares HTTP client IP information with adaptation
6969 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
6970 For eCAP, Squid sets the libecap::metaClientIp transaction option.
6972 See also: adaptation_uses_indirect_client
6975 NAME: adaptation_send_username icap_send_client_username
6977 IFDEF: USE_ADAPTATION
6979 LOC: Adaptation::Config::send_username
6982 This sends authenticated HTTP client username (if available) to
6983 the adaptation service.
6985 For ICAP, the username value is encoded based on the
6986 icap_client_username_encode option and is sent using the header
6987 specified by the icap_client_username_header option.
6990 NAME: icap_client_username_header
6993 LOC: Adaptation::Icap::TheConfig.client_username_header
6994 DEFAULT: X-Client-Username
6996 ICAP request header name to use for adaptation_send_username.
6999 NAME: icap_client_username_encode
7003 LOC: Adaptation::Icap::TheConfig.client_username_encode
7006 Whether to base64 encode the authenticated client username.
7010 TYPE: icap_service_type
7012 LOC: Adaptation::Icap::TheConfig
7015 Defines a single ICAP service using the following format:
7017 icap_service id vectoring_point uri [option ...]
7020 an opaque identifier or name which is used to direct traffic to
7021 this specific service. Must be unique among all adaptation
7022 services in squid.conf.
7024 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7025 This specifies at which point of transaction processing the
7026 ICAP service should be activated. *_postcache vectoring points
7027 are not yet supported.
7029 uri: icap://servername:port/servicepath
7030 ICAP server and service location.
7032 ICAP does not allow a single service to handle both REQMOD and RESPMOD
7033 transactions. Squid does not enforce that requirement. You can specify
7034 services with the same service_url and different vectoring_points. You
7035 can even specify multiple identical services as long as their
7036 service_names differ.
7039 Service options are separated by white space. ICAP services support
7040 the following name=value options:
7043 If set to 'on' or '1', the ICAP service is treated as
7044 optional. If the service cannot be reached or malfunctions,
7045 Squid will try to ignore any errors and process the message as
7046 if the service was not enabled. No all ICAP errors can be
7047 bypassed. If set to 0, the ICAP service is treated as
7048 essential and all ICAP errors will result in an error page
7049 returned to the HTTP client.
7051 Bypass is off by default: services are treated as essential.
7054 If set to 'on' or '1', the ICAP service is allowed to
7055 dynamically change the current message adaptation plan by
7056 returning a chain of services to be used next. The services
7057 are specified using the X-Next-Services ICAP response header
7058 value, formatted as a comma-separated list of service names.
7059 Each named service should be configured in squid.conf. Other
7060 services are ignored. An empty X-Next-Services value results
7061 in an empty plan which ends the current adaptation.
7063 Dynamic adaptation plan may cross or cover multiple supported
7064 vectoring points in their natural processing order.
7066 Routing is not allowed by default: the ICAP X-Next-Services
7067 response header is ignored.
7070 Only has effect on split-stack systems. The default on those systems
7071 is to use IPv4-only connections. When set to 'on' this option will
7072 make Squid use IPv6-only connections to contact this ICAP service.
7074 on-overload=block|bypass|wait|force
7075 If the service Max-Connections limit has been reached, do
7076 one of the following for each new ICAP transaction:
7077 * block: send an HTTP error response to the client
7078 * bypass: ignore the "over-connected" ICAP service
7079 * wait: wait (in a FIFO queue) for an ICAP connection slot
7080 * force: proceed, ignoring the Max-Connections limit
7082 In SMP mode with N workers, each worker assumes the service
7083 connection limit is Max-Connections/N, even though not all
7084 workers may use a given service.
7086 The default value is "bypass" if service is bypassable,
7087 otherwise it is set to "wait".
7091 Use the given number as the Max-Connections limit, regardless
7092 of the Max-Connections value given by the service, if any.
7094 Older icap_service format without optional named parameters is
7095 deprecated but supported for backward compatibility.
7098 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
7099 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
7103 TYPE: icap_class_type
7108 This deprecated option was documented to define an ICAP service
7109 chain, even though it actually defined a set of similar, redundant
7110 services, and the chains were not supported.
7112 To define a set of redundant services, please use the
7113 adaptation_service_set directive. For service chains, use
7114 adaptation_service_chain.
7118 TYPE: icap_access_type
7123 This option is deprecated. Please use adaptation_access, which
7124 has the same ICAP functionality, but comes with better
7125 documentation, and eCAP support.
7130 -----------------------------------------------------------------------------
7137 LOC: Adaptation::Ecap::TheConfig.onoff
7140 Controls whether eCAP support is enabled.
7144 TYPE: ecap_service_type
7146 LOC: Adaptation::Ecap::TheConfig
7149 Defines a single eCAP service
7151 ecap_service id vectoring_point uri [option ...]
7154 an opaque identifier or name which is used to direct traffic to
7155 this specific service. Must be unique among all adaptation
7156 services in squid.conf.
7158 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7159 This specifies at which point of transaction processing the
7160 eCAP service should be activated. *_postcache vectoring points
7161 are not yet supported.
7163 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
7164 Squid uses the eCAP service URI to match this configuration
7165 line with one of the dynamically loaded services. Each loaded
7166 eCAP service must have a unique URI. Obtain the right URI from
7167 the service provider.
7170 Service options are separated by white space. eCAP services support
7171 the following name=value options:
7174 If set to 'on' or '1', the eCAP service is treated as optional.
7175 If the service cannot be reached or malfunctions, Squid will try
7176 to ignore any errors and process the message as if the service
7177 was not enabled. No all eCAP errors can be bypassed.
7178 If set to 'off' or '0', the eCAP service is treated as essential
7179 and all eCAP errors will result in an error page returned to the
7182 Bypass is off by default: services are treated as essential.
7185 If set to 'on' or '1', the eCAP service is allowed to
7186 dynamically change the current message adaptation plan by
7187 returning a chain of services to be used next.
7189 Dynamic adaptation plan may cross or cover multiple supported
7190 vectoring points in their natural processing order.
7192 Routing is not allowed by default.
7194 Older ecap_service format without optional named parameters is
7195 deprecated but supported for backward compatibility.
7199 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
7200 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
7203 NAME: loadable_modules
7205 IFDEF: USE_LOADABLE_MODULES
7206 LOC: Config.loadable_module_names
7209 Instructs Squid to load the specified dynamic module(s) or activate
7210 preloaded module(s).
7212 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
7216 MESSAGE ADAPTATION OPTIONS
7217 -----------------------------------------------------------------------------
7220 NAME: adaptation_service_set
7221 TYPE: adaptation_service_set_type
7222 IFDEF: USE_ADAPTATION
7227 Configures an ordered set of similar, redundant services. This is
7228 useful when hot standby or backup adaptation servers are available.
7230 adaptation_service_set set_name service_name1 service_name2 ...
7232 The named services are used in the set declaration order. The first
7233 applicable adaptation service from the set is used first. The next
7234 applicable service is tried if and only if the transaction with the
7235 previous service fails and the message waiting to be adapted is still
7238 When adaptation starts, broken services are ignored as if they were
7239 not a part of the set. A broken service is a down optional service.
7241 The services in a set must be attached to the same vectoring point
7242 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7244 If all services in a set are optional then adaptation failures are
7245 bypassable. If all services in the set are essential, then a
7246 transaction failure with one service may still be retried using
7247 another service from the set, but when all services fail, the master
7248 transaction fails as well.
7250 A set may contain a mix of optional and essential services, but that
7251 is likely to lead to surprising results because broken services become
7252 ignored (see above), making previously bypassable failures fatal.
7253 Technically, it is the bypassability of the last failed service that
7256 See also: adaptation_access adaptation_service_chain
7259 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
7260 adaptation service_set svcLogger loggerLocal loggerRemote
7263 NAME: adaptation_service_chain
7264 TYPE: adaptation_service_chain_type
7265 IFDEF: USE_ADAPTATION
7270 Configures a list of complementary services that will be applied
7271 one-by-one, forming an adaptation chain or pipeline. This is useful
7272 when Squid must perform different adaptations on the same message.
7274 adaptation_service_chain chain_name service_name1 svc_name2 ...
7276 The named services are used in the chain declaration order. The first
7277 applicable adaptation service from the chain is used first. The next
7278 applicable service is applied to the successful adaptation results of
7279 the previous service in the chain.
7281 When adaptation starts, broken services are ignored as if they were
7282 not a part of the chain. A broken service is a down optional service.
7284 Request satisfaction terminates the adaptation chain because Squid
7285 does not currently allow declaration of RESPMOD services at the
7286 "reqmod_precache" vectoring point (see icap_service or ecap_service).
7288 The services in a chain must be attached to the same vectoring point
7289 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7291 A chain may contain a mix of optional and essential services. If an
7292 essential adaptation fails (or the failure cannot be bypassed for
7293 other reasons), the master transaction fails. Otherwise, the failure
7294 is bypassed as if the failed adaptation service was not in the chain.
7296 See also: adaptation_access adaptation_service_set
7299 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
7302 NAME: adaptation_access
7303 TYPE: adaptation_access_type
7304 IFDEF: USE_ADAPTATION
7308 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
7310 adaptation_access service_name allow|deny [!]aclname...
7311 adaptation_access set_name allow|deny [!]aclname...
7313 At each supported vectoring point, the adaptation_access
7314 statements are processed in the order they appear in this
7315 configuration file. Statements pointing to the following services
7316 are ignored (i.e., skipped without checking their ACL):
7318 - services serving different vectoring points
7319 - "broken-but-bypassable" services
7320 - "up" services configured to ignore such transactions
7321 (e.g., based on the ICAP Transfer-Ignore header).
7323 When a set_name is used, all services in the set are checked
7324 using the same rules, to find the first applicable one. See
7325 adaptation_service_set for details.
7327 If an access list is checked and there is a match, the
7328 processing stops: For an "allow" rule, the corresponding
7329 adaptation service is used for the transaction. For a "deny"
7330 rule, no adaptation service is activated.
7332 It is currently not possible to apply more than one adaptation
7333 service at the same vectoring point to the same HTTP transaction.
7335 See also: icap_service and ecap_service
7338 adaptation_access service_1 allow all
7341 NAME: adaptation_service_iteration_limit
7343 IFDEF: USE_ADAPTATION
7344 LOC: Adaptation::Config::service_iteration_limit
7347 Limits the number of iterations allowed when applying adaptation
7348 services to a message. If your longest adaptation set or chain
7349 may have more than 16 services, increase the limit beyond its
7350 default value of 16. If detecting infinite iteration loops sooner
7351 is critical, make the iteration limit match the actual number
7352 of services in your longest adaptation set or chain.
7354 Infinite adaptation loops are most likely with routing services.
7356 See also: icap_service routing=1
7359 NAME: adaptation_masterx_shared_names
7361 IFDEF: USE_ADAPTATION
7362 LOC: Adaptation::Config::masterx_shared_name
7365 For each master transaction (i.e., the HTTP request and response
7366 sequence, including all related ICAP and eCAP exchanges), Squid
7367 maintains a table of metadata. The table entries are (name, value)
7368 pairs shared among eCAP and ICAP exchanges. The table is destroyed
7369 with the master transaction.
7371 This option specifies the table entry names that Squid must accept
7372 from and forward to the adaptation transactions.
7374 An ICAP REQMOD or RESPMOD transaction may set an entry in the
7375 shared table by returning an ICAP header field with a name
7376 specified in adaptation_masterx_shared_names.
7378 An eCAP REQMOD or RESPMOD transaction may set an entry in the
7379 shared table by implementing the libecap::visitEachOption() API
7380 to provide an option with a name specified in
7381 adaptation_masterx_shared_names.
7383 Squid will store and forward the set entry to subsequent adaptation
7384 transactions within the same master transaction scope.
7386 Only one shared entry name is supported at this time.
7389 # share authentication information among ICAP services
7390 adaptation_masterx_shared_names X-Subscriber-ID
7393 NAME: adaptation_meta
7394 TYPE: adaptation_meta_type
7395 IFDEF: USE_ADAPTATION
7396 LOC: Adaptation::Config::metaHeaders
7399 This option allows Squid administrator to add custom ICAP request
7400 headers or eCAP options to Squid ICAP requests or eCAP transactions.
7401 Use it to pass custom authentication tokens and other
7402 transaction-state related meta information to an ICAP/eCAP service.
7404 The addition of a meta header is ACL-driven:
7405 adaptation_meta name value [!]aclname ...
7407 Processing for a given header name stops after the first ACL list match.
7408 Thus, it is impossible to add two headers with the same name. If no ACL
7409 lists match for a given header name, no such header is added. For
7412 # do not debug transactions except for those that need debugging
7413 adaptation_meta X-Debug 1 needs_debugging
7415 # log all transactions except for those that must remain secret
7416 adaptation_meta X-Log 1 !keep_secret
7418 # mark transactions from users in the "G 1" group
7419 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
7421 The "value" parameter may be a regular squid.conf token or a "double
7422 quoted string". Within the quoted string, use backslash (\) to escape
7423 any character, which is currently only useful for escaping backslashes
7424 and double quotes. For example,
7425 "this string has one backslash (\\) and two \"quotes\""
7431 LOC: Adaptation::Icap::TheConfig.repeat
7432 DEFAULT_IF_NONE: deny all
7434 This ACL determines which retriable ICAP transactions are
7435 retried. Transactions that received a complete ICAP response
7436 and did not have to consume or produce HTTP bodies to receive
7437 that response are usually retriable.
7439 icap_retry allow|deny [!]aclname ...
7441 Squid automatically retries some ICAP I/O timeouts and errors
7442 due to persistent connection race conditions.
7444 See also: icap_retry_limit
7447 NAME: icap_retry_limit
7450 LOC: Adaptation::Icap::TheConfig.repeat_limit
7453 Limits the number of retries allowed. When set to zero (default),
7454 no retries are allowed.
7456 Communication errors due to persistent connection race
7457 conditions are unavoidable, automatically retried, and do not
7458 count against this limit.
7460 See also: icap_retry
7466 -----------------------------------------------------------------------------
7469 NAME: check_hostnames
7472 LOC: Config.onoff.check_hostnames
7474 For security and stability reasons Squid can check
7475 hostnames for Internet standard RFC compliance. If you want
7476 Squid to perform these checks turn this directive on.
7479 NAME: allow_underscore
7482 LOC: Config.onoff.allow_underscore
7484 Underscore characters is not strictly allowed in Internet hostnames
7485 but nevertheless used by many sites. Set this to off if you want
7486 Squid to be strict about the standard.
7487 This check is performed only when check_hostnames is set to on.
7490 NAME: cache_dns_program
7492 IFDEF: USE_DNSHELPER
7493 DEFAULT: @DEFAULT_DNSSERVER@
7494 LOC: Config.Program.dnsserver
7496 Specify the location of the executable for dnslookup process.
7500 TYPE: HelperChildConfig
7501 IFDEF: USE_DNSHELPER
7502 DEFAULT: 32 startup=1 idle=1
7503 LOC: Config.dnsChildren
7505 The maximum number of processes spawn to service DNS name lookups.
7506 If you limit it too few Squid will have to wait for them to process
7507 a backlog of requests, slowing it down. If you allow too many they
7508 will use RAM and other system resources noticably.
7509 The maximum this may be safely set to is 32.
7511 The startup= and idle= options allow some measure of skew in your
7516 Sets a minimum of how many processes are to be spawned when Squid
7517 starts or reconfigures. When set to zero the first request will
7518 cause spawning of the first child process to handle it.
7520 Starting too few will cause an initial slowdown in traffic as Squid
7521 attempts to simultaneously spawn enough processes to cope.
7525 Sets a minimum of how many processes Squid is to try and keep available
7526 at all times. When traffic begins to rise above what the existing
7527 processes can handle this many more will be spawned up to the maximum
7528 configured. A minimum setting of 1 is required.
7531 NAME: dns_retransmit_interval
7534 LOC: Config.Timeout.idns_retransmit
7535 IFDEF: !USE_DNSHELPER
7537 Initial retransmit interval for DNS queries. The interval is
7538 doubled each time all configured DNS servers have been tried.
7544 LOC: Config.Timeout.idns_query
7545 IFDEF: !USE_DNSHELPER
7547 DNS Query timeout. If no response is received to a DNS query
7548 within this time all DNS servers for the queried domain
7549 are assumed to be unavailable.
7552 NAME: dns_packet_max
7555 LOC: Config.dns.packet_max
7556 IFDEF: !USE_DNSHELPER
7558 Maximum number of bytes packet size to advertise via EDNS.
7559 Set to "none" to disable EDNS large packet support.
7561 For legacy reasons DNS UDP replies will default to 512 bytes which
7562 is too small for many responses. EDNS provides a means for Squid to
7563 negotiate receiving larger responses back immediately without having
7564 to failover with repeat requests. Responses larger than this limit
7565 will retain the old behaviour of failover to TCP DNS.
7567 Squid has no real fixed limit internally, but allowing packet sizes
7568 over 1500 bytes requires network jumbogram support and is usually not
7571 WARNING: The RFC also indicates that some older resolvers will reply
7572 with failure of the whole request if the extension is added. Some
7573 resolvers have already been identified which will reply with mangled
7574 EDNS response on occasion. Usually in response to many-KB jumbogram
7575 sizes being advertised by Squid.
7576 Squid will currently treat these both as an unable-to-resolve domain
7577 even if it would be resolvable without EDNS.
7584 LOC: Config.onoff.res_defnames
7586 Normally the RES_DEFNAMES resolver option is disabled
7587 (see res_init(3)). This prevents caches in a hierarchy
7588 from interpreting single-component hostnames locally. To allow
7589 Squid to handle single-component names, enable this option.
7592 NAME: dns_nameservers
7595 LOC: Config.dns_nameservers
7597 Use this if you want to specify a list of DNS name servers
7598 (IP addresses) to use instead of those given in your
7599 /etc/resolv.conf file.
7600 On Windows platforms, if no value is specified here or in
7601 the /etc/resolv.conf file, the list of DNS name servers are
7602 taken from the Windows registry, both static and dynamic DHCP
7603 configurations are supported.
7605 Example: dns_nameservers 10.0.0.1 192.172.0.4
7610 DEFAULT: @DEFAULT_HOSTS@
7611 LOC: Config.etcHostsPath
7613 Location of the host-local IP name-address associations
7614 database. Most Operating Systems have such a file on different
7616 - Un*X & Linux: /etc/hosts
7617 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
7618 (%SystemRoot% value install default is c:\winnt)
7619 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
7620 (%SystemRoot% value install default is c:\windows)
7621 - Windows 9x/Me: %windir%\hosts
7622 (%windir% value is usually c:\windows)
7623 - Cygwin: /etc/hosts
7625 The file contains newline-separated definitions, in the
7626 form ip_address_in_dotted_form name [name ...] names are
7627 whitespace-separated. Lines beginning with an hash (#)
7628 character are comments.
7630 The file is checked at startup and upon configuration.
7631 If set to 'none', it won't be checked.
7632 If append_domain is used, that domain will be added to
7633 domain-local (i.e. not containing any dot character) host
7639 LOC: Config.appendDomain
7642 Appends local domain name to hostnames without any dots in
7643 them. append_domain must begin with a period.
7645 Be warned there are now Internet names with no dots in
7646 them using only top-domain names, so setting this may
7647 cause some Internet sites to become unavailable.
7650 append_domain .yourdomain.com
7653 NAME: ignore_unknown_nameservers
7655 LOC: Config.onoff.ignore_unknown_nameservers
7657 IFDEF: !USE_DNSHELPER
7659 By default Squid checks that DNS responses are received
7660 from the same IP addresses they are sent to. If they
7661 don't match, Squid ignores the response and writes a warning
7662 message to cache.log. You can allow responses from unknown
7663 nameservers by setting this option to 'off'.
7669 LOC: Config.dns.v4_first
7670 IFDEF: !USE_DNSHELPER
7672 With the IPv6 Internet being as fast or faster than IPv4 Internet
7673 for most networks Squid prefers to contact websites over IPv6.
7675 This option reverses the order of preference to make Squid contact
7676 dual-stack websites over IPv4 first. Squid will still perform both
7677 IPv6 and IPv4 DNS lookups before connecting.
7680 This option will restrict the situations under which IPv6
7681 connectivity is used (and tested). Hiding network problems
7682 which would otherwise be detected and warned about.
7686 COMMENT: (number of entries)
7689 LOC: Config.ipcache.size
7696 LOC: Config.ipcache.low
7703 LOC: Config.ipcache.high
7705 The size, low-, and high-water marks for the IP cache.
7708 NAME: fqdncache_size
7709 COMMENT: (number of entries)
7712 LOC: Config.fqdncache.size
7714 Maximum number of FQDN cache entries.
7719 -----------------------------------------------------------------------------
7726 LOC: Config.onoff.mem_pools
7728 If set, Squid will keep pools of allocated (but unused) memory
7729 available for future use. If memory is a premium on your
7730 system and you believe your malloc library outperforms Squid
7731 routines, disable this.
7734 NAME: memory_pools_limit
7738 LOC: Config.MemPools.limit
7740 Used only with memory_pools on:
7741 memory_pools_limit 50 MB
7743 If set to a non-zero value, Squid will keep at most the specified
7744 limit of allocated (but unused) memory in memory pools. All free()
7745 requests that exceed this limit will be handled by your malloc
7746 library. Squid does not pre-allocate any memory, just safe-keeps
7747 objects that otherwise would be free()d. Thus, it is safe to set
7748 memory_pools_limit to a reasonably high value even if your
7749 configuration will use less memory.
7751 If set to none, Squid will keep all memory it can. That is, there
7752 will be no limit on the total amount of memory used for safe-keeping.
7754 To disable memory allocation optimization, do not set
7755 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
7757 An overhead for maintaining memory pools is not taken into account
7758 when the limit is checked. This overhead is close to four bytes per
7759 object kept. However, pools may actually _save_ memory because of
7760 reduced memory thrashing in your malloc library.
7764 COMMENT: on|off|transparent|truncate|delete
7767 LOC: opt_forwarded_for
7769 If set to "on", Squid will append your client's IP address
7770 in the HTTP requests it forwards. By default it looks like:
7772 X-Forwarded-For: 192.1.2.3
7774 If set to "off", it will appear as
7776 X-Forwarded-For: unknown
7778 If set to "transparent", Squid will not alter the
7779 X-Forwarded-For header in any way.
7781 If set to "delete", Squid will delete the entire
7782 X-Forwarded-For header.
7784 If set to "truncate", Squid will remove all existing
7785 X-Forwarded-For entries, and place the client IP as the sole entry.
7788 NAME: cachemgr_passwd
7789 TYPE: cachemgrpasswd
7791 LOC: Config.passwd_list
7793 Specify passwords for cachemgr operations.
7795 Usage: cachemgr_passwd password action action ...
7797 Some valid actions are (see cache manager menu for a full list):
7837 * Indicates actions which will not be performed without a
7838 valid password, others can be performed if not listed here.
7840 To disable an action, set the password to "disable".
7841 To allow performing an action without a password, set the
7844 Use the keyword "all" to set the same password for all actions.
7847 cachemgr_passwd secret shutdown
7848 cachemgr_passwd lesssssssecret info stats/objects
7849 cachemgr_passwd disable all
7856 LOC: Config.onoff.client_db
7858 If you want to disable collecting per-client statistics,
7859 turn off client_db here.
7862 NAME: refresh_all_ims
7866 LOC: Config.onoff.refresh_all_ims
7868 When you enable this option, squid will always check
7869 the origin server for an update when a client sends an
7870 If-Modified-Since request. Many browsers use IMS
7871 requests when the user requests a reload, and this
7872 ensures those clients receive the latest version.
7874 By default (off), squid may return a Not Modified response
7875 based on the age of the cached version.
7878 NAME: reload_into_ims
7879 IFDEF: USE_HTTP_VIOLATIONS
7883 LOC: Config.onoff.reload_into_ims
7885 When you enable this option, client no-cache or ``reload''
7886 requests will be changed to If-Modified-Since requests.
7887 Doing this VIOLATES the HTTP standard. Enabling this
7888 feature could make you liable for problems which it
7891 see also refresh_pattern for a more selective approach.
7894 NAME: connect_retries
7896 LOC: Config.connect_retries
7899 This sets the maximum number of connection attempts made for each
7900 TCP connection. The connect_retries attempts must all still
7901 complete within the connection timeout period.
7903 The default is not to re-try if the first connection attempt fails.
7904 The (not recommended) maximum is 10 tries.
7906 A warning message will be generated if it is set to a too-high
7907 value and the configured value will be over-ridden.
7909 Note: These re-tries are in addition to forward_max_tries
7910 which limit how many different addresses may be tried to find
7914 NAME: retry_on_error
7916 LOC: Config.retry.onerror
7919 If set to ON Squid will automatically retry requests when
7920 receiving an error response with status 403 (Forbidden),
7921 500 (Internal Error), 501 or 503 (Service not available).
7922 Status 502 and 504 (Gateway errors) are always retried.
7924 This is mainly useful if you are in a complex cache hierarchy to
7925 work around access control errors.
7927 NOTE: This retry will attempt to find another working destination.
7928 Which is different from the server which just failed.
7931 NAME: as_whois_server
7933 LOC: Config.as_whois_server
7934 DEFAULT: whois.ra.net
7936 WHOIS server to query for AS numbers. NOTE: AS numbers are
7937 queried only when Squid starts up, not for every request.
7942 LOC: Config.onoff.offline
7945 Enable this option and Squid will never try to validate cached
7949 NAME: uri_whitespace
7950 TYPE: uri_whitespace
7951 LOC: Config.uri_whitespace
7954 What to do with requests that have whitespace characters in the
7957 strip: The whitespace characters are stripped out of the URL.
7958 This is the behavior recommended by RFC2396.
7959 deny: The request is denied. The user receives an "Invalid
7961 allow: The request is allowed and the URI is not changed. The
7962 whitespace characters remain in the URI. Note the
7963 whitespace is passed to redirector processes if they
7965 encode: The request is allowed and the whitespace characters are
7966 encoded according to RFC1738. This could be considered
7967 a violation of the HTTP/1.1
7968 RFC because proxies are not allowed to rewrite URI's.
7969 chop: The request is allowed and the URI is chopped at the
7970 first whitespace. This might also be considered a
7976 LOC: Config.chroot_dir
7979 Specifies a directory where Squid should do a chroot() while
7980 initializing. This also causes Squid to fully drop root
7981 privileges after initializing. This means, for example, if you
7982 use a HTTP port less than 1024 and try to reconfigure, you may
7983 get an error saying that Squid can not open the port.
7986 NAME: balance_on_multiple_ip
7988 LOC: Config.onoff.balance_on_multiple_ip
7991 Modern IP resolvers in squid sort lookup results by preferred access.
7992 By default squid will use these IP in order and only rotates to
7993 the next listed when the most preffered fails.
7995 Some load balancing servers based on round robin DNS have been
7996 found not to preserve user session state across requests
7997 to different IP addresses.
7999 Enabling this directive Squid rotates IP's per request.
8002 NAME: pipeline_prefetch
8004 LOC: Config.onoff.pipeline_prefetch
8007 To boost the performance of pipelined requests to closer
8008 match that of a non-proxied environment Squid can try to fetch
8009 up to two requests in parallel from a pipeline.
8011 Defaults to off for bandwidth management and access logging
8014 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
8017 NAME: high_response_time_warning
8020 LOC: Config.warnings.high_rptm
8023 If the one-minute median response time exceeds this value,
8024 Squid prints a WARNING with debug level 0 to get the
8025 administrators attention. The value is in milliseconds.
8028 NAME: high_page_fault_warning
8030 LOC: Config.warnings.high_pf
8033 If the one-minute average page fault rate exceeds this
8034 value, Squid prints a WARNING with debug level 0 to get
8035 the administrators attention. The value is in page faults
8039 NAME: high_memory_warning
8041 LOC: Config.warnings.high_memory
8044 If the memory usage (as determined by mallinfo) exceeds
8045 this amount, Squid prints a WARNING with debug level 0 to get
8046 the administrators attention.
8049 NAME: sleep_after_fork
8050 COMMENT: (microseconds)
8052 LOC: Config.sleep_after_fork
8055 When this is set to a non-zero value, the main Squid process
8056 sleeps the specified number of microseconds after a fork()
8057 system call. This sleep may help the situation where your
8058 system reports fork() failures due to lack of (virtual)
8059 memory. Note, however, if you have a lot of child
8060 processes, these sleep delays will add up and your
8061 Squid will not service requests for some amount of time
8062 until all the child processes have been started.
8063 On Windows value less then 1000 (1 milliseconds) are
8067 NAME: windows_ipaddrchangemonitor
8068 IFDEF: _SQUID_MSWIN_
8072 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
8074 On Windows Squid by default will monitor IP address changes and will
8075 reconfigure itself after any detected event. This is very useful for
8076 proxies connected to internet with dial-up interfaces.
8077 In some cases (a Proxy server acting as VPN gateway is one) it could be
8078 desiderable to disable this behaviour setting this to 'off'.
8079 Note: after changing this, Squid service must be restarted.
8084 IFDEF: USE_SQUID_EUI
8086 LOC: Eui::TheConfig.euiLookup
8088 Whether to lookup the EUI or MAC address of a connected client.
8091 NAME: max_filedescriptors max_filedesc
8094 LOC: Config.max_filedescriptors
8096 The maximum number of filedescriptors supported.
8098 The default "0" means Squid inherits the current ulimit setting.
8100 Note: Changing this requires a restart of Squid. Also
8101 not all comm loops supports large values.
8109 Number of main Squid processes or "workers" to fork and maintain.
8110 0: "no daemon" mode, like running "squid -N ..."
8111 1: "no SMP" mode, start one main Squid process daemon (default)
8112 N: start N main Squid process daemons (i.e., SMP mode)
8114 In SMP mode, each worker does nearly all what a single Squid daemon
8115 does (e.g., listen on http_port and forward HTTP requests).
8118 NAME: cpu_affinity_map
8119 TYPE: CpuAffinityMap
8120 LOC: Config.cpuAffinityMap
8123 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
8125 Sets 1:1 mapping between Squid processes and CPU cores. For example,
8127 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
8129 affects processes 1 through 4 only and places them on the first
8130 four even cores, starting with core #1.
8132 CPU cores are numbered starting from 1. Requires support for
8133 sched_getaffinity(2) and sched_setaffinity(2) system calls.
8135 Multiple cpu_affinity_map options are merged.
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