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: maximum_single_addr_tries
129 Replaced by connect_retries. The behaviour has changed, please read the documentation before altering.
132 NAME: url_rewrite_concurrency
135 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
138 # Options Removed in 3.1
142 Remove this line. DNS is no longer tested on startup.
145 NAME: extension_methods
148 Remove this line. All valid methods for HTTP are accepted by default.
151 # 2.7 Options Removed/Replaced in 3.2
156 # 2.7 Options Removed/Replaced in 3.1
164 Remove this line. HTTP/1.1 is supported by default.
167 NAME: upgrade_http0.9
170 Remove this line. ICY/1.0 streaming protocol is supported by default.
173 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
176 Alter these entries. Use the qos_flows directive instead.
179 # Options Removed in 3.0
183 Since squid-3.0 replace with request_header_access or reply_header_access
184 depending on whether you wish to match client requests or server replies.
187 NAME: httpd_accel_no_pmtu_disc
190 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
194 OPTIONS FOR AUTHENTICATION
195 -----------------------------------------------------------------------------
204 This is used to define parameters for the various authentication
205 schemes supported by Squid.
207 format: auth_param scheme parameter [setting]
209 The order in which authentication schemes are presented to the client is
210 dependent on the order the scheme first appears in config file. IE
211 has a bug (it's not RFC 2617 compliant) in that it will use the basic
212 scheme if basic is the first entry presented, even if more secure
213 schemes are presented. For now use the order in the recommended
214 settings section below. If other browsers have difficulties (don't
215 recognize the schemes offered even if you are using basic) either
216 put basic first, or disable the other schemes (by commenting out their
219 Once an authentication scheme is fully configured, it can only be
220 shutdown by shutting squid down and restarting. Changes can be made on
221 the fly and activated with a reconfigure. I.E. You can change to a
222 different helper, but not unconfigure the helper completely.
224 Please note that while this directive defines how Squid processes
225 authentication it does not automatically activate authentication.
226 To use authentication you must in addition make use of ACLs based
227 on login name in http_access (proxy_auth, proxy_auth_regex or
228 external with %LOGIN used in the format tag). The browser will be
229 challenged for authentication on the first such acl encountered
230 in http_access processing and will also be re-challenged for new
231 login credentials if the request is being denied by a proxy_auth
234 WARNING: authentication can't be used in a transparently intercepting
235 proxy as the client then thinks it is talking to an origin server and
236 not the proxy. This is a limitation of bending the TCP/IP protocol to
237 transparently intercepting port 80, not a limitation in Squid.
238 Ports flagged 'transparent', 'intercept', or 'tproxy' have
239 authentication disabled.
241 === Parameters for the basic scheme follow. ===
244 Specify the command for the external authenticator. Such a program
245 reads a line containing "username password" and replies "OK" or
246 "ERR" in an endless loop. "ERR" responses may optionally be followed
247 by a error description available as %m in the returned error page.
248 If you use an authenticator, make sure you have 1 acl of type
251 By default, the basic authentication scheme is not used unless a
252 program is specified.
254 If you want to use the traditional NCSA proxy authentication, set
255 this line to something like
257 auth_param basic program @DEFAULT_PREFIX@/libexec/ncsa_auth @DEFAULT_PREFIX@/etc/passwd
260 HTTP uses iso-latin-1 as characterset, while some authentication
261 backends such as LDAP expects UTF-8. If this is set to on Squid will
262 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
263 username & password to the helper.
265 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
266 The maximum number of authenticator processes to spawn. If you start too few
267 Squid will have to wait for them to process a backlog of credential
268 verifications, slowing it down. When password verifications are
269 done via a (slow) network you are likely to need lots of
270 authenticator processes.
272 The startup= and idle= options permit some skew in the exact amount
273 run. A minimum of startup=N will begin during startup and reconfigure.
274 Squid will start more in groups of up to idle=N in an attempt to meet
275 traffic needs and to keep idle=N free above those traffic needs up to
278 The concurrency= option sets the number of concurrent requests the
279 helper can process. The default of 0 is used for helpers who only
280 supports one request at a time. Setting this to a number greater than
281 0 changes the protocol used to include a channel number first on the
282 request/response line, allowing multiple requests to be sent to the
283 same helper in parallell without wating for the response.
284 Must not be set unless it's known the helper supports this.
286 auth_param basic children 20 startup=0 idle=1
289 Specifies the realm name which is to be reported to the
290 client for the basic proxy authentication scheme (part of
291 the text the user will see when prompted their username and
292 password). There is no default.
293 auth_param basic realm Squid proxy-caching web server
295 "credentialsttl" timetolive
296 Specifies how long squid assumes an externally validated
297 username:password pair is valid for - in other words how
298 often the helper program is called for that user. Set this
299 low to force revalidation with short lived passwords. Note
300 setting this high does not impact your susceptibility
301 to replay attacks unless you are using an one-time password
302 system (such as SecureID). If you are using such a system,
303 you will be vulnerable to replay attacks unless you also
304 use the max_user_ip ACL in an http_access rule.
306 "casesensitive" on|off
307 Specifies if usernames are case sensitive. Most user databases are
308 case insensitive allowing the same username to be spelled using both
309 lower and upper case letters, but some are case sensitive. This
310 makes a big difference for user_max_ip ACL processing and similar.
311 auth_param basic casesensitive off
313 === Parameters for the digest scheme follow ===
316 Specify the command for the external authenticator. Such
317 a program reads a line containing "username":"realm" and
318 replies with the appropriate H(A1) value hex encoded or
319 ERR if the user (or his H(A1) hash) does not exists.
320 See rfc 2616 for the definition of H(A1).
321 "ERR" responses may optionally be followed by a error description
322 available as %m in the returned error page.
324 By default, the digest authentication scheme is not used unless a
325 program is specified.
327 If you want to use a digest authenticator, set this line to
330 auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass
333 HTTP uses iso-latin-1 as characterset, while some authentication
334 backends such as LDAP expects UTF-8. If this is set to on Squid will
335 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
336 username & password to the helper.
338 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
339 The maximum number of authenticator processes to spawn (default 5).
340 If you start too few Squid will have to wait for them to
341 process a backlog of H(A1) calculations, slowing it down.
342 When the H(A1) calculations are done via a (slow) network
343 you are likely to need lots of authenticator processes.
345 The startup= and idle= options permit some skew in the exact amount
346 run. A minimum of startup=N will begin during startup and reconfigure.
347 Squid will start more in groups of up to idle=N in an attempt to meet
348 traffic needs and to keep idle=N free above those traffic needs up to
351 The concurrency= option sets the number of concurrent requests the
352 helper can process. The default of 0 is used for helpers who only
353 supports one request at a time. Setting this to a number greater than
354 0 changes the protocol used to include a channel number first on the
355 request/response line, allowing multiple requests to be sent to the
356 same helper in parallell without wating for the response.
357 Must not be set unless it's known the helper supports this.
359 auth_param digest children 20 startup=0 idle=1
362 Specifies the realm name which is to be reported to the
363 client for the digest proxy authentication scheme (part of
364 the text the user will see when prompted their username and
365 password). There is no default.
366 auth_param digest realm Squid proxy-caching web server
368 "nonce_garbage_interval" timeinterval
369 Specifies the interval that nonces that have been issued
370 to client_agent's are checked for validity.
372 "nonce_max_duration" timeinterval
373 Specifies the maximum length of time a given nonce will be
376 "nonce_max_count" number
377 Specifies the maximum number of times a given nonce can be
380 "nonce_strictness" on|off
381 Determines if squid requires strict increment-by-1 behavior
382 for nonce counts, or just incrementing (off - for use when
383 useragents generate nonce counts that occasionally miss 1
384 (ie, 1,2,4,6)). Default off.
386 "check_nonce_count" on|off
387 This directive if set to off can disable the nonce count check
388 completely to work around buggy digest qop implementations in
389 certain mainstream browser versions. Default on to check the
390 nonce count to protect from authentication replay attacks.
392 "post_workaround" on|off
393 This is a workaround to certain buggy browsers who sends
394 an incorrect request digest in POST requests when reusing
395 the same nonce as acquired earlier on a GET request.
397 === NTLM scheme options follow ===
400 Specify the command for the external NTLM authenticator.
401 Such a program reads exchanged NTLMSSP packets with
402 the browser via Squid until authentication is completed.
403 If you use an NTLM authenticator, make sure you have 1 acl
404 of type proxy_auth. By default, the NTLM authenticator_program
407 auth_param ntlm program @DEFAULT_PREFIX@/bin/ntlm_auth
409 "children" numberofchildren [startup=N] [idle=N]
410 The maximum number of authenticator processes to spawn (default 5).
411 If you start too few Squid will have to wait for them to
412 process a backlog of credential verifications, slowing it
413 down. When credential verifications are done via a (slow)
414 network you are likely to need lots of authenticator
417 The startup= and idle= options permit some skew in the exact amount
418 run. A minimum of startup=N will begin during startup and reconfigure.
419 Squid will start more in groups of up to idle=N in an attempt to meet
420 traffic needs and to keep idle=N free above those traffic needs up to
423 auth_param ntlm children 20 startup=0 idle=1
426 If you experience problems with PUT/POST requests when using the
427 Negotiate authentication scheme then you can try setting this to
428 off. This will cause Squid to forcibly close the connection on
429 the initial requests where the browser asks which schemes are
430 supported by the proxy.
432 auth_param ntlm keep_alive on
434 === Options for configuring the NEGOTIATE auth-scheme follow ===
437 Specify the command for the external Negotiate authenticator.
438 This protocol is used in Microsoft Active-Directory enabled setups with
439 the Microsoft Internet Explorer or Mozilla Firefox browsers.
440 Its main purpose is to exchange credentials with the Squid proxy
441 using the Kerberos mechanisms.
442 If you use a Negotiate authenticator, make sure you have at least
443 one acl of type proxy_auth active. By default, the negotiate
444 authenticator_program is not used.
445 The only supported program for this role is the ntlm_auth
446 program distributed as part of Samba, version 4 or later.
448 auth_param negotiate program @DEFAULT_PREFIX@/bin/ntlm_auth --helper-protocol=gss-spnego
450 "children" numberofchildren [startup=N] [idle=N]
451 The maximum number of authenticator processes to spawn (default 5).
452 If you start too few Squid will have to wait for them to
453 process a backlog of credential verifications, slowing it
454 down. When crendential verifications are done via a (slow)
455 network you are likely to need lots of authenticator
458 The startup= and idle= options permit some skew in the exact amount
459 run. A minimum of startup=N will begin during startup and reconfigure.
460 Squid will start more in groups of up to idle=N in an attempt to meet
461 traffic needs and to keep idle=N free above those traffic needs up to
464 auth_param negotiate children 20 startup=0 idle=1
467 If you experience problems with PUT/POST requests when using the
468 Negotiate authentication scheme then you can try setting this to
469 off. This will cause Squid to forcibly close the connection on
470 the initial requests where the browser asks which schemes are
471 supported by the proxy.
473 auth_param negotiate keep_alive on
478 #Recommended minimum configuration per scheme:
479 #auth_param negotiate program <uncomment and complete this line to activate>
480 #auth_param negotiate children 20 startup=0 idle=1
481 #auth_param negotiate keep_alive on
483 #auth_param ntlm program <uncomment and complete this line to activate>
484 #auth_param ntlm children 20 startup=0 idle=1
485 #auth_param ntlm keep_alive on
487 #auth_param digest program <uncomment and complete this line>
488 #auth_param digest children 20 startup=0 idle=1
489 #auth_param digest realm Squid proxy-caching web server
490 #auth_param digest nonce_garbage_interval 5 minutes
491 #auth_param digest nonce_max_duration 30 minutes
492 #auth_param digest nonce_max_count 50
494 #auth_param basic program <uncomment and complete this line>
495 #auth_param basic children 5 startup=5 idle=1
496 #auth_param basic realm Squid proxy-caching web server
497 #auth_param basic credentialsttl 2 hours
500 NAME: authenticate_cache_garbage_interval
503 LOC: Config.authenticateGCInterval
505 The time period between garbage collection across the username cache.
506 This is a tradeoff between memory utilization (long intervals - say
507 2 days) and CPU (short intervals - say 1 minute). Only change if you
511 NAME: authenticate_ttl
514 LOC: Config.authenticateTTL
516 The time a user & their credentials stay in the logged in
517 user cache since their last request. When the garbage
518 interval passes, all user credentials that have passed their
519 TTL are removed from memory.
522 NAME: authenticate_ip_ttl
524 LOC: Config.authenticateIpTTL
527 If you use proxy authentication and the 'max_user_ip' ACL,
528 this directive controls how long Squid remembers the IP
529 addresses associated with each user. Use a small value
530 (e.g., 60 seconds) if your users might change addresses
531 quickly, as is the case with dialups. You might be safe
532 using a larger value (e.g., 2 hours) in a corporate LAN
533 environment with relatively static address assignments.
538 -----------------------------------------------------------------------------
541 NAME: external_acl_type
542 TYPE: externalAclHelper
543 LOC: Config.externalAclHelperList
546 This option defines external acl classes using a helper program
547 to look up the status
549 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
553 ttl=n TTL in seconds for cached results (defaults to 3600
556 TTL for cached negative lookups (default same
559 Maximum number of acl helper processes spawned to service
560 external acl lookups of this type. (default 20)
562 Minimum number of acl helper processes to spawn during
563 startup and reconfigure to service external acl lookups
564 of this type. (default 0)
566 Number of acl helper processes to keep ahead of traffic
567 loads. Squid will spawn this many at once whenever load
568 rises above the capabilities of existing processes.
569 Up to the value of children-max. (default 1)
570 concurrency=n concurrency level per process. Only used with helpers
571 capable of processing more than one query at a time.
572 cache=n limit the result cache size, default is unbounded.
573 grace=n Percentage remaining of TTL where a refresh of a
574 cached entry should be initiated without needing to
575 wait for a new reply. (default is for no grace period)
576 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
577 ipv4 / ipv6 IP protocol used to communicate with this helper.
578 The default is to auto-detect IPv6 and use it when available.
580 FORMAT specifications
582 %LOGIN Authenticated user login name
583 %EXT_USER Username from previous external acl
584 %EXT_LOG Log details from previous external acl
585 %EXT_TAG Tag from previous external acl
586 %IDENT Ident user name
588 %SRCPORT Client source port
591 %PROTO Requested protocol
593 %PATH Requested URL path
594 %METHOD Request method
595 %MYADDR Squid interface address
596 %MYPORT Squid http_port number
597 %PATH Requested URL-path (including query-string if any)
598 %USER_CERT SSL User certificate in PEM format
599 %USER_CERTCHAIN SSL User certificate chain in PEM format
600 %USER_CERT_xx SSL User certificate subject attribute xx
601 %USER_CA_xx SSL User certificate issuer attribute xx
603 %>{Header} HTTP request header "Header"
605 HTTP request header "Hdr" list member "member"
607 HTTP request header list member using ; as
608 list separator. ; can be any non-alphanumeric
611 %<{Header} HTTP reply header "Header"
613 HTTP reply header "Hdr" list member "member"
615 HTTP reply header list member using ; as
616 list separator. ; can be any non-alphanumeric
619 %% The percent sign. Useful for helpers which need
620 an unchanging input format.
622 In addition to the above, any string specified in the referencing
623 acl will also be included in the helper request line, after the
624 specified formats (see the "acl external" directive)
626 The helper receives lines per the above format specification,
627 and returns lines starting with OK or ERR indicating the validity
628 of the request and optionally followed by additional keywords with
631 General result syntax:
633 OK/ERR keyword=value ...
637 user= The users name (login)
638 password= The users password (for login= cache_peer option)
639 message= Message describing the reason. Available as %o
641 tag= Apply a tag to a request (for both ERR and OK results)
642 Only sets a tag, does not alter existing tags.
643 log= String to be logged in access.log. Available as
644 %ea in logformat specifications
646 If protocol=3.0 (the default) then URL escaping is used to protect
647 each value in both requests and responses.
649 If using protocol=2.5 then all values need to be enclosed in quotes
650 if they may contain whitespace, or the whitespace escaped using \.
651 And quotes or \ characters within the keyword value must be \ escaped.
653 When using the concurrency= option the protocol is changed by
654 introducing a query channel tag infront of the request/response.
655 The query channel tag is a number between 0 and concurrency-1.
662 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
663 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
664 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
665 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
666 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
669 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
670 DEFAULT: localhost src 127.0.0.1/32 ::1
671 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
672 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
674 Defining an Access List
676 Every access list definition must begin with an aclname and acltype,
677 followed by either type-specific arguments or a quoted filename that
680 acl aclname acltype argument ...
681 acl aclname acltype "file" ...
683 When using "file", the file should contain one item per line.
685 By default, regular expressions are CASE-SENSITIVE.
686 To make them case-insensitive, use the -i option. To return case-sensitive
687 use the +i option between patterns, or make a new ACL line without -i.
689 Some acl types require suspending the current request in order
690 to access some external data source.
691 Those which do are marked with the tag [slow], those which
692 don't are marked as [fast].
693 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
694 for further information
696 ***** ACL TYPES AVAILABLE *****
698 acl aclname src ip-address/mask ... # clients IP address [fast]
699 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
700 acl aclname dst ip-address/mask ... # URL host's IP address [slow]
701 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
703 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
704 # The arp ACL requires the special configure option --enable-arp-acl.
705 # Furthermore, the ARP ACL code is not portable to all operating systems.
706 # It works on Linux, Solaris, Windows, FreeBSD, and some
707 # other *BSD variants.
710 # NOTE: Squid can only determine the MAC address for clients that are on
711 # the same subnet. If the client is on a different subnet,
712 # then Squid cannot find out its MAC address.
714 acl aclname srcdomain .foo.com ...
715 # reverse lookup, from client IP [slow]
716 acl aclname dstdomain .foo.com ...
717 # Destination server from URL [fast]
718 acl aclname srcdom_regex [-i] \.foo\.com ...
719 # regex matching client name [slow]
720 acl aclname dstdom_regex [-i] \.foo\.com ...
721 # regex matching server [fast]
723 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
724 # based URL is used and no match is found. The name "none" is used
725 # if the reverse lookup fails.
727 acl aclname src_as number ...
728 acl aclname dst_as number ...
730 # Except for access control, AS numbers can be used for
731 # routing of requests to specific caches. Here's an
732 # example for routing all requests for AS#1241 and only
733 # those to mycache.mydomain.net:
734 # acl asexample dst_as 1241
735 # cache_peer_access mycache.mydomain.net allow asexample
736 # cache_peer_access mycache_mydomain.net deny all
738 acl aclname peername myPeer ...
740 # match against a named cache_peer entry
741 # set unique name= on cache_peer lines for reliable use.
743 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
753 # h1:m1 must be less than h2:m2
755 acl aclname url_regex [-i] ^http:// ...
756 # regex matching on whole URL [fast]
757 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
758 # regex matching on URL login field
759 acl aclname urlpath_regex [-i] \.gif$ ...
760 # regex matching on URL path [fast]
762 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
764 acl aclname localport 3128 ... # TCP port the client connected to [fast]
765 # NP: for interception mode this is usually '80'
767 acl aclname myportname 3128 ... # http(s)_port name [fast]
769 acl aclname proto HTTP FTP ... # request protocol [fast]
771 acl aclname method GET POST ... # HTTP request method [fast]
773 acl aclname http_status 200 301 500- 400-403 ...
774 # status code in reply [fast]
776 acl aclname browser [-i] regexp ...
777 # pattern match on User-Agent header (see also req_header below) [fast]
779 acl aclname referer_regex [-i] regexp ...
780 # pattern match on Referer header [fast]
781 # Referer is highly unreliable, so use with care
783 acl aclname ident username ...
784 acl aclname ident_regex [-i] pattern ...
785 # string match on ident output [slow]
786 # use REQUIRED to accept any non-null ident.
788 acl aclname proxy_auth [-i] username ...
789 acl aclname proxy_auth_regex [-i] pattern ...
790 # perform http authentication challenge to the client and match against
791 # supplied credentials [slow]
793 # takes a list of allowed usernames.
794 # use REQUIRED to accept any valid username.
796 # Will use proxy authentication in forward-proxy scenarios, and plain
797 # http authenticaiton in reverse-proxy scenarios
799 # NOTE: when a Proxy-Authentication header is sent but it is not
800 # needed during ACL checking the username is NOT logged
803 # NOTE: proxy_auth requires a EXTERNAL authentication program
804 # to check username/password combinations (see
805 # auth_param directive).
807 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
808 # as the browser needs to be configured for using a proxy in order
809 # to respond to proxy authentication.
811 acl aclname snmp_community string ...
812 # A community string to limit access to your SNMP Agent [fast]
815 # acl snmppublic snmp_community public
817 acl aclname maxconn number
818 # This will be matched when the client's IP address has
819 # more than <number> TCP connections established. [fast]
820 # NOTE: This only measures direct TCP links so X-Forwarded-For
821 # indirect clients are not counted.
823 acl aclname max_user_ip [-s] number
824 # This will be matched when the user attempts to log in from more
825 # than <number> different ip addresses. The authenticate_ip_ttl
826 # parameter controls the timeout on the ip entries. [fast]
827 # If -s is specified the limit is strict, denying browsing
828 # from any further IP addresses until the ttl has expired. Without
829 # -s Squid will just annoy the user by "randomly" denying requests.
830 # (the counter is reset each time the limit is reached and a
832 # NOTE: in acceleration mode or where there is mesh of child proxies,
833 # clients may appear to come from multiple addresses if they are
834 # going through proxy farms, so a limit of 1 may cause user problems.
836 acl aclname random probability
837 # Pseudo-randomly match requests. Based on the probability given.
838 # Probability may be written as a decimal (0.333), fraction (1/3)
839 # or ratio of matches:non-matches (3:5).
841 acl aclname req_mime_type [-i] mime-type ...
842 # regex match against the mime type of the request generated
843 # by the client. Can be used to detect file upload or some
844 # types HTTP tunneling requests [fast]
845 # NOTE: This does NOT match the reply. You cannot use this
846 # to match the returned file type.
848 acl aclname req_header header-name [-i] any\.regex\.here
849 # regex match against any of the known request headers. May be
850 # thought of as a superset of "browser", "referer" and "mime-type"
853 acl aclname rep_mime_type [-i] mime-type ...
854 # regex match against the mime type of the reply received by
855 # squid. Can be used to detect file download or some
856 # types HTTP tunneling requests. [fast]
857 # NOTE: This has no effect in http_access rules. It only has
858 # effect in rules that affect the reply data stream such as
861 acl aclname rep_header header-name [-i] any\.regex\.here
862 # regex match against any of the known reply headers. May be
863 # thought of as a superset of "browser", "referer" and "mime-type"
866 acl aclname external class_name [arguments...]
867 # external ACL lookup via a helper class defined by the
868 # external_acl_type directive [slow]
870 acl aclname user_cert attribute values...
871 # match against attributes in a user SSL certificate
872 # attribute is one of DN/C/O/CN/L/ST [fast]
874 acl aclname ca_cert attribute values...
875 # match against attributes a users issuing CA SSL certificate
876 # attribute is one of DN/C/O/CN/L/ST [fast]
878 acl aclname ext_user username ...
879 acl aclname ext_user_regex [-i] pattern ...
880 # string match on username returned by external acl helper [slow]
881 # use REQUIRED to accept any non-null user name.
883 acl aclname tag tagvalue ...
884 # string match on tag returned by external acl helper [slow]
886 acl aclname hier_code codename ...
887 # string match against squid hierarchy code(s); [fast]
888 # e.g., DIRECT, PARENT_HIT, NONE, etc.
890 # NOTE: This has no effect in http_access rules. It only has
891 # effect in rules that affect the reply data stream such as
895 acl aclname ssl_error errorname
896 # match against SSL certificate validation error [fast]
898 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
901 # The following can be used as shortcuts for certificate properties:
902 # [ssl::]certHasExpired: the "not after" field is in the past
903 # [ssl::]certNotYetValid: the "not before" field is in the future
904 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
905 # [ssl::]certSelfSigned: The certificate is self signed.
906 # [ssl::]certDomainMismatch: The certificate CN domain does not
907 # match the name the name of the host we are connecting to.
909 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
910 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
911 # predefined ACLs, just like the 'all' ACL.
913 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
914 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
916 acl aclname server_ssl_cert_fingerprint [-sha1] fingerprint
917 # match against server SSL certificate fingerprint [fast]
919 # The fingerprint is the digest of the DER encoded version
920 # of the whole certificate. The user should use the form: XX:XX:...
921 # Optional argument specifies the digest algorithm to use.
922 # The SHA1 digest algorithm is the default and is currently
923 # the only algorithm supported (-sha1).
927 acl macaddress arp 09:00:2b:23:45:67
928 acl myexample dst_as 1241
929 acl password proxy_auth REQUIRED
930 acl fileupload req_mime_type -i ^multipart/form-data$
931 acl javascript rep_mime_type -i ^application/x-javascript$
935 # Recommended minimum configuration:
938 # Example rule allowing access from your local networks.
939 # Adapt to list your (internal) IP networks from where browsing
941 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
942 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
943 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
944 acl localnet src fc00::/7 # RFC 4193 local private network range
945 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
947 acl SSL_ports port 443
948 acl Safe_ports port 80 # http
949 acl Safe_ports port 21 # ftp
950 acl Safe_ports port 443 # https
951 acl Safe_ports port 70 # gopher
952 acl Safe_ports port 210 # wais
953 acl Safe_ports port 1025-65535 # unregistered ports
954 acl Safe_ports port 280 # http-mgmt
955 acl Safe_ports port 488 # gss-http
956 acl Safe_ports port 591 # filemaker
957 acl Safe_ports port 777 # multiling http
958 acl CONNECT method CONNECT
962 NAME: follow_x_forwarded_for
964 IFDEF: FOLLOW_X_FORWARDED_FOR
965 LOC: Config.accessList.followXFF
966 DEFAULT_IF_NONE: deny all
968 Allowing or Denying the X-Forwarded-For header to be followed to
969 find the original source of a request.
971 Requests may pass through a chain of several other proxies
972 before reaching us. The X-Forwarded-For header will contain a
973 comma-separated list of the IP addresses in the chain, with the
974 rightmost address being the most recent.
976 If a request reaches us from a source that is allowed by this
977 configuration item, then we consult the X-Forwarded-For header
978 to see where that host received the request from. If the
979 X-Forwarded-For header contains multiple addresses, we continue
980 backtracking until we reach an address for which we are not allowed
981 to follow the X-Forwarded-For header, or until we reach the first
982 address in the list. For the purpose of ACL used in the
983 follow_x_forwarded_for directive the src ACL type always matches
984 the address we are testing and srcdomain matches its rDNS.
986 The end result of this process is an IP address that we will
987 refer to as the indirect client address. This address may
988 be treated as the client address for access control, ICAP, delay
989 pools and logging, depending on the acl_uses_indirect_client,
990 icap_uses_indirect_client, delay_pool_uses_indirect_client,
991 log_uses_indirect_client and tproxy_uses_indirect_client options.
993 This clause only supports fast acl types.
994 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
996 SECURITY CONSIDERATIONS:
998 Any host for which we follow the X-Forwarded-For header
999 can place incorrect information in the header, and Squid
1000 will use the incorrect information as if it were the
1001 source address of the request. This may enable remote
1002 hosts to bypass any access control restrictions that are
1003 based on the client's source addresses.
1007 acl localhost src 127.0.0.1
1008 acl my_other_proxy srcdomain .proxy.example.com
1009 follow_x_forwarded_for allow localhost
1010 follow_x_forwarded_for allow my_other_proxy
1013 NAME: acl_uses_indirect_client
1016 IFDEF: FOLLOW_X_FORWARDED_FOR
1018 LOC: Config.onoff.acl_uses_indirect_client
1020 Controls whether the indirect client address
1021 (see follow_x_forwarded_for) is used instead of the
1022 direct client address in acl matching.
1024 NOTE: maxconn ACL considers direct TCP links and indirect
1025 clients will always have zero. So no match.
1028 NAME: delay_pool_uses_indirect_client
1031 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1033 LOC: Config.onoff.delay_pool_uses_indirect_client
1035 Controls whether the indirect client address
1036 (see follow_x_forwarded_for) is used instead of the
1037 direct client address in delay pools.
1040 NAME: log_uses_indirect_client
1043 IFDEF: FOLLOW_X_FORWARDED_FOR
1045 LOC: Config.onoff.log_uses_indirect_client
1047 Controls whether the indirect client address
1048 (see follow_x_forwarded_for) is used instead of the
1049 direct client address in the access log.
1052 NAME: tproxy_uses_indirect_client
1055 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1057 LOC: Config.onoff.tproxy_uses_indirect_client
1059 Controls whether the indirect client address
1060 (see follow_x_forwarded_for) is used instead of the
1061 direct client address when spoofing the outgoing client.
1063 This has no effect on requests arriving in non-tproxy
1066 SECURITY WARNING: Usage of this option is dangerous
1067 and should not be used trivially. Correct configuration
1068 of follow_x_forewarded_for with a limited set of trusted
1069 sources is required to prevent abuse of your proxy.
1074 LOC: Config.accessList.http
1075 DEFAULT_IF_NONE: deny all
1077 Allowing or Denying access based on defined access lists
1079 Access to the HTTP port:
1080 http_access allow|deny [!]aclname ...
1082 NOTE on default values:
1084 If there are no "access" lines present, the default is to deny
1087 If none of the "access" lines cause a match, the default is the
1088 opposite of the last line in the list. If the last line was
1089 deny, the default is allow. Conversely, if the last line
1090 is allow, the default will be deny. For these reasons, it is a
1091 good idea to have an "deny all" entry at the end of your access
1092 lists to avoid potential confusion.
1094 This clause supports both fast and slow acl types.
1095 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1100 # Recommended minimum Access Permission configuration:
1102 # Only allow cachemgr access from localhost
1103 http_access allow localhost manager
1104 http_access deny manager
1106 # Deny requests to certain unsafe ports
1107 http_access deny !Safe_ports
1109 # Deny CONNECT to other than secure SSL ports
1110 http_access deny CONNECT !SSL_ports
1112 # We strongly recommend the following be uncommented to protect innocent
1113 # web applications running on the proxy server who think the only
1114 # one who can access services on "localhost" is a local user
1115 #http_access deny to_localhost
1118 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1121 # Example rule allowing access from your local networks.
1122 # Adapt localnet in the ACL section to list your (internal) IP networks
1123 # from where browsing should be allowed
1124 http_access allow localnet
1125 http_access allow localhost
1127 # And finally deny all other access to this proxy
1128 http_access deny all
1132 NAME: adapted_http_access http_access2
1134 LOC: Config.accessList.adapted_http
1137 Allowing or Denying access based on defined access lists
1139 Essentially identical to http_access, but runs after redirectors
1140 and ICAP/eCAP adaptation. Allowing access control based on their
1143 If not set then only http_access is used.
1146 NAME: http_reply_access
1148 LOC: Config.accessList.reply
1151 Allow replies to client requests. This is complementary to http_access.
1153 http_reply_access allow|deny [!] aclname ...
1155 NOTE: if there are no access lines present, the default is to allow
1158 If none of the access lines cause a match the opposite of the
1159 last line will apply. Thus it is good practice to end the rules
1160 with an "allow all" or "deny all" entry.
1162 This clause supports both fast and slow acl types.
1163 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1168 LOC: Config.accessList.icp
1169 DEFAULT_IF_NONE: deny all
1171 Allowing or Denying access to the ICP port based on defined
1174 icp_access allow|deny [!]aclname ...
1176 See http_access for details
1178 This clause only supports fast acl types.
1179 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1181 # Allow ICP queries from local networks only
1182 #icp_access allow localnet
1183 #icp_access deny all
1189 LOC: Config.accessList.htcp
1190 DEFAULT_IF_NONE: deny all
1192 Allowing or Denying access to the HTCP port based on defined
1195 htcp_access allow|deny [!]aclname ...
1197 See http_access for details
1199 NOTE: The default if no htcp_access lines are present is to
1200 deny all traffic. This default may cause problems with peers
1201 using the htcp option.
1203 This clause only supports fast acl types.
1204 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1206 # Allow HTCP queries from local networks only
1207 #htcp_access allow localnet
1208 #htcp_access deny all
1211 NAME: htcp_clr_access
1214 LOC: Config.accessList.htcp_clr
1215 DEFAULT_IF_NONE: deny all
1217 Allowing or Denying access to purge content using HTCP based
1218 on defined access lists
1220 htcp_clr_access allow|deny [!]aclname ...
1222 See http_access for details
1224 This clause only supports fast acl types.
1225 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1227 # Allow HTCP CLR requests from trusted peers
1228 acl htcp_clr_peer src 172.16.1.2
1229 htcp_clr_access allow htcp_clr_peer
1234 LOC: Config.accessList.miss
1237 Determins whether network access is permitted when satisfying a request.
1240 to force your neighbors to use you as a sibling instead of
1243 acl localclients src 172.16.0.0/16
1244 miss_access allow localclients
1245 miss_access deny !localclients
1247 This means only your local clients are allowed to fetch relayed/MISS
1248 replies from the network and all other clients can only fetch cached
1252 The default for this setting allows all clients who passed the
1253 http_access rules to relay via this proxy.
1255 This clause only supports fast acl types.
1256 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1259 NAME: ident_lookup_access
1262 DEFAULT_IF_NONE: deny all
1263 LOC: Ident::TheConfig.identLookup
1265 A list of ACL elements which, if matched, cause an ident
1266 (RFC 931) lookup to be performed for this request. For
1267 example, you might choose to always perform ident lookups
1268 for your main multi-user Unix boxes, but not for your Macs
1269 and PCs. By default, ident lookups are not performed for
1272 To enable ident lookups for specific client addresses, you
1273 can follow this example:
1275 acl ident_aware_hosts src 198.168.1.0/24
1276 ident_lookup_access allow ident_aware_hosts
1277 ident_lookup_access deny all
1279 Only src type ACL checks are fully supported. A srcdomain
1280 ACL might work at times, but it will not always provide
1283 This clause only supports fast acl types.
1284 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1287 NAME: reply_body_max_size
1288 COMMENT: size [acl acl...]
1291 LOC: Config.ReplyBodySize
1293 This option specifies the maximum size of a reply body. It can be
1294 used to prevent users from downloading very large files, such as
1295 MP3's and movies. When the reply headers are received, the
1296 reply_body_max_size lines are processed, and the first line where
1297 all (if any) listed ACLs are true is used as the maximum body size
1300 This size is checked twice. First when we get the reply headers,
1301 we check the content-length value. If the content length value exists
1302 and is larger than the allowed size, the request is denied and the
1303 user receives an error message that says "the request or reply
1304 is too large." If there is no content-length, and the reply
1305 size exceeds this limit, the client's connection is just closed
1306 and they will receive a partial reply.
1308 WARNING: downstream caches probably can not detect a partial reply
1309 if there is no content-length header, so they will cache
1310 partial responses and give them out as hits. You should NOT
1311 use this option if you have downstream caches.
1313 WARNING: A maximum size smaller than the size of squid's error messages
1314 will cause an infinite loop and crash squid. Ensure that the smallest
1315 non-zero value you use is greater that the maximum header size plus
1316 the size of your largest error page.
1318 If you set this parameter none (the default), there will be
1321 Configuration Format is:
1322 reply_body_max_size SIZE UNITS [acl ...]
1324 reply_body_max_size 10 MB
1330 -----------------------------------------------------------------------------
1333 NAME: http_port ascii_port
1336 LOC: Config.Sockaddr.http
1338 Usage: port [mode] [options]
1339 hostname:port [mode] [options]
1340 1.2.3.4:port [mode] [options]
1342 The socket addresses where Squid will listen for HTTP client
1343 requests. You may specify multiple socket addresses.
1344 There are three forms: port alone, hostname with port, and
1345 IP address with port. If you specify a hostname or IP
1346 address, Squid binds the socket to that specific
1347 address. Most likely, you do not need to bind to a specific
1348 address, so you can use the port number alone.
1350 If you are running Squid in accelerator mode, you
1351 probably want to listen on port 80 also, or instead.
1353 The -a command line option may be used to specify additional
1354 port(s) where Squid listens for proxy request. Such ports will
1355 be plain proxy ports with no options.
1357 You may specify multiple socket addresses on multiple lines.
1361 intercept Support for IP-Layer interception of
1362 outgoing requests without browser settings.
1363 NP: disables authentication and IPv6 on the port.
1365 tproxy Support Linux TPROXY for spoofing outgoing
1366 connections using the client IP address.
1367 NP: disables authentication and maybe IPv6 on the port.
1369 accel Accelerator / reverse proxy mode
1371 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1372 establish secure connection with the client and with
1373 the server, decrypt HTTPS messages as they pass through
1374 Squid, and treat them as unencrypted HTTP messages,
1375 becoming the man-in-the-middle.
1377 The ssl_bump option is required to fully enable
1378 bumping of CONNECT requests.
1380 Omitting the mode flag causes default forward proxy mode to be used.
1383 Accelerator Mode Options:
1385 defaultsite=domainname
1386 What to use for the Host: header if it is not present
1387 in a request. Determines what site (not origin server)
1388 accelerators should consider the default.
1390 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1392 protocol= Protocol to reconstruct accelerated requests with.
1393 Defaults to http for http_port and https for
1396 vport Virtual host port support. Using the http_port number
1397 instead of the port passed on Host: headers.
1399 vport=NN Virtual host port support. Using the specified port
1400 number instead of the port passed on Host: headers.
1403 Act as if this Squid is the origin server.
1404 This currently means generate new Date: and Expires:
1405 headers on HIT instead of adding Age:.
1407 ignore-cc Ignore request Cache-Control headers.
1409 WARNING: This option violates HTTP specifications if
1410 used in non-accelerator setups.
1412 allow-direct Allow direct forwarding in accelerator mode. Normally
1413 accelerated requests are denied direct forwarding as if
1414 never_direct was used.
1416 WARNING: this option opens accelerator mode to security
1417 vulnerabilities usually only affecting in interception
1418 mode. Make sure to protect forwarding with suitable
1419 http_access rules when using this.
1422 SSL Bump Mode Options:
1423 In addition to these options ssl-bump requires TLS/SSL options.
1425 generate-host-certificates[=<on|off>]
1426 Dynamically create SSL server certificates for the
1427 destination hosts of bumped CONNECT requests.When
1428 enabled, the cert and key options are used to sign
1429 generated certificates. Otherwise generated
1430 certificate will be selfsigned.
1431 If there is a CA certificate lifetime of the generated
1432 certificate equals lifetime of the CA certificate. If
1433 generated certificate is selfsigned lifetime is three
1435 This option is enabled by default when ssl-bump is used.
1436 See the ssl-bump option above for more information.
1438 dynamic_cert_mem_cache_size=SIZE
1439 Approximate total RAM size spent on cached generated
1440 certificates. If set to zero, caching is disabled. The
1441 default value is 4MB.
1445 cert= Path to SSL certificate (PEM format).
1447 key= Path to SSL private key file (PEM format)
1448 if not specified, the certificate file is
1449 assumed to be a combined certificate and
1452 version= The version of SSL/TLS supported
1453 1 automatic (default)
1460 cipher= Colon separated list of supported ciphers.
1461 NOTE: some ciphers such as EDH ciphers depend on
1462 additional settings. If those settings are
1463 omitted the ciphers may be silently ignored
1464 by the OpenSSL library.
1466 options= Various SSL implementation options. The most important
1468 NO_SSLv2 Disallow the use of SSLv2
1469 NO_SSLv3 Disallow the use of SSLv3
1470 NO_TLSv1 Disallow the use of TLSv1.0
1471 NO_TLSv1_1 Disallow the use of TLSv1.1
1472 NO_TLSv1_2 Disallow the use of TLSv1.2
1473 SINGLE_DH_USE Always create a new key when using
1474 temporary/ephemeral DH key exchanges
1475 ALL Enable various bug workarounds
1476 suggested as "harmless" by OpenSSL
1477 Be warned that this reduces SSL/TLS
1478 strength to some attacks.
1479 See OpenSSL SSL_CTX_set_options documentation for a
1480 complete list of options.
1482 clientca= File containing the list of CAs to use when
1483 requesting a client certificate.
1485 cafile= File containing additional CA certificates to
1486 use when verifying client certificates. If unset
1487 clientca will be used.
1489 capath= Directory containing additional CA certificates
1490 and CRL lists to use when verifying client certificates.
1492 crlfile= File of additional CRL lists to use when verifying
1493 the client certificate, in addition to CRLs stored in
1494 the capath. Implies VERIFY_CRL flag below.
1496 dhparams= File containing DH parameters for temporary/ephemeral
1497 DH key exchanges. See OpenSSL documentation for details
1498 on how to create this file.
1499 WARNING: EDH ciphers will be silently disabled if this
1502 sslflags= Various flags modifying the use of SSL:
1504 Don't request client certificates
1505 immediately, but wait until acl processing
1506 requires a certificate (not yet implemented).
1508 Don't use the default CA lists built in
1511 Don't allow for session reuse. Each connection
1512 will result in a new SSL session.
1514 Verify CRL lists when accepting client
1517 Verify CRL lists for all certificates in the
1518 client certificate chain.
1520 sslcontext= SSL session ID context identifier.
1524 connection-auth[=on|off]
1525 use connection-auth=off to tell Squid to prevent
1526 forwarding Microsoft connection oriented authentication
1527 (NTLM, Negotiate and Kerberos)
1529 disable-pmtu-discovery=
1530 Control Path-MTU discovery usage:
1531 off lets OS decide on what to do (default).
1532 transparent disable PMTU discovery when transparent
1534 always disable always PMTU discovery.
1536 In many setups of transparently intercepting proxies
1537 Path-MTU discovery can not work on traffic towards the
1538 clients. This is the case when the intercepting device
1539 does not fully track connections and fails to forward
1540 ICMP must fragment messages to the cache server. If you
1541 have such setup and experience that certain clients
1542 sporadically hang or never complete requests set
1543 disable-pmtu-discovery option to 'transparent'.
1545 name= Specifies a internal name for the port. Defaults to
1546 the port specification (port or addr:port)
1548 tcpkeepalive[=idle,interval,timeout]
1549 Enable TCP keepalive probes of idle connections.
1550 In seconds; idle is the initial time before TCP starts
1551 probing the connection, interval how often to probe, and
1552 timeout the time before giving up.
1554 If you run Squid on a dual-homed machine with an internal
1555 and an external interface we recommend you to specify the
1556 internal address:port in http_port. This way Squid will only be
1557 visible on the internal address.
1561 # Squid normally listens to port 3128
1562 http_port @DEFAULT_HTTP_PORT@
1570 LOC: Config.Sockaddr.https
1572 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1574 The socket address where Squid will listen for client requests made
1575 over TLS or SSL connections. Commonly referred to as HTTPS.
1577 This is most useful for situations where you are running squid in
1578 accelerator mode and you want to do the SSL work at the accelerator level.
1580 You may specify multiple socket addresses on multiple lines,
1581 each with their own SSL certificate and/or options.
1585 accel Accelerator / reverse proxy mode
1587 intercept Support for IP-Layer interception of
1588 outgoing requests without browser settings.
1589 NP: disables authentication and IPv6 on the port.
1591 tproxy Support Linux TPROXY for spoofing outgoing
1592 connections using the client IP address.
1593 NP: disables authentication and maybe IPv6 on the port.
1595 ssl-bump For each intercepted connection allowed by ssl_bump
1596 ACLs, establish a secure connection with the client and with
1597 the server, decrypt HTTPS messages as they pass through
1598 Squid, and treat them as unencrypted HTTP messages,
1599 becoming the man-in-the-middle.
1601 An "ssl_bump server-first" match is required to
1602 fully enable bumping of intercepted SSL connections.
1604 Requires tproxy or intercept.
1606 Omitting the mode flag causes default forward proxy mode to be used.
1609 See http_port for a list of generic options
1614 cert= Path to SSL certificate (PEM format).
1616 key= Path to SSL private key file (PEM format)
1617 if not specified, the certificate file is
1618 assumed to be a combined certificate and
1621 version= The version of SSL/TLS supported
1622 1 automatic (default)
1627 cipher= Colon separated list of supported ciphers.
1629 options= Various SSL engine options. The most important
1631 NO_SSLv2 Disallow the use of SSLv2
1632 NO_SSLv3 Disallow the use of SSLv3
1633 NO_TLSv1 Disallow the use of TLSv1
1634 SINGLE_DH_USE Always create a new key when using
1635 temporary/ephemeral DH key exchanges
1636 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1637 documentation for a complete list of options.
1639 clientca= File containing the list of CAs to use when
1640 requesting a client certificate.
1642 cafile= File containing additional CA certificates to
1643 use when verifying client certificates. If unset
1644 clientca will be used.
1646 capath= Directory containing additional CA certificates
1647 and CRL lists to use when verifying client certificates.
1649 crlfile= File of additional CRL lists to use when verifying
1650 the client certificate, in addition to CRLs stored in
1651 the capath. Implies VERIFY_CRL flag below.
1653 dhparams= File containing DH parameters for temporary/ephemeral
1656 sslflags= Various flags modifying the use of SSL:
1658 Don't request client certificates
1659 immediately, but wait until acl processing
1660 requires a certificate (not yet implemented).
1662 Don't use the default CA lists built in
1665 Don't allow for session reuse. Each connection
1666 will result in a new SSL session.
1668 Verify CRL lists when accepting client
1671 Verify CRL lists for all certificates in the
1672 client certificate chain.
1674 sslcontext= SSL session ID context identifier.
1676 generate-host-certificates[=<on|off>]
1677 Dynamically create SSL server certificates for the
1678 destination hosts of bumped SSL requests.When
1679 enabled, the cert and key options are used to sign
1680 generated certificates. Otherwise generated
1681 certificate will be selfsigned.
1682 If there is CA certificate life time of generated
1683 certificate equals lifetime of CA certificate. If
1684 generated certificate is selfsigned lifetime is three
1686 This option is enabled by default when SslBump is used.
1687 See the sslBump option above for more information.
1689 dynamic_cert_mem_cache_size=SIZE
1690 Approximate total RAM size spent on cached generated
1691 certificates. If set to zero, caching is disabled. The
1692 default value is 4MB.
1694 See http_port for a list of available options.
1697 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1700 LOC: Ip::Qos::TheConfig.tosToServer
1702 Allows you to select a TOS/Diffserv value for packets outgoing
1703 on the server side, based on an ACL.
1705 tcp_outgoing_tos ds-field [!]aclname ...
1707 Example where normal_service_net uses the TOS value 0x00
1708 and good_service_net uses 0x20
1710 acl normal_service_net src 10.0.0.0/24
1711 acl good_service_net src 10.0.1.0/24
1712 tcp_outgoing_tos 0x00 normal_service_net
1713 tcp_outgoing_tos 0x20 good_service_net
1715 TOS/DSCP values really only have local significance - so you should
1716 know what you're specifying. For more information, see RFC2474,
1717 RFC2475, and RFC3260.
1719 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1720 "default" to use whatever default your host has. Note that in
1721 practice often only multiples of 4 is usable as the two rightmost bits
1722 have been redefined for use by ECN (RFC 3168 section 23.1).
1724 Processing proceeds in the order specified, and stops at first fully
1728 NAME: clientside_tos
1731 LOC: Ip::Qos::TheConfig.tosToClient
1733 Allows you to select a TOS/Diffserv value for packets being transmitted
1734 on the client-side, based on an ACL.
1736 clientside_tos ds-field [!]aclname ...
1738 Example where normal_service_net uses the TOS value 0x00
1739 and good_service_net uses 0x20
1741 acl normal_service_net src 10.0.0.0/24
1742 acl good_service_net src 10.0.1.0/24
1743 clientside_tos 0x00 normal_service_net
1744 clientside_tos 0x20 good_service_net
1746 Note: This feature is incompatible with qos_flows. Any TOS values set here
1747 will be overwritten by TOS values in qos_flows.
1750 NAME: tcp_outgoing_mark
1752 IFDEF: SO_MARK&&USE_LIBCAP
1754 LOC: Ip::Qos::TheConfig.nfmarkToServer
1756 Allows you to apply a Netfilter mark value to outgoing packets
1757 on the server side, based on an ACL.
1759 tcp_outgoing_mark mark-value [!]aclname ...
1761 Example where normal_service_net uses the mark value 0x00
1762 and good_service_net uses 0x20
1764 acl normal_service_net src 10.0.0.0/24
1765 acl good_service_net src 10.0.1.0/24
1766 tcp_outgoing_mark 0x00 normal_service_net
1767 tcp_outgoing_mark 0x20 good_service_net
1770 NAME: clientside_mark
1772 IFDEF: SO_MARK&&USE_LIBCAP
1774 LOC: Ip::Qos::TheConfig.nfmarkToClient
1776 Allows you to apply a Netfilter mark value to packets being transmitted
1777 on the client-side, based on an ACL.
1779 clientside_mark mark-value [!]aclname ...
1781 Example where normal_service_net uses the mark value 0x00
1782 and good_service_net uses 0x20
1784 acl normal_service_net src 10.0.0.0/24
1785 acl good_service_net src 10.0.1.0/24
1786 clientside_mark 0x00 normal_service_net
1787 clientside_mark 0x20 good_service_net
1789 Note: This feature is incompatible with qos_flows. Any mark values set here
1790 will be overwritten by mark values in qos_flows.
1797 LOC: Ip::Qos::TheConfig
1799 Allows you to select a TOS/DSCP value to mark outgoing
1800 connections with, based on where the reply was sourced. For
1801 platforms using netfilter, allows you to set a netfilter mark
1802 value instead of, or in addition to, a TOS value.
1804 TOS values really only have local significance - so you should
1805 know what you're specifying. For more information, see RFC2474,
1806 RFC2475, and RFC3260.
1808 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1809 in practice often only multiples of 4 is usable as the two rightmost bits
1810 have been redefined for use by ECN (RFC 3168 section 23.1).
1812 Mark values can be any unsigned 32-bit integer value.
1814 This setting is configured by setting the following values:
1816 tos|mark Whether to set TOS or netfilter mark values
1818 local-hit=0xFF Value to mark local cache hits.
1820 sibling-hit=0xFF Value to mark hits from sibling peers.
1822 parent-hit=0xFF Value to mark hits from parent peers.
1824 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
1825 over the preserve-miss feature (see below), unless
1826 mask is specified, in which case only the bits
1827 specified in the mask are written.
1829 The TOS variant of the following features are only possible on Linux
1830 and require your kernel to be patched with the TOS preserving ZPH
1831 patch, available from http://zph.bratcheda.org
1832 No patch is needed to preserve the netfilter mark, which will work
1833 with all variants of netfilter.
1835 disable-preserve-miss
1836 This option disables the preservation of the TOS or netfilter
1837 mark. By default, the existing TOS or netfilter mark value of
1838 the response coming from the remote server will be retained
1839 and masked with miss-mark.
1840 NOTE: in the case of a netfilter mark, the mark must be set on
1841 the connection (using the CONNMARK target) not on the packet
1845 Allows you to mask certain bits in the TOS or mark value
1846 received from the remote server, before copying the value to
1847 the TOS sent towards clients.
1848 Default for tos: 0xFF (TOS from server is not changed).
1849 Default for mark: 0xFFFFFFFF (mark from server is not changed).
1851 All of these features require the --enable-zph-qos compilation flag
1852 (enabled by default). Netfilter marking also requires the
1853 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
1854 libcap 2.09+ (--with-libcap).
1858 NAME: tcp_outgoing_address
1861 LOC: Config.accessList.outgoing_address
1863 Allows you to map requests to different outgoing IP addresses
1864 based on the username or source address of the user making
1867 tcp_outgoing_address ipaddr [[!]aclname] ...
1870 Forwarding clients with dedicated IPs for certain subnets.
1872 acl normal_service_net src 10.0.0.0/24
1873 acl good_service_net src 10.0.2.0/24
1875 tcp_outgoing_address 2001:db8::c001 good_service_net
1876 tcp_outgoing_address 10.1.0.2 good_service_net
1878 tcp_outgoing_address 2001:db8::beef normal_service_net
1879 tcp_outgoing_address 10.1.0.1 normal_service_net
1881 tcp_outgoing_address 2001:db8::1
1882 tcp_outgoing_address 10.1.0.3
1884 Processing proceeds in the order specified, and stops at first fully
1887 Squid will add an implicit IP version test to each line.
1888 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
1889 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
1892 NOTE: The use of this directive using client dependent ACLs is
1893 incompatible with the use of server side persistent connections. To
1894 ensure correct results it is best to set server_persistent_connections
1895 to off when using this directive in such configurations.
1897 NOTE: The use of this directive to set a local IP on outgoing TCP links
1898 is incompatible with using TPROXY to set client IP out outbound TCP links.
1899 When needing to contact peers use the no-tproxy cache_peer option and the
1900 client_dst_passthru directive re-enable normal forwarding such as this.
1904 NAME: host_verify_strict
1907 LOC: Config.onoff.hostStrictVerify
1909 Regardless of this option setting, when dealing with intercepted
1910 traffic, Squid always verifies that the destination IP address matches
1911 the Host header domain or IP (called 'authority form URL').
1913 This enforcement is performed to satisfy a MUST-level requirement in
1914 RFC 2616 section 14.23: "The Host field value MUST represent the naming
1915 authority of the origin server or gateway given by the original URL".
1918 Squid always responds with an HTTP 409 (Conflict) error
1919 page and logs a security warning if there is no match.
1921 Squid verifies that the destination IP address matches
1922 the Host header for forward-proxy and reverse-proxy traffic
1923 as well. For those traffic types, Squid also enables the
1924 following checks, comparing the corresponding Host header
1925 and Request-URI components:
1927 * The host names (domain or IP) must be identical,
1928 but valueless or missing Host header disables all checks.
1929 For the two host names to match, both must be either IP
1932 * Port numbers must be identical, but if a port is missing
1933 the scheme-default port is assumed.
1936 When set to OFF (the default):
1937 Squid allows suspicious requests to continue but logs a
1938 security warning and blocks caching of the response.
1940 * Forward-proxy traffic is not checked at all.
1942 * Reverse-proxy traffic is not checked at all.
1944 * Intercepted traffic which passes verification is handled
1945 according to client_dst_passthru.
1947 * Intercepted requests which fail verification are sent
1948 to the client original destination instead of DIRECT.
1949 This overrides 'client_dst_passthru off'.
1951 For now suspicious intercepted CONNECT requests are always
1952 responded to with an HTTP 409 (Conflict) error page.
1957 As described in CVE-2009-0801 when the Host: header alone is used
1958 to determine the destination of a request it becomes trivial for
1959 malicious scripts on remote websites to bypass browser same-origin
1960 security policy and sandboxing protections.
1962 The cause of this is that such applets are allowed to perform their
1963 own HTTP stack, in which case the same-origin policy of the browser
1964 sandbox only verifies that the applet tries to contact the same IP
1965 as from where it was loaded at the IP level. The Host: header may
1966 be different from the connected IP and approved origin.
1970 NAME: client_dst_passthru
1973 LOC: Config.onoff.client_dst_passthru
1975 With NAT or TPROXY intercepted traffic Squid may pass the request
1976 directly to the original client destination IP or seek a faster
1977 source using the HTTP Host header.
1979 Using Host to locate alternative servers can provide faster
1980 connectivity with a range of failure recovery options.
1981 But can also lead to connectivity trouble when the client and
1982 server are attempting stateful interactions unaware of the proxy.
1984 This option (on by default) prevents alternative DNS entries being
1985 located to send intercepted traffic DIRECT to an origin server.
1986 The clients original destination IP and port will be used instead.
1988 Regardless of this option setting, when dealing with intercepted
1989 traffic Squid will verify the Host: header and any traffic which
1990 fails Host verification will be treated as if this option were ON.
1992 see host_verify_strict for details on the verification process.
1997 -----------------------------------------------------------------------------
2000 NAME: ssl_unclean_shutdown
2004 LOC: Config.SSL.unclean_shutdown
2006 Some browsers (especially MSIE) bugs out on SSL shutdown
2013 LOC: Config.SSL.ssl_engine
2016 The OpenSSL engine to use. You will need to set this if you
2017 would like to use hardware SSL acceleration for example.
2020 NAME: sslproxy_client_certificate
2023 LOC: Config.ssl_client.cert
2026 Client SSL Certificate to use when proxying https:// URLs
2029 NAME: sslproxy_client_key
2032 LOC: Config.ssl_client.key
2035 Client SSL Key to use when proxying https:// URLs
2038 NAME: sslproxy_version
2041 LOC: Config.ssl_client.version
2044 SSL version level to use when proxying https:// URLs
2046 The versions of SSL/TLS supported:
2048 1 automatic (default)
2056 NAME: sslproxy_options
2059 LOC: Config.ssl_client.options
2062 SSL implementation options to use when proxying https:// URLs
2064 The most important being:
2066 NO_SSLv2 Disallow the use of SSLv2
2067 NO_SSLv3 Disallow the use of SSLv3
2068 NO_TLSv1 Disallow the use of TLSv1.0
2069 NO_TLSv1_1 Disallow the use of TLSv1.1
2070 NO_TLSv1_2 Disallow the use of TLSv1.2
2072 Always create a new key when using temporary/ephemeral
2075 Disable use of RFC5077 session tickets. Some servers
2076 may have problems understanding the TLS extension due
2077 to ambiguous specification in RFC4507.
2078 ALL Enable various bug workarounds suggested as "harmless"
2079 by OpenSSL. Be warned that this may reduce SSL/TLS
2080 strength to some attacks.
2082 See the OpenSSL SSL_CTX_set_options documentation for a
2083 complete list of possible options.
2086 NAME: sslproxy_cipher
2089 LOC: Config.ssl_client.cipher
2092 SSL cipher list to use when proxying https:// URLs
2094 Colon separated list of supported ciphers.
2097 NAME: sslproxy_cafile
2100 LOC: Config.ssl_client.cafile
2103 file containing CA certificates to use when verifying server
2104 certificates while proxying https:// URLs
2107 NAME: sslproxy_capath
2110 LOC: Config.ssl_client.capath
2113 directory containing CA certificates to use when verifying
2114 server certificates while proxying https:// URLs
2119 TYPE: sslproxy_ssl_bump
2120 LOC: Config.accessList.ssl_bump
2123 This option is consulted when a CONNECT request is received on
2124 an http_port (or a new connection is intercepted at an
2125 https_port), provided that port was configured with an ssl-bump
2126 flag. The subsequent data on the connection is either treated as
2127 HTTPS and decrypted OR tunneled at TCP level without decryption,
2128 depending on the first bumping "mode" which ACLs match.
2130 ssl_bump <mode> [!]acl ...
2132 The following bumping modes are supported:
2135 Allow bumping of the connection. Establish a secure connection
2136 with the client first, then connect to the server. This old mode
2137 does not allow Squid to mimic server SSL certificate and does
2138 not work with intercepted SSL connections.
2141 Allow bumping of the connection. Establish a secure connection
2142 with the server first, then establish a secure connection with
2143 the client, using a mimicked server certificate. Works with both
2144 CONNECT requests and intercepted SSL connections.
2147 Become a TCP tunnel without decoding the connection.
2148 Works with both CONNECT requests and intercepted SSL
2149 connections. This is the default behavior when no
2150 ssl_bump option is given or no ssl_bump ACLs match.
2152 By default, no connections are bumped.
2154 The first matching ssl_bump option wins. If no ACLs match, the
2155 connection is not bumped. Unlike most allow/deny ACL lists, ssl_bump
2156 does not have an implicit "negate the last given option" rule. You
2157 must make that rule explicit if you convert old ssl_bump allow/deny
2158 rules that rely on such an implicit rule.
2160 This clause supports both fast and slow acl types.
2161 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2163 See also: http_port ssl-bump, https_port ssl-bump
2166 # Example: Bump all requests except those originating from
2167 # localhost and those going to example.com.
2169 acl broken_sites dstdomain .example.com
2170 ssl_bump none localhost
2171 ssl_bump none broken_sites
2172 ssl_bump server-first all
2175 NAME: sslproxy_flags
2178 LOC: Config.ssl_client.flags
2181 Various flags modifying the use of SSL while proxying https:// URLs:
2182 DONT_VERIFY_PEER Accept certificates that fail verification.
2183 For refined control, see sslproxy_cert_error.
2184 NO_DEFAULT_CA Don't use the default CA list built in
2188 NAME: sslproxy_cert_error
2191 LOC: Config.ssl_client.cert_error
2194 Use this ACL to bypass server certificate validation errors.
2196 For example, the following lines will bypass all validation errors
2197 when talking to servers for example.com. All other
2198 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2200 acl BrokenButTrustedServers dstdomain example.com
2201 sslproxy_cert_error allow BrokenButTrustedServers
2202 sslproxy_cert_error deny all
2204 This clause only supports fast acl types.
2205 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2206 Using slow acl types may result in server crashes
2208 Without this option, all server certificate validation errors
2209 terminate the transaction. Bypassing validation errors is dangerous
2210 because an error usually implies that the server cannot be trusted and
2211 the connection may be insecure.
2213 See also: sslproxy_flags and DONT_VERIFY_PEER.
2215 Default setting: sslproxy_cert_error deny all
2218 NAME: sslproxy_cert_sign
2221 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2222 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2223 POSTSCRIPTUM: signTrusted all
2224 TYPE: sslproxy_cert_sign
2225 LOC: Config.ssl_client.cert_sign
2228 sslproxy_cert_sign <signing algorithm> acl ...
2230 The following certificate signing algorithms are supported:
2232 Sign using the configured CA certificate which is usually
2233 placed in and trusted by end-user browsers. This is the
2234 default for trusted origin server certificates.
2236 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2237 This is the default for untrusted origin server certificates
2238 that are not self-signed (see ssl::certUntrusted).
2240 Sign using a self-signed certificate with the right CN to
2241 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2242 browser. This is the default for self-signed origin server
2243 certificates (see ssl::certSelfSigned).
2245 This clause only supports fast acl types.
2247 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2248 signing algorithm to generate the certificate and ignores all
2249 subsequent sslproxy_cert_sign options (the first match wins). If no
2250 acl(s) match, the default signing algorithm is determined by errors
2251 detected when obtaining and validating the origin server certificate.
2253 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2254 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2255 CONNECT request that carries a domain name. In all other cases (CONNECT
2256 to an IP address or an intercepted SSL connection), Squid cannot detect
2257 the domain mismatch at certificate generation time when
2258 bump-server-first is used.
2261 NAME: sslproxy_cert_adapt
2264 TYPE: sslproxy_cert_adapt
2265 LOC: Config.ssl_client.cert_adapt
2268 sslproxy_cert_adapt <adaptation algorithm> acl ...
2270 The following certificate adaptation algorithms are supported:
2272 Sets the "Not After" property to the "Not After" property of
2273 the CA certificate used to sign generated certificates.
2275 Sets the "Not Before" property to the "Not Before" property of
2276 the CA certificate used to sign generated certificates.
2277 setCommonName or setCommonName{CN}
2278 Sets Subject.CN property to the host name specified as a
2279 CN parameter or, if no explicit CN parameter was specified,
2280 extracted from the CONNECT request. It is a misconfiguration
2281 to use setCommonName without an explicit parameter for
2282 intercepted or tproxied SSL connections.
2284 This clause only supports fast acl types.
2286 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2287 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2288 corresponding adaptation algorithm to generate the certificate and
2289 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2290 group (i.e., the first match wins within each algorithm group). If no
2291 acl(s) match, the default mimicking action takes place.
2293 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2294 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2295 CONNECT request that carries a domain name. In all other cases (CONNECT
2296 to an IP address or an intercepted SSL connection), Squid cannot detect
2297 the domain mismatch at certificate generation time when
2298 bump-server-first is used.
2301 NAME: sslpassword_program
2304 LOC: Config.Program.ssl_password
2307 Specify a program used for entering SSL key passphrases
2308 when using encrypted SSL certificate keys. If not specified
2309 keys must either be unencrypted, or Squid started with the -N
2310 option to allow it to query interactively for the passphrase.
2312 The key file name is given as argument to the program allowing
2313 selection of the right password if you have multiple encrypted
2318 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2319 -----------------------------------------------------------------------------
2322 NAME: sslcrtd_program
2325 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2326 LOC: Ssl::TheConfig.ssl_crtd
2328 Specify the location and options of the executable for ssl_crtd process.
2329 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2330 For more information use:
2331 @DEFAULT_SSL_CRTD@ -h
2334 NAME: sslcrtd_children
2335 TYPE: HelperChildConfig
2337 DEFAULT: 32 startup=5 idle=1
2338 LOC: Ssl::TheConfig.ssl_crtdChildren
2340 The maximum number of processes spawn to service ssl server.
2341 The maximum this may be safely set to is 32.
2343 The startup= and idle= options allow some measure of skew in your
2348 Sets the minimum number of processes to spawn when Squid
2349 starts or reconfigures. When set to zero the first request will
2350 cause spawning of the first child process to handle it.
2352 Starting too few children temporary slows Squid under load while it
2353 tries to spawn enough additional processes to cope with traffic.
2357 Sets a minimum of how many processes Squid is to try and keep available
2358 at all times. When traffic begins to rise above what the existing
2359 processes can handle this many more will be spawned up to the maximum
2360 configured. A minimum setting of 1 is required.
2362 You must have at least one ssl_crtd process.
2365 NAME: sslcrtvalidator_program
2369 LOC: Ssl::TheConfig.ssl_crt_validator
2371 Specify the location and options of the executable for ssl_crt_validator
2375 NAME: sslcrtvalidator_children
2376 TYPE: HelperChildConfig
2378 DEFAULT: 32 startup=5 idle=1 concurrency=1
2379 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2381 The maximum number of processes spawn to service ssl server.
2382 The maximum this may be safely set to is 32.
2384 The startup= and idle= options allow some measure of skew in your
2389 Sets the minimum number of processes to spawn when Squid
2390 starts or reconfigures. When set to zero the first request will
2391 cause spawning of the first child process to handle it.
2393 Starting too few children temporary slows Squid under load while it
2394 tries to spawn enough additional processes to cope with traffic.
2398 Sets a minimum of how many processes Squid is to try and keep available
2399 at all times. When traffic begins to rise above what the existing
2400 processes can handle this many more will be spawned up to the maximum
2401 configured. A minimum setting of 1 is required.
2405 The number of requests each certificate validator helper can handle in
2406 parallel. Defaults to 0 which indicates the certficate validator
2407 is a old-style single threaded redirector.
2409 When this directive is set to a value >= 1 then the protocol
2410 used to communicate with the helper is modified to include
2411 a request ID in front of the request/response. The request
2412 ID from the request must be echoed back with the response
2415 You must have at least one ssl_crt_validator process.
2419 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2420 -----------------------------------------------------------------------------
2428 To specify other caches in a hierarchy, use the format:
2430 cache_peer hostname type http-port icp-port [options]
2435 # hostname type port port options
2436 # -------------------- -------- ----- ----- -----------
2437 cache_peer parent.foo.net parent 3128 3130 default
2438 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2439 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2440 cache_peer example.com parent 80 0 default
2441 cache_peer cdn.example.com sibling 3128 0
2443 type: either 'parent', 'sibling', or 'multicast'.
2445 proxy-port: The port number where the peer accept HTTP requests.
2446 For other Squid proxies this is usually 3128
2447 For web servers this is usually 80
2449 icp-port: Used for querying neighbor caches about objects.
2450 Set to 0 if the peer does not support ICP or HTCP.
2451 See ICP and HTCP options below for additional details.
2454 ==== ICP OPTIONS ====
2456 You MUST also set icp_port and icp_access explicitly when using these options.
2457 The defaults will prevent peer traffic using ICP.
2460 no-query Disable ICP queries to this neighbor.
2463 Indicates the named peer is a member of a multicast group.
2464 ICP queries will not be sent directly to the peer, but ICP
2465 replies will be accepted from it.
2467 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2468 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2471 To only send ICP queries to this neighbor infrequently.
2472 This is used to keep the neighbor round trip time updated
2473 and is usually used in conjunction with weighted-round-robin.
2476 ==== HTCP OPTIONS ====
2478 You MUST also set htcp_port and htcp_access explicitly when using these options.
2479 The defaults will prevent peer traffic using HTCP.
2482 htcp Send HTCP, instead of ICP, queries to the neighbor.
2483 You probably also want to set the "icp-port" to 4827
2484 instead of 3130. This directive accepts a comma separated
2485 list of options described below.
2487 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2489 htcp=no-clr Send HTCP to the neighbor but without
2490 sending any CLR requests. This cannot be used with
2493 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2494 This cannot be used with no-clr.
2497 Send HTCP to the neighbor including CLRs but only when
2498 they do not result from PURGE requests.
2501 Forward any HTCP CLR requests this proxy receives to the peer.
2504 ==== PEER SELECTION METHODS ====
2506 The default peer selection method is ICP, with the first responding peer
2507 being used as source. These options can be used for better load balancing.
2510 default This is a parent cache which can be used as a "last-resort"
2511 if a peer cannot be located by any of the peer-selection methods.
2512 If specified more than once, only the first is used.
2514 round-robin Load-Balance parents which should be used in a round-robin
2515 fashion in the absence of any ICP queries.
2516 weight=N can be used to add bias.
2518 weighted-round-robin
2519 Load-Balance parents which should be used in a round-robin
2520 fashion with the frequency of each parent being based on the
2521 round trip time. Closer parents are used more often.
2522 Usually used for background-ping parents.
2523 weight=N can be used to add bias.
2525 carp Load-Balance parents which should be used as a CARP array.
2526 The requests will be distributed among the parents based on the
2527 CARP load balancing hash function based on their weight.
2529 userhash Load-balance parents based on the client proxy_auth or ident username.
2531 sourcehash Load-balance parents based on the client source IP.
2534 To be used only for cache peers of type "multicast".
2535 ALL members of this multicast group have "sibling"
2536 relationship with it, not "parent". This is to a multicast
2537 group when the requested object would be fetched only from
2538 a "parent" cache, anyway. It's useful, e.g., when
2539 configuring a pool of redundant Squid proxies, being
2540 members of the same multicast group.
2543 ==== PEER SELECTION OPTIONS ====
2545 weight=N use to affect the selection of a peer during any weighted
2546 peer-selection mechanisms.
2547 The weight must be an integer; default is 1,
2548 larger weights are favored more.
2549 This option does not affect parent selection if a peering
2550 protocol is not in use.
2552 basetime=N Specify a base amount to be subtracted from round trip
2554 It is subtracted before division by weight in calculating
2555 which parent to fectch from. If the rtt is less than the
2556 base time the rtt is set to a minimal value.
2558 ttl=N Specify a TTL to use when sending multicast ICP queries
2560 Only useful when sending to a multicast group.
2561 Because we don't accept ICP replies from random
2562 hosts, you must configure other group members as
2563 peers with the 'multicast-responder' option.
2565 no-delay To prevent access to this neighbor from influencing the
2568 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2569 enabled) for this host from the specified URL rather
2570 than the Squid default location.
2573 ==== CARP OPTIONS ====
2575 carp-key=key-specification
2576 use a different key than the full URL to hash against the peer.
2577 the key-specification is a comma-separated list of the keywords
2578 scheme, host, port, path, params
2579 Order is not important.
2581 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2583 originserver Causes this parent to be contacted as an origin server.
2584 Meant to be used in accelerator setups when the peer
2588 Set the Host header of requests forwarded to this peer.
2589 Useful in accelerator setups where the server (peer)
2590 expects a certain domain name but clients may request
2591 others. ie example.com or www.example.com
2593 no-digest Disable request of cache digests.
2596 Disables requesting ICMP RTT database (NetDB).
2599 ==== AUTHENTICATION OPTIONS ====
2602 If this is a personal/workgroup proxy and your parent
2603 requires proxy authentication.
2605 Note: The string can include URL escapes (i.e. %20 for
2606 spaces). This also means % must be written as %%.
2609 Send login details received from client to this peer.
2610 Both Proxy- and WWW-Authorization headers are passed
2611 without alteration to the peer.
2612 Authentication is not required by Squid for this to work.
2614 Note: This will pass any form of authentication but
2615 only Basic auth will work through a proxy unless the
2616 connection-auth options are also used.
2618 login=PASS Send login details received from client to this peer.
2619 Authentication is not required by this option.
2621 If there are no client-provided authentication headers
2622 to pass on, but username and password are available
2623 from an external ACL user= and password= result tags
2624 they may be sent instead.
2626 Note: To combine this with proxy_auth both proxies must
2627 share the same user database as HTTP only allows for
2628 a single login (one for proxy, one for origin server).
2629 Also be warned this will expose your users proxy
2630 password to the peer. USE WITH CAUTION
2633 Send the username to the upstream cache, but with a
2634 fixed password. This is meant to be used when the peer
2635 is in another administrative domain, but it is still
2636 needed to identify each user.
2637 The star can optionally be followed by some extra
2638 information which is added to the username. This can
2639 be used to identify this proxy to the peer, similar to
2640 the login=username:password option above.
2643 If this is a personal/workgroup proxy and your parent
2644 requires a secure proxy authentication.
2645 The first principal from the default keytab or defined by
2646 the environment variable KRB5_KTNAME will be used.
2648 WARNING: The connection may transmit requests from multiple
2649 clients. Negotiate often assumes end-to-end authentication
2650 and a single-client. Which is not strictly true here.
2652 login=NEGOTIATE:principal_name
2653 If this is a personal/workgroup proxy and your parent
2654 requires a secure proxy authentication.
2655 The principal principal_name from the default keytab or
2656 defined by the environment variable KRB5_KTNAME will be
2659 WARNING: The connection may transmit requests from multiple
2660 clients. Negotiate often assumes end-to-end authentication
2661 and a single-client. Which is not strictly true here.
2663 connection-auth=on|off
2664 Tell Squid that this peer does or not support Microsoft
2665 connection oriented authentication, and any such
2666 challenges received from there should be ignored.
2667 Default is auto to automatically determine the status
2671 ==== SSL / HTTPS / TLS OPTIONS ====
2673 ssl Encrypt connections to this peer with SSL/TLS.
2675 sslcert=/path/to/ssl/certificate
2676 A client SSL certificate to use when connecting to
2679 sslkey=/path/to/ssl/key
2680 The private SSL key corresponding to sslcert above.
2681 If 'sslkey' is not specified 'sslcert' is assumed to
2682 reference a combined file containing both the
2683 certificate and the key.
2685 sslversion=1|2|3|4|5|6
2686 The SSL version to use when connecting to this peer
2687 1 = automatic (default)
2694 sslcipher=... The list of valid SSL ciphers to use when connecting
2697 ssloptions=... Specify various SSL implementation options:
2699 NO_SSLv2 Disallow the use of SSLv2
2700 NO_SSLv3 Disallow the use of SSLv3
2701 NO_TLSv1 Disallow the use of TLSv1.0
2702 NO_TLSv1_1 Disallow the use of TLSv1.1
2703 NO_TLSv1_2 Disallow the use of TLSv1.2
2705 Always create a new key when using
2706 temporary/ephemeral DH key exchanges
2707 ALL Enable various bug workarounds
2708 suggested as "harmless" by OpenSSL
2709 Be warned that this reduces SSL/TLS
2710 strength to some attacks.
2712 See the OpenSSL SSL_CTX_set_options documentation for a
2715 sslcafile=... A file containing additional CA certificates to use
2716 when verifying the peer certificate.
2718 sslcapath=... A directory containing additional CA certificates to
2719 use when verifying the peer certificate.
2721 sslcrlfile=... A certificate revocation list file to use when
2722 verifying the peer certificate.
2724 sslflags=... Specify various flags modifying the SSL implementation:
2727 Accept certificates even if they fail to
2730 Don't use the default CA list built in
2733 Don't verify the peer certificate
2734 matches the server name
2736 ssldomain= The peer name as advertised in it's certificate.
2737 Used for verifying the correctness of the received peer
2738 certificate. If not specified the peer hostname will be
2742 Enable the "Front-End-Https: On" header needed when
2743 using Squid as a SSL frontend in front of Microsoft OWA.
2744 See MS KB document Q307347 for details on this header.
2745 If set to auto the header will only be added if the
2746 request is forwarded as a https:// URL.
2749 ==== GENERAL OPTIONS ====
2752 A peer-specific connect timeout.
2753 Also see the peer_connect_timeout directive.
2755 connect-fail-limit=N
2756 How many times connecting to a peer must fail before
2757 it is marked as down. Default is 10.
2759 allow-miss Disable Squid's use of only-if-cached when forwarding
2760 requests to siblings. This is primarily useful when
2761 icp_hit_stale is used by the sibling. To extensive use
2762 of this option may result in forwarding loops, and you
2763 should avoid having two-way peerings with this option.
2764 For example to deny peer usage on requests from peer
2765 by denying cache_peer_access if the source is a peer.
2767 max-conn=N Limit the amount of connections Squid may open to this
2770 name=xxx Unique name for the peer.
2771 Required if you have multiple peers on the same host
2772 but different ports.
2773 This name can be used in cache_peer_access and similar
2774 directives to dentify the peer.
2775 Can be used by outgoing access controls through the
2778 no-tproxy Do not use the client-spoof TPROXY support when forwarding
2779 requests to this peer. Use normal address selection instead.
2781 proxy-only objects fetched from the peer will not be stored locally.
2785 NAME: cache_peer_domain cache_host_domain
2790 Use to limit the domains for which a neighbor cache will be
2793 cache_peer_domain cache-host domain [domain ...]
2794 cache_peer_domain cache-host !domain
2796 For example, specifying
2798 cache_peer_domain parent.foo.net .edu
2800 has the effect such that UDP query packets are sent to
2801 'bigserver' only when the requested object exists on a
2802 server in the .edu domain. Prefixing the domainname
2803 with '!' means the cache will be queried for objects
2806 NOTE: * Any number of domains may be given for a cache-host,
2807 either on the same or separate lines.
2808 * When multiple domains are given for a particular
2809 cache-host, the first matched domain is applied.
2810 * Cache hosts with no domain restrictions are queried
2812 * There are no defaults.
2813 * There is also a 'cache_peer_access' tag in the ACL
2817 NAME: cache_peer_access
2822 Similar to 'cache_peer_domain' but provides more flexibility by
2825 cache_peer_access cache-host allow|deny [!]aclname ...
2827 The syntax is identical to 'http_access' and the other lists of
2828 ACL elements. See the comments for 'http_access' below, or
2829 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
2832 NAME: neighbor_type_domain
2833 TYPE: hostdomaintype
2837 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
2839 Modifying the neighbor type for specific domains is now
2840 possible. You can treat some domains differently than the
2841 default neighbor type specified on the 'cache_peer' line.
2842 Normally it should only be necessary to list domains which
2843 should be treated differently because the default neighbor type
2844 applies for hostnames which do not match domains listed here.
2847 cache_peer cache.foo.org parent 3128 3130
2848 neighbor_type_domain cache.foo.org sibling .com .net
2849 neighbor_type_domain cache.foo.org sibling .au .de
2852 NAME: dead_peer_timeout
2856 LOC: Config.Timeout.deadPeer
2858 This controls how long Squid waits to declare a peer cache
2859 as "dead." If there are no ICP replies received in this
2860 amount of time, Squid will declare the peer dead and not
2861 expect to receive any further ICP replies. However, it
2862 continues to send ICP queries, and will mark the peer as
2863 alive upon receipt of the first subsequent ICP reply.
2865 This timeout also affects when Squid expects to receive ICP
2866 replies from peers. If more than 'dead_peer' seconds have
2867 passed since the last ICP reply was received, Squid will not
2868 expect to receive an ICP reply on the next query. Thus, if
2869 your time between requests is greater than this timeout, you
2870 will see a lot of requests sent DIRECT to origin servers
2871 instead of to your parents.
2874 NAME: forward_max_tries
2877 LOC: Config.forward_max_tries
2879 Controls how many different forward paths Squid will try
2880 before giving up. See also forward_timeout.
2882 NOTE: connect_retries (default: none) can make each of these
2883 possible forwarding paths be tried multiple times.
2886 NAME: hierarchy_stoplist
2889 LOC: Config.hierarchy_stoplist
2891 A list of words which, if found in a URL, cause the object to
2892 be handled directly by this cache. In other words, use this
2893 to not query neighbor caches for certain objects. You may
2894 list this option multiple times.
2897 hierarchy_stoplist cgi-bin ?
2899 Note: never_direct overrides this option.
2903 MEMORY CACHE OPTIONS
2904 -----------------------------------------------------------------------------
2911 LOC: Config.memMaxSize
2913 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
2914 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
2915 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
2916 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
2918 'cache_mem' specifies the ideal amount of memory to be used
2920 * In-Transit objects
2922 * Negative-Cached objects
2924 Data for these objects are stored in 4 KB blocks. This
2925 parameter specifies the ideal upper limit on the total size of
2926 4 KB blocks allocated. In-Transit objects take the highest
2929 In-transit objects have priority over the others. When
2930 additional space is needed for incoming data, negative-cached
2931 and hot objects will be released. In other words, the
2932 negative-cached and hot objects will fill up any unused space
2933 not needed for in-transit objects.
2935 If circumstances require, this limit will be exceeded.
2936 Specifically, if your incoming request rate requires more than
2937 'cache_mem' of memory to hold in-transit objects, Squid will
2938 exceed this limit to satisfy the new requests. When the load
2939 decreases, blocks will be freed until the high-water mark is
2940 reached. Thereafter, blocks will be used to store hot
2943 If shared memory caching is enabled, Squid does not use the shared
2944 cache space for in-transit objects, but they still consume as much
2945 local memory as they need. For more details about the shared memory
2946 cache, see memory_cache_shared.
2949 NAME: maximum_object_size_in_memory
2953 LOC: Config.Store.maxInMemObjSize
2955 Objects greater than this size will not be attempted to kept in
2956 the memory cache. This should be set high enough to keep objects
2957 accessed frequently in memory to improve performance whilst low
2958 enough to keep larger objects from hoarding cache_mem.
2961 NAME: memory_cache_shared
2964 LOC: Config.memShared
2966 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
2968 Controls whether the memory cache is shared among SMP workers.
2970 The shared memory cache is meant to occupy cache_mem bytes and replace
2971 the non-shared memory cache, although some entities may still be
2972 cached locally by workers for now (e.g., internal and in-transit
2973 objects may be served from a local memory cache even if shared memory
2974 caching is enabled).
2976 By default, the memory cache is shared if and only if all of the
2977 following conditions are satisfied: Squid runs in SMP mode with
2978 multiple workers, cache_mem is positive, and Squid environment
2979 supports required IPC primitives (e.g., POSIX shared memory segments
2980 and GCC-style atomic operations).
2982 To avoid blocking locks, shared memory uses opportunistic algorithms
2983 that do not guarantee that every cachable entity that could have been
2984 shared among SMP workers will actually be shared.
2986 Currently, entities exceeding 32KB in size cannot be shared.
2989 NAME: memory_cache_mode
2994 Controls which objects to keep in the memory cache (cache_mem)
2996 always Keep most recently fetched objects in memory (default)
2998 disk Only disk cache hits are kept in memory, which means
2999 an object must first be cached on disk and then hit
3000 a second time before cached in memory.
3002 network Only objects fetched from network is kept in memory
3005 NAME: memory_replacement_policy
3007 LOC: Config.memPolicy
3010 The memory replacement policy parameter determines which
3011 objects are purged from memory when memory space is needed.
3013 See cache_replacement_policy for details.
3018 -----------------------------------------------------------------------------
3021 NAME: cache_replacement_policy
3023 LOC: Config.replPolicy
3026 The cache replacement policy parameter determines which
3027 objects are evicted (replaced) when disk space is needed.
3029 lru : Squid's original list based LRU policy
3030 heap GDSF : Greedy-Dual Size Frequency
3031 heap LFUDA: Least Frequently Used with Dynamic Aging
3032 heap LRU : LRU policy implemented using a heap
3034 Applies to any cache_dir lines listed below this.
3036 The LRU policies keeps recently referenced objects.
3038 The heap GDSF policy optimizes object hit rate by keeping smaller
3039 popular objects in cache so it has a better chance of getting a
3040 hit. It achieves a lower byte hit rate than LFUDA though since
3041 it evicts larger (possibly popular) objects.
3043 The heap LFUDA policy keeps popular objects in cache regardless of
3044 their size and thus optimizes byte hit rate at the expense of
3045 hit rate since one large, popular object will prevent many
3046 smaller, slightly less popular objects from being cached.
3048 Both policies utilize a dynamic aging mechanism that prevents
3049 cache pollution that can otherwise occur with frequency-based
3050 replacement policies.
3052 NOTE: if using the LFUDA replacement policy you should increase
3053 the value of maximum_object_size above its default of 4096 KB to
3054 to maximize the potential byte hit rate improvement of LFUDA.
3056 For more information about the GDSF and LFUDA cache replacement
3057 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3058 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3064 LOC: Config.cacheSwap
3068 cache_dir Type Directory-Name Fs-specific-data [options]
3070 You can specify multiple cache_dir lines to spread the
3071 cache among different disk partitions.
3073 Type specifies the kind of storage system to use. Only "ufs"
3074 is built by default. To enable any of the other storage systems
3075 see the --enable-storeio configure option.
3077 'Directory' is a top-level directory where cache swap
3078 files will be stored. If you want to use an entire disk
3079 for caching, this can be the mount-point directory.
3080 The directory must exist and be writable by the Squid
3081 process. Squid will NOT create this directory for you.
3083 In SMP configurations, cache_dir must not precede the workers option
3084 and should use configuration macros or conditionals to give each
3085 worker interested in disk caching a dedicated cache directory.
3089 "ufs" is the old well-known Squid storage format that has always
3092 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3094 'Mbytes' is the amount of disk space (MB) to use under this
3095 directory. The default is 100 MB. Change this to suit your
3096 configuration. Do NOT put the size of your disk drive here.
3097 Instead, if you want Squid to use the entire disk drive,
3098 subtract 20% and use that value.
3100 'L1' is the number of first-level subdirectories which
3101 will be created under the 'Directory'. The default is 16.
3103 'L2' is the number of second-level subdirectories which
3104 will be created under each first-level directory. The default
3107 The aufs store type:
3109 "aufs" uses the same storage format as "ufs", utilizing
3110 POSIX-threads to avoid blocking the main Squid process on
3111 disk-I/O. This was formerly known in Squid as async-io.
3113 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3115 see argument descriptions under ufs above
3117 The diskd store type:
3119 "diskd" uses the same storage format as "ufs", utilizing a
3120 separate process to avoid blocking the main Squid process on
3123 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3125 see argument descriptions under ufs above
3127 Q1 specifies the number of unacknowledged I/O requests when Squid
3128 stops opening new files. If this many messages are in the queues,
3129 Squid won't open new files. Default is 64
3131 Q2 specifies the number of unacknowledged messages when Squid
3132 starts blocking. If this many messages are in the queues,
3133 Squid blocks until it receives some replies. Default is 72
3135 When Q1 < Q2 (the default), the cache directory is optimized
3136 for lower response time at the expense of a decrease in hit
3137 ratio. If Q1 > Q2, the cache directory is optimized for
3138 higher hit ratio at the expense of an increase in response
3141 The rock store type:
3143 cache_dir rock Directory-Name Mbytes <max-size=bytes> [options]
3145 The Rock Store type is a database-style storage. All cached
3146 entries are stored in a "database" file, using fixed-size slots,
3147 one entry per slot. The database size is specified in MB. The
3148 slot size is specified in bytes using the max-size option. See
3149 below for more info on the max-size option.
3151 swap-timeout=msec: Squid will not start writing a miss to or
3152 reading a hit from disk if it estimates that the swap operation
3153 will take more than the specified number of milliseconds. By
3154 default and when set to zero, disables the disk I/O time limit
3155 enforcement. Ignored when using blocking I/O module because
3156 blocking synchronous I/O does not allow Squid to estimate the
3157 expected swap wait time.
3159 max-swap-rate=swaps/sec: Artificially limits disk access using
3160 the specified I/O rate limit. Swap out requests that
3161 would cause the average I/O rate to exceed the limit are
3162 delayed. Individual swap in requests (i.e., hits or reads) are
3163 not delayed, but they do contribute to measured swap rate and
3164 since they are placed in the same FIFO queue as swap out
3165 requests, they may wait longer if max-swap-rate is smaller.
3166 This is necessary on file systems that buffer "too
3167 many" writes and then start blocking Squid and other processes
3168 while committing those writes to disk. Usually used together
3169 with swap-timeout to avoid excessive delays and queue overflows
3170 when disk demand exceeds available disk "bandwidth". By default
3171 and when set to zero, disables the disk I/O rate limit
3172 enforcement. Currently supported by IpcIo module only.
3175 The coss store type:
3177 NP: COSS filesystem in Squid-3 has been deemed too unstable for
3178 production use and has thus been removed from this release.
3179 We hope that it can be made usable again soon.
3181 block-size=n defines the "block size" for COSS cache_dir's.
3182 Squid uses file numbers as block numbers. Since file numbers
3183 are limited to 24 bits, the block size determines the maximum
3184 size of the COSS partition. The default is 512 bytes, which
3185 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
3186 you should not change the coss block size after Squid
3187 has written some objects to the cache_dir.
3189 The coss file store has changed from 2.5. Now it uses a file
3190 called 'stripe' in the directory names in the config - and
3191 this will be created by squid -z.
3195 no-store, no new objects should be stored to this cache_dir
3197 min-size=n, refers to the min object size in bytes this cache_dir
3198 will accept. It's used to restrict a cache_dir to only store
3199 large objects (e.g. aufs) while other storedirs are optimized
3200 for smaller objects (e.g. COSS). Defaults to 0.
3202 max-size=n, refers to the max object size in bytes this cache_dir
3203 supports. It is used to select the cache_dir to store the object.
3204 Note: To make optimal use of the max-size limits you should order
3205 the cache_dir lines with the smallest max-size value first and the
3206 ones with no max-size specification last.
3208 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
3209 which can be changed with the --with-coss-membuf-size=N configure
3213 # Uncomment and adjust the following to add a disk cache directory.
3214 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3218 NAME: store_dir_select_algorithm
3220 LOC: Config.store_dir_select_algorithm
3223 Set this to 'round-robin' as an alternative.
3226 NAME: max_open_disk_fds
3228 LOC: Config.max_open_disk_fds
3231 To avoid having disk as the I/O bottleneck Squid can optionally
3232 bypass the on-disk cache if more than this amount of disk file
3233 descriptors are open.
3235 A value of 0 indicates no limit.
3238 NAME: minimum_object_size
3242 LOC: Config.Store.minObjectSize
3244 Objects smaller than this size will NOT be saved on disk. The
3245 value is specified in kilobytes, and the default is 0 KB, which
3246 means there is no minimum.
3249 NAME: maximum_object_size
3253 LOC: Config.Store.maxObjectSize
3255 Objects larger than this size will NOT be saved on disk. The
3256 value is specified in kilobytes, and the default is 4MB. If
3257 you wish to get a high BYTES hit ratio, you should probably
3258 increase this (one 32 MB object hit counts for 3200 10KB
3259 hits). If you wish to increase speed more than your want to
3260 save bandwidth you should leave this low.
3262 NOTE: if using the LFUDA replacement policy you should increase
3263 this value to maximize the byte hit rate improvement of LFUDA!
3264 See replacement_policy below for a discussion of this policy.
3267 NAME: cache_swap_low
3268 COMMENT: (percent, 0-100)
3271 LOC: Config.Swap.lowWaterMark
3274 NAME: cache_swap_high
3275 COMMENT: (percent, 0-100)
3278 LOC: Config.Swap.highWaterMark
3281 The low- and high-water marks for cache object replacement.
3282 Replacement begins when the swap (disk) usage is above the
3283 low-water mark and attempts to maintain utilization near the
3284 low-water mark. As swap utilization gets close to high-water
3285 mark object eviction becomes more aggressive. If utilization is
3286 close to the low-water mark less replacement is done each time.
3288 Defaults are 90% and 95%. If you have a large cache, 5% could be
3289 hundreds of MB. If this is the case you may wish to set these
3290 numbers closer together.
3295 -----------------------------------------------------------------------------
3305 logformat <name> <format specification>
3307 Defines an access log format.
3309 The <format specification> is a string with embedded % format codes
3311 % format codes all follow the same basic structure where all but
3312 the formatcode is optional. Output strings are automatically escaped
3313 as required according to their context and the output format
3314 modifiers are usually not needed, but can be specified if an explicit
3315 output format is desired.
3317 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3319 " output in quoted string format
3320 [ output in squid text log format as used by log_mime_hdrs
3321 # output in URL quoted format
3326 width minimum and/or maximum field width:
3327 [width_min][.width_max]
3328 When minimum starts with 0, the field is zero-padded.
3329 String values exceeding maximum width are truncated.
3331 {arg} argument such as header name etc
3335 % a literal % character
3336 sn Unique sequence number per log line entry
3337 err_code The ID of an error response served by Squid or
3338 a similar internal error identifier.
3339 err_detail Additional err_code-dependent error information.
3340 note The meta header specified by the argument. Also
3341 logs the adaptation meta headers set by the
3342 adaptation_meta configuration parameter.
3343 If no argument given all meta headers logged.
3345 Connection related format codes:
3347 >a Client source IP address
3349 >p Client source port
3350 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3351 >la Local IP address the client connected to
3352 >lp Local port number the client connected to
3354 la Local listening IP address the client connection was connected to.
3355 lp Local listening port number the client connection was connected to.
3357 <a Server IP address of the last server or peer connection
3358 <A Server FQDN or peer name
3359 <p Server port number of the last server or peer connection
3360 <la Local IP address of the last server or peer connection
3361 <lp Local port number of the last server or peer connection
3363 Time related format codes:
3365 ts Seconds since epoch
3366 tu subsecond time (milliseconds)
3367 tl Local time. Optional strftime format argument
3368 default %d/%b/%Y:%H:%M:%S %z
3369 tg GMT time. Optional strftime format argument
3370 default %d/%b/%Y:%H:%M:%S %z
3371 tr Response time (milliseconds)
3372 dt Total time spent making DNS lookups (milliseconds)
3374 Access Control related format codes:
3376 et Tag returned by external acl
3377 ea Log string returned by external acl
3378 un User name (any available)
3379 ul User name from authentication
3380 ue User name from external acl helper
3381 ui User name from ident
3382 us User name from SSL
3384 HTTP related format codes:
3386 [http::]>h Original request header. Optional header name argument
3387 on the format header[:[separator]element]
3388 [http::]>ha The HTTP request headers after adaptation and redirection.
3389 Optional header name argument as for >h
3390 [http::]<h Reply header. Optional header name argument
3392 [http::]>Hs HTTP status code sent to the client
3393 [http::]<Hs HTTP status code received from the next hop
3394 [http::]<bs Number of HTTP-equivalent message body bytes
3395 received from the next hop, excluding chunked
3396 transfer encoding and control messages.
3397 Generated FTP/Gopher listings are treated as
3399 [http::]mt MIME content type
3400 [http::]rm Request method (GET/POST etc)
3401 [http::]>rm Request method from client
3402 [http::]<rm Request method sent to server or peer
3403 [http::]ru Request URL from client (historic, filtered for logging)
3404 [http::]>ru Request URL from client
3405 [http::]<ru Request URL sent to server or peer
3406 [http::]rp Request URL-Path excluding hostname
3407 [http::]>rp Request URL-Path excluding hostname from client
3408 [http::]<rp Request URL-Path excluding hostname sento to server or peer
3409 [http::]rv Request protocol version
3410 [http::]>rv Request protocol version from client
3411 [http::]<rv Request protocol version sent to server or peer
3412 [http::]<st Sent reply size including HTTP headers
3413 [http::]>st Received request size including HTTP headers. In the
3414 case of chunked requests the chunked encoding metadata
3416 [http::]>sh Received HTTP request headers size
3417 [http::]<sh Sent HTTP reply headers size
3418 [http::]st Request+Reply size including HTTP headers
3419 [http::]<sH Reply high offset sent
3420 [http::]<sS Upstream object size
3421 [http::]<pt Peer response time in milliseconds. The timer starts
3422 when the last request byte is sent to the next hop
3423 and stops when the last response byte is received.
3424 [http::]<tt Total server-side time in milliseconds. The timer
3425 starts with the first connect request (or write I/O)
3426 sent to the first selected peer. The timer stops
3427 with the last I/O with the last peer.
3429 Squid handling related format codes:
3431 Ss Squid request status (TCP_MISS etc)
3432 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3434 SSL-related format codes:
3436 ssl::bump_mode SslBump decision for the transaction:
3438 For CONNECT requests that initiated bumping of
3439 a connection and for any request received on
3440 an already bumped connection, Squid logs the
3441 corresponding SslBump mode ("server-first" or
3442 "client-first"). See the ssl_bump option for
3443 more information about these modes.
3445 A "none" token is logged for requests that
3446 triggered "ssl_bump" ACL evaluation matching
3447 either a "none" rule or no rules at all.
3449 In all other cases, a single dash ("-") is
3452 If ICAP is enabled, the following code becomes available (as
3453 well as ICAP log codes documented with the icap_log option):
3455 icap::tt Total ICAP processing time for the HTTP
3456 transaction. The timer ticks when ICAP
3457 ACLs are checked and when ICAP
3458 transaction is in progress.
3460 If adaptation is enabled the following three codes become available:
3462 adapt::<last_h The header of the last ICAP response or
3463 meta-information from the last eCAP
3464 transaction related to the HTTP transaction.
3465 Like <h, accepts an optional header name
3468 adapt::sum_trs Summed adaptation transaction response
3469 times recorded as a comma-separated list in
3470 the order of transaction start time. Each time
3471 value is recorded as an integer number,
3472 representing response time of one or more
3473 adaptation (ICAP or eCAP) transaction in
3474 milliseconds. When a failed transaction is
3475 being retried or repeated, its time is not
3476 logged individually but added to the
3477 replacement (next) transaction. See also:
3480 adapt::all_trs All adaptation transaction response times.
3481 Same as adaptation_strs but response times of
3482 individual transactions are never added
3483 together. Instead, all transaction response
3484 times are recorded individually.
3486 You can prefix adapt::*_trs format codes with adaptation
3487 service name in curly braces to record response time(s) specific
3488 to that service. For example: %{my_service}adapt::sum_trs
3490 If SSL is enabled, the following formating codes become available:
3492 %ssl::>cert_subject The Subject field of the received client
3493 SSL certificate or a dash ('-') if Squid has
3494 received an invalid/malformed certificate or
3495 no certificate at all. Consider encoding the
3496 logged value because Subject often has spaces.
3498 %ssl::>cert_issuer The Issuer field of the received client
3499 SSL certificate or a dash ('-') if Squid has
3500 received an invalid/malformed certificate or
3501 no certificate at all. Consider encoding the
3502 logged value because Issuer often has spaces.
3504 The default formats available (which do not need re-defining) are:
3506 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3507 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3508 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3509 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3510 logformat useragent %>a [%tl] "%{User-Agent}>h"
3512 NOTE: When the log_mime_hdrs directive is set to ON.
3513 The squid, common and combined formats have a safely encoded copy
3514 of the mime headers appended to each line within a pair of brackets.
3516 NOTE: The common and combined formats are not quite true to the Apache definition.
3517 The logs from Squid contain an extra status and hierarchy code appended.
3521 NAME: access_log cache_access_log
3523 LOC: Config.Log.accesslogs
3524 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3526 These files log client request activities. Has a line every HTTP or
3527 ICP request. The format is:
3528 access_log <module>:<place> [<logformat name> [acl acl ...]]
3529 access_log none [acl acl ...]]
3531 Will log to the specified module:place using the specified format (which
3532 must be defined in a logformat directive) those entries which match
3533 ALL the acl's specified (which must be defined in acl clauses).
3534 If no acl is specified, all requests will be logged to this destination.
3536 ===== Modules Currently available =====
3538 none Do not log any requests matching these ACL.
3539 Do not specify Place or logformat name.
3541 stdio Write each log line to disk immediately at the completion of
3543 Place: the filename and path to be written.
3545 daemon Very similar to stdio. But instead of writing to disk the log
3546 line is passed to a daemon helper for asychronous handling instead.
3547 Place: varies depending on the daemon.
3549 log_file_daemon Place: the file name and path to be written.
3551 syslog To log each request via syslog facility.
3552 Place: The syslog facility and priority level for these entries.
3553 Place Format: facility.priority
3555 where facility could be any of:
3556 authpriv, daemon, local0 ... local7 or user.
3558 And priority could be any of:
3559 err, warning, notice, info, debug.
3561 udp To send each log line as text data to a UDP receiver.
3562 Place: The destination host name or IP and port.
3563 Place Format: //host:port
3565 tcp To send each log line as text data to a TCP receiver.
3566 Place: The destination host name or IP and port.
3567 Place Format: //host:port
3570 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3576 LOC: Config.Log.icaplogs
3579 ICAP log files record ICAP transaction summaries, one line per
3582 The icap_log option format is:
3583 icap_log <filepath> [<logformat name> [acl acl ...]]
3584 icap_log none [acl acl ...]]
3586 Please see access_log option documentation for details. The two
3587 kinds of logs share the overall configuration approach and many
3590 ICAP processing of a single HTTP message or transaction may
3591 require multiple ICAP transactions. In such cases, multiple
3592 ICAP transaction log lines will correspond to a single access
3595 ICAP log uses logformat codes that make sense for an ICAP
3596 transaction. Header-related codes are applied to the HTTP header
3597 embedded in an ICAP server response, with the following caveats:
3598 For REQMOD, there is no HTTP response header unless the ICAP
3599 server performed request satisfaction. For RESPMOD, the HTTP
3600 request header is the header sent to the ICAP server. For
3601 OPTIONS, there are no HTTP headers.
3603 The following format codes are also available for ICAP logs:
3605 icap::<A ICAP server IP address. Similar to <A.
3607 icap::<service_name ICAP service name from the icap_service
3608 option in Squid configuration file.
3610 icap::ru ICAP Request-URI. Similar to ru.
3612 icap::rm ICAP request method (REQMOD, RESPMOD, or
3613 OPTIONS). Similar to existing rm.
3615 icap::>st Bytes sent to the ICAP server (TCP payload
3616 only; i.e., what Squid writes to the socket).
3618 icap::<st Bytes received from the ICAP server (TCP
3619 payload only; i.e., what Squid reads from
3622 icap::<bs Number of message body bytes received from the
3623 ICAP server. ICAP message body, if any, usually
3624 includes encapsulated HTTP message headers and
3625 possibly encapsulated HTTP message body. The
3626 HTTP body part is dechunked before its size is
3629 icap::tr Transaction response time (in
3630 milliseconds). The timer starts when
3631 the ICAP transaction is created and
3632 stops when the transaction is completed.
3635 icap::tio Transaction I/O time (in milliseconds). The
3636 timer starts when the first ICAP request
3637 byte is scheduled for sending. The timers
3638 stops when the last byte of the ICAP response
3641 icap::to Transaction outcome: ICAP_ERR* for all
3642 transaction errors, ICAP_OPT for OPTION
3643 transactions, ICAP_ECHO for 204
3644 responses, ICAP_MOD for message
3645 modification, and ICAP_SAT for request
3646 satisfaction. Similar to Ss.
3648 icap::Hs ICAP response status code. Similar to Hs.
3650 icap::>h ICAP request header(s). Similar to >h.
3652 icap::<h ICAP response header(s). Similar to <h.
3654 The default ICAP log format, which can be used without an explicit
3655 definition, is called icap_squid:
3657 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3659 See also: logformat, log_icap, and %adapt::<last_h
3662 NAME: logfile_daemon
3664 DEFAULT: @DEFAULT_LOGFILED@
3665 LOC: Log::TheConfig.logfile_daemon
3667 Specify the path to the logfile-writing daemon. This daemon is
3668 used to write the access and store logs, if configured.
3670 Squid sends a number of commands to the log daemon:
3671 L<data>\n - logfile data
3676 r<n>\n - set rotate count to <n>
3677 b<n>\n - 1 = buffer output, 0 = don't buffer output
3679 No responses is expected.
3684 LOC: Config.accessList.log
3686 COMMENT: allow|deny acl acl...
3688 This options allows you to control which requests gets logged
3689 to access.log (see access_log directive). Requests denied for
3690 logging will also not be accounted for in performance counters.
3692 This clause only supports fast acl types.
3693 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3699 LOC: Config.accessList.icap
3702 This options allows you to control which requests get logged
3703 to icap.log. See the icap_log directive for ICAP log details.
3706 NAME: cache_store_log
3709 LOC: Config.Log.store
3711 Logs the activities of the storage manager. Shows which
3712 objects are ejected from the cache, and which objects are
3713 saved and for how long.
3714 There are not really utilities to analyze this data, so you can safely
3715 disable it (the default).
3717 Store log uses modular logging outputs. See access_log for the list
3718 of modules supported.
3721 cache_store_log stdio:@DEFAULT_STORE_LOG@
3722 cache_store_log daemon:@DEFAULT_STORE_LOG@
3725 NAME: cache_swap_state cache_swap_log
3727 LOC: Config.Log.swap
3730 Location for the cache "swap.state" file. This index file holds
3731 the metadata of objects saved on disk. It is used to rebuild
3732 the cache during startup. Normally this file resides in each
3733 'cache_dir' directory, but you may specify an alternate
3734 pathname here. Note you must give a full filename, not just
3735 a directory. Since this is the index for the whole object
3736 list you CANNOT periodically rotate it!
3738 If %s can be used in the file name it will be replaced with a
3739 a representation of the cache_dir name where each / is replaced
3740 with '.'. This is needed to allow adding/removing cache_dir
3741 lines when cache_swap_log is being used.
3743 If have more than one 'cache_dir', and %s is not used in the name
3744 these swap logs will have names such as:
3750 The numbered extension (which is added automatically)
3751 corresponds to the order of the 'cache_dir' lines in this
3752 configuration file. If you change the order of the 'cache_dir'
3753 lines in this file, these index files will NOT correspond to
3754 the correct 'cache_dir' entry (unless you manually rename
3755 them). We recommend you do NOT use this option. It is
3756 better to keep these index files in each 'cache_dir' directory.
3759 NAME: logfile_rotate
3762 LOC: Config.Log.rotateNumber
3764 Specifies the number of logfile rotations to make when you
3765 type 'squid -k rotate'. The default is 10, which will rotate
3766 with extensions 0 through 9. Setting logfile_rotate to 0 will
3767 disable the file name rotation, but the logfiles are still closed
3768 and re-opened. This will enable you to rename the logfiles
3769 yourself just before sending the rotate signal.
3771 Note, the 'squid -k rotate' command normally sends a USR1
3772 signal to the running squid process. In certain situations
3773 (e.g. on Linux with Async I/O), USR1 is used for other
3774 purposes, so -k rotate uses another signal. It is best to get
3775 in the habit of using 'squid -k rotate' instead of 'kill -USR1
3778 Note, from Squid-3.1 this option has no effect on the cache.log,
3779 that log can be rotated separately by using debug_options
3782 NAME: emulate_httpd_log
3785 Replace this with an access_log directive using the format 'common' or 'combined'.
3788 NAME: log_ip_on_direct
3791 Remove this option from your config. To log server or peer names use %<A in the log format.
3796 DEFAULT: @DEFAULT_MIME_TABLE@
3797 LOC: Config.mimeTablePathname
3799 Pathname to Squid's MIME table. You shouldn't need to change
3800 this, but the default file contains examples and formatting
3801 information if you do.
3807 LOC: Config.onoff.log_mime_hdrs
3810 The Cache can record both the request and the response MIME
3811 headers for each HTTP transaction. The headers are encoded
3812 safely and will appear as two bracketed fields at the end of
3813 the access log (for either the native or httpd-emulated log
3814 formats). To enable this logging set log_mime_hdrs to 'on'.
3820 Replace this with an access_log directive using the format 'useragent'.
3823 NAME: referer_log referrer_log
3826 Replace this with an access_log directive using the format 'referrer'.
3831 DEFAULT: @DEFAULT_PID_FILE@
3832 LOC: Config.pidFilename
3834 A filename to write the process-id to. To disable, enter "none".
3840 Remove this option from your config. To log FQDN use %>A in the log format.
3843 NAME: client_netmask
3845 LOC: Config.Addrs.client_netmask
3848 A netmask for client addresses in logfiles and cachemgr output.
3849 Change this to protect the privacy of your cache clients.
3850 A netmask of 255.255.255.0 will log all IP's in that range with
3851 the last digit set to '0'.
3857 Use a regular access.log with ACL limiting it to MISS events.
3860 NAME: strip_query_terms
3862 LOC: Config.onoff.strip_query_terms
3865 By default, Squid strips query terms from requested URLs before
3866 logging. This protects your user's privacy.
3873 LOC: Config.onoff.buffered_logs
3875 cache.log log file is written with stdio functions, and as such
3876 it can be buffered or unbuffered. By default it will be unbuffered.
3877 Buffering it can speed up the writing slightly (though you are
3878 unlikely to need to worry unless you run with tons of debugging
3879 enabled in which case performance will suffer badly anyway..).
3882 NAME: netdb_filename
3884 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
3885 LOC: Config.netdbFilename
3888 A filename where Squid stores it's netdb state between restarts.
3889 To disable, enter "none".
3893 OPTIONS FOR TROUBLESHOOTING
3894 -----------------------------------------------------------------------------
3899 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
3900 LOC: Debug::cache_log
3902 Cache logging file. This is where general information about
3903 your cache's behavior goes. You can increase the amount of data
3904 logged to this file and how often its rotated with "debug_options"
3910 LOC: Debug::debugOptions
3912 Logging options are set as section,level where each source file
3913 is assigned a unique section. Lower levels result in less
3914 output, Full debugging (level 9) can result in a very large
3915 log file, so be careful.
3917 The magic word "ALL" sets debugging levels for all sections.
3918 We recommend normally running with "ALL,1".
3920 The rotate=N option can be used to keep more or less of these logs
3921 than would otherwise be kept by logfile_rotate.
3922 For most uses a single log should be enough to monitor current
3923 events affecting Squid.
3928 LOC: Config.coredump_dir
3929 DEFAULT_IF_NONE: none
3931 By default Squid leaves core files in the directory from where
3932 it was started. If you set 'coredump_dir' to a directory
3933 that exists, Squid will chdir() to that directory at startup
3934 and coredump files will be left there.
3938 # Leave coredumps in the first cache dir
3939 coredump_dir @DEFAULT_SWAP_DIR@
3945 OPTIONS FOR FTP GATEWAYING
3946 -----------------------------------------------------------------------------
3952 LOC: Config.Ftp.anon_user
3954 If you want the anonymous login password to be more informative
3955 (and enable the use of picky ftp servers), set this to something
3956 reasonable for your domain, like wwwuser@somewhere.net
3958 The reason why this is domainless by default is the
3959 request can be made on the behalf of a user in any domain,
3960 depending on how the cache is used.
3961 Some ftp server also validate the email address is valid
3962 (for example perl.com).
3968 LOC: Config.Ftp.passive
3970 If your firewall does not allow Squid to use passive
3971 connections, turn off this option.
3973 Use of ftp_epsv_all option requires this to be ON.
3979 LOC: Config.Ftp.epsv_all
3981 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
3983 NATs may be able to put the connection on a "fast path" through the
3984 translator, as the EPRT command will never be used and therefore,
3985 translation of the data portion of the segments will never be needed.
3987 When a client only expects to do two-way FTP transfers this may be
3989 If squid finds that it must do a three-way FTP transfer after issuing
3990 an EPSV ALL command, the FTP session will fail.
3992 If you have any doubts about this option do not use it.
3993 Squid will nicely attempt all other connection methods.
3995 Requires ftp_passive to be ON (default) for any effect.
4001 LOC: Config.Ftp.epsv
4003 FTP Protocol extensions permit the use of a special "EPSV" command.
4005 NATs may be able to put the connection on a "fast path" through the
4006 translator using EPSV, as the EPRT command will never be used
4007 and therefore, translation of the data portion of the segments
4008 will never be needed.
4010 Turning this OFF will prevent EPSV being attempted.
4011 WARNING: Doing so will convert Squid back to the old behavior with all
4012 the related problems with external NAT devices/layers.
4014 Requires ftp_passive to be ON (default) for any effect.
4020 LOC: Config.Ftp.eprt
4022 FTP Protocol extensions permit the use of a special "EPRT" command.
4024 This extension provides a protocol neutral alternative to the
4025 IPv4-only PORT command. When supported it enables active FTP data
4026 channels over IPv6 and efficient NAT handling.
4028 Turning this OFF will prevent EPRT being attempted and will skip
4029 straight to using PORT for IPv4 servers.
4031 Some devices are known to not handle this extension correctly and
4032 may result in crashes. Devices which suport EPRT enough to fail
4033 cleanly will result in Squid attempting PORT anyway. This directive
4034 should only be disabled when EPRT results in device failures.
4036 WARNING: Doing so will convert Squid back to the old behavior with all
4037 the related problems with external NAT devices/layers and IPv4-only FTP.
4040 NAME: ftp_sanitycheck
4043 LOC: Config.Ftp.sanitycheck
4045 For security and data integrity reasons Squid by default performs
4046 sanity checks of the addresses of FTP data connections ensure the
4047 data connection is to the requested server. If you need to allow
4048 FTP connections to servers using another IP address for the data
4049 connection turn this off.
4052 NAME: ftp_telnet_protocol
4055 LOC: Config.Ftp.telnet
4057 The FTP protocol is officially defined to use the telnet protocol
4058 as transport channel for the control connection. However, many
4059 implementations are broken and does not respect this aspect of
4062 If you have trouble accessing files with ASCII code 255 in the
4063 path or similar problems involving this ASCII code you can
4064 try setting this directive to off. If that helps, report to the
4065 operator of the FTP server in question that their FTP server
4066 is broken and does not follow the FTP standard.
4070 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4071 -----------------------------------------------------------------------------
4076 DEFAULT: @DEFAULT_DISKD@
4077 LOC: Config.Program.diskd
4079 Specify the location of the diskd executable.
4080 Note this is only useful if you have compiled in
4081 diskd as one of the store io modules.
4084 NAME: unlinkd_program
4087 DEFAULT: @DEFAULT_UNLINKD@
4088 LOC: Config.Program.unlinkd
4090 Specify the location of the executable for file deletion process.
4093 NAME: pinger_program
4095 DEFAULT: @DEFAULT_PINGER@
4096 LOC: Config.pinger.program
4099 Specify the location of the executable for the pinger process.
4105 LOC: Config.pinger.enable
4108 Control whether the pinger is active at run-time.
4109 Enables turning ICMP pinger on and off with a simple
4110 squid -k reconfigure.
4115 OPTIONS FOR URL REWRITING
4116 -----------------------------------------------------------------------------
4119 NAME: url_rewrite_program redirect_program
4121 LOC: Config.Program.redirect
4124 Specify the location of the executable URL rewriter to use.
4125 Since they can perform almost any function there isn't one included.
4127 For each requested URL, the rewriter will receive on line with the format
4129 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
4131 In the future, the rewriter interface will be extended with
4132 key=value pairs ("kvpairs" shown above). Rewriter programs
4133 should be prepared to receive and possibly ignore additional
4134 whitespace-separated tokens on each input line.
4136 And the rewriter may return a rewritten URL. The other components of
4137 the request line does not need to be returned (ignored if they are).
4139 The rewriter can also indicate that a client-side redirect should
4140 be performed to the new URL. This is done by prefixing the returned
4141 URL with "301:" (moved permanently) or 302: (moved temporarily), etc.
4143 By default, a URL rewriter is not used.
4146 NAME: url_rewrite_children redirect_children
4147 TYPE: HelperChildConfig
4148 DEFAULT: 20 startup=0 idle=1 concurrency=0
4149 LOC: Config.redirectChildren
4151 The maximum number of redirector processes to spawn. If you limit
4152 it too few Squid will have to wait for them to process a backlog of
4153 URLs, slowing it down. If you allow too many they will use RAM
4154 and other system resources noticably.
4156 The startup= and idle= options allow some measure of skew in your
4161 Sets a minimum of how many processes are to be spawned when Squid
4162 starts or reconfigures. When set to zero the first request will
4163 cause spawning of the first child process to handle it.
4165 Starting too few will cause an initial slowdown in traffic as Squid
4166 attempts to simultaneously spawn enough processes to cope.
4170 Sets a minimum of how many processes Squid is to try and keep available
4171 at all times. When traffic begins to rise above what the existing
4172 processes can handle this many more will be spawned up to the maximum
4173 configured. A minimum setting of 1 is required.
4177 The number of requests each redirector helper can handle in
4178 parallel. Defaults to 0 which indicates the redirector
4179 is a old-style single threaded redirector.
4181 When this directive is set to a value >= 1 then the protocol
4182 used to communicate with the helper is modified to include
4183 a request ID in front of the request/response. The request
4184 ID from the request must be echoed back with the response
4188 NAME: url_rewrite_host_header redirect_rewrites_host_header
4191 LOC: Config.onoff.redir_rewrites_host
4193 To preserve same-origin security policies in browsers and
4194 prevent Host: header forgery by redirectors Squid rewrites
4195 any Host: header in redirected requests.
4197 If you are running an accelerator this may not be a wanted
4198 effect of a redirector. This directive enables you disable
4199 Host: alteration in reverse-proxy traffic.
4201 WARNING: Entries are cached on the result of the URL rewriting
4202 process, so be careful if you have domain-virtual hosts.
4204 WARNING: Squid and other software verifies the URL and Host
4205 are matching, so be careful not to relay through other proxies
4206 or inspecting firewalls with this disabled.
4209 NAME: url_rewrite_access redirector_access
4212 LOC: Config.accessList.redirector
4214 If defined, this access list specifies which requests are
4215 sent to the redirector processes. By default all requests
4218 This clause supports both fast and slow acl types.
4219 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4222 NAME: url_rewrite_bypass redirector_bypass
4224 LOC: Config.onoff.redirector_bypass
4227 When this is 'on', a request will not go through the
4228 redirector if all redirectors are busy. If this is 'off'
4229 and the redirector queue grows too large, Squid will exit
4230 with a FATAL error and ask you to increase the number of
4231 redirectors. You should only enable this if the redirectors
4232 are not critical to your caching system. If you use
4233 redirectors for access control, and you enable this option,
4234 users may have access to pages they should not
4235 be allowed to request.
4239 OPTIONS FOR TUNING THE CACHE
4240 -----------------------------------------------------------------------------
4243 NAME: cache no_cache
4246 LOC: Config.accessList.noCache
4248 A list of ACL elements which, if matched and denied, cause the request to
4249 not be satisfied from the cache and the reply to not be cached.
4250 In other words, use this to force certain objects to never be cached.
4252 You must use the words 'allow' or 'deny' to indicate whether items
4253 matching the ACL should be allowed or denied into the cache.
4255 Default is to allow all to be cached.
4257 This clause supports both fast and slow acl types.
4258 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4264 LOC: Config.maxStale
4267 This option puts an upper limit on how stale content Squid
4268 will serve from the cache if cache validation fails.
4269 Can be overriden by the refresh_pattern max-stale option.
4272 NAME: refresh_pattern
4273 TYPE: refreshpattern
4277 usage: refresh_pattern [-i] regex min percent max [options]
4279 By default, regular expressions are CASE-SENSITIVE. To make
4280 them case-insensitive, use the -i option.
4282 'Min' is the time (in minutes) an object without an explicit
4283 expiry time should be considered fresh. The recommended
4284 value is 0, any higher values may cause dynamic applications
4285 to be erroneously cached unless the application designer
4286 has taken the appropriate actions.
4288 'Percent' is a percentage of the objects age (time since last
4289 modification age) an object without explicit expiry time
4290 will be considered fresh.
4292 'Max' is an upper limit on how long objects without an explicit
4293 expiry time will be considered fresh.
4295 options: override-expire
4300 ignore-must-revalidate
4307 override-expire enforces min age even if the server
4308 sent an explicit expiry time (e.g., with the
4309 Expires: header or Cache-Control: max-age). Doing this
4310 VIOLATES the HTTP standard. Enabling this feature
4311 could make you liable for problems which it causes.
4313 Note: override-expire does not enforce staleness - it only extends
4314 freshness / min. If the server returns a Expires time which
4315 is longer than your max time, Squid will still consider
4316 the object fresh for that period of time.
4318 override-lastmod enforces min age even on objects
4319 that were modified recently.
4321 reload-into-ims changes client no-cache or ``reload''
4322 to If-Modified-Since requests. Doing this VIOLATES the
4323 HTTP standard. Enabling this feature could make you
4324 liable for problems which it causes.
4326 ignore-reload ignores a client no-cache or ``reload''
4327 header. Doing this VIOLATES the HTTP standard. Enabling
4328 this feature could make you liable for problems which
4331 ignore-no-store ignores any ``Cache-control: no-store''
4332 headers received from a server. Doing this VIOLATES
4333 the HTTP standard. Enabling this feature could make you
4334 liable for problems which it causes.
4336 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
4337 headers received from a server. Doing this VIOLATES
4338 the HTTP standard. Enabling this feature could make you
4339 liable for problems which it causes.
4341 ignore-private ignores any ``Cache-control: private''
4342 headers received from a server. Doing this VIOLATES
4343 the HTTP standard. Enabling this feature could make you
4344 liable for problems which it causes.
4346 ignore-auth caches responses to requests with authorization,
4347 as if the originserver had sent ``Cache-control: public''
4348 in the response header. Doing this VIOLATES the HTTP standard.
4349 Enabling this feature could make you liable for problems which
4352 refresh-ims causes squid to contact the origin server
4353 when a client issues an If-Modified-Since request. This
4354 ensures that the client will receive an updated version
4355 if one is available.
4357 store-stale stores responses even if they don't have explicit
4358 freshness or a validator (i.e., Last-Modified or an ETag)
4359 present, or if they're already stale. By default, Squid will
4360 not cache such responses because they usually can't be
4361 reused. Note that such responses will be stale by default.
4363 max-stale=NN provide a maximum staleness factor. Squid won't
4364 serve objects more stale than this even if it failed to
4365 validate the object. Default: use the max_stale global limit.
4367 Basically a cached object is:
4369 FRESH if expires < now, else STALE
4371 FRESH if lm-factor < percent, else STALE
4375 The refresh_pattern lines are checked in the order listed here.
4376 The first entry which matches is used. If none of the entries
4377 match the default will be used.
4379 Note, you must uncomment all the default lines if you want
4380 to change one. The default setting is only active if none is
4385 # Add any of your own refresh_pattern entries above these.
4386 refresh_pattern ^ftp: 1440 20% 10080
4387 refresh_pattern ^gopher: 1440 0% 1440
4388 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
4389 refresh_pattern . 0 20% 4320
4393 NAME: quick_abort_min
4397 LOC: Config.quickAbort.min
4400 NAME: quick_abort_max
4404 LOC: Config.quickAbort.max
4407 NAME: quick_abort_pct
4411 LOC: Config.quickAbort.pct
4413 The cache by default continues downloading aborted requests
4414 which are almost completed (less than 16 KB remaining). This
4415 may be undesirable on slow (e.g. SLIP) links and/or very busy
4416 caches. Impatient users may tie up file descriptors and
4417 bandwidth by repeatedly requesting and immediately aborting
4420 When the user aborts a request, Squid will check the
4421 quick_abort values to the amount of data transfered until
4424 If the transfer has less than 'quick_abort_min' KB remaining,
4425 it will finish the retrieval.
4427 If the transfer has more than 'quick_abort_max' KB remaining,
4428 it will abort the retrieval.
4430 If more than 'quick_abort_pct' of the transfer has completed,
4431 it will finish the retrieval.
4433 If you do not want any retrieval to continue after the client
4434 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
4437 If you want retrievals to always continue if they are being
4438 cached set 'quick_abort_min' to '-1 KB'.
4441 NAME: read_ahead_gap
4442 COMMENT: buffer-size
4444 LOC: Config.readAheadGap
4447 The amount of data the cache will buffer ahead of what has been
4448 sent to the client when retrieving an object from another server.
4452 IFDEF: USE_HTTP_VIOLATIONS
4455 LOC: Config.negativeTtl
4458 Set the Default Time-to-Live (TTL) for failed requests.
4459 Certain types of failures (such as "connection refused" and
4460 "404 Not Found") are able to be negatively-cached for a short time.
4461 Modern web servers should provide Expires: header, however if they
4462 do not this can provide a minimum TTL.
4463 The default is not to cache errors with unknown expiry details.
4465 Note that this is different from negative caching of DNS lookups.
4467 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4468 this feature could make you liable for problems which it
4472 NAME: positive_dns_ttl
4475 LOC: Config.positiveDnsTtl
4478 Upper limit on how long Squid will cache positive DNS responses.
4479 Default is 6 hours (360 minutes). This directive must be set
4480 larger than negative_dns_ttl.
4483 NAME: negative_dns_ttl
4486 LOC: Config.negativeDnsTtl
4489 Time-to-Live (TTL) for negative caching of failed DNS lookups.
4490 This also sets the lower cache limit on positive lookups.
4491 Minimum value is 1 second, and it is not recommendable to go
4492 much below 10 seconds.
4495 NAME: range_offset_limit
4496 COMMENT: size [acl acl...]
4498 LOC: Config.rangeOffsetLimit
4501 usage: (size) [units] [[!]aclname]
4503 Sets an upper limit on how far (number of bytes) into the file
4504 a Range request may be to cause Squid to prefetch the whole file.
4505 If beyond this limit, Squid forwards the Range request as it is and
4506 the result is NOT cached.
4508 This is to stop a far ahead range request (lets say start at 17MB)
4509 from making Squid fetch the whole object up to that point before
4510 sending anything to the client.
4512 Multiple range_offset_limit lines may be specified, and they will
4513 be searched from top to bottom on each request until a match is found.
4514 The first match found will be used. If no line matches a request, the
4515 default limit of 0 bytes will be used.
4517 'size' is the limit specified as a number of units.
4519 'units' specifies whether to use bytes, KB, MB, etc.
4520 If no units are specified bytes are assumed.
4522 A size of 0 causes Squid to never fetch more than the
4523 client requested. (default)
4525 A size of 'none' causes Squid to always fetch the object from the
4526 beginning so it may cache the result. (2.0 style)
4528 'aclname' is the name of a defined ACL.
4530 NP: Using 'none' as the byte value here will override any quick_abort settings
4531 that may otherwise apply to the range request. The range request will
4532 be fully fetched from start to finish regardless of the client
4533 actions. This affects bandwidth usage.
4536 NAME: minimum_expiry_time
4539 LOC: Config.minimum_expiry_time
4542 The minimum caching time according to (Expires - Date)
4543 Headers Squid honors if the object can't be revalidated
4544 defaults to 60 seconds. In reverse proxy environments it
4545 might be desirable to honor shorter object lifetimes. It
4546 is most likely better to make your server return a
4547 meaningful Last-Modified header however. In ESI environments
4548 where page fragments often have short lifetimes, this will
4549 often be best set to 0.
4552 NAME: store_avg_object_size
4556 LOC: Config.Store.avgObjectSize
4558 Average object size, used to estimate number of objects your
4559 cache can hold. The default is 13 KB.
4562 NAME: store_objects_per_bucket
4565 LOC: Config.Store.objectsPerBucket
4567 Target number of objects per bucket in the store hash table.
4568 Lowering this value increases the total number of buckets and
4569 also the storage maintenance rate. The default is 20.
4574 -----------------------------------------------------------------------------
4577 NAME: request_header_max_size
4581 LOC: Config.maxRequestHeaderSize
4583 This specifies the maximum size for HTTP headers in a request.
4584 Request headers are usually relatively small (about 512 bytes).
4585 Placing a limit on the request header size will catch certain
4586 bugs (for example with persistent connections) and possibly
4587 buffer-overflow or denial-of-service attacks.
4590 NAME: reply_header_max_size
4594 LOC: Config.maxReplyHeaderSize
4596 This specifies the maximum size for HTTP headers in a reply.
4597 Reply headers are usually relatively small (about 512 bytes).
4598 Placing a limit on the reply header size will catch certain
4599 bugs (for example with persistent connections) and possibly
4600 buffer-overflow or denial-of-service attacks.
4603 NAME: request_body_max_size
4607 LOC: Config.maxRequestBodySize
4609 This specifies the maximum size for an HTTP request body.
4610 In other words, the maximum size of a PUT/POST request.
4611 A user who attempts to send a request with a body larger
4612 than this limit receives an "Invalid Request" error message.
4613 If you set this parameter to a zero (the default), there will
4614 be no limit imposed.
4617 NAME: client_request_buffer_max_size
4621 LOC: Config.maxRequestBufferSize
4623 This specifies the maximum buffer size of a client request.
4624 It prevents squid eating too much memory when somebody uploads
4628 NAME: chunked_request_body_max_size
4632 LOC: Config.maxChunkedRequestBodySize
4634 A broken or confused HTTP/1.1 client may send a chunked HTTP
4635 request to Squid. Squid does not have full support for that
4636 feature yet. To cope with such requests, Squid buffers the
4637 entire request and then dechunks request body to create a
4638 plain HTTP/1.0 request with a known content length. The plain
4639 request is then used by the rest of Squid code as usual.
4641 The option value specifies the maximum size of the buffer used
4642 to hold the request before the conversion. If the chunked
4643 request size exceeds the specified limit, the conversion
4644 fails, and the client receives an "unsupported request" error,
4645 as if dechunking was disabled.
4647 Dechunking is enabled by default. To disable conversion of
4648 chunked requests, set the maximum to zero.
4650 Request dechunking feature and this option in particular are a
4651 temporary hack. When chunking requests and responses are fully
4652 supported, there will be no need to buffer a chunked request.
4656 IFDEF: USE_HTTP_VIOLATIONS
4659 LOC: Config.accessList.brokenPosts
4661 A list of ACL elements which, if matched, causes Squid to send
4662 an extra CRLF pair after the body of a PUT/POST request.
4664 Some HTTP servers has broken implementations of PUT/POST,
4665 and rely on an extra CRLF pair sent by some WWW clients.
4667 Quote from RFC2616 section 4.1 on this matter:
4669 Note: certain buggy HTTP/1.0 client implementations generate an
4670 extra CRLF's after a POST request. To restate what is explicitly
4671 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
4672 a request with an extra CRLF.
4674 This clause only supports fast acl types.
4675 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4678 acl buggy_server url_regex ^http://....
4679 broken_posts allow buggy_server
4682 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
4685 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
4687 LOC: Adaptation::Config::use_indirect_client
4689 Controls whether the indirect client IP address (instead of the direct
4690 client IP address) is passed to adaptation services.
4692 See also: follow_x_forwarded_for adaptation_send_client_ip
4696 IFDEF: USE_HTTP_VIOLATIONS
4700 LOC: Config.onoff.via
4702 If set (default), Squid will include a Via header in requests and
4703 replies as required by RFC2616.
4709 LOC: Config.onoff.ie_refresh
4712 Microsoft Internet Explorer up until version 5.5 Service
4713 Pack 1 has an issue with transparent proxies, wherein it
4714 is impossible to force a refresh. Turning this on provides
4715 a partial fix to the problem, by causing all IMS-REFRESH
4716 requests from older IE versions to check the origin server
4717 for fresh content. This reduces hit ratio by some amount
4718 (~10% in my experience), but allows users to actually get
4719 fresh content when they want it. Note because Squid
4720 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
4721 of 5.5 is unchanged from old versions of Squid (i.e. a
4722 forced refresh is impossible). Newer versions of IE will,
4723 hopefully, continue to have the new behavior and will be
4724 handled based on that assumption. This option defaults to
4725 the old Squid behavior, which is better for hit ratios but
4726 worse for clients using IE, if they need to be able to
4727 force fresh content.
4730 NAME: vary_ignore_expire
4733 LOC: Config.onoff.vary_ignore_expire
4736 Many HTTP servers supporting Vary gives such objects
4737 immediate expiry time with no cache-control header
4738 when requested by a HTTP/1.0 client. This option
4739 enables Squid to ignore such expiry times until
4740 HTTP/1.1 is fully implemented.
4742 WARNING: If turned on this may eventually cause some
4743 varying objects not intended for caching to get cached.
4746 NAME: request_entities
4748 LOC: Config.onoff.request_entities
4751 Squid defaults to deny GET and HEAD requests with request entities,
4752 as the meaning of such requests are undefined in the HTTP standard
4753 even if not explicitly forbidden.
4755 Set this directive to on if you have clients which insists
4756 on sending request entities in GET or HEAD requests. But be warned
4757 that there is server software (both proxies and web servers) which
4758 can fail to properly process this kind of request which may make you
4759 vulnerable to cache pollution attacks if enabled.
4762 NAME: request_header_access
4763 IFDEF: USE_HTTP_VIOLATIONS
4764 TYPE: http_header_access
4765 LOC: Config.request_header_access
4768 Usage: request_header_access header_name allow|deny [!]aclname ...
4770 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4771 this feature could make you liable for problems which it
4774 This option replaces the old 'anonymize_headers' and the
4775 older 'http_anonymizer' option with something that is much
4776 more configurable. A list of ACLs for each header name allows
4777 removal of specific header fields under specific conditions.
4779 This option only applies to outgoing HTTP request headers (i.e.,
4780 headers sent by Squid to the next HTTP hop such as a cache peer
4781 or an origin server). The option has no effect during cache hit
4782 detection. The equivalent adaptation vectoring point in ICAP
4783 terminology is post-cache REQMOD.
4785 The option is applied to individual outgoing request header
4786 fields. For each request header field F, Squid uses the first
4787 qualifying sets of request_header_access rules:
4789 1. Rules with header_name equal to F's name.
4790 2. Rules with header_name 'Other', provided F's name is not
4791 on the hard-coded list of commonly used HTTP header names.
4792 3. Rules with header_name 'All'.
4794 Within that qualifying rule set, rule ACLs are checked as usual.
4795 If ACLs of an "allow" rule match, the header field is allowed to
4796 go through as is. If ACLs of a "deny" rule match, the header is
4797 removed and request_header_replace is then checked to identify
4798 if the removed header has a replacement. If no rules within the
4799 set have matching ACLs, the header field is left as is.
4801 For example, to achieve the same behavior as the old
4802 'http_anonymizer standard' option, you should use:
4804 request_header_access From deny all
4805 request_header_access Referer deny all
4806 request_header_access Server deny all
4807 request_header_access User-Agent deny all
4808 request_header_access WWW-Authenticate deny all
4809 request_header_access Link deny all
4811 Or, to reproduce the old 'http_anonymizer paranoid' feature
4814 request_header_access Allow allow all
4815 request_header_access Authorization allow all
4816 request_header_access WWW-Authenticate allow all
4817 request_header_access Proxy-Authorization allow all
4818 request_header_access Proxy-Authenticate allow all
4819 request_header_access Cache-Control allow all
4820 request_header_access Content-Encoding allow all
4821 request_header_access Content-Length allow all
4822 request_header_access Content-Type allow all
4823 request_header_access Date allow all
4824 request_header_access Expires allow all
4825 request_header_access Host allow all
4826 request_header_access If-Modified-Since allow all
4827 request_header_access Last-Modified allow all
4828 request_header_access Location allow all
4829 request_header_access Pragma allow all
4830 request_header_access Accept allow all
4831 request_header_access Accept-Charset allow all
4832 request_header_access Accept-Encoding allow all
4833 request_header_access Accept-Language allow all
4834 request_header_access Content-Language allow all
4835 request_header_access Mime-Version allow all
4836 request_header_access Retry-After allow all
4837 request_header_access Title allow all
4838 request_header_access Connection allow all
4839 request_header_access All deny all
4841 although many of those are HTTP reply headers, and so should be
4842 controlled with the reply_header_access directive.
4844 By default, all headers are allowed (no anonymizing is
4848 NAME: reply_header_access
4849 IFDEF: USE_HTTP_VIOLATIONS
4850 TYPE: http_header_access
4851 LOC: Config.reply_header_access
4854 Usage: reply_header_access header_name allow|deny [!]aclname ...
4856 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4857 this feature could make you liable for problems which it
4860 This option only applies to reply headers, i.e., from the
4861 server to the client.
4863 This is the same as request_header_access, but in the other
4864 direction. Please see request_header_access for detailed
4867 For example, to achieve the same behavior as the old
4868 'http_anonymizer standard' option, you should use:
4870 reply_header_access From deny all
4871 reply_header_access Referer deny all
4872 reply_header_access Server deny all
4873 reply_header_access User-Agent deny all
4874 reply_header_access WWW-Authenticate deny all
4875 reply_header_access Link deny all
4877 Or, to reproduce the old 'http_anonymizer paranoid' feature
4880 reply_header_access Allow allow all
4881 reply_header_access Authorization allow all
4882 reply_header_access WWW-Authenticate allow all
4883 reply_header_access Proxy-Authorization allow all
4884 reply_header_access Proxy-Authenticate allow all
4885 reply_header_access Cache-Control allow all
4886 reply_header_access Content-Encoding allow all
4887 reply_header_access Content-Length allow all
4888 reply_header_access Content-Type allow all
4889 reply_header_access Date allow all
4890 reply_header_access Expires allow all
4891 reply_header_access Host allow all
4892 reply_header_access If-Modified-Since allow all
4893 reply_header_access Last-Modified allow all
4894 reply_header_access Location allow all
4895 reply_header_access Pragma allow all
4896 reply_header_access Accept allow all
4897 reply_header_access Accept-Charset allow all
4898 reply_header_access Accept-Encoding allow all
4899 reply_header_access Accept-Language allow all
4900 reply_header_access Content-Language allow all
4901 reply_header_access Mime-Version allow all
4902 reply_header_access Retry-After allow all
4903 reply_header_access Title allow all
4904 reply_header_access Connection allow all
4905 reply_header_access All deny all
4907 although the HTTP request headers won't be usefully controlled
4908 by this directive -- see request_header_access for details.
4910 By default, all headers are allowed (no anonymizing is
4914 NAME: request_header_replace header_replace
4915 IFDEF: USE_HTTP_VIOLATIONS
4916 TYPE: http_header_replace
4917 LOC: Config.request_header_access
4920 Usage: request_header_replace header_name message
4921 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
4923 This option allows you to change the contents of headers
4924 denied with request_header_access above, by replacing them
4925 with some fixed string. This replaces the old fake_user_agent
4928 This only applies to request headers, not reply headers.
4930 By default, headers are removed if denied.
4933 NAME: reply_header_replace
4934 IFDEF: USE_HTTP_VIOLATIONS
4935 TYPE: http_header_replace
4936 LOC: Config.reply_header_access
4939 Usage: reply_header_replace header_name message
4940 Example: reply_header_replace Server Foo/1.0
4942 This option allows you to change the contents of headers
4943 denied with reply_header_access above, by replacing them
4944 with some fixed string.
4946 This only applies to reply headers, not request headers.
4948 By default, headers are removed if denied.
4951 NAME: request_header_add
4952 TYPE: HeaderWithAclList
4953 LOC: Config.request_header_add
4956 Usage: request_header_add field-name field-value acl1 [acl2] ...
4957 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
4959 This option adds header fields to outgoing HTTP requests (i.e.,
4960 request headers sent by Squid to the next HTTP hop such as a
4961 cache peer or an origin server). The option has no effect during
4962 cache hit detection. The equivalent adaptation vectoring point
4963 in ICAP terminology is post-cache REQMOD.
4965 Field-name is a token specifying an HTTP header name. If a
4966 standard HTTP header name is used, Squid does not check whether
4967 the new header conflicts with any existing headers or violates
4968 HTTP rules. If the request to be modified already contains a
4969 field with the same name, the old field is preserved but the
4970 header field values are not merged.
4972 Field-value is either a token or a quoted string. If quoted
4973 string format is used, then the surrounding quotes are removed
4974 while escape sequences and %macros are processed.
4976 In theory, all of the logformat codes can be used as %macros.
4977 However, unlike logging (which happens at the very end of
4978 transaction lifetime), the transaction may not yet have enough
4979 information to expand a macro when the new header value is needed.
4980 And some information may already be available to Squid but not yet
4981 committed where the macro expansion code can access it (report
4982 such instances!). The macro will be expanded into a single dash
4983 ('-') in such cases. Not all macros have been tested.
4985 One or more Squid ACLs may be specified to restrict header
4986 injection to matching requests. As always in squid.conf, all
4987 ACLs in an option ACL list must be satisfied for the insertion
4988 to happen. The request_header_add option supports fast ACLs
4997 This option used to log custom information about the master
4998 transaction. For example, an admin may configure Squid to log
4999 which "user group" the transaction belongs to, where "user group"
5000 will be determined based on a set of ACLs and not [just]
5001 authentication information.
5002 Values of key/value pairs can be logged using %{key}note macros:
5004 note key value acl ...
5005 logformat myFormat ... %{key}note ...
5008 NAME: relaxed_header_parser
5009 COMMENT: on|off|warn
5011 LOC: Config.onoff.relaxed_header_parser
5014 In the default "on" setting Squid accepts certain forms
5015 of non-compliant HTTP messages where it is unambiguous
5016 what the sending application intended even if the message
5017 is not correctly formatted. The messages is then normalized
5018 to the correct form when forwarded by Squid.
5020 If set to "warn" then a warning will be emitted in cache.log
5021 each time such HTTP error is encountered.
5023 If set to "off" then such HTTP errors will cause the request
5024 or response to be rejected.
5029 -----------------------------------------------------------------------------
5032 NAME: forward_timeout
5035 LOC: Config.Timeout.forward
5038 This parameter specifies how long Squid should at most attempt in
5039 finding a forwarding path for the request before giving up.
5042 NAME: connect_timeout
5045 LOC: Config.Timeout.connect
5048 This parameter specifies how long to wait for the TCP connect to
5049 the requested server or peer to complete before Squid should
5050 attempt to find another path where to forward the request.
5053 NAME: peer_connect_timeout
5056 LOC: Config.Timeout.peer_connect
5059 This parameter specifies how long to wait for a pending TCP
5060 connection to a peer cache. The default is 30 seconds. You
5061 may also set different timeout values for individual neighbors
5062 with the 'connect-timeout' option on a 'cache_peer' line.
5068 LOC: Config.Timeout.read
5071 The read_timeout is applied on server-side connections. After
5072 each successful read(), the timeout will be extended by this
5073 amount. If no data is read again after this amount of time,
5074 the request is aborted and logged with ERR_READ_TIMEOUT. The
5075 default is 15 minutes.
5081 LOC: Config.Timeout.write
5084 This timeout is tracked for all connections that have data
5085 available for writing and are waiting for the socket to become
5086 ready. After each successful write, the timeout is extended by
5087 the configured amount. If Squid has data to write but the
5088 connection is not ready for the configured duration, the
5089 transaction associated with the connection is terminated. The
5090 default is 15 minutes.
5093 NAME: request_timeout
5095 LOC: Config.Timeout.request
5098 How long to wait for complete HTTP request headers after initial
5099 connection establishment.
5102 NAME: client_idle_pconn_timeout persistent_request_timeout
5104 LOC: Config.Timeout.clientIdlePconn
5107 How long to wait for the next HTTP request on a persistent
5108 client connection after the previous request completes.
5111 NAME: client_lifetime
5114 LOC: Config.Timeout.lifetime
5117 The maximum amount of time a client (browser) is allowed to
5118 remain connected to the cache process. This protects the Cache
5119 from having a lot of sockets (and hence file descriptors) tied up
5120 in a CLOSE_WAIT state from remote clients that go away without
5121 properly shutting down (either because of a network failure or
5122 because of a poor client implementation). The default is one
5125 NOTE: The default value is intended to be much larger than any
5126 client would ever need to be connected to your cache. You
5127 should probably change client_lifetime only as a last resort.
5128 If you seem to have many client connections tying up
5129 filedescriptors, we recommend first tuning the read_timeout,
5130 request_timeout, persistent_request_timeout and quick_abort values.
5133 NAME: half_closed_clients
5135 LOC: Config.onoff.half_closed_clients
5138 Some clients may shutdown the sending side of their TCP
5139 connections, while leaving their receiving sides open. Sometimes,
5140 Squid can not tell the difference between a half-closed and a
5141 fully-closed TCP connection.
5143 By default, Squid will immediately close client connections when
5144 read(2) returns "no more data to read."
5146 Change this option to 'on' and Squid will keep open connections
5147 until a read(2) or write(2) on the socket returns an error.
5148 This may show some benefits for reverse proxies. But if not
5149 it is recommended to leave OFF.
5152 NAME: server_idle_pconn_timeout pconn_timeout
5154 LOC: Config.Timeout.serverIdlePconn
5157 Timeout for idle persistent connections to servers and other
5164 LOC: Ident::TheConfig.timeout
5167 Maximum time to wait for IDENT lookups to complete.
5169 If this is too high, and you enabled IDENT lookups from untrusted
5170 users, you might be susceptible to denial-of-service by having
5171 many ident requests going at once.
5174 NAME: shutdown_lifetime
5177 LOC: Config.shutdownLifetime
5180 When SIGTERM or SIGHUP is received, the cache is put into
5181 "shutdown pending" mode until all active sockets are closed.
5182 This value is the lifetime to set for all open descriptors
5183 during shutdown mode. Any active clients after this many
5184 seconds will receive a 'timeout' message.
5188 ADMINISTRATIVE PARAMETERS
5189 -----------------------------------------------------------------------------
5195 LOC: Config.adminEmail
5197 Email-address of local cache manager who will receive
5198 mail if the cache dies. The default is "webmaster."
5204 LOC: Config.EmailFrom
5206 From: email-address for mail sent when the cache dies.
5207 The default is to use 'appname@unique_hostname'.
5208 Default appname value is "squid", can be changed into
5209 src/globals.h before building squid.
5215 LOC: Config.EmailProgram
5217 Email program used to send mail if the cache dies.
5218 The default is "mail". The specified program must comply
5219 with the standard Unix mail syntax:
5220 mail-program recipient < mailfile
5222 Optional command line options can be specified.
5225 NAME: cache_effective_user
5227 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
5228 LOC: Config.effectiveUser
5230 If you start Squid as root, it will change its effective/real
5231 UID/GID to the user specified below. The default is to change
5232 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
5233 see also; cache_effective_group
5236 NAME: cache_effective_group
5239 LOC: Config.effectiveGroup
5241 Squid sets the GID to the effective user's default group ID
5242 (taken from the password file) and supplementary group list
5243 from the groups membership.
5245 If you want Squid to run with a specific GID regardless of
5246 the group memberships of the effective user then set this
5247 to the group (or GID) you want Squid to run as. When set
5248 all other group privileges of the effective user are ignored
5249 and only this GID is effective. If Squid is not started as
5250 root the user starting Squid MUST be member of the specified
5253 This option is not recommended by the Squid Team.
5254 Our preference is for administrators to configure a secure
5255 user account for squid with UID/GID matching system policies.
5258 NAME: httpd_suppress_version_string
5262 LOC: Config.onoff.httpd_suppress_version_string
5264 Suppress Squid version string info in HTTP headers and HTML error pages.
5267 NAME: visible_hostname
5269 LOC: Config.visibleHostname
5272 If you want to present a special hostname in error messages, etc,
5273 define this. Otherwise, the return value of gethostname()
5274 will be used. If you have multiple caches in a cluster and
5275 get errors about IP-forwarding you must set them to have individual
5276 names with this setting.
5279 NAME: unique_hostname
5281 LOC: Config.uniqueHostname
5284 If you want to have multiple machines with the same
5285 'visible_hostname' you must give each machine a different
5286 'unique_hostname' so forwarding loops can be detected.
5289 NAME: hostname_aliases
5291 LOC: Config.hostnameAliases
5294 A list of other DNS names your cache has.
5302 Minimum umask which should be enforced while the proxy
5303 is running, in addition to the umask set at startup.
5305 For a traditional octal representation of umasks, start
5310 OPTIONS FOR THE CACHE REGISTRATION SERVICE
5311 -----------------------------------------------------------------------------
5313 This section contains parameters for the (optional) cache
5314 announcement service. This service is provided to help
5315 cache administrators locate one another in order to join or
5316 create cache hierarchies.
5318 An 'announcement' message is sent (via UDP) to the registration
5319 service by Squid. By default, the announcement message is NOT
5320 SENT unless you enable it with 'announce_period' below.
5322 The announcement message includes your hostname, plus the
5323 following information from this configuration file:
5329 All current information is processed regularly and made
5330 available on the Web at http://www.ircache.net/Cache/Tracker/.
5333 NAME: announce_period
5335 LOC: Config.Announce.period
5338 This is how frequently to send cache announcements. The
5339 default is `0' which disables sending the announcement
5342 To enable announcing your cache, just set an announce period.
5345 announce_period 1 day
5350 DEFAULT: tracker.ircache.net
5351 LOC: Config.Announce.host
5357 LOC: Config.Announce.file
5363 LOC: Config.Announce.port
5365 announce_host and announce_port set the hostname and port
5366 number where the registration message will be sent.
5368 Hostname will default to 'tracker.ircache.net' and port will
5369 default default to 3131. If the 'filename' argument is given,
5370 the contents of that file will be included in the announce
5375 HTTPD-ACCELERATOR OPTIONS
5376 -----------------------------------------------------------------------------
5379 NAME: httpd_accel_surrogate_id
5382 LOC: Config.Accel.surrogate_id
5384 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
5385 need an identification token to allow control targeting. Because
5386 a farm of surrogates may all perform the same tasks, they may share
5387 an identification token.
5389 The default ID is the visible_hostname
5392 NAME: http_accel_surrogate_remote
5396 LOC: Config.onoff.surrogate_is_remote
5398 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
5399 Set this to on to have squid behave as a remote surrogate.
5403 IFDEF: USE_SQUID_ESI
5404 COMMENT: libxml2|expat|custom
5406 LOC: ESIParser::Type
5409 ESI markup is not strictly XML compatible. The custom ESI parser
5410 will give higher performance, but cannot handle non ASCII character
5415 DELAY POOL PARAMETERS
5416 -----------------------------------------------------------------------------
5420 TYPE: delay_pool_count
5422 IFDEF: USE_DELAY_POOLS
5425 This represents the number of delay pools to be used. For example,
5426 if you have one class 2 delay pool and one class 3 delays pool, you
5427 have a total of 2 delay pools.
5431 TYPE: delay_pool_class
5433 IFDEF: USE_DELAY_POOLS
5436 This defines the class of each delay pool. There must be exactly one
5437 delay_class line for each delay pool. For example, to define two
5438 delay pools, one of class 2 and one of class 3, the settings above
5442 delay_pools 4 # 4 delay pools
5443 delay_class 1 2 # pool 1 is a class 2 pool
5444 delay_class 2 3 # pool 2 is a class 3 pool
5445 delay_class 3 4 # pool 3 is a class 4 pool
5446 delay_class 4 5 # pool 4 is a class 5 pool
5448 The delay pool classes are:
5450 class 1 Everything is limited by a single aggregate
5453 class 2 Everything is limited by a single aggregate
5454 bucket as well as an "individual" bucket chosen
5455 from bits 25 through 32 of the IPv4 address.
5457 class 3 Everything is limited by a single aggregate
5458 bucket as well as a "network" bucket chosen
5459 from bits 17 through 24 of the IP address and a
5460 "individual" bucket chosen from bits 17 through
5461 32 of the IPv4 address.
5463 class 4 Everything in a class 3 delay pool, with an
5464 additional limit on a per user basis. This
5465 only takes effect if the username is established
5466 in advance - by forcing authentication in your
5469 class 5 Requests are grouped according their tag (see
5470 external_acl's tag= reply).
5473 Each pool also requires a delay_parameters directive to configure the pool size
5474 and speed limits used whenever the pool is applied to a request. Along with
5475 a set of delay_access directives to determine when it is used.
5477 NOTE: If an IP address is a.b.c.d
5478 -> bits 25 through 32 are "d"
5479 -> bits 17 through 24 are "c"
5480 -> bits 17 through 32 are "c * 256 + d"
5482 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
5483 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
5487 TYPE: delay_pool_access
5489 IFDEF: USE_DELAY_POOLS
5492 This is used to determine which delay pool a request falls into.
5494 delay_access is sorted per pool and the matching starts with pool 1,
5495 then pool 2, ..., and finally pool N. The first delay pool where the
5496 request is allowed is selected for the request. If it does not allow
5497 the request to any pool then the request is not delayed (default).
5499 For example, if you want some_big_clients in delay
5500 pool 1 and lotsa_little_clients in delay pool 2:
5503 delay_access 1 allow some_big_clients
5504 delay_access 1 deny all
5505 delay_access 2 allow lotsa_little_clients
5506 delay_access 2 deny all
5507 delay_access 3 allow authenticated_clients
5510 NAME: delay_parameters
5511 TYPE: delay_pool_rates
5513 IFDEF: USE_DELAY_POOLS
5516 This defines the parameters for a delay pool. Each delay pool has
5517 a number of "buckets" associated with it, as explained in the
5518 description of delay_class.
5520 For a class 1 delay pool, the syntax is:
5522 delay_parameters pool aggregate
5524 For a class 2 delay pool:
5526 delay_parameters pool aggregate individual
5528 For a class 3 delay pool:
5530 delay_parameters pool aggregate network individual
5532 For a class 4 delay pool:
5534 delay_parameters pool aggregate network individual user
5536 For a class 5 delay pool:
5538 delay_parameters pool tagrate
5540 The option variables are:
5542 pool a pool number - ie, a number between 1 and the
5543 number specified in delay_pools as used in
5546 aggregate the speed limit parameters for the aggregate bucket
5549 individual the speed limit parameters for the individual
5550 buckets (class 2, 3).
5552 network the speed limit parameters for the network buckets
5555 user the speed limit parameters for the user buckets
5558 tagrate the speed limit parameters for the tag buckets
5561 A pair of delay parameters is written restore/maximum, where restore is
5562 the number of bytes (not bits - modem and network speeds are usually
5563 quoted in bits) per second placed into the bucket, and maximum is the
5564 maximum number of bytes which can be in the bucket at any time.
5566 There must be one delay_parameters line for each delay pool.
5569 For example, if delay pool number 1 is a class 2 delay pool as in the
5570 above example, and is being used to strictly limit each host to 64Kbit/sec
5571 (plus overheads), with no overall limit, the line is:
5573 delay_parameters 1 -1/-1 8000/8000
5575 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
5577 Note that the figure -1 is used to represent "unlimited".
5580 And, if delay pool number 2 is a class 3 delay pool as in the above
5581 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
5582 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
5583 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
5584 to permit a decent web page to be downloaded at a decent speed
5585 (if the network is not being limited due to overuse) but slow down
5586 large downloads more significantly:
5588 delay_parameters 2 32000/32000 8000/8000 600/8000
5590 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
5591 8 x 8000 KByte/sec -> 64Kbit/sec.
5592 8 x 600 Byte/sec -> 4800bit/sec.
5595 Finally, for a class 4 delay pool as in the example - each user will
5596 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
5598 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
5601 NAME: delay_initial_bucket_level
5602 COMMENT: (percent, 0-100)
5605 IFDEF: USE_DELAY_POOLS
5606 LOC: Config.Delay.initial
5608 The initial bucket percentage is used to determine how much is put
5609 in each bucket when squid starts, is reconfigured, or first notices
5610 a host accessing it (in class 2 and class 3, individual hosts and
5611 networks only have buckets associated with them once they have been
5616 CLIENT DELAY POOL PARAMETERS
5617 -----------------------------------------------------------------------------
5620 NAME: client_delay_pools
5621 TYPE: client_delay_pool_count
5623 IFDEF: USE_DELAY_POOLS
5624 LOC: Config.ClientDelay
5626 This option specifies the number of client delay pools used. It must
5627 preceed other client_delay_* options.
5630 client_delay_pools 2
5633 NAME: client_delay_initial_bucket_level
5634 COMMENT: (percent, 0-no_limit)
5637 IFDEF: USE_DELAY_POOLS
5638 LOC: Config.ClientDelay.initial
5640 This option determines the initial bucket size as a percentage of
5641 max_bucket_size from client_delay_parameters. Buckets are created
5642 at the time of the "first" connection from the matching IP. Idle
5643 buckets are periodically deleted up.
5645 You can specify more than 100 percent but note that such "oversized"
5646 buckets are not refilled until their size goes down to max_bucket_size
5647 from client_delay_parameters.
5650 client_delay_initial_bucket_level 50
5653 NAME: client_delay_parameters
5654 TYPE: client_delay_pool_rates
5656 IFDEF: USE_DELAY_POOLS
5657 LOC: Config.ClientDelay
5660 This option configures client-side bandwidth limits using the
5663 client_delay_parameters pool speed_limit max_bucket_size
5665 pool is an integer ID used for client_delay_access matching.
5667 speed_limit is bytes added to the bucket per second.
5669 max_bucket_size is the maximum size of a bucket, enforced after any
5670 speed_limit additions.
5672 Please see the delay_parameters option for more information and
5676 client_delay_parameters 1 1024 2048
5677 client_delay_parameters 2 51200 16384
5680 NAME: client_delay_access
5681 TYPE: client_delay_pool_access
5683 IFDEF: USE_DELAY_POOLS
5684 LOC: Config.ClientDelay
5687 This option determines the client-side delay pool for the
5690 client_delay_access pool_ID allow|deny acl_name
5692 All client_delay_access options are checked in their pool ID
5693 order, starting with pool 1. The first checked pool with allowed
5694 request is selected for the request. If no ACL matches or there
5695 are no client_delay_access options, the request bandwidth is not
5698 The ACL-selected pool is then used to find the
5699 client_delay_parameters for the request. Client-side pools are
5700 not used to aggregate clients. Clients are always aggregated
5701 based on their source IP addresses (one bucket per source IP).
5703 Please see delay_access for more examples.
5706 client_delay_access 1 allow low_rate_network
5707 client_delay_access 2 allow vips_network
5711 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
5712 -----------------------------------------------------------------------------
5717 LOC: Config.Wccp.router
5721 Use this option to define your WCCP ``home'' router for
5724 wccp_router supports a single WCCP(v1) router
5726 wccp2_router supports multiple WCCPv2 routers
5728 only one of the two may be used at the same time and defines
5729 which version of WCCP to use.
5733 TYPE: IpAddress_list
5734 LOC: Config.Wccp2.router
5738 Use this option to define your WCCP ``home'' router for
5741 wccp_router supports a single WCCP(v1) router
5743 wccp2_router supports multiple WCCPv2 routers
5745 only one of the two may be used at the same time and defines
5746 which version of WCCP to use.
5751 LOC: Config.Wccp.version
5755 This directive is only relevant if you need to set up WCCP(v1)
5756 to some very old and end-of-life Cisco routers. In all other
5757 setups it must be left unset or at the default setting.
5758 It defines an internal version in the WCCP(v1) protocol,
5759 with version 4 being the officially documented protocol.
5761 According to some users, Cisco IOS 11.2 and earlier only
5762 support WCCP version 3. If you're using that or an earlier
5763 version of IOS, you may need to change this value to 3, otherwise
5764 do not specify this parameter.
5767 NAME: wccp2_rebuild_wait
5769 LOC: Config.Wccp2.rebuildwait
5773 If this is enabled Squid will wait for the cache dir rebuild to finish
5774 before sending the first wccp2 HereIAm packet
5777 NAME: wccp2_forwarding_method
5779 LOC: Config.Wccp2.forwarding_method
5783 WCCP2 allows the setting of forwarding methods between the
5784 router/switch and the cache. Valid values are as follows:
5786 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5787 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5789 Currently (as of IOS 12.4) cisco routers only support GRE.
5790 Cisco switches only support the L2 redirect assignment method.
5793 NAME: wccp2_return_method
5795 LOC: Config.Wccp2.return_method
5799 WCCP2 allows the setting of return methods between the
5800 router/switch and the cache for packets that the cache
5801 decides not to handle. Valid values are as follows:
5803 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5804 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5806 Currently (as of IOS 12.4) cisco routers only support GRE.
5807 Cisco switches only support the L2 redirect assignment.
5809 If the "ip wccp redirect exclude in" command has been
5810 enabled on the cache interface, then it is still safe for
5811 the proxy server to use a l2 redirect method even if this
5812 option is set to GRE.
5815 NAME: wccp2_assignment_method
5817 LOC: Config.Wccp2.assignment_method
5821 WCCP2 allows the setting of methods to assign the WCCP hash
5822 Valid values are as follows:
5824 hash - Hash assignment
5825 mask - Mask assignment
5827 As a general rule, cisco routers support the hash assignment method
5828 and cisco switches support the mask assignment method.
5833 LOC: Config.Wccp2.info
5834 DEFAULT_IF_NONE: standard 0
5837 WCCP2 allows for multiple traffic services. There are two
5838 types: "standard" and "dynamic". The standard type defines
5839 one service id - http (id 0). The dynamic service ids can be from
5840 51 to 255 inclusive. In order to use a dynamic service id
5841 one must define the type of traffic to be redirected; this is done
5842 using the wccp2_service_info option.
5844 The "standard" type does not require a wccp2_service_info option,
5845 just specifying the service id will suffice.
5847 MD5 service authentication can be enabled by adding
5848 "password=<password>" to the end of this service declaration.
5852 wccp2_service standard 0 # for the 'web-cache' standard service
5853 wccp2_service dynamic 80 # a dynamic service type which will be
5854 # fleshed out with subsequent options.
5855 wccp2_service standard 0 password=foo
5858 NAME: wccp2_service_info
5859 TYPE: wccp2_service_info
5860 LOC: Config.Wccp2.info
5864 Dynamic WCCPv2 services require further information to define the
5865 traffic you wish to have diverted.
5869 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
5870 priority=<priority> ports=<port>,<port>..
5872 The relevant WCCPv2 flags:
5873 + src_ip_hash, dst_ip_hash
5874 + source_port_hash, dst_port_hash
5875 + src_ip_alt_hash, dst_ip_alt_hash
5876 + src_port_alt_hash, dst_port_alt_hash
5879 The port list can be one to eight entries.
5883 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
5884 priority=240 ports=80
5886 Note: the service id must have been defined by a previous
5887 'wccp2_service dynamic <id>' entry.
5892 LOC: Config.Wccp2.weight
5896 Each cache server gets assigned a set of the destination
5897 hash proportional to their weight.
5902 LOC: Config.Wccp.address
5909 LOC: Config.Wccp2.address
5913 Use this option if you require WCCP to use a specific
5916 The default behavior is to not bind to any specific address.
5920 PERSISTENT CONNECTION HANDLING
5921 -----------------------------------------------------------------------------
5923 Also see "pconn_timeout" in the TIMEOUTS section
5926 NAME: client_persistent_connections
5928 LOC: Config.onoff.client_pconns
5932 NAME: server_persistent_connections
5934 LOC: Config.onoff.server_pconns
5937 Persistent connection support for clients and servers. By
5938 default, Squid uses persistent connections (when allowed)
5939 with its clients and servers. You can use these options to
5940 disable persistent connections with clients and/or servers.
5943 NAME: persistent_connection_after_error
5945 LOC: Config.onoff.error_pconns
5948 With this directive the use of persistent connections after
5949 HTTP errors can be disabled. Useful if you have clients
5950 who fail to handle errors on persistent connections proper.
5953 NAME: detect_broken_pconn
5955 LOC: Config.onoff.detect_broken_server_pconns
5958 Some servers have been found to incorrectly signal the use
5959 of HTTP/1.0 persistent connections even on replies not
5960 compatible, causing significant delays. This server problem
5961 has mostly been seen on redirects.
5963 By enabling this directive Squid attempts to detect such
5964 broken replies and automatically assume the reply is finished
5965 after 10 seconds timeout.
5969 CACHE DIGEST OPTIONS
5970 -----------------------------------------------------------------------------
5973 NAME: digest_generation
5974 IFDEF: USE_CACHE_DIGESTS
5976 LOC: Config.onoff.digest_generation
5979 This controls whether the server will generate a Cache Digest
5980 of its contents. By default, Cache Digest generation is
5981 enabled if Squid is compiled with --enable-cache-digests defined.
5984 NAME: digest_bits_per_entry
5985 IFDEF: USE_CACHE_DIGESTS
5987 LOC: Config.digest.bits_per_entry
5990 This is the number of bits of the server's Cache Digest which
5991 will be associated with the Digest entry for a given HTTP
5992 Method and URL (public key) combination. The default is 5.
5995 NAME: digest_rebuild_period
5996 IFDEF: USE_CACHE_DIGESTS
5999 LOC: Config.digest.rebuild_period
6002 This is the wait time between Cache Digest rebuilds.
6005 NAME: digest_rewrite_period
6007 IFDEF: USE_CACHE_DIGESTS
6009 LOC: Config.digest.rewrite_period
6012 This is the wait time between Cache Digest writes to
6016 NAME: digest_swapout_chunk_size
6019 IFDEF: USE_CACHE_DIGESTS
6020 LOC: Config.digest.swapout_chunk_size
6023 This is the number of bytes of the Cache Digest to write to
6024 disk at a time. It defaults to 4096 bytes (4KB), the Squid
6028 NAME: digest_rebuild_chunk_percentage
6029 COMMENT: (percent, 0-100)
6030 IFDEF: USE_CACHE_DIGESTS
6032 LOC: Config.digest.rebuild_chunk_percentage
6035 This is the percentage of the Cache Digest to be scanned at a
6036 time. By default it is set to 10% of the Cache Digest.
6041 -----------------------------------------------------------------------------
6046 LOC: Config.Port.snmp
6050 The port number where Squid listens for SNMP requests. To enable
6051 SNMP support set this to a suitable port number. Port number
6052 3401 is often used for the Squid SNMP agent. By default it's
6053 set to "0" (disabled)
6061 LOC: Config.accessList.snmp
6062 DEFAULT_IF_NONE: deny all
6065 Allowing or denying access to the SNMP port.
6067 All access to the agent is denied by default.
6070 snmp_access allow|deny [!]aclname ...
6072 This clause only supports fast acl types.
6073 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6075 snmp_access allow snmppublic localhost
6076 snmp_access deny all
6079 NAME: snmp_incoming_address
6081 LOC: Config.Addrs.snmp_incoming
6086 NAME: snmp_outgoing_address
6088 LOC: Config.Addrs.snmp_outgoing
6092 Just like 'udp_incoming_address', but for the SNMP port.
6094 snmp_incoming_address is used for the SNMP socket receiving
6095 messages from SNMP agents.
6096 snmp_outgoing_address is used for SNMP packets returned to SNMP
6099 The default snmp_incoming_address is to listen on all
6100 available network interfaces.
6102 If snmp_outgoing_address is not set it will use the same socket
6103 as snmp_incoming_address. Only change this if you want to have
6104 SNMP replies sent using another address than where this Squid
6105 listens for SNMP queries.
6107 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
6108 the same value since they both use port 3401.
6113 -----------------------------------------------------------------------------
6116 NAME: icp_port udp_port
6119 LOC: Config.Port.icp
6121 The port number where Squid sends and receives ICP queries to
6122 and from neighbor caches. The standard UDP port for ICP is 3130.
6123 Default is disabled (0).
6126 icp_port @DEFAULT_ICP_PORT@
6133 LOC: Config.Port.htcp
6135 The port number where Squid sends and receives HTCP queries to
6136 and from neighbor caches. To turn it on you want to set it to
6137 4827. By default it is set to "0" (disabled).
6143 NAME: log_icp_queries
6147 LOC: Config.onoff.log_udp
6149 If set, ICP queries are logged to access.log. You may wish
6150 do disable this if your ICP load is VERY high to speed things
6151 up or to simplify log analysis.
6154 NAME: udp_incoming_address
6156 LOC:Config.Addrs.udp_incoming
6159 udp_incoming_address is used for UDP packets received from other
6162 The default behavior is to not bind to any specific address.
6164 Only change this if you want to have all UDP queries received on
6165 a specific interface/address.
6167 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
6168 modules. Altering it will affect all of them in the same manner.
6170 see also; udp_outgoing_address
6172 NOTE, udp_incoming_address and udp_outgoing_address can not
6173 have the same value since they both use the same port.
6176 NAME: udp_outgoing_address
6178 LOC: Config.Addrs.udp_outgoing
6181 udp_outgoing_address is used for UDP packets sent out to other
6184 The default behavior is to not bind to any specific address.
6186 Instead it will use the same socket as udp_incoming_address.
6187 Only change this if you want to have UDP queries sent using another
6188 address than where this Squid listens for UDP queries from other
6191 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
6192 modules. Altering it will affect all of them in the same manner.
6194 see also; udp_incoming_address
6196 NOTE, udp_incoming_address and udp_outgoing_address can not
6197 have the same value since they both use the same port.
6204 LOC: Config.onoff.icp_hit_stale
6206 If you want to return ICP_HIT for stale cache objects, set this
6207 option to 'on'. If you have sibling relationships with caches
6208 in other administrative domains, this should be 'off'. If you only
6209 have sibling relationships with caches under your control,
6210 it is probably okay to set this to 'on'.
6211 If set to 'on', your siblings should use the option "allow-miss"
6212 on their cache_peer lines for connecting to you.
6215 NAME: minimum_direct_hops
6218 LOC: Config.minDirectHops
6220 If using the ICMP pinging stuff, do direct fetches for sites
6221 which are no more than this many hops away.
6224 NAME: minimum_direct_rtt
6227 LOC: Config.minDirectRtt
6229 If using the ICMP pinging stuff, do direct fetches for sites
6230 which are no more than this many rtt milliseconds away.
6236 LOC: Config.Netdb.low
6242 LOC: Config.Netdb.high
6244 The low and high water marks for the ICMP measurement
6245 database. These are counts, not percents. The defaults are
6246 900 and 1000. When the high water mark is reached, database
6247 entries will be deleted until the low mark is reached.
6250 NAME: netdb_ping_period
6252 LOC: Config.Netdb.period
6255 The minimum period for measuring a site. There will be at
6256 least this much delay between successive pings to the same
6257 network. The default is five minutes.
6264 LOC: Config.onoff.query_icmp
6266 If you want to ask your peers to include ICMP data in their ICP
6267 replies, enable this option.
6269 If your peer has configured Squid (during compilation) with
6270 '--enable-icmp' that peer will send ICMP pings to origin server
6271 sites of the URLs it receives. If you enable this option the
6272 ICP replies from that peer will include the ICMP data (if available).
6273 Then, when choosing a parent cache, Squid will choose the parent with
6274 the minimal RTT to the origin server. When this happens, the
6275 hierarchy field of the access.log will be
6276 "CLOSEST_PARENT_MISS". This option is off by default.
6279 NAME: test_reachability
6283 LOC: Config.onoff.test_reachability
6285 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
6286 instead of ICP_MISS if the target host is NOT in the ICMP
6287 database, or has a zero RTT.
6290 NAME: icp_query_timeout
6294 LOC: Config.Timeout.icp_query
6296 Normally Squid will automatically determine an optimal ICP
6297 query timeout value based on the round-trip-time of recent ICP
6298 queries. If you want to override the value determined by
6299 Squid, set this 'icp_query_timeout' to a non-zero value. This
6300 value is specified in MILLISECONDS, so, to use a 2-second
6301 timeout (the old default), you would write:
6303 icp_query_timeout 2000
6306 NAME: maximum_icp_query_timeout
6310 LOC: Config.Timeout.icp_query_max
6312 Normally the ICP query timeout is determined dynamically. But
6313 sometimes it can lead to very large values (say 5 seconds).
6314 Use this option to put an upper limit on the dynamic timeout
6315 value. Do NOT use this option to always use a fixed (instead
6316 of a dynamic) timeout value. To set a fixed timeout see the
6317 'icp_query_timeout' directive.
6320 NAME: minimum_icp_query_timeout
6324 LOC: Config.Timeout.icp_query_min
6326 Normally the ICP query timeout is determined dynamically. But
6327 sometimes it can lead to very small timeouts, even lower than
6328 the normal latency variance on your link due to traffic.
6329 Use this option to put an lower limit on the dynamic timeout
6330 value. Do NOT use this option to always use a fixed (instead
6331 of a dynamic) timeout value. To set a fixed timeout see the
6332 'icp_query_timeout' directive.
6335 NAME: background_ping_rate
6339 LOC: Config.backgroundPingRate
6341 Controls how often the ICP pings are sent to siblings that
6342 have background-ping set.
6346 MULTICAST ICP OPTIONS
6347 -----------------------------------------------------------------------------
6352 LOC: Config.mcast_group_list
6355 This tag specifies a list of multicast groups which your server
6356 should join to receive multicasted ICP queries.
6358 NOTE! Be very careful what you put here! Be sure you
6359 understand the difference between an ICP _query_ and an ICP
6360 _reply_. This option is to be set only if you want to RECEIVE
6361 multicast queries. Do NOT set this option to SEND multicast
6362 ICP (use cache_peer for that). ICP replies are always sent via
6363 unicast, so this option does not affect whether or not you will
6364 receive replies from multicast group members.
6366 You must be very careful to NOT use a multicast address which
6367 is already in use by another group of caches.
6369 If you are unsure about multicast, please read the Multicast
6370 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
6372 Usage: mcast_groups 239.128.16.128 224.0.1.20
6374 By default, Squid doesn't listen on any multicast groups.
6377 NAME: mcast_miss_addr
6378 IFDEF: MULTICAST_MISS_STREAM
6380 LOC: Config.mcast_miss.addr
6383 If you enable this option, every "cache miss" URL will
6384 be sent out on the specified multicast address.
6386 Do not enable this option unless you are are absolutely
6387 certain you understand what you are doing.
6390 NAME: mcast_miss_ttl
6391 IFDEF: MULTICAST_MISS_STREAM
6393 LOC: Config.mcast_miss.ttl
6396 This is the time-to-live value for packets multicasted
6397 when multicasting off cache miss URLs is enabled. By
6398 default this is set to 'site scope', i.e. 16.
6401 NAME: mcast_miss_port
6402 IFDEF: MULTICAST_MISS_STREAM
6404 LOC: Config.mcast_miss.port
6407 This is the port number to be used in conjunction with
6411 NAME: mcast_miss_encode_key
6412 IFDEF: MULTICAST_MISS_STREAM
6414 LOC: Config.mcast_miss.encode_key
6415 DEFAULT: XXXXXXXXXXXXXXXX
6417 The URLs that are sent in the multicast miss stream are
6418 encrypted. This is the encryption key.
6421 NAME: mcast_icp_query_timeout
6425 LOC: Config.Timeout.mcast_icp_query
6427 For multicast peers, Squid regularly sends out ICP "probes" to
6428 count how many other peers are listening on the given multicast
6429 address. This value specifies how long Squid should wait to
6430 count all the replies. The default is 2000 msec, or 2
6435 INTERNAL ICON OPTIONS
6436 -----------------------------------------------------------------------------
6439 NAME: icon_directory
6441 LOC: Config.icons.directory
6442 DEFAULT: @DEFAULT_ICON_DIR@
6444 Where the icons are stored. These are normally kept in
6448 NAME: global_internal_static
6450 LOC: Config.onoff.global_internal_static
6453 This directive controls is Squid should intercept all requests for
6454 /squid-internal-static/ no matter which host the URL is requesting
6455 (default on setting), or if nothing special should be done for
6456 such URLs (off setting). The purpose of this directive is to make
6457 icons etc work better in complex cache hierarchies where it may
6458 not always be possible for all corners in the cache mesh to reach
6459 the server generating a directory listing.
6462 NAME: short_icon_urls
6464 LOC: Config.icons.use_short_names
6467 If this is enabled Squid will use short URLs for icons.
6468 If disabled it will revert to the old behavior of including
6469 it's own name and port in the URL.
6471 If you run a complex cache hierarchy with a mix of Squid and
6472 other proxies you may need to disable this directive.
6477 -----------------------------------------------------------------------------
6480 NAME: error_directory
6482 LOC: Config.errorDirectory
6485 If you wish to create your own versions of the default
6486 error files to customize them to suit your company copy
6487 the error/template files to another directory and point
6490 WARNING: This option will disable multi-language support
6491 on error pages if used.
6493 The squid developers are interested in making squid available in
6494 a wide variety of languages. If you are making translations for a
6495 language that Squid does not currently provide please consider
6496 contributing your translation back to the project.
6497 http://wiki.squid-cache.org/Translations
6499 The squid developers working on translations are happy to supply drop-in
6500 translated error files in exchange for any new language contributions.
6503 NAME: error_default_language
6504 IFDEF: USE_ERR_LOCALES
6506 LOC: Config.errorDefaultLanguage
6509 Set the default language which squid will send error pages in
6510 if no existing translation matches the clients language
6513 If unset (default) generic English will be used.
6515 The squid developers are interested in making squid available in
6516 a wide variety of languages. If you are interested in making
6517 translations for any language see the squid wiki for details.
6518 http://wiki.squid-cache.org/Translations
6521 NAME: error_log_languages
6522 IFDEF: USE_ERR_LOCALES
6524 LOC: Config.errorLogMissingLanguages
6527 Log to cache.log what languages users are attempting to
6528 auto-negotiate for translations.
6530 Successful negotiations are not logged. Only failures
6531 have meaning to indicate that Squid may need an upgrade
6532 of its error page translations.
6535 NAME: err_page_stylesheet
6537 LOC: Config.errorStylesheet
6538 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
6540 CSS Stylesheet to pattern the display of Squid default error pages.
6542 For information on CSS see http://www.w3.org/Style/CSS/
6547 LOC: Config.errHtmlText
6550 HTML text to include in error messages. Make this a "mailto"
6551 URL to your admin address, or maybe just a link to your
6552 organizations Web page.
6554 To include this in your error messages, you must rewrite
6555 the error template files (found in the "errors" directory).
6556 Wherever you want the 'err_html_text' line to appear,
6557 insert a %L tag in the error template file.
6560 NAME: email_err_data
6563 LOC: Config.onoff.emailErrData
6566 If enabled, information about the occurred error will be
6567 included in the mailto links of the ERR pages (if %W is set)
6568 so that the email body contains the data.
6569 Syntax is <A HREF="mailto:%w%W">%w</A>
6574 LOC: Config.denyInfoList
6577 Usage: deny_info err_page_name acl
6578 or deny_info http://... acl
6579 or deny_info TCP_RESET acl
6581 This can be used to return a ERR_ page for requests which
6582 do not pass the 'http_access' rules. Squid remembers the last
6583 acl it evaluated in http_access, and if a 'deny_info' line exists
6584 for that ACL Squid returns a corresponding error page.
6586 The acl is typically the last acl on the http_access deny line which
6587 denied access. The exceptions to this rule are:
6588 - When Squid needs to request authentication credentials. It's then
6589 the first authentication related acl encountered
6590 - When none of the http_access lines matches. It's then the last
6591 acl processed on the last http_access line.
6592 - When the decision to deny access was made by an adaptation service,
6593 the acl name is the corresponding eCAP or ICAP service_name.
6595 NP: If providing your own custom error pages with error_directory
6596 you may also specify them by your custom file name:
6597 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
6599 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
6600 may be specified by prefixing the file name with the code and a colon.
6601 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
6603 Alternatively you can tell Squid to reset the TCP connection
6604 by specifying TCP_RESET.
6606 Or you can specify an error URL or URL pattern. The browsers will
6607 get redirected to the specified URL after formatting tags have
6608 been replaced. Redirect will be done with 302 or 307 according to
6609 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
6610 the URL. e.g. 303:http://example.com/
6613 %a - username (if available. Password NOT included)
6616 %E - Error description
6618 %H - Request domain name
6619 %i - Client IP Address
6621 %o - Message result from external ACL helper
6622 %p - Request Port number
6623 %P - Request Protocol name
6624 %R - Request URL path
6625 %T - Timestamp in RFC 1123 format
6626 %U - Full canonical URL from client
6627 (HTTPS URLs terminate with *)
6628 %u - Full canonical URL from client
6629 %w - Admin email from squid.conf
6631 %% - Literal percent (%) code
6636 OPTIONS INFLUENCING REQUEST FORWARDING
6637 -----------------------------------------------------------------------------
6640 NAME: nonhierarchical_direct
6642 LOC: Config.onoff.nonhierarchical_direct
6645 By default, Squid will send any non-hierarchical requests
6646 (matching hierarchy_stoplist or not cacheable request type) direct
6649 If you set this to off, Squid will prefer to send these
6650 requests to parents.
6652 Note that in most configurations, by turning this off you will only
6653 add latency to these request without any improvement in global hit
6656 If you are inside an firewall see never_direct instead of
6662 LOC: Config.onoff.prefer_direct
6665 Normally Squid tries to use parents for most requests. If you for some
6666 reason like it to first try going direct and only use a parent if
6667 going direct fails set this to on.
6669 By combining nonhierarchical_direct off and prefer_direct on you
6670 can set up Squid to use a parent as a backup path if going direct
6673 Note: If you want Squid to use parents for all requests see
6674 the never_direct directive. prefer_direct only modifies how Squid
6675 acts on cacheable requests.
6680 LOC: Config.accessList.AlwaysDirect
6683 Usage: always_direct allow|deny [!]aclname ...
6685 Here you can use ACL elements to specify requests which should
6686 ALWAYS be forwarded by Squid to the origin servers without using
6687 any peers. For example, to always directly forward requests for
6688 local servers ignoring any parents or siblings you may have use
6691 acl local-servers dstdomain my.domain.net
6692 always_direct allow local-servers
6694 To always forward FTP requests directly, use
6697 always_direct allow FTP
6699 NOTE: There is a similar, but opposite option named
6700 'never_direct'. You need to be aware that "always_direct deny
6701 foo" is NOT the same thing as "never_direct allow foo". You
6702 may need to use a deny rule to exclude a more-specific case of
6703 some other rule. Example:
6705 acl local-external dstdomain external.foo.net
6706 acl local-servers dstdomain .foo.net
6707 always_direct deny local-external
6708 always_direct allow local-servers
6710 NOTE: If your goal is to make the client forward the request
6711 directly to the origin server bypassing Squid then this needs
6712 to be done in the client configuration. Squid configuration
6713 can only tell Squid how Squid should fetch the object.
6715 NOTE: This directive is not related to caching. The replies
6716 is cached as usual even if you use always_direct. To not cache
6717 the replies see the 'cache' directive.
6719 This clause supports both fast and slow acl types.
6720 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6725 LOC: Config.accessList.NeverDirect
6728 Usage: never_direct allow|deny [!]aclname ...
6730 never_direct is the opposite of always_direct. Please read
6731 the description for always_direct if you have not already.
6733 With 'never_direct' you can use ACL elements to specify
6734 requests which should NEVER be forwarded directly to origin
6735 servers. For example, to force the use of a proxy for all
6736 requests, except those in your local domain use something like:
6738 acl local-servers dstdomain .foo.net
6739 never_direct deny local-servers
6740 never_direct allow all
6742 or if Squid is inside a firewall and there are local intranet
6743 servers inside the firewall use something like:
6745 acl local-intranet dstdomain .foo.net
6746 acl local-external dstdomain external.foo.net
6747 always_direct deny local-external
6748 always_direct allow local-intranet
6749 never_direct allow all
6751 This clause supports both fast and slow acl types.
6752 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6756 ADVANCED NETWORKING OPTIONS
6757 -----------------------------------------------------------------------------
6760 NAME: incoming_udp_average incoming_icp_average
6763 LOC: Config.comm_incoming.udp.average
6765 Heavy voodoo here. I can't even believe you are reading this.
6766 Are you crazy? Don't even think about adjusting these unless
6767 you understand the algorithms in comm_select.c first!
6770 NAME: incoming_tcp_average incoming_http_average
6773 LOC: Config.comm_incoming.tcp.average
6775 Heavy voodoo here. I can't even believe you are reading this.
6776 Are you crazy? Don't even think about adjusting these unless
6777 you understand the algorithms in comm_select.c first!
6780 NAME: incoming_dns_average
6783 LOC: Config.comm_incoming.dns.average
6785 Heavy voodoo here. I can't even believe you are reading this.
6786 Are you crazy? Don't even think about adjusting these unless
6787 you understand the algorithms in comm_select.c first!
6790 NAME: min_udp_poll_cnt min_icp_poll_cnt
6793 LOC: Config.comm_incoming.udp.min_poll
6795 Heavy voodoo here. I can't even believe you are reading this.
6796 Are you crazy? Don't even think about adjusting these unless
6797 you understand the algorithms in comm_select.c first!
6800 NAME: min_dns_poll_cnt
6803 LOC: Config.comm_incoming.dns.min_poll
6805 Heavy voodoo here. I can't even believe you are reading this.
6806 Are you crazy? Don't even think about adjusting these unless
6807 you understand the algorithms in comm_select.c first!
6810 NAME: min_tcp_poll_cnt min_http_poll_cnt
6813 LOC: Config.comm_incoming.tcp.min_poll
6815 Heavy voodoo here. I can't even believe you are reading this.
6816 Are you crazy? Don't even think about adjusting these unless
6817 you understand the algorithms in comm_select.c first!
6823 LOC: Config.accept_filter
6827 The name of an accept(2) filter to install on Squid's
6828 listen socket(s). This feature is perhaps specific to
6829 FreeBSD and requires support in the kernel.
6831 The 'httpready' filter delays delivering new connections
6832 to Squid until a full HTTP request has been received.
6833 See the accf_http(9) man page for details.
6835 The 'dataready' filter delays delivering new connections
6836 to Squid until there is some data to process.
6837 See the accf_dataready(9) man page for details.
6841 The 'data' filter delays delivering of new connections
6842 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
6843 You may optionally specify a number of seconds to wait by
6844 'data=N' where N is the number of seconds. Defaults to 30
6845 if not specified. See the tcp(7) man page for details.
6848 accept_filter httpready
6853 NAME: client_ip_max_connections
6855 LOC: Config.client_ip_max_connections
6858 Set an absolute limit on the number of connections a single
6859 client IP can use. Any more than this and Squid will begin to drop
6860 new connections from the client until it closes some links.
6862 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
6863 connections from the client. For finer control use the ACL access controls.
6865 Requires client_db to be enabled (the default).
6867 WARNING: This may noticably slow down traffic received via external proxies
6868 or NAT devices and cause them to rebound error messages back to their clients.
6871 NAME: tcp_recv_bufsize
6875 LOC: Config.tcpRcvBufsz
6877 Size of receive buffer to set for TCP sockets. Probably just
6878 as easy to change your kernel's default. Set to zero to use
6879 the default buffer size.
6884 -----------------------------------------------------------------------------
6891 LOC: Adaptation::Icap::TheConfig.onoff
6894 If you want to enable the ICAP module support, set this to on.
6897 NAME: icap_connect_timeout
6900 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
6903 This parameter specifies how long to wait for the TCP connect to
6904 the requested ICAP server to complete before giving up and either
6905 terminating the HTTP transaction or bypassing the failure.
6907 The default for optional services is peer_connect_timeout.
6908 The default for essential services is connect_timeout.
6909 If this option is explicitly set, its value applies to all services.
6912 NAME: icap_io_timeout
6916 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
6919 This parameter specifies how long to wait for an I/O activity on
6920 an established, active ICAP connection before giving up and
6921 either terminating the HTTP transaction or bypassing the
6924 The default is read_timeout.
6927 NAME: icap_service_failure_limit
6928 COMMENT: limit [in memory-depth time-units]
6929 TYPE: icap_service_failure_limit
6931 LOC: Adaptation::Icap::TheConfig
6934 The limit specifies the number of failures that Squid tolerates
6935 when establishing a new TCP connection with an ICAP service. If
6936 the number of failures exceeds the limit, the ICAP service is
6937 not used for new ICAP requests until it is time to refresh its
6940 A negative value disables the limit. Without the limit, an ICAP
6941 service will not be considered down due to connectivity failures
6942 between ICAP OPTIONS requests.
6944 Squid forgets ICAP service failures older than the specified
6945 value of memory-depth. The memory fading algorithm
6946 is approximate because Squid does not remember individual
6947 errors but groups them instead, splitting the option
6948 value into ten time slots of equal length.
6950 When memory-depth is 0 and by default this option has no
6951 effect on service failure expiration.
6953 Squid always forgets failures when updating service settings
6954 using an ICAP OPTIONS transaction, regardless of this option
6958 # suspend service usage after 10 failures in 5 seconds:
6959 icap_service_failure_limit 10 in 5 seconds
6962 NAME: icap_service_revival_delay
6965 LOC: Adaptation::Icap::TheConfig.service_revival_delay
6968 The delay specifies the number of seconds to wait after an ICAP
6969 OPTIONS request failure before requesting the options again. The
6970 failed ICAP service is considered "down" until fresh OPTIONS are
6973 The actual delay cannot be smaller than the hardcoded minimum
6974 delay of 30 seconds.
6977 NAME: icap_preview_enable
6981 LOC: Adaptation::Icap::TheConfig.preview_enable
6984 The ICAP Preview feature allows the ICAP server to handle the
6985 HTTP message by looking only at the beginning of the message body
6986 or even without receiving the body at all. In some environments,
6987 previews greatly speedup ICAP processing.
6989 During an ICAP OPTIONS transaction, the server may tell Squid what
6990 HTTP messages should be previewed and how big the preview should be.
6991 Squid will not use Preview if the server did not request one.
6993 To disable ICAP Preview for all ICAP services, regardless of
6994 individual ICAP server OPTIONS responses, set this option to "off".
6996 icap_preview_enable off
6999 NAME: icap_preview_size
7002 LOC: Adaptation::Icap::TheConfig.preview_size
7005 The default size of preview data to be sent to the ICAP server.
7006 -1 means no preview. This value might be overwritten on a per server
7007 basis by OPTIONS requests.
7010 NAME: icap_206_enable
7014 LOC: Adaptation::Icap::TheConfig.allow206_enable
7017 206 (Partial Content) responses is an ICAP extension that allows the
7018 ICAP agents to optionally combine adapted and original HTTP message
7019 content. The decision to combine is postponed until the end of the
7020 ICAP response. Squid supports Partial Content extension by default.
7022 Activation of the Partial Content extension is negotiated with each
7023 ICAP service during OPTIONS exchange. Most ICAP servers should handle
7024 negotation correctly even if they do not support the extension, but
7025 some might fail. To disable Partial Content support for all ICAP
7026 services and to avoid any negotiation, set this option to "off".
7032 NAME: icap_default_options_ttl
7035 LOC: Adaptation::Icap::TheConfig.default_options_ttl
7038 The default TTL value for ICAP OPTIONS responses that don't have
7039 an Options-TTL header.
7042 NAME: icap_persistent_connections
7046 LOC: Adaptation::Icap::TheConfig.reuse_connections
7049 Whether or not Squid should use persistent connections to
7053 NAME: adaptation_send_client_ip icap_send_client_ip
7055 IFDEF: USE_ADAPTATION
7057 LOC: Adaptation::Config::send_client_ip
7060 If enabled, Squid shares HTTP client IP information with adaptation
7061 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
7062 For eCAP, Squid sets the libecap::metaClientIp transaction option.
7064 See also: adaptation_uses_indirect_client
7067 NAME: adaptation_send_username icap_send_client_username
7069 IFDEF: USE_ADAPTATION
7071 LOC: Adaptation::Config::send_username
7074 This sends authenticated HTTP client username (if available) to
7075 the adaptation service.
7077 For ICAP, the username value is encoded based on the
7078 icap_client_username_encode option and is sent using the header
7079 specified by the icap_client_username_header option.
7082 NAME: icap_client_username_header
7085 LOC: Adaptation::Icap::TheConfig.client_username_header
7086 DEFAULT: X-Client-Username
7088 ICAP request header name to use for adaptation_send_username.
7091 NAME: icap_client_username_encode
7095 LOC: Adaptation::Icap::TheConfig.client_username_encode
7098 Whether to base64 encode the authenticated client username.
7102 TYPE: icap_service_type
7104 LOC: Adaptation::Icap::TheConfig
7107 Defines a single ICAP service using the following format:
7109 icap_service id vectoring_point uri [option ...]
7112 an opaque identifier or name which is used to direct traffic to
7113 this specific service. Must be unique among all adaptation
7114 services in squid.conf.
7116 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7117 This specifies at which point of transaction processing the
7118 ICAP service should be activated. *_postcache vectoring points
7119 are not yet supported.
7121 uri: icap://servername:port/servicepath
7122 ICAP server and service location.
7124 ICAP does not allow a single service to handle both REQMOD and RESPMOD
7125 transactions. Squid does not enforce that requirement. You can specify
7126 services with the same service_url and different vectoring_points. You
7127 can even specify multiple identical services as long as their
7128 service_names differ.
7131 Service options are separated by white space. ICAP services support
7132 the following name=value options:
7135 If set to 'on' or '1', the ICAP service is treated as
7136 optional. If the service cannot be reached or malfunctions,
7137 Squid will try to ignore any errors and process the message as
7138 if the service was not enabled. No all ICAP errors can be
7139 bypassed. If set to 0, the ICAP service is treated as
7140 essential and all ICAP errors will result in an error page
7141 returned to the HTTP client.
7143 Bypass is off by default: services are treated as essential.
7146 If set to 'on' or '1', the ICAP service is allowed to
7147 dynamically change the current message adaptation plan by
7148 returning a chain of services to be used next. The services
7149 are specified using the X-Next-Services ICAP response header
7150 value, formatted as a comma-separated list of service names.
7151 Each named service should be configured in squid.conf. Other
7152 services are ignored. An empty X-Next-Services value results
7153 in an empty plan which ends the current adaptation.
7155 Dynamic adaptation plan may cross or cover multiple supported
7156 vectoring points in their natural processing order.
7158 Routing is not allowed by default: the ICAP X-Next-Services
7159 response header is ignored.
7162 Only has effect on split-stack systems. The default on those systems
7163 is to use IPv4-only connections. When set to 'on' this option will
7164 make Squid use IPv6-only connections to contact this ICAP service.
7166 on-overload=block|bypass|wait|force
7167 If the service Max-Connections limit has been reached, do
7168 one of the following for each new ICAP transaction:
7169 * block: send an HTTP error response to the client
7170 * bypass: ignore the "over-connected" ICAP service
7171 * wait: wait (in a FIFO queue) for an ICAP connection slot
7172 * force: proceed, ignoring the Max-Connections limit
7174 In SMP mode with N workers, each worker assumes the service
7175 connection limit is Max-Connections/N, even though not all
7176 workers may use a given service.
7178 The default value is "bypass" if service is bypassable,
7179 otherwise it is set to "wait".
7183 Use the given number as the Max-Connections limit, regardless
7184 of the Max-Connections value given by the service, if any.
7186 Older icap_service format without optional named parameters is
7187 deprecated but supported for backward compatibility.
7190 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
7191 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
7195 TYPE: icap_class_type
7200 This deprecated option was documented to define an ICAP service
7201 chain, even though it actually defined a set of similar, redundant
7202 services, and the chains were not supported.
7204 To define a set of redundant services, please use the
7205 adaptation_service_set directive. For service chains, use
7206 adaptation_service_chain.
7210 TYPE: icap_access_type
7215 This option is deprecated. Please use adaptation_access, which
7216 has the same ICAP functionality, but comes with better
7217 documentation, and eCAP support.
7222 -----------------------------------------------------------------------------
7229 LOC: Adaptation::Ecap::TheConfig.onoff
7232 Controls whether eCAP support is enabled.
7236 TYPE: ecap_service_type
7238 LOC: Adaptation::Ecap::TheConfig
7241 Defines a single eCAP service
7243 ecap_service id vectoring_point uri [option ...]
7246 an opaque identifier or name which is used to direct traffic to
7247 this specific service. Must be unique among all adaptation
7248 services in squid.conf.
7250 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7251 This specifies at which point of transaction processing the
7252 eCAP service should be activated. *_postcache vectoring points
7253 are not yet supported.
7255 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
7256 Squid uses the eCAP service URI to match this configuration
7257 line with one of the dynamically loaded services. Each loaded
7258 eCAP service must have a unique URI. Obtain the right URI from
7259 the service provider.
7262 Service options are separated by white space. eCAP services support
7263 the following name=value options:
7266 If set to 'on' or '1', the eCAP service is treated as optional.
7267 If the service cannot be reached or malfunctions, Squid will try
7268 to ignore any errors and process the message as if the service
7269 was not enabled. No all eCAP errors can be bypassed.
7270 If set to 'off' or '0', the eCAP service is treated as essential
7271 and all eCAP errors will result in an error page returned to the
7274 Bypass is off by default: services are treated as essential.
7277 If set to 'on' or '1', the eCAP service is allowed to
7278 dynamically change the current message adaptation plan by
7279 returning a chain of services to be used next.
7281 Dynamic adaptation plan may cross or cover multiple supported
7282 vectoring points in their natural processing order.
7284 Routing is not allowed by default.
7286 Older ecap_service format without optional named parameters is
7287 deprecated but supported for backward compatibility.
7291 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
7292 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
7295 NAME: loadable_modules
7297 IFDEF: USE_LOADABLE_MODULES
7298 LOC: Config.loadable_module_names
7301 Instructs Squid to load the specified dynamic module(s) or activate
7302 preloaded module(s).
7304 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
7308 MESSAGE ADAPTATION OPTIONS
7309 -----------------------------------------------------------------------------
7312 NAME: adaptation_service_set
7313 TYPE: adaptation_service_set_type
7314 IFDEF: USE_ADAPTATION
7319 Configures an ordered set of similar, redundant services. This is
7320 useful when hot standby or backup adaptation servers are available.
7322 adaptation_service_set set_name service_name1 service_name2 ...
7324 The named services are used in the set declaration order. The first
7325 applicable adaptation service from the set is used first. The next
7326 applicable service is tried if and only if the transaction with the
7327 previous service fails and the message waiting to be adapted is still
7330 When adaptation starts, broken services are ignored as if they were
7331 not a part of the set. A broken service is a down optional service.
7333 The services in a set must be attached to the same vectoring point
7334 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7336 If all services in a set are optional then adaptation failures are
7337 bypassable. If all services in the set are essential, then a
7338 transaction failure with one service may still be retried using
7339 another service from the set, but when all services fail, the master
7340 transaction fails as well.
7342 A set may contain a mix of optional and essential services, but that
7343 is likely to lead to surprising results because broken services become
7344 ignored (see above), making previously bypassable failures fatal.
7345 Technically, it is the bypassability of the last failed service that
7348 See also: adaptation_access adaptation_service_chain
7351 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
7352 adaptation service_set svcLogger loggerLocal loggerRemote
7355 NAME: adaptation_service_chain
7356 TYPE: adaptation_service_chain_type
7357 IFDEF: USE_ADAPTATION
7362 Configures a list of complementary services that will be applied
7363 one-by-one, forming an adaptation chain or pipeline. This is useful
7364 when Squid must perform different adaptations on the same message.
7366 adaptation_service_chain chain_name service_name1 svc_name2 ...
7368 The named services are used in the chain declaration order. The first
7369 applicable adaptation service from the chain is used first. The next
7370 applicable service is applied to the successful adaptation results of
7371 the previous service in the chain.
7373 When adaptation starts, broken services are ignored as if they were
7374 not a part of the chain. A broken service is a down optional service.
7376 Request satisfaction terminates the adaptation chain because Squid
7377 does not currently allow declaration of RESPMOD services at the
7378 "reqmod_precache" vectoring point (see icap_service or ecap_service).
7380 The services in a chain must be attached to the same vectoring point
7381 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7383 A chain may contain a mix of optional and essential services. If an
7384 essential adaptation fails (or the failure cannot be bypassed for
7385 other reasons), the master transaction fails. Otherwise, the failure
7386 is bypassed as if the failed adaptation service was not in the chain.
7388 See also: adaptation_access adaptation_service_set
7391 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
7394 NAME: adaptation_access
7395 TYPE: adaptation_access_type
7396 IFDEF: USE_ADAPTATION
7400 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
7402 adaptation_access service_name allow|deny [!]aclname...
7403 adaptation_access set_name allow|deny [!]aclname...
7405 At each supported vectoring point, the adaptation_access
7406 statements are processed in the order they appear in this
7407 configuration file. Statements pointing to the following services
7408 are ignored (i.e., skipped without checking their ACL):
7410 - services serving different vectoring points
7411 - "broken-but-bypassable" services
7412 - "up" services configured to ignore such transactions
7413 (e.g., based on the ICAP Transfer-Ignore header).
7415 When a set_name is used, all services in the set are checked
7416 using the same rules, to find the first applicable one. See
7417 adaptation_service_set for details.
7419 If an access list is checked and there is a match, the
7420 processing stops: For an "allow" rule, the corresponding
7421 adaptation service is used for the transaction. For a "deny"
7422 rule, no adaptation service is activated.
7424 It is currently not possible to apply more than one adaptation
7425 service at the same vectoring point to the same HTTP transaction.
7427 See also: icap_service and ecap_service
7430 adaptation_access service_1 allow all
7433 NAME: adaptation_service_iteration_limit
7435 IFDEF: USE_ADAPTATION
7436 LOC: Adaptation::Config::service_iteration_limit
7439 Limits the number of iterations allowed when applying adaptation
7440 services to a message. If your longest adaptation set or chain
7441 may have more than 16 services, increase the limit beyond its
7442 default value of 16. If detecting infinite iteration loops sooner
7443 is critical, make the iteration limit match the actual number
7444 of services in your longest adaptation set or chain.
7446 Infinite adaptation loops are most likely with routing services.
7448 See also: icap_service routing=1
7451 NAME: adaptation_masterx_shared_names
7453 IFDEF: USE_ADAPTATION
7454 LOC: Adaptation::Config::masterx_shared_name
7457 For each master transaction (i.e., the HTTP request and response
7458 sequence, including all related ICAP and eCAP exchanges), Squid
7459 maintains a table of metadata. The table entries are (name, value)
7460 pairs shared among eCAP and ICAP exchanges. The table is destroyed
7461 with the master transaction.
7463 This option specifies the table entry names that Squid must accept
7464 from and forward to the adaptation transactions.
7466 An ICAP REQMOD or RESPMOD transaction may set an entry in the
7467 shared table by returning an ICAP header field with a name
7468 specified in adaptation_masterx_shared_names.
7470 An eCAP REQMOD or RESPMOD transaction may set an entry in the
7471 shared table by implementing the libecap::visitEachOption() API
7472 to provide an option with a name specified in
7473 adaptation_masterx_shared_names.
7475 Squid will store and forward the set entry to subsequent adaptation
7476 transactions within the same master transaction scope.
7478 Only one shared entry name is supported at this time.
7481 # share authentication information among ICAP services
7482 adaptation_masterx_shared_names X-Subscriber-ID
7485 NAME: adaptation_meta
7487 IFDEF: USE_ADAPTATION
7488 LOC: Adaptation::Config::metaHeaders
7491 This option allows Squid administrator to add custom ICAP request
7492 headers or eCAP options to Squid ICAP requests or eCAP transactions.
7493 Use it to pass custom authentication tokens and other
7494 transaction-state related meta information to an ICAP/eCAP service.
7496 The addition of a meta header is ACL-driven:
7497 adaptation_meta name value [!]aclname ...
7499 Processing for a given header name stops after the first ACL list match.
7500 Thus, it is impossible to add two headers with the same name. If no ACL
7501 lists match for a given header name, no such header is added. For
7504 # do not debug transactions except for those that need debugging
7505 adaptation_meta X-Debug 1 needs_debugging
7507 # log all transactions except for those that must remain secret
7508 adaptation_meta X-Log 1 !keep_secret
7510 # mark transactions from users in the "G 1" group
7511 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
7513 The "value" parameter may be a regular squid.conf token or a "double
7514 quoted string". Within the quoted string, use backslash (\) to escape
7515 any character, which is currently only useful for escaping backslashes
7516 and double quotes. For example,
7517 "this string has one backslash (\\) and two \"quotes\""
7519 Used adaptation_meta header values may be logged via %note
7520 logformat code. If multiple adaptation_meta headers with the same name
7521 are used during master transaction lifetime, the header values are
7522 logged in the order they were used and duplicate values are ignored
7523 (only the first repeated value will be logged).
7529 LOC: Adaptation::Icap::TheConfig.repeat
7530 DEFAULT_IF_NONE: deny all
7532 This ACL determines which retriable ICAP transactions are
7533 retried. Transactions that received a complete ICAP response
7534 and did not have to consume or produce HTTP bodies to receive
7535 that response are usually retriable.
7537 icap_retry allow|deny [!]aclname ...
7539 Squid automatically retries some ICAP I/O timeouts and errors
7540 due to persistent connection race conditions.
7542 See also: icap_retry_limit
7545 NAME: icap_retry_limit
7548 LOC: Adaptation::Icap::TheConfig.repeat_limit
7551 Limits the number of retries allowed. When set to zero (default),
7552 no retries are allowed.
7554 Communication errors due to persistent connection race
7555 conditions are unavoidable, automatically retried, and do not
7556 count against this limit.
7558 See also: icap_retry
7564 -----------------------------------------------------------------------------
7567 NAME: check_hostnames
7570 LOC: Config.onoff.check_hostnames
7572 For security and stability reasons Squid can check
7573 hostnames for Internet standard RFC compliance. If you want
7574 Squid to perform these checks turn this directive on.
7577 NAME: allow_underscore
7580 LOC: Config.onoff.allow_underscore
7582 Underscore characters is not strictly allowed in Internet hostnames
7583 but nevertheless used by many sites. Set this to off if you want
7584 Squid to be strict about the standard.
7585 This check is performed only when check_hostnames is set to on.
7588 NAME: cache_dns_program
7590 IFDEF: USE_DNSHELPER
7591 DEFAULT: @DEFAULT_DNSSERVER@
7592 LOC: Config.Program.dnsserver
7594 Specify the location of the executable for dnslookup process.
7598 TYPE: HelperChildConfig
7599 IFDEF: USE_DNSHELPER
7600 DEFAULT: 32 startup=1 idle=1
7601 LOC: Config.dnsChildren
7603 The maximum number of processes spawn to service DNS name lookups.
7604 If you limit it too few Squid will have to wait for them to process
7605 a backlog of requests, slowing it down. If you allow too many they
7606 will use RAM and other system resources noticably.
7607 The maximum this may be safely set to is 32.
7609 The startup= and idle= options allow some measure of skew in your
7614 Sets a minimum of how many processes are to be spawned when Squid
7615 starts or reconfigures. When set to zero the first request will
7616 cause spawning of the first child process to handle it.
7618 Starting too few will cause an initial slowdown in traffic as Squid
7619 attempts to simultaneously spawn enough processes to cope.
7623 Sets a minimum of how many processes Squid is to try and keep available
7624 at all times. When traffic begins to rise above what the existing
7625 processes can handle this many more will be spawned up to the maximum
7626 configured. A minimum setting of 1 is required.
7629 NAME: dns_retransmit_interval
7632 LOC: Config.Timeout.idns_retransmit
7633 IFDEF: !USE_DNSHELPER
7635 Initial retransmit interval for DNS queries. The interval is
7636 doubled each time all configured DNS servers have been tried.
7642 LOC: Config.Timeout.idns_query
7643 IFDEF: !USE_DNSHELPER
7645 DNS Query timeout. If no response is received to a DNS query
7646 within this time all DNS servers for the queried domain
7647 are assumed to be unavailable.
7650 NAME: dns_packet_max
7653 LOC: Config.dns.packet_max
7654 IFDEF: !USE_DNSHELPER
7656 Maximum number of bytes packet size to advertise via EDNS.
7657 Set to "none" to disable EDNS large packet support.
7659 For legacy reasons DNS UDP replies will default to 512 bytes which
7660 is too small for many responses. EDNS provides a means for Squid to
7661 negotiate receiving larger responses back immediately without having
7662 to failover with repeat requests. Responses larger than this limit
7663 will retain the old behaviour of failover to TCP DNS.
7665 Squid has no real fixed limit internally, but allowing packet sizes
7666 over 1500 bytes requires network jumbogram support and is usually not
7669 WARNING: The RFC also indicates that some older resolvers will reply
7670 with failure of the whole request if the extension is added. Some
7671 resolvers have already been identified which will reply with mangled
7672 EDNS response on occasion. Usually in response to many-KB jumbogram
7673 sizes being advertised by Squid.
7674 Squid will currently treat these both as an unable-to-resolve domain
7675 even if it would be resolvable without EDNS.
7682 LOC: Config.onoff.res_defnames
7684 Normally the RES_DEFNAMES resolver option is disabled
7685 (see res_init(3)). This prevents caches in a hierarchy
7686 from interpreting single-component hostnames locally. To allow
7687 Squid to handle single-component names, enable this option.
7690 NAME: dns_nameservers
7693 LOC: Config.dns_nameservers
7695 Use this if you want to specify a list of DNS name servers
7696 (IP addresses) to use instead of those given in your
7697 /etc/resolv.conf file.
7698 On Windows platforms, if no value is specified here or in
7699 the /etc/resolv.conf file, the list of DNS name servers are
7700 taken from the Windows registry, both static and dynamic DHCP
7701 configurations are supported.
7703 Example: dns_nameservers 10.0.0.1 192.172.0.4
7708 DEFAULT: @DEFAULT_HOSTS@
7709 LOC: Config.etcHostsPath
7711 Location of the host-local IP name-address associations
7712 database. Most Operating Systems have such a file on different
7714 - Un*X & Linux: /etc/hosts
7715 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
7716 (%SystemRoot% value install default is c:\winnt)
7717 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
7718 (%SystemRoot% value install default is c:\windows)
7719 - Windows 9x/Me: %windir%\hosts
7720 (%windir% value is usually c:\windows)
7721 - Cygwin: /etc/hosts
7723 The file contains newline-separated definitions, in the
7724 form ip_address_in_dotted_form name [name ...] names are
7725 whitespace-separated. Lines beginning with an hash (#)
7726 character are comments.
7728 The file is checked at startup and upon configuration.
7729 If set to 'none', it won't be checked.
7730 If append_domain is used, that domain will be added to
7731 domain-local (i.e. not containing any dot character) host
7737 LOC: Config.appendDomain
7740 Appends local domain name to hostnames without any dots in
7741 them. append_domain must begin with a period.
7743 Be warned there are now Internet names with no dots in
7744 them using only top-domain names, so setting this may
7745 cause some Internet sites to become unavailable.
7748 append_domain .yourdomain.com
7751 NAME: ignore_unknown_nameservers
7753 LOC: Config.onoff.ignore_unknown_nameservers
7755 IFDEF: !USE_DNSHELPER
7757 By default Squid checks that DNS responses are received
7758 from the same IP addresses they are sent to. If they
7759 don't match, Squid ignores the response and writes a warning
7760 message to cache.log. You can allow responses from unknown
7761 nameservers by setting this option to 'off'.
7767 LOC: Config.dns.v4_first
7768 IFDEF: !USE_DNSHELPER
7770 With the IPv6 Internet being as fast or faster than IPv4 Internet
7771 for most networks Squid prefers to contact websites over IPv6.
7773 This option reverses the order of preference to make Squid contact
7774 dual-stack websites over IPv4 first. Squid will still perform both
7775 IPv6 and IPv4 DNS lookups before connecting.
7778 This option will restrict the situations under which IPv6
7779 connectivity is used (and tested). Hiding network problems
7780 which would otherwise be detected and warned about.
7784 COMMENT: (number of entries)
7787 LOC: Config.ipcache.size
7794 LOC: Config.ipcache.low
7801 LOC: Config.ipcache.high
7803 The size, low-, and high-water marks for the IP cache.
7806 NAME: fqdncache_size
7807 COMMENT: (number of entries)
7810 LOC: Config.fqdncache.size
7812 Maximum number of FQDN cache entries.
7817 -----------------------------------------------------------------------------
7824 LOC: Config.onoff.mem_pools
7826 If set, Squid will keep pools of allocated (but unused) memory
7827 available for future use. If memory is a premium on your
7828 system and you believe your malloc library outperforms Squid
7829 routines, disable this.
7832 NAME: memory_pools_limit
7836 LOC: Config.MemPools.limit
7838 Used only with memory_pools on:
7839 memory_pools_limit 50 MB
7841 If set to a non-zero value, Squid will keep at most the specified
7842 limit of allocated (but unused) memory in memory pools. All free()
7843 requests that exceed this limit will be handled by your malloc
7844 library. Squid does not pre-allocate any memory, just safe-keeps
7845 objects that otherwise would be free()d. Thus, it is safe to set
7846 memory_pools_limit to a reasonably high value even if your
7847 configuration will use less memory.
7849 If set to none, Squid will keep all memory it can. That is, there
7850 will be no limit on the total amount of memory used for safe-keeping.
7852 To disable memory allocation optimization, do not set
7853 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
7855 An overhead for maintaining memory pools is not taken into account
7856 when the limit is checked. This overhead is close to four bytes per
7857 object kept. However, pools may actually _save_ memory because of
7858 reduced memory thrashing in your malloc library.
7862 COMMENT: on|off|transparent|truncate|delete
7865 LOC: opt_forwarded_for
7867 If set to "on", Squid will append your client's IP address
7868 in the HTTP requests it forwards. By default it looks like:
7870 X-Forwarded-For: 192.1.2.3
7872 If set to "off", it will appear as
7874 X-Forwarded-For: unknown
7876 If set to "transparent", Squid will not alter the
7877 X-Forwarded-For header in any way.
7879 If set to "delete", Squid will delete the entire
7880 X-Forwarded-For header.
7882 If set to "truncate", Squid will remove all existing
7883 X-Forwarded-For entries, and place the client IP as the sole entry.
7886 NAME: cachemgr_passwd
7887 TYPE: cachemgrpasswd
7889 LOC: Config.passwd_list
7891 Specify passwords for cachemgr operations.
7893 Usage: cachemgr_passwd password action action ...
7895 Some valid actions are (see cache manager menu for a full list):
7935 * Indicates actions which will not be performed without a
7936 valid password, others can be performed if not listed here.
7938 To disable an action, set the password to "disable".
7939 To allow performing an action without a password, set the
7942 Use the keyword "all" to set the same password for all actions.
7945 cachemgr_passwd secret shutdown
7946 cachemgr_passwd lesssssssecret info stats/objects
7947 cachemgr_passwd disable all
7954 LOC: Config.onoff.client_db
7956 If you want to disable collecting per-client statistics,
7957 turn off client_db here.
7960 NAME: refresh_all_ims
7964 LOC: Config.onoff.refresh_all_ims
7966 When you enable this option, squid will always check
7967 the origin server for an update when a client sends an
7968 If-Modified-Since request. Many browsers use IMS
7969 requests when the user requests a reload, and this
7970 ensures those clients receive the latest version.
7972 By default (off), squid may return a Not Modified response
7973 based on the age of the cached version.
7976 NAME: reload_into_ims
7977 IFDEF: USE_HTTP_VIOLATIONS
7981 LOC: Config.onoff.reload_into_ims
7983 When you enable this option, client no-cache or ``reload''
7984 requests will be changed to If-Modified-Since requests.
7985 Doing this VIOLATES the HTTP standard. Enabling this
7986 feature could make you liable for problems which it
7989 see also refresh_pattern for a more selective approach.
7992 NAME: connect_retries
7994 LOC: Config.connect_retries
7997 This sets the maximum number of connection attempts made for each
7998 TCP connection. The connect_retries attempts must all still
7999 complete within the connection timeout period.
8001 The default is not to re-try if the first connection attempt fails.
8002 The (not recommended) maximum is 10 tries.
8004 A warning message will be generated if it is set to a too-high
8005 value and the configured value will be over-ridden.
8007 Note: These re-tries are in addition to forward_max_tries
8008 which limit how many different addresses may be tried to find
8012 NAME: retry_on_error
8014 LOC: Config.retry.onerror
8017 If set to ON Squid will automatically retry requests when
8018 receiving an error response with status 403 (Forbidden),
8019 500 (Internal Error), 501 or 503 (Service not available).
8020 Status 502 and 504 (Gateway errors) are always retried.
8022 This is mainly useful if you are in a complex cache hierarchy to
8023 work around access control errors.
8025 NOTE: This retry will attempt to find another working destination.
8026 Which is different from the server which just failed.
8029 NAME: as_whois_server
8031 LOC: Config.as_whois_server
8032 DEFAULT: whois.ra.net
8034 WHOIS server to query for AS numbers. NOTE: AS numbers are
8035 queried only when Squid starts up, not for every request.
8040 LOC: Config.onoff.offline
8043 Enable this option and Squid will never try to validate cached
8047 NAME: uri_whitespace
8048 TYPE: uri_whitespace
8049 LOC: Config.uri_whitespace
8052 What to do with requests that have whitespace characters in the
8055 strip: The whitespace characters are stripped out of the URL.
8056 This is the behavior recommended by RFC2396.
8057 deny: The request is denied. The user receives an "Invalid
8059 allow: The request is allowed and the URI is not changed. The
8060 whitespace characters remain in the URI. Note the
8061 whitespace is passed to redirector processes if they
8063 encode: The request is allowed and the whitespace characters are
8064 encoded according to RFC1738. This could be considered
8065 a violation of the HTTP/1.1
8066 RFC because proxies are not allowed to rewrite URI's.
8067 chop: The request is allowed and the URI is chopped at the
8068 first whitespace. This might also be considered a
8074 LOC: Config.chroot_dir
8077 Specifies a directory where Squid should do a chroot() while
8078 initializing. This also causes Squid to fully drop root
8079 privileges after initializing. This means, for example, if you
8080 use a HTTP port less than 1024 and try to reconfigure, you may
8081 get an error saying that Squid can not open the port.
8084 NAME: balance_on_multiple_ip
8086 LOC: Config.onoff.balance_on_multiple_ip
8089 Modern IP resolvers in squid sort lookup results by preferred access.
8090 By default squid will use these IP in order and only rotates to
8091 the next listed when the most preffered fails.
8093 Some load balancing servers based on round robin DNS have been
8094 found not to preserve user session state across requests
8095 to different IP addresses.
8097 Enabling this directive Squid rotates IP's per request.
8100 NAME: pipeline_prefetch
8102 LOC: Config.onoff.pipeline_prefetch
8105 To boost the performance of pipelined requests to closer
8106 match that of a non-proxied environment Squid can try to fetch
8107 up to two requests in parallel from a pipeline.
8109 Defaults to off for bandwidth management and access logging
8112 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
8115 NAME: high_response_time_warning
8118 LOC: Config.warnings.high_rptm
8121 If the one-minute median response time exceeds this value,
8122 Squid prints a WARNING with debug level 0 to get the
8123 administrators attention. The value is in milliseconds.
8126 NAME: high_page_fault_warning
8128 LOC: Config.warnings.high_pf
8131 If the one-minute average page fault rate exceeds this
8132 value, Squid prints a WARNING with debug level 0 to get
8133 the administrators attention. The value is in page faults
8137 NAME: high_memory_warning
8139 LOC: Config.warnings.high_memory
8142 If the memory usage (as determined by mallinfo) exceeds
8143 this amount, Squid prints a WARNING with debug level 0 to get
8144 the administrators attention.
8147 NAME: sleep_after_fork
8148 COMMENT: (microseconds)
8150 LOC: Config.sleep_after_fork
8153 When this is set to a non-zero value, the main Squid process
8154 sleeps the specified number of microseconds after a fork()
8155 system call. This sleep may help the situation where your
8156 system reports fork() failures due to lack of (virtual)
8157 memory. Note, however, if you have a lot of child
8158 processes, these sleep delays will add up and your
8159 Squid will not service requests for some amount of time
8160 until all the child processes have been started.
8161 On Windows value less then 1000 (1 milliseconds) are
8165 NAME: windows_ipaddrchangemonitor
8166 IFDEF: _SQUID_WINDOWS_
8170 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
8172 On Windows Squid by default will monitor IP address changes and will
8173 reconfigure itself after any detected event. This is very useful for
8174 proxies connected to internet with dial-up interfaces.
8175 In some cases (a Proxy server acting as VPN gateway is one) it could be
8176 desiderable to disable this behaviour setting this to 'off'.
8177 Note: after changing this, Squid service must be restarted.
8182 IFDEF: USE_SQUID_EUI
8184 LOC: Eui::TheConfig.euiLookup
8186 Whether to lookup the EUI or MAC address of a connected client.
8189 NAME: max_filedescriptors max_filedesc
8192 LOC: Config.max_filedescriptors
8194 The maximum number of filedescriptors supported.
8196 The default "0" means Squid inherits the current ulimit setting.
8198 Note: Changing this requires a restart of Squid. Also
8199 not all comm loops supports large values.
8207 Number of main Squid processes or "workers" to fork and maintain.
8208 0: "no daemon" mode, like running "squid -N ..."
8209 1: "no SMP" mode, start one main Squid process daemon (default)
8210 N: start N main Squid process daemons (i.e., SMP mode)
8212 In SMP mode, each worker does nearly all what a single Squid daemon
8213 does (e.g., listen on http_port and forward HTTP requests).
8216 NAME: cpu_affinity_map
8217 TYPE: CpuAffinityMap
8218 LOC: Config.cpuAffinityMap
8221 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
8223 Sets 1:1 mapping between Squid processes and CPU cores. For example,
8225 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
8227 affects processes 1 through 4 only and places them on the first
8228 four even cores, starting with core #1.
8230 CPU cores are numbered starting from 1. Requires support for
8231 sched_getaffinity(2) and sched_setaffinity(2) system calls.
8233 Multiple cpu_affinity_map options are merged.