2 # SQUID Web Proxy Cache http://www.squid-cache.org/
3 # ----------------------------------------------------------
5 # Squid is the result of efforts by numerous individuals from
6 # the Internet community; see the CONTRIBUTORS file for full
7 # details. Many organizations have provided support for Squid's
8 # development; see the SPONSORS file for full details. Squid is
9 # Copyrighted (C) 2000 by the Regents of the University of
10 # California; see the COPYRIGHT file for full details. Squid
11 # incorporates software developed and/or copyrighted by other
12 # sources; see the CREDITS file for full details.
14 # This program is free software; you can redistribute it and/or modify
15 # it under the terms of the GNU General Public License as published by
16 # the Free Software Foundation; either version 2 of the License, or
17 # (at your option) any later version.
19 # This program is distributed in the hope that it will be useful,
20 # but WITHOUT ANY WARRANTY; without even the implied warranty of
21 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 # GNU General Public License for more details.
24 # You should have received a copy of the GNU General Public License
25 # along with this program; if not, write to the Free Software
26 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
31 ----------------------------
33 This is the documentation for the Squid configuration file.
34 This documentation can also be found online at:
35 http://www.squid-cache.org/Doc/config/
37 You may wish to look at the Squid home page and wiki for the
38 FAQ and other documentation:
39 http://www.squid-cache.org/
40 http://wiki.squid-cache.org/SquidFaq
41 http://wiki.squid-cache.org/ConfigExamples
43 This documentation shows what the defaults for various directives
44 happen to be. If you don't need to change the default, you should
45 leave the line out of your squid.conf in most cases.
47 In some cases "none" refers to no default setting at all,
48 while in other cases it refers to the value of the option
49 - the comments for that keyword indicate if this is the case.
54 Configuration options can be included using the "include" directive.
55 Include takes a list of files to include. Quoting and wildcards are
60 include /path/to/included/file/squid.acl.config
62 Includes can be nested up to a hard-coded depth of 16 levels.
63 This arbitrary restriction is to prevent recursive include references
64 from causing Squid entering an infinite loop whilst trying to load
68 Conditional configuration
70 If-statements can be used to make configuration directives
74 ... regular configuration directives ...
76 ... regular configuration directives ...]
79 The else part is optional. The keywords "if", "else", and "endif"
80 must be typed on their own lines, as if they were regular
81 configuration directives.
83 NOTE: An else-if condition is not supported.
85 These individual conditions types are supported:
88 Always evaluates to true.
90 Always evaluates to false.
92 Equality comparison of two integer numbers.
97 The following SMP-related preprocessor macros can be used.
99 ${process_name} expands to the current Squid process "name"
100 (e.g., squid1, squid2, or cache1).
102 ${process_number} expands to the current Squid process
103 identifier, which is an integer number (e.g., 1, 2, 3) unique
104 across all Squid processes.
107 # Options Removed in 3.2
108 NAME: ignore_expect_100
111 Remove this line. The HTTP/1.1 feature is now fully supported by default.
114 NAME: dns_v4_fallback
123 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
126 NAME: url_rewrite_concurrency
129 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
132 # Options Removed in 3.1
136 Remove this line. DNS is no longer tested on startup.
139 NAME: extension_methods
142 Remove this line. All valid methods for HTTP are accepted by default.
145 # 2.7 Options Removed/Replaced in 3.1
153 Remove this line. HTTP/1.1 is supported by default.
156 NAME: upgrade_http0.9
159 Remove this line. ICY/1.0 streaming protocol is supported by default.
162 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
165 Alter these entries. Use the qos_flows directive instead.
168 # Options Removed in 3.0
172 Since squid-3.0 replace with request_header_access or reply_header_access
173 depending on whether you wish to match client requests or server replies.
176 NAME: httpd_accel_no_pmtu_disc
179 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
183 OPTIONS FOR AUTHENTICATION
184 -----------------------------------------------------------------------------
193 This is used to define parameters for the various authentication
194 schemes supported by Squid.
196 format: auth_param scheme parameter [setting]
198 The order in which authentication schemes are presented to the client is
199 dependent on the order the scheme first appears in config file. IE
200 has a bug (it's not RFC 2617 compliant) in that it will use the basic
201 scheme if basic is the first entry presented, even if more secure
202 schemes are presented. For now use the order in the recommended
203 settings section below. If other browsers have difficulties (don't
204 recognize the schemes offered even if you are using basic) either
205 put basic first, or disable the other schemes (by commenting out their
208 Once an authentication scheme is fully configured, it can only be
209 shutdown by shutting squid down and restarting. Changes can be made on
210 the fly and activated with a reconfigure. I.E. You can change to a
211 different helper, but not unconfigure the helper completely.
213 Please note that while this directive defines how Squid processes
214 authentication it does not automatically activate authentication.
215 To use authentication you must in addition make use of ACLs based
216 on login name in http_access (proxy_auth, proxy_auth_regex or
217 external with %LOGIN used in the format tag). The browser will be
218 challenged for authentication on the first such acl encountered
219 in http_access processing and will also be re-challenged for new
220 login credentials if the request is being denied by a proxy_auth
223 WARNING: authentication can't be used in a transparently intercepting
224 proxy as the client then thinks it is talking to an origin server and
225 not the proxy. This is a limitation of bending the TCP/IP protocol to
226 transparently intercepting port 80, not a limitation in Squid.
227 Ports flagged 'transparent', 'intercept', or 'tproxy' have
228 authentication disabled.
230 === Parameters for the basic scheme follow. ===
233 Specify the command for the external authenticator. Such a program
234 reads a line containing "username password" and replies "OK" or
235 "ERR" in an endless loop. "ERR" responses may optionally be followed
236 by a error description available as %m in the returned error page.
237 If you use an authenticator, make sure you have 1 acl of type
240 By default, the basic authentication scheme is not used unless a
241 program is specified.
243 If you want to use the traditional NCSA proxy authentication, set
244 this line to something like
246 auth_param basic program @DEFAULT_PREFIX@/libexec/ncsa_auth @DEFAULT_PREFIX@/etc/passwd
249 HTTP uses iso-latin-1 as characterset, while some authentication
250 backends such as LDAP expects UTF-8. If this is set to on Squid will
251 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
252 username & password to the helper.
254 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
255 The maximum number of authenticator processes to spawn. If you start too few
256 Squid will have to wait for them to process a backlog of credential
257 verifications, slowing it down. When password verifications are
258 done via a (slow) network you are likely to need lots of
259 authenticator processes.
261 The startup= and idle= options permit some skew in the exact amount
262 run. A minimum of startup=N will begin during startup and reconfigure.
263 Squid will start more in groups of up to idle=N in an attempt to meet
264 traffic needs and to keep idle=N free above those traffic needs up to
267 The concurrency= option sets the number of concurrent requests the
268 helper can process. The default of 0 is used for helpers who only
269 supports one request at a time. Setting this to a number greater than
270 0 changes the protocol used to include a channel number first on the
271 request/response line, allowing multiple requests to be sent to the
272 same helper in parallell without wating for the response.
273 Must not be set unless it's known the helper supports this.
275 auth_param basic children 20 startup=0 idle=1
278 Specifies the realm name which is to be reported to the
279 client for the basic proxy authentication scheme (part of
280 the text the user will see when prompted their username and
281 password). There is no default.
282 auth_param basic realm Squid proxy-caching web server
284 "credentialsttl" timetolive
285 Specifies how long squid assumes an externally validated
286 username:password pair is valid for - in other words how
287 often the helper program is called for that user. Set this
288 low to force revalidation with short lived passwords. Note
289 setting this high does not impact your susceptibility
290 to replay attacks unless you are using an one-time password
291 system (such as SecureID). If you are using such a system,
292 you will be vulnerable to replay attacks unless you also
293 use the max_user_ip ACL in an http_access rule.
295 "casesensitive" on|off
296 Specifies if usernames are case sensitive. Most user databases are
297 case insensitive allowing the same username to be spelled using both
298 lower and upper case letters, but some are case sensitive. This
299 makes a big difference for user_max_ip ACL processing and similar.
300 auth_param basic casesensitive off
302 === Parameters for the digest scheme follow ===
305 Specify the command for the external authenticator. Such
306 a program reads a line containing "username":"realm" and
307 replies with the appropriate H(A1) value hex encoded or
308 ERR if the user (or his H(A1) hash) does not exists.
309 See rfc 2616 for the definition of H(A1).
310 "ERR" responses may optionally be followed by a error description
311 available as %m in the returned error page.
313 By default, the digest authentication scheme is not used unless a
314 program is specified.
316 If you want to use a digest authenticator, set this line to
319 auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass
322 HTTP uses iso-latin-1 as characterset, while some authentication
323 backends such as LDAP expects UTF-8. If this is set to on Squid will
324 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
325 username & password to the helper.
327 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
328 The maximum number of authenticator processes to spawn (default 5).
329 If you start too few Squid will have to wait for them to
330 process a backlog of H(A1) calculations, slowing it down.
331 When the H(A1) calculations are done via a (slow) network
332 you are likely to need lots of authenticator processes.
334 The startup= and idle= options permit some skew in the exact amount
335 run. A minimum of startup=N will begin during startup and reconfigure.
336 Squid will start more in groups of up to idle=N in an attempt to meet
337 traffic needs and to keep idle=N free above those traffic needs up to
340 The concurrency= option sets the number of concurrent requests the
341 helper can process. The default of 0 is used for helpers who only
342 supports one request at a time. Setting this to a number greater than
343 0 changes the protocol used to include a channel number first on the
344 request/response line, allowing multiple requests to be sent to the
345 same helper in parallell without wating for the response.
346 Must not be set unless it's known the helper supports this.
348 auth_param digest children 20 startup=0 idle=1
351 Specifies the realm name which is to be reported to the
352 client for the digest proxy authentication scheme (part of
353 the text the user will see when prompted their username and
354 password). There is no default.
355 auth_param digest realm Squid proxy-caching web server
357 "nonce_garbage_interval" timeinterval
358 Specifies the interval that nonces that have been issued
359 to client_agent's are checked for validity.
361 "nonce_max_duration" timeinterval
362 Specifies the maximum length of time a given nonce will be
365 "nonce_max_count" number
366 Specifies the maximum number of times a given nonce can be
369 "nonce_strictness" on|off
370 Determines if squid requires strict increment-by-1 behavior
371 for nonce counts, or just incrementing (off - for use when
372 useragents generate nonce counts that occasionally miss 1
373 (ie, 1,2,4,6)). Default off.
375 "check_nonce_count" on|off
376 This directive if set to off can disable the nonce count check
377 completely to work around buggy digest qop implementations in
378 certain mainstream browser versions. Default on to check the
379 nonce count to protect from authentication replay attacks.
381 "post_workaround" on|off
382 This is a workaround to certain buggy browsers who sends
383 an incorrect request digest in POST requests when reusing
384 the same nonce as acquired earlier on a GET request.
386 === NTLM scheme options follow ===
389 Specify the command for the external NTLM authenticator.
390 Such a program reads exchanged NTLMSSP packets with
391 the browser via Squid until authentication is completed.
392 If you use an NTLM authenticator, make sure you have 1 acl
393 of type proxy_auth. By default, the NTLM authenticator_program
396 auth_param ntlm program @DEFAULT_PREFIX@/bin/ntlm_auth
398 "children" numberofchildren [startup=N] [idle=N]
399 The maximum number of authenticator processes to spawn (default 5).
400 If you start too few Squid will have to wait for them to
401 process a backlog of credential verifications, slowing it
402 down. When credential verifications are done via a (slow)
403 network you are likely to need lots of authenticator
406 The startup= and idle= options permit some skew in the exact amount
407 run. A minimum of startup=N will begin during startup and reconfigure.
408 Squid will start more in groups of up to idle=N in an attempt to meet
409 traffic needs and to keep idle=N free above those traffic needs up to
412 auth_param ntlm children 20 startup=0 idle=1
415 If you experience problems with PUT/POST requests when using the
416 Negotiate authentication scheme then you can try setting this to
417 off. This will cause Squid to forcibly close the connection on
418 the initial requests where the browser asks which schemes are
419 supported by the proxy.
421 auth_param ntlm keep_alive on
423 === Options for configuring the NEGOTIATE auth-scheme follow ===
426 Specify the command for the external Negotiate authenticator.
427 This protocol is used in Microsoft Active-Directory enabled setups with
428 the Microsoft Internet Explorer or Mozilla Firefox browsers.
429 Its main purpose is to exchange credentials with the Squid proxy
430 using the Kerberos mechanisms.
431 If you use a Negotiate authenticator, make sure you have at least
432 one acl of type proxy_auth active. By default, the negotiate
433 authenticator_program is not used.
434 The only supported program for this role is the ntlm_auth
435 program distributed as part of Samba, version 4 or later.
437 auth_param negotiate program @DEFAULT_PREFIX@/bin/ntlm_auth --helper-protocol=gss-spnego
439 "children" numberofchildren [startup=N] [idle=N]
440 The maximum number of authenticator processes to spawn (default 5).
441 If you start too few Squid will have to wait for them to
442 process a backlog of credential verifications, slowing it
443 down. When crendential verifications are done via a (slow)
444 network you are likely to need lots of authenticator
447 The startup= and idle= options permit some skew in the exact amount
448 run. A minimum of startup=N will begin during startup and reconfigure.
449 Squid will start more in groups of up to idle=N in an attempt to meet
450 traffic needs and to keep idle=N free above those traffic needs up to
453 auth_param negotiate children 20 startup=0 idle=1
456 If you experience problems with PUT/POST requests when using the
457 Negotiate authentication scheme then you can try setting this to
458 off. This will cause Squid to forcibly close the connection on
459 the initial requests where the browser asks which schemes are
460 supported by the proxy.
462 auth_param negotiate keep_alive on
467 #Recommended minimum configuration per scheme:
468 #auth_param negotiate program <uncomment and complete this line to activate>
469 #auth_param negotiate children 20 startup=0 idle=1
470 #auth_param negotiate keep_alive on
472 #auth_param ntlm program <uncomment and complete this line to activate>
473 #auth_param ntlm children 20 startup=0 idle=1
474 #auth_param ntlm keep_alive on
476 #auth_param digest program <uncomment and complete this line>
477 #auth_param digest children 20 startup=0 idle=1
478 #auth_param digest realm Squid proxy-caching web server
479 #auth_param digest nonce_garbage_interval 5 minutes
480 #auth_param digest nonce_max_duration 30 minutes
481 #auth_param digest nonce_max_count 50
483 #auth_param basic program <uncomment and complete this line>
484 #auth_param basic children 5 startup=5 idle=1
485 #auth_param basic realm Squid proxy-caching web server
486 #auth_param basic credentialsttl 2 hours
489 NAME: authenticate_cache_garbage_interval
492 LOC: Config.authenticateGCInterval
494 The time period between garbage collection across the username cache.
495 This is a tradeoff between memory utilization (long intervals - say
496 2 days) and CPU (short intervals - say 1 minute). Only change if you
500 NAME: authenticate_ttl
503 LOC: Config.authenticateTTL
505 The time a user & their credentials stay in the logged in
506 user cache since their last request. When the garbage
507 interval passes, all user credentials that have passed their
508 TTL are removed from memory.
511 NAME: authenticate_ip_ttl
513 LOC: Config.authenticateIpTTL
516 If you use proxy authentication and the 'max_user_ip' ACL,
517 this directive controls how long Squid remembers the IP
518 addresses associated with each user. Use a small value
519 (e.g., 60 seconds) if your users might change addresses
520 quickly, as is the case with dialups. You might be safe
521 using a larger value (e.g., 2 hours) in a corporate LAN
522 environment with relatively static address assignments.
527 -----------------------------------------------------------------------------
530 NAME: external_acl_type
531 TYPE: externalAclHelper
532 LOC: Config.externalAclHelperList
535 This option defines external acl classes using a helper program
536 to look up the status
538 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
542 ttl=n TTL in seconds for cached results (defaults to 3600
545 TTL for cached negative lookups (default same
548 Maximum number of acl helper processes spawned to service
549 external acl lookups of this type. (default 20)
551 Minimum number of acl helper processes to spawn during
552 startup and reconfigure to service external acl lookups
553 of this type. (default 0)
555 Number of acl helper processes to keep ahead of traffic
556 loads. Squid will spawn this many at once whenever load
557 rises above the capabilities of existing processes.
558 Up to the value of children-max. (default 1)
559 concurrency=n concurrency level per process. Only used with helpers
560 capable of processing more than one query at a time.
561 cache=n limit the result cache size, default is unbounded.
562 grace=n Percentage remaining of TTL where a refresh of a
563 cached entry should be initiated without needing to
564 wait for a new reply. (default is for no grace period)
565 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
566 ipv4 / ipv6 IP-mode used to communicate to this helper.
567 For compatability with older configurations and helpers
568 the default is currently 'ipv4'.
570 FORMAT specifications
572 %LOGIN Authenticated user login name
573 %EXT_USER Username from previous external acl
574 %EXT_LOG Log details from previous external acl
575 %EXT_TAG Tag from previous external acl
576 %IDENT Ident user name
578 %SRCPORT Client source port
581 %PROTO Requested protocol
583 %PATH Requested URL path
584 %METHOD Request method
585 %MYADDR Squid interface address
586 %MYPORT Squid http_port number
587 %PATH Requested URL-path (including query-string if any)
588 %USER_CERT SSL User certificate in PEM format
589 %USER_CERTCHAIN SSL User certificate chain in PEM format
590 %USER_CERT_xx SSL User certificate subject attribute xx
591 %USER_CA_xx SSL User certificate issuer attribute xx
593 %>{Header} HTTP request header "Header"
595 HTTP request header "Hdr" list member "member"
597 HTTP request header list member using ; as
598 list separator. ; can be any non-alphanumeric
601 %<{Header} HTTP reply header "Header"
603 HTTP reply header "Hdr" list member "member"
605 HTTP reply header list member using ; as
606 list separator. ; can be any non-alphanumeric
609 %% The percent sign. Useful for helpers which need
610 an unchanging input format.
612 In addition to the above, any string specified in the referencing
613 acl will also be included in the helper request line, after the
614 specified formats (see the "acl external" directive)
616 The helper receives lines per the above format specification,
617 and returns lines starting with OK or ERR indicating the validity
618 of the request and optionally followed by additional keywords with
621 General result syntax:
623 OK/ERR keyword=value ...
627 user= The users name (login)
628 password= The users password (for login= cache_peer option)
629 message= Message describing the reason. Available as %o
631 tag= Apply a tag to a request (for both ERR and OK results)
632 Only sets a tag, does not alter existing tags.
633 log= String to be logged in access.log. Available as
634 %ea in logformat specifications
636 If protocol=3.0 (the default) then URL escaping is used to protect
637 each value in both requests and responses.
639 If using protocol=2.5 then all values need to be enclosed in quotes
640 if they may contain whitespace, or the whitespace escaped using \.
641 And quotes or \ characters within the keyword value must be \ escaped.
643 When using the concurrency= option the protocol is changed by
644 introducing a query channel tag infront of the request/response.
645 The query channel tag is a number between 0 and concurrency-1.
652 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
653 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
654 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
655 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
656 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
659 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
660 DEFAULT: localhost src 127.0.0.1/32 ::1
661 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
662 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
664 Defining an Access List
666 Every access list definition must begin with an aclname and acltype,
667 followed by either type-specific arguments or a quoted filename that
670 acl aclname acltype argument ...
671 acl aclname acltype "file" ...
673 When using "file", the file should contain one item per line.
675 By default, regular expressions are CASE-SENSITIVE.
676 To make them case-insensitive, use the -i option. To return case-sensitive
677 use the +i option between patterns, or make a new ACL line without -i.
679 Some acl types require suspending the current request in order
680 to access some external data source.
681 Those which do are marked with the tag [slow], those which
682 don't are marked as [fast].
683 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
684 for further information
686 ***** ACL TYPES AVAILABLE *****
688 acl aclname src ip-address/mask ... # clients IP address [fast]
689 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
690 acl aclname dst ip-address/mask ... # URL host's IP address [slow]
691 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
693 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
694 # The arp ACL requires the special configure option --enable-arp-acl.
695 # Furthermore, the ARP ACL code is not portable to all operating systems.
696 # It works on Linux, Solaris, Windows, FreeBSD, and some
697 # other *BSD variants.
700 # NOTE: Squid can only determine the MAC address for clients that are on
701 # the same subnet. If the client is on a different subnet,
702 # then Squid cannot find out its MAC address.
704 acl aclname srcdomain .foo.com ...
705 # reverse lookup, from client IP [slow]
706 acl aclname dstdomain .foo.com ...
707 # Destination server from URL [fast]
708 acl aclname srcdom_regex [-i] \.foo\.com ...
709 # regex matching client name [slow]
710 acl aclname dstdom_regex [-i] \.foo\.com ...
711 # regex matching server [fast]
713 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
714 # based URL is used and no match is found. The name "none" is used
715 # if the reverse lookup fails.
717 acl aclname src_as number ...
718 acl aclname dst_as number ...
720 # Except for access control, AS numbers can be used for
721 # routing of requests to specific caches. Here's an
722 # example for routing all requests for AS#1241 and only
723 # those to mycache.mydomain.net:
724 # acl asexample dst_as 1241
725 # cache_peer_access mycache.mydomain.net allow asexample
726 # cache_peer_access mycache_mydomain.net deny all
728 acl aclname peername myPeer ...
730 # match against a named cache_peer entry
731 # set unique name= on cache_peer lines for reliable use.
733 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
743 # h1:m1 must be less than h2:m2
745 acl aclname url_regex [-i] ^http:// ...
746 # regex matching on whole URL [fast]
747 acl aclname urlpath_regex [-i] \.gif$ ...
748 # regex matching on URL path [fast]
750 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
752 acl aclname localport 3128 ... # TCP port the client connected to [fast]
753 # NP: for interception mode this is usually '80'
755 acl aclname myportname 3128 ... # http(s)_port name [fast]
757 acl aclname proto HTTP FTP ... # request protocol [fast]
759 acl aclname method GET POST ... # HTTP request method [fast]
761 acl aclname http_status 200 301 500- 400-403 ...
762 # status code in reply [fast]
764 acl aclname browser [-i] regexp ...
765 # pattern match on User-Agent header (see also req_header below) [fast]
767 acl aclname referer_regex [-i] regexp ...
768 # pattern match on Referer header [fast]
769 # Referer is highly unreliable, so use with care
771 acl aclname ident username ...
772 acl aclname ident_regex [-i] pattern ...
773 # string match on ident output [slow]
774 # use REQUIRED to accept any non-null ident.
776 acl aclname proxy_auth [-i] username ...
777 acl aclname proxy_auth_regex [-i] pattern ...
778 # perform http authentication challenge to the client and match against
779 # supplied credentials [slow]
781 # takes a list of allowed usernames.
782 # use REQUIRED to accept any valid username.
784 # Will use proxy authentication in forward-proxy scenarios, and plain
785 # http authenticaiton in reverse-proxy scenarios
787 # NOTE: when a Proxy-Authentication header is sent but it is not
788 # needed during ACL checking the username is NOT logged
791 # NOTE: proxy_auth requires a EXTERNAL authentication program
792 # to check username/password combinations (see
793 # auth_param directive).
795 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
796 # as the browser needs to be configured for using a proxy in order
797 # to respond to proxy authentication.
799 acl aclname snmp_community string ...
800 # A community string to limit access to your SNMP Agent [fast]
803 # acl snmppublic snmp_community public
805 acl aclname maxconn number
806 # This will be matched when the client's IP address has
807 # more than <number> TCP connections established. [fast]
808 # NOTE: This only measures direct TCP links so X-Forwarded-For
809 # indirect clients are not counted.
811 acl aclname max_user_ip [-s] number
812 # This will be matched when the user attempts to log in from more
813 # than <number> different ip addresses. The authenticate_ip_ttl
814 # parameter controls the timeout on the ip entries. [fast]
815 # If -s is specified the limit is strict, denying browsing
816 # from any further IP addresses until the ttl has expired. Without
817 # -s Squid will just annoy the user by "randomly" denying requests.
818 # (the counter is reset each time the limit is reached and a
820 # NOTE: in acceleration mode or where there is mesh of child proxies,
821 # clients may appear to come from multiple addresses if they are
822 # going through proxy farms, so a limit of 1 may cause user problems.
824 acl aclname random probability
825 # Pseudo-randomly match requests. Based on the probability given.
826 # Probability may be written as a decimal (0.333), fraction (1/3)
827 # or ratio of matches:non-matches (3:5).
829 acl aclname req_mime_type [-i] mime-type ...
830 # regex match against the mime type of the request generated
831 # by the client. Can be used to detect file upload or some
832 # types HTTP tunneling requests [fast]
833 # NOTE: This does NOT match the reply. You cannot use this
834 # to match the returned file type.
836 acl aclname req_header header-name [-i] any\.regex\.here
837 # regex match against any of the known request headers. May be
838 # thought of as a superset of "browser", "referer" and "mime-type"
841 acl aclname rep_mime_type [-i] mime-type ...
842 # regex match against the mime type of the reply received by
843 # squid. Can be used to detect file download or some
844 # types HTTP tunneling requests. [fast]
845 # NOTE: This has no effect in http_access rules. It only has
846 # effect in rules that affect the reply data stream such as
849 acl aclname rep_header header-name [-i] any\.regex\.here
850 # regex match against any of the known reply headers. May be
851 # thought of as a superset of "browser", "referer" and "mime-type"
854 acl aclname external class_name [arguments...]
855 # external ACL lookup via a helper class defined by the
856 # external_acl_type directive [slow]
858 acl aclname user_cert attribute values...
859 # match against attributes in a user SSL certificate
860 # attribute is one of DN/C/O/CN/L/ST [fast]
862 acl aclname ca_cert attribute values...
863 # match against attributes a users issuing CA SSL certificate
864 # attribute is one of DN/C/O/CN/L/ST [fast]
866 acl aclname ext_user username ...
867 acl aclname ext_user_regex [-i] pattern ...
868 # string match on username returned by external acl helper [slow]
869 # use REQUIRED to accept any non-null user name.
871 acl aclname tag tagvalue ...
872 # string match on tag returned by external acl helper [slow]
874 acl aclname hier_code codename ...
875 # string match against squid hierarchy code(s); [fast]
876 # e.g., DIRECT, PARENT_HIT, NONE, etc.
878 # NOTE: This has no effect in http_access rules. It only has
879 # effect in rules that affect the reply data stream such as
883 acl aclname ssl_error errorname
884 # match against SSL certificate validation error [fast]
885 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt template file
886 # The user aditionaly can use as error name the following error name
888 # [ssl::]certHasExpired: certificate "not after" field is in the past
889 # [ssl::]certNotYetValid: certificate "not before" field is in the
891 # [ssl::]certDomainMismatch: The certificate CN domain does not match
892 # connecting host name
893 # [ssl::]certUntrusted: The certificate is untrusted because of an
894 # error says that the certificate issuer is not trusted.
895 # [ssl::]certSelfSigned: The certificate is self signed
897 # The ssl::certHasExpired, ssl::certNotYetValid ssl::certDomainMismatch,
898 # ssl::certUntrusted and ssl::certSelfSigned also exists as predefined
901 # NOTE: The ssl_error acl has effect only when used with
902 # sslproxy_cert_error, sslproxy_cert_sign and sslproxy_cert_adapt
907 acl macaddress arp 09:00:2b:23:45:67
908 acl myexample dst_as 1241
909 acl password proxy_auth REQUIRED
910 acl fileupload req_mime_type -i ^multipart/form-data$
911 acl javascript rep_mime_type -i ^application/x-javascript$
915 # Recommended minimum configuration:
918 # Example rule allowing access from your local networks.
919 # Adapt to list your (internal) IP networks from where browsing
921 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
922 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
923 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
924 acl localnet src fc00::/7 # RFC 4193 local private network range
925 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
927 acl SSL_ports port 443
928 acl Safe_ports port 80 # http
929 acl Safe_ports port 21 # ftp
930 acl Safe_ports port 443 # https
931 acl Safe_ports port 70 # gopher
932 acl Safe_ports port 210 # wais
933 acl Safe_ports port 1025-65535 # unregistered ports
934 acl Safe_ports port 280 # http-mgmt
935 acl Safe_ports port 488 # gss-http
936 acl Safe_ports port 591 # filemaker
937 acl Safe_ports port 777 # multiling http
938 acl CONNECT method CONNECT
942 NAME: follow_x_forwarded_for
944 IFDEF: FOLLOW_X_FORWARDED_FOR
945 LOC: Config.accessList.followXFF
946 DEFAULT_IF_NONE: deny all
948 Allowing or Denying the X-Forwarded-For header to be followed to
949 find the original source of a request.
951 Requests may pass through a chain of several other proxies
952 before reaching us. The X-Forwarded-For header will contain a
953 comma-separated list of the IP addresses in the chain, with the
954 rightmost address being the most recent.
956 If a request reaches us from a source that is allowed by this
957 configuration item, then we consult the X-Forwarded-For header
958 to see where that host received the request from. If the
959 X-Forwarded-For header contains multiple addresses, we continue
960 backtracking until we reach an address for which we are not allowed
961 to follow the X-Forwarded-For header, or until we reach the first
962 address in the list. For the purpose of ACL used in the
963 follow_x_forwarded_for directive the src ACL type always matches
964 the address we are testing and srcdomain matches its rDNS.
966 The end result of this process is an IP address that we will
967 refer to as the indirect client address. This address may
968 be treated as the client address for access control, ICAP, delay
969 pools and logging, depending on the acl_uses_indirect_client,
970 icap_uses_indirect_client, delay_pool_uses_indirect_client,
971 log_uses_indirect_client and tproxy_uses_indirect_client options.
973 This clause only supports fast acl types.
974 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
976 SECURITY CONSIDERATIONS:
978 Any host for which we follow the X-Forwarded-For header
979 can place incorrect information in the header, and Squid
980 will use the incorrect information as if it were the
981 source address of the request. This may enable remote
982 hosts to bypass any access control restrictions that are
983 based on the client's source addresses.
987 acl localhost src 127.0.0.1
988 acl my_other_proxy srcdomain .proxy.example.com
989 follow_x_forwarded_for allow localhost
990 follow_x_forwarded_for allow my_other_proxy
993 NAME: acl_uses_indirect_client
996 IFDEF: FOLLOW_X_FORWARDED_FOR
998 LOC: Config.onoff.acl_uses_indirect_client
1000 Controls whether the indirect client address
1001 (see follow_x_forwarded_for) is used instead of the
1002 direct client address in acl matching.
1004 NOTE: maxconn ACL considers direct TCP links and indirect
1005 clients will always have zero. So no match.
1008 NAME: delay_pool_uses_indirect_client
1011 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1013 LOC: Config.onoff.delay_pool_uses_indirect_client
1015 Controls whether the indirect client address
1016 (see follow_x_forwarded_for) is used instead of the
1017 direct client address in delay pools.
1020 NAME: log_uses_indirect_client
1023 IFDEF: FOLLOW_X_FORWARDED_FOR
1025 LOC: Config.onoff.log_uses_indirect_client
1027 Controls whether the indirect client address
1028 (see follow_x_forwarded_for) is used instead of the
1029 direct client address in the access log.
1032 NAME: tproxy_uses_indirect_client
1035 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1037 LOC: Config.onoff.tproxy_uses_indirect_client
1039 Controls whether the indirect client address
1040 (see follow_x_forwarded_for) is used instead of the
1041 direct client address when spoofing the outgoing client.
1043 This has no effect on requests arriving in non-tproxy
1046 SECURITY WARNING: Usage of this option is dangerous
1047 and should not be used trivially. Correct configuration
1048 of follow_x_forewarded_for with a limited set of trusted
1049 sources is required to prevent abuse of your proxy.
1054 LOC: Config.accessList.http
1055 DEFAULT_IF_NONE: deny all
1057 Allowing or Denying access based on defined access lists
1059 Access to the HTTP port:
1060 http_access allow|deny [!]aclname ...
1062 NOTE on default values:
1064 If there are no "access" lines present, the default is to deny
1067 If none of the "access" lines cause a match, the default is the
1068 opposite of the last line in the list. If the last line was
1069 deny, the default is allow. Conversely, if the last line
1070 is allow, the default will be deny. For these reasons, it is a
1071 good idea to have an "deny all" entry at the end of your access
1072 lists to avoid potential confusion.
1074 This clause supports both fast and slow acl types.
1075 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1080 # Recommended minimum Access Permission configuration:
1082 # Only allow cachemgr access from localhost
1083 http_access allow localhost manager
1084 http_access deny manager
1086 # Deny requests to certain unsafe ports
1087 http_access deny !Safe_ports
1089 # Deny CONNECT to other than secure SSL ports
1090 http_access deny CONNECT !SSL_ports
1092 # We strongly recommend the following be uncommented to protect innocent
1093 # web applications running on the proxy server who think the only
1094 # one who can access services on "localhost" is a local user
1095 #http_access deny to_localhost
1098 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1101 # Example rule allowing access from your local networks.
1102 # Adapt localnet in the ACL section to list your (internal) IP networks
1103 # from where browsing should be allowed
1104 http_access allow localnet
1105 http_access allow localhost
1107 # And finally deny all other access to this proxy
1108 http_access deny all
1112 NAME: adapted_http_access http_access2
1114 LOC: Config.accessList.adapted_http
1117 Allowing or Denying access based on defined access lists
1119 Essentially identical to http_access, but runs after redirectors
1120 and ICAP/eCAP adaptation. Allowing access control based on their
1123 If not set then only http_access is used.
1126 NAME: http_reply_access
1128 LOC: Config.accessList.reply
1131 Allow replies to client requests. This is complementary to http_access.
1133 http_reply_access allow|deny [!] aclname ...
1135 NOTE: if there are no access lines present, the default is to allow
1138 If none of the access lines cause a match the opposite of the
1139 last line will apply. Thus it is good practice to end the rules
1140 with an "allow all" or "deny all" entry.
1142 This clause supports both fast and slow acl types.
1143 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1148 LOC: Config.accessList.icp
1149 DEFAULT_IF_NONE: deny all
1151 Allowing or Denying access to the ICP port based on defined
1154 icp_access allow|deny [!]aclname ...
1156 See http_access for details
1158 This clause only supports fast acl types.
1159 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1161 # Allow ICP queries from local networks only
1162 #icp_access allow localnet
1163 #icp_access deny all
1169 LOC: Config.accessList.htcp
1170 DEFAULT_IF_NONE: deny all
1172 Allowing or Denying access to the HTCP port based on defined
1175 htcp_access allow|deny [!]aclname ...
1177 See http_access for details
1179 NOTE: The default if no htcp_access lines are present is to
1180 deny all traffic. This default may cause problems with peers
1181 using the htcp option.
1183 This clause only supports fast acl types.
1184 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1186 # Allow HTCP queries from local networks only
1187 #htcp_access allow localnet
1188 #htcp_access deny all
1191 NAME: htcp_clr_access
1194 LOC: Config.accessList.htcp_clr
1195 DEFAULT_IF_NONE: deny all
1197 Allowing or Denying access to purge content using HTCP based
1198 on defined access lists
1200 htcp_clr_access allow|deny [!]aclname ...
1202 See http_access for details
1204 This clause only supports fast acl types.
1205 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1207 # Allow HTCP CLR requests from trusted peers
1208 acl htcp_clr_peer src 172.16.1.2
1209 htcp_clr_access allow htcp_clr_peer
1214 LOC: Config.accessList.miss
1217 Determins whether network access is permitted when satisfying a request.
1220 to force your neighbors to use you as a sibling instead of
1223 acl localclients src 172.16.0.0/16
1224 miss_access allow localclients
1225 miss_access deny !localclients
1227 This means only your local clients are allowed to fetch relayed/MISS
1228 replies from the network and all other clients can only fetch cached
1232 The default for this setting allows all clients who passed the
1233 http_access rules to relay via this proxy.
1235 This clause only supports fast acl types.
1236 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1239 NAME: ident_lookup_access
1242 DEFAULT_IF_NONE: deny all
1243 LOC: Ident::TheConfig.identLookup
1245 A list of ACL elements which, if matched, cause an ident
1246 (RFC 931) lookup to be performed for this request. For
1247 example, you might choose to always perform ident lookups
1248 for your main multi-user Unix boxes, but not for your Macs
1249 and PCs. By default, ident lookups are not performed for
1252 To enable ident lookups for specific client addresses, you
1253 can follow this example:
1255 acl ident_aware_hosts src 198.168.1.0/24
1256 ident_lookup_access allow ident_aware_hosts
1257 ident_lookup_access deny all
1259 Only src type ACL checks are fully supported. A srcdomain
1260 ACL might work at times, but it will not always provide
1263 This clause only supports fast acl types.
1264 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1267 NAME: reply_body_max_size
1268 COMMENT: size [acl acl...]
1271 LOC: Config.ReplyBodySize
1273 This option specifies the maximum size of a reply body. It can be
1274 used to prevent users from downloading very large files, such as
1275 MP3's and movies. When the reply headers are received, the
1276 reply_body_max_size lines are processed, and the first line where
1277 all (if any) listed ACLs are true is used as the maximum body size
1280 This size is checked twice. First when we get the reply headers,
1281 we check the content-length value. If the content length value exists
1282 and is larger than the allowed size, the request is denied and the
1283 user receives an error message that says "the request or reply
1284 is too large." If there is no content-length, and the reply
1285 size exceeds this limit, the client's connection is just closed
1286 and they will receive a partial reply.
1288 WARNING: downstream caches probably can not detect a partial reply
1289 if there is no content-length header, so they will cache
1290 partial responses and give them out as hits. You should NOT
1291 use this option if you have downstream caches.
1293 WARNING: A maximum size smaller than the size of squid's error messages
1294 will cause an infinite loop and crash squid. Ensure that the smallest
1295 non-zero value you use is greater that the maximum header size plus
1296 the size of your largest error page.
1298 If you set this parameter none (the default), there will be
1301 Configuration Format is:
1302 reply_body_max_size SIZE UNITS [acl ...]
1304 reply_body_max_size 10 MB
1310 -----------------------------------------------------------------------------
1313 NAME: http_port ascii_port
1314 TYPE: http_port_list
1316 LOC: Config.Sockaddr.http
1318 Usage: port [mode] [options]
1319 hostname:port [mode] [options]
1320 1.2.3.4:port [mode] [options]
1322 The socket addresses where Squid will listen for HTTP client
1323 requests. You may specify multiple socket addresses.
1324 There are three forms: port alone, hostname with port, and
1325 IP address with port. If you specify a hostname or IP
1326 address, Squid binds the socket to that specific
1327 address. Most likely, you do not need to bind to a specific
1328 address, so you can use the port number alone.
1330 If you are running Squid in accelerator mode, you
1331 probably want to listen on port 80 also, or instead.
1333 The -a command line option may be used to specify additional
1334 port(s) where Squid listens for proxy request. Such ports will
1335 be plain proxy ports with no options.
1337 You may specify multiple socket addresses on multiple lines.
1341 intercept Support for IP-Layer interception of
1342 outgoing requests without browser settings.
1343 NP: disables authentication and IPv6 on the port.
1345 tproxy Support Linux TPROXY for spoofing outgoing
1346 connections using the client IP address.
1347 NP: disables authentication and maybe IPv6 on the port.
1349 accel Accelerator / reverse proxy mode
1351 ssl-bump Intercept each CONNECT request matching ssl_bump ACL,
1352 establish secure connection with the client and with
1353 the server, decrypt HTTP messages as they pass through
1354 Squid, and treat them as unencrypted HTTP messages,
1355 becoming the man-in-the-middle.
1357 The ssl_bump option is required to fully enable
1358 the SslBump feature.
1360 Omitting the mode flag causes default forward proxy mode to be used.
1363 Accelerator Mode Options:
1365 defaultsite=domainname
1366 What to use for the Host: header if it is not present
1367 in a request. Determines what site (not origin server)
1368 accelerators should consider the default.
1370 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1372 protocol= Protocol to reconstruct accelerated requests with.
1373 Defaults to http for http_port and https for
1376 vport Virtual host port support. Using the http_port number
1377 instead of the port passed on Host: headers.
1379 vport=NN Virtual host port support. Using the specified port
1380 number instead of the port passed on Host: headers.
1383 Act as if this Squid is the origin server.
1384 This currently means generate new Date: and Expires:
1385 headers on HIT instead of adding Age:.
1387 ignore-cc Ignore request Cache-Control headers.
1389 WARNING: This option violates HTTP specifications if
1390 used in non-accelerator setups.
1392 allow-direct Allow direct forwarding in accelerator mode. Normally
1393 accelerated requests are denied direct forwarding as if
1394 never_direct was used.
1396 WARNING: this option opens accelerator mode to security
1397 vulnerabilities usually only affecting in interception
1398 mode. Make sure to protect forwarding with suitable
1399 http_access rules when using this.
1402 SSL Bump Mode Options:
1403 In addition to these options ssl-bump requires TLS/SSL options.
1405 generate-host-certificates[=<on|off>]
1406 Dynamically create SSL server certificates for the
1407 destination hosts of bumped CONNECT requests.When
1408 enabled, the cert and key options are used to sign
1409 generated certificates. Otherwise generated
1410 certificate will be selfsigned.
1411 If there is a CA certificate lifetime of the generated
1412 certificate equals lifetime of the CA certificate. If
1413 generated certificate is selfsigned lifetime is three
1415 This option is enabled by default when ssl-bump is used.
1416 See the ssl-bump option above for more information.
1418 dynamic_cert_mem_cache_size=SIZE
1419 Approximate total RAM size spent on cached generated
1420 certificates. If set to zero, caching is disabled. The
1421 default value is 4MB. An average XXX-bit certificate
1422 consumes about XXX bytes of RAM.
1426 cert= Path to SSL certificate (PEM format).
1428 key= Path to SSL private key file (PEM format)
1429 if not specified, the certificate file is
1430 assumed to be a combined certificate and
1433 version= The version of SSL/TLS supported
1434 1 automatic (default)
1439 cipher= Colon separated list of supported ciphers.
1440 NOTE: some ciphers such as EDH ciphers depend on
1441 additional settings. If those settings are
1442 omitted the ciphers may be silently ignored
1443 by the OpenSSL library.
1445 options= Various SSL implementation options. The most important
1447 NO_SSLv2 Disallow the use of SSLv2
1448 NO_SSLv3 Disallow the use of SSLv3
1449 NO_TLSv1 Disallow the use of TLSv1
1450 SINGLE_DH_USE Always create a new key when using
1451 temporary/ephemeral DH key exchanges
1452 ALL Enable various bug workarounds
1453 suggested as "harmless" by OpenSSL
1454 Be warned that this reduces SSL/TLS
1455 strength to some attacks.
1456 See OpenSSL SSL_CTX_set_options documentation for a
1457 complete list of options.
1459 clientca= File containing the list of CAs to use when
1460 requesting a client certificate.
1462 cafile= File containing additional CA certificates to
1463 use when verifying client certificates. If unset
1464 clientca will be used.
1466 capath= Directory containing additional CA certificates
1467 and CRL lists to use when verifying client certificates.
1469 crlfile= File of additional CRL lists to use when verifying
1470 the client certificate, in addition to CRLs stored in
1471 the capath. Implies VERIFY_CRL flag below.
1473 dhparams= File containing DH parameters for temporary/ephemeral
1474 DH key exchanges. See OpenSSL documentation for details
1475 on how to create this file.
1476 WARNING: EDH ciphers will be silently disabled if this
1479 sslflags= Various flags modifying the use of SSL:
1481 Don't request client certificates
1482 immediately, but wait until acl processing
1483 requires a certificate (not yet implemented).
1485 Don't use the default CA lists built in
1488 Don't allow for session reuse. Each connection
1489 will result in a new SSL session.
1491 Verify CRL lists when accepting client
1494 Verify CRL lists for all certificates in the
1495 client certificate chain.
1497 sslcontext= SSL session ID context identifier.
1501 connection-auth[=on|off]
1502 use connection-auth=off to tell Squid to prevent
1503 forwarding Microsoft connection oriented authentication
1504 (NTLM, Negotiate and Kerberos)
1506 disable-pmtu-discovery=
1507 Control Path-MTU discovery usage:
1508 off lets OS decide on what to do (default).
1509 transparent disable PMTU discovery when transparent
1511 always disable always PMTU discovery.
1513 In many setups of transparently intercepting proxies
1514 Path-MTU discovery can not work on traffic towards the
1515 clients. This is the case when the intercepting device
1516 does not fully track connections and fails to forward
1517 ICMP must fragment messages to the cache server. If you
1518 have such setup and experience that certain clients
1519 sporadically hang or never complete requests set
1520 disable-pmtu-discovery option to 'transparent'.
1522 name= Specifies a internal name for the port. Defaults to
1523 the port specification (port or addr:port)
1525 tcpkeepalive[=idle,interval,timeout]
1526 Enable TCP keepalive probes of idle connections.
1527 In seconds; idle is the initial time before TCP starts
1528 probing the connection, interval how often to probe, and
1529 timeout the time before giving up.
1531 If you run Squid on a dual-homed machine with an internal
1532 and an external interface we recommend you to specify the
1533 internal address:port in http_port. This way Squid will only be
1534 visible on the internal address.
1538 # Squid normally listens to port 3128
1539 http_port @DEFAULT_HTTP_PORT@
1545 TYPE: https_port_list
1547 LOC: Config.Sockaddr.https
1549 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1551 The socket address where Squid will listen for client requests made
1552 over TLS or SSL connections. Commonly referred to as HTTPS.
1554 This is most useful for situations where you are running squid in
1555 accelerator mode and you want to do the SSL work at the accelerator level.
1557 You may specify multiple socket addresses on multiple lines,
1558 each with their own SSL certificate and/or options.
1562 accel Accelerator / reverse proxy mode
1564 tproxy Support Linux TPROXY for spoofing outgoing
1565 connections using the client IP address.
1566 NP: disables authentication and maybe IPv6 on the port.
1568 ssl-bump Intercept each SSL request matching ssl_bump ACL,
1569 establish secure connection with the client and with
1570 the server, decrypt HTTP messages as they pass through
1571 Squid, and treat them as unencrypted HTTP messages,
1572 becoming the man-in-the-middle.
1574 The ssl_bump option is required to fully enable
1575 the SslBump feature.
1579 Omitting the mode flag causes default forward proxy mode to be used.
1582 See http_port for a list of generic options
1587 cert= Path to SSL certificate (PEM format).
1589 key= Path to SSL private key file (PEM format)
1590 if not specified, the certificate file is
1591 assumed to be a combined certificate and
1594 version= The version of SSL/TLS supported
1595 1 automatic (default)
1600 cipher= Colon separated list of supported ciphers.
1602 options= Various SSL engine options. The most important
1604 NO_SSLv2 Disallow the use of SSLv2
1605 NO_SSLv3 Disallow the use of SSLv3
1606 NO_TLSv1 Disallow the use of TLSv1
1607 SINGLE_DH_USE Always create a new key when using
1608 temporary/ephemeral DH key exchanges
1609 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1610 documentation for a complete list of options.
1612 clientca= File containing the list of CAs to use when
1613 requesting a client certificate.
1615 cafile= File containing additional CA certificates to
1616 use when verifying client certificates. If unset
1617 clientca will be used.
1619 capath= Directory containing additional CA certificates
1620 and CRL lists to use when verifying client certificates.
1622 crlfile= File of additional CRL lists to use when verifying
1623 the client certificate, in addition to CRLs stored in
1624 the capath. Implies VERIFY_CRL flag below.
1626 dhparams= File containing DH parameters for temporary/ephemeral
1629 sslflags= Various flags modifying the use of SSL:
1631 Don't request client certificates
1632 immediately, but wait until acl processing
1633 requires a certificate (not yet implemented).
1635 Don't use the default CA lists built in
1638 Don't allow for session reuse. Each connection
1639 will result in a new SSL session.
1641 Verify CRL lists when accepting client
1644 Verify CRL lists for all certificates in the
1645 client certificate chain.
1647 sslcontext= SSL session ID context identifier.
1649 generate-host-certificates[=<on|off>]
1650 Dynamically create SSL server certificates for the
1651 destination hosts of bumped SSL requests.When
1652 enabled, the cert and key options are used to sign
1653 generated certificates. Otherwise generated
1654 certificate will be selfsigned.
1655 If there is CA certificate life time of generated
1656 certificate equals lifetime of CA certificate. If
1657 generated certificate is selfsigned lifetime is three
1659 This option is enabled by default when SslBump is used.
1660 See the sslBump option above for more information.
1662 dynamic_cert_mem_cache_size=SIZE
1663 Approximate total RAM size spent on cached generated
1664 certificates. If set to zero, caching is disabled. The
1665 default value is 4MB. An average XXX-bit certificate
1666 consumes about XXX bytes of RAM.
1668 See http_port for a list of available options.
1671 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1674 LOC: Ip::Qos::TheConfig.tosToServer
1676 Allows you to select a TOS/Diffserv value for packets outgoing
1677 on the server side, based on an ACL.
1679 tcp_outgoing_tos ds-field [!]aclname ...
1681 Example where normal_service_net uses the TOS value 0x00
1682 and good_service_net uses 0x20
1684 acl normal_service_net src 10.0.0.0/24
1685 acl good_service_net src 10.0.1.0/24
1686 tcp_outgoing_tos 0x00 normal_service_net
1687 tcp_outgoing_tos 0x20 good_service_net
1689 TOS/DSCP values really only have local significance - so you should
1690 know what you're specifying. For more information, see RFC2474,
1691 RFC2475, and RFC3260.
1693 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1694 "default" to use whatever default your host has. Note that in
1695 practice often only multiples of 4 is usable as the two rightmost bits
1696 have been redefined for use by ECN (RFC 3168 section 23.1).
1698 Processing proceeds in the order specified, and stops at first fully
1702 NAME: clientside_tos
1705 LOC: Ip::Qos::TheConfig.tosToClient
1707 Allows you to select a TOS/Diffserv value for packets being transmitted
1708 on the client-side, based on an ACL.
1710 clientside_tos ds-field [!]aclname ...
1712 Example where normal_service_net uses the TOS value 0x00
1713 and good_service_net uses 0x20
1715 acl normal_service_net src 10.0.0.0/24
1716 acl good_service_net src 10.0.1.0/24
1717 clientside_tos 0x00 normal_service_net
1718 clientside_tos 0x20 good_service_net
1720 Note: This feature is incompatible with qos_flows. Any TOS values set here
1721 will be overwritten by TOS values in qos_flows.
1724 NAME: tcp_outgoing_mark
1726 IFDEF: SO_MARK&&USE_LIBCAP
1728 LOC: Ip::Qos::TheConfig.nfmarkToServer
1730 Allows you to apply a Netfilter mark value to outgoing packets
1731 on the server side, based on an ACL.
1733 tcp_outgoing_mark mark-value [!]aclname ...
1735 Example where normal_service_net uses the mark value 0x00
1736 and good_service_net uses 0x20
1738 acl normal_service_net src 10.0.0.0/24
1739 acl good_service_net src 10.0.1.0/24
1740 tcp_outgoing_mark 0x00 normal_service_net
1741 tcp_outgoing_mark 0x20 good_service_net
1744 NAME: clientside_mark
1746 IFDEF: SO_MARK&&USE_LIBCAP
1748 LOC: Ip::Qos::TheConfig.nfmarkToClient
1750 Allows you to apply a Netfilter mark value to packets being transmitted
1751 on the client-side, based on an ACL.
1753 clientside_mark mark-value [!]aclname ...
1755 Example where normal_service_net uses the mark value 0x00
1756 and good_service_net uses 0x20
1758 acl normal_service_net src 10.0.0.0/24
1759 acl good_service_net src 10.0.1.0/24
1760 clientside_mark 0x00 normal_service_net
1761 clientside_mark 0x20 good_service_net
1763 Note: This feature is incompatible with qos_flows. Any mark values set here
1764 will be overwritten by mark values in qos_flows.
1771 LOC: Ip::Qos::TheConfig
1773 Allows you to select a TOS/DSCP value to mark outgoing
1774 connections with, based on where the reply was sourced. For
1775 platforms using netfilter, allows you to set a netfilter mark
1776 value instead of, or in addition to, a TOS value.
1778 TOS values really only have local significance - so you should
1779 know what you're specifying. For more information, see RFC2474,
1780 RFC2475, and RFC3260.
1782 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1783 in practice often only multiples of 4 is usable as the two rightmost bits
1784 have been redefined for use by ECN (RFC 3168 section 23.1).
1786 Mark values can be any unsigned 32-bit integer value.
1788 This setting is configured by setting the following values:
1790 tos|mark Whether to set TOS or netfilter mark values
1792 local-hit=0xFF Value to mark local cache hits.
1794 sibling-hit=0xFF Value to mark hits from sibling peers.
1796 parent-hit=0xFF Value to mark hits from parent peers.
1798 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
1799 over the preserve-miss feature (see below), unless
1800 mask is specified, in which case only the bits
1801 specified in the mask are written.
1803 The TOS variant of the following features are only possible on Linux
1804 and require your kernel to be patched with the TOS preserving ZPH
1805 patch, available from http://zph.bratcheda.org
1806 No patch is needed to preserve the netfilter mark, which will work
1807 with all variants of netfilter.
1809 disable-preserve-miss
1810 This option disables the preservation of the TOS or netfilter
1811 mark. By default, the existing TOS or netfilter mark value of
1812 the response coming from the remote server will be retained
1813 and masked with miss-mark.
1814 NOTE: in the case of a netfilter mark, the mark must be set on
1815 the connection (using the CONNMARK target) not on the packet
1819 Allows you to mask certain bits in the TOS or mark value
1820 received from the remote server, before copying the value to
1821 the TOS sent towards clients.
1822 Default for tos: 0xFF (TOS from server is not changed).
1823 Default for mark: 0xFFFFFFFF (mark from server is not changed).
1825 All of these features require the --enable-zph-qos compilation flag
1826 (enabled by default). Netfilter marking also requires the
1827 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
1828 libcap 2.09+ (--with-libcap).
1832 NAME: tcp_outgoing_address
1835 LOC: Config.accessList.outgoing_address
1837 Allows you to map requests to different outgoing IP addresses
1838 based on the username or source address of the user making
1841 tcp_outgoing_address ipaddr [[!]aclname] ...
1844 Forwarding clients with dedicated IPs for certain subnets.
1846 acl normal_service_net src 10.0.0.0/24
1847 acl good_service_net src 10.0.2.0/24
1849 tcp_outgoing_address 2001:db8::c001 good_service_net
1850 tcp_outgoing_address 10.1.0.2 good_service_net
1852 tcp_outgoing_address 2001:db8::beef normal_service_net
1853 tcp_outgoing_address 10.1.0.1 normal_service_net
1855 tcp_outgoing_address 2001:db8::1
1856 tcp_outgoing_address 10.1.0.3
1858 Processing proceeds in the order specified, and stops at first fully
1861 Squid will add an implicit IP version test to each line.
1862 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
1863 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
1866 NOTE: The use of this directive using client dependent ACLs is
1867 incompatible with the use of server side persistent connections. To
1868 ensure correct results it is best to set server_persistent_connections
1869 to off when using this directive in such configurations.
1871 NOTE: The use of this directive to set a local IP on outgoing TCP links
1872 is incompatible with using TPROXY to set client IP out outbound TCP links.
1873 When needing to contact peers use the no-tproxy cache_peer option and the
1874 client_dst_passthru directive re-enable normal forwarding such as this.
1878 NAME: host_verify_strict
1881 LOC: Config.onoff.hostStrictVerify
1883 Regardless of this option setting, when dealing with intercepted
1884 traffic, Squid always verifies that the destination IP address matches
1885 the Host header domain or IP (called 'authority form URL').
1887 This enforcement is performed to satisfy a MUST-level requirement in
1888 RFC 2616 section 14.23: "The Host field value MUST represent the naming
1889 authority of the origin server or gateway given by the original URL".
1892 Squid always responds with an HTTP 409 (Conflict) error
1893 page and logs a security warning if there is no match.
1895 Squid verifies that the destination IP address matches
1896 the Host header for forward-proxy and reverse-proxy traffic
1897 as well. For those traffic types, Squid also enables the
1898 following checks, comparing the corresponding Host header
1899 and Request-URI components:
1901 * The host names (domain or IP) must be identical,
1902 but valueless or missing Host header disables all checks.
1903 For the two host names to match, both must be either IP
1906 * Port numbers must be identical, but if a port is missing
1907 the scheme-default port is assumed.
1910 When set to OFF (the default):
1911 Squid allows suspicious requests to continue but logs a
1912 security warning and blocks caching of the response.
1914 * Forward-proxy traffic is not checked at all.
1916 * Reverse-proxy traffic is not checked at all.
1918 * Intercepted traffic which passes verification is handled
1921 For now it also forces suspicious requests to go DIRECT to the
1922 original destination, overriding client_dst_passthru for
1923 intercepted requests which fail Host: verification.
1925 For now suspicious intercepted CONNECT requests are always
1926 responded to with an HTTP 409 (Conflict) error page.
1929 NAME: client_dst_passthru
1932 LOC: Config.onoff.client_dst_passthru
1934 With NAT or TPROXY intercepted traffic Squid may pass the request
1935 directly to the original client destination IP or seek a faster
1938 This option (on by default) prevents cache_peer and alternative DNS
1939 entries being used on intercepted traffic. Both of which lead to
1940 the security vulnerability outlined below.
1944 This directive should only be disabled if cache_peer are required.
1946 As described in CVE-2009-0801 when the Host: header alone is used
1947 to determine the destination of a request it becomes trivial for
1948 malicious scripts on remote websites to bypass browser same-origin
1949 security policy and sandboxing protections.
1951 The cause of this is that such applets are allowed to perform their
1952 own HTTP stack, in which case the same-origin policy of the browser
1953 sandbox only verifies that the applet tries to contact the same IP
1954 as from where it was loaded at the IP level. The Host: header may
1955 be different from the connected IP and approved origin.
1961 -----------------------------------------------------------------------------
1964 NAME: ssl_unclean_shutdown
1968 LOC: Config.SSL.unclean_shutdown
1970 Some browsers (especially MSIE) bugs out on SSL shutdown
1977 LOC: Config.SSL.ssl_engine
1980 The OpenSSL engine to use. You will need to set this if you
1981 would like to use hardware SSL acceleration for example.
1984 NAME: sslproxy_client_certificate
1987 LOC: Config.ssl_client.cert
1990 Client SSL Certificate to use when proxying https:// URLs
1993 NAME: sslproxy_client_key
1996 LOC: Config.ssl_client.key
1999 Client SSL Key to use when proxying https:// URLs
2002 NAME: sslproxy_version
2005 LOC: Config.ssl_client.version
2008 SSL version level to use when proxying https:// URLs
2011 NAME: sslproxy_options
2014 LOC: Config.ssl_client.options
2017 SSL implementation options to use when proxying https:// URLs
2019 The most important being:
2021 NO_SSLv2 Disallow the use of SSLv2
2022 NO_SSLv3 Disallow the use of SSLv3
2023 NO_TLSv1 Disallow the use of TLSv1
2025 Always create a new key when using temporary/ephemeral
2028 Disable use of RFC5077 session tickets. Some servers
2029 may have problems understanding the TLS extension due
2030 to ambiguous specification in RFC4507.
2031 ALL Enable various bug workarounds suggested as "harmless"
2032 by OpenSSL. Be warned that this may reduce SSL/TLS
2033 strength to some attacks.
2035 See the OpenSSL SSL_CTX_set_options documentation for a
2036 complete list of possible options.
2039 NAME: sslproxy_cipher
2042 LOC: Config.ssl_client.cipher
2045 SSL cipher list to use when proxying https:// URLs
2047 Colon separated list of supported ciphers.
2050 NAME: sslproxy_cafile
2053 LOC: Config.ssl_client.cafile
2056 file containing CA certificates to use when verifying server
2057 certificates while proxying https:// URLs
2060 NAME: sslproxy_capath
2063 LOC: Config.ssl_client.capath
2066 directory containing CA certificates to use when verifying
2067 server certificates while proxying https:// URLs
2073 LOC: Config.accessList.ssl_bump
2076 This ACL controls which CONNECT requests to an http_port
2077 marked with an sslBump flag are actually "bumped". Please
2078 see the sslBump flag of an http_port option for more details
2079 about decoding proxied SSL connections.
2081 By default, no requests are bumped.
2083 See also: http_port ssl-bump
2085 This clause supports both fast and slow acl types.
2086 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2089 # Example: Bump all requests except those originating from localhost and
2090 # those going to webax.com or example.com sites.
2092 acl localhost src 127.0.0.1/32
2093 acl broken_sites dstdomain .webax.com
2094 acl broken_sites dstdomain .example.com
2095 ssl_bump deny localhost
2096 ssl_bump deny broken_sites
2100 NAME: sslproxy_flags
2103 LOC: Config.ssl_client.flags
2106 Various flags modifying the use of SSL while proxying https:// URLs:
2107 DONT_VERIFY_PEER Accept certificates that fail verification.
2108 For refined control, see sslproxy_cert_error.
2109 NO_DEFAULT_CA Don't use the default CA list built in
2113 NAME: sslproxy_cert_error
2116 LOC: Config.ssl_client.cert_error
2119 Use this ACL to bypass server certificate validation errors.
2121 For example, the following lines will bypass all validation errors
2122 when talking to servers located at 172.16.0.0/16. All other
2123 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2125 acl BrokenServersAtTrustedIP dst 172.16.0.0/16
2126 sslproxy_cert_error allow BrokenServersAtTrustedIP
2127 sslproxy_cert_error deny all
2129 This clause only supports fast acl types.
2130 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2131 Using slow acl types may result in server crashes
2133 Without this option, all server certificate validation errors
2134 terminate the transaction. Bypassing validation errors is dangerous
2135 because an error usually implies that the server cannot be trusted and
2136 the connection may be insecure.
2138 See also: sslproxy_flags and DONT_VERIFY_PEER.
2140 Default setting: sslproxy_cert_error deny all
2143 NAME: sslproxy_cert_sign
2146 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2147 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2148 POSTSCRIPTUM: signTrusted all
2149 TYPE: sslproxy_cert_sign
2150 LOC: Config.ssl_client.cert_sign
2153 sslproxy_cert_sign <adaptation algorithm> acl ...
2155 The following certificate signing algorithms supported:
2157 the current signing algorithm using a configured CA certificate
2158 that is usually placed in and trusted by end-user browsers
2160 sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error
2162 sign using a self-signed certificate with the right CN to
2163 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2166 This clause only supports fast acl types.
2168 When the acl(s) match, the corresponding signing algorithm is used to
2169 generate the certificate. Otherwise, the default signing algorithm used
2171 BUG: The SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch ssl
2172 errors can not be used with ssl_error acl type.
2175 NAME: sslproxy_cert_adapt
2178 TYPE: sslproxy_cert_adapt
2179 LOC: Config.ssl_client.cert_adapt
2182 sslproxy_cert_adapt <adaptation algorithm> acl ...
2184 The following certificate adaptation algorithms supported:
2186 sets the "Not After" property to the "Not After" propery of
2187 the ca certificate used to sign generated certificates
2189 sets the "Not Before" property to the "Not Before" property of
2190 the ca certificate used to sign generated certificates
2192 sets certificate Subject.CN property to the
2193 host name from specified as a CN parameter (setCommonName{CN})
2194 or, if no explicit CN parameter was specified, extracted from
2195 the CONNECT request. It is a misconfiguration to use setName
2196 without an explicit parameter for intercepted or tproxied SSL
2199 This clause only supports fast acl types.
2201 When the acl(s) match, the corresponding adaptation algorithm is
2202 applied to the fake/generated certificate. Otherwise, the
2203 default mimicking action takes place.
2205 BUG: The SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch ssl
2206 errors can not be used with ssl_error acl type
2209 NAME: sslpassword_program
2212 LOC: Config.Program.ssl_password
2215 Specify a program used for entering SSL key passphrases
2216 when using encrypted SSL certificate keys. If not specified
2217 keys must either be unencrypted, or Squid started with the -N
2218 option to allow it to query interactively for the passphrase.
2220 The key file name is given as argument to the program allowing
2221 selection of the right password if you have multiple encrypted
2226 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2227 -----------------------------------------------------------------------------
2230 NAME: sslcrtd_program
2233 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2234 LOC: Ssl::TheConfig.ssl_crtd
2236 Specify the location and options of the executable for ssl_crtd process.
2237 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2238 For more information use:
2239 @DEFAULT_SSL_CRTD@ -h
2242 NAME: sslcrtd_children
2243 TYPE: HelperChildConfig
2245 DEFAULT: 32 startup=5 idle=1
2246 LOC: Ssl::TheConfig.ssl_crtdChildren
2248 The maximum number of processes spawn to service ssl server.
2249 The maximum this may be safely set to is 32.
2251 The startup= and idle= options allow some measure of skew in your
2256 Sets the minimum number of processes to spawn when Squid
2257 starts or reconfigures. When set to zero the first request will
2258 cause spawning of the first child process to handle it.
2260 Starting too few children temporary slows Squid under load while it
2261 tries to spawn enough additional processes to cope with traffic.
2265 Sets a minimum of how many processes Squid is to try and keep available
2266 at all times. When traffic begins to rise above what the existing
2267 processes can handle this many more will be spawned up to the maximum
2268 configured. A minimum setting of 1 is required.
2270 You must have at least one ssl_crtd process.
2274 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2275 -----------------------------------------------------------------------------
2283 To specify other caches in a hierarchy, use the format:
2285 cache_peer hostname type http-port icp-port [options]
2290 # hostname type port port options
2291 # -------------------- -------- ----- ----- -----------
2292 cache_peer parent.foo.net parent 3128 3130 default
2293 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2294 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2295 cache_peer example.com parent 80 0 default
2296 cache_peer cdn.example.com sibling 3128 0
2298 type: either 'parent', 'sibling', or 'multicast'.
2300 proxy-port: The port number where the peer accept HTTP requests.
2301 For other Squid proxies this is usually 3128
2302 For web servers this is usually 80
2304 icp-port: Used for querying neighbor caches about objects.
2305 Set to 0 if the peer does not support ICP or HTCP.
2306 See ICP and HTCP options below for additional details.
2309 ==== ICP OPTIONS ====
2311 You MUST also set icp_port and icp_access explicitly when using these options.
2312 The defaults will prevent peer traffic using ICP.
2315 no-query Disable ICP queries to this neighbor.
2318 Indicates the named peer is a member of a multicast group.
2319 ICP queries will not be sent directly to the peer, but ICP
2320 replies will be accepted from it.
2322 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2323 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2326 To only send ICP queries to this neighbor infrequently.
2327 This is used to keep the neighbor round trip time updated
2328 and is usually used in conjunction with weighted-round-robin.
2331 ==== HTCP OPTIONS ====
2333 You MUST also set htcp_port and htcp_access explicitly when using these options.
2334 The defaults will prevent peer traffic using HTCP.
2337 htcp Send HTCP, instead of ICP, queries to the neighbor.
2338 You probably also want to set the "icp-port" to 4827
2339 instead of 3130. This directive accepts a comma separated
2340 list of options described below.
2342 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2344 htcp=no-clr Send HTCP to the neighbor but without
2345 sending any CLR requests. This cannot be used with
2348 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2349 This cannot be used with no-clr.
2352 Send HTCP to the neighbor including CLRs but only when
2353 they do not result from PURGE requests.
2356 Forward any HTCP CLR requests this proxy receives to the peer.
2359 ==== PEER SELECTION METHODS ====
2361 The default peer selection method is ICP, with the first responding peer
2362 being used as source. These options can be used for better load balancing.
2365 default This is a parent cache which can be used as a "last-resort"
2366 if a peer cannot be located by any of the peer-selection methods.
2367 If specified more than once, only the first is used.
2369 round-robin Load-Balance parents which should be used in a round-robin
2370 fashion in the absence of any ICP queries.
2371 weight=N can be used to add bias.
2373 weighted-round-robin
2374 Load-Balance parents which should be used in a round-robin
2375 fashion with the frequency of each parent being based on the
2376 round trip time. Closer parents are used more often.
2377 Usually used for background-ping parents.
2378 weight=N can be used to add bias.
2380 carp Load-Balance parents which should be used as a CARP array.
2381 The requests will be distributed among the parents based on the
2382 CARP load balancing hash function based on their weight.
2384 userhash Load-balance parents based on the client proxy_auth or ident username.
2386 sourcehash Load-balance parents based on the client source IP.
2389 To be used only for cache peers of type "multicast".
2390 ALL members of this multicast group have "sibling"
2391 relationship with it, not "parent". This is to a multicast
2392 group when the requested object would be fetched only from
2393 a "parent" cache, anyway. It's useful, e.g., when
2394 configuring a pool of redundant Squid proxies, being
2395 members of the same multicast group.
2398 ==== PEER SELECTION OPTIONS ====
2400 weight=N use to affect the selection of a peer during any weighted
2401 peer-selection mechanisms.
2402 The weight must be an integer; default is 1,
2403 larger weights are favored more.
2404 This option does not affect parent selection if a peering
2405 protocol is not in use.
2407 basetime=N Specify a base amount to be subtracted from round trip
2409 It is subtracted before division by weight in calculating
2410 which parent to fectch from. If the rtt is less than the
2411 base time the rtt is set to a minimal value.
2413 ttl=N Specify a TTL to use when sending multicast ICP queries
2415 Only useful when sending to a multicast group.
2416 Because we don't accept ICP replies from random
2417 hosts, you must configure other group members as
2418 peers with the 'multicast-responder' option.
2420 no-delay To prevent access to this neighbor from influencing the
2423 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2424 enabled) for this host from the specified URL rather
2425 than the Squid default location.
2428 ==== CARP OPTIONS ====
2430 carp-key=key-specification
2431 use a different key than the full URL to hash against the peer.
2432 the key-specification is a comma-separated list of the keywords
2433 scheme, host, port, path, params
2434 Order is not important.
2436 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2438 originserver Causes this parent to be contacted as an origin server.
2439 Meant to be used in accelerator setups when the peer
2443 Set the Host header of requests forwarded to this peer.
2444 Useful in accelerator setups where the server (peer)
2445 expects a certain domain name but clients may request
2446 others. ie example.com or www.example.com
2448 no-digest Disable request of cache digests.
2451 Disables requesting ICMP RTT database (NetDB).
2454 ==== AUTHENTICATION OPTIONS ====
2457 If this is a personal/workgroup proxy and your parent
2458 requires proxy authentication.
2460 Note: The string can include URL escapes (i.e. %20 for
2461 spaces). This also means % must be written as %%.
2464 Send login details received from client to this peer.
2465 Both Proxy- and WWW-Authorization headers are passed
2466 without alteration to the peer.
2467 Authentication is not required by Squid for this to work.
2469 Note: This will pass any form of authentication but
2470 only Basic auth will work through a proxy unless the
2471 connection-auth options are also used.
2473 login=PASS Send login details received from client to this peer.
2474 Authentication is not required by this option.
2476 If there are no client-provided authentication headers
2477 to pass on, but username and password are available
2478 from an external ACL user= and password= result tags
2479 they may be sent instead.
2481 Note: To combine this with proxy_auth both proxies must
2482 share the same user database as HTTP only allows for
2483 a single login (one for proxy, one for origin server).
2484 Also be warned this will expose your users proxy
2485 password to the peer. USE WITH CAUTION
2488 Send the username to the upstream cache, but with a
2489 fixed password. This is meant to be used when the peer
2490 is in another administrative domain, but it is still
2491 needed to identify each user.
2492 The star can optionally be followed by some extra
2493 information which is added to the username. This can
2494 be used to identify this proxy to the peer, similar to
2495 the login=username:password option above.
2498 If this is a personal/workgroup proxy and your parent
2499 requires a secure proxy authentication.
2500 The first principal from the default keytab or defined by
2501 the environment variable KRB5_KTNAME will be used.
2503 WARNING: The connection may transmit requests from multiple
2504 clients. Negotiate often assumes end-to-end authentication
2505 and a single-client. Which is not strictly true here.
2507 login=NEGOTIATE:principal_name
2508 If this is a personal/workgroup proxy and your parent
2509 requires a secure proxy authentication.
2510 The principal principal_name from the default keytab or
2511 defined by the environment variable KRB5_KTNAME will be
2514 WARNING: The connection may transmit requests from multiple
2515 clients. Negotiate often assumes end-to-end authentication
2516 and a single-client. Which is not strictly true here.
2518 connection-auth=on|off
2519 Tell Squid that this peer does or not support Microsoft
2520 connection oriented authentication, and any such
2521 challenges received from there should be ignored.
2522 Default is auto to automatically determine the status
2526 ==== SSL / HTTPS / TLS OPTIONS ====
2528 ssl Encrypt connections to this peer with SSL/TLS.
2530 sslcert=/path/to/ssl/certificate
2531 A client SSL certificate to use when connecting to
2534 sslkey=/path/to/ssl/key
2535 The private SSL key corresponding to sslcert above.
2536 If 'sslkey' is not specified 'sslcert' is assumed to
2537 reference a combined file containing both the
2538 certificate and the key.
2541 The SSL version to use when connecting to this peer
2542 1 = automatic (default)
2547 sslcipher=... The list of valid SSL ciphers to use when connecting
2550 ssloptions=... Specify various SSL implementation options:
2552 NO_SSLv2 Disallow the use of SSLv2
2553 NO_SSLv3 Disallow the use of SSLv3
2554 NO_TLSv1 Disallow the use of TLSv1
2556 Always create a new key when using
2557 temporary/ephemeral DH key exchanges
2558 ALL Enable various bug workarounds
2559 suggested as "harmless" by OpenSSL
2560 Be warned that this reduces SSL/TLS
2561 strength to some attacks.
2563 See the OpenSSL SSL_CTX_set_options documentation for a
2566 sslcafile=... A file containing additional CA certificates to use
2567 when verifying the peer certificate.
2569 sslcapath=... A directory containing additional CA certificates to
2570 use when verifying the peer certificate.
2572 sslcrlfile=... A certificate revocation list file to use when
2573 verifying the peer certificate.
2575 sslflags=... Specify various flags modifying the SSL implementation:
2578 Accept certificates even if they fail to
2581 Don't use the default CA list built in
2584 Don't verify the peer certificate
2585 matches the server name
2587 ssldomain= The peer name as advertised in it's certificate.
2588 Used for verifying the correctness of the received peer
2589 certificate. If not specified the peer hostname will be
2593 Enable the "Front-End-Https: On" header needed when
2594 using Squid as a SSL frontend in front of Microsoft OWA.
2595 See MS KB document Q307347 for details on this header.
2596 If set to auto the header will only be added if the
2597 request is forwarded as a https:// URL.
2600 ==== GENERAL OPTIONS ====
2603 A peer-specific connect timeout.
2604 Also see the peer_connect_timeout directive.
2606 connect-fail-limit=N
2607 How many times connecting to a peer must fail before
2608 it is marked as down. Default is 10.
2610 allow-miss Disable Squid's use of only-if-cached when forwarding
2611 requests to siblings. This is primarily useful when
2612 icp_hit_stale is used by the sibling. To extensive use
2613 of this option may result in forwarding loops, and you
2614 should avoid having two-way peerings with this option.
2615 For example to deny peer usage on requests from peer
2616 by denying cache_peer_access if the source is a peer.
2618 max-conn=N Limit the amount of connections Squid may open to this
2621 name=xxx Unique name for the peer.
2622 Required if you have multiple peers on the same host
2623 but different ports.
2624 This name can be used in cache_peer_access and similar
2625 directives to dentify the peer.
2626 Can be used by outgoing access controls through the
2629 no-tproxy Do not use the client-spoof TPROXY support when forwarding
2630 requests to this peer. Use normal address selection instead.
2632 proxy-only objects fetched from the peer will not be stored locally.
2636 NAME: cache_peer_domain cache_host_domain
2641 Use to limit the domains for which a neighbor cache will be
2644 cache_peer_domain cache-host domain [domain ...]
2645 cache_peer_domain cache-host !domain
2647 For example, specifying
2649 cache_peer_domain parent.foo.net .edu
2651 has the effect such that UDP query packets are sent to
2652 'bigserver' only when the requested object exists on a
2653 server in the .edu domain. Prefixing the domainname
2654 with '!' means the cache will be queried for objects
2657 NOTE: * Any number of domains may be given for a cache-host,
2658 either on the same or separate lines.
2659 * When multiple domains are given for a particular
2660 cache-host, the first matched domain is applied.
2661 * Cache hosts with no domain restrictions are queried
2663 * There are no defaults.
2664 * There is also a 'cache_peer_access' tag in the ACL
2668 NAME: cache_peer_access
2673 Similar to 'cache_peer_domain' but provides more flexibility by
2676 cache_peer_access cache-host allow|deny [!]aclname ...
2678 The syntax is identical to 'http_access' and the other lists of
2679 ACL elements. See the comments for 'http_access' below, or
2680 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
2683 NAME: neighbor_type_domain
2684 TYPE: hostdomaintype
2688 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
2690 Modifying the neighbor type for specific domains is now
2691 possible. You can treat some domains differently than the
2692 default neighbor type specified on the 'cache_peer' line.
2693 Normally it should only be necessary to list domains which
2694 should be treated differently because the default neighbor type
2695 applies for hostnames which do not match domains listed here.
2698 cache_peer cache.foo.org parent 3128 3130
2699 neighbor_type_domain cache.foo.org sibling .com .net
2700 neighbor_type_domain cache.foo.org sibling .au .de
2703 NAME: dead_peer_timeout
2707 LOC: Config.Timeout.deadPeer
2709 This controls how long Squid waits to declare a peer cache
2710 as "dead." If there are no ICP replies received in this
2711 amount of time, Squid will declare the peer dead and not
2712 expect to receive any further ICP replies. However, it
2713 continues to send ICP queries, and will mark the peer as
2714 alive upon receipt of the first subsequent ICP reply.
2716 This timeout also affects when Squid expects to receive ICP
2717 replies from peers. If more than 'dead_peer' seconds have
2718 passed since the last ICP reply was received, Squid will not
2719 expect to receive an ICP reply on the next query. Thus, if
2720 your time between requests is greater than this timeout, you
2721 will see a lot of requests sent DIRECT to origin servers
2722 instead of to your parents.
2725 NAME: forward_max_tries
2728 LOC: Config.forward_max_tries
2730 Controls how many different forward paths Squid will try
2731 before giving up. See also forward_timeout.
2733 NOTE: connect_retries (default: none) can make each of these
2734 possible forwarding paths be tried multiple times.
2737 NAME: hierarchy_stoplist
2740 LOC: Config.hierarchy_stoplist
2742 A list of words which, if found in a URL, cause the object to
2743 be handled directly by this cache. In other words, use this
2744 to not query neighbor caches for certain objects. You may
2745 list this option multiple times.
2748 hierarchy_stoplist cgi-bin ?
2750 Note: never_direct overrides this option.
2754 MEMORY CACHE OPTIONS
2755 -----------------------------------------------------------------------------
2762 LOC: Config.memMaxSize
2764 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
2765 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
2766 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
2767 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
2769 'cache_mem' specifies the ideal amount of memory to be used
2771 * In-Transit objects
2773 * Negative-Cached objects
2775 Data for these objects are stored in 4 KB blocks. This
2776 parameter specifies the ideal upper limit on the total size of
2777 4 KB blocks allocated. In-Transit objects take the highest
2780 In-transit objects have priority over the others. When
2781 additional space is needed for incoming data, negative-cached
2782 and hot objects will be released. In other words, the
2783 negative-cached and hot objects will fill up any unused space
2784 not needed for in-transit objects.
2786 If circumstances require, this limit will be exceeded.
2787 Specifically, if your incoming request rate requires more than
2788 'cache_mem' of memory to hold in-transit objects, Squid will
2789 exceed this limit to satisfy the new requests. When the load
2790 decreases, blocks will be freed until the high-water mark is
2791 reached. Thereafter, blocks will be used to store hot
2794 If shared memory caching is enabled, Squid does not use the shared
2795 cache space for in-transit objects, but they still consume as much
2796 local memory as they need. For more details about the shared memory
2797 cache, see memory_cache_shared.
2800 NAME: maximum_object_size_in_memory
2804 LOC: Config.Store.maxInMemObjSize
2806 Objects greater than this size will not be attempted to kept in
2807 the memory cache. This should be set high enough to keep objects
2808 accessed frequently in memory to improve performance whilst low
2809 enough to keep larger objects from hoarding cache_mem.
2812 NAME: memory_cache_shared
2815 LOC: Config.memShared
2817 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
2819 Controls whether the memory cache is shared among SMP workers.
2821 The shared memory cache is meant to occupy cache_mem bytes and replace
2822 the non-shared memory cache, although some entities may still be
2823 cached locally by workers for now (e.g., internal and in-transit
2824 objects may be served from a local memory cache even if shared memory
2825 caching is enabled).
2827 By default, the memory cache is shared if and only if all of the
2828 following conditions are satisfied: Squid runs in SMP mode with
2829 multiple workers, cache_mem is positive, and Squid environment
2830 supports required IPC primitives (e.g., POSIX shared memory segments
2831 and GCC-style atomic operations).
2833 To avoid blocking locks, shared memory uses opportunistic algorithms
2834 that do not guarantee that every cachable entity that could have been
2835 shared among SMP workers will actually be shared.
2837 Currently, entities exceeding 32KB in size cannot be shared.
2840 NAME: memory_cache_mode
2845 Controls which objects to keep in the memory cache (cache_mem)
2847 always Keep most recently fetched objects in memory (default)
2849 disk Only disk cache hits are kept in memory, which means
2850 an object must first be cached on disk and then hit
2851 a second time before cached in memory.
2853 network Only objects fetched from network is kept in memory
2856 NAME: memory_replacement_policy
2858 LOC: Config.memPolicy
2861 The memory replacement policy parameter determines which
2862 objects are purged from memory when memory space is needed.
2864 See cache_replacement_policy for details.
2869 -----------------------------------------------------------------------------
2872 NAME: cache_replacement_policy
2874 LOC: Config.replPolicy
2877 The cache replacement policy parameter determines which
2878 objects are evicted (replaced) when disk space is needed.
2880 lru : Squid's original list based LRU policy
2881 heap GDSF : Greedy-Dual Size Frequency
2882 heap LFUDA: Least Frequently Used with Dynamic Aging
2883 heap LRU : LRU policy implemented using a heap
2885 Applies to any cache_dir lines listed below this.
2887 The LRU policies keeps recently referenced objects.
2889 The heap GDSF policy optimizes object hit rate by keeping smaller
2890 popular objects in cache so it has a better chance of getting a
2891 hit. It achieves a lower byte hit rate than LFUDA though since
2892 it evicts larger (possibly popular) objects.
2894 The heap LFUDA policy keeps popular objects in cache regardless of
2895 their size and thus optimizes byte hit rate at the expense of
2896 hit rate since one large, popular object will prevent many
2897 smaller, slightly less popular objects from being cached.
2899 Both policies utilize a dynamic aging mechanism that prevents
2900 cache pollution that can otherwise occur with frequency-based
2901 replacement policies.
2903 NOTE: if using the LFUDA replacement policy you should increase
2904 the value of maximum_object_size above its default of 4096 KB to
2905 to maximize the potential byte hit rate improvement of LFUDA.
2907 For more information about the GDSF and LFUDA cache replacement
2908 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
2909 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
2915 LOC: Config.cacheSwap
2919 cache_dir Type Directory-Name Fs-specific-data [options]
2921 You can specify multiple cache_dir lines to spread the
2922 cache among different disk partitions.
2924 Type specifies the kind of storage system to use. Only "ufs"
2925 is built by default. To enable any of the other storage systems
2926 see the --enable-storeio configure option.
2928 'Directory' is a top-level directory where cache swap
2929 files will be stored. If you want to use an entire disk
2930 for caching, this can be the mount-point directory.
2931 The directory must exist and be writable by the Squid
2932 process. Squid will NOT create this directory for you.
2934 In SMP configurations, cache_dir must not precede the workers option
2935 and should use configuration macros or conditionals to give each
2936 worker interested in disk caching a dedicated cache directory.
2940 "ufs" is the old well-known Squid storage format that has always
2943 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
2945 'Mbytes' is the amount of disk space (MB) to use under this
2946 directory. The default is 100 MB. Change this to suit your
2947 configuration. Do NOT put the size of your disk drive here.
2948 Instead, if you want Squid to use the entire disk drive,
2949 subtract 20% and use that value.
2951 'L1' is the number of first-level subdirectories which
2952 will be created under the 'Directory'. The default is 16.
2954 'L2' is the number of second-level subdirectories which
2955 will be created under each first-level directory. The default
2958 The aufs store type:
2960 "aufs" uses the same storage format as "ufs", utilizing
2961 POSIX-threads to avoid blocking the main Squid process on
2962 disk-I/O. This was formerly known in Squid as async-io.
2964 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
2966 see argument descriptions under ufs above
2968 The diskd store type:
2970 "diskd" uses the same storage format as "ufs", utilizing a
2971 separate process to avoid blocking the main Squid process on
2974 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
2976 see argument descriptions under ufs above
2978 Q1 specifies the number of unacknowledged I/O requests when Squid
2979 stops opening new files. If this many messages are in the queues,
2980 Squid won't open new files. Default is 64
2982 Q2 specifies the number of unacknowledged messages when Squid
2983 starts blocking. If this many messages are in the queues,
2984 Squid blocks until it receives some replies. Default is 72
2986 When Q1 < Q2 (the default), the cache directory is optimized
2987 for lower response time at the expense of a decrease in hit
2988 ratio. If Q1 > Q2, the cache directory is optimized for
2989 higher hit ratio at the expense of an increase in response
2992 The rock store type:
2994 cache_dir rock Directory-Name Mbytes <max-size=bytes> [options]
2996 The Rock Store type is a database-style storage. All cached
2997 entries are stored in a "database" file, using fixed-size slots,
2998 one entry per slot. The database size is specified in MB. The
2999 slot size is specified in bytes using the max-size option. See
3000 below for more info on the max-size option.
3002 swap-timeout=msec: Squid will not start writing a miss to or
3003 reading a hit from disk if it estimates that the swap operation
3004 will take more than the specified number of milliseconds. By
3005 default and when set to zero, disables the disk I/O time limit
3006 enforcement. Ignored when using blocking I/O module because
3007 blocking synchronous I/O does not allow Squid to estimate the
3008 expected swap wait time.
3010 max-swap-rate=swaps/sec: Artificially limits disk access using
3011 the specified I/O rate limit. Swap out requests that
3012 would cause the average I/O rate to exceed the limit are
3013 delayed. Individual swap in requests (i.e., hits or reads) are
3014 not delayed, but they do contribute to measured swap rate and
3015 since they are placed in the same FIFO queue as swap out
3016 requests, they may wait longer if max-swap-rate is smaller.
3017 This is necessary on file systems that buffer "too
3018 many" writes and then start blocking Squid and other processes
3019 while committing those writes to disk. Usually used together
3020 with swap-timeout to avoid excessive delays and queue overflows
3021 when disk demand exceeds available disk "bandwidth". By default
3022 and when set to zero, disables the disk I/O rate limit
3023 enforcement. Currently supported by IpcIo module only.
3026 The coss store type:
3028 NP: COSS filesystem in Squid-3 has been deemed too unstable for
3029 production use and has thus been removed from this release.
3030 We hope that it can be made usable again soon.
3032 block-size=n defines the "block size" for COSS cache_dir's.
3033 Squid uses file numbers as block numbers. Since file numbers
3034 are limited to 24 bits, the block size determines the maximum
3035 size of the COSS partition. The default is 512 bytes, which
3036 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
3037 you should not change the coss block size after Squid
3038 has written some objects to the cache_dir.
3040 The coss file store has changed from 2.5. Now it uses a file
3041 called 'stripe' in the directory names in the config - and
3042 this will be created by squid -z.
3046 no-store, no new objects should be stored to this cache_dir
3048 min-size=n, refers to the min object size in bytes this cache_dir
3049 will accept. It's used to restrict a cache_dir to only store
3050 large objects (e.g. aufs) while other storedirs are optimized
3051 for smaller objects (e.g. COSS). Defaults to 0.
3053 max-size=n, refers to the max object size in bytes this cache_dir
3054 supports. It is used to select the cache_dir to store the object.
3055 Note: To make optimal use of the max-size limits you should order
3056 the cache_dir lines with the smallest max-size value first and the
3057 ones with no max-size specification last.
3059 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
3060 which can be changed with the --with-coss-membuf-size=N configure
3064 # Uncomment and adjust the following to add a disk cache directory.
3065 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3069 NAME: store_dir_select_algorithm
3071 LOC: Config.store_dir_select_algorithm
3074 Set this to 'round-robin' as an alternative.
3077 NAME: max_open_disk_fds
3079 LOC: Config.max_open_disk_fds
3082 To avoid having disk as the I/O bottleneck Squid can optionally
3083 bypass the on-disk cache if more than this amount of disk file
3084 descriptors are open.
3086 A value of 0 indicates no limit.
3089 NAME: minimum_object_size
3093 LOC: Config.Store.minObjectSize
3095 Objects smaller than this size will NOT be saved on disk. The
3096 value is specified in kilobytes, and the default is 0 KB, which
3097 means there is no minimum.
3100 NAME: maximum_object_size
3104 LOC: Config.Store.maxObjectSize
3106 Objects larger than this size will NOT be saved on disk. The
3107 value is specified in kilobytes, and the default is 4MB. If
3108 you wish to get a high BYTES hit ratio, you should probably
3109 increase this (one 32 MB object hit counts for 3200 10KB
3110 hits). If you wish to increase speed more than your want to
3111 save bandwidth you should leave this low.
3113 NOTE: if using the LFUDA replacement policy you should increase
3114 this value to maximize the byte hit rate improvement of LFUDA!
3115 See replacement_policy below for a discussion of this policy.
3118 NAME: cache_swap_low
3119 COMMENT: (percent, 0-100)
3122 LOC: Config.Swap.lowWaterMark
3125 NAME: cache_swap_high
3126 COMMENT: (percent, 0-100)
3129 LOC: Config.Swap.highWaterMark
3132 The low- and high-water marks for cache object replacement.
3133 Replacement begins when the swap (disk) usage is above the
3134 low-water mark and attempts to maintain utilization near the
3135 low-water mark. As swap utilization gets close to high-water
3136 mark object eviction becomes more aggressive. If utilization is
3137 close to the low-water mark less replacement is done each time.
3139 Defaults are 90% and 95%. If you have a large cache, 5% could be
3140 hundreds of MB. If this is the case you may wish to set these
3141 numbers closer together.
3146 -----------------------------------------------------------------------------
3156 logformat <name> <format specification>
3158 Defines an access log format.
3160 The <format specification> is a string with embedded % format codes
3162 % format codes all follow the same basic structure where all but
3163 the formatcode is optional. Output strings are automatically escaped
3164 as required according to their context and the output format
3165 modifiers are usually not needed, but can be specified if an explicit
3166 output format is desired.
3168 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3170 " output in quoted string format
3171 [ output in squid text log format as used by log_mime_hdrs
3172 # output in URL quoted format
3177 width minimum and/or maximum field width:
3178 [width_min][.width_max]
3179 When minimum starts with 0, the field is zero-padded.
3180 String values exceeding maximum width are truncated.
3182 {arg} argument such as header name etc
3186 % a literal % character
3187 sn Unique sequence number per log line entry
3188 err_code The ID of an error response served by Squid or
3189 a similar internal error identifier.
3190 err_detail Additional err_code-dependent error information.
3192 Connection related format codes:
3194 >a Client source IP address
3196 >p Client source port
3197 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3198 >la Local IP address the client connected to
3199 >lp Local port number the client connected to
3201 la Local listening IP address the client connection was connected to.
3202 lp Local listening port number the client connection was connected to.
3204 <a Server IP address of the last server or peer connection
3205 <A Server FQDN or peer name
3206 <p Server port number of the last server or peer connection
3207 <la Local IP address of the last server or peer connection
3208 <lp Local port number of the last server or peer connection
3210 Time related format codes:
3212 ts Seconds since epoch
3213 tu subsecond time (milliseconds)
3214 tl Local time. Optional strftime format argument
3215 default %d/%b/%Y:%H:%M:%S %z
3216 tg GMT time. Optional strftime format argument
3217 default %d/%b/%Y:%H:%M:%S %z
3218 tr Response time (milliseconds)
3219 dt Total time spent making DNS lookups (milliseconds)
3221 Access Control related format codes:
3223 et Tag returned by external acl
3224 ea Log string returned by external acl
3225 un User name (any available)
3226 ul User name from authentication
3227 ue User name from external acl helper
3228 ui User name from ident
3229 us User name from SSL
3231 HTTP related format codes:
3233 [http::]>h Original request header. Optional header name argument
3234 on the format header[:[separator]element]
3235 [http::]>ha The HTTP request headers after adaptation and redirection.
3236 Optional header name argument as for >h
3237 [http::]<h Reply header. Optional header name argument
3239 [http::]>Hs HTTP status code sent to the client
3240 [http::]<Hs HTTP status code received from the next hop
3241 [http::]<bs Number of HTTP-equivalent message body bytes
3242 received from the next hop, excluding chunked
3243 transfer encoding and control messages.
3244 Generated FTP/Gopher listings are treated as
3246 [http::]mt MIME content type
3247 [http::]rm Request method (GET/POST etc)
3248 [http::]>rm Request method from client
3249 [http::]<rm Request method sent to server or peer
3250 [http::]ru Request URL from client (historic, filtered for logging)
3251 [http::]>ru Request URL from client
3252 [http::]<ru Request URL sent to server or peer
3253 [http::]rp Request URL-Path excluding hostname
3254 [http::]>rp Request URL-Path excluding hostname from client
3255 [http::]<rp Request URL-Path excluding hostname sento to server or peer
3256 [http::]rv Request protocol version
3257 [http::]>rv Request protocol version from client
3258 [http::]<rv Request protocol version sent to server or peer
3259 [http::]<st Sent reply size including HTTP headers
3260 [http::]>st Received request size including HTTP headers. In the
3261 case of chunked requests the chunked encoding metadata
3263 [http::]>sh Received HTTP request headers size
3264 [http::]<sh Sent HTTP reply headers size
3265 [http::]st Request+Reply size including HTTP headers
3266 [http::]<sH Reply high offset sent
3267 [http::]<sS Upstream object size
3268 [http::]<pt Peer response time in milliseconds. The timer starts
3269 when the last request byte is sent to the next hop
3270 and stops when the last response byte is received.
3271 [http::]<tt Total server-side time in milliseconds. The timer
3272 starts with the first connect request (or write I/O)
3273 sent to the first selected peer. The timer stops
3274 with the last I/O with the last peer.
3276 Squid handling related format codes:
3278 Ss Squid request status (TCP_MISS etc)
3279 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3281 If ICAP is enabled, the following code becomes available (as
3282 well as ICAP log codes documented with the icap_log option):
3284 icap::tt Total ICAP processing time for the HTTP
3285 transaction. The timer ticks when ICAP
3286 ACLs are checked and when ICAP
3287 transaction is in progress.
3289 If adaptation is enabled the following three codes become available:
3291 adapt::<last_h The header of the last ICAP response or
3292 meta-information from the last eCAP
3293 transaction related to the HTTP transaction.
3294 Like <h, accepts an optional header name
3297 adapt::sum_trs Summed adaptation transaction response
3298 times recorded as a comma-separated list in
3299 the order of transaction start time. Each time
3300 value is recorded as an integer number,
3301 representing response time of one or more
3302 adaptation (ICAP or eCAP) transaction in
3303 milliseconds. When a failed transaction is
3304 being retried or repeated, its time is not
3305 logged individually but added to the
3306 replacement (next) transaction. See also:
3309 adapt::all_trs All adaptation transaction response times.
3310 Same as adaptation_strs but response times of
3311 individual transactions are never added
3312 together. Instead, all transaction response
3313 times are recorded individually.
3315 You can prefix adapt::*_trs format codes with adaptation
3316 service name in curly braces to record response time(s) specific
3317 to that service. For example: %{my_service}adapt::sum_trs
3319 The default formats available (which do not need re-defining) are:
3321 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3322 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3323 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3324 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3325 logformat useragent %>a [%tl] "%{User-Agent}>h"
3327 NOTE: When the log_mime_hdrs directive is set to ON.
3328 The squid, common and combined formats have a safely encoded copy
3329 of the mime headers appended to each line within a pair of brackets.
3331 NOTE: The common and combined formats are not quite true to the Apache definition.
3332 The logs from Squid contain an extra status and hierarchy code appended.
3336 NAME: access_log cache_access_log
3338 LOC: Config.Log.accesslogs
3339 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3341 These files log client request activities. Has a line every HTTP or
3342 ICP request. The format is:
3343 access_log <module>:<place> [<logformat name> [acl acl ...]]
3344 access_log none [acl acl ...]]
3346 Will log to the specified module:place using the specified format (which
3347 must be defined in a logformat directive) those entries which match
3348 ALL the acl's specified (which must be defined in acl clauses).
3349 If no acl is specified, all requests will be logged to this destination.
3351 ===== Modules Currently available =====
3353 none Do not log any requests matching these ACL.
3354 Do not specify Place or logformat name.
3356 stdio Write each log line to disk immediately at the completion of
3358 Place: the filename and path to be written.
3360 daemon Very similar to stdio. But instead of writing to disk the log
3361 line is passed to a daemon helper for asychronous handling instead.
3362 Place: varies depending on the daemon.
3364 log_file_daemon Place: the file name and path to be written.
3366 syslog To log each request via syslog facility.
3367 Place: The syslog facility and priority level for these entries.
3368 Place Format: facility.priority
3370 where facility could be any of:
3371 authpriv, daemon, local0 ... local7 or user.
3373 And priority could be any of:
3374 err, warning, notice, info, debug.
3376 udp To send each log line as text data to a UDP receiver.
3377 Place: The destination host name or IP and port.
3378 Place Format: //host:port
3380 tcp To send each log line as text data to a TCP receiver.
3381 Place: The destination host name or IP and port.
3382 Place Format: //host:port
3385 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3391 LOC: Config.Log.icaplogs
3394 ICAP log files record ICAP transaction summaries, one line per
3397 The icap_log option format is:
3398 icap_log <filepath> [<logformat name> [acl acl ...]]
3399 icap_log none [acl acl ...]]
3401 Please see access_log option documentation for details. The two
3402 kinds of logs share the overall configuration approach and many
3405 ICAP processing of a single HTTP message or transaction may
3406 require multiple ICAP transactions. In such cases, multiple
3407 ICAP transaction log lines will correspond to a single access
3410 ICAP log uses logformat codes that make sense for an ICAP
3411 transaction. Header-related codes are applied to the HTTP header
3412 embedded in an ICAP server response, with the following caveats:
3413 For REQMOD, there is no HTTP response header unless the ICAP
3414 server performed request satisfaction. For RESPMOD, the HTTP
3415 request header is the header sent to the ICAP server. For
3416 OPTIONS, there are no HTTP headers.
3418 The following format codes are also available for ICAP logs:
3420 icap::<A ICAP server IP address. Similar to <A.
3422 icap::<service_name ICAP service name from the icap_service
3423 option in Squid configuration file.
3425 icap::ru ICAP Request-URI. Similar to ru.
3427 icap::rm ICAP request method (REQMOD, RESPMOD, or
3428 OPTIONS). Similar to existing rm.
3430 icap::>st Bytes sent to the ICAP server (TCP payload
3431 only; i.e., what Squid writes to the socket).
3433 icap::<st Bytes received from the ICAP server (TCP
3434 payload only; i.e., what Squid reads from
3437 icap::<bs Number of message body bytes received from the
3438 ICAP server. ICAP message body, if any, usually
3439 includes encapsulated HTTP message headers and
3440 possibly encapsulated HTTP message body. The
3441 HTTP body part is dechunked before its size is
3444 icap::tr Transaction response time (in
3445 milliseconds). The timer starts when
3446 the ICAP transaction is created and
3447 stops when the transaction is completed.
3450 icap::tio Transaction I/O time (in milliseconds). The
3451 timer starts when the first ICAP request
3452 byte is scheduled for sending. The timers
3453 stops when the last byte of the ICAP response
3456 icap::to Transaction outcome: ICAP_ERR* for all
3457 transaction errors, ICAP_OPT for OPTION
3458 transactions, ICAP_ECHO for 204
3459 responses, ICAP_MOD for message
3460 modification, and ICAP_SAT for request
3461 satisfaction. Similar to Ss.
3463 icap::Hs ICAP response status code. Similar to Hs.
3465 icap::>h ICAP request header(s). Similar to >h.
3467 icap::<h ICAP response header(s). Similar to <h.
3469 The default ICAP log format, which can be used without an explicit
3470 definition, is called icap_squid:
3472 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3474 See also: logformat, log_icap, and %adapt::<last_h
3477 NAME: logfile_daemon
3479 DEFAULT: @DEFAULT_LOGFILED@
3480 LOC: Log::TheConfig.logfile_daemon
3482 Specify the path to the logfile-writing daemon. This daemon is
3483 used to write the access and store logs, if configured.
3485 Squid sends a number of commands to the log daemon:
3486 L<data>\n - logfile data
3491 r<n>\n - set rotate count to <n>
3492 b<n>\n - 1 = buffer output, 0 = don't buffer output
3494 No responses is expected.
3499 LOC: Config.accessList.log
3501 COMMENT: allow|deny acl acl...
3503 This options allows you to control which requests gets logged
3504 to access.log (see access_log directive). Requests denied for
3505 logging will also not be accounted for in performance counters.
3507 This clause only supports fast acl types.
3508 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3514 LOC: Config.accessList.icap
3517 This options allows you to control which requests get logged
3518 to icap.log. See the icap_log directive for ICAP log details.
3521 NAME: cache_store_log
3524 LOC: Config.Log.store
3526 Logs the activities of the storage manager. Shows which
3527 objects are ejected from the cache, and which objects are
3528 saved and for how long. To disable, enter "none" or remove the line.
3529 There are not really utilities to analyze this data, so you can safely
3533 cache_store_log @DEFAULT_STORE_LOG@
3536 NAME: cache_swap_state cache_swap_log
3538 LOC: Config.Log.swap
3541 Location for the cache "swap.state" file. This index file holds
3542 the metadata of objects saved on disk. It is used to rebuild
3543 the cache during startup. Normally this file resides in each
3544 'cache_dir' directory, but you may specify an alternate
3545 pathname here. Note you must give a full filename, not just
3546 a directory. Since this is the index for the whole object
3547 list you CANNOT periodically rotate it!
3549 If %s can be used in the file name it will be replaced with a
3550 a representation of the cache_dir name where each / is replaced
3551 with '.'. This is needed to allow adding/removing cache_dir
3552 lines when cache_swap_log is being used.
3554 If have more than one 'cache_dir', and %s is not used in the name
3555 these swap logs will have names such as:
3561 The numbered extension (which is added automatically)
3562 corresponds to the order of the 'cache_dir' lines in this
3563 configuration file. If you change the order of the 'cache_dir'
3564 lines in this file, these index files will NOT correspond to
3565 the correct 'cache_dir' entry (unless you manually rename
3566 them). We recommend you do NOT use this option. It is
3567 better to keep these index files in each 'cache_dir' directory.
3570 NAME: logfile_rotate
3573 LOC: Config.Log.rotateNumber
3575 Specifies the number of logfile rotations to make when you
3576 type 'squid -k rotate'. The default is 10, which will rotate
3577 with extensions 0 through 9. Setting logfile_rotate to 0 will
3578 disable the file name rotation, but the logfiles are still closed
3579 and re-opened. This will enable you to rename the logfiles
3580 yourself just before sending the rotate signal.
3582 Note, the 'squid -k rotate' command normally sends a USR1
3583 signal to the running squid process. In certain situations
3584 (e.g. on Linux with Async I/O), USR1 is used for other
3585 purposes, so -k rotate uses another signal. It is best to get
3586 in the habit of using 'squid -k rotate' instead of 'kill -USR1
3589 Note, from Squid-3.1 this option has no effect on the cache.log,
3590 that log can be rotated separately by using debug_options
3593 NAME: emulate_httpd_log
3596 Replace this with an access_log directive using the format 'common' or 'combined'.
3599 NAME: log_ip_on_direct
3602 Remove this option from your config. To log server or peer names use %<A in the log format.
3607 DEFAULT: @DEFAULT_MIME_TABLE@
3608 LOC: Config.mimeTablePathname
3610 Pathname to Squid's MIME table. You shouldn't need to change
3611 this, but the default file contains examples and formatting
3612 information if you do.
3618 LOC: Config.onoff.log_mime_hdrs
3621 The Cache can record both the request and the response MIME
3622 headers for each HTTP transaction. The headers are encoded
3623 safely and will appear as two bracketed fields at the end of
3624 the access log (for either the native or httpd-emulated log
3625 formats). To enable this logging set log_mime_hdrs to 'on'.
3631 Replace this with an access_log directive using the format 'useragent'.
3634 NAME: referer_log referrer_log
3637 Replace this with an access_log directive using the format 'referrer'.
3642 DEFAULT: @DEFAULT_PID_FILE@
3643 LOC: Config.pidFilename
3645 A filename to write the process-id to. To disable, enter "none".
3651 Remove this option from your config. To log FQDN use %>A in the log format.
3654 NAME: client_netmask
3656 LOC: Config.Addrs.client_netmask
3659 A netmask for client addresses in logfiles and cachemgr output.
3660 Change this to protect the privacy of your cache clients.
3661 A netmask of 255.255.255.0 will log all IP's in that range with
3662 the last digit set to '0'.
3668 Use a regular access.log with ACL limiting it to MISS events.
3671 NAME: strip_query_terms
3673 LOC: Config.onoff.strip_query_terms
3676 By default, Squid strips query terms from requested URLs before
3677 logging. This protects your user's privacy.
3684 LOC: Config.onoff.buffered_logs
3686 cache.log log file is written with stdio functions, and as such
3687 it can be buffered or unbuffered. By default it will be unbuffered.
3688 Buffering it can speed up the writing slightly (though you are
3689 unlikely to need to worry unless you run with tons of debugging
3690 enabled in which case performance will suffer badly anyway..).
3693 NAME: netdb_filename
3695 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
3696 LOC: Config.netdbFilename
3699 A filename where Squid stores it's netdb state between restarts.
3700 To disable, enter "none".
3704 OPTIONS FOR TROUBLESHOOTING
3705 -----------------------------------------------------------------------------
3710 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
3711 LOC: Debug::cache_log
3713 Cache logging file. This is where general information about
3714 your cache's behavior goes. You can increase the amount of data
3715 logged to this file and how often its rotated with "debug_options"
3721 LOC: Debug::debugOptions
3723 Logging options are set as section,level where each source file
3724 is assigned a unique section. Lower levels result in less
3725 output, Full debugging (level 9) can result in a very large
3726 log file, so be careful.
3728 The magic word "ALL" sets debugging levels for all sections.
3729 We recommend normally running with "ALL,1".
3731 The rotate=N option can be used to keep more or less of these logs
3732 than would otherwise be kept by logfile_rotate.
3733 For most uses a single log should be enough to monitor current
3734 events affecting Squid.
3739 LOC: Config.coredump_dir
3740 DEFAULT_IF_NONE: none
3742 By default Squid leaves core files in the directory from where
3743 it was started. If you set 'coredump_dir' to a directory
3744 that exists, Squid will chdir() to that directory at startup
3745 and coredump files will be left there.
3749 # Leave coredumps in the first cache dir
3750 coredump_dir @DEFAULT_SWAP_DIR@
3756 OPTIONS FOR FTP GATEWAYING
3757 -----------------------------------------------------------------------------
3763 LOC: Config.Ftp.anon_user
3765 If you want the anonymous login password to be more informative
3766 (and enable the use of picky ftp servers), set this to something
3767 reasonable for your domain, like wwwuser@somewhere.net
3769 The reason why this is domainless by default is the
3770 request can be made on the behalf of a user in any domain,
3771 depending on how the cache is used.
3772 Some ftp server also validate the email address is valid
3773 (for example perl.com).
3779 LOC: Config.Ftp.passive
3781 If your firewall does not allow Squid to use passive
3782 connections, turn off this option.
3784 Use of ftp_epsv_all option requires this to be ON.
3790 LOC: Config.Ftp.epsv_all
3792 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
3794 NATs may be able to put the connection on a "fast path" through the
3795 translator, as the EPRT command will never be used and therefore,
3796 translation of the data portion of the segments will never be needed.
3798 When a client only expects to do two-way FTP transfers this may be
3800 If squid finds that it must do a three-way FTP transfer after issuing
3801 an EPSV ALL command, the FTP session will fail.
3803 If you have any doubts about this option do not use it.
3804 Squid will nicely attempt all other connection methods.
3806 Requires ftp_passive to be ON (default) for any effect.
3812 LOC: Config.Ftp.epsv
3814 FTP Protocol extensions permit the use of a special "EPSV" command.
3816 NATs may be able to put the connection on a "fast path" through the
3817 translator using EPSV, as the EPRT command will never be used
3818 and therefore, translation of the data portion of the segments
3819 will never be needed.
3821 Turning this OFF will prevent EPSV being attempted.
3822 WARNING: Doing so will convert Squid back to the old behavior with all
3823 the related problems with external NAT devices/layers.
3825 Requires ftp_passive to be ON (default) for any effect.
3831 LOC: Config.Ftp.eprt
3833 FTP Protocol extensions permit the use of a special "EPRT" command.
3835 This extension provides a protocol neutral alternative to the
3836 IPv4-only PORT command. When supported it enables active FTP data
3837 channels over IPv6 and efficient NAT handling.
3839 Turning this OFF will prevent EPRT being attempted and will skip
3840 straight to using PORT for IPv4 servers.
3842 Some devices are known to not handle this extension correctly and
3843 may result in crashes. Devices which suport EPRT enough to fail
3844 cleanly will result in Squid attempting PORT anyway. This directive
3845 should only be disabled when EPRT results in device failures.
3847 WARNING: Doing so will convert Squid back to the old behavior with all
3848 the related problems with external NAT devices/layers and IPv4-only FTP.
3851 NAME: ftp_sanitycheck
3854 LOC: Config.Ftp.sanitycheck
3856 For security and data integrity reasons Squid by default performs
3857 sanity checks of the addresses of FTP data connections ensure the
3858 data connection is to the requested server. If you need to allow
3859 FTP connections to servers using another IP address for the data
3860 connection turn this off.
3863 NAME: ftp_telnet_protocol
3866 LOC: Config.Ftp.telnet
3868 The FTP protocol is officially defined to use the telnet protocol
3869 as transport channel for the control connection. However, many
3870 implementations are broken and does not respect this aspect of
3873 If you have trouble accessing files with ASCII code 255 in the
3874 path or similar problems involving this ASCII code you can
3875 try setting this directive to off. If that helps, report to the
3876 operator of the FTP server in question that their FTP server
3877 is broken and does not follow the FTP standard.
3881 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
3882 -----------------------------------------------------------------------------
3887 DEFAULT: @DEFAULT_DISKD@
3888 LOC: Config.Program.diskd
3890 Specify the location of the diskd executable.
3891 Note this is only useful if you have compiled in
3892 diskd as one of the store io modules.
3895 NAME: unlinkd_program
3898 DEFAULT: @DEFAULT_UNLINKD@
3899 LOC: Config.Program.unlinkd
3901 Specify the location of the executable for file deletion process.
3904 NAME: pinger_program
3906 DEFAULT: @DEFAULT_PINGER@
3907 LOC: Config.pinger.program
3910 Specify the location of the executable for the pinger process.
3916 LOC: Config.pinger.enable
3919 Control whether the pinger is active at run-time.
3920 Enables turning ICMP pinger on and off with a simple
3921 squid -k reconfigure.
3926 OPTIONS FOR URL REWRITING
3927 -----------------------------------------------------------------------------
3930 NAME: url_rewrite_program redirect_program
3932 LOC: Config.Program.redirect
3935 Specify the location of the executable URL rewriter to use.
3936 Since they can perform almost any function there isn't one included.
3938 For each requested URL, the rewriter will receive on line with the format
3940 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
3942 In the future, the rewriter interface will be extended with
3943 key=value pairs ("kvpairs" shown above). Rewriter programs
3944 should be prepared to receive and possibly ignore additional
3945 whitespace-separated tokens on each input line.
3947 And the rewriter may return a rewritten URL. The other components of
3948 the request line does not need to be returned (ignored if they are).
3950 The rewriter can also indicate that a client-side redirect should
3951 be performed to the new URL. This is done by prefixing the returned
3952 URL with "301:" (moved permanently) or 302: (moved temporarily), etc.
3954 By default, a URL rewriter is not used.
3957 NAME: url_rewrite_children redirect_children
3958 TYPE: HelperChildConfig
3959 DEFAULT: 20 startup=0 idle=1 concurrency=0
3960 LOC: Config.redirectChildren
3962 The maximum number of redirector processes to spawn. If you limit
3963 it too few Squid will have to wait for them to process a backlog of
3964 URLs, slowing it down. If you allow too many they will use RAM
3965 and other system resources noticably.
3967 The startup= and idle= options allow some measure of skew in your
3972 Sets a minimum of how many processes are to be spawned when Squid
3973 starts or reconfigures. When set to zero the first request will
3974 cause spawning of the first child process to handle it.
3976 Starting too few will cause an initial slowdown in traffic as Squid
3977 attempts to simultaneously spawn enough processes to cope.
3981 Sets a minimum of how many processes Squid is to try and keep available
3982 at all times. When traffic begins to rise above what the existing
3983 processes can handle this many more will be spawned up to the maximum
3984 configured. A minimum setting of 1 is required.
3988 The number of requests each redirector helper can handle in
3989 parallel. Defaults to 0 which indicates the redirector
3990 is a old-style single threaded redirector.
3992 When this directive is set to a value >= 1 then the protocol
3993 used to communicate with the helper is modified to include
3994 a request ID in front of the request/response. The request
3995 ID from the request must be echoed back with the response
3999 NAME: url_rewrite_host_header redirect_rewrites_host_header
4002 LOC: Config.onoff.redir_rewrites_host
4004 To preserve same-origin security policies in browsers and
4005 prevent Host: header forgery by redirectors Squid rewrites
4006 any Host: header in redirected requests.
4008 If you are running an accelerator this may not be a wanted
4009 effect of a redirector. This directive enables you disable
4010 Host: alteration in reverse-proxy traffic.
4012 WARNING: Entries are cached on the result of the URL rewriting
4013 process, so be careful if you have domain-virtual hosts.
4015 WARNING: Squid and other software verifies the URL and Host
4016 are matching, so be careful not to relay through other proxies
4017 or inspecting firewalls with this disabled.
4020 NAME: url_rewrite_access redirector_access
4023 LOC: Config.accessList.redirector
4025 If defined, this access list specifies which requests are
4026 sent to the redirector processes. By default all requests
4029 This clause supports both fast and slow acl types.
4030 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4033 NAME: url_rewrite_bypass redirector_bypass
4035 LOC: Config.onoff.redirector_bypass
4038 When this is 'on', a request will not go through the
4039 redirector if all redirectors are busy. If this is 'off'
4040 and the redirector queue grows too large, Squid will exit
4041 with a FATAL error and ask you to increase the number of
4042 redirectors. You should only enable this if the redirectors
4043 are not critical to your caching system. If you use
4044 redirectors for access control, and you enable this option,
4045 users may have access to pages they should not
4046 be allowed to request.
4050 OPTIONS FOR TUNING THE CACHE
4051 -----------------------------------------------------------------------------
4054 NAME: cache no_cache
4057 LOC: Config.accessList.noCache
4059 A list of ACL elements which, if matched and denied, cause the request to
4060 not be satisfied from the cache and the reply to not be cached.
4061 In other words, use this to force certain objects to never be cached.
4063 You must use the words 'allow' or 'deny' to indicate whether items
4064 matching the ACL should be allowed or denied into the cache.
4066 Default is to allow all to be cached.
4068 This clause supports both fast and slow acl types.
4069 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4075 LOC: Config.maxStale
4078 This option puts an upper limit on how stale content Squid
4079 will serve from the cache if cache validation fails.
4080 Can be overriden by the refresh_pattern max-stale option.
4083 NAME: refresh_pattern
4084 TYPE: refreshpattern
4088 usage: refresh_pattern [-i] regex min percent max [options]
4090 By default, regular expressions are CASE-SENSITIVE. To make
4091 them case-insensitive, use the -i option.
4093 'Min' is the time (in minutes) an object without an explicit
4094 expiry time should be considered fresh. The recommended
4095 value is 0, any higher values may cause dynamic applications
4096 to be erroneously cached unless the application designer
4097 has taken the appropriate actions.
4099 'Percent' is a percentage of the objects age (time since last
4100 modification age) an object without explicit expiry time
4101 will be considered fresh.
4103 'Max' is an upper limit on how long objects without an explicit
4104 expiry time will be considered fresh.
4106 options: override-expire
4112 ignore-must-revalidate
4119 override-expire enforces min age even if the server
4120 sent an explicit expiry time (e.g., with the
4121 Expires: header or Cache-Control: max-age). Doing this
4122 VIOLATES the HTTP standard. Enabling this feature
4123 could make you liable for problems which it causes.
4125 Note: override-expire does not enforce staleness - it only extends
4126 freshness / min. If the server returns a Expires time which
4127 is longer than your max time, Squid will still consider
4128 the object fresh for that period of time.
4130 override-lastmod enforces min age even on objects
4131 that were modified recently.
4133 reload-into-ims changes client no-cache or ``reload''
4134 to If-Modified-Since requests. Doing this VIOLATES the
4135 HTTP standard. Enabling this feature could make you
4136 liable for problems which it causes.
4138 ignore-reload ignores a client no-cache or ``reload''
4139 header. Doing this VIOLATES the HTTP standard. Enabling
4140 this feature could make you liable for problems which
4143 ignore-no-cache ignores any ``Pragma: no-cache'' and
4144 ``Cache-control: no-cache'' headers received from a server.
4145 The HTTP RFC never allows the use of this (Pragma) header
4146 from a server, only a client, though plenty of servers
4149 ignore-no-store ignores any ``Cache-control: no-store''
4150 headers received from a server. Doing this VIOLATES
4151 the HTTP standard. Enabling this feature could make you
4152 liable for problems which it causes.
4154 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
4155 headers received from a server. Doing this VIOLATES
4156 the HTTP standard. Enabling this feature could make you
4157 liable for problems which it causes.
4159 ignore-private ignores any ``Cache-control: private''
4160 headers received from a server. Doing this VIOLATES
4161 the HTTP standard. Enabling this feature could make you
4162 liable for problems which it causes.
4164 ignore-auth caches responses to requests with authorization,
4165 as if the originserver had sent ``Cache-control: public''
4166 in the response header. Doing this VIOLATES the HTTP standard.
4167 Enabling this feature could make you liable for problems which
4170 refresh-ims causes squid to contact the origin server
4171 when a client issues an If-Modified-Since request. This
4172 ensures that the client will receive an updated version
4173 if one is available.
4175 store-stale stores responses even if they don't have explicit
4176 freshness or a validator (i.e., Last-Modified or an ETag)
4177 present, or if they're already stale. By default, Squid will
4178 not cache such responses because they usually can't be
4179 reused. Note that such responses will be stale by default.
4181 max-stale=NN provide a maximum staleness factor. Squid won't
4182 serve objects more stale than this even if it failed to
4183 validate the object. Default: use the max_stale global limit.
4185 Basically a cached object is:
4187 FRESH if expires < now, else STALE
4189 FRESH if lm-factor < percent, else STALE
4193 The refresh_pattern lines are checked in the order listed here.
4194 The first entry which matches is used. If none of the entries
4195 match the default will be used.
4197 Note, you must uncomment all the default lines if you want
4198 to change one. The default setting is only active if none is
4203 # Add any of your own refresh_pattern entries above these.
4204 refresh_pattern ^ftp: 1440 20% 10080
4205 refresh_pattern ^gopher: 1440 0% 1440
4206 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
4207 refresh_pattern . 0 20% 4320
4211 NAME: quick_abort_min
4215 LOC: Config.quickAbort.min
4218 NAME: quick_abort_max
4222 LOC: Config.quickAbort.max
4225 NAME: quick_abort_pct
4229 LOC: Config.quickAbort.pct
4231 The cache by default continues downloading aborted requests
4232 which are almost completed (less than 16 KB remaining). This
4233 may be undesirable on slow (e.g. SLIP) links and/or very busy
4234 caches. Impatient users may tie up file descriptors and
4235 bandwidth by repeatedly requesting and immediately aborting
4238 When the user aborts a request, Squid will check the
4239 quick_abort values to the amount of data transfered until
4242 If the transfer has less than 'quick_abort_min' KB remaining,
4243 it will finish the retrieval.
4245 If the transfer has more than 'quick_abort_max' KB remaining,
4246 it will abort the retrieval.
4248 If more than 'quick_abort_pct' of the transfer has completed,
4249 it will finish the retrieval.
4251 If you do not want any retrieval to continue after the client
4252 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
4255 If you want retrievals to always continue if they are being
4256 cached set 'quick_abort_min' to '-1 KB'.
4259 NAME: read_ahead_gap
4260 COMMENT: buffer-size
4262 LOC: Config.readAheadGap
4265 The amount of data the cache will buffer ahead of what has been
4266 sent to the client when retrieving an object from another server.
4270 IFDEF: USE_HTTP_VIOLATIONS
4273 LOC: Config.negativeTtl
4276 Set the Default Time-to-Live (TTL) for failed requests.
4277 Certain types of failures (such as "connection refused" and
4278 "404 Not Found") are able to be negatively-cached for a short time.
4279 Modern web servers should provide Expires: header, however if they
4280 do not this can provide a minimum TTL.
4281 The default is not to cache errors with unknown expiry details.
4283 Note that this is different from negative caching of DNS lookups.
4285 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4286 this feature could make you liable for problems which it
4290 NAME: positive_dns_ttl
4293 LOC: Config.positiveDnsTtl
4296 Upper limit on how long Squid will cache positive DNS responses.
4297 Default is 6 hours (360 minutes). This directive must be set
4298 larger than negative_dns_ttl.
4301 NAME: negative_dns_ttl
4304 LOC: Config.negativeDnsTtl
4307 Time-to-Live (TTL) for negative caching of failed DNS lookups.
4308 This also sets the lower cache limit on positive lookups.
4309 Minimum value is 1 second, and it is not recommendable to go
4310 much below 10 seconds.
4313 NAME: range_offset_limit
4314 COMMENT: size [acl acl...]
4316 LOC: Config.rangeOffsetLimit
4319 usage: (size) [units] [[!]aclname]
4321 Sets an upper limit on how far (number of bytes) into the file
4322 a Range request may be to cause Squid to prefetch the whole file.
4323 If beyond this limit, Squid forwards the Range request as it is and
4324 the result is NOT cached.
4326 This is to stop a far ahead range request (lets say start at 17MB)
4327 from making Squid fetch the whole object up to that point before
4328 sending anything to the client.
4330 Multiple range_offset_limit lines may be specified, and they will
4331 be searched from top to bottom on each request until a match is found.
4332 The first match found will be used. If no line matches a request, the
4333 default limit of 0 bytes will be used.
4335 'size' is the limit specified as a number of units.
4337 'units' specifies whether to use bytes, KB, MB, etc.
4338 If no units are specified bytes are assumed.
4340 A size of 0 causes Squid to never fetch more than the
4341 client requested. (default)
4343 A size of 'none' causes Squid to always fetch the object from the
4344 beginning so it may cache the result. (2.0 style)
4346 'aclname' is the name of a defined ACL.
4348 NP: Using 'none' as the byte value here will override any quick_abort settings
4349 that may otherwise apply to the range request. The range request will
4350 be fully fetched from start to finish regardless of the client
4351 actions. This affects bandwidth usage.
4354 NAME: minimum_expiry_time
4357 LOC: Config.minimum_expiry_time
4360 The minimum caching time according to (Expires - Date)
4361 Headers Squid honors if the object can't be revalidated
4362 defaults to 60 seconds. In reverse proxy environments it
4363 might be desirable to honor shorter object lifetimes. It
4364 is most likely better to make your server return a
4365 meaningful Last-Modified header however. In ESI environments
4366 where page fragments often have short lifetimes, this will
4367 often be best set to 0.
4370 NAME: store_avg_object_size
4374 LOC: Config.Store.avgObjectSize
4376 Average object size, used to estimate number of objects your
4377 cache can hold. The default is 13 KB.
4380 NAME: store_objects_per_bucket
4383 LOC: Config.Store.objectsPerBucket
4385 Target number of objects per bucket in the store hash table.
4386 Lowering this value increases the total number of buckets and
4387 also the storage maintenance rate. The default is 20.
4392 -----------------------------------------------------------------------------
4395 NAME: request_header_max_size
4399 LOC: Config.maxRequestHeaderSize
4401 This specifies the maximum size for HTTP headers in a request.
4402 Request headers are usually relatively small (about 512 bytes).
4403 Placing a limit on the request header size will catch certain
4404 bugs (for example with persistent connections) and possibly
4405 buffer-overflow or denial-of-service attacks.
4408 NAME: reply_header_max_size
4412 LOC: Config.maxReplyHeaderSize
4414 This specifies the maximum size for HTTP headers in a reply.
4415 Reply headers are usually relatively small (about 512 bytes).
4416 Placing a limit on the reply header size will catch certain
4417 bugs (for example with persistent connections) and possibly
4418 buffer-overflow or denial-of-service attacks.
4421 NAME: request_body_max_size
4425 LOC: Config.maxRequestBodySize
4427 This specifies the maximum size for an HTTP request body.
4428 In other words, the maximum size of a PUT/POST request.
4429 A user who attempts to send a request with a body larger
4430 than this limit receives an "Invalid Request" error message.
4431 If you set this parameter to a zero (the default), there will
4432 be no limit imposed.
4435 NAME: client_request_buffer_max_size
4439 LOC: Config.maxRequestBufferSize
4441 This specifies the maximum buffer size of a client request.
4442 It prevents squid eating too much memory when somebody uploads
4446 NAME: chunked_request_body_max_size
4450 LOC: Config.maxChunkedRequestBodySize
4452 A broken or confused HTTP/1.1 client may send a chunked HTTP
4453 request to Squid. Squid does not have full support for that
4454 feature yet. To cope with such requests, Squid buffers the
4455 entire request and then dechunks request body to create a
4456 plain HTTP/1.0 request with a known content length. The plain
4457 request is then used by the rest of Squid code as usual.
4459 The option value specifies the maximum size of the buffer used
4460 to hold the request before the conversion. If the chunked
4461 request size exceeds the specified limit, the conversion
4462 fails, and the client receives an "unsupported request" error,
4463 as if dechunking was disabled.
4465 Dechunking is enabled by default. To disable conversion of
4466 chunked requests, set the maximum to zero.
4468 Request dechunking feature and this option in particular are a
4469 temporary hack. When chunking requests and responses are fully
4470 supported, there will be no need to buffer a chunked request.
4474 IFDEF: USE_HTTP_VIOLATIONS
4477 LOC: Config.accessList.brokenPosts
4479 A list of ACL elements which, if matched, causes Squid to send
4480 an extra CRLF pair after the body of a PUT/POST request.
4482 Some HTTP servers has broken implementations of PUT/POST,
4483 and rely on an extra CRLF pair sent by some WWW clients.
4485 Quote from RFC2616 section 4.1 on this matter:
4487 Note: certain buggy HTTP/1.0 client implementations generate an
4488 extra CRLF's after a POST request. To restate what is explicitly
4489 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
4490 a request with an extra CRLF.
4492 This clause only supports fast acl types.
4493 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4496 acl buggy_server url_regex ^http://....
4497 broken_posts allow buggy_server
4500 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
4503 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
4505 LOC: Adaptation::Config::use_indirect_client
4507 Controls whether the indirect client IP address (instead of the direct
4508 client IP address) is passed to adaptation services.
4510 See also: follow_x_forwarded_for adaptation_send_client_ip
4514 IFDEF: USE_HTTP_VIOLATIONS
4518 LOC: Config.onoff.via
4520 If set (default), Squid will include a Via header in requests and
4521 replies as required by RFC2616.
4527 LOC: Config.onoff.ie_refresh
4530 Microsoft Internet Explorer up until version 5.5 Service
4531 Pack 1 has an issue with transparent proxies, wherein it
4532 is impossible to force a refresh. Turning this on provides
4533 a partial fix to the problem, by causing all IMS-REFRESH
4534 requests from older IE versions to check the origin server
4535 for fresh content. This reduces hit ratio by some amount
4536 (~10% in my experience), but allows users to actually get
4537 fresh content when they want it. Note because Squid
4538 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
4539 of 5.5 is unchanged from old versions of Squid (i.e. a
4540 forced refresh is impossible). Newer versions of IE will,
4541 hopefully, continue to have the new behavior and will be
4542 handled based on that assumption. This option defaults to
4543 the old Squid behavior, which is better for hit ratios but
4544 worse for clients using IE, if they need to be able to
4545 force fresh content.
4548 NAME: vary_ignore_expire
4551 LOC: Config.onoff.vary_ignore_expire
4554 Many HTTP servers supporting Vary gives such objects
4555 immediate expiry time with no cache-control header
4556 when requested by a HTTP/1.0 client. This option
4557 enables Squid to ignore such expiry times until
4558 HTTP/1.1 is fully implemented.
4560 WARNING: If turned on this may eventually cause some
4561 varying objects not intended for caching to get cached.
4564 NAME: request_entities
4566 LOC: Config.onoff.request_entities
4569 Squid defaults to deny GET and HEAD requests with request entities,
4570 as the meaning of such requests are undefined in the HTTP standard
4571 even if not explicitly forbidden.
4573 Set this directive to on if you have clients which insists
4574 on sending request entities in GET or HEAD requests. But be warned
4575 that there is server software (both proxies and web servers) which
4576 can fail to properly process this kind of request which may make you
4577 vulnerable to cache pollution attacks if enabled.
4580 NAME: request_header_access
4581 IFDEF: USE_HTTP_VIOLATIONS
4582 TYPE: http_header_access[]
4583 LOC: Config.request_header_access
4586 Usage: request_header_access header_name allow|deny [!]aclname ...
4588 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4589 this feature could make you liable for problems which it
4592 This option replaces the old 'anonymize_headers' and the
4593 older 'http_anonymizer' option with something that is much
4594 more configurable. This new method creates a list of ACLs
4595 for each header, allowing you very fine-tuned header
4598 This option only applies to request headers, i.e., from the
4599 client to the server.
4601 You can only specify known headers for the header name.
4602 Other headers are reclassified as 'Other'. You can also
4603 refer to all the headers with 'All'.
4605 For example, to achieve the same behavior as the old
4606 'http_anonymizer standard' option, you should use:
4608 request_header_access From deny all
4609 request_header_access Referer deny all
4610 request_header_access Server deny all
4611 request_header_access User-Agent deny all
4612 request_header_access WWW-Authenticate deny all
4613 request_header_access Link deny all
4615 Or, to reproduce the old 'http_anonymizer paranoid' feature
4618 request_header_access Allow allow all
4619 request_header_access Authorization allow all
4620 request_header_access WWW-Authenticate allow all
4621 request_header_access Proxy-Authorization allow all
4622 request_header_access Proxy-Authenticate allow all
4623 request_header_access Cache-Control allow all
4624 request_header_access Content-Encoding allow all
4625 request_header_access Content-Length allow all
4626 request_header_access Content-Type allow all
4627 request_header_access Date allow all
4628 request_header_access Expires allow all
4629 request_header_access Host allow all
4630 request_header_access If-Modified-Since allow all
4631 request_header_access Last-Modified allow all
4632 request_header_access Location allow all
4633 request_header_access Pragma allow all
4634 request_header_access Accept allow all
4635 request_header_access Accept-Charset allow all
4636 request_header_access Accept-Encoding allow all
4637 request_header_access Accept-Language allow all
4638 request_header_access Content-Language allow all
4639 request_header_access Mime-Version allow all
4640 request_header_access Retry-After allow all
4641 request_header_access Title allow all
4642 request_header_access Connection allow all
4643 request_header_access All deny all
4645 although many of those are HTTP reply headers, and so should be
4646 controlled with the reply_header_access directive.
4648 By default, all headers are allowed (no anonymizing is
4652 NAME: reply_header_access
4653 IFDEF: USE_HTTP_VIOLATIONS
4654 TYPE: http_header_access[]
4655 LOC: Config.reply_header_access
4658 Usage: reply_header_access header_name allow|deny [!]aclname ...
4660 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4661 this feature could make you liable for problems which it
4664 This option only applies to reply headers, i.e., from the
4665 server to the client.
4667 This is the same as request_header_access, but in the other
4670 This option replaces the old 'anonymize_headers' and the
4671 older 'http_anonymizer' option with something that is much
4672 more configurable. This new method creates a list of ACLs
4673 for each header, allowing you very fine-tuned header
4676 You can only specify known headers for the header name.
4677 Other headers are reclassified as 'Other'. You can also
4678 refer to all the headers with 'All'.
4680 For example, to achieve the same behavior as the old
4681 'http_anonymizer standard' option, you should use:
4683 reply_header_access From deny all
4684 reply_header_access Referer deny all
4685 reply_header_access Server deny all
4686 reply_header_access User-Agent deny all
4687 reply_header_access WWW-Authenticate deny all
4688 reply_header_access Link deny all
4690 Or, to reproduce the old 'http_anonymizer paranoid' feature
4693 reply_header_access Allow allow all
4694 reply_header_access Authorization allow all
4695 reply_header_access WWW-Authenticate allow all
4696 reply_header_access Proxy-Authorization allow all
4697 reply_header_access Proxy-Authenticate allow all
4698 reply_header_access Cache-Control allow all
4699 reply_header_access Content-Encoding allow all
4700 reply_header_access Content-Length allow all
4701 reply_header_access Content-Type allow all
4702 reply_header_access Date allow all
4703 reply_header_access Expires allow all
4704 reply_header_access Host allow all
4705 reply_header_access If-Modified-Since allow all
4706 reply_header_access Last-Modified allow all
4707 reply_header_access Location allow all
4708 reply_header_access Pragma allow all
4709 reply_header_access Accept allow all
4710 reply_header_access Accept-Charset allow all
4711 reply_header_access Accept-Encoding allow all
4712 reply_header_access Accept-Language allow all
4713 reply_header_access Content-Language allow all
4714 reply_header_access Mime-Version allow all
4715 reply_header_access Retry-After allow all
4716 reply_header_access Title allow all
4717 reply_header_access Connection allow all
4718 reply_header_access All deny all
4720 although the HTTP request headers won't be usefully controlled
4721 by this directive -- see request_header_access for details.
4723 By default, all headers are allowed (no anonymizing is
4727 NAME: request_header_replace header_replace
4728 IFDEF: USE_HTTP_VIOLATIONS
4729 TYPE: http_header_replace[]
4730 LOC: Config.request_header_access
4733 Usage: request_header_replace header_name message
4734 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
4736 This option allows you to change the contents of headers
4737 denied with request_header_access above, by replacing them
4738 with some fixed string. This replaces the old fake_user_agent
4741 This only applies to request headers, not reply headers.
4743 By default, headers are removed if denied.
4746 NAME: reply_header_replace
4747 IFDEF: USE_HTTP_VIOLATIONS
4748 TYPE: http_header_replace[]
4749 LOC: Config.reply_header_access
4752 Usage: reply_header_replace header_name message
4753 Example: reply_header_replace Server Foo/1.0
4755 This option allows you to change the contents of headers
4756 denied with reply_header_access above, by replacing them
4757 with some fixed string.
4759 This only applies to reply headers, not request headers.
4761 By default, headers are removed if denied.
4764 NAME: relaxed_header_parser
4765 COMMENT: on|off|warn
4767 LOC: Config.onoff.relaxed_header_parser
4770 In the default "on" setting Squid accepts certain forms
4771 of non-compliant HTTP messages where it is unambiguous
4772 what the sending application intended even if the message
4773 is not correctly formatted. The messages is then normalized
4774 to the correct form when forwarded by Squid.
4776 If set to "warn" then a warning will be emitted in cache.log
4777 each time such HTTP error is encountered.
4779 If set to "off" then such HTTP errors will cause the request
4780 or response to be rejected.
4785 -----------------------------------------------------------------------------
4788 NAME: forward_timeout
4791 LOC: Config.Timeout.forward
4794 This parameter specifies how long Squid should at most attempt in
4795 finding a forwarding path for the request before giving up.
4798 NAME: connect_timeout
4801 LOC: Config.Timeout.connect
4804 This parameter specifies how long to wait for the TCP connect to
4805 the requested server or peer to complete before Squid should
4806 attempt to find another path where to forward the request.
4809 NAME: peer_connect_timeout
4812 LOC: Config.Timeout.peer_connect
4815 This parameter specifies how long to wait for a pending TCP
4816 connection to a peer cache. The default is 30 seconds. You
4817 may also set different timeout values for individual neighbors
4818 with the 'connect-timeout' option on a 'cache_peer' line.
4824 LOC: Config.Timeout.read
4827 The read_timeout is applied on server-side connections. After
4828 each successful read(), the timeout will be extended by this
4829 amount. If no data is read again after this amount of time,
4830 the request is aborted and logged with ERR_READ_TIMEOUT. The
4831 default is 15 minutes.
4837 LOC: Config.Timeout.write
4840 This timeout is tracked for all connections that have data
4841 available for writing and are waiting for the socket to become
4842 ready. After each successful write, the timeout is extended by
4843 the configured amount. If Squid has data to write but the
4844 connection is not ready for the configured duration, the
4845 transaction associated with the connection is terminated. The
4846 default is 15 minutes.
4849 NAME: request_timeout
4851 LOC: Config.Timeout.request
4854 How long to wait for complete HTTP request headers after initial
4855 connection establishment.
4858 NAME: client_idle_pconn_timeout persistent_request_timeout
4860 LOC: Config.Timeout.clientIdlePconn
4863 How long to wait for the next HTTP request on a persistent
4864 client connection after the previous request completes.
4867 NAME: client_lifetime
4870 LOC: Config.Timeout.lifetime
4873 The maximum amount of time a client (browser) is allowed to
4874 remain connected to the cache process. This protects the Cache
4875 from having a lot of sockets (and hence file descriptors) tied up
4876 in a CLOSE_WAIT state from remote clients that go away without
4877 properly shutting down (either because of a network failure or
4878 because of a poor client implementation). The default is one
4881 NOTE: The default value is intended to be much larger than any
4882 client would ever need to be connected to your cache. You
4883 should probably change client_lifetime only as a last resort.
4884 If you seem to have many client connections tying up
4885 filedescriptors, we recommend first tuning the read_timeout,
4886 request_timeout, persistent_request_timeout and quick_abort values.
4889 NAME: half_closed_clients
4891 LOC: Config.onoff.half_closed_clients
4894 Some clients may shutdown the sending side of their TCP
4895 connections, while leaving their receiving sides open. Sometimes,
4896 Squid can not tell the difference between a half-closed and a
4897 fully-closed TCP connection.
4899 By default, Squid will immediately close client connections when
4900 read(2) returns "no more data to read."
4902 Change this option to 'on' and Squid will keep open connections
4903 until a read(2) or write(2) on the socket returns an error.
4904 This may show some benefits for reverse proxies. But if not
4905 it is recommended to leave OFF.
4908 NAME: server_idle_pconn_timeout pconn_timeout
4910 LOC: Config.Timeout.serverIdlePconn
4913 Timeout for idle persistent connections to servers and other
4920 LOC: Ident::TheConfig.timeout
4923 Maximum time to wait for IDENT lookups to complete.
4925 If this is too high, and you enabled IDENT lookups from untrusted
4926 users, you might be susceptible to denial-of-service by having
4927 many ident requests going at once.
4930 NAME: shutdown_lifetime
4933 LOC: Config.shutdownLifetime
4936 When SIGTERM or SIGHUP is received, the cache is put into
4937 "shutdown pending" mode until all active sockets are closed.
4938 This value is the lifetime to set for all open descriptors
4939 during shutdown mode. Any active clients after this many
4940 seconds will receive a 'timeout' message.
4944 ADMINISTRATIVE PARAMETERS
4945 -----------------------------------------------------------------------------
4951 LOC: Config.adminEmail
4953 Email-address of local cache manager who will receive
4954 mail if the cache dies. The default is "webmaster."
4960 LOC: Config.EmailFrom
4962 From: email-address for mail sent when the cache dies.
4963 The default is to use 'appname@unique_hostname'.
4964 Default appname value is "squid", can be changed into
4965 src/globals.h before building squid.
4971 LOC: Config.EmailProgram
4973 Email program used to send mail if the cache dies.
4974 The default is "mail". The specified program must comply
4975 with the standard Unix mail syntax:
4976 mail-program recipient < mailfile
4978 Optional command line options can be specified.
4981 NAME: cache_effective_user
4983 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
4984 LOC: Config.effectiveUser
4986 If you start Squid as root, it will change its effective/real
4987 UID/GID to the user specified below. The default is to change
4988 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
4989 see also; cache_effective_group
4992 NAME: cache_effective_group
4995 LOC: Config.effectiveGroup
4997 Squid sets the GID to the effective user's default group ID
4998 (taken from the password file) and supplementary group list
4999 from the groups membership.
5001 If you want Squid to run with a specific GID regardless of
5002 the group memberships of the effective user then set this
5003 to the group (or GID) you want Squid to run as. When set
5004 all other group privileges of the effective user are ignored
5005 and only this GID is effective. If Squid is not started as
5006 root the user starting Squid MUST be member of the specified
5009 This option is not recommended by the Squid Team.
5010 Our preference is for administrators to configure a secure
5011 user account for squid with UID/GID matching system policies.
5014 NAME: httpd_suppress_version_string
5018 LOC: Config.onoff.httpd_suppress_version_string
5020 Suppress Squid version string info in HTTP headers and HTML error pages.
5023 NAME: visible_hostname
5025 LOC: Config.visibleHostname
5028 If you want to present a special hostname in error messages, etc,
5029 define this. Otherwise, the return value of gethostname()
5030 will be used. If you have multiple caches in a cluster and
5031 get errors about IP-forwarding you must set them to have individual
5032 names with this setting.
5035 NAME: unique_hostname
5037 LOC: Config.uniqueHostname
5040 If you want to have multiple machines with the same
5041 'visible_hostname' you must give each machine a different
5042 'unique_hostname' so forwarding loops can be detected.
5045 NAME: hostname_aliases
5047 LOC: Config.hostnameAliases
5050 A list of other DNS names your cache has.
5058 Minimum umask which should be enforced while the proxy
5059 is running, in addition to the umask set at startup.
5061 For a traditional octal representation of umasks, start
5066 OPTIONS FOR THE CACHE REGISTRATION SERVICE
5067 -----------------------------------------------------------------------------
5069 This section contains parameters for the (optional) cache
5070 announcement service. This service is provided to help
5071 cache administrators locate one another in order to join or
5072 create cache hierarchies.
5074 An 'announcement' message is sent (via UDP) to the registration
5075 service by Squid. By default, the announcement message is NOT
5076 SENT unless you enable it with 'announce_period' below.
5078 The announcement message includes your hostname, plus the
5079 following information from this configuration file:
5085 All current information is processed regularly and made
5086 available on the Web at http://www.ircache.net/Cache/Tracker/.
5089 NAME: announce_period
5091 LOC: Config.Announce.period
5094 This is how frequently to send cache announcements. The
5095 default is `0' which disables sending the announcement
5098 To enable announcing your cache, just set an announce period.
5101 announce_period 1 day
5106 DEFAULT: tracker.ircache.net
5107 LOC: Config.Announce.host
5113 LOC: Config.Announce.file
5119 LOC: Config.Announce.port
5121 announce_host and announce_port set the hostname and port
5122 number where the registration message will be sent.
5124 Hostname will default to 'tracker.ircache.net' and port will
5125 default default to 3131. If the 'filename' argument is given,
5126 the contents of that file will be included in the announce
5131 HTTPD-ACCELERATOR OPTIONS
5132 -----------------------------------------------------------------------------
5135 NAME: httpd_accel_surrogate_id
5138 LOC: Config.Accel.surrogate_id
5140 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
5141 need an identification token to allow control targeting. Because
5142 a farm of surrogates may all perform the same tasks, they may share
5143 an identification token.
5145 The default ID is the visible_hostname
5148 NAME: http_accel_surrogate_remote
5152 LOC: Config.onoff.surrogate_is_remote
5154 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
5155 Set this to on to have squid behave as a remote surrogate.
5159 IFDEF: USE_SQUID_ESI
5160 COMMENT: libxml2|expat|custom
5162 LOC: ESIParser::Type
5165 ESI markup is not strictly XML compatible. The custom ESI parser
5166 will give higher performance, but cannot handle non ASCII character
5171 DELAY POOL PARAMETERS
5172 -----------------------------------------------------------------------------
5176 TYPE: delay_pool_count
5178 IFDEF: USE_DELAY_POOLS
5181 This represents the number of delay pools to be used. For example,
5182 if you have one class 2 delay pool and one class 3 delays pool, you
5183 have a total of 2 delay pools.
5187 TYPE: delay_pool_class
5189 IFDEF: USE_DELAY_POOLS
5192 This defines the class of each delay pool. There must be exactly one
5193 delay_class line for each delay pool. For example, to define two
5194 delay pools, one of class 2 and one of class 3, the settings above
5198 delay_pools 4 # 4 delay pools
5199 delay_class 1 2 # pool 1 is a class 2 pool
5200 delay_class 2 3 # pool 2 is a class 3 pool
5201 delay_class 3 4 # pool 3 is a class 4 pool
5202 delay_class 4 5 # pool 4 is a class 5 pool
5204 The delay pool classes are:
5206 class 1 Everything is limited by a single aggregate
5209 class 2 Everything is limited by a single aggregate
5210 bucket as well as an "individual" bucket chosen
5211 from bits 25 through 32 of the IPv4 address.
5213 class 3 Everything is limited by a single aggregate
5214 bucket as well as a "network" bucket chosen
5215 from bits 17 through 24 of the IP address and a
5216 "individual" bucket chosen from bits 17 through
5217 32 of the IPv4 address.
5219 class 4 Everything in a class 3 delay pool, with an
5220 additional limit on a per user basis. This
5221 only takes effect if the username is established
5222 in advance - by forcing authentication in your
5225 class 5 Requests are grouped according their tag (see
5226 external_acl's tag= reply).
5229 Each pool also requires a delay_parameters directive to configure the pool size
5230 and speed limits used whenever the pool is applied to a request. Along with
5231 a set of delay_access directives to determine when it is used.
5233 NOTE: If an IP address is a.b.c.d
5234 -> bits 25 through 32 are "d"
5235 -> bits 17 through 24 are "c"
5236 -> bits 17 through 32 are "c * 256 + d"
5238 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
5239 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
5243 TYPE: delay_pool_access
5245 IFDEF: USE_DELAY_POOLS
5248 This is used to determine which delay pool a request falls into.
5250 delay_access is sorted per pool and the matching starts with pool 1,
5251 then pool 2, ..., and finally pool N. The first delay pool where the
5252 request is allowed is selected for the request. If it does not allow
5253 the request to any pool then the request is not delayed (default).
5255 For example, if you want some_big_clients in delay
5256 pool 1 and lotsa_little_clients in delay pool 2:
5259 delay_access 1 allow some_big_clients
5260 delay_access 1 deny all
5261 delay_access 2 allow lotsa_little_clients
5262 delay_access 2 deny all
5263 delay_access 3 allow authenticated_clients
5266 NAME: delay_parameters
5267 TYPE: delay_pool_rates
5269 IFDEF: USE_DELAY_POOLS
5272 This defines the parameters for a delay pool. Each delay pool has
5273 a number of "buckets" associated with it, as explained in the
5274 description of delay_class.
5276 For a class 1 delay pool, the syntax is:
5278 delay_parameters pool aggregate
5280 For a class 2 delay pool:
5282 delay_parameters pool aggregate individual
5284 For a class 3 delay pool:
5286 delay_parameters pool aggregate network individual
5288 For a class 4 delay pool:
5290 delay_parameters pool aggregate network individual user
5292 For a class 5 delay pool:
5294 delay_parameters pool tagrate
5296 The option variables are:
5298 pool a pool number - ie, a number between 1 and the
5299 number specified in delay_pools as used in
5302 aggregate the speed limit parameters for the aggregate bucket
5305 individual the speed limit parameters for the individual
5306 buckets (class 2, 3).
5308 network the speed limit parameters for the network buckets
5311 user the speed limit parameters for the user buckets
5314 tagrate the speed limit parameters for the tag buckets
5317 A pair of delay parameters is written restore/maximum, where restore is
5318 the number of bytes (not bits - modem and network speeds are usually
5319 quoted in bits) per second placed into the bucket, and maximum is the
5320 maximum number of bytes which can be in the bucket at any time.
5322 There must be one delay_parameters line for each delay pool.
5325 For example, if delay pool number 1 is a class 2 delay pool as in the
5326 above example, and is being used to strictly limit each host to 64Kbit/sec
5327 (plus overheads), with no overall limit, the line is:
5329 delay_parameters 1 -1/-1 8000/8000
5331 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
5333 Note that the figure -1 is used to represent "unlimited".
5336 And, if delay pool number 2 is a class 3 delay pool as in the above
5337 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
5338 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
5339 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
5340 to permit a decent web page to be downloaded at a decent speed
5341 (if the network is not being limited due to overuse) but slow down
5342 large downloads more significantly:
5344 delay_parameters 2 32000/32000 8000/8000 600/8000
5346 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
5347 8 x 8000 KByte/sec -> 64Kbit/sec.
5348 8 x 600 Byte/sec -> 4800bit/sec.
5351 Finally, for a class 4 delay pool as in the example - each user will
5352 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
5354 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
5357 NAME: delay_initial_bucket_level
5358 COMMENT: (percent, 0-100)
5361 IFDEF: USE_DELAY_POOLS
5362 LOC: Config.Delay.initial
5364 The initial bucket percentage is used to determine how much is put
5365 in each bucket when squid starts, is reconfigured, or first notices
5366 a host accessing it (in class 2 and class 3, individual hosts and
5367 networks only have buckets associated with them once they have been
5372 CLIENT DELAY POOL PARAMETERS
5373 -----------------------------------------------------------------------------
5376 NAME: client_delay_pools
5377 TYPE: client_delay_pool_count
5379 IFDEF: USE_DELAY_POOLS
5380 LOC: Config.ClientDelay
5382 This option specifies the number of client delay pools used. It must
5383 preceed other client_delay_* options.
5386 client_delay_pools 2
5389 NAME: client_delay_initial_bucket_level
5390 COMMENT: (percent, 0-no_limit)
5393 IFDEF: USE_DELAY_POOLS
5394 LOC: Config.ClientDelay.initial
5396 This option determines the initial bucket size as a percentage of
5397 max_bucket_size from client_delay_parameters. Buckets are created
5398 at the time of the "first" connection from the matching IP. Idle
5399 buckets are periodically deleted up.
5401 You can specify more than 100 percent but note that such "oversized"
5402 buckets are not refilled until their size goes down to max_bucket_size
5403 from client_delay_parameters.
5406 client_delay_initial_bucket_level 50
5409 NAME: client_delay_parameters
5410 TYPE: client_delay_pool_rates
5412 IFDEF: USE_DELAY_POOLS
5413 LOC: Config.ClientDelay
5416 This option configures client-side bandwidth limits using the
5419 client_delay_parameters pool speed_limit max_bucket_size
5421 pool is an integer ID used for client_delay_access matching.
5423 speed_limit is bytes added to the bucket per second.
5425 max_bucket_size is the maximum size of a bucket, enforced after any
5426 speed_limit additions.
5428 Please see the delay_parameters option for more information and
5432 client_delay_parameters 1 1024 2048
5433 client_delay_parameters 2 51200 16384
5436 NAME: client_delay_access
5437 TYPE: client_delay_pool_access
5439 IFDEF: USE_DELAY_POOLS
5440 LOC: Config.ClientDelay
5443 This option determines the client-side delay pool for the
5446 client_delay_access pool_ID allow|deny acl_name
5448 All client_delay_access options are checked in their pool ID
5449 order, starting with pool 1. The first checked pool with allowed
5450 request is selected for the request. If no ACL matches or there
5451 are no client_delay_access options, the request bandwidth is not
5454 The ACL-selected pool is then used to find the
5455 client_delay_parameters for the request. Client-side pools are
5456 not used to aggregate clients. Clients are always aggregated
5457 based on their source IP addresses (one bucket per source IP).
5459 Please see delay_access for more examples.
5462 client_delay_access 1 allow low_rate_network
5463 client_delay_access 2 allow vips_network
5467 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
5468 -----------------------------------------------------------------------------
5473 LOC: Config.Wccp.router
5477 Use this option to define your WCCP ``home'' router for
5480 wccp_router supports a single WCCP(v1) router
5482 wccp2_router supports multiple WCCPv2 routers
5484 only one of the two may be used at the same time and defines
5485 which version of WCCP to use.
5489 TYPE: IpAddress_list
5490 LOC: Config.Wccp2.router
5494 Use this option to define your WCCP ``home'' router for
5497 wccp_router supports a single WCCP(v1) router
5499 wccp2_router supports multiple WCCPv2 routers
5501 only one of the two may be used at the same time and defines
5502 which version of WCCP to use.
5507 LOC: Config.Wccp.version
5511 This directive is only relevant if you need to set up WCCP(v1)
5512 to some very old and end-of-life Cisco routers. In all other
5513 setups it must be left unset or at the default setting.
5514 It defines an internal version in the WCCP(v1) protocol,
5515 with version 4 being the officially documented protocol.
5517 According to some users, Cisco IOS 11.2 and earlier only
5518 support WCCP version 3. If you're using that or an earlier
5519 version of IOS, you may need to change this value to 3, otherwise
5520 do not specify this parameter.
5523 NAME: wccp2_rebuild_wait
5525 LOC: Config.Wccp2.rebuildwait
5529 If this is enabled Squid will wait for the cache dir rebuild to finish
5530 before sending the first wccp2 HereIAm packet
5533 NAME: wccp2_forwarding_method
5535 LOC: Config.Wccp2.forwarding_method
5539 WCCP2 allows the setting of forwarding methods between the
5540 router/switch and the cache. Valid values are as follows:
5542 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5543 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5545 Currently (as of IOS 12.4) cisco routers only support GRE.
5546 Cisco switches only support the L2 redirect assignment method.
5549 NAME: wccp2_return_method
5551 LOC: Config.Wccp2.return_method
5555 WCCP2 allows the setting of return methods between the
5556 router/switch and the cache for packets that the cache
5557 decides not to handle. Valid values are as follows:
5559 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5560 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5562 Currently (as of IOS 12.4) cisco routers only support GRE.
5563 Cisco switches only support the L2 redirect assignment.
5565 If the "ip wccp redirect exclude in" command has been
5566 enabled on the cache interface, then it is still safe for
5567 the proxy server to use a l2 redirect method even if this
5568 option is set to GRE.
5571 NAME: wccp2_assignment_method
5573 LOC: Config.Wccp2.assignment_method
5577 WCCP2 allows the setting of methods to assign the WCCP hash
5578 Valid values are as follows:
5580 hash - Hash assignment
5581 mask - Mask assignment
5583 As a general rule, cisco routers support the hash assignment method
5584 and cisco switches support the mask assignment method.
5589 LOC: Config.Wccp2.info
5590 DEFAULT_IF_NONE: standard 0
5593 WCCP2 allows for multiple traffic services. There are two
5594 types: "standard" and "dynamic". The standard type defines
5595 one service id - http (id 0). The dynamic service ids can be from
5596 51 to 255 inclusive. In order to use a dynamic service id
5597 one must define the type of traffic to be redirected; this is done
5598 using the wccp2_service_info option.
5600 The "standard" type does not require a wccp2_service_info option,
5601 just specifying the service id will suffice.
5603 MD5 service authentication can be enabled by adding
5604 "password=<password>" to the end of this service declaration.
5608 wccp2_service standard 0 # for the 'web-cache' standard service
5609 wccp2_service dynamic 80 # a dynamic service type which will be
5610 # fleshed out with subsequent options.
5611 wccp2_service standard 0 password=foo
5614 NAME: wccp2_service_info
5615 TYPE: wccp2_service_info
5616 LOC: Config.Wccp2.info
5620 Dynamic WCCPv2 services require further information to define the
5621 traffic you wish to have diverted.
5625 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
5626 priority=<priority> ports=<port>,<port>..
5628 The relevant WCCPv2 flags:
5629 + src_ip_hash, dst_ip_hash
5630 + source_port_hash, dst_port_hash
5631 + src_ip_alt_hash, dst_ip_alt_hash
5632 + src_port_alt_hash, dst_port_alt_hash
5635 The port list can be one to eight entries.
5639 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
5640 priority=240 ports=80
5642 Note: the service id must have been defined by a previous
5643 'wccp2_service dynamic <id>' entry.
5648 LOC: Config.Wccp2.weight
5652 Each cache server gets assigned a set of the destination
5653 hash proportional to their weight.
5658 LOC: Config.Wccp.address
5665 LOC: Config.Wccp2.address
5669 Use this option if you require WCCP to use a specific
5672 The default behavior is to not bind to any specific address.
5676 PERSISTENT CONNECTION HANDLING
5677 -----------------------------------------------------------------------------
5679 Also see "pconn_timeout" in the TIMEOUTS section
5682 NAME: client_persistent_connections
5684 LOC: Config.onoff.client_pconns
5688 NAME: server_persistent_connections
5690 LOC: Config.onoff.server_pconns
5693 Persistent connection support for clients and servers. By
5694 default, Squid uses persistent connections (when allowed)
5695 with its clients and servers. You can use these options to
5696 disable persistent connections with clients and/or servers.
5699 NAME: persistent_connection_after_error
5701 LOC: Config.onoff.error_pconns
5704 With this directive the use of persistent connections after
5705 HTTP errors can be disabled. Useful if you have clients
5706 who fail to handle errors on persistent connections proper.
5709 NAME: detect_broken_pconn
5711 LOC: Config.onoff.detect_broken_server_pconns
5714 Some servers have been found to incorrectly signal the use
5715 of HTTP/1.0 persistent connections even on replies not
5716 compatible, causing significant delays. This server problem
5717 has mostly been seen on redirects.
5719 By enabling this directive Squid attempts to detect such
5720 broken replies and automatically assume the reply is finished
5721 after 10 seconds timeout.
5725 CACHE DIGEST OPTIONS
5726 -----------------------------------------------------------------------------
5729 NAME: digest_generation
5730 IFDEF: USE_CACHE_DIGESTS
5732 LOC: Config.onoff.digest_generation
5735 This controls whether the server will generate a Cache Digest
5736 of its contents. By default, Cache Digest generation is
5737 enabled if Squid is compiled with --enable-cache-digests defined.
5740 NAME: digest_bits_per_entry
5741 IFDEF: USE_CACHE_DIGESTS
5743 LOC: Config.digest.bits_per_entry
5746 This is the number of bits of the server's Cache Digest which
5747 will be associated with the Digest entry for a given HTTP
5748 Method and URL (public key) combination. The default is 5.
5751 NAME: digest_rebuild_period
5752 IFDEF: USE_CACHE_DIGESTS
5755 LOC: Config.digest.rebuild_period
5758 This is the wait time between Cache Digest rebuilds.
5761 NAME: digest_rewrite_period
5763 IFDEF: USE_CACHE_DIGESTS
5765 LOC: Config.digest.rewrite_period
5768 This is the wait time between Cache Digest writes to
5772 NAME: digest_swapout_chunk_size
5775 IFDEF: USE_CACHE_DIGESTS
5776 LOC: Config.digest.swapout_chunk_size
5779 This is the number of bytes of the Cache Digest to write to
5780 disk at a time. It defaults to 4096 bytes (4KB), the Squid
5784 NAME: digest_rebuild_chunk_percentage
5785 COMMENT: (percent, 0-100)
5786 IFDEF: USE_CACHE_DIGESTS
5788 LOC: Config.digest.rebuild_chunk_percentage
5791 This is the percentage of the Cache Digest to be scanned at a
5792 time. By default it is set to 10% of the Cache Digest.
5797 -----------------------------------------------------------------------------
5802 LOC: Config.Port.snmp
5806 The port number where Squid listens for SNMP requests. To enable
5807 SNMP support set this to a suitable port number. Port number
5808 3401 is often used for the Squid SNMP agent. By default it's
5809 set to "0" (disabled)
5817 LOC: Config.accessList.snmp
5818 DEFAULT_IF_NONE: deny all
5821 Allowing or denying access to the SNMP port.
5823 All access to the agent is denied by default.
5826 snmp_access allow|deny [!]aclname ...
5828 This clause only supports fast acl types.
5829 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5831 snmp_access allow snmppublic localhost
5832 snmp_access deny all
5835 NAME: snmp_incoming_address
5837 LOC: Config.Addrs.snmp_incoming
5842 NAME: snmp_outgoing_address
5844 LOC: Config.Addrs.snmp_outgoing
5848 Just like 'udp_incoming_address', but for the SNMP port.
5850 snmp_incoming_address is used for the SNMP socket receiving
5851 messages from SNMP agents.
5852 snmp_outgoing_address is used for SNMP packets returned to SNMP
5855 The default snmp_incoming_address is to listen on all
5856 available network interfaces.
5858 If snmp_outgoing_address is not set it will use the same socket
5859 as snmp_incoming_address. Only change this if you want to have
5860 SNMP replies sent using another address than where this Squid
5861 listens for SNMP queries.
5863 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
5864 the same value since they both use port 3401.
5869 -----------------------------------------------------------------------------
5872 NAME: icp_port udp_port
5875 LOC: Config.Port.icp
5877 The port number where Squid sends and receives ICP queries to
5878 and from neighbor caches. The standard UDP port for ICP is 3130.
5879 Default is disabled (0).
5882 icp_port @DEFAULT_ICP_PORT@
5889 LOC: Config.Port.htcp
5891 The port number where Squid sends and receives HTCP queries to
5892 and from neighbor caches. To turn it on you want to set it to
5893 4827. By default it is set to "0" (disabled).
5899 NAME: log_icp_queries
5903 LOC: Config.onoff.log_udp
5905 If set, ICP queries are logged to access.log. You may wish
5906 do disable this if your ICP load is VERY high to speed things
5907 up or to simplify log analysis.
5910 NAME: udp_incoming_address
5912 LOC:Config.Addrs.udp_incoming
5915 udp_incoming_address is used for UDP packets received from other
5918 The default behavior is to not bind to any specific address.
5920 Only change this if you want to have all UDP queries received on
5921 a specific interface/address.
5923 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
5924 modules. Altering it will affect all of them in the same manner.
5926 see also; udp_outgoing_address
5928 NOTE, udp_incoming_address and udp_outgoing_address can not
5929 have the same value since they both use the same port.
5932 NAME: udp_outgoing_address
5934 LOC: Config.Addrs.udp_outgoing
5937 udp_outgoing_address is used for UDP packets sent out to other
5940 The default behavior is to not bind to any specific address.
5942 Instead it will use the same socket as udp_incoming_address.
5943 Only change this if you want to have UDP queries sent using another
5944 address than where this Squid listens for UDP queries from other
5947 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
5948 modules. Altering it will affect all of them in the same manner.
5950 see also; udp_incoming_address
5952 NOTE, udp_incoming_address and udp_outgoing_address can not
5953 have the same value since they both use the same port.
5960 LOC: Config.onoff.icp_hit_stale
5962 If you want to return ICP_HIT for stale cache objects, set this
5963 option to 'on'. If you have sibling relationships with caches
5964 in other administrative domains, this should be 'off'. If you only
5965 have sibling relationships with caches under your control,
5966 it is probably okay to set this to 'on'.
5967 If set to 'on', your siblings should use the option "allow-miss"
5968 on their cache_peer lines for connecting to you.
5971 NAME: minimum_direct_hops
5974 LOC: Config.minDirectHops
5976 If using the ICMP pinging stuff, do direct fetches for sites
5977 which are no more than this many hops away.
5980 NAME: minimum_direct_rtt
5983 LOC: Config.minDirectRtt
5985 If using the ICMP pinging stuff, do direct fetches for sites
5986 which are no more than this many rtt milliseconds away.
5992 LOC: Config.Netdb.low
5998 LOC: Config.Netdb.high
6000 The low and high water marks for the ICMP measurement
6001 database. These are counts, not percents. The defaults are
6002 900 and 1000. When the high water mark is reached, database
6003 entries will be deleted until the low mark is reached.
6006 NAME: netdb_ping_period
6008 LOC: Config.Netdb.period
6011 The minimum period for measuring a site. There will be at
6012 least this much delay between successive pings to the same
6013 network. The default is five minutes.
6020 LOC: Config.onoff.query_icmp
6022 If you want to ask your peers to include ICMP data in their ICP
6023 replies, enable this option.
6025 If your peer has configured Squid (during compilation) with
6026 '--enable-icmp' that peer will send ICMP pings to origin server
6027 sites of the URLs it receives. If you enable this option the
6028 ICP replies from that peer will include the ICMP data (if available).
6029 Then, when choosing a parent cache, Squid will choose the parent with
6030 the minimal RTT to the origin server. When this happens, the
6031 hierarchy field of the access.log will be
6032 "CLOSEST_PARENT_MISS". This option is off by default.
6035 NAME: test_reachability
6039 LOC: Config.onoff.test_reachability
6041 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
6042 instead of ICP_MISS if the target host is NOT in the ICMP
6043 database, or has a zero RTT.
6046 NAME: icp_query_timeout
6050 LOC: Config.Timeout.icp_query
6052 Normally Squid will automatically determine an optimal ICP
6053 query timeout value based on the round-trip-time of recent ICP
6054 queries. If you want to override the value determined by
6055 Squid, set this 'icp_query_timeout' to a non-zero value. This
6056 value is specified in MILLISECONDS, so, to use a 2-second
6057 timeout (the old default), you would write:
6059 icp_query_timeout 2000
6062 NAME: maximum_icp_query_timeout
6066 LOC: Config.Timeout.icp_query_max
6068 Normally the ICP query timeout is determined dynamically. But
6069 sometimes it can lead to very large values (say 5 seconds).
6070 Use this option to put an upper limit on the dynamic timeout
6071 value. Do NOT use this option to always use a fixed (instead
6072 of a dynamic) timeout value. To set a fixed timeout see the
6073 'icp_query_timeout' directive.
6076 NAME: minimum_icp_query_timeout
6080 LOC: Config.Timeout.icp_query_min
6082 Normally the ICP query timeout is determined dynamically. But
6083 sometimes it can lead to very small timeouts, even lower than
6084 the normal latency variance on your link due to traffic.
6085 Use this option to put an lower limit on the dynamic timeout
6086 value. Do NOT use this option to always use a fixed (instead
6087 of a dynamic) timeout value. To set a fixed timeout see the
6088 'icp_query_timeout' directive.
6091 NAME: background_ping_rate
6095 LOC: Config.backgroundPingRate
6097 Controls how often the ICP pings are sent to siblings that
6098 have background-ping set.
6102 MULTICAST ICP OPTIONS
6103 -----------------------------------------------------------------------------
6108 LOC: Config.mcast_group_list
6111 This tag specifies a list of multicast groups which your server
6112 should join to receive multicasted ICP queries.
6114 NOTE! Be very careful what you put here! Be sure you
6115 understand the difference between an ICP _query_ and an ICP
6116 _reply_. This option is to be set only if you want to RECEIVE
6117 multicast queries. Do NOT set this option to SEND multicast
6118 ICP (use cache_peer for that). ICP replies are always sent via
6119 unicast, so this option does not affect whether or not you will
6120 receive replies from multicast group members.
6122 You must be very careful to NOT use a multicast address which
6123 is already in use by another group of caches.
6125 If you are unsure about multicast, please read the Multicast
6126 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
6128 Usage: mcast_groups 239.128.16.128 224.0.1.20
6130 By default, Squid doesn't listen on any multicast groups.
6133 NAME: mcast_miss_addr
6134 IFDEF: MULTICAST_MISS_STREAM
6136 LOC: Config.mcast_miss.addr
6139 If you enable this option, every "cache miss" URL will
6140 be sent out on the specified multicast address.
6142 Do not enable this option unless you are are absolutely
6143 certain you understand what you are doing.
6146 NAME: mcast_miss_ttl
6147 IFDEF: MULTICAST_MISS_STREAM
6149 LOC: Config.mcast_miss.ttl
6152 This is the time-to-live value for packets multicasted
6153 when multicasting off cache miss URLs is enabled. By
6154 default this is set to 'site scope', i.e. 16.
6157 NAME: mcast_miss_port
6158 IFDEF: MULTICAST_MISS_STREAM
6160 LOC: Config.mcast_miss.port
6163 This is the port number to be used in conjunction with
6167 NAME: mcast_miss_encode_key
6168 IFDEF: MULTICAST_MISS_STREAM
6170 LOC: Config.mcast_miss.encode_key
6171 DEFAULT: XXXXXXXXXXXXXXXX
6173 The URLs that are sent in the multicast miss stream are
6174 encrypted. This is the encryption key.
6177 NAME: mcast_icp_query_timeout
6181 LOC: Config.Timeout.mcast_icp_query
6183 For multicast peers, Squid regularly sends out ICP "probes" to
6184 count how many other peers are listening on the given multicast
6185 address. This value specifies how long Squid should wait to
6186 count all the replies. The default is 2000 msec, or 2
6191 INTERNAL ICON OPTIONS
6192 -----------------------------------------------------------------------------
6195 NAME: icon_directory
6197 LOC: Config.icons.directory
6198 DEFAULT: @DEFAULT_ICON_DIR@
6200 Where the icons are stored. These are normally kept in
6204 NAME: global_internal_static
6206 LOC: Config.onoff.global_internal_static
6209 This directive controls is Squid should intercept all requests for
6210 /squid-internal-static/ no matter which host the URL is requesting
6211 (default on setting), or if nothing special should be done for
6212 such URLs (off setting). The purpose of this directive is to make
6213 icons etc work better in complex cache hierarchies where it may
6214 not always be possible for all corners in the cache mesh to reach
6215 the server generating a directory listing.
6218 NAME: short_icon_urls
6220 LOC: Config.icons.use_short_names
6223 If this is enabled Squid will use short URLs for icons.
6224 If disabled it will revert to the old behavior of including
6225 it's own name and port in the URL.
6227 If you run a complex cache hierarchy with a mix of Squid and
6228 other proxies you may need to disable this directive.
6233 -----------------------------------------------------------------------------
6236 NAME: error_directory
6238 LOC: Config.errorDirectory
6241 If you wish to create your own versions of the default
6242 error files to customize them to suit your company copy
6243 the error/template files to another directory and point
6246 WARNING: This option will disable multi-language support
6247 on error pages if used.
6249 The squid developers are interested in making squid available in
6250 a wide variety of languages. If you are making translations for a
6251 language that Squid does not currently provide please consider
6252 contributing your translation back to the project.
6253 http://wiki.squid-cache.org/Translations
6255 The squid developers working on translations are happy to supply drop-in
6256 translated error files in exchange for any new language contributions.
6259 NAME: error_default_language
6260 IFDEF: USE_ERR_LOCALES
6262 LOC: Config.errorDefaultLanguage
6265 Set the default language which squid will send error pages in
6266 if no existing translation matches the clients language
6269 If unset (default) generic English will be used.
6271 The squid developers are interested in making squid available in
6272 a wide variety of languages. If you are interested in making
6273 translations for any language see the squid wiki for details.
6274 http://wiki.squid-cache.org/Translations
6277 NAME: error_log_languages
6278 IFDEF: USE_ERR_LOCALES
6280 LOC: Config.errorLogMissingLanguages
6283 Log to cache.log what languages users are attempting to
6284 auto-negotiate for translations.
6286 Successful negotiations are not logged. Only failures
6287 have meaning to indicate that Squid may need an upgrade
6288 of its error page translations.
6291 NAME: err_page_stylesheet
6293 LOC: Config.errorStylesheet
6294 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
6296 CSS Stylesheet to pattern the display of Squid default error pages.
6298 For information on CSS see http://www.w3.org/Style/CSS/
6303 LOC: Config.errHtmlText
6306 HTML text to include in error messages. Make this a "mailto"
6307 URL to your admin address, or maybe just a link to your
6308 organizations Web page.
6310 To include this in your error messages, you must rewrite
6311 the error template files (found in the "errors" directory).
6312 Wherever you want the 'err_html_text' line to appear,
6313 insert a %L tag in the error template file.
6316 NAME: email_err_data
6319 LOC: Config.onoff.emailErrData
6322 If enabled, information about the occurred error will be
6323 included in the mailto links of the ERR pages (if %W is set)
6324 so that the email body contains the data.
6325 Syntax is <A HREF="mailto:%w%W">%w</A>
6330 LOC: Config.denyInfoList
6333 Usage: deny_info err_page_name acl
6334 or deny_info http://... acl
6335 or deny_info TCP_RESET acl
6337 This can be used to return a ERR_ page for requests which
6338 do not pass the 'http_access' rules. Squid remembers the last
6339 acl it evaluated in http_access, and if a 'deny_info' line exists
6340 for that ACL Squid returns a corresponding error page.
6342 The acl is typically the last acl on the http_access deny line which
6343 denied access. The exceptions to this rule are:
6344 - When Squid needs to request authentication credentials. It's then
6345 the first authentication related acl encountered
6346 - When none of the http_access lines matches. It's then the last
6347 acl processed on the last http_access line.
6348 - When the decision to deny access was made by an adaptation service,
6349 the acl name is the corresponding eCAP or ICAP service_name.
6351 NP: If providing your own custom error pages with error_directory
6352 you may also specify them by your custom file name:
6353 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
6355 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
6356 may be specified by prefixing the file name with the code and a colon.
6357 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
6359 Alternatively you can tell Squid to reset the TCP connection
6360 by specifying TCP_RESET.
6362 Or you can specify an error URL or URL pattern. The browsers will
6363 get redirected to the specified URL after formatting tags have
6364 been replaced. Redirect will be done with 302 or 307 according to
6365 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
6366 the URL. e.g. 303:http://example.com/
6369 %a - username (if available. Password NOT included)
6372 %E - Error description
6374 %H - Request domain name
6375 %i - Client IP Address
6377 %o - Message result from external ACL helper
6378 %p - Request Port number
6379 %P - Request Protocol name
6380 %R - Request URL path
6381 %T - Timestamp in RFC 1123 format
6382 %U - Full canonical URL from client
6383 (HTTPS URLs terminate with *)
6384 %u - Full canonical URL from client
6385 %w - Admin email from squid.conf
6387 %% - Literal percent (%) code
6392 OPTIONS INFLUENCING REQUEST FORWARDING
6393 -----------------------------------------------------------------------------
6396 NAME: nonhierarchical_direct
6398 LOC: Config.onoff.nonhierarchical_direct
6401 By default, Squid will send any non-hierarchical requests
6402 (matching hierarchy_stoplist or not cacheable request type) direct
6405 If you set this to off, Squid will prefer to send these
6406 requests to parents.
6408 Note that in most configurations, by turning this off you will only
6409 add latency to these request without any improvement in global hit
6412 If you are inside an firewall see never_direct instead of
6418 LOC: Config.onoff.prefer_direct
6421 Normally Squid tries to use parents for most requests. If you for some
6422 reason like it to first try going direct and only use a parent if
6423 going direct fails set this to on.
6425 By combining nonhierarchical_direct off and prefer_direct on you
6426 can set up Squid to use a parent as a backup path if going direct
6429 Note: If you want Squid to use parents for all requests see
6430 the never_direct directive. prefer_direct only modifies how Squid
6431 acts on cacheable requests.
6436 LOC: Config.accessList.AlwaysDirect
6439 Usage: always_direct allow|deny [!]aclname ...
6441 Here you can use ACL elements to specify requests which should
6442 ALWAYS be forwarded by Squid to the origin servers without using
6443 any peers. For example, to always directly forward requests for
6444 local servers ignoring any parents or siblings you may have use
6447 acl local-servers dstdomain my.domain.net
6448 always_direct allow local-servers
6450 To always forward FTP requests directly, use
6453 always_direct allow FTP
6455 NOTE: There is a similar, but opposite option named
6456 'never_direct'. You need to be aware that "always_direct deny
6457 foo" is NOT the same thing as "never_direct allow foo". You
6458 may need to use a deny rule to exclude a more-specific case of
6459 some other rule. Example:
6461 acl local-external dstdomain external.foo.net
6462 acl local-servers dstdomain .foo.net
6463 always_direct deny local-external
6464 always_direct allow local-servers
6466 NOTE: If your goal is to make the client forward the request
6467 directly to the origin server bypassing Squid then this needs
6468 to be done in the client configuration. Squid configuration
6469 can only tell Squid how Squid should fetch the object.
6471 NOTE: This directive is not related to caching. The replies
6472 is cached as usual even if you use always_direct. To not cache
6473 the replies see the 'cache' directive.
6475 This clause supports both fast and slow acl types.
6476 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6481 LOC: Config.accessList.NeverDirect
6484 Usage: never_direct allow|deny [!]aclname ...
6486 never_direct is the opposite of always_direct. Please read
6487 the description for always_direct if you have not already.
6489 With 'never_direct' you can use ACL elements to specify
6490 requests which should NEVER be forwarded directly to origin
6491 servers. For example, to force the use of a proxy for all
6492 requests, except those in your local domain use something like:
6494 acl local-servers dstdomain .foo.net
6495 never_direct deny local-servers
6496 never_direct allow all
6498 or if Squid is inside a firewall and there are local intranet
6499 servers inside the firewall use something like:
6501 acl local-intranet dstdomain .foo.net
6502 acl local-external dstdomain external.foo.net
6503 always_direct deny local-external
6504 always_direct allow local-intranet
6505 never_direct allow all
6507 This clause supports both fast and slow acl types.
6508 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6512 ADVANCED NETWORKING OPTIONS
6513 -----------------------------------------------------------------------------
6516 NAME: incoming_icp_average
6519 LOC: Config.comm_incoming.icp_average
6522 NAME: incoming_http_average
6525 LOC: Config.comm_incoming.http_average
6528 NAME: incoming_dns_average
6531 LOC: Config.comm_incoming.dns_average
6534 NAME: min_icp_poll_cnt
6537 LOC: Config.comm_incoming.icp_min_poll
6540 NAME: min_dns_poll_cnt
6543 LOC: Config.comm_incoming.dns_min_poll
6546 NAME: min_http_poll_cnt
6549 LOC: Config.comm_incoming.http_min_poll
6551 Heavy voodoo here. I can't even believe you are reading this.
6552 Are you crazy? Don't even think about adjusting these unless
6553 you understand the algorithms in comm_select.c first!
6559 LOC: Config.accept_filter
6563 The name of an accept(2) filter to install on Squid's
6564 listen socket(s). This feature is perhaps specific to
6565 FreeBSD and requires support in the kernel.
6567 The 'httpready' filter delays delivering new connections
6568 to Squid until a full HTTP request has been received.
6569 See the accf_http(9) man page for details.
6571 The 'dataready' filter delays delivering new connections
6572 to Squid until there is some data to process.
6573 See the accf_dataready(9) man page for details.
6577 The 'data' filter delays delivering of new connections
6578 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
6579 You may optionally specify a number of seconds to wait by
6580 'data=N' where N is the number of seconds. Defaults to 30
6581 if not specified. See the tcp(7) man page for details.
6584 accept_filter httpready
6589 NAME: client_ip_max_connections
6591 LOC: Config.client_ip_max_connections
6594 Set an absolute limit on the number of connections a single
6595 client IP can use. Any more than this and Squid will begin to drop
6596 new connections from the client until it closes some links.
6598 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
6599 connections from the client. For finer control use the ACL access controls.
6601 Requires client_db to be enabled (the default).
6603 WARNING: This may noticably slow down traffic received via external proxies
6604 or NAT devices and cause them to rebound error messages back to their clients.
6607 NAME: tcp_recv_bufsize
6611 LOC: Config.tcpRcvBufsz
6613 Size of receive buffer to set for TCP sockets. Probably just
6614 as easy to change your kernel's default. Set to zero to use
6615 the default buffer size.
6620 -----------------------------------------------------------------------------
6627 LOC: Adaptation::Icap::TheConfig.onoff
6630 If you want to enable the ICAP module support, set this to on.
6633 NAME: icap_connect_timeout
6636 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
6639 This parameter specifies how long to wait for the TCP connect to
6640 the requested ICAP server to complete before giving up and either
6641 terminating the HTTP transaction or bypassing the failure.
6643 The default for optional services is peer_connect_timeout.
6644 The default for essential services is connect_timeout.
6645 If this option is explicitly set, its value applies to all services.
6648 NAME: icap_io_timeout
6652 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
6655 This parameter specifies how long to wait for an I/O activity on
6656 an established, active ICAP connection before giving up and
6657 either terminating the HTTP transaction or bypassing the
6660 The default is read_timeout.
6663 NAME: icap_service_failure_limit
6664 COMMENT: limit [in memory-depth time-units]
6665 TYPE: icap_service_failure_limit
6667 LOC: Adaptation::Icap::TheConfig
6670 The limit specifies the number of failures that Squid tolerates
6671 when establishing a new TCP connection with an ICAP service. If
6672 the number of failures exceeds the limit, the ICAP service is
6673 not used for new ICAP requests until it is time to refresh its
6676 A negative value disables the limit. Without the limit, an ICAP
6677 service will not be considered down due to connectivity failures
6678 between ICAP OPTIONS requests.
6680 Squid forgets ICAP service failures older than the specified
6681 value of memory-depth. The memory fading algorithm
6682 is approximate because Squid does not remember individual
6683 errors but groups them instead, splitting the option
6684 value into ten time slots of equal length.
6686 When memory-depth is 0 and by default this option has no
6687 effect on service failure expiration.
6689 Squid always forgets failures when updating service settings
6690 using an ICAP OPTIONS transaction, regardless of this option
6694 # suspend service usage after 10 failures in 5 seconds:
6695 icap_service_failure_limit 10 in 5 seconds
6698 NAME: icap_service_revival_delay
6701 LOC: Adaptation::Icap::TheConfig.service_revival_delay
6704 The delay specifies the number of seconds to wait after an ICAP
6705 OPTIONS request failure before requesting the options again. The
6706 failed ICAP service is considered "down" until fresh OPTIONS are
6709 The actual delay cannot be smaller than the hardcoded minimum
6710 delay of 30 seconds.
6713 NAME: icap_preview_enable
6717 LOC: Adaptation::Icap::TheConfig.preview_enable
6720 The ICAP Preview feature allows the ICAP server to handle the
6721 HTTP message by looking only at the beginning of the message body
6722 or even without receiving the body at all. In some environments,
6723 previews greatly speedup ICAP processing.
6725 During an ICAP OPTIONS transaction, the server may tell Squid what
6726 HTTP messages should be previewed and how big the preview should be.
6727 Squid will not use Preview if the server did not request one.
6729 To disable ICAP Preview for all ICAP services, regardless of
6730 individual ICAP server OPTIONS responses, set this option to "off".
6732 icap_preview_enable off
6735 NAME: icap_preview_size
6738 LOC: Adaptation::Icap::TheConfig.preview_size
6741 The default size of preview data to be sent to the ICAP server.
6742 -1 means no preview. This value might be overwritten on a per server
6743 basis by OPTIONS requests.
6746 NAME: icap_206_enable
6750 LOC: Adaptation::Icap::TheConfig.allow206_enable
6753 206 (Partial Content) responses is an ICAP extension that allows the
6754 ICAP agents to optionally combine adapted and original HTTP message
6755 content. The decision to combine is postponed until the end of the
6756 ICAP response. Squid supports Partial Content extension by default.
6758 Activation of the Partial Content extension is negotiated with each
6759 ICAP service during OPTIONS exchange. Most ICAP servers should handle
6760 negotation correctly even if they do not support the extension, but
6761 some might fail. To disable Partial Content support for all ICAP
6762 services and to avoid any negotiation, set this option to "off".
6768 NAME: icap_default_options_ttl
6771 LOC: Adaptation::Icap::TheConfig.default_options_ttl
6774 The default TTL value for ICAP OPTIONS responses that don't have
6775 an Options-TTL header.
6778 NAME: icap_persistent_connections
6782 LOC: Adaptation::Icap::TheConfig.reuse_connections
6785 Whether or not Squid should use persistent connections to
6789 NAME: adaptation_send_client_ip icap_send_client_ip
6791 IFDEF: USE_ADAPTATION
6793 LOC: Adaptation::Config::send_client_ip
6796 If enabled, Squid shares HTTP client IP information with adaptation
6797 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
6798 For eCAP, Squid sets the libecap::metaClientIp transaction option.
6800 See also: adaptation_uses_indirect_client
6803 NAME: adaptation_send_username icap_send_client_username
6805 IFDEF: USE_ADAPTATION
6807 LOC: Adaptation::Config::send_username
6810 This sends authenticated HTTP client username (if available) to
6811 the adaptation service.
6813 For ICAP, the username value is encoded based on the
6814 icap_client_username_encode option and is sent using the header
6815 specified by the icap_client_username_header option.
6818 NAME: icap_client_username_header
6821 LOC: Adaptation::Icap::TheConfig.client_username_header
6822 DEFAULT: X-Client-Username
6824 ICAP request header name to use for adaptation_send_username.
6827 NAME: icap_client_username_encode
6831 LOC: Adaptation::Icap::TheConfig.client_username_encode
6834 Whether to base64 encode the authenticated client username.
6838 TYPE: icap_service_type
6840 LOC: Adaptation::Icap::TheConfig
6843 Defines a single ICAP service using the following format:
6845 icap_service id vectoring_point uri [option ...]
6848 an opaque identifier or name which is used to direct traffic to
6849 this specific service. Must be unique among all adaptation
6850 services in squid.conf.
6852 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6853 This specifies at which point of transaction processing the
6854 ICAP service should be activated. *_postcache vectoring points
6855 are not yet supported.
6857 uri: icap://servername:port/servicepath
6858 ICAP server and service location.
6860 ICAP does not allow a single service to handle both REQMOD and RESPMOD
6861 transactions. Squid does not enforce that requirement. You can specify
6862 services with the same service_url and different vectoring_points. You
6863 can even specify multiple identical services as long as their
6864 service_names differ.
6867 Service options are separated by white space. ICAP services support
6868 the following name=value options:
6871 If set to 'on' or '1', the ICAP service is treated as
6872 optional. If the service cannot be reached or malfunctions,
6873 Squid will try to ignore any errors and process the message as
6874 if the service was not enabled. No all ICAP errors can be
6875 bypassed. If set to 0, the ICAP service is treated as
6876 essential and all ICAP errors will result in an error page
6877 returned to the HTTP client.
6879 Bypass is off by default: services are treated as essential.
6882 If set to 'on' or '1', the ICAP service is allowed to
6883 dynamically change the current message adaptation plan by
6884 returning a chain of services to be used next. The services
6885 are specified using the X-Next-Services ICAP response header
6886 value, formatted as a comma-separated list of service names.
6887 Each named service should be configured in squid.conf. Other
6888 services are ignored. An empty X-Next-Services value results
6889 in an empty plan which ends the current adaptation.
6891 Dynamic adaptation plan may cross or cover multiple supported
6892 vectoring points in their natural processing order.
6894 Routing is not allowed by default: the ICAP X-Next-Services
6895 response header is ignored.
6898 Only has effect on split-stack systems. The default on those systems
6899 is to use IPv4-only connections. When set to 'on' this option will
6900 make Squid use IPv6-only connections to contact this ICAP service.
6902 on-overload=block|bypass|wait|force
6903 If the service Max-Connections limit has been reached, do
6904 one of the following for each new ICAP transaction:
6905 * block: send an HTTP error response to the client
6906 * bypass: ignore the "over-connected" ICAP service
6907 * wait: wait (in a FIFO queue) for an ICAP connection slot
6908 * force: proceed, ignoring the Max-Connections limit
6910 In SMP mode with N workers, each worker assumes the service
6911 connection limit is Max-Connections/N, even though not all
6912 workers may use a given service.
6914 The default value is "bypass" if service is bypassable,
6915 otherwise it is set to "wait".
6919 Use the given number as the Max-Connections limit, regardless
6920 of the Max-Connections value given by the service, if any.
6922 Older icap_service format without optional named parameters is
6923 deprecated but supported for backward compatibility.
6926 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
6927 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
6931 TYPE: icap_class_type
6936 This deprecated option was documented to define an ICAP service
6937 chain, even though it actually defined a set of similar, redundant
6938 services, and the chains were not supported.
6940 To define a set of redundant services, please use the
6941 adaptation_service_set directive. For service chains, use
6942 adaptation_service_chain.
6946 TYPE: icap_access_type
6951 This option is deprecated. Please use adaptation_access, which
6952 has the same ICAP functionality, but comes with better
6953 documentation, and eCAP support.
6958 -----------------------------------------------------------------------------
6965 LOC: Adaptation::Ecap::TheConfig.onoff
6968 Controls whether eCAP support is enabled.
6972 TYPE: ecap_service_type
6974 LOC: Adaptation::Ecap::TheConfig
6977 Defines a single eCAP service
6979 ecap_service id vectoring_point uri [option ...]
6982 an opaque identifier or name which is used to direct traffic to
6983 this specific service. Must be unique among all adaptation
6984 services in squid.conf.
6986 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6987 This specifies at which point of transaction processing the
6988 eCAP service should be activated. *_postcache vectoring points
6989 are not yet supported.
6991 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
6992 Squid uses the eCAP service URI to match this configuration
6993 line with one of the dynamically loaded services. Each loaded
6994 eCAP service must have a unique URI. Obtain the right URI from
6995 the service provider.
6998 Service options are separated by white space. eCAP services support
6999 the following name=value options:
7002 If set to 'on' or '1', the eCAP service is treated as optional.
7003 If the service cannot be reached or malfunctions, Squid will try
7004 to ignore any errors and process the message as if the service
7005 was not enabled. No all eCAP errors can be bypassed.
7006 If set to 'off' or '0', the eCAP service is treated as essential
7007 and all eCAP errors will result in an error page returned to the
7010 Bypass is off by default: services are treated as essential.
7013 If set to 'on' or '1', the eCAP service is allowed to
7014 dynamically change the current message adaptation plan by
7015 returning a chain of services to be used next.
7017 Dynamic adaptation plan may cross or cover multiple supported
7018 vectoring points in their natural processing order.
7020 Routing is not allowed by default.
7022 Older ecap_service format without optional named parameters is
7023 deprecated but supported for backward compatibility.
7027 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
7028 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
7031 NAME: loadable_modules
7033 IFDEF: USE_LOADABLE_MODULES
7034 LOC: Config.loadable_module_names
7037 Instructs Squid to load the specified dynamic module(s) or activate
7038 preloaded module(s).
7040 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
7044 MESSAGE ADAPTATION OPTIONS
7045 -----------------------------------------------------------------------------
7048 NAME: adaptation_service_set
7049 TYPE: adaptation_service_set_type
7050 IFDEF: USE_ADAPTATION
7055 Configures an ordered set of similar, redundant services. This is
7056 useful when hot standby or backup adaptation servers are available.
7058 adaptation_service_set set_name service_name1 service_name2 ...
7060 The named services are used in the set declaration order. The first
7061 applicable adaptation service from the set is used first. The next
7062 applicable service is tried if and only if the transaction with the
7063 previous service fails and the message waiting to be adapted is still
7066 When adaptation starts, broken services are ignored as if they were
7067 not a part of the set. A broken service is a down optional service.
7069 The services in a set must be attached to the same vectoring point
7070 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7072 If all services in a set are optional then adaptation failures are
7073 bypassable. If all services in the set are essential, then a
7074 transaction failure with one service may still be retried using
7075 another service from the set, but when all services fail, the master
7076 transaction fails as well.
7078 A set may contain a mix of optional and essential services, but that
7079 is likely to lead to surprising results because broken services become
7080 ignored (see above), making previously bypassable failures fatal.
7081 Technically, it is the bypassability of the last failed service that
7084 See also: adaptation_access adaptation_service_chain
7087 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
7088 adaptation service_set svcLogger loggerLocal loggerRemote
7091 NAME: adaptation_service_chain
7092 TYPE: adaptation_service_chain_type
7093 IFDEF: USE_ADAPTATION
7098 Configures a list of complementary services that will be applied
7099 one-by-one, forming an adaptation chain or pipeline. This is useful
7100 when Squid must perform different adaptations on the same message.
7102 adaptation_service_chain chain_name service_name1 svc_name2 ...
7104 The named services are used in the chain declaration order. The first
7105 applicable adaptation service from the chain is used first. The next
7106 applicable service is applied to the successful adaptation results of
7107 the previous service in the chain.
7109 When adaptation starts, broken services are ignored as if they were
7110 not a part of the chain. A broken service is a down optional service.
7112 Request satisfaction terminates the adaptation chain because Squid
7113 does not currently allow declaration of RESPMOD services at the
7114 "reqmod_precache" vectoring point (see icap_service or ecap_service).
7116 The services in a chain must be attached to the same vectoring point
7117 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7119 A chain may contain a mix of optional and essential services. If an
7120 essential adaptation fails (or the failure cannot be bypassed for
7121 other reasons), the master transaction fails. Otherwise, the failure
7122 is bypassed as if the failed adaptation service was not in the chain.
7124 See also: adaptation_access adaptation_service_set
7127 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
7130 NAME: adaptation_access
7131 TYPE: adaptation_access_type
7132 IFDEF: USE_ADAPTATION
7136 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
7138 adaptation_access service_name allow|deny [!]aclname...
7139 adaptation_access set_name allow|deny [!]aclname...
7141 At each supported vectoring point, the adaptation_access
7142 statements are processed in the order they appear in this
7143 configuration file. Statements pointing to the following services
7144 are ignored (i.e., skipped without checking their ACL):
7146 - services serving different vectoring points
7147 - "broken-but-bypassable" services
7148 - "up" services configured to ignore such transactions
7149 (e.g., based on the ICAP Transfer-Ignore header).
7151 When a set_name is used, all services in the set are checked
7152 using the same rules, to find the first applicable one. See
7153 adaptation_service_set for details.
7155 If an access list is checked and there is a match, the
7156 processing stops: For an "allow" rule, the corresponding
7157 adaptation service is used for the transaction. For a "deny"
7158 rule, no adaptation service is activated.
7160 It is currently not possible to apply more than one adaptation
7161 service at the same vectoring point to the same HTTP transaction.
7163 See also: icap_service and ecap_service
7166 adaptation_access service_1 allow all
7169 NAME: adaptation_service_iteration_limit
7171 IFDEF: USE_ADAPTATION
7172 LOC: Adaptation::Config::service_iteration_limit
7175 Limits the number of iterations allowed when applying adaptation
7176 services to a message. If your longest adaptation set or chain
7177 may have more than 16 services, increase the limit beyond its
7178 default value of 16. If detecting infinite iteration loops sooner
7179 is critical, make the iteration limit match the actual number
7180 of services in your longest adaptation set or chain.
7182 Infinite adaptation loops are most likely with routing services.
7184 See also: icap_service routing=1
7187 NAME: adaptation_masterx_shared_names
7189 IFDEF: USE_ADAPTATION
7190 LOC: Adaptation::Config::masterx_shared_name
7193 For each master transaction (i.e., the HTTP request and response
7194 sequence, including all related ICAP and eCAP exchanges), Squid
7195 maintains a table of metadata. The table entries are (name, value)
7196 pairs shared among eCAP and ICAP exchanges. The table is destroyed
7197 with the master transaction.
7199 This option specifies the table entry names that Squid must accept
7200 from and forward to the adaptation transactions.
7202 An ICAP REQMOD or RESPMOD transaction may set an entry in the
7203 shared table by returning an ICAP header field with a name
7204 specified in adaptation_masterx_shared_names.
7206 An eCAP REQMOD or RESPMOD transaction may set an entry in the
7207 shared table by implementing the libecap::visitEachOption() API
7208 to provide an option with a name specified in
7209 adaptation_masterx_shared_names.
7211 Squid will store and forward the set entry to subsequent adaptation
7212 transactions within the same master transaction scope.
7214 Only one shared entry name is supported at this time.
7217 # share authentication information among ICAP services
7218 adaptation_masterx_shared_names X-Subscriber-ID
7221 NAME: adaptation_meta
7222 TYPE: adaptation_meta_type
7223 IFDEF: USE_ADAPTATION
7224 LOC: Adaptation::Config::metaHeaders
7227 This option allows Squid administrator to add custom ICAP request
7228 headers or eCAP options to Squid ICAP requests or eCAP transactions.
7229 Use it to pass custom authentication tokens and other
7230 transaction-state related meta information to an ICAP/eCAP service.
7232 The addition of a meta header is ACL-driven:
7233 adaptation_meta name value [!]aclname ...
7235 Processing for a given header name stops after the first ACL list match.
7236 Thus, it is impossible to add two headers with the same name. If no ACL
7237 lists match for a given header name, no such header is added. For
7240 # do not debug transactions except for those that need debugging
7241 adaptation_meta X-Debug 1 needs_debugging
7243 # log all transactions except for those that must remain secret
7244 adaptation_meta X-Log 1 !keep_secret
7246 # mark transactions from users in the "G 1" group
7247 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
7249 The "value" parameter may be a regular squid.conf token or a "double
7250 quoted string". Within the quoted string, use backslash (\) to escape
7251 any character, which is currently only useful for escaping backslashes
7252 and double quotes. For example,
7253 "this string has one backslash (\\) and two \"quotes\""
7259 LOC: Adaptation::Icap::TheConfig.repeat
7260 DEFAULT_IF_NONE: deny all
7262 This ACL determines which retriable ICAP transactions are
7263 retried. Transactions that received a complete ICAP response
7264 and did not have to consume or produce HTTP bodies to receive
7265 that response are usually retriable.
7267 icap_retry allow|deny [!]aclname ...
7269 Squid automatically retries some ICAP I/O timeouts and errors
7270 due to persistent connection race conditions.
7272 See also: icap_retry_limit
7275 NAME: icap_retry_limit
7278 LOC: Adaptation::Icap::TheConfig.repeat_limit
7281 Limits the number of retries allowed. When set to zero (default),
7282 no retries are allowed.
7284 Communication errors due to persistent connection race
7285 conditions are unavoidable, automatically retried, and do not
7286 count against this limit.
7288 See also: icap_retry
7294 -----------------------------------------------------------------------------
7297 NAME: check_hostnames
7300 LOC: Config.onoff.check_hostnames
7302 For security and stability reasons Squid can check
7303 hostnames for Internet standard RFC compliance. If you want
7304 Squid to perform these checks turn this directive on.
7307 NAME: allow_underscore
7310 LOC: Config.onoff.allow_underscore
7312 Underscore characters is not strictly allowed in Internet hostnames
7313 but nevertheless used by many sites. Set this to off if you want
7314 Squid to be strict about the standard.
7315 This check is performed only when check_hostnames is set to on.
7318 NAME: cache_dns_program
7320 IFDEF: USE_DNSHELPER
7321 DEFAULT: @DEFAULT_DNSSERVER@
7322 LOC: Config.Program.dnsserver
7324 Specify the location of the executable for dnslookup process.
7328 TYPE: HelperChildConfig
7329 IFDEF: USE_DNSHELPER
7330 DEFAULT: 32 startup=1 idle=1
7331 LOC: Config.dnsChildren
7333 The maximum number of processes spawn to service DNS name lookups.
7334 If you limit it too few Squid will have to wait for them to process
7335 a backlog of requests, slowing it down. If you allow too many they
7336 will use RAM and other system resources noticably.
7337 The maximum this may be safely set to is 32.
7339 The startup= and idle= options allow some measure of skew in your
7344 Sets a minimum of how many processes are to be spawned when Squid
7345 starts or reconfigures. When set to zero the first request will
7346 cause spawning of the first child process to handle it.
7348 Starting too few will cause an initial slowdown in traffic as Squid
7349 attempts to simultaneously spawn enough processes to cope.
7353 Sets a minimum of how many processes Squid is to try and keep available
7354 at all times. When traffic begins to rise above what the existing
7355 processes can handle this many more will be spawned up to the maximum
7356 configured. A minimum setting of 1 is required.
7359 NAME: dns_retransmit_interval
7362 LOC: Config.Timeout.idns_retransmit
7363 IFDEF: !USE_DNSHELPER
7365 Initial retransmit interval for DNS queries. The interval is
7366 doubled each time all configured DNS servers have been tried.
7372 LOC: Config.Timeout.idns_query
7373 IFDEF: !USE_DNSHELPER
7375 DNS Query timeout. If no response is received to a DNS query
7376 within this time all DNS servers for the queried domain
7377 are assumed to be unavailable.
7380 NAME: dns_packet_max
7383 LOC: Config.dns.packet_max
7384 IFDEF: !USE_DNSHELPER
7386 Maximum number of bytes packet size to advertise via EDNS.
7387 Set to "none" to disable EDNS large packet support.
7389 For legacy reasons DNS UDP replies will default to 512 bytes which
7390 is too small for many responses. EDNS provides a means for Squid to
7391 negotiate receiving larger responses back immediately without having
7392 to failover with repeat requests. Responses larger than this limit
7393 will retain the old behaviour of failover to TCP DNS.
7395 Squid has no real fixed limit internally, but allowing packet sizes
7396 over 1500 bytes requires network jumbogram support and is usually not
7399 WARNING: The RFC also indicates that some older resolvers will reply
7400 with failure of the whole request if the extension is added. Some
7401 resolvers have already been identified which will reply with mangled
7402 EDNS response on occasion. Usually in response to many-KB jumbogram
7403 sizes being advertised by Squid.
7404 Squid will currently treat these both as an unable-to-resolve domain
7405 even if it would be resolvable without EDNS.
7412 LOC: Config.onoff.res_defnames
7414 Normally the RES_DEFNAMES resolver option is disabled
7415 (see res_init(3)). This prevents caches in a hierarchy
7416 from interpreting single-component hostnames locally. To allow
7417 Squid to handle single-component names, enable this option.
7420 NAME: dns_nameservers
7423 LOC: Config.dns_nameservers
7425 Use this if you want to specify a list of DNS name servers
7426 (IP addresses) to use instead of those given in your
7427 /etc/resolv.conf file.
7428 On Windows platforms, if no value is specified here or in
7429 the /etc/resolv.conf file, the list of DNS name servers are
7430 taken from the Windows registry, both static and dynamic DHCP
7431 configurations are supported.
7433 Example: dns_nameservers 10.0.0.1 192.172.0.4
7438 DEFAULT: @DEFAULT_HOSTS@
7439 LOC: Config.etcHostsPath
7441 Location of the host-local IP name-address associations
7442 database. Most Operating Systems have such a file on different
7444 - Un*X & Linux: /etc/hosts
7445 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
7446 (%SystemRoot% value install default is c:\winnt)
7447 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
7448 (%SystemRoot% value install default is c:\windows)
7449 - Windows 9x/Me: %windir%\hosts
7450 (%windir% value is usually c:\windows)
7451 - Cygwin: /etc/hosts
7453 The file contains newline-separated definitions, in the
7454 form ip_address_in_dotted_form name [name ...] names are
7455 whitespace-separated. Lines beginning with an hash (#)
7456 character are comments.
7458 The file is checked at startup and upon configuration.
7459 If set to 'none', it won't be checked.
7460 If append_domain is used, that domain will be added to
7461 domain-local (i.e. not containing any dot character) host
7467 LOC: Config.appendDomain
7470 Appends local domain name to hostnames without any dots in
7471 them. append_domain must begin with a period.
7473 Be warned there are now Internet names with no dots in
7474 them using only top-domain names, so setting this may
7475 cause some Internet sites to become unavailable.
7478 append_domain .yourdomain.com
7481 NAME: ignore_unknown_nameservers
7483 LOC: Config.onoff.ignore_unknown_nameservers
7485 IFDEF: !USE_DNSHELPER
7487 By default Squid checks that DNS responses are received
7488 from the same IP addresses they are sent to. If they
7489 don't match, Squid ignores the response and writes a warning
7490 message to cache.log. You can allow responses from unknown
7491 nameservers by setting this option to 'off'.
7497 LOC: Config.dns.v4_first
7498 IFDEF: !USE_DNSHELPER
7500 With the IPv6 Internet being as fast or faster than IPv4 Internet
7501 for most networks Squid prefers to contact websites over IPv6.
7503 This option reverses the order of preference to make Squid contact
7504 dual-stack websites over IPv4 first. Squid will still perform both
7505 IPv6 and IPv4 DNS lookups before connecting.
7508 This option will restrict the situations under which IPv6
7509 connectivity is used (and tested). Hiding network problems
7510 which would otherwise be detected and warned about.
7514 COMMENT: (number of entries)
7517 LOC: Config.ipcache.size
7524 LOC: Config.ipcache.low
7531 LOC: Config.ipcache.high
7533 The size, low-, and high-water marks for the IP cache.
7536 NAME: fqdncache_size
7537 COMMENT: (number of entries)
7540 LOC: Config.fqdncache.size
7542 Maximum number of FQDN cache entries.
7547 -----------------------------------------------------------------------------
7554 LOC: Config.onoff.mem_pools
7556 If set, Squid will keep pools of allocated (but unused) memory
7557 available for future use. If memory is a premium on your
7558 system and you believe your malloc library outperforms Squid
7559 routines, disable this.
7562 NAME: memory_pools_limit
7566 LOC: Config.MemPools.limit
7568 Used only with memory_pools on:
7569 memory_pools_limit 50 MB
7571 If set to a non-zero value, Squid will keep at most the specified
7572 limit of allocated (but unused) memory in memory pools. All free()
7573 requests that exceed this limit will be handled by your malloc
7574 library. Squid does not pre-allocate any memory, just safe-keeps
7575 objects that otherwise would be free()d. Thus, it is safe to set
7576 memory_pools_limit to a reasonably high value even if your
7577 configuration will use less memory.
7579 If set to none, Squid will keep all memory it can. That is, there
7580 will be no limit on the total amount of memory used for safe-keeping.
7582 To disable memory allocation optimization, do not set
7583 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
7585 An overhead for maintaining memory pools is not taken into account
7586 when the limit is checked. This overhead is close to four bytes per
7587 object kept. However, pools may actually _save_ memory because of
7588 reduced memory thrashing in your malloc library.
7592 COMMENT: on|off|transparent|truncate|delete
7595 LOC: opt_forwarded_for
7597 If set to "on", Squid will append your client's IP address
7598 in the HTTP requests it forwards. By default it looks like:
7600 X-Forwarded-For: 192.1.2.3
7602 If set to "off", it will appear as
7604 X-Forwarded-For: unknown
7606 If set to "transparent", Squid will not alter the
7607 X-Forwarded-For header in any way.
7609 If set to "delete", Squid will delete the entire
7610 X-Forwarded-For header.
7612 If set to "truncate", Squid will remove all existing
7613 X-Forwarded-For entries, and place the client IP as the sole entry.
7616 NAME: cachemgr_passwd
7617 TYPE: cachemgrpasswd
7619 LOC: Config.passwd_list
7621 Specify passwords for cachemgr operations.
7623 Usage: cachemgr_passwd password action action ...
7625 Some valid actions are (see cache manager menu for a full list):
7665 * Indicates actions which will not be performed without a
7666 valid password, others can be performed if not listed here.
7668 To disable an action, set the password to "disable".
7669 To allow performing an action without a password, set the
7672 Use the keyword "all" to set the same password for all actions.
7675 cachemgr_passwd secret shutdown
7676 cachemgr_passwd lesssssssecret info stats/objects
7677 cachemgr_passwd disable all
7684 LOC: Config.onoff.client_db
7686 If you want to disable collecting per-client statistics,
7687 turn off client_db here.
7690 NAME: refresh_all_ims
7694 LOC: Config.onoff.refresh_all_ims
7696 When you enable this option, squid will always check
7697 the origin server for an update when a client sends an
7698 If-Modified-Since request. Many browsers use IMS
7699 requests when the user requests a reload, and this
7700 ensures those clients receive the latest version.
7702 By default (off), squid may return a Not Modified response
7703 based on the age of the cached version.
7706 NAME: reload_into_ims
7707 IFDEF: USE_HTTP_VIOLATIONS
7711 LOC: Config.onoff.reload_into_ims
7713 When you enable this option, client no-cache or ``reload''
7714 requests will be changed to If-Modified-Since requests.
7715 Doing this VIOLATES the HTTP standard. Enabling this
7716 feature could make you liable for problems which it
7719 see also refresh_pattern for a more selective approach.
7722 NAME: connect_retries
7724 LOC: Config.connect_retries
7727 This sets the maximum number of connection attempts made for each
7728 TCP connection. The connect_retries attempts must all still
7729 complete within the connection timeout period.
7731 The default is not to re-try if the first connection attempt fails.
7732 The (not recommended) maximum is 10 tries.
7734 A warning message will be generated if it is set to a too-high
7735 value and the configured value will be over-ridden.
7737 Note: These re-tries are in addition to forward_max_tries
7738 which limit how many different addresses may be tried to find
7742 NAME: retry_on_error
7744 LOC: Config.retry.onerror
7747 If set to ON Squid will automatically retry requests when
7748 receiving an error response with status 403 (Forbidden),
7749 500 (Internal Error), 501 or 503 (Service not available).
7750 Status 502 and 504 (Gateway errors) are always retried.
7752 This is mainly useful if you are in a complex cache hierarchy to
7753 work around access control errors.
7755 NOTE: This retry will attempt to find another working destination.
7756 Which is different from the server which just failed.
7759 NAME: as_whois_server
7761 LOC: Config.as_whois_server
7762 DEFAULT: whois.ra.net
7764 WHOIS server to query for AS numbers. NOTE: AS numbers are
7765 queried only when Squid starts up, not for every request.
7770 LOC: Config.onoff.offline
7773 Enable this option and Squid will never try to validate cached
7777 NAME: uri_whitespace
7778 TYPE: uri_whitespace
7779 LOC: Config.uri_whitespace
7782 What to do with requests that have whitespace characters in the
7785 strip: The whitespace characters are stripped out of the URL.
7786 This is the behavior recommended by RFC2396.
7787 deny: The request is denied. The user receives an "Invalid
7789 allow: The request is allowed and the URI is not changed. The
7790 whitespace characters remain in the URI. Note the
7791 whitespace is passed to redirector processes if they
7793 encode: The request is allowed and the whitespace characters are
7794 encoded according to RFC1738. This could be considered
7795 a violation of the HTTP/1.1
7796 RFC because proxies are not allowed to rewrite URI's.
7797 chop: The request is allowed and the URI is chopped at the
7798 first whitespace. This might also be considered a
7804 LOC: Config.chroot_dir
7807 Specifies a directory where Squid should do a chroot() while
7808 initializing. This also causes Squid to fully drop root
7809 privileges after initializing. This means, for example, if you
7810 use a HTTP port less than 1024 and try to reconfigure, you may
7811 get an error saying that Squid can not open the port.
7814 NAME: balance_on_multiple_ip
7816 LOC: Config.onoff.balance_on_multiple_ip
7819 Modern IP resolvers in squid sort lookup results by preferred access.
7820 By default squid will use these IP in order and only rotates to
7821 the next listed when the most preffered fails.
7823 Some load balancing servers based on round robin DNS have been
7824 found not to preserve user session state across requests
7825 to different IP addresses.
7827 Enabling this directive Squid rotates IP's per request.
7830 NAME: pipeline_prefetch
7832 LOC: Config.onoff.pipeline_prefetch
7835 To boost the performance of pipelined requests to closer
7836 match that of a non-proxied environment Squid can try to fetch
7837 up to two requests in parallel from a pipeline.
7839 Defaults to off for bandwidth management and access logging
7842 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
7845 NAME: high_response_time_warning
7848 LOC: Config.warnings.high_rptm
7851 If the one-minute median response time exceeds this value,
7852 Squid prints a WARNING with debug level 0 to get the
7853 administrators attention. The value is in milliseconds.
7856 NAME: high_page_fault_warning
7858 LOC: Config.warnings.high_pf
7861 If the one-minute average page fault rate exceeds this
7862 value, Squid prints a WARNING with debug level 0 to get
7863 the administrators attention. The value is in page faults
7867 NAME: high_memory_warning
7869 LOC: Config.warnings.high_memory
7872 If the memory usage (as determined by mallinfo) exceeds
7873 this amount, Squid prints a WARNING with debug level 0 to get
7874 the administrators attention.
7877 NAME: sleep_after_fork
7878 COMMENT: (microseconds)
7880 LOC: Config.sleep_after_fork
7883 When this is set to a non-zero value, the main Squid process
7884 sleeps the specified number of microseconds after a fork()
7885 system call. This sleep may help the situation where your
7886 system reports fork() failures due to lack of (virtual)
7887 memory. Note, however, if you have a lot of child
7888 processes, these sleep delays will add up and your
7889 Squid will not service requests for some amount of time
7890 until all the child processes have been started.
7891 On Windows value less then 1000 (1 milliseconds) are
7895 NAME: windows_ipaddrchangemonitor
7896 IFDEF: _SQUID_MSWIN_
7900 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
7902 On Windows Squid by default will monitor IP address changes and will
7903 reconfigure itself after any detected event. This is very useful for
7904 proxies connected to internet with dial-up interfaces.
7905 In some cases (a Proxy server acting as VPN gateway is one) it could be
7906 desiderable to disable this behaviour setting this to 'off'.
7907 Note: after changing this, Squid service must be restarted.
7912 IFDEF: USE_SQUID_EUI
7914 LOC: Eui::TheConfig.euiLookup
7916 Whether to lookup the EUI or MAC address of a connected client.
7919 NAME: max_filedescriptors max_filedesc
7922 LOC: Config.max_filedescriptors
7924 The maximum number of filedescriptors supported.
7926 The default "0" means Squid inherits the current ulimit setting.
7928 Note: Changing this requires a restart of Squid. Also
7929 not all comm loops supports large values.
7937 Number of main Squid processes or "workers" to fork and maintain.
7938 0: "no daemon" mode, like running "squid -N ..."
7939 1: "no SMP" mode, start one main Squid process daemon (default)
7940 N: start N main Squid process daemons (i.e., SMP mode)
7942 In SMP mode, each worker does nearly all what a single Squid daemon
7943 does (e.g., listen on http_port and forward HTTP requests).
7946 NAME: cpu_affinity_map
7947 TYPE: CpuAffinityMap
7948 LOC: Config.cpuAffinityMap
7951 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
7953 Sets 1:1 mapping between Squid processes and CPU cores. For example,
7955 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
7957 affects processes 1 through 4 only and places them on the first
7958 four even cores, starting with core #1.
7960 CPU cores are numbered starting from 1. Requires support for
7961 sched_getaffinity(2) and sched_setaffinity(2) system calls.
7963 Multiple cpu_affinity_map options are merged.
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