2 # SQUID Web Proxy Cache http://www.squid-cache.org/
3 # ----------------------------------------------------------
5 # Squid is the result of efforts by numerous individuals from
6 # the Internet community; see the CONTRIBUTORS file for full
7 # details. Many organizations have provided support for Squid's
8 # development; see the SPONSORS file for full details. Squid is
9 # Copyrighted (C) 2000 by the Regents of the University of
10 # California; see the COPYRIGHT file for full details. Squid
11 # incorporates software developed and/or copyrighted by other
12 # sources; see the CREDITS file for full details.
14 # This program is free software; you can redistribute it and/or modify
15 # it under the terms of the GNU General Public License as published by
16 # the Free Software Foundation; either version 2 of the License, or
17 # (at your option) any later version.
19 # This program is distributed in the hope that it will be useful,
20 # but WITHOUT ANY WARRANTY; without even the implied warranty of
21 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 # GNU General Public License for more details.
24 # You should have received a copy of the GNU General Public License
25 # along with this program; if not, write to the Free Software
26 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
31 ----------------------------
33 This is the documentation for the Squid configuration file.
34 This documentation can also be found online at:
35 http://www.squid-cache.org/Doc/config/
37 You may wish to look at the Squid home page and wiki for the
38 FAQ and other documentation:
39 http://www.squid-cache.org/
40 http://wiki.squid-cache.org/SquidFaq
41 http://wiki.squid-cache.org/ConfigExamples
43 This documentation shows what the defaults for various directives
44 happen to be. If you don't need to change the default, you should
45 leave the line out of your squid.conf in most cases.
47 In some cases "none" refers to no default setting at all,
48 while in other cases it refers to the value of the option
49 - the comments for that keyword indicate if this is the case.
54 Configuration options can be included using the "include" directive.
55 Include takes a list of files to include. Quoting and wildcards are
60 include /path/to/included/file/squid.acl.config
62 Includes can be nested up to a hard-coded depth of 16 levels.
63 This arbitrary restriction is to prevent recursive include references
64 from causing Squid entering an infinite loop whilst trying to load
68 Conditional configuration
70 If-statements can be used to make configuration directives
74 ... regular configuration directives ...
76 ... regular configuration directives ...]
79 The else part is optional. The keywords "if", "else", and "endif"
80 must be typed on their own lines, as if they were regular
81 configuration directives.
83 NOTE: An else-if condition is not supported.
85 These individual conditions types are supported:
88 Always evaluates to true.
90 Always evaluates to false.
92 Equality comparison of two integer numbers.
97 The following SMP-related preprocessor macros can be used.
99 ${process_name} expands to the current Squid process "name"
100 (e.g., squid1, squid2, or cache1).
102 ${process_number} expands to the current Squid process
103 identifier, which is an integer number (e.g., 1, 2, 3) unique
104 across all Squid processes.
107 # Options Removed in 3.2
108 NAME: ignore_expect_100
111 Remove this line. The HTTP/1.1 feature is now fully supported by default.
114 NAME: dns_v4_fallback
123 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
126 NAME: maximum_single_addr_tries
129 Replaced by connect_retries. The behaviour has changed, please read the documentation before altering.
132 NAME: url_rewrite_concurrency
135 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
138 # Options Removed in 3.1
142 Remove this line. DNS is no longer tested on startup.
145 NAME: extension_methods
148 Remove this line. All valid methods for HTTP are accepted by default.
151 # 2.7 Options Removed/Replaced in 3.2
156 # 2.7 Options Removed/Replaced in 3.1
164 Remove this line. HTTP/1.1 is supported by default.
167 NAME: upgrade_http0.9
170 Remove this line. ICY/1.0 streaming protocol is supported by default.
173 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
176 Alter these entries. Use the qos_flows directive instead.
179 # Options Removed in 3.0
183 Since squid-3.0 replace with request_header_access or reply_header_access
184 depending on whether you wish to match client requests or server replies.
187 NAME: httpd_accel_no_pmtu_disc
190 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
194 OPTIONS FOR AUTHENTICATION
195 -----------------------------------------------------------------------------
204 This is used to define parameters for the various authentication
205 schemes supported by Squid.
207 format: auth_param scheme parameter [setting]
209 The order in which authentication schemes are presented to the client is
210 dependent on the order the scheme first appears in config file. IE
211 has a bug (it's not RFC 2617 compliant) in that it will use the basic
212 scheme if basic is the first entry presented, even if more secure
213 schemes are presented. For now use the order in the recommended
214 settings section below. If other browsers have difficulties (don't
215 recognize the schemes offered even if you are using basic) either
216 put basic first, or disable the other schemes (by commenting out their
219 Once an authentication scheme is fully configured, it can only be
220 shutdown by shutting squid down and restarting. Changes can be made on
221 the fly and activated with a reconfigure. I.E. You can change to a
222 different helper, but not unconfigure the helper completely.
224 Please note that while this directive defines how Squid processes
225 authentication it does not automatically activate authentication.
226 To use authentication you must in addition make use of ACLs based
227 on login name in http_access (proxy_auth, proxy_auth_regex or
228 external with %LOGIN used in the format tag). The browser will be
229 challenged for authentication on the first such acl encountered
230 in http_access processing and will also be re-challenged for new
231 login credentials if the request is being denied by a proxy_auth
234 WARNING: authentication can't be used in a transparently intercepting
235 proxy as the client then thinks it is talking to an origin server and
236 not the proxy. This is a limitation of bending the TCP/IP protocol to
237 transparently intercepting port 80, not a limitation in Squid.
238 Ports flagged 'transparent', 'intercept', or 'tproxy' have
239 authentication disabled.
241 === Parameters for the basic scheme follow. ===
244 Specify the command for the external authenticator. Such a program
245 reads a line containing "username password" and replies "OK" or
246 "ERR" in an endless loop. "ERR" responses may optionally be followed
247 by a error description available as %m in the returned error page.
248 If you use an authenticator, make sure you have 1 acl of type
251 By default, the basic authentication scheme is not used unless a
252 program is specified.
254 If you want to use the traditional NCSA proxy authentication, set
255 this line to something like
257 auth_param basic program @DEFAULT_PREFIX@/libexec/ncsa_auth @DEFAULT_PREFIX@/etc/passwd
260 HTTP uses iso-latin-1 as characterset, while some authentication
261 backends such as LDAP expects UTF-8. If this is set to on Squid will
262 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
263 username & password to the helper.
265 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
266 The maximum number of authenticator processes to spawn. If you start too few
267 Squid will have to wait for them to process a backlog of credential
268 verifications, slowing it down. When password verifications are
269 done via a (slow) network you are likely to need lots of
270 authenticator processes.
272 The startup= and idle= options permit some skew in the exact amount
273 run. A minimum of startup=N will begin during startup and reconfigure.
274 Squid will start more in groups of up to idle=N in an attempt to meet
275 traffic needs and to keep idle=N free above those traffic needs up to
278 The concurrency= option sets the number of concurrent requests the
279 helper can process. The default of 0 is used for helpers who only
280 supports one request at a time. Setting this to a number greater than
281 0 changes the protocol used to include a channel number first on the
282 request/response line, allowing multiple requests to be sent to the
283 same helper in parallell without wating for the response.
284 Must not be set unless it's known the helper supports this.
286 auth_param basic children 20 startup=0 idle=1
289 Specifies the realm name which is to be reported to the
290 client for the basic proxy authentication scheme (part of
291 the text the user will see when prompted their username and
292 password). There is no default.
293 auth_param basic realm Squid proxy-caching web server
295 "credentialsttl" timetolive
296 Specifies how long squid assumes an externally validated
297 username:password pair is valid for - in other words how
298 often the helper program is called for that user. Set this
299 low to force revalidation with short lived passwords. Note
300 setting this high does not impact your susceptibility
301 to replay attacks unless you are using an one-time password
302 system (such as SecureID). If you are using such a system,
303 you will be vulnerable to replay attacks unless you also
304 use the max_user_ip ACL in an http_access rule.
306 "casesensitive" on|off
307 Specifies if usernames are case sensitive. Most user databases are
308 case insensitive allowing the same username to be spelled using both
309 lower and upper case letters, but some are case sensitive. This
310 makes a big difference for user_max_ip ACL processing and similar.
311 auth_param basic casesensitive off
313 === Parameters for the digest scheme follow ===
316 Specify the command for the external authenticator. Such
317 a program reads a line containing "username":"realm" and
318 replies with the appropriate H(A1) value hex encoded or
319 ERR if the user (or his H(A1) hash) does not exists.
320 See rfc 2616 for the definition of H(A1).
321 "ERR" responses may optionally be followed by a error description
322 available as %m in the returned error page.
324 By default, the digest authentication scheme is not used unless a
325 program is specified.
327 If you want to use a digest authenticator, set this line to
330 auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass
333 HTTP uses iso-latin-1 as characterset, while some authentication
334 backends such as LDAP expects UTF-8. If this is set to on Squid will
335 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
336 username & password to the helper.
338 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
339 The maximum number of authenticator processes to spawn (default 5).
340 If you start too few Squid will have to wait for them to
341 process a backlog of H(A1) calculations, slowing it down.
342 When the H(A1) calculations are done via a (slow) network
343 you are likely to need lots of authenticator processes.
345 The startup= and idle= options permit some skew in the exact amount
346 run. A minimum of startup=N will begin during startup and reconfigure.
347 Squid will start more in groups of up to idle=N in an attempt to meet
348 traffic needs and to keep idle=N free above those traffic needs up to
351 The concurrency= option sets the number of concurrent requests the
352 helper can process. The default of 0 is used for helpers who only
353 supports one request at a time. Setting this to a number greater than
354 0 changes the protocol used to include a channel number first on the
355 request/response line, allowing multiple requests to be sent to the
356 same helper in parallell without wating for the response.
357 Must not be set unless it's known the helper supports this.
359 auth_param digest children 20 startup=0 idle=1
362 Specifies the realm name which is to be reported to the
363 client for the digest proxy authentication scheme (part of
364 the text the user will see when prompted their username and
365 password). There is no default.
366 auth_param digest realm Squid proxy-caching web server
368 "nonce_garbage_interval" timeinterval
369 Specifies the interval that nonces that have been issued
370 to client_agent's are checked for validity.
372 "nonce_max_duration" timeinterval
373 Specifies the maximum length of time a given nonce will be
376 "nonce_max_count" number
377 Specifies the maximum number of times a given nonce can be
380 "nonce_strictness" on|off
381 Determines if squid requires strict increment-by-1 behavior
382 for nonce counts, or just incrementing (off - for use when
383 useragents generate nonce counts that occasionally miss 1
384 (ie, 1,2,4,6)). Default off.
386 "check_nonce_count" on|off
387 This directive if set to off can disable the nonce count check
388 completely to work around buggy digest qop implementations in
389 certain mainstream browser versions. Default on to check the
390 nonce count to protect from authentication replay attacks.
392 "post_workaround" on|off
393 This is a workaround to certain buggy browsers who sends
394 an incorrect request digest in POST requests when reusing
395 the same nonce as acquired earlier on a GET request.
397 === NTLM scheme options follow ===
400 Specify the command for the external NTLM authenticator.
401 Such a program reads exchanged NTLMSSP packets with
402 the browser via Squid until authentication is completed.
403 If you use an NTLM authenticator, make sure you have 1 acl
404 of type proxy_auth. By default, the NTLM authenticator_program
407 auth_param ntlm program @DEFAULT_PREFIX@/bin/ntlm_auth
409 "children" numberofchildren [startup=N] [idle=N]
410 The maximum number of authenticator processes to spawn (default 5).
411 If you start too few Squid will have to wait for them to
412 process a backlog of credential verifications, slowing it
413 down. When credential verifications are done via a (slow)
414 network you are likely to need lots of authenticator
417 The startup= and idle= options permit some skew in the exact amount
418 run. A minimum of startup=N will begin during startup and reconfigure.
419 Squid will start more in groups of up to idle=N in an attempt to meet
420 traffic needs and to keep idle=N free above those traffic needs up to
423 auth_param ntlm children 20 startup=0 idle=1
426 If you experience problems with PUT/POST requests when using the
427 Negotiate authentication scheme then you can try setting this to
428 off. This will cause Squid to forcibly close the connection on
429 the initial requests where the browser asks which schemes are
430 supported by the proxy.
432 auth_param ntlm keep_alive on
434 === Options for configuring the NEGOTIATE auth-scheme follow ===
437 Specify the command for the external Negotiate authenticator.
438 This protocol is used in Microsoft Active-Directory enabled setups with
439 the Microsoft Internet Explorer or Mozilla Firefox browsers.
440 Its main purpose is to exchange credentials with the Squid proxy
441 using the Kerberos mechanisms.
442 If you use a Negotiate authenticator, make sure you have at least
443 one acl of type proxy_auth active. By default, the negotiate
444 authenticator_program is not used.
445 The only supported program for this role is the ntlm_auth
446 program distributed as part of Samba, version 4 or later.
448 auth_param negotiate program @DEFAULT_PREFIX@/bin/ntlm_auth --helper-protocol=gss-spnego
450 "children" numberofchildren [startup=N] [idle=N]
451 The maximum number of authenticator processes to spawn (default 5).
452 If you start too few Squid will have to wait for them to
453 process a backlog of credential verifications, slowing it
454 down. When crendential verifications are done via a (slow)
455 network you are likely to need lots of authenticator
458 The startup= and idle= options permit some skew in the exact amount
459 run. A minimum of startup=N will begin during startup and reconfigure.
460 Squid will start more in groups of up to idle=N in an attempt to meet
461 traffic needs and to keep idle=N free above those traffic needs up to
464 auth_param negotiate children 20 startup=0 idle=1
467 If you experience problems with PUT/POST requests when using the
468 Negotiate authentication scheme then you can try setting this to
469 off. This will cause Squid to forcibly close the connection on
470 the initial requests where the browser asks which schemes are
471 supported by the proxy.
473 auth_param negotiate keep_alive on
478 #Recommended minimum configuration per scheme:
479 #auth_param negotiate program <uncomment and complete this line to activate>
480 #auth_param negotiate children 20 startup=0 idle=1
481 #auth_param negotiate keep_alive on
483 #auth_param ntlm program <uncomment and complete this line to activate>
484 #auth_param ntlm children 20 startup=0 idle=1
485 #auth_param ntlm keep_alive on
487 #auth_param digest program <uncomment and complete this line>
488 #auth_param digest children 20 startup=0 idle=1
489 #auth_param digest realm Squid proxy-caching web server
490 #auth_param digest nonce_garbage_interval 5 minutes
491 #auth_param digest nonce_max_duration 30 minutes
492 #auth_param digest nonce_max_count 50
494 #auth_param basic program <uncomment and complete this line>
495 #auth_param basic children 5 startup=5 idle=1
496 #auth_param basic realm Squid proxy-caching web server
497 #auth_param basic credentialsttl 2 hours
500 NAME: authenticate_cache_garbage_interval
503 LOC: Config.authenticateGCInterval
505 The time period between garbage collection across the username cache.
506 This is a tradeoff between memory utilization (long intervals - say
507 2 days) and CPU (short intervals - say 1 minute). Only change if you
511 NAME: authenticate_ttl
514 LOC: Config.authenticateTTL
516 The time a user & their credentials stay in the logged in
517 user cache since their last request. When the garbage
518 interval passes, all user credentials that have passed their
519 TTL are removed from memory.
522 NAME: authenticate_ip_ttl
524 LOC: Config.authenticateIpTTL
527 If you use proxy authentication and the 'max_user_ip' ACL,
528 this directive controls how long Squid remembers the IP
529 addresses associated with each user. Use a small value
530 (e.g., 60 seconds) if your users might change addresses
531 quickly, as is the case with dialups. You might be safe
532 using a larger value (e.g., 2 hours) in a corporate LAN
533 environment with relatively static address assignments.
538 -----------------------------------------------------------------------------
541 NAME: external_acl_type
542 TYPE: externalAclHelper
543 LOC: Config.externalAclHelperList
546 This option defines external acl classes using a helper program
547 to look up the status
549 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
553 ttl=n TTL in seconds for cached results (defaults to 3600
556 TTL for cached negative lookups (default same
559 Maximum number of acl helper processes spawned to service
560 external acl lookups of this type. (default 20)
562 Minimum number of acl helper processes to spawn during
563 startup and reconfigure to service external acl lookups
564 of this type. (default 0)
566 Number of acl helper processes to keep ahead of traffic
567 loads. Squid will spawn this many at once whenever load
568 rises above the capabilities of existing processes.
569 Up to the value of children-max. (default 1)
570 concurrency=n concurrency level per process. Only used with helpers
571 capable of processing more than one query at a time.
572 cache=n limit the result cache size, default is unbounded.
573 grace=n Percentage remaining of TTL where a refresh of a
574 cached entry should be initiated without needing to
575 wait for a new reply. (default is for no grace period)
576 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
577 ipv4 / ipv6 IP protocol used to communicate with this helper.
578 The default is to auto-detect IPv6 and use it when available.
580 FORMAT specifications
582 %LOGIN Authenticated user login name
583 %EXT_USER Username from previous external acl
584 %EXT_LOG Log details from previous external acl
585 %EXT_TAG Tag from previous external acl
586 %IDENT Ident user name
588 %SRCPORT Client source port
591 %PROTO Requested protocol
593 %PATH Requested URL path
594 %METHOD Request method
595 %MYADDR Squid interface address
596 %MYPORT Squid http_port number
597 %PATH Requested URL-path (including query-string if any)
598 %USER_CERT SSL User certificate in PEM format
599 %USER_CERTCHAIN SSL User certificate chain in PEM format
600 %USER_CERT_xx SSL User certificate subject attribute xx
601 %USER_CA_xx SSL User certificate issuer attribute xx
603 %>{Header} HTTP request header "Header"
605 HTTP request header "Hdr" list member "member"
607 HTTP request header list member using ; as
608 list separator. ; can be any non-alphanumeric
611 %<{Header} HTTP reply header "Header"
613 HTTP reply header "Hdr" list member "member"
615 HTTP reply header list member using ; as
616 list separator. ; can be any non-alphanumeric
619 %% The percent sign. Useful for helpers which need
620 an unchanging input format.
622 In addition to the above, any string specified in the referencing
623 acl will also be included in the helper request line, after the
624 specified formats (see the "acl external" directive)
626 The helper receives lines per the above format specification,
627 and returns lines starting with OK or ERR indicating the validity
628 of the request and optionally followed by additional keywords with
631 General result syntax:
633 OK/ERR keyword=value ...
637 user= The users name (login)
638 password= The users password (for login= cache_peer option)
639 message= Message describing the reason. Available as %o
641 tag= Apply a tag to a request (for both ERR and OK results)
642 Only sets a tag, does not alter existing tags.
643 log= String to be logged in access.log. Available as
644 %ea in logformat specifications
646 If protocol=3.0 (the default) then URL escaping is used to protect
647 each value in both requests and responses.
649 If using protocol=2.5 then all values need to be enclosed in quotes
650 if they may contain whitespace, or the whitespace escaped using \.
651 And quotes or \ characters within the keyword value must be \ escaped.
653 When using the concurrency= option the protocol is changed by
654 introducing a query channel tag infront of the request/response.
655 The query channel tag is a number between 0 and concurrency-1.
662 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
663 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
664 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
665 DEFAULT: ssl::certUntrusted ssl_error X509_V_ERR_INVALID_CA X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY X509_V_ERR_CERT_UNTRUSTED
666 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
669 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
670 DEFAULT: localhost src 127.0.0.1/32 ::1
671 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
672 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
674 Defining an Access List
676 Every access list definition must begin with an aclname and acltype,
677 followed by either type-specific arguments or a quoted filename that
680 acl aclname acltype argument ...
681 acl aclname acltype "file" ...
683 When using "file", the file should contain one item per line.
685 By default, regular expressions are CASE-SENSITIVE.
686 To make them case-insensitive, use the -i option. To return case-sensitive
687 use the +i option between patterns, or make a new ACL line without -i.
689 Some acl types require suspending the current request in order
690 to access some external data source.
691 Those which do are marked with the tag [slow], those which
692 don't are marked as [fast].
693 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
694 for further information
696 ***** ACL TYPES AVAILABLE *****
698 acl aclname src ip-address/mask ... # clients IP address [fast]
699 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
700 acl aclname dst ip-address/mask ... # URL host's IP address [slow]
701 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
703 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
704 # The arp ACL requires the special configure option --enable-arp-acl.
705 # Furthermore, the ARP ACL code is not portable to all operating systems.
706 # It works on Linux, Solaris, Windows, FreeBSD, and some
707 # other *BSD variants.
710 # NOTE: Squid can only determine the MAC address for clients that are on
711 # the same subnet. If the client is on a different subnet,
712 # then Squid cannot find out its MAC address.
714 acl aclname srcdomain .foo.com ...
715 # reverse lookup, from client IP [slow]
716 acl aclname dstdomain .foo.com ...
717 # Destination server from URL [fast]
718 acl aclname srcdom_regex [-i] \.foo\.com ...
719 # regex matching client name [slow]
720 acl aclname dstdom_regex [-i] \.foo\.com ...
721 # regex matching server [fast]
723 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
724 # based URL is used and no match is found. The name "none" is used
725 # if the reverse lookup fails.
727 acl aclname src_as number ...
728 acl aclname dst_as number ...
730 # Except for access control, AS numbers can be used for
731 # routing of requests to specific caches. Here's an
732 # example for routing all requests for AS#1241 and only
733 # those to mycache.mydomain.net:
734 # acl asexample dst_as 1241
735 # cache_peer_access mycache.mydomain.net allow asexample
736 # cache_peer_access mycache_mydomain.net deny all
738 acl aclname peername myPeer ...
740 # match against a named cache_peer entry
741 # set unique name= on cache_peer lines for reliable use.
743 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
753 # h1:m1 must be less than h2:m2
755 acl aclname url_regex [-i] ^http:// ...
756 # regex matching on whole URL [fast]
757 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
758 # regex matching on URL login field
759 acl aclname urlpath_regex [-i] \.gif$ ...
760 # regex matching on URL path [fast]
762 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
764 acl aclname localport 3128 ... # TCP port the client connected to [fast]
765 # NP: for interception mode this is usually '80'
767 acl aclname myportname 3128 ... # http(s)_port name [fast]
769 acl aclname proto HTTP FTP ... # request protocol [fast]
771 acl aclname method GET POST ... # HTTP request method [fast]
773 acl aclname http_status 200 301 500- 400-403 ...
774 # status code in reply [fast]
776 acl aclname browser [-i] regexp ...
777 # pattern match on User-Agent header (see also req_header below) [fast]
779 acl aclname referer_regex [-i] regexp ...
780 # pattern match on Referer header [fast]
781 # Referer is highly unreliable, so use with care
783 acl aclname ident username ...
784 acl aclname ident_regex [-i] pattern ...
785 # string match on ident output [slow]
786 # use REQUIRED to accept any non-null ident.
788 acl aclname proxy_auth [-i] username ...
789 acl aclname proxy_auth_regex [-i] pattern ...
790 # perform http authentication challenge to the client and match against
791 # supplied credentials [slow]
793 # takes a list of allowed usernames.
794 # use REQUIRED to accept any valid username.
796 # Will use proxy authentication in forward-proxy scenarios, and plain
797 # http authenticaiton in reverse-proxy scenarios
799 # NOTE: when a Proxy-Authentication header is sent but it is not
800 # needed during ACL checking the username is NOT logged
803 # NOTE: proxy_auth requires a EXTERNAL authentication program
804 # to check username/password combinations (see
805 # auth_param directive).
807 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
808 # as the browser needs to be configured for using a proxy in order
809 # to respond to proxy authentication.
811 acl aclname snmp_community string ...
812 # A community string to limit access to your SNMP Agent [fast]
815 # acl snmppublic snmp_community public
817 acl aclname maxconn number
818 # This will be matched when the client's IP address has
819 # more than <number> TCP connections established. [fast]
820 # NOTE: This only measures direct TCP links so X-Forwarded-For
821 # indirect clients are not counted.
823 acl aclname max_user_ip [-s] number
824 # This will be matched when the user attempts to log in from more
825 # than <number> different ip addresses. The authenticate_ip_ttl
826 # parameter controls the timeout on the ip entries. [fast]
827 # If -s is specified the limit is strict, denying browsing
828 # from any further IP addresses until the ttl has expired. Without
829 # -s Squid will just annoy the user by "randomly" denying requests.
830 # (the counter is reset each time the limit is reached and a
832 # NOTE: in acceleration mode or where there is mesh of child proxies,
833 # clients may appear to come from multiple addresses if they are
834 # going through proxy farms, so a limit of 1 may cause user problems.
836 acl aclname random probability
837 # Pseudo-randomly match requests. Based on the probability given.
838 # Probability may be written as a decimal (0.333), fraction (1/3)
839 # or ratio of matches:non-matches (3:5).
841 acl aclname req_mime_type [-i] mime-type ...
842 # regex match against the mime type of the request generated
843 # by the client. Can be used to detect file upload or some
844 # types HTTP tunneling requests [fast]
845 # NOTE: This does NOT match the reply. You cannot use this
846 # to match the returned file type.
848 acl aclname req_header header-name [-i] any\.regex\.here
849 # regex match against any of the known request headers. May be
850 # thought of as a superset of "browser", "referer" and "mime-type"
853 acl aclname rep_mime_type [-i] mime-type ...
854 # regex match against the mime type of the reply received by
855 # squid. Can be used to detect file download or some
856 # types HTTP tunneling requests. [fast]
857 # NOTE: This has no effect in http_access rules. It only has
858 # effect in rules that affect the reply data stream such as
861 acl aclname rep_header header-name [-i] any\.regex\.here
862 # regex match against any of the known reply headers. May be
863 # thought of as a superset of "browser", "referer" and "mime-type"
866 acl aclname external class_name [arguments...]
867 # external ACL lookup via a helper class defined by the
868 # external_acl_type directive [slow]
870 acl aclname user_cert attribute values...
871 # match against attributes in a user SSL certificate
872 # attribute is one of DN/C/O/CN/L/ST [fast]
874 acl aclname ca_cert attribute values...
875 # match against attributes a users issuing CA SSL certificate
876 # attribute is one of DN/C/O/CN/L/ST [fast]
878 acl aclname ext_user username ...
879 acl aclname ext_user_regex [-i] pattern ...
880 # string match on username returned by external acl helper [slow]
881 # use REQUIRED to accept any non-null user name.
883 acl aclname tag tagvalue ...
884 # string match on tag returned by external acl helper [slow]
886 acl aclname hier_code codename ...
887 # string match against squid hierarchy code(s); [fast]
888 # e.g., DIRECT, PARENT_HIT, NONE, etc.
890 # NOTE: This has no effect in http_access rules. It only has
891 # effect in rules that affect the reply data stream such as
895 acl aclname ssl_error errorname
896 # match against SSL certificate validation error [fast]
898 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
901 # The following can be used as shortcuts for certificate properties:
902 # [ssl::]certHasExpired: the "not after" field is in the past
903 # [ssl::]certNotYetValid: the "not before" field is in the future
904 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
905 # [ssl::]certSelfSigned: The certificate is self signed.
906 # [ssl::]certDomainMismatch: The certificate CN domain does not
907 # match the name the name of the host we are connecting to.
909 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
910 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
911 # predefined ACLs, just like the 'all' ACL.
913 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
914 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
918 acl macaddress arp 09:00:2b:23:45:67
919 acl myexample dst_as 1241
920 acl password proxy_auth REQUIRED
921 acl fileupload req_mime_type -i ^multipart/form-data$
922 acl javascript rep_mime_type -i ^application/x-javascript$
926 # Recommended minimum configuration:
929 # Example rule allowing access from your local networks.
930 # Adapt to list your (internal) IP networks from where browsing
932 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
933 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
934 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
935 acl localnet src fc00::/7 # RFC 4193 local private network range
936 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
938 acl SSL_ports port 443
939 acl Safe_ports port 80 # http
940 acl Safe_ports port 21 # ftp
941 acl Safe_ports port 443 # https
942 acl Safe_ports port 70 # gopher
943 acl Safe_ports port 210 # wais
944 acl Safe_ports port 1025-65535 # unregistered ports
945 acl Safe_ports port 280 # http-mgmt
946 acl Safe_ports port 488 # gss-http
947 acl Safe_ports port 591 # filemaker
948 acl Safe_ports port 777 # multiling http
949 acl CONNECT method CONNECT
953 NAME: follow_x_forwarded_for
955 IFDEF: FOLLOW_X_FORWARDED_FOR
956 LOC: Config.accessList.followXFF
957 DEFAULT_IF_NONE: deny all
959 Allowing or Denying the X-Forwarded-For header to be followed to
960 find the original source of a request.
962 Requests may pass through a chain of several other proxies
963 before reaching us. The X-Forwarded-For header will contain a
964 comma-separated list of the IP addresses in the chain, with the
965 rightmost address being the most recent.
967 If a request reaches us from a source that is allowed by this
968 configuration item, then we consult the X-Forwarded-For header
969 to see where that host received the request from. If the
970 X-Forwarded-For header contains multiple addresses, we continue
971 backtracking until we reach an address for which we are not allowed
972 to follow the X-Forwarded-For header, or until we reach the first
973 address in the list. For the purpose of ACL used in the
974 follow_x_forwarded_for directive the src ACL type always matches
975 the address we are testing and srcdomain matches its rDNS.
977 The end result of this process is an IP address that we will
978 refer to as the indirect client address. This address may
979 be treated as the client address for access control, ICAP, delay
980 pools and logging, depending on the acl_uses_indirect_client,
981 icap_uses_indirect_client, delay_pool_uses_indirect_client,
982 log_uses_indirect_client and tproxy_uses_indirect_client options.
984 This clause only supports fast acl types.
985 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
987 SECURITY CONSIDERATIONS:
989 Any host for which we follow the X-Forwarded-For header
990 can place incorrect information in the header, and Squid
991 will use the incorrect information as if it were the
992 source address of the request. This may enable remote
993 hosts to bypass any access control restrictions that are
994 based on the client's source addresses.
998 acl localhost src 127.0.0.1
999 acl my_other_proxy srcdomain .proxy.example.com
1000 follow_x_forwarded_for allow localhost
1001 follow_x_forwarded_for allow my_other_proxy
1004 NAME: acl_uses_indirect_client
1007 IFDEF: FOLLOW_X_FORWARDED_FOR
1009 LOC: Config.onoff.acl_uses_indirect_client
1011 Controls whether the indirect client address
1012 (see follow_x_forwarded_for) is used instead of the
1013 direct client address in acl matching.
1015 NOTE: maxconn ACL considers direct TCP links and indirect
1016 clients will always have zero. So no match.
1019 NAME: delay_pool_uses_indirect_client
1022 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1024 LOC: Config.onoff.delay_pool_uses_indirect_client
1026 Controls whether the indirect client address
1027 (see follow_x_forwarded_for) is used instead of the
1028 direct client address in delay pools.
1031 NAME: log_uses_indirect_client
1034 IFDEF: FOLLOW_X_FORWARDED_FOR
1036 LOC: Config.onoff.log_uses_indirect_client
1038 Controls whether the indirect client address
1039 (see follow_x_forwarded_for) is used instead of the
1040 direct client address in the access log.
1043 NAME: tproxy_uses_indirect_client
1046 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1048 LOC: Config.onoff.tproxy_uses_indirect_client
1050 Controls whether the indirect client address
1051 (see follow_x_forwarded_for) is used instead of the
1052 direct client address when spoofing the outgoing client.
1054 This has no effect on requests arriving in non-tproxy
1057 SECURITY WARNING: Usage of this option is dangerous
1058 and should not be used trivially. Correct configuration
1059 of follow_x_forewarded_for with a limited set of trusted
1060 sources is required to prevent abuse of your proxy.
1065 LOC: Config.accessList.http
1066 DEFAULT_IF_NONE: deny all
1068 Allowing or Denying access based on defined access lists
1070 Access to the HTTP port:
1071 http_access allow|deny [!]aclname ...
1073 NOTE on default values:
1075 If there are no "access" lines present, the default is to deny
1078 If none of the "access" lines cause a match, the default is the
1079 opposite of the last line in the list. If the last line was
1080 deny, the default is allow. Conversely, if the last line
1081 is allow, the default will be deny. For these reasons, it is a
1082 good idea to have an "deny all" entry at the end of your access
1083 lists to avoid potential confusion.
1085 This clause supports both fast and slow acl types.
1086 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1091 # Recommended minimum Access Permission configuration:
1093 # Only allow cachemgr access from localhost
1094 http_access allow localhost manager
1095 http_access deny manager
1097 # Deny requests to certain unsafe ports
1098 http_access deny !Safe_ports
1100 # Deny CONNECT to other than secure SSL ports
1101 http_access deny CONNECT !SSL_ports
1103 # We strongly recommend the following be uncommented to protect innocent
1104 # web applications running on the proxy server who think the only
1105 # one who can access services on "localhost" is a local user
1106 #http_access deny to_localhost
1109 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1112 # Example rule allowing access from your local networks.
1113 # Adapt localnet in the ACL section to list your (internal) IP networks
1114 # from where browsing should be allowed
1115 http_access allow localnet
1116 http_access allow localhost
1118 # And finally deny all other access to this proxy
1119 http_access deny all
1123 NAME: adapted_http_access http_access2
1125 LOC: Config.accessList.adapted_http
1128 Allowing or Denying access based on defined access lists
1130 Essentially identical to http_access, but runs after redirectors
1131 and ICAP/eCAP adaptation. Allowing access control based on their
1134 If not set then only http_access is used.
1137 NAME: http_reply_access
1139 LOC: Config.accessList.reply
1142 Allow replies to client requests. This is complementary to http_access.
1144 http_reply_access allow|deny [!] aclname ...
1146 NOTE: if there are no access lines present, the default is to allow
1149 If none of the access lines cause a match the opposite of the
1150 last line will apply. Thus it is good practice to end the rules
1151 with an "allow all" or "deny all" entry.
1153 This clause supports both fast and slow acl types.
1154 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1159 LOC: Config.accessList.icp
1160 DEFAULT_IF_NONE: deny all
1162 Allowing or Denying access to the ICP port based on defined
1165 icp_access allow|deny [!]aclname ...
1167 See http_access for details
1169 This clause only supports fast acl types.
1170 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1172 # Allow ICP queries from local networks only
1173 #icp_access allow localnet
1174 #icp_access deny all
1180 LOC: Config.accessList.htcp
1181 DEFAULT_IF_NONE: deny all
1183 Allowing or Denying access to the HTCP port based on defined
1186 htcp_access allow|deny [!]aclname ...
1188 See http_access for details
1190 NOTE: The default if no htcp_access lines are present is to
1191 deny all traffic. This default may cause problems with peers
1192 using the htcp option.
1194 This clause only supports fast acl types.
1195 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1197 # Allow HTCP queries from local networks only
1198 #htcp_access allow localnet
1199 #htcp_access deny all
1202 NAME: htcp_clr_access
1205 LOC: Config.accessList.htcp_clr
1206 DEFAULT_IF_NONE: deny all
1208 Allowing or Denying access to purge content using HTCP based
1209 on defined access lists
1211 htcp_clr_access allow|deny [!]aclname ...
1213 See http_access for details
1215 This clause only supports fast acl types.
1216 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1218 # Allow HTCP CLR requests from trusted peers
1219 acl htcp_clr_peer src 172.16.1.2
1220 htcp_clr_access allow htcp_clr_peer
1225 LOC: Config.accessList.miss
1228 Determins whether network access is permitted when satisfying a request.
1231 to force your neighbors to use you as a sibling instead of
1234 acl localclients src 172.16.0.0/16
1235 miss_access allow localclients
1236 miss_access deny !localclients
1238 This means only your local clients are allowed to fetch relayed/MISS
1239 replies from the network and all other clients can only fetch cached
1243 The default for this setting allows all clients who passed the
1244 http_access rules to relay via this proxy.
1246 This clause only supports fast acl types.
1247 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1250 NAME: ident_lookup_access
1253 DEFAULT_IF_NONE: deny all
1254 LOC: Ident::TheConfig.identLookup
1256 A list of ACL elements which, if matched, cause an ident
1257 (RFC 931) lookup to be performed for this request. For
1258 example, you might choose to always perform ident lookups
1259 for your main multi-user Unix boxes, but not for your Macs
1260 and PCs. By default, ident lookups are not performed for
1263 To enable ident lookups for specific client addresses, you
1264 can follow this example:
1266 acl ident_aware_hosts src 198.168.1.0/24
1267 ident_lookup_access allow ident_aware_hosts
1268 ident_lookup_access deny all
1270 Only src type ACL checks are fully supported. A srcdomain
1271 ACL might work at times, but it will not always provide
1274 This clause only supports fast acl types.
1275 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1278 NAME: reply_body_max_size
1279 COMMENT: size [acl acl...]
1282 LOC: Config.ReplyBodySize
1284 This option specifies the maximum size of a reply body. It can be
1285 used to prevent users from downloading very large files, such as
1286 MP3's and movies. When the reply headers are received, the
1287 reply_body_max_size lines are processed, and the first line where
1288 all (if any) listed ACLs are true is used as the maximum body size
1291 This size is checked twice. First when we get the reply headers,
1292 we check the content-length value. If the content length value exists
1293 and is larger than the allowed size, the request is denied and the
1294 user receives an error message that says "the request or reply
1295 is too large." If there is no content-length, and the reply
1296 size exceeds this limit, the client's connection is just closed
1297 and they will receive a partial reply.
1299 WARNING: downstream caches probably can not detect a partial reply
1300 if there is no content-length header, so they will cache
1301 partial responses and give them out as hits. You should NOT
1302 use this option if you have downstream caches.
1304 WARNING: A maximum size smaller than the size of squid's error messages
1305 will cause an infinite loop and crash squid. Ensure that the smallest
1306 non-zero value you use is greater that the maximum header size plus
1307 the size of your largest error page.
1309 If you set this parameter none (the default), there will be
1312 Configuration Format is:
1313 reply_body_max_size SIZE UNITS [acl ...]
1315 reply_body_max_size 10 MB
1321 -----------------------------------------------------------------------------
1324 NAME: http_port ascii_port
1327 LOC: Config.Sockaddr.http
1329 Usage: port [mode] [options]
1330 hostname:port [mode] [options]
1331 1.2.3.4:port [mode] [options]
1333 The socket addresses where Squid will listen for HTTP client
1334 requests. You may specify multiple socket addresses.
1335 There are three forms: port alone, hostname with port, and
1336 IP address with port. If you specify a hostname or IP
1337 address, Squid binds the socket to that specific
1338 address. Most likely, you do not need to bind to a specific
1339 address, so you can use the port number alone.
1341 If you are running Squid in accelerator mode, you
1342 probably want to listen on port 80 also, or instead.
1344 The -a command line option may be used to specify additional
1345 port(s) where Squid listens for proxy request. Such ports will
1346 be plain proxy ports with no options.
1348 You may specify multiple socket addresses on multiple lines.
1352 intercept Support for IP-Layer interception of
1353 outgoing requests without browser settings.
1354 NP: disables authentication and IPv6 on the port.
1356 tproxy Support Linux TPROXY for spoofing outgoing
1357 connections using the client IP address.
1358 NP: disables authentication and maybe IPv6 on the port.
1360 accel Accelerator / reverse proxy mode
1362 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1363 establish secure connection with the client and with
1364 the server, decrypt HTTPS messages as they pass through
1365 Squid, and treat them as unencrypted HTTP messages,
1366 becoming the man-in-the-middle.
1368 The ssl_bump option is required to fully enable
1369 bumping of CONNECT requests.
1371 Omitting the mode flag causes default forward proxy mode to be used.
1374 Accelerator Mode Options:
1376 defaultsite=domainname
1377 What to use for the Host: header if it is not present
1378 in a request. Determines what site (not origin server)
1379 accelerators should consider the default.
1381 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1383 protocol= Protocol to reconstruct accelerated requests with.
1384 Defaults to http for http_port and https for
1387 vport Virtual host port support. Using the http_port number
1388 instead of the port passed on Host: headers.
1390 vport=NN Virtual host port support. Using the specified port
1391 number instead of the port passed on Host: headers.
1394 Act as if this Squid is the origin server.
1395 This currently means generate new Date: and Expires:
1396 headers on HIT instead of adding Age:.
1398 ignore-cc Ignore request Cache-Control headers.
1400 WARNING: This option violates HTTP specifications if
1401 used in non-accelerator setups.
1403 allow-direct Allow direct forwarding in accelerator mode. Normally
1404 accelerated requests are denied direct forwarding as if
1405 never_direct was used.
1407 WARNING: this option opens accelerator mode to security
1408 vulnerabilities usually only affecting in interception
1409 mode. Make sure to protect forwarding with suitable
1410 http_access rules when using this.
1413 SSL Bump Mode Options:
1414 In addition to these options ssl-bump requires TLS/SSL options.
1416 generate-host-certificates[=<on|off>]
1417 Dynamically create SSL server certificates for the
1418 destination hosts of bumped CONNECT requests.When
1419 enabled, the cert and key options are used to sign
1420 generated certificates. Otherwise generated
1421 certificate will be selfsigned.
1422 If there is a CA certificate lifetime of the generated
1423 certificate equals lifetime of the CA certificate. If
1424 generated certificate is selfsigned lifetime is three
1426 This option is enabled by default when ssl-bump is used.
1427 See the ssl-bump option above for more information.
1429 dynamic_cert_mem_cache_size=SIZE
1430 Approximate total RAM size spent on cached generated
1431 certificates. If set to zero, caching is disabled. The
1432 default value is 4MB.
1436 cert= Path to SSL certificate (PEM format).
1438 key= Path to SSL private key file (PEM format)
1439 if not specified, the certificate file is
1440 assumed to be a combined certificate and
1443 version= The version of SSL/TLS supported
1444 1 automatic (default)
1451 cipher= Colon separated list of supported ciphers.
1452 NOTE: some ciphers such as EDH ciphers depend on
1453 additional settings. If those settings are
1454 omitted the ciphers may be silently ignored
1455 by the OpenSSL library.
1457 options= Various SSL implementation options. The most important
1459 NO_SSLv2 Disallow the use of SSLv2
1460 NO_SSLv3 Disallow the use of SSLv3
1461 NO_TLSv1 Disallow the use of TLSv1.0
1462 NO_TLSv1_1 Disallow the use of TLSv1.1
1463 NO_TLSv1_2 Disallow the use of TLSv1.2
1464 SINGLE_DH_USE Always create a new key when using
1465 temporary/ephemeral DH key exchanges
1466 ALL Enable various bug workarounds
1467 suggested as "harmless" by OpenSSL
1468 Be warned that this reduces SSL/TLS
1469 strength to some attacks.
1470 See OpenSSL SSL_CTX_set_options documentation for a
1471 complete list of options.
1473 clientca= File containing the list of CAs to use when
1474 requesting a client certificate.
1476 cafile= File containing additional CA certificates to
1477 use when verifying client certificates. If unset
1478 clientca will be used.
1480 capath= Directory containing additional CA certificates
1481 and CRL lists to use when verifying client certificates.
1483 crlfile= File of additional CRL lists to use when verifying
1484 the client certificate, in addition to CRLs stored in
1485 the capath. Implies VERIFY_CRL flag below.
1487 dhparams= File containing DH parameters for temporary/ephemeral
1488 DH key exchanges. See OpenSSL documentation for details
1489 on how to create this file.
1490 WARNING: EDH ciphers will be silently disabled if this
1493 sslflags= Various flags modifying the use of SSL:
1495 Don't request client certificates
1496 immediately, but wait until acl processing
1497 requires a certificate (not yet implemented).
1499 Don't use the default CA lists built in
1502 Don't allow for session reuse. Each connection
1503 will result in a new SSL session.
1505 Verify CRL lists when accepting client
1508 Verify CRL lists for all certificates in the
1509 client certificate chain.
1511 sslcontext= SSL session ID context identifier.
1515 connection-auth[=on|off]
1516 use connection-auth=off to tell Squid to prevent
1517 forwarding Microsoft connection oriented authentication
1518 (NTLM, Negotiate and Kerberos)
1520 disable-pmtu-discovery=
1521 Control Path-MTU discovery usage:
1522 off lets OS decide on what to do (default).
1523 transparent disable PMTU discovery when transparent
1525 always disable always PMTU discovery.
1527 In many setups of transparently intercepting proxies
1528 Path-MTU discovery can not work on traffic towards the
1529 clients. This is the case when the intercepting device
1530 does not fully track connections and fails to forward
1531 ICMP must fragment messages to the cache server. If you
1532 have such setup and experience that certain clients
1533 sporadically hang or never complete requests set
1534 disable-pmtu-discovery option to 'transparent'.
1536 name= Specifies a internal name for the port. Defaults to
1537 the port specification (port or addr:port)
1539 tcpkeepalive[=idle,interval,timeout]
1540 Enable TCP keepalive probes of idle connections.
1541 In seconds; idle is the initial time before TCP starts
1542 probing the connection, interval how often to probe, and
1543 timeout the time before giving up.
1545 If you run Squid on a dual-homed machine with an internal
1546 and an external interface we recommend you to specify the
1547 internal address:port in http_port. This way Squid will only be
1548 visible on the internal address.
1552 # Squid normally listens to port 3128
1553 http_port @DEFAULT_HTTP_PORT@
1561 LOC: Config.Sockaddr.https
1563 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1565 The socket address where Squid will listen for client requests made
1566 over TLS or SSL connections. Commonly referred to as HTTPS.
1568 This is most useful for situations where you are running squid in
1569 accelerator mode and you want to do the SSL work at the accelerator level.
1571 You may specify multiple socket addresses on multiple lines,
1572 each with their own SSL certificate and/or options.
1576 accel Accelerator / reverse proxy mode
1578 intercept Support for IP-Layer interception of
1579 outgoing requests without browser settings.
1580 NP: disables authentication and IPv6 on the port.
1582 tproxy Support Linux TPROXY for spoofing outgoing
1583 connections using the client IP address.
1584 NP: disables authentication and maybe IPv6 on the port.
1586 ssl-bump For each intercepted connection allowed by ssl_bump
1587 ACLs, establish a secure connection with the client and with
1588 the server, decrypt HTTPS messages as they pass through
1589 Squid, and treat them as unencrypted HTTP messages,
1590 becoming the man-in-the-middle.
1592 An "ssl_bump server-first" match is required to
1593 fully enable bumping of intercepted SSL connections.
1595 Requires tproxy or intercept.
1597 Omitting the mode flag causes default forward proxy mode to be used.
1600 See http_port for a list of generic options
1605 cert= Path to SSL certificate (PEM format).
1607 key= Path to SSL private key file (PEM format)
1608 if not specified, the certificate file is
1609 assumed to be a combined certificate and
1612 version= The version of SSL/TLS supported
1613 1 automatic (default)
1618 cipher= Colon separated list of supported ciphers.
1620 options= Various SSL engine options. The most important
1622 NO_SSLv2 Disallow the use of SSLv2
1623 NO_SSLv3 Disallow the use of SSLv3
1624 NO_TLSv1 Disallow the use of TLSv1
1625 SINGLE_DH_USE Always create a new key when using
1626 temporary/ephemeral DH key exchanges
1627 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1628 documentation for a complete list of options.
1630 clientca= File containing the list of CAs to use when
1631 requesting a client certificate.
1633 cafile= File containing additional CA certificates to
1634 use when verifying client certificates. If unset
1635 clientca will be used.
1637 capath= Directory containing additional CA certificates
1638 and CRL lists to use when verifying client certificates.
1640 crlfile= File of additional CRL lists to use when verifying
1641 the client certificate, in addition to CRLs stored in
1642 the capath. Implies VERIFY_CRL flag below.
1644 dhparams= File containing DH parameters for temporary/ephemeral
1647 sslflags= Various flags modifying the use of SSL:
1649 Don't request client certificates
1650 immediately, but wait until acl processing
1651 requires a certificate (not yet implemented).
1653 Don't use the default CA lists built in
1656 Don't allow for session reuse. Each connection
1657 will result in a new SSL session.
1659 Verify CRL lists when accepting client
1662 Verify CRL lists for all certificates in the
1663 client certificate chain.
1665 sslcontext= SSL session ID context identifier.
1667 generate-host-certificates[=<on|off>]
1668 Dynamically create SSL server certificates for the
1669 destination hosts of bumped SSL requests.When
1670 enabled, the cert and key options are used to sign
1671 generated certificates. Otherwise generated
1672 certificate will be selfsigned.
1673 If there is CA certificate life time of generated
1674 certificate equals lifetime of CA certificate. If
1675 generated certificate is selfsigned lifetime is three
1677 This option is enabled by default when SslBump is used.
1678 See the sslBump option above for more information.
1680 dynamic_cert_mem_cache_size=SIZE
1681 Approximate total RAM size spent on cached generated
1682 certificates. If set to zero, caching is disabled. The
1683 default value is 4MB.
1685 See http_port for a list of available options.
1688 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1691 LOC: Ip::Qos::TheConfig.tosToServer
1693 Allows you to select a TOS/Diffserv value for packets outgoing
1694 on the server side, based on an ACL.
1696 tcp_outgoing_tos ds-field [!]aclname ...
1698 Example where normal_service_net uses the TOS value 0x00
1699 and good_service_net uses 0x20
1701 acl normal_service_net src 10.0.0.0/24
1702 acl good_service_net src 10.0.1.0/24
1703 tcp_outgoing_tos 0x00 normal_service_net
1704 tcp_outgoing_tos 0x20 good_service_net
1706 TOS/DSCP values really only have local significance - so you should
1707 know what you're specifying. For more information, see RFC2474,
1708 RFC2475, and RFC3260.
1710 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1711 "default" to use whatever default your host has. Note that in
1712 practice often only multiples of 4 is usable as the two rightmost bits
1713 have been redefined for use by ECN (RFC 3168 section 23.1).
1715 Processing proceeds in the order specified, and stops at first fully
1719 NAME: clientside_tos
1722 LOC: Ip::Qos::TheConfig.tosToClient
1724 Allows you to select a TOS/Diffserv value for packets being transmitted
1725 on the client-side, based on an ACL.
1727 clientside_tos ds-field [!]aclname ...
1729 Example where normal_service_net uses the TOS value 0x00
1730 and good_service_net uses 0x20
1732 acl normal_service_net src 10.0.0.0/24
1733 acl good_service_net src 10.0.1.0/24
1734 clientside_tos 0x00 normal_service_net
1735 clientside_tos 0x20 good_service_net
1737 Note: This feature is incompatible with qos_flows. Any TOS values set here
1738 will be overwritten by TOS values in qos_flows.
1741 NAME: tcp_outgoing_mark
1743 IFDEF: SO_MARK&&USE_LIBCAP
1745 LOC: Ip::Qos::TheConfig.nfmarkToServer
1747 Allows you to apply a Netfilter mark value to outgoing packets
1748 on the server side, based on an ACL.
1750 tcp_outgoing_mark mark-value [!]aclname ...
1752 Example where normal_service_net uses the mark value 0x00
1753 and good_service_net uses 0x20
1755 acl normal_service_net src 10.0.0.0/24
1756 acl good_service_net src 10.0.1.0/24
1757 tcp_outgoing_mark 0x00 normal_service_net
1758 tcp_outgoing_mark 0x20 good_service_net
1761 NAME: clientside_mark
1763 IFDEF: SO_MARK&&USE_LIBCAP
1765 LOC: Ip::Qos::TheConfig.nfmarkToClient
1767 Allows you to apply a Netfilter mark value to packets being transmitted
1768 on the client-side, based on an ACL.
1770 clientside_mark mark-value [!]aclname ...
1772 Example where normal_service_net uses the mark value 0x00
1773 and good_service_net uses 0x20
1775 acl normal_service_net src 10.0.0.0/24
1776 acl good_service_net src 10.0.1.0/24
1777 clientside_mark 0x00 normal_service_net
1778 clientside_mark 0x20 good_service_net
1780 Note: This feature is incompatible with qos_flows. Any mark values set here
1781 will be overwritten by mark values in qos_flows.
1788 LOC: Ip::Qos::TheConfig
1790 Allows you to select a TOS/DSCP value to mark outgoing
1791 connections with, based on where the reply was sourced. For
1792 platforms using netfilter, allows you to set a netfilter mark
1793 value instead of, or in addition to, a TOS value.
1795 TOS values really only have local significance - so you should
1796 know what you're specifying. For more information, see RFC2474,
1797 RFC2475, and RFC3260.
1799 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1800 in practice often only multiples of 4 is usable as the two rightmost bits
1801 have been redefined for use by ECN (RFC 3168 section 23.1).
1803 Mark values can be any unsigned 32-bit integer value.
1805 This setting is configured by setting the following values:
1807 tos|mark Whether to set TOS or netfilter mark values
1809 local-hit=0xFF Value to mark local cache hits.
1811 sibling-hit=0xFF Value to mark hits from sibling peers.
1813 parent-hit=0xFF Value to mark hits from parent peers.
1815 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
1816 over the preserve-miss feature (see below), unless
1817 mask is specified, in which case only the bits
1818 specified in the mask are written.
1820 The TOS variant of the following features are only possible on Linux
1821 and require your kernel to be patched with the TOS preserving ZPH
1822 patch, available from http://zph.bratcheda.org
1823 No patch is needed to preserve the netfilter mark, which will work
1824 with all variants of netfilter.
1826 disable-preserve-miss
1827 This option disables the preservation of the TOS or netfilter
1828 mark. By default, the existing TOS or netfilter mark value of
1829 the response coming from the remote server will be retained
1830 and masked with miss-mark.
1831 NOTE: in the case of a netfilter mark, the mark must be set on
1832 the connection (using the CONNMARK target) not on the packet
1836 Allows you to mask certain bits in the TOS or mark value
1837 received from the remote server, before copying the value to
1838 the TOS sent towards clients.
1839 Default for tos: 0xFF (TOS from server is not changed).
1840 Default for mark: 0xFFFFFFFF (mark from server is not changed).
1842 All of these features require the --enable-zph-qos compilation flag
1843 (enabled by default). Netfilter marking also requires the
1844 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
1845 libcap 2.09+ (--with-libcap).
1849 NAME: tcp_outgoing_address
1852 LOC: Config.accessList.outgoing_address
1854 Allows you to map requests to different outgoing IP addresses
1855 based on the username or source address of the user making
1858 tcp_outgoing_address ipaddr [[!]aclname] ...
1861 Forwarding clients with dedicated IPs for certain subnets.
1863 acl normal_service_net src 10.0.0.0/24
1864 acl good_service_net src 10.0.2.0/24
1866 tcp_outgoing_address 2001:db8::c001 good_service_net
1867 tcp_outgoing_address 10.1.0.2 good_service_net
1869 tcp_outgoing_address 2001:db8::beef normal_service_net
1870 tcp_outgoing_address 10.1.0.1 normal_service_net
1872 tcp_outgoing_address 2001:db8::1
1873 tcp_outgoing_address 10.1.0.3
1875 Processing proceeds in the order specified, and stops at first fully
1878 Squid will add an implicit IP version test to each line.
1879 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
1880 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
1883 NOTE: The use of this directive using client dependent ACLs is
1884 incompatible with the use of server side persistent connections. To
1885 ensure correct results it is best to set server_persistent_connections
1886 to off when using this directive in such configurations.
1888 NOTE: The use of this directive to set a local IP on outgoing TCP links
1889 is incompatible with using TPROXY to set client IP out outbound TCP links.
1890 When needing to contact peers use the no-tproxy cache_peer option and the
1891 client_dst_passthru directive re-enable normal forwarding such as this.
1895 NAME: host_verify_strict
1898 LOC: Config.onoff.hostStrictVerify
1900 Regardless of this option setting, when dealing with intercepted
1901 traffic, Squid always verifies that the destination IP address matches
1902 the Host header domain or IP (called 'authority form URL').
1904 This enforcement is performed to satisfy a MUST-level requirement in
1905 RFC 2616 section 14.23: "The Host field value MUST represent the naming
1906 authority of the origin server or gateway given by the original URL".
1909 Squid always responds with an HTTP 409 (Conflict) error
1910 page and logs a security warning if there is no match.
1912 Squid verifies that the destination IP address matches
1913 the Host header for forward-proxy and reverse-proxy traffic
1914 as well. For those traffic types, Squid also enables the
1915 following checks, comparing the corresponding Host header
1916 and Request-URI components:
1918 * The host names (domain or IP) must be identical,
1919 but valueless or missing Host header disables all checks.
1920 For the two host names to match, both must be either IP
1923 * Port numbers must be identical, but if a port is missing
1924 the scheme-default port is assumed.
1927 When set to OFF (the default):
1928 Squid allows suspicious requests to continue but logs a
1929 security warning and blocks caching of the response.
1931 * Forward-proxy traffic is not checked at all.
1933 * Reverse-proxy traffic is not checked at all.
1935 * Intercepted traffic which passes verification is handled
1936 according to client_dst_passthru.
1938 * Intercepted requests which fail verification are sent
1939 to the client original destination instead of DIRECT.
1940 This overrides 'client_dst_passthru off'.
1942 For now suspicious intercepted CONNECT requests are always
1943 responded to with an HTTP 409 (Conflict) error page.
1948 As described in CVE-2009-0801 when the Host: header alone is used
1949 to determine the destination of a request it becomes trivial for
1950 malicious scripts on remote websites to bypass browser same-origin
1951 security policy and sandboxing protections.
1953 The cause of this is that such applets are allowed to perform their
1954 own HTTP stack, in which case the same-origin policy of the browser
1955 sandbox only verifies that the applet tries to contact the same IP
1956 as from where it was loaded at the IP level. The Host: header may
1957 be different from the connected IP and approved origin.
1961 NAME: client_dst_passthru
1964 LOC: Config.onoff.client_dst_passthru
1966 With NAT or TPROXY intercepted traffic Squid may pass the request
1967 directly to the original client destination IP or seek a faster
1968 source using the HTTP Host header.
1970 Using Host to locate alternative servers can provide faster
1971 connectivity with a range of failure recovery options.
1972 But can also lead to connectivity trouble when the client and
1973 server are attempting stateful interactions unaware of the proxy.
1975 This option (on by default) prevents alternative DNS entries being
1976 located to send intercepted traffic DIRECT to an origin server.
1977 The clients original destination IP and port will be used instead.
1979 Regardless of this option setting, when dealing with intercepted
1980 traffic Squid will verify the Host: header and any traffic which
1981 fails Host verification will be treated as if this option were ON.
1983 see host_verify_strict for details on the verification process.
1988 -----------------------------------------------------------------------------
1991 NAME: ssl_unclean_shutdown
1995 LOC: Config.SSL.unclean_shutdown
1997 Some browsers (especially MSIE) bugs out on SSL shutdown
2004 LOC: Config.SSL.ssl_engine
2007 The OpenSSL engine to use. You will need to set this if you
2008 would like to use hardware SSL acceleration for example.
2011 NAME: sslproxy_client_certificate
2014 LOC: Config.ssl_client.cert
2017 Client SSL Certificate to use when proxying https:// URLs
2020 NAME: sslproxy_client_key
2023 LOC: Config.ssl_client.key
2026 Client SSL Key to use when proxying https:// URLs
2029 NAME: sslproxy_version
2032 LOC: Config.ssl_client.version
2035 SSL version level to use when proxying https:// URLs
2037 The versions of SSL/TLS supported:
2039 1 automatic (default)
2047 NAME: sslproxy_options
2050 LOC: Config.ssl_client.options
2053 SSL implementation options to use when proxying https:// URLs
2055 The most important being:
2057 NO_SSLv2 Disallow the use of SSLv2
2058 NO_SSLv3 Disallow the use of SSLv3
2059 NO_TLSv1 Disallow the use of TLSv1.0
2060 NO_TLSv1_1 Disallow the use of TLSv1.1
2061 NO_TLSv1_2 Disallow the use of TLSv1.2
2063 Always create a new key when using temporary/ephemeral
2066 Disable use of RFC5077 session tickets. Some servers
2067 may have problems understanding the TLS extension due
2068 to ambiguous specification in RFC4507.
2069 ALL Enable various bug workarounds suggested as "harmless"
2070 by OpenSSL. Be warned that this may reduce SSL/TLS
2071 strength to some attacks.
2073 See the OpenSSL SSL_CTX_set_options documentation for a
2074 complete list of possible options.
2077 NAME: sslproxy_cipher
2080 LOC: Config.ssl_client.cipher
2083 SSL cipher list to use when proxying https:// URLs
2085 Colon separated list of supported ciphers.
2088 NAME: sslproxy_cafile
2091 LOC: Config.ssl_client.cafile
2094 file containing CA certificates to use when verifying server
2095 certificates while proxying https:// URLs
2098 NAME: sslproxy_capath
2101 LOC: Config.ssl_client.capath
2104 directory containing CA certificates to use when verifying
2105 server certificates while proxying https:// URLs
2110 TYPE: sslproxy_ssl_bump
2111 LOC: Config.accessList.ssl_bump
2114 This option is consulted when a CONNECT request is received on
2115 an http_port (or a new connection is intercepted at an
2116 https_port), provided that port was configured with an ssl-bump
2117 flag. The subsequent data on the connection is either treated as
2118 HTTPS and decrypted OR tunneled at TCP level without decryption,
2119 depending on the first bumping "mode" which ACLs match.
2121 ssl_bump <mode> [!]acl ...
2123 The following bumping modes are supported:
2126 Allow bumping of the connection. Establish a secure connection
2127 with the client first, then connect to the server. This old mode
2128 does not allow Squid to mimic server SSL certificate and does
2129 not work with intercepted SSL connections.
2132 Allow bumping of the connection. Establish a secure connection
2133 with the server first, then establish a secure connection with
2134 the client, using a mimicked server certificate. Works with both
2135 CONNECT requests and intercepted SSL connections.
2138 Become a TCP tunnel without decoding the connection.
2139 Works with both CONNECT requests and intercepted SSL
2140 connections. This is the default behavior when no
2141 ssl_bump option is given or no ssl_bump ACLs match.
2143 By default, no connections are bumped.
2145 The first matching ssl_bump option wins. If no ACLs match, the
2146 connection is not bumped. Unlike most allow/deny ACL lists, ssl_bump
2147 does not have an implicit "negate the last given option" rule. You
2148 must make that rule explicit if you convert old ssl_bump allow/deny
2149 rules that rely on such an implicit rule.
2151 This clause supports both fast and slow acl types.
2152 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2154 See also: http_port ssl-bump, https_port ssl-bump
2157 # Example: Bump all requests except those originating from
2158 # localhost and those going to example.com.
2160 acl broken_sites dstdomain .example.com
2161 ssl_bump none localhost
2162 ssl_bump none broken_sites
2163 ssl_bump server-first all
2166 NAME: sslproxy_flags
2169 LOC: Config.ssl_client.flags
2172 Various flags modifying the use of SSL while proxying https:// URLs:
2173 DONT_VERIFY_PEER Accept certificates that fail verification.
2174 For refined control, see sslproxy_cert_error.
2175 NO_DEFAULT_CA Don't use the default CA list built in
2179 NAME: sslproxy_cert_error
2182 LOC: Config.ssl_client.cert_error
2185 Use this ACL to bypass server certificate validation errors.
2187 For example, the following lines will bypass all validation errors
2188 when talking to servers for example.com. All other
2189 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2191 acl BrokenButTrustedServers dstdomain example.com
2192 sslproxy_cert_error allow BrokenButTrustedServers
2193 sslproxy_cert_error deny all
2195 This clause only supports fast acl types.
2196 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2197 Using slow acl types may result in server crashes
2199 Without this option, all server certificate validation errors
2200 terminate the transaction. Bypassing validation errors is dangerous
2201 because an error usually implies that the server cannot be trusted and
2202 the connection may be insecure.
2204 See also: sslproxy_flags and DONT_VERIFY_PEER.
2206 Default setting: sslproxy_cert_error deny all
2209 NAME: sslproxy_cert_sign
2212 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2213 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2214 POSTSCRIPTUM: signTrusted all
2215 TYPE: sslproxy_cert_sign
2216 LOC: Config.ssl_client.cert_sign
2219 sslproxy_cert_sign <signing algorithm> acl ...
2221 The following certificate signing algorithms are supported:
2223 Sign using the configured CA certificate which is usually
2224 placed in and trusted by end-user browsers. This is the
2225 default for trusted origin server certificates.
2227 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2228 This is the default for untrusted origin server certificates
2229 that are not self-signed (see ssl::certUntrusted).
2231 Sign using a self-signed certificate with the right CN to
2232 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2233 browser. This is the default for self-signed origin server
2234 certificates (see ssl::certSelfSigned).
2236 This clause only supports fast acl types.
2238 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2239 signing algorithm to generate the certificate and ignores all
2240 subsequent sslproxy_cert_sign options (the first match wins). If no
2241 acl(s) match, the default signing algorithm is determined by errors
2242 detected when obtaining and validating the origin server certificate.
2244 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2245 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2246 CONNECT request that carries a domain name. In all other cases (CONNECT
2247 to an IP address or an intercepted SSL connection), Squid cannot detect
2248 the domain mismatch at certificate generation time when
2249 bump-server-first is used.
2252 NAME: sslproxy_cert_adapt
2255 TYPE: sslproxy_cert_adapt
2256 LOC: Config.ssl_client.cert_adapt
2259 sslproxy_cert_adapt <adaptation algorithm> acl ...
2261 The following certificate adaptation algorithms are supported:
2263 Sets the "Not After" property to the "Not After" property of
2264 the CA certificate used to sign generated certificates.
2266 Sets the "Not Before" property to the "Not Before" property of
2267 the CA certificate used to sign generated certificates.
2268 setCommonName or setCommonName{CN}
2269 Sets Subject.CN property to the host name specified as a
2270 CN parameter or, if no explicit CN parameter was specified,
2271 extracted from the CONNECT request. It is a misconfiguration
2272 to use setCommonName without an explicit parameter for
2273 intercepted or tproxied SSL connections.
2275 This clause only supports fast acl types.
2277 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2278 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2279 corresponding adaptation algorithm to generate the certificate and
2280 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2281 group (i.e., the first match wins within each algorithm group). If no
2282 acl(s) match, the default mimicking action takes place.
2284 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2285 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2286 CONNECT request that carries a domain name. In all other cases (CONNECT
2287 to an IP address or an intercepted SSL connection), Squid cannot detect
2288 the domain mismatch at certificate generation time when
2289 bump-server-first is used.
2292 NAME: sslpassword_program
2295 LOC: Config.Program.ssl_password
2298 Specify a program used for entering SSL key passphrases
2299 when using encrypted SSL certificate keys. If not specified
2300 keys must either be unencrypted, or Squid started with the -N
2301 option to allow it to query interactively for the passphrase.
2303 The key file name is given as argument to the program allowing
2304 selection of the right password if you have multiple encrypted
2309 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2310 -----------------------------------------------------------------------------
2313 NAME: sslcrtd_program
2316 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2317 LOC: Ssl::TheConfig.ssl_crtd
2319 Specify the location and options of the executable for ssl_crtd process.
2320 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2321 For more information use:
2322 @DEFAULT_SSL_CRTD@ -h
2325 NAME: sslcrtd_children
2326 TYPE: HelperChildConfig
2328 DEFAULT: 32 startup=5 idle=1
2329 LOC: Ssl::TheConfig.ssl_crtdChildren
2331 The maximum number of processes spawn to service ssl server.
2332 The maximum this may be safely set to is 32.
2334 The startup= and idle= options allow some measure of skew in your
2339 Sets the minimum number of processes to spawn when Squid
2340 starts or reconfigures. When set to zero the first request will
2341 cause spawning of the first child process to handle it.
2343 Starting too few children temporary slows Squid under load while it
2344 tries to spawn enough additional processes to cope with traffic.
2348 Sets a minimum of how many processes Squid is to try and keep available
2349 at all times. When traffic begins to rise above what the existing
2350 processes can handle this many more will be spawned up to the maximum
2351 configured. A minimum setting of 1 is required.
2353 You must have at least one ssl_crtd process.
2356 NAME: sslcrtvalidator_program
2360 LOC: Ssl::TheConfig.ssl_crt_validator
2362 Specify the location and options of the executable for ssl_crt_validator
2366 NAME: sslcrtvalidator_children
2367 TYPE: HelperChildConfig
2369 DEFAULT: 32 startup=5 idle=1
2370 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2372 The maximum number of processes spawn to service ssl server.
2373 The maximum this may be safely set to is 32.
2375 The startup= and idle= options allow some measure of skew in your
2380 Sets the minimum number of processes to spawn when Squid
2381 starts or reconfigures. When set to zero the first request will
2382 cause spawning of the first child process to handle it.
2384 Starting too few children temporary slows Squid under load while it
2385 tries to spawn enough additional processes to cope with traffic.
2389 Sets a minimum of how many processes Squid is to try and keep available
2390 at all times. When traffic begins to rise above what the existing
2391 processes can handle this many more will be spawned up to the maximum
2392 configured. A minimum setting of 1 is required.
2394 You must have at least one ssl_crt_validator process.
2398 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2399 -----------------------------------------------------------------------------
2407 To specify other caches in a hierarchy, use the format:
2409 cache_peer hostname type http-port icp-port [options]
2414 # hostname type port port options
2415 # -------------------- -------- ----- ----- -----------
2416 cache_peer parent.foo.net parent 3128 3130 default
2417 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2418 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2419 cache_peer example.com parent 80 0 default
2420 cache_peer cdn.example.com sibling 3128 0
2422 type: either 'parent', 'sibling', or 'multicast'.
2424 proxy-port: The port number where the peer accept HTTP requests.
2425 For other Squid proxies this is usually 3128
2426 For web servers this is usually 80
2428 icp-port: Used for querying neighbor caches about objects.
2429 Set to 0 if the peer does not support ICP or HTCP.
2430 See ICP and HTCP options below for additional details.
2433 ==== ICP OPTIONS ====
2435 You MUST also set icp_port and icp_access explicitly when using these options.
2436 The defaults will prevent peer traffic using ICP.
2439 no-query Disable ICP queries to this neighbor.
2442 Indicates the named peer is a member of a multicast group.
2443 ICP queries will not be sent directly to the peer, but ICP
2444 replies will be accepted from it.
2446 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2447 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2450 To only send ICP queries to this neighbor infrequently.
2451 This is used to keep the neighbor round trip time updated
2452 and is usually used in conjunction with weighted-round-robin.
2455 ==== HTCP OPTIONS ====
2457 You MUST also set htcp_port and htcp_access explicitly when using these options.
2458 The defaults will prevent peer traffic using HTCP.
2461 htcp Send HTCP, instead of ICP, queries to the neighbor.
2462 You probably also want to set the "icp-port" to 4827
2463 instead of 3130. This directive accepts a comma separated
2464 list of options described below.
2466 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2468 htcp=no-clr Send HTCP to the neighbor but without
2469 sending any CLR requests. This cannot be used with
2472 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2473 This cannot be used with no-clr.
2476 Send HTCP to the neighbor including CLRs but only when
2477 they do not result from PURGE requests.
2480 Forward any HTCP CLR requests this proxy receives to the peer.
2483 ==== PEER SELECTION METHODS ====
2485 The default peer selection method is ICP, with the first responding peer
2486 being used as source. These options can be used for better load balancing.
2489 default This is a parent cache which can be used as a "last-resort"
2490 if a peer cannot be located by any of the peer-selection methods.
2491 If specified more than once, only the first is used.
2493 round-robin Load-Balance parents which should be used in a round-robin
2494 fashion in the absence of any ICP queries.
2495 weight=N can be used to add bias.
2497 weighted-round-robin
2498 Load-Balance parents which should be used in a round-robin
2499 fashion with the frequency of each parent being based on the
2500 round trip time. Closer parents are used more often.
2501 Usually used for background-ping parents.
2502 weight=N can be used to add bias.
2504 carp Load-Balance parents which should be used as a CARP array.
2505 The requests will be distributed among the parents based on the
2506 CARP load balancing hash function based on their weight.
2508 userhash Load-balance parents based on the client proxy_auth or ident username.
2510 sourcehash Load-balance parents based on the client source IP.
2513 To be used only for cache peers of type "multicast".
2514 ALL members of this multicast group have "sibling"
2515 relationship with it, not "parent". This is to a multicast
2516 group when the requested object would be fetched only from
2517 a "parent" cache, anyway. It's useful, e.g., when
2518 configuring a pool of redundant Squid proxies, being
2519 members of the same multicast group.
2522 ==== PEER SELECTION OPTIONS ====
2524 weight=N use to affect the selection of a peer during any weighted
2525 peer-selection mechanisms.
2526 The weight must be an integer; default is 1,
2527 larger weights are favored more.
2528 This option does not affect parent selection if a peering
2529 protocol is not in use.
2531 basetime=N Specify a base amount to be subtracted from round trip
2533 It is subtracted before division by weight in calculating
2534 which parent to fectch from. If the rtt is less than the
2535 base time the rtt is set to a minimal value.
2537 ttl=N Specify a TTL to use when sending multicast ICP queries
2539 Only useful when sending to a multicast group.
2540 Because we don't accept ICP replies from random
2541 hosts, you must configure other group members as
2542 peers with the 'multicast-responder' option.
2544 no-delay To prevent access to this neighbor from influencing the
2547 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2548 enabled) for this host from the specified URL rather
2549 than the Squid default location.
2552 ==== CARP OPTIONS ====
2554 carp-key=key-specification
2555 use a different key than the full URL to hash against the peer.
2556 the key-specification is a comma-separated list of the keywords
2557 scheme, host, port, path, params
2558 Order is not important.
2560 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2562 originserver Causes this parent to be contacted as an origin server.
2563 Meant to be used in accelerator setups when the peer
2567 Set the Host header of requests forwarded to this peer.
2568 Useful in accelerator setups where the server (peer)
2569 expects a certain domain name but clients may request
2570 others. ie example.com or www.example.com
2572 no-digest Disable request of cache digests.
2575 Disables requesting ICMP RTT database (NetDB).
2578 ==== AUTHENTICATION OPTIONS ====
2581 If this is a personal/workgroup proxy and your parent
2582 requires proxy authentication.
2584 Note: The string can include URL escapes (i.e. %20 for
2585 spaces). This also means % must be written as %%.
2588 Send login details received from client to this peer.
2589 Both Proxy- and WWW-Authorization headers are passed
2590 without alteration to the peer.
2591 Authentication is not required by Squid for this to work.
2593 Note: This will pass any form of authentication but
2594 only Basic auth will work through a proxy unless the
2595 connection-auth options are also used.
2597 login=PASS Send login details received from client to this peer.
2598 Authentication is not required by this option.
2600 If there are no client-provided authentication headers
2601 to pass on, but username and password are available
2602 from an external ACL user= and password= result tags
2603 they may be sent instead.
2605 Note: To combine this with proxy_auth both proxies must
2606 share the same user database as HTTP only allows for
2607 a single login (one for proxy, one for origin server).
2608 Also be warned this will expose your users proxy
2609 password to the peer. USE WITH CAUTION
2612 Send the username to the upstream cache, but with a
2613 fixed password. This is meant to be used when the peer
2614 is in another administrative domain, but it is still
2615 needed to identify each user.
2616 The star can optionally be followed by some extra
2617 information which is added to the username. This can
2618 be used to identify this proxy to the peer, similar to
2619 the login=username:password option above.
2622 If this is a personal/workgroup proxy and your parent
2623 requires a secure proxy authentication.
2624 The first principal from the default keytab or defined by
2625 the environment variable KRB5_KTNAME will be used.
2627 WARNING: The connection may transmit requests from multiple
2628 clients. Negotiate often assumes end-to-end authentication
2629 and a single-client. Which is not strictly true here.
2631 login=NEGOTIATE:principal_name
2632 If this is a personal/workgroup proxy and your parent
2633 requires a secure proxy authentication.
2634 The principal principal_name from the default keytab or
2635 defined by the environment variable KRB5_KTNAME will be
2638 WARNING: The connection may transmit requests from multiple
2639 clients. Negotiate often assumes end-to-end authentication
2640 and a single-client. Which is not strictly true here.
2642 connection-auth=on|off
2643 Tell Squid that this peer does or not support Microsoft
2644 connection oriented authentication, and any such
2645 challenges received from there should be ignored.
2646 Default is auto to automatically determine the status
2650 ==== SSL / HTTPS / TLS OPTIONS ====
2652 ssl Encrypt connections to this peer with SSL/TLS.
2654 sslcert=/path/to/ssl/certificate
2655 A client SSL certificate to use when connecting to
2658 sslkey=/path/to/ssl/key
2659 The private SSL key corresponding to sslcert above.
2660 If 'sslkey' is not specified 'sslcert' is assumed to
2661 reference a combined file containing both the
2662 certificate and the key.
2664 sslversion=1|2|3|4|5|6
2665 The SSL version to use when connecting to this peer
2666 1 = automatic (default)
2673 sslcipher=... The list of valid SSL ciphers to use when connecting
2676 ssloptions=... Specify various SSL implementation options:
2678 NO_SSLv2 Disallow the use of SSLv2
2679 NO_SSLv3 Disallow the use of SSLv3
2680 NO_TLSv1 Disallow the use of TLSv1.0
2681 NO_TLSv1_1 Disallow the use of TLSv1.1
2682 NO_TLSv1_2 Disallow the use of TLSv1.2
2684 Always create a new key when using
2685 temporary/ephemeral DH key exchanges
2686 ALL Enable various bug workarounds
2687 suggested as "harmless" by OpenSSL
2688 Be warned that this reduces SSL/TLS
2689 strength to some attacks.
2691 See the OpenSSL SSL_CTX_set_options documentation for a
2694 sslcafile=... A file containing additional CA certificates to use
2695 when verifying the peer certificate.
2697 sslcapath=... A directory containing additional CA certificates to
2698 use when verifying the peer certificate.
2700 sslcrlfile=... A certificate revocation list file to use when
2701 verifying the peer certificate.
2703 sslflags=... Specify various flags modifying the SSL implementation:
2706 Accept certificates even if they fail to
2709 Don't use the default CA list built in
2712 Don't verify the peer certificate
2713 matches the server name
2715 ssldomain= The peer name as advertised in it's certificate.
2716 Used for verifying the correctness of the received peer
2717 certificate. If not specified the peer hostname will be
2721 Enable the "Front-End-Https: On" header needed when
2722 using Squid as a SSL frontend in front of Microsoft OWA.
2723 See MS KB document Q307347 for details on this header.
2724 If set to auto the header will only be added if the
2725 request is forwarded as a https:// URL.
2728 ==== GENERAL OPTIONS ====
2731 A peer-specific connect timeout.
2732 Also see the peer_connect_timeout directive.
2734 connect-fail-limit=N
2735 How many times connecting to a peer must fail before
2736 it is marked as down. Default is 10.
2738 allow-miss Disable Squid's use of only-if-cached when forwarding
2739 requests to siblings. This is primarily useful when
2740 icp_hit_stale is used by the sibling. To extensive use
2741 of this option may result in forwarding loops, and you
2742 should avoid having two-way peerings with this option.
2743 For example to deny peer usage on requests from peer
2744 by denying cache_peer_access if the source is a peer.
2746 max-conn=N Limit the amount of connections Squid may open to this
2749 name=xxx Unique name for the peer.
2750 Required if you have multiple peers on the same host
2751 but different ports.
2752 This name can be used in cache_peer_access and similar
2753 directives to dentify the peer.
2754 Can be used by outgoing access controls through the
2757 no-tproxy Do not use the client-spoof TPROXY support when forwarding
2758 requests to this peer. Use normal address selection instead.
2760 proxy-only objects fetched from the peer will not be stored locally.
2764 NAME: cache_peer_domain cache_host_domain
2769 Use to limit the domains for which a neighbor cache will be
2772 cache_peer_domain cache-host domain [domain ...]
2773 cache_peer_domain cache-host !domain
2775 For example, specifying
2777 cache_peer_domain parent.foo.net .edu
2779 has the effect such that UDP query packets are sent to
2780 'bigserver' only when the requested object exists on a
2781 server in the .edu domain. Prefixing the domainname
2782 with '!' means the cache will be queried for objects
2785 NOTE: * Any number of domains may be given for a cache-host,
2786 either on the same or separate lines.
2787 * When multiple domains are given for a particular
2788 cache-host, the first matched domain is applied.
2789 * Cache hosts with no domain restrictions are queried
2791 * There are no defaults.
2792 * There is also a 'cache_peer_access' tag in the ACL
2796 NAME: cache_peer_access
2801 Similar to 'cache_peer_domain' but provides more flexibility by
2804 cache_peer_access cache-host allow|deny [!]aclname ...
2806 The syntax is identical to 'http_access' and the other lists of
2807 ACL elements. See the comments for 'http_access' below, or
2808 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
2811 NAME: neighbor_type_domain
2812 TYPE: hostdomaintype
2816 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
2818 Modifying the neighbor type for specific domains is now
2819 possible. You can treat some domains differently than the
2820 default neighbor type specified on the 'cache_peer' line.
2821 Normally it should only be necessary to list domains which
2822 should be treated differently because the default neighbor type
2823 applies for hostnames which do not match domains listed here.
2826 cache_peer cache.foo.org parent 3128 3130
2827 neighbor_type_domain cache.foo.org sibling .com .net
2828 neighbor_type_domain cache.foo.org sibling .au .de
2831 NAME: dead_peer_timeout
2835 LOC: Config.Timeout.deadPeer
2837 This controls how long Squid waits to declare a peer cache
2838 as "dead." If there are no ICP replies received in this
2839 amount of time, Squid will declare the peer dead and not
2840 expect to receive any further ICP replies. However, it
2841 continues to send ICP queries, and will mark the peer as
2842 alive upon receipt of the first subsequent ICP reply.
2844 This timeout also affects when Squid expects to receive ICP
2845 replies from peers. If more than 'dead_peer' seconds have
2846 passed since the last ICP reply was received, Squid will not
2847 expect to receive an ICP reply on the next query. Thus, if
2848 your time between requests is greater than this timeout, you
2849 will see a lot of requests sent DIRECT to origin servers
2850 instead of to your parents.
2853 NAME: forward_max_tries
2856 LOC: Config.forward_max_tries
2858 Controls how many different forward paths Squid will try
2859 before giving up. See also forward_timeout.
2861 NOTE: connect_retries (default: none) can make each of these
2862 possible forwarding paths be tried multiple times.
2865 NAME: hierarchy_stoplist
2868 LOC: Config.hierarchy_stoplist
2870 A list of words which, if found in a URL, cause the object to
2871 be handled directly by this cache. In other words, use this
2872 to not query neighbor caches for certain objects. You may
2873 list this option multiple times.
2876 hierarchy_stoplist cgi-bin ?
2878 Note: never_direct overrides this option.
2882 MEMORY CACHE OPTIONS
2883 -----------------------------------------------------------------------------
2890 LOC: Config.memMaxSize
2892 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
2893 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
2894 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
2895 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
2897 'cache_mem' specifies the ideal amount of memory to be used
2899 * In-Transit objects
2901 * Negative-Cached objects
2903 Data for these objects are stored in 4 KB blocks. This
2904 parameter specifies the ideal upper limit on the total size of
2905 4 KB blocks allocated. In-Transit objects take the highest
2908 In-transit objects have priority over the others. When
2909 additional space is needed for incoming data, negative-cached
2910 and hot objects will be released. In other words, the
2911 negative-cached and hot objects will fill up any unused space
2912 not needed for in-transit objects.
2914 If circumstances require, this limit will be exceeded.
2915 Specifically, if your incoming request rate requires more than
2916 'cache_mem' of memory to hold in-transit objects, Squid will
2917 exceed this limit to satisfy the new requests. When the load
2918 decreases, blocks will be freed until the high-water mark is
2919 reached. Thereafter, blocks will be used to store hot
2922 If shared memory caching is enabled, Squid does not use the shared
2923 cache space for in-transit objects, but they still consume as much
2924 local memory as they need. For more details about the shared memory
2925 cache, see memory_cache_shared.
2928 NAME: maximum_object_size_in_memory
2932 LOC: Config.Store.maxInMemObjSize
2934 Objects greater than this size will not be attempted to kept in
2935 the memory cache. This should be set high enough to keep objects
2936 accessed frequently in memory to improve performance whilst low
2937 enough to keep larger objects from hoarding cache_mem.
2940 NAME: memory_cache_shared
2943 LOC: Config.memShared
2945 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
2947 Controls whether the memory cache is shared among SMP workers.
2949 The shared memory cache is meant to occupy cache_mem bytes and replace
2950 the non-shared memory cache, although some entities may still be
2951 cached locally by workers for now (e.g., internal and in-transit
2952 objects may be served from a local memory cache even if shared memory
2953 caching is enabled).
2955 By default, the memory cache is shared if and only if all of the
2956 following conditions are satisfied: Squid runs in SMP mode with
2957 multiple workers, cache_mem is positive, and Squid environment
2958 supports required IPC primitives (e.g., POSIX shared memory segments
2959 and GCC-style atomic operations).
2961 To avoid blocking locks, shared memory uses opportunistic algorithms
2962 that do not guarantee that every cachable entity that could have been
2963 shared among SMP workers will actually be shared.
2965 Currently, entities exceeding 32KB in size cannot be shared.
2968 NAME: memory_cache_mode
2973 Controls which objects to keep in the memory cache (cache_mem)
2975 always Keep most recently fetched objects in memory (default)
2977 disk Only disk cache hits are kept in memory, which means
2978 an object must first be cached on disk and then hit
2979 a second time before cached in memory.
2981 network Only objects fetched from network is kept in memory
2984 NAME: memory_replacement_policy
2986 LOC: Config.memPolicy
2989 The memory replacement policy parameter determines which
2990 objects are purged from memory when memory space is needed.
2992 See cache_replacement_policy for details.
2997 -----------------------------------------------------------------------------
3000 NAME: cache_replacement_policy
3002 LOC: Config.replPolicy
3005 The cache replacement policy parameter determines which
3006 objects are evicted (replaced) when disk space is needed.
3008 lru : Squid's original list based LRU policy
3009 heap GDSF : Greedy-Dual Size Frequency
3010 heap LFUDA: Least Frequently Used with Dynamic Aging
3011 heap LRU : LRU policy implemented using a heap
3013 Applies to any cache_dir lines listed below this.
3015 The LRU policies keeps recently referenced objects.
3017 The heap GDSF policy optimizes object hit rate by keeping smaller
3018 popular objects in cache so it has a better chance of getting a
3019 hit. It achieves a lower byte hit rate than LFUDA though since
3020 it evicts larger (possibly popular) objects.
3022 The heap LFUDA policy keeps popular objects in cache regardless of
3023 their size and thus optimizes byte hit rate at the expense of
3024 hit rate since one large, popular object will prevent many
3025 smaller, slightly less popular objects from being cached.
3027 Both policies utilize a dynamic aging mechanism that prevents
3028 cache pollution that can otherwise occur with frequency-based
3029 replacement policies.
3031 NOTE: if using the LFUDA replacement policy you should increase
3032 the value of maximum_object_size above its default of 4096 KB to
3033 to maximize the potential byte hit rate improvement of LFUDA.
3035 For more information about the GDSF and LFUDA cache replacement
3036 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3037 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3043 LOC: Config.cacheSwap
3047 cache_dir Type Directory-Name Fs-specific-data [options]
3049 You can specify multiple cache_dir lines to spread the
3050 cache among different disk partitions.
3052 Type specifies the kind of storage system to use. Only "ufs"
3053 is built by default. To enable any of the other storage systems
3054 see the --enable-storeio configure option.
3056 'Directory' is a top-level directory where cache swap
3057 files will be stored. If you want to use an entire disk
3058 for caching, this can be the mount-point directory.
3059 The directory must exist and be writable by the Squid
3060 process. Squid will NOT create this directory for you.
3062 In SMP configurations, cache_dir must not precede the workers option
3063 and should use configuration macros or conditionals to give each
3064 worker interested in disk caching a dedicated cache directory.
3068 "ufs" is the old well-known Squid storage format that has always
3071 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3073 'Mbytes' is the amount of disk space (MB) to use under this
3074 directory. The default is 100 MB. Change this to suit your
3075 configuration. Do NOT put the size of your disk drive here.
3076 Instead, if you want Squid to use the entire disk drive,
3077 subtract 20% and use that value.
3079 'L1' is the number of first-level subdirectories which
3080 will be created under the 'Directory'. The default is 16.
3082 'L2' is the number of second-level subdirectories which
3083 will be created under each first-level directory. The default
3086 The aufs store type:
3088 "aufs" uses the same storage format as "ufs", utilizing
3089 POSIX-threads to avoid blocking the main Squid process on
3090 disk-I/O. This was formerly known in Squid as async-io.
3092 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3094 see argument descriptions under ufs above
3096 The diskd store type:
3098 "diskd" uses the same storage format as "ufs", utilizing a
3099 separate process to avoid blocking the main Squid process on
3102 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3104 see argument descriptions under ufs above
3106 Q1 specifies the number of unacknowledged I/O requests when Squid
3107 stops opening new files. If this many messages are in the queues,
3108 Squid won't open new files. Default is 64
3110 Q2 specifies the number of unacknowledged messages when Squid
3111 starts blocking. If this many messages are in the queues,
3112 Squid blocks until it receives some replies. Default is 72
3114 When Q1 < Q2 (the default), the cache directory is optimized
3115 for lower response time at the expense of a decrease in hit
3116 ratio. If Q1 > Q2, the cache directory is optimized for
3117 higher hit ratio at the expense of an increase in response
3120 The rock store type:
3122 cache_dir rock Directory-Name Mbytes <max-size=bytes> [options]
3124 The Rock Store type is a database-style storage. All cached
3125 entries are stored in a "database" file, using fixed-size slots,
3126 one entry per slot. The database size is specified in MB. The
3127 slot size is specified in bytes using the max-size option. See
3128 below for more info on the max-size option.
3130 swap-timeout=msec: Squid will not start writing a miss to or
3131 reading a hit from disk if it estimates that the swap operation
3132 will take more than the specified number of milliseconds. By
3133 default and when set to zero, disables the disk I/O time limit
3134 enforcement. Ignored when using blocking I/O module because
3135 blocking synchronous I/O does not allow Squid to estimate the
3136 expected swap wait time.
3138 max-swap-rate=swaps/sec: Artificially limits disk access using
3139 the specified I/O rate limit. Swap out requests that
3140 would cause the average I/O rate to exceed the limit are
3141 delayed. Individual swap in requests (i.e., hits or reads) are
3142 not delayed, but they do contribute to measured swap rate and
3143 since they are placed in the same FIFO queue as swap out
3144 requests, they may wait longer if max-swap-rate is smaller.
3145 This is necessary on file systems that buffer "too
3146 many" writes and then start blocking Squid and other processes
3147 while committing those writes to disk. Usually used together
3148 with swap-timeout to avoid excessive delays and queue overflows
3149 when disk demand exceeds available disk "bandwidth". By default
3150 and when set to zero, disables the disk I/O rate limit
3151 enforcement. Currently supported by IpcIo module only.
3154 The coss store type:
3156 NP: COSS filesystem in Squid-3 has been deemed too unstable for
3157 production use and has thus been removed from this release.
3158 We hope that it can be made usable again soon.
3160 block-size=n defines the "block size" for COSS cache_dir's.
3161 Squid uses file numbers as block numbers. Since file numbers
3162 are limited to 24 bits, the block size determines the maximum
3163 size of the COSS partition. The default is 512 bytes, which
3164 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
3165 you should not change the coss block size after Squid
3166 has written some objects to the cache_dir.
3168 The coss file store has changed from 2.5. Now it uses a file
3169 called 'stripe' in the directory names in the config - and
3170 this will be created by squid -z.
3174 no-store, no new objects should be stored to this cache_dir
3176 min-size=n, refers to the min object size in bytes this cache_dir
3177 will accept. It's used to restrict a cache_dir to only store
3178 large objects (e.g. aufs) while other storedirs are optimized
3179 for smaller objects (e.g. COSS). Defaults to 0.
3181 max-size=n, refers to the max object size in bytes this cache_dir
3182 supports. It is used to select the cache_dir to store the object.
3183 Note: To make optimal use of the max-size limits you should order
3184 the cache_dir lines with the smallest max-size value first and the
3185 ones with no max-size specification last.
3187 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
3188 which can be changed with the --with-coss-membuf-size=N configure
3192 # Uncomment and adjust the following to add a disk cache directory.
3193 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3197 NAME: store_dir_select_algorithm
3199 LOC: Config.store_dir_select_algorithm
3202 Set this to 'round-robin' as an alternative.
3205 NAME: max_open_disk_fds
3207 LOC: Config.max_open_disk_fds
3210 To avoid having disk as the I/O bottleneck Squid can optionally
3211 bypass the on-disk cache if more than this amount of disk file
3212 descriptors are open.
3214 A value of 0 indicates no limit.
3217 NAME: minimum_object_size
3221 LOC: Config.Store.minObjectSize
3223 Objects smaller than this size will NOT be saved on disk. The
3224 value is specified in kilobytes, and the default is 0 KB, which
3225 means there is no minimum.
3228 NAME: maximum_object_size
3232 LOC: Config.Store.maxObjectSize
3234 Objects larger than this size will NOT be saved on disk. The
3235 value is specified in kilobytes, and the default is 4MB. If
3236 you wish to get a high BYTES hit ratio, you should probably
3237 increase this (one 32 MB object hit counts for 3200 10KB
3238 hits). If you wish to increase speed more than your want to
3239 save bandwidth you should leave this low.
3241 NOTE: if using the LFUDA replacement policy you should increase
3242 this value to maximize the byte hit rate improvement of LFUDA!
3243 See replacement_policy below for a discussion of this policy.
3246 NAME: cache_swap_low
3247 COMMENT: (percent, 0-100)
3250 LOC: Config.Swap.lowWaterMark
3253 NAME: cache_swap_high
3254 COMMENT: (percent, 0-100)
3257 LOC: Config.Swap.highWaterMark
3260 The low- and high-water marks for cache object replacement.
3261 Replacement begins when the swap (disk) usage is above the
3262 low-water mark and attempts to maintain utilization near the
3263 low-water mark. As swap utilization gets close to high-water
3264 mark object eviction becomes more aggressive. If utilization is
3265 close to the low-water mark less replacement is done each time.
3267 Defaults are 90% and 95%. If you have a large cache, 5% could be
3268 hundreds of MB. If this is the case you may wish to set these
3269 numbers closer together.
3274 -----------------------------------------------------------------------------
3284 logformat <name> <format specification>
3286 Defines an access log format.
3288 The <format specification> is a string with embedded % format codes
3290 % format codes all follow the same basic structure where all but
3291 the formatcode is optional. Output strings are automatically escaped
3292 as required according to their context and the output format
3293 modifiers are usually not needed, but can be specified if an explicit
3294 output format is desired.
3296 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3298 " output in quoted string format
3299 [ output in squid text log format as used by log_mime_hdrs
3300 # output in URL quoted format
3305 width minimum and/or maximum field width:
3306 [width_min][.width_max]
3307 When minimum starts with 0, the field is zero-padded.
3308 String values exceeding maximum width are truncated.
3310 {arg} argument such as header name etc
3314 % a literal % character
3315 sn Unique sequence number per log line entry
3316 err_code The ID of an error response served by Squid or
3317 a similar internal error identifier.
3318 err_detail Additional err_code-dependent error information.
3319 note The meta header specified by the argument. Also
3320 logs the adaptation meta headers set by the
3321 adaptation_meta configuration parameter.
3322 If no argument given all meta headers logged.
3324 Connection related format codes:
3326 >a Client source IP address
3328 >p Client source port
3329 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3330 >la Local IP address the client connected to
3331 >lp Local port number the client connected to
3333 la Local listening IP address the client connection was connected to.
3334 lp Local listening port number the client connection was connected to.
3336 <a Server IP address of the last server or peer connection
3337 <A Server FQDN or peer name
3338 <p Server port number of the last server or peer connection
3339 <la Local IP address of the last server or peer connection
3340 <lp Local port number of the last server or peer connection
3342 Time related format codes:
3344 ts Seconds since epoch
3345 tu subsecond time (milliseconds)
3346 tl Local time. Optional strftime format argument
3347 default %d/%b/%Y:%H:%M:%S %z
3348 tg GMT time. Optional strftime format argument
3349 default %d/%b/%Y:%H:%M:%S %z
3350 tr Response time (milliseconds)
3351 dt Total time spent making DNS lookups (milliseconds)
3353 Access Control related format codes:
3355 et Tag returned by external acl
3356 ea Log string returned by external acl
3357 un User name (any available)
3358 ul User name from authentication
3359 ue User name from external acl helper
3360 ui User name from ident
3361 us User name from SSL
3363 HTTP related format codes:
3365 [http::]>h Original request header. Optional header name argument
3366 on the format header[:[separator]element]
3367 [http::]>ha The HTTP request headers after adaptation and redirection.
3368 Optional header name argument as for >h
3369 [http::]<h Reply header. Optional header name argument
3371 [http::]>Hs HTTP status code sent to the client
3372 [http::]<Hs HTTP status code received from the next hop
3373 [http::]<bs Number of HTTP-equivalent message body bytes
3374 received from the next hop, excluding chunked
3375 transfer encoding and control messages.
3376 Generated FTP/Gopher listings are treated as
3378 [http::]mt MIME content type
3379 [http::]rm Request method (GET/POST etc)
3380 [http::]>rm Request method from client
3381 [http::]<rm Request method sent to server or peer
3382 [http::]ru Request URL from client (historic, filtered for logging)
3383 [http::]>ru Request URL from client
3384 [http::]<ru Request URL sent to server or peer
3385 [http::]rp Request URL-Path excluding hostname
3386 [http::]>rp Request URL-Path excluding hostname from client
3387 [http::]<rp Request URL-Path excluding hostname sento to server or peer
3388 [http::]rv Request protocol version
3389 [http::]>rv Request protocol version from client
3390 [http::]<rv Request protocol version sent to server or peer
3391 [http::]<st Sent reply size including HTTP headers
3392 [http::]>st Received request size including HTTP headers. In the
3393 case of chunked requests the chunked encoding metadata
3395 [http::]>sh Received HTTP request headers size
3396 [http::]<sh Sent HTTP reply headers size
3397 [http::]st Request+Reply size including HTTP headers
3398 [http::]<sH Reply high offset sent
3399 [http::]<sS Upstream object size
3400 [http::]<pt Peer response time in milliseconds. The timer starts
3401 when the last request byte is sent to the next hop
3402 and stops when the last response byte is received.
3403 [http::]<tt Total server-side time in milliseconds. The timer
3404 starts with the first connect request (or write I/O)
3405 sent to the first selected peer. The timer stops
3406 with the last I/O with the last peer.
3408 Squid handling related format codes:
3410 Ss Squid request status (TCP_MISS etc)
3411 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3413 SSL-related format codes:
3415 ssl::bump_mode SslBump decision for the transaction:
3417 For CONNECT requests that initiated bumping of
3418 a connection and for any request received on
3419 an already bumped connection, Squid logs the
3420 corresponding SslBump mode ("server-first" or
3421 "client-first"). See the ssl_bump option for
3422 more information about these modes.
3424 A "none" token is logged for requests that
3425 triggered "ssl_bump" ACL evaluation matching
3426 either a "none" rule or no rules at all.
3428 In all other cases, a single dash ("-") is
3431 If ICAP is enabled, the following code becomes available (as
3432 well as ICAP log codes documented with the icap_log option):
3434 icap::tt Total ICAP processing time for the HTTP
3435 transaction. The timer ticks when ICAP
3436 ACLs are checked and when ICAP
3437 transaction is in progress.
3439 If adaptation is enabled the following three codes become available:
3441 adapt::<last_h The header of the last ICAP response or
3442 meta-information from the last eCAP
3443 transaction related to the HTTP transaction.
3444 Like <h, accepts an optional header name
3447 adapt::sum_trs Summed adaptation transaction response
3448 times recorded as a comma-separated list in
3449 the order of transaction start time. Each time
3450 value is recorded as an integer number,
3451 representing response time of one or more
3452 adaptation (ICAP or eCAP) transaction in
3453 milliseconds. When a failed transaction is
3454 being retried or repeated, its time is not
3455 logged individually but added to the
3456 replacement (next) transaction. See also:
3459 adapt::all_trs All adaptation transaction response times.
3460 Same as adaptation_strs but response times of
3461 individual transactions are never added
3462 together. Instead, all transaction response
3463 times are recorded individually.
3465 You can prefix adapt::*_trs format codes with adaptation
3466 service name in curly braces to record response time(s) specific
3467 to that service. For example: %{my_service}adapt::sum_trs
3469 If SSL is enabled, the following formating codes become available:
3471 %ssl::>cert_subject The Subject field of the received client
3472 SSL certificate or a dash ('-') if Squid has
3473 received an invalid/malformed certificate or
3474 no certificate at all. Consider encoding the
3475 logged value because Subject often has spaces.
3477 %ssl::>cert_issuer The Issuer field of the received client
3478 SSL certificate or a dash ('-') if Squid has
3479 received an invalid/malformed certificate or
3480 no certificate at all. Consider encoding the
3481 logged value because Issuer often has spaces.
3483 The default formats available (which do not need re-defining) are:
3485 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3486 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3487 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3488 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3489 logformat useragent %>a [%tl] "%{User-Agent}>h"
3491 NOTE: When the log_mime_hdrs directive is set to ON.
3492 The squid, common and combined formats have a safely encoded copy
3493 of the mime headers appended to each line within a pair of brackets.
3495 NOTE: The common and combined formats are not quite true to the Apache definition.
3496 The logs from Squid contain an extra status and hierarchy code appended.
3500 NAME: access_log cache_access_log
3502 LOC: Config.Log.accesslogs
3503 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3505 These files log client request activities. Has a line every HTTP or
3506 ICP request. The format is:
3507 access_log <module>:<place> [<logformat name> [acl acl ...]]
3508 access_log none [acl acl ...]]
3510 Will log to the specified module:place using the specified format (which
3511 must be defined in a logformat directive) those entries which match
3512 ALL the acl's specified (which must be defined in acl clauses).
3513 If no acl is specified, all requests will be logged to this destination.
3515 ===== Modules Currently available =====
3517 none Do not log any requests matching these ACL.
3518 Do not specify Place or logformat name.
3520 stdio Write each log line to disk immediately at the completion of
3522 Place: the filename and path to be written.
3524 daemon Very similar to stdio. But instead of writing to disk the log
3525 line is passed to a daemon helper for asychronous handling instead.
3526 Place: varies depending on the daemon.
3528 log_file_daemon Place: the file name and path to be written.
3530 syslog To log each request via syslog facility.
3531 Place: The syslog facility and priority level for these entries.
3532 Place Format: facility.priority
3534 where facility could be any of:
3535 authpriv, daemon, local0 ... local7 or user.
3537 And priority could be any of:
3538 err, warning, notice, info, debug.
3540 udp To send each log line as text data to a UDP receiver.
3541 Place: The destination host name or IP and port.
3542 Place Format: //host:port
3544 tcp To send each log line as text data to a TCP receiver.
3545 Place: The destination host name or IP and port.
3546 Place Format: //host:port
3549 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3555 LOC: Config.Log.icaplogs
3558 ICAP log files record ICAP transaction summaries, one line per
3561 The icap_log option format is:
3562 icap_log <filepath> [<logformat name> [acl acl ...]]
3563 icap_log none [acl acl ...]]
3565 Please see access_log option documentation for details. The two
3566 kinds of logs share the overall configuration approach and many
3569 ICAP processing of a single HTTP message or transaction may
3570 require multiple ICAP transactions. In such cases, multiple
3571 ICAP transaction log lines will correspond to a single access
3574 ICAP log uses logformat codes that make sense for an ICAP
3575 transaction. Header-related codes are applied to the HTTP header
3576 embedded in an ICAP server response, with the following caveats:
3577 For REQMOD, there is no HTTP response header unless the ICAP
3578 server performed request satisfaction. For RESPMOD, the HTTP
3579 request header is the header sent to the ICAP server. For
3580 OPTIONS, there are no HTTP headers.
3582 The following format codes are also available for ICAP logs:
3584 icap::<A ICAP server IP address. Similar to <A.
3586 icap::<service_name ICAP service name from the icap_service
3587 option in Squid configuration file.
3589 icap::ru ICAP Request-URI. Similar to ru.
3591 icap::rm ICAP request method (REQMOD, RESPMOD, or
3592 OPTIONS). Similar to existing rm.
3594 icap::>st Bytes sent to the ICAP server (TCP payload
3595 only; i.e., what Squid writes to the socket).
3597 icap::<st Bytes received from the ICAP server (TCP
3598 payload only; i.e., what Squid reads from
3601 icap::<bs Number of message body bytes received from the
3602 ICAP server. ICAP message body, if any, usually
3603 includes encapsulated HTTP message headers and
3604 possibly encapsulated HTTP message body. The
3605 HTTP body part is dechunked before its size is
3608 icap::tr Transaction response time (in
3609 milliseconds). The timer starts when
3610 the ICAP transaction is created and
3611 stops when the transaction is completed.
3614 icap::tio Transaction I/O time (in milliseconds). The
3615 timer starts when the first ICAP request
3616 byte is scheduled for sending. The timers
3617 stops when the last byte of the ICAP response
3620 icap::to Transaction outcome: ICAP_ERR* for all
3621 transaction errors, ICAP_OPT for OPTION
3622 transactions, ICAP_ECHO for 204
3623 responses, ICAP_MOD for message
3624 modification, and ICAP_SAT for request
3625 satisfaction. Similar to Ss.
3627 icap::Hs ICAP response status code. Similar to Hs.
3629 icap::>h ICAP request header(s). Similar to >h.
3631 icap::<h ICAP response header(s). Similar to <h.
3633 The default ICAP log format, which can be used without an explicit
3634 definition, is called icap_squid:
3636 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3638 See also: logformat, log_icap, and %adapt::<last_h
3641 NAME: logfile_daemon
3643 DEFAULT: @DEFAULT_LOGFILED@
3644 LOC: Log::TheConfig.logfile_daemon
3646 Specify the path to the logfile-writing daemon. This daemon is
3647 used to write the access and store logs, if configured.
3649 Squid sends a number of commands to the log daemon:
3650 L<data>\n - logfile data
3655 r<n>\n - set rotate count to <n>
3656 b<n>\n - 1 = buffer output, 0 = don't buffer output
3658 No responses is expected.
3663 LOC: Config.accessList.log
3665 COMMENT: allow|deny acl acl...
3667 This options allows you to control which requests gets logged
3668 to access.log (see access_log directive). Requests denied for
3669 logging will also not be accounted for in performance counters.
3671 This clause only supports fast acl types.
3672 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3678 LOC: Config.accessList.icap
3681 This options allows you to control which requests get logged
3682 to icap.log. See the icap_log directive for ICAP log details.
3685 NAME: cache_store_log
3688 LOC: Config.Log.store
3690 Logs the activities of the storage manager. Shows which
3691 objects are ejected from the cache, and which objects are
3692 saved and for how long.
3693 There are not really utilities to analyze this data, so you can safely
3694 disable it (the default).
3696 Store log uses modular logging outputs. See access_log for the list
3697 of modules supported.
3700 cache_store_log stdio:@DEFAULT_STORE_LOG@
3701 cache_store_log daemon:@DEFAULT_STORE_LOG@
3704 NAME: cache_swap_state cache_swap_log
3706 LOC: Config.Log.swap
3709 Location for the cache "swap.state" file. This index file holds
3710 the metadata of objects saved on disk. It is used to rebuild
3711 the cache during startup. Normally this file resides in each
3712 'cache_dir' directory, but you may specify an alternate
3713 pathname here. Note you must give a full filename, not just
3714 a directory. Since this is the index for the whole object
3715 list you CANNOT periodically rotate it!
3717 If %s can be used in the file name it will be replaced with a
3718 a representation of the cache_dir name where each / is replaced
3719 with '.'. This is needed to allow adding/removing cache_dir
3720 lines when cache_swap_log is being used.
3722 If have more than one 'cache_dir', and %s is not used in the name
3723 these swap logs will have names such as:
3729 The numbered extension (which is added automatically)
3730 corresponds to the order of the 'cache_dir' lines in this
3731 configuration file. If you change the order of the 'cache_dir'
3732 lines in this file, these index files will NOT correspond to
3733 the correct 'cache_dir' entry (unless you manually rename
3734 them). We recommend you do NOT use this option. It is
3735 better to keep these index files in each 'cache_dir' directory.
3738 NAME: logfile_rotate
3741 LOC: Config.Log.rotateNumber
3743 Specifies the number of logfile rotations to make when you
3744 type 'squid -k rotate'. The default is 10, which will rotate
3745 with extensions 0 through 9. Setting logfile_rotate to 0 will
3746 disable the file name rotation, but the logfiles are still closed
3747 and re-opened. This will enable you to rename the logfiles
3748 yourself just before sending the rotate signal.
3750 Note, the 'squid -k rotate' command normally sends a USR1
3751 signal to the running squid process. In certain situations
3752 (e.g. on Linux with Async I/O), USR1 is used for other
3753 purposes, so -k rotate uses another signal. It is best to get
3754 in the habit of using 'squid -k rotate' instead of 'kill -USR1
3757 Note, from Squid-3.1 this option has no effect on the cache.log,
3758 that log can be rotated separately by using debug_options
3761 NAME: emulate_httpd_log
3764 Replace this with an access_log directive using the format 'common' or 'combined'.
3767 NAME: log_ip_on_direct
3770 Remove this option from your config. To log server or peer names use %<A in the log format.
3775 DEFAULT: @DEFAULT_MIME_TABLE@
3776 LOC: Config.mimeTablePathname
3778 Pathname to Squid's MIME table. You shouldn't need to change
3779 this, but the default file contains examples and formatting
3780 information if you do.
3786 LOC: Config.onoff.log_mime_hdrs
3789 The Cache can record both the request and the response MIME
3790 headers for each HTTP transaction. The headers are encoded
3791 safely and will appear as two bracketed fields at the end of
3792 the access log (for either the native or httpd-emulated log
3793 formats). To enable this logging set log_mime_hdrs to 'on'.
3799 Replace this with an access_log directive using the format 'useragent'.
3802 NAME: referer_log referrer_log
3805 Replace this with an access_log directive using the format 'referrer'.
3810 DEFAULT: @DEFAULT_PID_FILE@
3811 LOC: Config.pidFilename
3813 A filename to write the process-id to. To disable, enter "none".
3819 Remove this option from your config. To log FQDN use %>A in the log format.
3822 NAME: client_netmask
3824 LOC: Config.Addrs.client_netmask
3827 A netmask for client addresses in logfiles and cachemgr output.
3828 Change this to protect the privacy of your cache clients.
3829 A netmask of 255.255.255.0 will log all IP's in that range with
3830 the last digit set to '0'.
3836 Use a regular access.log with ACL limiting it to MISS events.
3839 NAME: strip_query_terms
3841 LOC: Config.onoff.strip_query_terms
3844 By default, Squid strips query terms from requested URLs before
3845 logging. This protects your user's privacy.
3852 LOC: Config.onoff.buffered_logs
3854 cache.log log file is written with stdio functions, and as such
3855 it can be buffered or unbuffered. By default it will be unbuffered.
3856 Buffering it can speed up the writing slightly (though you are
3857 unlikely to need to worry unless you run with tons of debugging
3858 enabled in which case performance will suffer badly anyway..).
3861 NAME: netdb_filename
3863 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
3864 LOC: Config.netdbFilename
3867 A filename where Squid stores it's netdb state between restarts.
3868 To disable, enter "none".
3872 OPTIONS FOR TROUBLESHOOTING
3873 -----------------------------------------------------------------------------
3878 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
3879 LOC: Debug::cache_log
3881 Cache logging file. This is where general information about
3882 your cache's behavior goes. You can increase the amount of data
3883 logged to this file and how often its rotated with "debug_options"
3889 LOC: Debug::debugOptions
3891 Logging options are set as section,level where each source file
3892 is assigned a unique section. Lower levels result in less
3893 output, Full debugging (level 9) can result in a very large
3894 log file, so be careful.
3896 The magic word "ALL" sets debugging levels for all sections.
3897 We recommend normally running with "ALL,1".
3899 The rotate=N option can be used to keep more or less of these logs
3900 than would otherwise be kept by logfile_rotate.
3901 For most uses a single log should be enough to monitor current
3902 events affecting Squid.
3907 LOC: Config.coredump_dir
3908 DEFAULT_IF_NONE: none
3910 By default Squid leaves core files in the directory from where
3911 it was started. If you set 'coredump_dir' to a directory
3912 that exists, Squid will chdir() to that directory at startup
3913 and coredump files will be left there.
3917 # Leave coredumps in the first cache dir
3918 coredump_dir @DEFAULT_SWAP_DIR@
3924 OPTIONS FOR FTP GATEWAYING
3925 -----------------------------------------------------------------------------
3931 LOC: Config.Ftp.anon_user
3933 If you want the anonymous login password to be more informative
3934 (and enable the use of picky ftp servers), set this to something
3935 reasonable for your domain, like wwwuser@somewhere.net
3937 The reason why this is domainless by default is the
3938 request can be made on the behalf of a user in any domain,
3939 depending on how the cache is used.
3940 Some ftp server also validate the email address is valid
3941 (for example perl.com).
3947 LOC: Config.Ftp.passive
3949 If your firewall does not allow Squid to use passive
3950 connections, turn off this option.
3952 Use of ftp_epsv_all option requires this to be ON.
3958 LOC: Config.Ftp.epsv_all
3960 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
3962 NATs may be able to put the connection on a "fast path" through the
3963 translator, as the EPRT command will never be used and therefore,
3964 translation of the data portion of the segments will never be needed.
3966 When a client only expects to do two-way FTP transfers this may be
3968 If squid finds that it must do a three-way FTP transfer after issuing
3969 an EPSV ALL command, the FTP session will fail.
3971 If you have any doubts about this option do not use it.
3972 Squid will nicely attempt all other connection methods.
3974 Requires ftp_passive to be ON (default) for any effect.
3980 LOC: Config.Ftp.epsv
3982 FTP Protocol extensions permit the use of a special "EPSV" command.
3984 NATs may be able to put the connection on a "fast path" through the
3985 translator using EPSV, as the EPRT command will never be used
3986 and therefore, translation of the data portion of the segments
3987 will never be needed.
3989 Turning this OFF will prevent EPSV being attempted.
3990 WARNING: Doing so will convert Squid back to the old behavior with all
3991 the related problems with external NAT devices/layers.
3993 Requires ftp_passive to be ON (default) for any effect.
3999 LOC: Config.Ftp.eprt
4001 FTP Protocol extensions permit the use of a special "EPRT" command.
4003 This extension provides a protocol neutral alternative to the
4004 IPv4-only PORT command. When supported it enables active FTP data
4005 channels over IPv6 and efficient NAT handling.
4007 Turning this OFF will prevent EPRT being attempted and will skip
4008 straight to using PORT for IPv4 servers.
4010 Some devices are known to not handle this extension correctly and
4011 may result in crashes. Devices which suport EPRT enough to fail
4012 cleanly will result in Squid attempting PORT anyway. This directive
4013 should only be disabled when EPRT results in device failures.
4015 WARNING: Doing so will convert Squid back to the old behavior with all
4016 the related problems with external NAT devices/layers and IPv4-only FTP.
4019 NAME: ftp_sanitycheck
4022 LOC: Config.Ftp.sanitycheck
4024 For security and data integrity reasons Squid by default performs
4025 sanity checks of the addresses of FTP data connections ensure the
4026 data connection is to the requested server. If you need to allow
4027 FTP connections to servers using another IP address for the data
4028 connection turn this off.
4031 NAME: ftp_telnet_protocol
4034 LOC: Config.Ftp.telnet
4036 The FTP protocol is officially defined to use the telnet protocol
4037 as transport channel for the control connection. However, many
4038 implementations are broken and does not respect this aspect of
4041 If you have trouble accessing files with ASCII code 255 in the
4042 path or similar problems involving this ASCII code you can
4043 try setting this directive to off. If that helps, report to the
4044 operator of the FTP server in question that their FTP server
4045 is broken and does not follow the FTP standard.
4049 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4050 -----------------------------------------------------------------------------
4055 DEFAULT: @DEFAULT_DISKD@
4056 LOC: Config.Program.diskd
4058 Specify the location of the diskd executable.
4059 Note this is only useful if you have compiled in
4060 diskd as one of the store io modules.
4063 NAME: unlinkd_program
4066 DEFAULT: @DEFAULT_UNLINKD@
4067 LOC: Config.Program.unlinkd
4069 Specify the location of the executable for file deletion process.
4072 NAME: pinger_program
4074 DEFAULT: @DEFAULT_PINGER@
4075 LOC: Config.pinger.program
4078 Specify the location of the executable for the pinger process.
4084 LOC: Config.pinger.enable
4087 Control whether the pinger is active at run-time.
4088 Enables turning ICMP pinger on and off with a simple
4089 squid -k reconfigure.
4094 OPTIONS FOR URL REWRITING
4095 -----------------------------------------------------------------------------
4098 NAME: url_rewrite_program redirect_program
4100 LOC: Config.Program.redirect
4103 Specify the location of the executable URL rewriter to use.
4104 Since they can perform almost any function there isn't one included.
4106 For each requested URL, the rewriter will receive on line with the format
4108 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
4110 In the future, the rewriter interface will be extended with
4111 key=value pairs ("kvpairs" shown above). Rewriter programs
4112 should be prepared to receive and possibly ignore additional
4113 whitespace-separated tokens on each input line.
4115 And the rewriter may return a rewritten URL. The other components of
4116 the request line does not need to be returned (ignored if they are).
4118 The rewriter can also indicate that a client-side redirect should
4119 be performed to the new URL. This is done by prefixing the returned
4120 URL with "301:" (moved permanently) or 302: (moved temporarily), etc.
4122 By default, a URL rewriter is not used.
4125 NAME: url_rewrite_children redirect_children
4126 TYPE: HelperChildConfig
4127 DEFAULT: 20 startup=0 idle=1 concurrency=0
4128 LOC: Config.redirectChildren
4130 The maximum number of redirector processes to spawn. If you limit
4131 it too few Squid will have to wait for them to process a backlog of
4132 URLs, slowing it down. If you allow too many they will use RAM
4133 and other system resources noticably.
4135 The startup= and idle= options allow some measure of skew in your
4140 Sets a minimum of how many processes are to be spawned when Squid
4141 starts or reconfigures. When set to zero the first request will
4142 cause spawning of the first child process to handle it.
4144 Starting too few will cause an initial slowdown in traffic as Squid
4145 attempts to simultaneously spawn enough processes to cope.
4149 Sets a minimum of how many processes Squid is to try and keep available
4150 at all times. When traffic begins to rise above what the existing
4151 processes can handle this many more will be spawned up to the maximum
4152 configured. A minimum setting of 1 is required.
4156 The number of requests each redirector helper can handle in
4157 parallel. Defaults to 0 which indicates the redirector
4158 is a old-style single threaded redirector.
4160 When this directive is set to a value >= 1 then the protocol
4161 used to communicate with the helper is modified to include
4162 a request ID in front of the request/response. The request
4163 ID from the request must be echoed back with the response
4167 NAME: url_rewrite_host_header redirect_rewrites_host_header
4170 LOC: Config.onoff.redir_rewrites_host
4172 To preserve same-origin security policies in browsers and
4173 prevent Host: header forgery by redirectors Squid rewrites
4174 any Host: header in redirected requests.
4176 If you are running an accelerator this may not be a wanted
4177 effect of a redirector. This directive enables you disable
4178 Host: alteration in reverse-proxy traffic.
4180 WARNING: Entries are cached on the result of the URL rewriting
4181 process, so be careful if you have domain-virtual hosts.
4183 WARNING: Squid and other software verifies the URL and Host
4184 are matching, so be careful not to relay through other proxies
4185 or inspecting firewalls with this disabled.
4188 NAME: url_rewrite_access redirector_access
4191 LOC: Config.accessList.redirector
4193 If defined, this access list specifies which requests are
4194 sent to the redirector processes. By default all requests
4197 This clause supports both fast and slow acl types.
4198 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4201 NAME: url_rewrite_bypass redirector_bypass
4203 LOC: Config.onoff.redirector_bypass
4206 When this is 'on', a request will not go through the
4207 redirector if all redirectors are busy. If this is 'off'
4208 and the redirector queue grows too large, Squid will exit
4209 with a FATAL error and ask you to increase the number of
4210 redirectors. You should only enable this if the redirectors
4211 are not critical to your caching system. If you use
4212 redirectors for access control, and you enable this option,
4213 users may have access to pages they should not
4214 be allowed to request.
4218 OPTIONS FOR TUNING THE CACHE
4219 -----------------------------------------------------------------------------
4222 NAME: cache no_cache
4225 LOC: Config.accessList.noCache
4227 A list of ACL elements which, if matched and denied, cause the request to
4228 not be satisfied from the cache and the reply to not be cached.
4229 In other words, use this to force certain objects to never be cached.
4231 You must use the words 'allow' or 'deny' to indicate whether items
4232 matching the ACL should be allowed or denied into the cache.
4234 Default is to allow all to be cached.
4236 This clause supports both fast and slow acl types.
4237 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4243 LOC: Config.maxStale
4246 This option puts an upper limit on how stale content Squid
4247 will serve from the cache if cache validation fails.
4248 Can be overriden by the refresh_pattern max-stale option.
4251 NAME: refresh_pattern
4252 TYPE: refreshpattern
4256 usage: refresh_pattern [-i] regex min percent max [options]
4258 By default, regular expressions are CASE-SENSITIVE. To make
4259 them case-insensitive, use the -i option.
4261 'Min' is the time (in minutes) an object without an explicit
4262 expiry time should be considered fresh. The recommended
4263 value is 0, any higher values may cause dynamic applications
4264 to be erroneously cached unless the application designer
4265 has taken the appropriate actions.
4267 'Percent' is a percentage of the objects age (time since last
4268 modification age) an object without explicit expiry time
4269 will be considered fresh.
4271 'Max' is an upper limit on how long objects without an explicit
4272 expiry time will be considered fresh.
4274 options: override-expire
4279 ignore-must-revalidate
4286 override-expire enforces min age even if the server
4287 sent an explicit expiry time (e.g., with the
4288 Expires: header or Cache-Control: max-age). Doing this
4289 VIOLATES the HTTP standard. Enabling this feature
4290 could make you liable for problems which it causes.
4292 Note: override-expire does not enforce staleness - it only extends
4293 freshness / min. If the server returns a Expires time which
4294 is longer than your max time, Squid will still consider
4295 the object fresh for that period of time.
4297 override-lastmod enforces min age even on objects
4298 that were modified recently.
4300 reload-into-ims changes client no-cache or ``reload''
4301 to If-Modified-Since requests. Doing this VIOLATES the
4302 HTTP standard. Enabling this feature could make you
4303 liable for problems which it causes.
4305 ignore-reload ignores a client no-cache or ``reload''
4306 header. Doing this VIOLATES the HTTP standard. Enabling
4307 this feature could make you liable for problems which
4310 ignore-no-store ignores any ``Cache-control: no-store''
4311 headers received from a server. Doing this VIOLATES
4312 the HTTP standard. Enabling this feature could make you
4313 liable for problems which it causes.
4315 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
4316 headers received from a server. Doing this VIOLATES
4317 the HTTP standard. Enabling this feature could make you
4318 liable for problems which it causes.
4320 ignore-private ignores any ``Cache-control: private''
4321 headers received from a server. Doing this VIOLATES
4322 the HTTP standard. Enabling this feature could make you
4323 liable for problems which it causes.
4325 ignore-auth caches responses to requests with authorization,
4326 as if the originserver had sent ``Cache-control: public''
4327 in the response header. Doing this VIOLATES the HTTP standard.
4328 Enabling this feature could make you liable for problems which
4331 refresh-ims causes squid to contact the origin server
4332 when a client issues an If-Modified-Since request. This
4333 ensures that the client will receive an updated version
4334 if one is available.
4336 store-stale stores responses even if they don't have explicit
4337 freshness or a validator (i.e., Last-Modified or an ETag)
4338 present, or if they're already stale. By default, Squid will
4339 not cache such responses because they usually can't be
4340 reused. Note that such responses will be stale by default.
4342 max-stale=NN provide a maximum staleness factor. Squid won't
4343 serve objects more stale than this even if it failed to
4344 validate the object. Default: use the max_stale global limit.
4346 Basically a cached object is:
4348 FRESH if expires < now, else STALE
4350 FRESH if lm-factor < percent, else STALE
4354 The refresh_pattern lines are checked in the order listed here.
4355 The first entry which matches is used. If none of the entries
4356 match the default will be used.
4358 Note, you must uncomment all the default lines if you want
4359 to change one. The default setting is only active if none is
4364 # Add any of your own refresh_pattern entries above these.
4365 refresh_pattern ^ftp: 1440 20% 10080
4366 refresh_pattern ^gopher: 1440 0% 1440
4367 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
4368 refresh_pattern . 0 20% 4320
4372 NAME: quick_abort_min
4376 LOC: Config.quickAbort.min
4379 NAME: quick_abort_max
4383 LOC: Config.quickAbort.max
4386 NAME: quick_abort_pct
4390 LOC: Config.quickAbort.pct
4392 The cache by default continues downloading aborted requests
4393 which are almost completed (less than 16 KB remaining). This
4394 may be undesirable on slow (e.g. SLIP) links and/or very busy
4395 caches. Impatient users may tie up file descriptors and
4396 bandwidth by repeatedly requesting and immediately aborting
4399 When the user aborts a request, Squid will check the
4400 quick_abort values to the amount of data transfered until
4403 If the transfer has less than 'quick_abort_min' KB remaining,
4404 it will finish the retrieval.
4406 If the transfer has more than 'quick_abort_max' KB remaining,
4407 it will abort the retrieval.
4409 If more than 'quick_abort_pct' of the transfer has completed,
4410 it will finish the retrieval.
4412 If you do not want any retrieval to continue after the client
4413 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
4416 If you want retrievals to always continue if they are being
4417 cached set 'quick_abort_min' to '-1 KB'.
4420 NAME: read_ahead_gap
4421 COMMENT: buffer-size
4423 LOC: Config.readAheadGap
4426 The amount of data the cache will buffer ahead of what has been
4427 sent to the client when retrieving an object from another server.
4431 IFDEF: USE_HTTP_VIOLATIONS
4434 LOC: Config.negativeTtl
4437 Set the Default Time-to-Live (TTL) for failed requests.
4438 Certain types of failures (such as "connection refused" and
4439 "404 Not Found") are able to be negatively-cached for a short time.
4440 Modern web servers should provide Expires: header, however if they
4441 do not this can provide a minimum TTL.
4442 The default is not to cache errors with unknown expiry details.
4444 Note that this is different from negative caching of DNS lookups.
4446 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4447 this feature could make you liable for problems which it
4451 NAME: positive_dns_ttl
4454 LOC: Config.positiveDnsTtl
4457 Upper limit on how long Squid will cache positive DNS responses.
4458 Default is 6 hours (360 minutes). This directive must be set
4459 larger than negative_dns_ttl.
4462 NAME: negative_dns_ttl
4465 LOC: Config.negativeDnsTtl
4468 Time-to-Live (TTL) for negative caching of failed DNS lookups.
4469 This also sets the lower cache limit on positive lookups.
4470 Minimum value is 1 second, and it is not recommendable to go
4471 much below 10 seconds.
4474 NAME: range_offset_limit
4475 COMMENT: size [acl acl...]
4477 LOC: Config.rangeOffsetLimit
4480 usage: (size) [units] [[!]aclname]
4482 Sets an upper limit on how far (number of bytes) into the file
4483 a Range request may be to cause Squid to prefetch the whole file.
4484 If beyond this limit, Squid forwards the Range request as it is and
4485 the result is NOT cached.
4487 This is to stop a far ahead range request (lets say start at 17MB)
4488 from making Squid fetch the whole object up to that point before
4489 sending anything to the client.
4491 Multiple range_offset_limit lines may be specified, and they will
4492 be searched from top to bottom on each request until a match is found.
4493 The first match found will be used. If no line matches a request, the
4494 default limit of 0 bytes will be used.
4496 'size' is the limit specified as a number of units.
4498 'units' specifies whether to use bytes, KB, MB, etc.
4499 If no units are specified bytes are assumed.
4501 A size of 0 causes Squid to never fetch more than the
4502 client requested. (default)
4504 A size of 'none' causes Squid to always fetch the object from the
4505 beginning so it may cache the result. (2.0 style)
4507 'aclname' is the name of a defined ACL.
4509 NP: Using 'none' as the byte value here will override any quick_abort settings
4510 that may otherwise apply to the range request. The range request will
4511 be fully fetched from start to finish regardless of the client
4512 actions. This affects bandwidth usage.
4515 NAME: minimum_expiry_time
4518 LOC: Config.minimum_expiry_time
4521 The minimum caching time according to (Expires - Date)
4522 Headers Squid honors if the object can't be revalidated
4523 defaults to 60 seconds. In reverse proxy environments it
4524 might be desirable to honor shorter object lifetimes. It
4525 is most likely better to make your server return a
4526 meaningful Last-Modified header however. In ESI environments
4527 where page fragments often have short lifetimes, this will
4528 often be best set to 0.
4531 NAME: store_avg_object_size
4535 LOC: Config.Store.avgObjectSize
4537 Average object size, used to estimate number of objects your
4538 cache can hold. The default is 13 KB.
4541 NAME: store_objects_per_bucket
4544 LOC: Config.Store.objectsPerBucket
4546 Target number of objects per bucket in the store hash table.
4547 Lowering this value increases the total number of buckets and
4548 also the storage maintenance rate. The default is 20.
4553 -----------------------------------------------------------------------------
4556 NAME: request_header_max_size
4560 LOC: Config.maxRequestHeaderSize
4562 This specifies the maximum size for HTTP headers in a request.
4563 Request headers are usually relatively small (about 512 bytes).
4564 Placing a limit on the request header size will catch certain
4565 bugs (for example with persistent connections) and possibly
4566 buffer-overflow or denial-of-service attacks.
4569 NAME: reply_header_max_size
4573 LOC: Config.maxReplyHeaderSize
4575 This specifies the maximum size for HTTP headers in a reply.
4576 Reply headers are usually relatively small (about 512 bytes).
4577 Placing a limit on the reply header size will catch certain
4578 bugs (for example with persistent connections) and possibly
4579 buffer-overflow or denial-of-service attacks.
4582 NAME: request_body_max_size
4586 LOC: Config.maxRequestBodySize
4588 This specifies the maximum size for an HTTP request body.
4589 In other words, the maximum size of a PUT/POST request.
4590 A user who attempts to send a request with a body larger
4591 than this limit receives an "Invalid Request" error message.
4592 If you set this parameter to a zero (the default), there will
4593 be no limit imposed.
4596 NAME: client_request_buffer_max_size
4600 LOC: Config.maxRequestBufferSize
4602 This specifies the maximum buffer size of a client request.
4603 It prevents squid eating too much memory when somebody uploads
4607 NAME: chunked_request_body_max_size
4611 LOC: Config.maxChunkedRequestBodySize
4613 A broken or confused HTTP/1.1 client may send a chunked HTTP
4614 request to Squid. Squid does not have full support for that
4615 feature yet. To cope with such requests, Squid buffers the
4616 entire request and then dechunks request body to create a
4617 plain HTTP/1.0 request with a known content length. The plain
4618 request is then used by the rest of Squid code as usual.
4620 The option value specifies the maximum size of the buffer used
4621 to hold the request before the conversion. If the chunked
4622 request size exceeds the specified limit, the conversion
4623 fails, and the client receives an "unsupported request" error,
4624 as if dechunking was disabled.
4626 Dechunking is enabled by default. To disable conversion of
4627 chunked requests, set the maximum to zero.
4629 Request dechunking feature and this option in particular are a
4630 temporary hack. When chunking requests and responses are fully
4631 supported, there will be no need to buffer a chunked request.
4635 IFDEF: USE_HTTP_VIOLATIONS
4638 LOC: Config.accessList.brokenPosts
4640 A list of ACL elements which, if matched, causes Squid to send
4641 an extra CRLF pair after the body of a PUT/POST request.
4643 Some HTTP servers has broken implementations of PUT/POST,
4644 and rely on an extra CRLF pair sent by some WWW clients.
4646 Quote from RFC2616 section 4.1 on this matter:
4648 Note: certain buggy HTTP/1.0 client implementations generate an
4649 extra CRLF's after a POST request. To restate what is explicitly
4650 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
4651 a request with an extra CRLF.
4653 This clause only supports fast acl types.
4654 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4657 acl buggy_server url_regex ^http://....
4658 broken_posts allow buggy_server
4661 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
4664 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
4666 LOC: Adaptation::Config::use_indirect_client
4668 Controls whether the indirect client IP address (instead of the direct
4669 client IP address) is passed to adaptation services.
4671 See also: follow_x_forwarded_for adaptation_send_client_ip
4675 IFDEF: USE_HTTP_VIOLATIONS
4679 LOC: Config.onoff.via
4681 If set (default), Squid will include a Via header in requests and
4682 replies as required by RFC2616.
4688 LOC: Config.onoff.ie_refresh
4691 Microsoft Internet Explorer up until version 5.5 Service
4692 Pack 1 has an issue with transparent proxies, wherein it
4693 is impossible to force a refresh. Turning this on provides
4694 a partial fix to the problem, by causing all IMS-REFRESH
4695 requests from older IE versions to check the origin server
4696 for fresh content. This reduces hit ratio by some amount
4697 (~10% in my experience), but allows users to actually get
4698 fresh content when they want it. Note because Squid
4699 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
4700 of 5.5 is unchanged from old versions of Squid (i.e. a
4701 forced refresh is impossible). Newer versions of IE will,
4702 hopefully, continue to have the new behavior and will be
4703 handled based on that assumption. This option defaults to
4704 the old Squid behavior, which is better for hit ratios but
4705 worse for clients using IE, if they need to be able to
4706 force fresh content.
4709 NAME: vary_ignore_expire
4712 LOC: Config.onoff.vary_ignore_expire
4715 Many HTTP servers supporting Vary gives such objects
4716 immediate expiry time with no cache-control header
4717 when requested by a HTTP/1.0 client. This option
4718 enables Squid to ignore such expiry times until
4719 HTTP/1.1 is fully implemented.
4721 WARNING: If turned on this may eventually cause some
4722 varying objects not intended for caching to get cached.
4725 NAME: request_entities
4727 LOC: Config.onoff.request_entities
4730 Squid defaults to deny GET and HEAD requests with request entities,
4731 as the meaning of such requests are undefined in the HTTP standard
4732 even if not explicitly forbidden.
4734 Set this directive to on if you have clients which insists
4735 on sending request entities in GET or HEAD requests. But be warned
4736 that there is server software (both proxies and web servers) which
4737 can fail to properly process this kind of request which may make you
4738 vulnerable to cache pollution attacks if enabled.
4741 NAME: request_header_access
4742 IFDEF: USE_HTTP_VIOLATIONS
4743 TYPE: http_header_access
4744 LOC: Config.request_header_access
4747 Usage: request_header_access header_name allow|deny [!]aclname ...
4749 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4750 this feature could make you liable for problems which it
4753 This option replaces the old 'anonymize_headers' and the
4754 older 'http_anonymizer' option with something that is much
4755 more configurable. A list of ACLs for each header name allows
4756 removal of specific header fields under specific conditions.
4758 This option only applies to outgoing HTTP request headers (i.e.,
4759 headers sent by Squid to the next HTTP hop such as a cache peer
4760 or an origin server). The option has no effect during cache hit
4761 detection. The equivalent adaptation vectoring point in ICAP
4762 terminology is post-cache REQMOD.
4764 The option is applied to individual outgoing request header
4765 fields. For each request header field F, Squid uses the first
4766 qualifying sets of request_header_access rules:
4768 1. Rules with header_name equal to F's name.
4769 2. Rules with header_name 'Other', provided F's name is not
4770 on the hard-coded list of commonly used HTTP header names.
4771 3. Rules with header_name 'All'.
4773 Within that qualifying rule set, rule ACLs are checked as usual.
4774 If ACLs of an "allow" rule match, the header field is allowed to
4775 go through as is. If ACLs of a "deny" rule match, the header is
4776 removed and request_header_replace is then checked to identify
4777 if the removed header has a replacement. If no rules within the
4778 set have matching ACLs, the header field is left as is.
4780 For example, to achieve the same behavior as the old
4781 'http_anonymizer standard' option, you should use:
4783 request_header_access From deny all
4784 request_header_access Referer deny all
4785 request_header_access Server deny all
4786 request_header_access User-Agent deny all
4787 request_header_access WWW-Authenticate deny all
4788 request_header_access Link deny all
4790 Or, to reproduce the old 'http_anonymizer paranoid' feature
4793 request_header_access Allow allow all
4794 request_header_access Authorization allow all
4795 request_header_access WWW-Authenticate allow all
4796 request_header_access Proxy-Authorization allow all
4797 request_header_access Proxy-Authenticate allow all
4798 request_header_access Cache-Control allow all
4799 request_header_access Content-Encoding allow all
4800 request_header_access Content-Length allow all
4801 request_header_access Content-Type allow all
4802 request_header_access Date allow all
4803 request_header_access Expires allow all
4804 request_header_access Host allow all
4805 request_header_access If-Modified-Since allow all
4806 request_header_access Last-Modified allow all
4807 request_header_access Location allow all
4808 request_header_access Pragma allow all
4809 request_header_access Accept allow all
4810 request_header_access Accept-Charset allow all
4811 request_header_access Accept-Encoding allow all
4812 request_header_access Accept-Language allow all
4813 request_header_access Content-Language allow all
4814 request_header_access Mime-Version allow all
4815 request_header_access Retry-After allow all
4816 request_header_access Title allow all
4817 request_header_access Connection allow all
4818 request_header_access All deny all
4820 although many of those are HTTP reply headers, and so should be
4821 controlled with the reply_header_access directive.
4823 By default, all headers are allowed (no anonymizing is
4827 NAME: reply_header_access
4828 IFDEF: USE_HTTP_VIOLATIONS
4829 TYPE: http_header_access
4830 LOC: Config.reply_header_access
4833 Usage: reply_header_access header_name allow|deny [!]aclname ...
4835 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4836 this feature could make you liable for problems which it
4839 This option only applies to reply headers, i.e., from the
4840 server to the client.
4842 This is the same as request_header_access, but in the other
4843 direction. Please see request_header_access for detailed
4846 For example, to achieve the same behavior as the old
4847 'http_anonymizer standard' option, you should use:
4849 reply_header_access From deny all
4850 reply_header_access Referer deny all
4851 reply_header_access Server deny all
4852 reply_header_access User-Agent deny all
4853 reply_header_access WWW-Authenticate deny all
4854 reply_header_access Link deny all
4856 Or, to reproduce the old 'http_anonymizer paranoid' feature
4859 reply_header_access Allow allow all
4860 reply_header_access Authorization allow all
4861 reply_header_access WWW-Authenticate allow all
4862 reply_header_access Proxy-Authorization allow all
4863 reply_header_access Proxy-Authenticate allow all
4864 reply_header_access Cache-Control allow all
4865 reply_header_access Content-Encoding allow all
4866 reply_header_access Content-Length allow all
4867 reply_header_access Content-Type allow all
4868 reply_header_access Date allow all
4869 reply_header_access Expires allow all
4870 reply_header_access Host allow all
4871 reply_header_access If-Modified-Since allow all
4872 reply_header_access Last-Modified allow all
4873 reply_header_access Location allow all
4874 reply_header_access Pragma allow all
4875 reply_header_access Accept allow all
4876 reply_header_access Accept-Charset allow all
4877 reply_header_access Accept-Encoding allow all
4878 reply_header_access Accept-Language allow all
4879 reply_header_access Content-Language allow all
4880 reply_header_access Mime-Version allow all
4881 reply_header_access Retry-After allow all
4882 reply_header_access Title allow all
4883 reply_header_access Connection allow all
4884 reply_header_access All deny all
4886 although the HTTP request headers won't be usefully controlled
4887 by this directive -- see request_header_access for details.
4889 By default, all headers are allowed (no anonymizing is
4893 NAME: request_header_replace header_replace
4894 IFDEF: USE_HTTP_VIOLATIONS
4895 TYPE: http_header_replace
4896 LOC: Config.request_header_access
4899 Usage: request_header_replace header_name message
4900 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
4902 This option allows you to change the contents of headers
4903 denied with request_header_access above, by replacing them
4904 with some fixed string. This replaces the old fake_user_agent
4907 This only applies to request headers, not reply headers.
4909 By default, headers are removed if denied.
4912 NAME: reply_header_replace
4913 IFDEF: USE_HTTP_VIOLATIONS
4914 TYPE: http_header_replace
4915 LOC: Config.reply_header_access
4918 Usage: reply_header_replace header_name message
4919 Example: reply_header_replace Server Foo/1.0
4921 This option allows you to change the contents of headers
4922 denied with reply_header_access above, by replacing them
4923 with some fixed string.
4925 This only applies to reply headers, not request headers.
4927 By default, headers are removed if denied.
4930 NAME: request_header_add
4931 TYPE: HeaderWithAclList
4932 LOC: Config.request_header_add
4935 Usage: request_header_add field-name field-value acl1 [acl2] ...
4936 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
4938 This option adds header fields to outgoing HTTP requests (i.e.,
4939 request headers sent by Squid to the next HTTP hop such as a
4940 cache peer or an origin server). The option has no effect during
4941 cache hit detection. The equivalent adaptation vectoring point
4942 in ICAP terminology is post-cache REQMOD.
4944 Field-name is a token specifying an HTTP header name. If a
4945 standard HTTP header name is used, Squid does not check whether
4946 the new header conflicts with any existing headers or violates
4947 HTTP rules. If the request to be modified already contains a
4948 field with the same name, the old field is preserved but the
4949 header field values are not merged.
4951 Field-value is either a token or a quoted string. If quoted
4952 string format is used, then the surrounding quotes are removed
4953 while escape sequences and %macros are processed.
4955 In theory, all of the logformat codes can be used as %macros.
4956 However, unlike logging (which happens at the very end of
4957 transaction lifetime), the transaction may not yet have enough
4958 information to expand a macro when the new header value is needed.
4959 And some information may already be available to Squid but not yet
4960 committed where the macro expansion code can access it (report
4961 such instances!). The macro will be expanded into a single dash
4962 ('-') in such cases. Not all macros have been tested.
4964 One or more Squid ACLs may be specified to restrict header
4965 injection to matching requests. As always in squid.conf, all
4966 ACLs in an option ACL list must be satisfied for the insertion
4967 to happen. The request_header_add option supports fast ACLs
4976 This option used to log custom information about the master
4977 transaction. For example, an admin may configure Squid to log
4978 which "user group" the transaction belongs to, where "user group"
4979 will be determined based on a set of ACLs and not [just]
4980 authentication information.
4981 Values of key/value pairs can be logged using %{key}note macros:
4983 note key value acl ...
4984 logformat myFormat ... %{key}note ...
4987 NAME: relaxed_header_parser
4988 COMMENT: on|off|warn
4990 LOC: Config.onoff.relaxed_header_parser
4993 In the default "on" setting Squid accepts certain forms
4994 of non-compliant HTTP messages where it is unambiguous
4995 what the sending application intended even if the message
4996 is not correctly formatted. The messages is then normalized
4997 to the correct form when forwarded by Squid.
4999 If set to "warn" then a warning will be emitted in cache.log
5000 each time such HTTP error is encountered.
5002 If set to "off" then such HTTP errors will cause the request
5003 or response to be rejected.
5008 -----------------------------------------------------------------------------
5011 NAME: forward_timeout
5014 LOC: Config.Timeout.forward
5017 This parameter specifies how long Squid should at most attempt in
5018 finding a forwarding path for the request before giving up.
5021 NAME: connect_timeout
5024 LOC: Config.Timeout.connect
5027 This parameter specifies how long to wait for the TCP connect to
5028 the requested server or peer to complete before Squid should
5029 attempt to find another path where to forward the request.
5032 NAME: peer_connect_timeout
5035 LOC: Config.Timeout.peer_connect
5038 This parameter specifies how long to wait for a pending TCP
5039 connection to a peer cache. The default is 30 seconds. You
5040 may also set different timeout values for individual neighbors
5041 with the 'connect-timeout' option on a 'cache_peer' line.
5047 LOC: Config.Timeout.read
5050 The read_timeout is applied on server-side connections. After
5051 each successful read(), the timeout will be extended by this
5052 amount. If no data is read again after this amount of time,
5053 the request is aborted and logged with ERR_READ_TIMEOUT. The
5054 default is 15 minutes.
5060 LOC: Config.Timeout.write
5063 This timeout is tracked for all connections that have data
5064 available for writing and are waiting for the socket to become
5065 ready. After each successful write, the timeout is extended by
5066 the configured amount. If Squid has data to write but the
5067 connection is not ready for the configured duration, the
5068 transaction associated with the connection is terminated. The
5069 default is 15 minutes.
5072 NAME: request_timeout
5074 LOC: Config.Timeout.request
5077 How long to wait for complete HTTP request headers after initial
5078 connection establishment.
5081 NAME: client_idle_pconn_timeout persistent_request_timeout
5083 LOC: Config.Timeout.clientIdlePconn
5086 How long to wait for the next HTTP request on a persistent
5087 client connection after the previous request completes.
5090 NAME: client_lifetime
5093 LOC: Config.Timeout.lifetime
5096 The maximum amount of time a client (browser) is allowed to
5097 remain connected to the cache process. This protects the Cache
5098 from having a lot of sockets (and hence file descriptors) tied up
5099 in a CLOSE_WAIT state from remote clients that go away without
5100 properly shutting down (either because of a network failure or
5101 because of a poor client implementation). The default is one
5104 NOTE: The default value is intended to be much larger than any
5105 client would ever need to be connected to your cache. You
5106 should probably change client_lifetime only as a last resort.
5107 If you seem to have many client connections tying up
5108 filedescriptors, we recommend first tuning the read_timeout,
5109 request_timeout, persistent_request_timeout and quick_abort values.
5112 NAME: half_closed_clients
5114 LOC: Config.onoff.half_closed_clients
5117 Some clients may shutdown the sending side of their TCP
5118 connections, while leaving their receiving sides open. Sometimes,
5119 Squid can not tell the difference between a half-closed and a
5120 fully-closed TCP connection.
5122 By default, Squid will immediately close client connections when
5123 read(2) returns "no more data to read."
5125 Change this option to 'on' and Squid will keep open connections
5126 until a read(2) or write(2) on the socket returns an error.
5127 This may show some benefits for reverse proxies. But if not
5128 it is recommended to leave OFF.
5131 NAME: server_idle_pconn_timeout pconn_timeout
5133 LOC: Config.Timeout.serverIdlePconn
5136 Timeout for idle persistent connections to servers and other
5143 LOC: Ident::TheConfig.timeout
5146 Maximum time to wait for IDENT lookups to complete.
5148 If this is too high, and you enabled IDENT lookups from untrusted
5149 users, you might be susceptible to denial-of-service by having
5150 many ident requests going at once.
5153 NAME: shutdown_lifetime
5156 LOC: Config.shutdownLifetime
5159 When SIGTERM or SIGHUP is received, the cache is put into
5160 "shutdown pending" mode until all active sockets are closed.
5161 This value is the lifetime to set for all open descriptors
5162 during shutdown mode. Any active clients after this many
5163 seconds will receive a 'timeout' message.
5167 ADMINISTRATIVE PARAMETERS
5168 -----------------------------------------------------------------------------
5174 LOC: Config.adminEmail
5176 Email-address of local cache manager who will receive
5177 mail if the cache dies. The default is "webmaster."
5183 LOC: Config.EmailFrom
5185 From: email-address for mail sent when the cache dies.
5186 The default is to use 'appname@unique_hostname'.
5187 Default appname value is "squid", can be changed into
5188 src/globals.h before building squid.
5194 LOC: Config.EmailProgram
5196 Email program used to send mail if the cache dies.
5197 The default is "mail". The specified program must comply
5198 with the standard Unix mail syntax:
5199 mail-program recipient < mailfile
5201 Optional command line options can be specified.
5204 NAME: cache_effective_user
5206 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
5207 LOC: Config.effectiveUser
5209 If you start Squid as root, it will change its effective/real
5210 UID/GID to the user specified below. The default is to change
5211 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
5212 see also; cache_effective_group
5215 NAME: cache_effective_group
5218 LOC: Config.effectiveGroup
5220 Squid sets the GID to the effective user's default group ID
5221 (taken from the password file) and supplementary group list
5222 from the groups membership.
5224 If you want Squid to run with a specific GID regardless of
5225 the group memberships of the effective user then set this
5226 to the group (or GID) you want Squid to run as. When set
5227 all other group privileges of the effective user are ignored
5228 and only this GID is effective. If Squid is not started as
5229 root the user starting Squid MUST be member of the specified
5232 This option is not recommended by the Squid Team.
5233 Our preference is for administrators to configure a secure
5234 user account for squid with UID/GID matching system policies.
5237 NAME: httpd_suppress_version_string
5241 LOC: Config.onoff.httpd_suppress_version_string
5243 Suppress Squid version string info in HTTP headers and HTML error pages.
5246 NAME: visible_hostname
5248 LOC: Config.visibleHostname
5251 If you want to present a special hostname in error messages, etc,
5252 define this. Otherwise, the return value of gethostname()
5253 will be used. If you have multiple caches in a cluster and
5254 get errors about IP-forwarding you must set them to have individual
5255 names with this setting.
5258 NAME: unique_hostname
5260 LOC: Config.uniqueHostname
5263 If you want to have multiple machines with the same
5264 'visible_hostname' you must give each machine a different
5265 'unique_hostname' so forwarding loops can be detected.
5268 NAME: hostname_aliases
5270 LOC: Config.hostnameAliases
5273 A list of other DNS names your cache has.
5281 Minimum umask which should be enforced while the proxy
5282 is running, in addition to the umask set at startup.
5284 For a traditional octal representation of umasks, start
5289 OPTIONS FOR THE CACHE REGISTRATION SERVICE
5290 -----------------------------------------------------------------------------
5292 This section contains parameters for the (optional) cache
5293 announcement service. This service is provided to help
5294 cache administrators locate one another in order to join or
5295 create cache hierarchies.
5297 An 'announcement' message is sent (via UDP) to the registration
5298 service by Squid. By default, the announcement message is NOT
5299 SENT unless you enable it with 'announce_period' below.
5301 The announcement message includes your hostname, plus the
5302 following information from this configuration file:
5308 All current information is processed regularly and made
5309 available on the Web at http://www.ircache.net/Cache/Tracker/.
5312 NAME: announce_period
5314 LOC: Config.Announce.period
5317 This is how frequently to send cache announcements. The
5318 default is `0' which disables sending the announcement
5321 To enable announcing your cache, just set an announce period.
5324 announce_period 1 day
5329 DEFAULT: tracker.ircache.net
5330 LOC: Config.Announce.host
5336 LOC: Config.Announce.file
5342 LOC: Config.Announce.port
5344 announce_host and announce_port set the hostname and port
5345 number where the registration message will be sent.
5347 Hostname will default to 'tracker.ircache.net' and port will
5348 default default to 3131. If the 'filename' argument is given,
5349 the contents of that file will be included in the announce
5354 HTTPD-ACCELERATOR OPTIONS
5355 -----------------------------------------------------------------------------
5358 NAME: httpd_accel_surrogate_id
5361 LOC: Config.Accel.surrogate_id
5363 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
5364 need an identification token to allow control targeting. Because
5365 a farm of surrogates may all perform the same tasks, they may share
5366 an identification token.
5368 The default ID is the visible_hostname
5371 NAME: http_accel_surrogate_remote
5375 LOC: Config.onoff.surrogate_is_remote
5377 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
5378 Set this to on to have squid behave as a remote surrogate.
5382 IFDEF: USE_SQUID_ESI
5383 COMMENT: libxml2|expat|custom
5385 LOC: ESIParser::Type
5388 ESI markup is not strictly XML compatible. The custom ESI parser
5389 will give higher performance, but cannot handle non ASCII character
5394 DELAY POOL PARAMETERS
5395 -----------------------------------------------------------------------------
5399 TYPE: delay_pool_count
5401 IFDEF: USE_DELAY_POOLS
5404 This represents the number of delay pools to be used. For example,
5405 if you have one class 2 delay pool and one class 3 delays pool, you
5406 have a total of 2 delay pools.
5410 TYPE: delay_pool_class
5412 IFDEF: USE_DELAY_POOLS
5415 This defines the class of each delay pool. There must be exactly one
5416 delay_class line for each delay pool. For example, to define two
5417 delay pools, one of class 2 and one of class 3, the settings above
5421 delay_pools 4 # 4 delay pools
5422 delay_class 1 2 # pool 1 is a class 2 pool
5423 delay_class 2 3 # pool 2 is a class 3 pool
5424 delay_class 3 4 # pool 3 is a class 4 pool
5425 delay_class 4 5 # pool 4 is a class 5 pool
5427 The delay pool classes are:
5429 class 1 Everything is limited by a single aggregate
5432 class 2 Everything is limited by a single aggregate
5433 bucket as well as an "individual" bucket chosen
5434 from bits 25 through 32 of the IPv4 address.
5436 class 3 Everything is limited by a single aggregate
5437 bucket as well as a "network" bucket chosen
5438 from bits 17 through 24 of the IP address and a
5439 "individual" bucket chosen from bits 17 through
5440 32 of the IPv4 address.
5442 class 4 Everything in a class 3 delay pool, with an
5443 additional limit on a per user basis. This
5444 only takes effect if the username is established
5445 in advance - by forcing authentication in your
5448 class 5 Requests are grouped according their tag (see
5449 external_acl's tag= reply).
5452 Each pool also requires a delay_parameters directive to configure the pool size
5453 and speed limits used whenever the pool is applied to a request. Along with
5454 a set of delay_access directives to determine when it is used.
5456 NOTE: If an IP address is a.b.c.d
5457 -> bits 25 through 32 are "d"
5458 -> bits 17 through 24 are "c"
5459 -> bits 17 through 32 are "c * 256 + d"
5461 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
5462 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
5466 TYPE: delay_pool_access
5468 IFDEF: USE_DELAY_POOLS
5471 This is used to determine which delay pool a request falls into.
5473 delay_access is sorted per pool and the matching starts with pool 1,
5474 then pool 2, ..., and finally pool N. The first delay pool where the
5475 request is allowed is selected for the request. If it does not allow
5476 the request to any pool then the request is not delayed (default).
5478 For example, if you want some_big_clients in delay
5479 pool 1 and lotsa_little_clients in delay pool 2:
5482 delay_access 1 allow some_big_clients
5483 delay_access 1 deny all
5484 delay_access 2 allow lotsa_little_clients
5485 delay_access 2 deny all
5486 delay_access 3 allow authenticated_clients
5489 NAME: delay_parameters
5490 TYPE: delay_pool_rates
5492 IFDEF: USE_DELAY_POOLS
5495 This defines the parameters for a delay pool. Each delay pool has
5496 a number of "buckets" associated with it, as explained in the
5497 description of delay_class.
5499 For a class 1 delay pool, the syntax is:
5501 delay_parameters pool aggregate
5503 For a class 2 delay pool:
5505 delay_parameters pool aggregate individual
5507 For a class 3 delay pool:
5509 delay_parameters pool aggregate network individual
5511 For a class 4 delay pool:
5513 delay_parameters pool aggregate network individual user
5515 For a class 5 delay pool:
5517 delay_parameters pool tagrate
5519 The option variables are:
5521 pool a pool number - ie, a number between 1 and the
5522 number specified in delay_pools as used in
5525 aggregate the speed limit parameters for the aggregate bucket
5528 individual the speed limit parameters for the individual
5529 buckets (class 2, 3).
5531 network the speed limit parameters for the network buckets
5534 user the speed limit parameters for the user buckets
5537 tagrate the speed limit parameters for the tag buckets
5540 A pair of delay parameters is written restore/maximum, where restore is
5541 the number of bytes (not bits - modem and network speeds are usually
5542 quoted in bits) per second placed into the bucket, and maximum is the
5543 maximum number of bytes which can be in the bucket at any time.
5545 There must be one delay_parameters line for each delay pool.
5548 For example, if delay pool number 1 is a class 2 delay pool as in the
5549 above example, and is being used to strictly limit each host to 64Kbit/sec
5550 (plus overheads), with no overall limit, the line is:
5552 delay_parameters 1 -1/-1 8000/8000
5554 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
5556 Note that the figure -1 is used to represent "unlimited".
5559 And, if delay pool number 2 is a class 3 delay pool as in the above
5560 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
5561 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
5562 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
5563 to permit a decent web page to be downloaded at a decent speed
5564 (if the network is not being limited due to overuse) but slow down
5565 large downloads more significantly:
5567 delay_parameters 2 32000/32000 8000/8000 600/8000
5569 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
5570 8 x 8000 KByte/sec -> 64Kbit/sec.
5571 8 x 600 Byte/sec -> 4800bit/sec.
5574 Finally, for a class 4 delay pool as in the example - each user will
5575 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
5577 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
5580 NAME: delay_initial_bucket_level
5581 COMMENT: (percent, 0-100)
5584 IFDEF: USE_DELAY_POOLS
5585 LOC: Config.Delay.initial
5587 The initial bucket percentage is used to determine how much is put
5588 in each bucket when squid starts, is reconfigured, or first notices
5589 a host accessing it (in class 2 and class 3, individual hosts and
5590 networks only have buckets associated with them once they have been
5595 CLIENT DELAY POOL PARAMETERS
5596 -----------------------------------------------------------------------------
5599 NAME: client_delay_pools
5600 TYPE: client_delay_pool_count
5602 IFDEF: USE_DELAY_POOLS
5603 LOC: Config.ClientDelay
5605 This option specifies the number of client delay pools used. It must
5606 preceed other client_delay_* options.
5609 client_delay_pools 2
5612 NAME: client_delay_initial_bucket_level
5613 COMMENT: (percent, 0-no_limit)
5616 IFDEF: USE_DELAY_POOLS
5617 LOC: Config.ClientDelay.initial
5619 This option determines the initial bucket size as a percentage of
5620 max_bucket_size from client_delay_parameters. Buckets are created
5621 at the time of the "first" connection from the matching IP. Idle
5622 buckets are periodically deleted up.
5624 You can specify more than 100 percent but note that such "oversized"
5625 buckets are not refilled until their size goes down to max_bucket_size
5626 from client_delay_parameters.
5629 client_delay_initial_bucket_level 50
5632 NAME: client_delay_parameters
5633 TYPE: client_delay_pool_rates
5635 IFDEF: USE_DELAY_POOLS
5636 LOC: Config.ClientDelay
5639 This option configures client-side bandwidth limits using the
5642 client_delay_parameters pool speed_limit max_bucket_size
5644 pool is an integer ID used for client_delay_access matching.
5646 speed_limit is bytes added to the bucket per second.
5648 max_bucket_size is the maximum size of a bucket, enforced after any
5649 speed_limit additions.
5651 Please see the delay_parameters option for more information and
5655 client_delay_parameters 1 1024 2048
5656 client_delay_parameters 2 51200 16384
5659 NAME: client_delay_access
5660 TYPE: client_delay_pool_access
5662 IFDEF: USE_DELAY_POOLS
5663 LOC: Config.ClientDelay
5666 This option determines the client-side delay pool for the
5669 client_delay_access pool_ID allow|deny acl_name
5671 All client_delay_access options are checked in their pool ID
5672 order, starting with pool 1. The first checked pool with allowed
5673 request is selected for the request. If no ACL matches or there
5674 are no client_delay_access options, the request bandwidth is not
5677 The ACL-selected pool is then used to find the
5678 client_delay_parameters for the request. Client-side pools are
5679 not used to aggregate clients. Clients are always aggregated
5680 based on their source IP addresses (one bucket per source IP).
5682 Please see delay_access for more examples.
5685 client_delay_access 1 allow low_rate_network
5686 client_delay_access 2 allow vips_network
5690 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
5691 -----------------------------------------------------------------------------
5696 LOC: Config.Wccp.router
5700 Use this option to define your WCCP ``home'' router for
5703 wccp_router supports a single WCCP(v1) router
5705 wccp2_router supports multiple WCCPv2 routers
5707 only one of the two may be used at the same time and defines
5708 which version of WCCP to use.
5712 TYPE: IpAddress_list
5713 LOC: Config.Wccp2.router
5717 Use this option to define your WCCP ``home'' router for
5720 wccp_router supports a single WCCP(v1) router
5722 wccp2_router supports multiple WCCPv2 routers
5724 only one of the two may be used at the same time and defines
5725 which version of WCCP to use.
5730 LOC: Config.Wccp.version
5734 This directive is only relevant if you need to set up WCCP(v1)
5735 to some very old and end-of-life Cisco routers. In all other
5736 setups it must be left unset or at the default setting.
5737 It defines an internal version in the WCCP(v1) protocol,
5738 with version 4 being the officially documented protocol.
5740 According to some users, Cisco IOS 11.2 and earlier only
5741 support WCCP version 3. If you're using that or an earlier
5742 version of IOS, you may need to change this value to 3, otherwise
5743 do not specify this parameter.
5746 NAME: wccp2_rebuild_wait
5748 LOC: Config.Wccp2.rebuildwait
5752 If this is enabled Squid will wait for the cache dir rebuild to finish
5753 before sending the first wccp2 HereIAm packet
5756 NAME: wccp2_forwarding_method
5758 LOC: Config.Wccp2.forwarding_method
5762 WCCP2 allows the setting of forwarding methods between the
5763 router/switch and the cache. Valid values are as follows:
5765 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5766 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5768 Currently (as of IOS 12.4) cisco routers only support GRE.
5769 Cisco switches only support the L2 redirect assignment method.
5772 NAME: wccp2_return_method
5774 LOC: Config.Wccp2.return_method
5778 WCCP2 allows the setting of return methods between the
5779 router/switch and the cache for packets that the cache
5780 decides not to handle. Valid values are as follows:
5782 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5783 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5785 Currently (as of IOS 12.4) cisco routers only support GRE.
5786 Cisco switches only support the L2 redirect assignment.
5788 If the "ip wccp redirect exclude in" command has been
5789 enabled on the cache interface, then it is still safe for
5790 the proxy server to use a l2 redirect method even if this
5791 option is set to GRE.
5794 NAME: wccp2_assignment_method
5796 LOC: Config.Wccp2.assignment_method
5800 WCCP2 allows the setting of methods to assign the WCCP hash
5801 Valid values are as follows:
5803 hash - Hash assignment
5804 mask - Mask assignment
5806 As a general rule, cisco routers support the hash assignment method
5807 and cisco switches support the mask assignment method.
5812 LOC: Config.Wccp2.info
5813 DEFAULT_IF_NONE: standard 0
5816 WCCP2 allows for multiple traffic services. There are two
5817 types: "standard" and "dynamic". The standard type defines
5818 one service id - http (id 0). The dynamic service ids can be from
5819 51 to 255 inclusive. In order to use a dynamic service id
5820 one must define the type of traffic to be redirected; this is done
5821 using the wccp2_service_info option.
5823 The "standard" type does not require a wccp2_service_info option,
5824 just specifying the service id will suffice.
5826 MD5 service authentication can be enabled by adding
5827 "password=<password>" to the end of this service declaration.
5831 wccp2_service standard 0 # for the 'web-cache' standard service
5832 wccp2_service dynamic 80 # a dynamic service type which will be
5833 # fleshed out with subsequent options.
5834 wccp2_service standard 0 password=foo
5837 NAME: wccp2_service_info
5838 TYPE: wccp2_service_info
5839 LOC: Config.Wccp2.info
5843 Dynamic WCCPv2 services require further information to define the
5844 traffic you wish to have diverted.
5848 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
5849 priority=<priority> ports=<port>,<port>..
5851 The relevant WCCPv2 flags:
5852 + src_ip_hash, dst_ip_hash
5853 + source_port_hash, dst_port_hash
5854 + src_ip_alt_hash, dst_ip_alt_hash
5855 + src_port_alt_hash, dst_port_alt_hash
5858 The port list can be one to eight entries.
5862 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
5863 priority=240 ports=80
5865 Note: the service id must have been defined by a previous
5866 'wccp2_service dynamic <id>' entry.
5871 LOC: Config.Wccp2.weight
5875 Each cache server gets assigned a set of the destination
5876 hash proportional to their weight.
5881 LOC: Config.Wccp.address
5888 LOC: Config.Wccp2.address
5892 Use this option if you require WCCP to use a specific
5895 The default behavior is to not bind to any specific address.
5899 PERSISTENT CONNECTION HANDLING
5900 -----------------------------------------------------------------------------
5902 Also see "pconn_timeout" in the TIMEOUTS section
5905 NAME: client_persistent_connections
5907 LOC: Config.onoff.client_pconns
5911 NAME: server_persistent_connections
5913 LOC: Config.onoff.server_pconns
5916 Persistent connection support for clients and servers. By
5917 default, Squid uses persistent connections (when allowed)
5918 with its clients and servers. You can use these options to
5919 disable persistent connections with clients and/or servers.
5922 NAME: persistent_connection_after_error
5924 LOC: Config.onoff.error_pconns
5927 With this directive the use of persistent connections after
5928 HTTP errors can be disabled. Useful if you have clients
5929 who fail to handle errors on persistent connections proper.
5932 NAME: detect_broken_pconn
5934 LOC: Config.onoff.detect_broken_server_pconns
5937 Some servers have been found to incorrectly signal the use
5938 of HTTP/1.0 persistent connections even on replies not
5939 compatible, causing significant delays. This server problem
5940 has mostly been seen on redirects.
5942 By enabling this directive Squid attempts to detect such
5943 broken replies and automatically assume the reply is finished
5944 after 10 seconds timeout.
5948 CACHE DIGEST OPTIONS
5949 -----------------------------------------------------------------------------
5952 NAME: digest_generation
5953 IFDEF: USE_CACHE_DIGESTS
5955 LOC: Config.onoff.digest_generation
5958 This controls whether the server will generate a Cache Digest
5959 of its contents. By default, Cache Digest generation is
5960 enabled if Squid is compiled with --enable-cache-digests defined.
5963 NAME: digest_bits_per_entry
5964 IFDEF: USE_CACHE_DIGESTS
5966 LOC: Config.digest.bits_per_entry
5969 This is the number of bits of the server's Cache Digest which
5970 will be associated with the Digest entry for a given HTTP
5971 Method and URL (public key) combination. The default is 5.
5974 NAME: digest_rebuild_period
5975 IFDEF: USE_CACHE_DIGESTS
5978 LOC: Config.digest.rebuild_period
5981 This is the wait time between Cache Digest rebuilds.
5984 NAME: digest_rewrite_period
5986 IFDEF: USE_CACHE_DIGESTS
5988 LOC: Config.digest.rewrite_period
5991 This is the wait time between Cache Digest writes to
5995 NAME: digest_swapout_chunk_size
5998 IFDEF: USE_CACHE_DIGESTS
5999 LOC: Config.digest.swapout_chunk_size
6002 This is the number of bytes of the Cache Digest to write to
6003 disk at a time. It defaults to 4096 bytes (4KB), the Squid
6007 NAME: digest_rebuild_chunk_percentage
6008 COMMENT: (percent, 0-100)
6009 IFDEF: USE_CACHE_DIGESTS
6011 LOC: Config.digest.rebuild_chunk_percentage
6014 This is the percentage of the Cache Digest to be scanned at a
6015 time. By default it is set to 10% of the Cache Digest.
6020 -----------------------------------------------------------------------------
6025 LOC: Config.Port.snmp
6029 The port number where Squid listens for SNMP requests. To enable
6030 SNMP support set this to a suitable port number. Port number
6031 3401 is often used for the Squid SNMP agent. By default it's
6032 set to "0" (disabled)
6040 LOC: Config.accessList.snmp
6041 DEFAULT_IF_NONE: deny all
6044 Allowing or denying access to the SNMP port.
6046 All access to the agent is denied by default.
6049 snmp_access allow|deny [!]aclname ...
6051 This clause only supports fast acl types.
6052 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6054 snmp_access allow snmppublic localhost
6055 snmp_access deny all
6058 NAME: snmp_incoming_address
6060 LOC: Config.Addrs.snmp_incoming
6065 NAME: snmp_outgoing_address
6067 LOC: Config.Addrs.snmp_outgoing
6071 Just like 'udp_incoming_address', but for the SNMP port.
6073 snmp_incoming_address is used for the SNMP socket receiving
6074 messages from SNMP agents.
6075 snmp_outgoing_address is used for SNMP packets returned to SNMP
6078 The default snmp_incoming_address is to listen on all
6079 available network interfaces.
6081 If snmp_outgoing_address is not set it will use the same socket
6082 as snmp_incoming_address. Only change this if you want to have
6083 SNMP replies sent using another address than where this Squid
6084 listens for SNMP queries.
6086 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
6087 the same value since they both use port 3401.
6092 -----------------------------------------------------------------------------
6095 NAME: icp_port udp_port
6098 LOC: Config.Port.icp
6100 The port number where Squid sends and receives ICP queries to
6101 and from neighbor caches. The standard UDP port for ICP is 3130.
6102 Default is disabled (0).
6105 icp_port @DEFAULT_ICP_PORT@
6112 LOC: Config.Port.htcp
6114 The port number where Squid sends and receives HTCP queries to
6115 and from neighbor caches. To turn it on you want to set it to
6116 4827. By default it is set to "0" (disabled).
6122 NAME: log_icp_queries
6126 LOC: Config.onoff.log_udp
6128 If set, ICP queries are logged to access.log. You may wish
6129 do disable this if your ICP load is VERY high to speed things
6130 up or to simplify log analysis.
6133 NAME: udp_incoming_address
6135 LOC:Config.Addrs.udp_incoming
6138 udp_incoming_address is used for UDP packets received from other
6141 The default behavior is to not bind to any specific address.
6143 Only change this if you want to have all UDP queries received on
6144 a specific interface/address.
6146 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
6147 modules. Altering it will affect all of them in the same manner.
6149 see also; udp_outgoing_address
6151 NOTE, udp_incoming_address and udp_outgoing_address can not
6152 have the same value since they both use the same port.
6155 NAME: udp_outgoing_address
6157 LOC: Config.Addrs.udp_outgoing
6160 udp_outgoing_address is used for UDP packets sent out to other
6163 The default behavior is to not bind to any specific address.
6165 Instead it will use the same socket as udp_incoming_address.
6166 Only change this if you want to have UDP queries sent using another
6167 address than where this Squid listens for UDP queries from other
6170 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
6171 modules. Altering it will affect all of them in the same manner.
6173 see also; udp_incoming_address
6175 NOTE, udp_incoming_address and udp_outgoing_address can not
6176 have the same value since they both use the same port.
6183 LOC: Config.onoff.icp_hit_stale
6185 If you want to return ICP_HIT for stale cache objects, set this
6186 option to 'on'. If you have sibling relationships with caches
6187 in other administrative domains, this should be 'off'. If you only
6188 have sibling relationships with caches under your control,
6189 it is probably okay to set this to 'on'.
6190 If set to 'on', your siblings should use the option "allow-miss"
6191 on their cache_peer lines for connecting to you.
6194 NAME: minimum_direct_hops
6197 LOC: Config.minDirectHops
6199 If using the ICMP pinging stuff, do direct fetches for sites
6200 which are no more than this many hops away.
6203 NAME: minimum_direct_rtt
6206 LOC: Config.minDirectRtt
6208 If using the ICMP pinging stuff, do direct fetches for sites
6209 which are no more than this many rtt milliseconds away.
6215 LOC: Config.Netdb.low
6221 LOC: Config.Netdb.high
6223 The low and high water marks for the ICMP measurement
6224 database. These are counts, not percents. The defaults are
6225 900 and 1000. When the high water mark is reached, database
6226 entries will be deleted until the low mark is reached.
6229 NAME: netdb_ping_period
6231 LOC: Config.Netdb.period
6234 The minimum period for measuring a site. There will be at
6235 least this much delay between successive pings to the same
6236 network. The default is five minutes.
6243 LOC: Config.onoff.query_icmp
6245 If you want to ask your peers to include ICMP data in their ICP
6246 replies, enable this option.
6248 If your peer has configured Squid (during compilation) with
6249 '--enable-icmp' that peer will send ICMP pings to origin server
6250 sites of the URLs it receives. If you enable this option the
6251 ICP replies from that peer will include the ICMP data (if available).
6252 Then, when choosing a parent cache, Squid will choose the parent with
6253 the minimal RTT to the origin server. When this happens, the
6254 hierarchy field of the access.log will be
6255 "CLOSEST_PARENT_MISS". This option is off by default.
6258 NAME: test_reachability
6262 LOC: Config.onoff.test_reachability
6264 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
6265 instead of ICP_MISS if the target host is NOT in the ICMP
6266 database, or has a zero RTT.
6269 NAME: icp_query_timeout
6273 LOC: Config.Timeout.icp_query
6275 Normally Squid will automatically determine an optimal ICP
6276 query timeout value based on the round-trip-time of recent ICP
6277 queries. If you want to override the value determined by
6278 Squid, set this 'icp_query_timeout' to a non-zero value. This
6279 value is specified in MILLISECONDS, so, to use a 2-second
6280 timeout (the old default), you would write:
6282 icp_query_timeout 2000
6285 NAME: maximum_icp_query_timeout
6289 LOC: Config.Timeout.icp_query_max
6291 Normally the ICP query timeout is determined dynamically. But
6292 sometimes it can lead to very large values (say 5 seconds).
6293 Use this option to put an upper limit on the dynamic timeout
6294 value. Do NOT use this option to always use a fixed (instead
6295 of a dynamic) timeout value. To set a fixed timeout see the
6296 'icp_query_timeout' directive.
6299 NAME: minimum_icp_query_timeout
6303 LOC: Config.Timeout.icp_query_min
6305 Normally the ICP query timeout is determined dynamically. But
6306 sometimes it can lead to very small timeouts, even lower than
6307 the normal latency variance on your link due to traffic.
6308 Use this option to put an lower limit on the dynamic timeout
6309 value. Do NOT use this option to always use a fixed (instead
6310 of a dynamic) timeout value. To set a fixed timeout see the
6311 'icp_query_timeout' directive.
6314 NAME: background_ping_rate
6318 LOC: Config.backgroundPingRate
6320 Controls how often the ICP pings are sent to siblings that
6321 have background-ping set.
6325 MULTICAST ICP OPTIONS
6326 -----------------------------------------------------------------------------
6331 LOC: Config.mcast_group_list
6334 This tag specifies a list of multicast groups which your server
6335 should join to receive multicasted ICP queries.
6337 NOTE! Be very careful what you put here! Be sure you
6338 understand the difference between an ICP _query_ and an ICP
6339 _reply_. This option is to be set only if you want to RECEIVE
6340 multicast queries. Do NOT set this option to SEND multicast
6341 ICP (use cache_peer for that). ICP replies are always sent via
6342 unicast, so this option does not affect whether or not you will
6343 receive replies from multicast group members.
6345 You must be very careful to NOT use a multicast address which
6346 is already in use by another group of caches.
6348 If you are unsure about multicast, please read the Multicast
6349 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
6351 Usage: mcast_groups 239.128.16.128 224.0.1.20
6353 By default, Squid doesn't listen on any multicast groups.
6356 NAME: mcast_miss_addr
6357 IFDEF: MULTICAST_MISS_STREAM
6359 LOC: Config.mcast_miss.addr
6362 If you enable this option, every "cache miss" URL will
6363 be sent out on the specified multicast address.
6365 Do not enable this option unless you are are absolutely
6366 certain you understand what you are doing.
6369 NAME: mcast_miss_ttl
6370 IFDEF: MULTICAST_MISS_STREAM
6372 LOC: Config.mcast_miss.ttl
6375 This is the time-to-live value for packets multicasted
6376 when multicasting off cache miss URLs is enabled. By
6377 default this is set to 'site scope', i.e. 16.
6380 NAME: mcast_miss_port
6381 IFDEF: MULTICAST_MISS_STREAM
6383 LOC: Config.mcast_miss.port
6386 This is the port number to be used in conjunction with
6390 NAME: mcast_miss_encode_key
6391 IFDEF: MULTICAST_MISS_STREAM
6393 LOC: Config.mcast_miss.encode_key
6394 DEFAULT: XXXXXXXXXXXXXXXX
6396 The URLs that are sent in the multicast miss stream are
6397 encrypted. This is the encryption key.
6400 NAME: mcast_icp_query_timeout
6404 LOC: Config.Timeout.mcast_icp_query
6406 For multicast peers, Squid regularly sends out ICP "probes" to
6407 count how many other peers are listening on the given multicast
6408 address. This value specifies how long Squid should wait to
6409 count all the replies. The default is 2000 msec, or 2
6414 INTERNAL ICON OPTIONS
6415 -----------------------------------------------------------------------------
6418 NAME: icon_directory
6420 LOC: Config.icons.directory
6421 DEFAULT: @DEFAULT_ICON_DIR@
6423 Where the icons are stored. These are normally kept in
6427 NAME: global_internal_static
6429 LOC: Config.onoff.global_internal_static
6432 This directive controls is Squid should intercept all requests for
6433 /squid-internal-static/ no matter which host the URL is requesting
6434 (default on setting), or if nothing special should be done for
6435 such URLs (off setting). The purpose of this directive is to make
6436 icons etc work better in complex cache hierarchies where it may
6437 not always be possible for all corners in the cache mesh to reach
6438 the server generating a directory listing.
6441 NAME: short_icon_urls
6443 LOC: Config.icons.use_short_names
6446 If this is enabled Squid will use short URLs for icons.
6447 If disabled it will revert to the old behavior of including
6448 it's own name and port in the URL.
6450 If you run a complex cache hierarchy with a mix of Squid and
6451 other proxies you may need to disable this directive.
6456 -----------------------------------------------------------------------------
6459 NAME: error_directory
6461 LOC: Config.errorDirectory
6464 If you wish to create your own versions of the default
6465 error files to customize them to suit your company copy
6466 the error/template files to another directory and point
6469 WARNING: This option will disable multi-language support
6470 on error pages if used.
6472 The squid developers are interested in making squid available in
6473 a wide variety of languages. If you are making translations for a
6474 language that Squid does not currently provide please consider
6475 contributing your translation back to the project.
6476 http://wiki.squid-cache.org/Translations
6478 The squid developers working on translations are happy to supply drop-in
6479 translated error files in exchange for any new language contributions.
6482 NAME: error_default_language
6483 IFDEF: USE_ERR_LOCALES
6485 LOC: Config.errorDefaultLanguage
6488 Set the default language which squid will send error pages in
6489 if no existing translation matches the clients language
6492 If unset (default) generic English will be used.
6494 The squid developers are interested in making squid available in
6495 a wide variety of languages. If you are interested in making
6496 translations for any language see the squid wiki for details.
6497 http://wiki.squid-cache.org/Translations
6500 NAME: error_log_languages
6501 IFDEF: USE_ERR_LOCALES
6503 LOC: Config.errorLogMissingLanguages
6506 Log to cache.log what languages users are attempting to
6507 auto-negotiate for translations.
6509 Successful negotiations are not logged. Only failures
6510 have meaning to indicate that Squid may need an upgrade
6511 of its error page translations.
6514 NAME: err_page_stylesheet
6516 LOC: Config.errorStylesheet
6517 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
6519 CSS Stylesheet to pattern the display of Squid default error pages.
6521 For information on CSS see http://www.w3.org/Style/CSS/
6526 LOC: Config.errHtmlText
6529 HTML text to include in error messages. Make this a "mailto"
6530 URL to your admin address, or maybe just a link to your
6531 organizations Web page.
6533 To include this in your error messages, you must rewrite
6534 the error template files (found in the "errors" directory).
6535 Wherever you want the 'err_html_text' line to appear,
6536 insert a %L tag in the error template file.
6539 NAME: email_err_data
6542 LOC: Config.onoff.emailErrData
6545 If enabled, information about the occurred error will be
6546 included in the mailto links of the ERR pages (if %W is set)
6547 so that the email body contains the data.
6548 Syntax is <A HREF="mailto:%w%W">%w</A>
6553 LOC: Config.denyInfoList
6556 Usage: deny_info err_page_name acl
6557 or deny_info http://... acl
6558 or deny_info TCP_RESET acl
6560 This can be used to return a ERR_ page for requests which
6561 do not pass the 'http_access' rules. Squid remembers the last
6562 acl it evaluated in http_access, and if a 'deny_info' line exists
6563 for that ACL Squid returns a corresponding error page.
6565 The acl is typically the last acl on the http_access deny line which
6566 denied access. The exceptions to this rule are:
6567 - When Squid needs to request authentication credentials. It's then
6568 the first authentication related acl encountered
6569 - When none of the http_access lines matches. It's then the last
6570 acl processed on the last http_access line.
6571 - When the decision to deny access was made by an adaptation service,
6572 the acl name is the corresponding eCAP or ICAP service_name.
6574 NP: If providing your own custom error pages with error_directory
6575 you may also specify them by your custom file name:
6576 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
6578 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
6579 may be specified by prefixing the file name with the code and a colon.
6580 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
6582 Alternatively you can tell Squid to reset the TCP connection
6583 by specifying TCP_RESET.
6585 Or you can specify an error URL or URL pattern. The browsers will
6586 get redirected to the specified URL after formatting tags have
6587 been replaced. Redirect will be done with 302 or 307 according to
6588 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
6589 the URL. e.g. 303:http://example.com/
6592 %a - username (if available. Password NOT included)
6595 %E - Error description
6597 %H - Request domain name
6598 %i - Client IP Address
6600 %o - Message result from external ACL helper
6601 %p - Request Port number
6602 %P - Request Protocol name
6603 %R - Request URL path
6604 %T - Timestamp in RFC 1123 format
6605 %U - Full canonical URL from client
6606 (HTTPS URLs terminate with *)
6607 %u - Full canonical URL from client
6608 %w - Admin email from squid.conf
6610 %% - Literal percent (%) code
6615 OPTIONS INFLUENCING REQUEST FORWARDING
6616 -----------------------------------------------------------------------------
6619 NAME: nonhierarchical_direct
6621 LOC: Config.onoff.nonhierarchical_direct
6624 By default, Squid will send any non-hierarchical requests
6625 (matching hierarchy_stoplist or not cacheable request type) direct
6628 If you set this to off, Squid will prefer to send these
6629 requests to parents.
6631 Note that in most configurations, by turning this off you will only
6632 add latency to these request without any improvement in global hit
6635 If you are inside an firewall see never_direct instead of
6641 LOC: Config.onoff.prefer_direct
6644 Normally Squid tries to use parents for most requests. If you for some
6645 reason like it to first try going direct and only use a parent if
6646 going direct fails set this to on.
6648 By combining nonhierarchical_direct off and prefer_direct on you
6649 can set up Squid to use a parent as a backup path if going direct
6652 Note: If you want Squid to use parents for all requests see
6653 the never_direct directive. prefer_direct only modifies how Squid
6654 acts on cacheable requests.
6659 LOC: Config.accessList.AlwaysDirect
6662 Usage: always_direct allow|deny [!]aclname ...
6664 Here you can use ACL elements to specify requests which should
6665 ALWAYS be forwarded by Squid to the origin servers without using
6666 any peers. For example, to always directly forward requests for
6667 local servers ignoring any parents or siblings you may have use
6670 acl local-servers dstdomain my.domain.net
6671 always_direct allow local-servers
6673 To always forward FTP requests directly, use
6676 always_direct allow FTP
6678 NOTE: There is a similar, but opposite option named
6679 'never_direct'. You need to be aware that "always_direct deny
6680 foo" is NOT the same thing as "never_direct allow foo". You
6681 may need to use a deny rule to exclude a more-specific case of
6682 some other rule. Example:
6684 acl local-external dstdomain external.foo.net
6685 acl local-servers dstdomain .foo.net
6686 always_direct deny local-external
6687 always_direct allow local-servers
6689 NOTE: If your goal is to make the client forward the request
6690 directly to the origin server bypassing Squid then this needs
6691 to be done in the client configuration. Squid configuration
6692 can only tell Squid how Squid should fetch the object.
6694 NOTE: This directive is not related to caching. The replies
6695 is cached as usual even if you use always_direct. To not cache
6696 the replies see the 'cache' directive.
6698 This clause supports both fast and slow acl types.
6699 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6704 LOC: Config.accessList.NeverDirect
6707 Usage: never_direct allow|deny [!]aclname ...
6709 never_direct is the opposite of always_direct. Please read
6710 the description for always_direct if you have not already.
6712 With 'never_direct' you can use ACL elements to specify
6713 requests which should NEVER be forwarded directly to origin
6714 servers. For example, to force the use of a proxy for all
6715 requests, except those in your local domain use something like:
6717 acl local-servers dstdomain .foo.net
6718 never_direct deny local-servers
6719 never_direct allow all
6721 or if Squid is inside a firewall and there are local intranet
6722 servers inside the firewall use something like:
6724 acl local-intranet dstdomain .foo.net
6725 acl local-external dstdomain external.foo.net
6726 always_direct deny local-external
6727 always_direct allow local-intranet
6728 never_direct allow all
6730 This clause supports both fast and slow acl types.
6731 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6735 ADVANCED NETWORKING OPTIONS
6736 -----------------------------------------------------------------------------
6739 NAME: incoming_udp_average incoming_icp_average
6742 LOC: Config.comm_incoming.udp.average
6744 Heavy voodoo here. I can't even believe you are reading this.
6745 Are you crazy? Don't even think about adjusting these unless
6746 you understand the algorithms in comm_select.c first!
6749 NAME: incoming_tcp_average incoming_http_average
6752 LOC: Config.comm_incoming.tcp.average
6754 Heavy voodoo here. I can't even believe you are reading this.
6755 Are you crazy? Don't even think about adjusting these unless
6756 you understand the algorithms in comm_select.c first!
6759 NAME: incoming_dns_average
6762 LOC: Config.comm_incoming.dns.average
6764 Heavy voodoo here. I can't even believe you are reading this.
6765 Are you crazy? Don't even think about adjusting these unless
6766 you understand the algorithms in comm_select.c first!
6769 NAME: min_udp_poll_cnt min_icp_poll_cnt
6772 LOC: Config.comm_incoming.udp.min_poll
6774 Heavy voodoo here. I can't even believe you are reading this.
6775 Are you crazy? Don't even think about adjusting these unless
6776 you understand the algorithms in comm_select.c first!
6779 NAME: min_dns_poll_cnt
6782 LOC: Config.comm_incoming.dns.min_poll
6784 Heavy voodoo here. I can't even believe you are reading this.
6785 Are you crazy? Don't even think about adjusting these unless
6786 you understand the algorithms in comm_select.c first!
6789 NAME: min_tcp_poll_cnt min_http_poll_cnt
6792 LOC: Config.comm_incoming.tcp.min_poll
6794 Heavy voodoo here. I can't even believe you are reading this.
6795 Are you crazy? Don't even think about adjusting these unless
6796 you understand the algorithms in comm_select.c first!
6802 LOC: Config.accept_filter
6806 The name of an accept(2) filter to install on Squid's
6807 listen socket(s). This feature is perhaps specific to
6808 FreeBSD and requires support in the kernel.
6810 The 'httpready' filter delays delivering new connections
6811 to Squid until a full HTTP request has been received.
6812 See the accf_http(9) man page for details.
6814 The 'dataready' filter delays delivering new connections
6815 to Squid until there is some data to process.
6816 See the accf_dataready(9) man page for details.
6820 The 'data' filter delays delivering of new connections
6821 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
6822 You may optionally specify a number of seconds to wait by
6823 'data=N' where N is the number of seconds. Defaults to 30
6824 if not specified. See the tcp(7) man page for details.
6827 accept_filter httpready
6832 NAME: client_ip_max_connections
6834 LOC: Config.client_ip_max_connections
6837 Set an absolute limit on the number of connections a single
6838 client IP can use. Any more than this and Squid will begin to drop
6839 new connections from the client until it closes some links.
6841 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
6842 connections from the client. For finer control use the ACL access controls.
6844 Requires client_db to be enabled (the default).
6846 WARNING: This may noticably slow down traffic received via external proxies
6847 or NAT devices and cause them to rebound error messages back to their clients.
6850 NAME: tcp_recv_bufsize
6854 LOC: Config.tcpRcvBufsz
6856 Size of receive buffer to set for TCP sockets. Probably just
6857 as easy to change your kernel's default. Set to zero to use
6858 the default buffer size.
6863 -----------------------------------------------------------------------------
6870 LOC: Adaptation::Icap::TheConfig.onoff
6873 If you want to enable the ICAP module support, set this to on.
6876 NAME: icap_connect_timeout
6879 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
6882 This parameter specifies how long to wait for the TCP connect to
6883 the requested ICAP server to complete before giving up and either
6884 terminating the HTTP transaction or bypassing the failure.
6886 The default for optional services is peer_connect_timeout.
6887 The default for essential services is connect_timeout.
6888 If this option is explicitly set, its value applies to all services.
6891 NAME: icap_io_timeout
6895 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
6898 This parameter specifies how long to wait for an I/O activity on
6899 an established, active ICAP connection before giving up and
6900 either terminating the HTTP transaction or bypassing the
6903 The default is read_timeout.
6906 NAME: icap_service_failure_limit
6907 COMMENT: limit [in memory-depth time-units]
6908 TYPE: icap_service_failure_limit
6910 LOC: Adaptation::Icap::TheConfig
6913 The limit specifies the number of failures that Squid tolerates
6914 when establishing a new TCP connection with an ICAP service. If
6915 the number of failures exceeds the limit, the ICAP service is
6916 not used for new ICAP requests until it is time to refresh its
6919 A negative value disables the limit. Without the limit, an ICAP
6920 service will not be considered down due to connectivity failures
6921 between ICAP OPTIONS requests.
6923 Squid forgets ICAP service failures older than the specified
6924 value of memory-depth. The memory fading algorithm
6925 is approximate because Squid does not remember individual
6926 errors but groups them instead, splitting the option
6927 value into ten time slots of equal length.
6929 When memory-depth is 0 and by default this option has no
6930 effect on service failure expiration.
6932 Squid always forgets failures when updating service settings
6933 using an ICAP OPTIONS transaction, regardless of this option
6937 # suspend service usage after 10 failures in 5 seconds:
6938 icap_service_failure_limit 10 in 5 seconds
6941 NAME: icap_service_revival_delay
6944 LOC: Adaptation::Icap::TheConfig.service_revival_delay
6947 The delay specifies the number of seconds to wait after an ICAP
6948 OPTIONS request failure before requesting the options again. The
6949 failed ICAP service is considered "down" until fresh OPTIONS are
6952 The actual delay cannot be smaller than the hardcoded minimum
6953 delay of 30 seconds.
6956 NAME: icap_preview_enable
6960 LOC: Adaptation::Icap::TheConfig.preview_enable
6963 The ICAP Preview feature allows the ICAP server to handle the
6964 HTTP message by looking only at the beginning of the message body
6965 or even without receiving the body at all. In some environments,
6966 previews greatly speedup ICAP processing.
6968 During an ICAP OPTIONS transaction, the server may tell Squid what
6969 HTTP messages should be previewed and how big the preview should be.
6970 Squid will not use Preview if the server did not request one.
6972 To disable ICAP Preview for all ICAP services, regardless of
6973 individual ICAP server OPTIONS responses, set this option to "off".
6975 icap_preview_enable off
6978 NAME: icap_preview_size
6981 LOC: Adaptation::Icap::TheConfig.preview_size
6984 The default size of preview data to be sent to the ICAP server.
6985 -1 means no preview. This value might be overwritten on a per server
6986 basis by OPTIONS requests.
6989 NAME: icap_206_enable
6993 LOC: Adaptation::Icap::TheConfig.allow206_enable
6996 206 (Partial Content) responses is an ICAP extension that allows the
6997 ICAP agents to optionally combine adapted and original HTTP message
6998 content. The decision to combine is postponed until the end of the
6999 ICAP response. Squid supports Partial Content extension by default.
7001 Activation of the Partial Content extension is negotiated with each
7002 ICAP service during OPTIONS exchange. Most ICAP servers should handle
7003 negotation correctly even if they do not support the extension, but
7004 some might fail. To disable Partial Content support for all ICAP
7005 services and to avoid any negotiation, set this option to "off".
7011 NAME: icap_default_options_ttl
7014 LOC: Adaptation::Icap::TheConfig.default_options_ttl
7017 The default TTL value for ICAP OPTIONS responses that don't have
7018 an Options-TTL header.
7021 NAME: icap_persistent_connections
7025 LOC: Adaptation::Icap::TheConfig.reuse_connections
7028 Whether or not Squid should use persistent connections to
7032 NAME: adaptation_send_client_ip icap_send_client_ip
7034 IFDEF: USE_ADAPTATION
7036 LOC: Adaptation::Config::send_client_ip
7039 If enabled, Squid shares HTTP client IP information with adaptation
7040 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
7041 For eCAP, Squid sets the libecap::metaClientIp transaction option.
7043 See also: adaptation_uses_indirect_client
7046 NAME: adaptation_send_username icap_send_client_username
7048 IFDEF: USE_ADAPTATION
7050 LOC: Adaptation::Config::send_username
7053 This sends authenticated HTTP client username (if available) to
7054 the adaptation service.
7056 For ICAP, the username value is encoded based on the
7057 icap_client_username_encode option and is sent using the header
7058 specified by the icap_client_username_header option.
7061 NAME: icap_client_username_header
7064 LOC: Adaptation::Icap::TheConfig.client_username_header
7065 DEFAULT: X-Client-Username
7067 ICAP request header name to use for adaptation_send_username.
7070 NAME: icap_client_username_encode
7074 LOC: Adaptation::Icap::TheConfig.client_username_encode
7077 Whether to base64 encode the authenticated client username.
7081 TYPE: icap_service_type
7083 LOC: Adaptation::Icap::TheConfig
7086 Defines a single ICAP service using the following format:
7088 icap_service id vectoring_point uri [option ...]
7091 an opaque identifier or name which is used to direct traffic to
7092 this specific service. Must be unique among all adaptation
7093 services in squid.conf.
7095 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7096 This specifies at which point of transaction processing the
7097 ICAP service should be activated. *_postcache vectoring points
7098 are not yet supported.
7100 uri: icap://servername:port/servicepath
7101 ICAP server and service location.
7103 ICAP does not allow a single service to handle both REQMOD and RESPMOD
7104 transactions. Squid does not enforce that requirement. You can specify
7105 services with the same service_url and different vectoring_points. You
7106 can even specify multiple identical services as long as their
7107 service_names differ.
7110 Service options are separated by white space. ICAP services support
7111 the following name=value options:
7114 If set to 'on' or '1', the ICAP service is treated as
7115 optional. If the service cannot be reached or malfunctions,
7116 Squid will try to ignore any errors and process the message as
7117 if the service was not enabled. No all ICAP errors can be
7118 bypassed. If set to 0, the ICAP service is treated as
7119 essential and all ICAP errors will result in an error page
7120 returned to the HTTP client.
7122 Bypass is off by default: services are treated as essential.
7125 If set to 'on' or '1', the ICAP service is allowed to
7126 dynamically change the current message adaptation plan by
7127 returning a chain of services to be used next. The services
7128 are specified using the X-Next-Services ICAP response header
7129 value, formatted as a comma-separated list of service names.
7130 Each named service should be configured in squid.conf. Other
7131 services are ignored. An empty X-Next-Services value results
7132 in an empty plan which ends the current adaptation.
7134 Dynamic adaptation plan may cross or cover multiple supported
7135 vectoring points in their natural processing order.
7137 Routing is not allowed by default: the ICAP X-Next-Services
7138 response header is ignored.
7141 Only has effect on split-stack systems. The default on those systems
7142 is to use IPv4-only connections. When set to 'on' this option will
7143 make Squid use IPv6-only connections to contact this ICAP service.
7145 on-overload=block|bypass|wait|force
7146 If the service Max-Connections limit has been reached, do
7147 one of the following for each new ICAP transaction:
7148 * block: send an HTTP error response to the client
7149 * bypass: ignore the "over-connected" ICAP service
7150 * wait: wait (in a FIFO queue) for an ICAP connection slot
7151 * force: proceed, ignoring the Max-Connections limit
7153 In SMP mode with N workers, each worker assumes the service
7154 connection limit is Max-Connections/N, even though not all
7155 workers may use a given service.
7157 The default value is "bypass" if service is bypassable,
7158 otherwise it is set to "wait".
7162 Use the given number as the Max-Connections limit, regardless
7163 of the Max-Connections value given by the service, if any.
7165 Older icap_service format without optional named parameters is
7166 deprecated but supported for backward compatibility.
7169 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
7170 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
7174 TYPE: icap_class_type
7179 This deprecated option was documented to define an ICAP service
7180 chain, even though it actually defined a set of similar, redundant
7181 services, and the chains were not supported.
7183 To define a set of redundant services, please use the
7184 adaptation_service_set directive. For service chains, use
7185 adaptation_service_chain.
7189 TYPE: icap_access_type
7194 This option is deprecated. Please use adaptation_access, which
7195 has the same ICAP functionality, but comes with better
7196 documentation, and eCAP support.
7201 -----------------------------------------------------------------------------
7208 LOC: Adaptation::Ecap::TheConfig.onoff
7211 Controls whether eCAP support is enabled.
7215 TYPE: ecap_service_type
7217 LOC: Adaptation::Ecap::TheConfig
7220 Defines a single eCAP service
7222 ecap_service id vectoring_point uri [option ...]
7225 an opaque identifier or name which is used to direct traffic to
7226 this specific service. Must be unique among all adaptation
7227 services in squid.conf.
7229 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7230 This specifies at which point of transaction processing the
7231 eCAP service should be activated. *_postcache vectoring points
7232 are not yet supported.
7234 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
7235 Squid uses the eCAP service URI to match this configuration
7236 line with one of the dynamically loaded services. Each loaded
7237 eCAP service must have a unique URI. Obtain the right URI from
7238 the service provider.
7241 Service options are separated by white space. eCAP services support
7242 the following name=value options:
7245 If set to 'on' or '1', the eCAP service is treated as optional.
7246 If the service cannot be reached or malfunctions, Squid will try
7247 to ignore any errors and process the message as if the service
7248 was not enabled. No all eCAP errors can be bypassed.
7249 If set to 'off' or '0', the eCAP service is treated as essential
7250 and all eCAP errors will result in an error page returned to the
7253 Bypass is off by default: services are treated as essential.
7256 If set to 'on' or '1', the eCAP service is allowed to
7257 dynamically change the current message adaptation plan by
7258 returning a chain of services to be used next.
7260 Dynamic adaptation plan may cross or cover multiple supported
7261 vectoring points in their natural processing order.
7263 Routing is not allowed by default.
7265 Older ecap_service format without optional named parameters is
7266 deprecated but supported for backward compatibility.
7270 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
7271 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
7274 NAME: loadable_modules
7276 IFDEF: USE_LOADABLE_MODULES
7277 LOC: Config.loadable_module_names
7280 Instructs Squid to load the specified dynamic module(s) or activate
7281 preloaded module(s).
7283 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
7287 MESSAGE ADAPTATION OPTIONS
7288 -----------------------------------------------------------------------------
7291 NAME: adaptation_service_set
7292 TYPE: adaptation_service_set_type
7293 IFDEF: USE_ADAPTATION
7298 Configures an ordered set of similar, redundant services. This is
7299 useful when hot standby or backup adaptation servers are available.
7301 adaptation_service_set set_name service_name1 service_name2 ...
7303 The named services are used in the set declaration order. The first
7304 applicable adaptation service from the set is used first. The next
7305 applicable service is tried if and only if the transaction with the
7306 previous service fails and the message waiting to be adapted is still
7309 When adaptation starts, broken services are ignored as if they were
7310 not a part of the set. A broken service is a down optional service.
7312 The services in a set must be attached to the same vectoring point
7313 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7315 If all services in a set are optional then adaptation failures are
7316 bypassable. If all services in the set are essential, then a
7317 transaction failure with one service may still be retried using
7318 another service from the set, but when all services fail, the master
7319 transaction fails as well.
7321 A set may contain a mix of optional and essential services, but that
7322 is likely to lead to surprising results because broken services become
7323 ignored (see above), making previously bypassable failures fatal.
7324 Technically, it is the bypassability of the last failed service that
7327 See also: adaptation_access adaptation_service_chain
7330 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
7331 adaptation service_set svcLogger loggerLocal loggerRemote
7334 NAME: adaptation_service_chain
7335 TYPE: adaptation_service_chain_type
7336 IFDEF: USE_ADAPTATION
7341 Configures a list of complementary services that will be applied
7342 one-by-one, forming an adaptation chain or pipeline. This is useful
7343 when Squid must perform different adaptations on the same message.
7345 adaptation_service_chain chain_name service_name1 svc_name2 ...
7347 The named services are used in the chain declaration order. The first
7348 applicable adaptation service from the chain is used first. The next
7349 applicable service is applied to the successful adaptation results of
7350 the previous service in the chain.
7352 When adaptation starts, broken services are ignored as if they were
7353 not a part of the chain. A broken service is a down optional service.
7355 Request satisfaction terminates the adaptation chain because Squid
7356 does not currently allow declaration of RESPMOD services at the
7357 "reqmod_precache" vectoring point (see icap_service or ecap_service).
7359 The services in a chain must be attached to the same vectoring point
7360 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7362 A chain may contain a mix of optional and essential services. If an
7363 essential adaptation fails (or the failure cannot be bypassed for
7364 other reasons), the master transaction fails. Otherwise, the failure
7365 is bypassed as if the failed adaptation service was not in the chain.
7367 See also: adaptation_access adaptation_service_set
7370 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
7373 NAME: adaptation_access
7374 TYPE: adaptation_access_type
7375 IFDEF: USE_ADAPTATION
7379 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
7381 adaptation_access service_name allow|deny [!]aclname...
7382 adaptation_access set_name allow|deny [!]aclname...
7384 At each supported vectoring point, the adaptation_access
7385 statements are processed in the order they appear in this
7386 configuration file. Statements pointing to the following services
7387 are ignored (i.e., skipped without checking their ACL):
7389 - services serving different vectoring points
7390 - "broken-but-bypassable" services
7391 - "up" services configured to ignore such transactions
7392 (e.g., based on the ICAP Transfer-Ignore header).
7394 When a set_name is used, all services in the set are checked
7395 using the same rules, to find the first applicable one. See
7396 adaptation_service_set for details.
7398 If an access list is checked and there is a match, the
7399 processing stops: For an "allow" rule, the corresponding
7400 adaptation service is used for the transaction. For a "deny"
7401 rule, no adaptation service is activated.
7403 It is currently not possible to apply more than one adaptation
7404 service at the same vectoring point to the same HTTP transaction.
7406 See also: icap_service and ecap_service
7409 adaptation_access service_1 allow all
7412 NAME: adaptation_service_iteration_limit
7414 IFDEF: USE_ADAPTATION
7415 LOC: Adaptation::Config::service_iteration_limit
7418 Limits the number of iterations allowed when applying adaptation
7419 services to a message. If your longest adaptation set or chain
7420 may have more than 16 services, increase the limit beyond its
7421 default value of 16. If detecting infinite iteration loops sooner
7422 is critical, make the iteration limit match the actual number
7423 of services in your longest adaptation set or chain.
7425 Infinite adaptation loops are most likely with routing services.
7427 See also: icap_service routing=1
7430 NAME: adaptation_masterx_shared_names
7432 IFDEF: USE_ADAPTATION
7433 LOC: Adaptation::Config::masterx_shared_name
7436 For each master transaction (i.e., the HTTP request and response
7437 sequence, including all related ICAP and eCAP exchanges), Squid
7438 maintains a table of metadata. The table entries are (name, value)
7439 pairs shared among eCAP and ICAP exchanges. The table is destroyed
7440 with the master transaction.
7442 This option specifies the table entry names that Squid must accept
7443 from and forward to the adaptation transactions.
7445 An ICAP REQMOD or RESPMOD transaction may set an entry in the
7446 shared table by returning an ICAP header field with a name
7447 specified in adaptation_masterx_shared_names.
7449 An eCAP REQMOD or RESPMOD transaction may set an entry in the
7450 shared table by implementing the libecap::visitEachOption() API
7451 to provide an option with a name specified in
7452 adaptation_masterx_shared_names.
7454 Squid will store and forward the set entry to subsequent adaptation
7455 transactions within the same master transaction scope.
7457 Only one shared entry name is supported at this time.
7460 # share authentication information among ICAP services
7461 adaptation_masterx_shared_names X-Subscriber-ID
7464 NAME: adaptation_meta
7466 IFDEF: USE_ADAPTATION
7467 LOC: Adaptation::Config::metaHeaders
7470 This option allows Squid administrator to add custom ICAP request
7471 headers or eCAP options to Squid ICAP requests or eCAP transactions.
7472 Use it to pass custom authentication tokens and other
7473 transaction-state related meta information to an ICAP/eCAP service.
7475 The addition of a meta header is ACL-driven:
7476 adaptation_meta name value [!]aclname ...
7478 Processing for a given header name stops after the first ACL list match.
7479 Thus, it is impossible to add two headers with the same name. If no ACL
7480 lists match for a given header name, no such header is added. For
7483 # do not debug transactions except for those that need debugging
7484 adaptation_meta X-Debug 1 needs_debugging
7486 # log all transactions except for those that must remain secret
7487 adaptation_meta X-Log 1 !keep_secret
7489 # mark transactions from users in the "G 1" group
7490 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
7492 The "value" parameter may be a regular squid.conf token or a "double
7493 quoted string". Within the quoted string, use backslash (\) to escape
7494 any character, which is currently only useful for escaping backslashes
7495 and double quotes. For example,
7496 "this string has one backslash (\\) and two \"quotes\""
7498 Used adaptation_meta header values may be logged via %note
7499 logformat code. If multiple adaptation_meta headers with the same name
7500 are used during master transaction lifetime, the header values are
7501 logged in the order they were used and duplicate values are ignored
7502 (only the first repeated value will be logged).
7508 LOC: Adaptation::Icap::TheConfig.repeat
7509 DEFAULT_IF_NONE: deny all
7511 This ACL determines which retriable ICAP transactions are
7512 retried. Transactions that received a complete ICAP response
7513 and did not have to consume or produce HTTP bodies to receive
7514 that response are usually retriable.
7516 icap_retry allow|deny [!]aclname ...
7518 Squid automatically retries some ICAP I/O timeouts and errors
7519 due to persistent connection race conditions.
7521 See also: icap_retry_limit
7524 NAME: icap_retry_limit
7527 LOC: Adaptation::Icap::TheConfig.repeat_limit
7530 Limits the number of retries allowed. When set to zero (default),
7531 no retries are allowed.
7533 Communication errors due to persistent connection race
7534 conditions are unavoidable, automatically retried, and do not
7535 count against this limit.
7537 See also: icap_retry
7543 -----------------------------------------------------------------------------
7546 NAME: check_hostnames
7549 LOC: Config.onoff.check_hostnames
7551 For security and stability reasons Squid can check
7552 hostnames for Internet standard RFC compliance. If you want
7553 Squid to perform these checks turn this directive on.
7556 NAME: allow_underscore
7559 LOC: Config.onoff.allow_underscore
7561 Underscore characters is not strictly allowed in Internet hostnames
7562 but nevertheless used by many sites. Set this to off if you want
7563 Squid to be strict about the standard.
7564 This check is performed only when check_hostnames is set to on.
7567 NAME: cache_dns_program
7569 IFDEF: USE_DNSHELPER
7570 DEFAULT: @DEFAULT_DNSSERVER@
7571 LOC: Config.Program.dnsserver
7573 Specify the location of the executable for dnslookup process.
7577 TYPE: HelperChildConfig
7578 IFDEF: USE_DNSHELPER
7579 DEFAULT: 32 startup=1 idle=1
7580 LOC: Config.dnsChildren
7582 The maximum number of processes spawn to service DNS name lookups.
7583 If you limit it too few Squid will have to wait for them to process
7584 a backlog of requests, slowing it down. If you allow too many they
7585 will use RAM and other system resources noticably.
7586 The maximum this may be safely set to is 32.
7588 The startup= and idle= options allow some measure of skew in your
7593 Sets a minimum of how many processes are to be spawned when Squid
7594 starts or reconfigures. When set to zero the first request will
7595 cause spawning of the first child process to handle it.
7597 Starting too few will cause an initial slowdown in traffic as Squid
7598 attempts to simultaneously spawn enough processes to cope.
7602 Sets a minimum of how many processes Squid is to try and keep available
7603 at all times. When traffic begins to rise above what the existing
7604 processes can handle this many more will be spawned up to the maximum
7605 configured. A minimum setting of 1 is required.
7608 NAME: dns_retransmit_interval
7611 LOC: Config.Timeout.idns_retransmit
7612 IFDEF: !USE_DNSHELPER
7614 Initial retransmit interval for DNS queries. The interval is
7615 doubled each time all configured DNS servers have been tried.
7621 LOC: Config.Timeout.idns_query
7622 IFDEF: !USE_DNSHELPER
7624 DNS Query timeout. If no response is received to a DNS query
7625 within this time all DNS servers for the queried domain
7626 are assumed to be unavailable.
7629 NAME: dns_packet_max
7632 LOC: Config.dns.packet_max
7633 IFDEF: !USE_DNSHELPER
7635 Maximum number of bytes packet size to advertise via EDNS.
7636 Set to "none" to disable EDNS large packet support.
7638 For legacy reasons DNS UDP replies will default to 512 bytes which
7639 is too small for many responses. EDNS provides a means for Squid to
7640 negotiate receiving larger responses back immediately without having
7641 to failover with repeat requests. Responses larger than this limit
7642 will retain the old behaviour of failover to TCP DNS.
7644 Squid has no real fixed limit internally, but allowing packet sizes
7645 over 1500 bytes requires network jumbogram support and is usually not
7648 WARNING: The RFC also indicates that some older resolvers will reply
7649 with failure of the whole request if the extension is added. Some
7650 resolvers have already been identified which will reply with mangled
7651 EDNS response on occasion. Usually in response to many-KB jumbogram
7652 sizes being advertised by Squid.
7653 Squid will currently treat these both as an unable-to-resolve domain
7654 even if it would be resolvable without EDNS.
7661 LOC: Config.onoff.res_defnames
7663 Normally the RES_DEFNAMES resolver option is disabled
7664 (see res_init(3)). This prevents caches in a hierarchy
7665 from interpreting single-component hostnames locally. To allow
7666 Squid to handle single-component names, enable this option.
7669 NAME: dns_nameservers
7672 LOC: Config.dns_nameservers
7674 Use this if you want to specify a list of DNS name servers
7675 (IP addresses) to use instead of those given in your
7676 /etc/resolv.conf file.
7677 On Windows platforms, if no value is specified here or in
7678 the /etc/resolv.conf file, the list of DNS name servers are
7679 taken from the Windows registry, both static and dynamic DHCP
7680 configurations are supported.
7682 Example: dns_nameservers 10.0.0.1 192.172.0.4
7687 DEFAULT: @DEFAULT_HOSTS@
7688 LOC: Config.etcHostsPath
7690 Location of the host-local IP name-address associations
7691 database. Most Operating Systems have such a file on different
7693 - Un*X & Linux: /etc/hosts
7694 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
7695 (%SystemRoot% value install default is c:\winnt)
7696 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
7697 (%SystemRoot% value install default is c:\windows)
7698 - Windows 9x/Me: %windir%\hosts
7699 (%windir% value is usually c:\windows)
7700 - Cygwin: /etc/hosts
7702 The file contains newline-separated definitions, in the
7703 form ip_address_in_dotted_form name [name ...] names are
7704 whitespace-separated. Lines beginning with an hash (#)
7705 character are comments.
7707 The file is checked at startup and upon configuration.
7708 If set to 'none', it won't be checked.
7709 If append_domain is used, that domain will be added to
7710 domain-local (i.e. not containing any dot character) host
7716 LOC: Config.appendDomain
7719 Appends local domain name to hostnames without any dots in
7720 them. append_domain must begin with a period.
7722 Be warned there are now Internet names with no dots in
7723 them using only top-domain names, so setting this may
7724 cause some Internet sites to become unavailable.
7727 append_domain .yourdomain.com
7730 NAME: ignore_unknown_nameservers
7732 LOC: Config.onoff.ignore_unknown_nameservers
7734 IFDEF: !USE_DNSHELPER
7736 By default Squid checks that DNS responses are received
7737 from the same IP addresses they are sent to. If they
7738 don't match, Squid ignores the response and writes a warning
7739 message to cache.log. You can allow responses from unknown
7740 nameservers by setting this option to 'off'.
7746 LOC: Config.dns.v4_first
7747 IFDEF: !USE_DNSHELPER
7749 With the IPv6 Internet being as fast or faster than IPv4 Internet
7750 for most networks Squid prefers to contact websites over IPv6.
7752 This option reverses the order of preference to make Squid contact
7753 dual-stack websites over IPv4 first. Squid will still perform both
7754 IPv6 and IPv4 DNS lookups before connecting.
7757 This option will restrict the situations under which IPv6
7758 connectivity is used (and tested). Hiding network problems
7759 which would otherwise be detected and warned about.
7763 COMMENT: (number of entries)
7766 LOC: Config.ipcache.size
7773 LOC: Config.ipcache.low
7780 LOC: Config.ipcache.high
7782 The size, low-, and high-water marks for the IP cache.
7785 NAME: fqdncache_size
7786 COMMENT: (number of entries)
7789 LOC: Config.fqdncache.size
7791 Maximum number of FQDN cache entries.
7796 -----------------------------------------------------------------------------
7803 LOC: Config.onoff.mem_pools
7805 If set, Squid will keep pools of allocated (but unused) memory
7806 available for future use. If memory is a premium on your
7807 system and you believe your malloc library outperforms Squid
7808 routines, disable this.
7811 NAME: memory_pools_limit
7815 LOC: Config.MemPools.limit
7817 Used only with memory_pools on:
7818 memory_pools_limit 50 MB
7820 If set to a non-zero value, Squid will keep at most the specified
7821 limit of allocated (but unused) memory in memory pools. All free()
7822 requests that exceed this limit will be handled by your malloc
7823 library. Squid does not pre-allocate any memory, just safe-keeps
7824 objects that otherwise would be free()d. Thus, it is safe to set
7825 memory_pools_limit to a reasonably high value even if your
7826 configuration will use less memory.
7828 If set to none, Squid will keep all memory it can. That is, there
7829 will be no limit on the total amount of memory used for safe-keeping.
7831 To disable memory allocation optimization, do not set
7832 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
7834 An overhead for maintaining memory pools is not taken into account
7835 when the limit is checked. This overhead is close to four bytes per
7836 object kept. However, pools may actually _save_ memory because of
7837 reduced memory thrashing in your malloc library.
7841 COMMENT: on|off|transparent|truncate|delete
7844 LOC: opt_forwarded_for
7846 If set to "on", Squid will append your client's IP address
7847 in the HTTP requests it forwards. By default it looks like:
7849 X-Forwarded-For: 192.1.2.3
7851 If set to "off", it will appear as
7853 X-Forwarded-For: unknown
7855 If set to "transparent", Squid will not alter the
7856 X-Forwarded-For header in any way.
7858 If set to "delete", Squid will delete the entire
7859 X-Forwarded-For header.
7861 If set to "truncate", Squid will remove all existing
7862 X-Forwarded-For entries, and place the client IP as the sole entry.
7865 NAME: cachemgr_passwd
7866 TYPE: cachemgrpasswd
7868 LOC: Config.passwd_list
7870 Specify passwords for cachemgr operations.
7872 Usage: cachemgr_passwd password action action ...
7874 Some valid actions are (see cache manager menu for a full list):
7914 * Indicates actions which will not be performed without a
7915 valid password, others can be performed if not listed here.
7917 To disable an action, set the password to "disable".
7918 To allow performing an action without a password, set the
7921 Use the keyword "all" to set the same password for all actions.
7924 cachemgr_passwd secret shutdown
7925 cachemgr_passwd lesssssssecret info stats/objects
7926 cachemgr_passwd disable all
7933 LOC: Config.onoff.client_db
7935 If you want to disable collecting per-client statistics,
7936 turn off client_db here.
7939 NAME: refresh_all_ims
7943 LOC: Config.onoff.refresh_all_ims
7945 When you enable this option, squid will always check
7946 the origin server for an update when a client sends an
7947 If-Modified-Since request. Many browsers use IMS
7948 requests when the user requests a reload, and this
7949 ensures those clients receive the latest version.
7951 By default (off), squid may return a Not Modified response
7952 based on the age of the cached version.
7955 NAME: reload_into_ims
7956 IFDEF: USE_HTTP_VIOLATIONS
7960 LOC: Config.onoff.reload_into_ims
7962 When you enable this option, client no-cache or ``reload''
7963 requests will be changed to If-Modified-Since requests.
7964 Doing this VIOLATES the HTTP standard. Enabling this
7965 feature could make you liable for problems which it
7968 see also refresh_pattern for a more selective approach.
7971 NAME: connect_retries
7973 LOC: Config.connect_retries
7976 This sets the maximum number of connection attempts made for each
7977 TCP connection. The connect_retries attempts must all still
7978 complete within the connection timeout period.
7980 The default is not to re-try if the first connection attempt fails.
7981 The (not recommended) maximum is 10 tries.
7983 A warning message will be generated if it is set to a too-high
7984 value and the configured value will be over-ridden.
7986 Note: These re-tries are in addition to forward_max_tries
7987 which limit how many different addresses may be tried to find
7991 NAME: retry_on_error
7993 LOC: Config.retry.onerror
7996 If set to ON Squid will automatically retry requests when
7997 receiving an error response with status 403 (Forbidden),
7998 500 (Internal Error), 501 or 503 (Service not available).
7999 Status 502 and 504 (Gateway errors) are always retried.
8001 This is mainly useful if you are in a complex cache hierarchy to
8002 work around access control errors.
8004 NOTE: This retry will attempt to find another working destination.
8005 Which is different from the server which just failed.
8008 NAME: as_whois_server
8010 LOC: Config.as_whois_server
8011 DEFAULT: whois.ra.net
8013 WHOIS server to query for AS numbers. NOTE: AS numbers are
8014 queried only when Squid starts up, not for every request.
8019 LOC: Config.onoff.offline
8022 Enable this option and Squid will never try to validate cached
8026 NAME: uri_whitespace
8027 TYPE: uri_whitespace
8028 LOC: Config.uri_whitespace
8031 What to do with requests that have whitespace characters in the
8034 strip: The whitespace characters are stripped out of the URL.
8035 This is the behavior recommended by RFC2396.
8036 deny: The request is denied. The user receives an "Invalid
8038 allow: The request is allowed and the URI is not changed. The
8039 whitespace characters remain in the URI. Note the
8040 whitespace is passed to redirector processes if they
8042 encode: The request is allowed and the whitespace characters are
8043 encoded according to RFC1738. This could be considered
8044 a violation of the HTTP/1.1
8045 RFC because proxies are not allowed to rewrite URI's.
8046 chop: The request is allowed and the URI is chopped at the
8047 first whitespace. This might also be considered a
8053 LOC: Config.chroot_dir
8056 Specifies a directory where Squid should do a chroot() while
8057 initializing. This also causes Squid to fully drop root
8058 privileges after initializing. This means, for example, if you
8059 use a HTTP port less than 1024 and try to reconfigure, you may
8060 get an error saying that Squid can not open the port.
8063 NAME: balance_on_multiple_ip
8065 LOC: Config.onoff.balance_on_multiple_ip
8068 Modern IP resolvers in squid sort lookup results by preferred access.
8069 By default squid will use these IP in order and only rotates to
8070 the next listed when the most preffered fails.
8072 Some load balancing servers based on round robin DNS have been
8073 found not to preserve user session state across requests
8074 to different IP addresses.
8076 Enabling this directive Squid rotates IP's per request.
8079 NAME: pipeline_prefetch
8081 LOC: Config.onoff.pipeline_prefetch
8084 To boost the performance of pipelined requests to closer
8085 match that of a non-proxied environment Squid can try to fetch
8086 up to two requests in parallel from a pipeline.
8088 Defaults to off for bandwidth management and access logging
8091 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
8094 NAME: high_response_time_warning
8097 LOC: Config.warnings.high_rptm
8100 If the one-minute median response time exceeds this value,
8101 Squid prints a WARNING with debug level 0 to get the
8102 administrators attention. The value is in milliseconds.
8105 NAME: high_page_fault_warning
8107 LOC: Config.warnings.high_pf
8110 If the one-minute average page fault rate exceeds this
8111 value, Squid prints a WARNING with debug level 0 to get
8112 the administrators attention. The value is in page faults
8116 NAME: high_memory_warning
8118 LOC: Config.warnings.high_memory
8121 If the memory usage (as determined by mallinfo) exceeds
8122 this amount, Squid prints a WARNING with debug level 0 to get
8123 the administrators attention.
8126 NAME: sleep_after_fork
8127 COMMENT: (microseconds)
8129 LOC: Config.sleep_after_fork
8132 When this is set to a non-zero value, the main Squid process
8133 sleeps the specified number of microseconds after a fork()
8134 system call. This sleep may help the situation where your
8135 system reports fork() failures due to lack of (virtual)
8136 memory. Note, however, if you have a lot of child
8137 processes, these sleep delays will add up and your
8138 Squid will not service requests for some amount of time
8139 until all the child processes have been started.
8140 On Windows value less then 1000 (1 milliseconds) are
8144 NAME: windows_ipaddrchangemonitor
8145 IFDEF: _SQUID_WINDOWS_
8149 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
8151 On Windows Squid by default will monitor IP address changes and will
8152 reconfigure itself after any detected event. This is very useful for
8153 proxies connected to internet with dial-up interfaces.
8154 In some cases (a Proxy server acting as VPN gateway is one) it could be
8155 desiderable to disable this behaviour setting this to 'off'.
8156 Note: after changing this, Squid service must be restarted.
8161 IFDEF: USE_SQUID_EUI
8163 LOC: Eui::TheConfig.euiLookup
8165 Whether to lookup the EUI or MAC address of a connected client.
8168 NAME: max_filedescriptors max_filedesc
8171 LOC: Config.max_filedescriptors
8173 The maximum number of filedescriptors supported.
8175 The default "0" means Squid inherits the current ulimit setting.
8177 Note: Changing this requires a restart of Squid. Also
8178 not all comm loops supports large values.
8186 Number of main Squid processes or "workers" to fork and maintain.
8187 0: "no daemon" mode, like running "squid -N ..."
8188 1: "no SMP" mode, start one main Squid process daemon (default)
8189 N: start N main Squid process daemons (i.e., SMP mode)
8191 In SMP mode, each worker does nearly all what a single Squid daemon
8192 does (e.g., listen on http_port and forward HTTP requests).
8195 NAME: cpu_affinity_map
8196 TYPE: CpuAffinityMap
8197 LOC: Config.cpuAffinityMap
8200 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
8202 Sets 1:1 mapping between Squid processes and CPU cores. For example,
8204 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
8206 affects processes 1 through 4 only and places them on the first
8207 four even cores, starting with core #1.
8209 CPU cores are numbered starting from 1. Requires support for
8210 sched_getaffinity(2) and sched_setaffinity(2) system calls.
8212 Multiple cpu_affinity_map options are merged.