2 # SQUID Web Proxy Cache http://www.squid-cache.org/
3 # ----------------------------------------------------------
5 # Squid is the result of efforts by numerous individuals from
6 # the Internet community; see the CONTRIBUTORS file for full
7 # details. Many organizations have provided support for Squid's
8 # development; see the SPONSORS file for full details. Squid is
9 # Copyrighted (C) 2000 by the Regents of the University of
10 # California; see the COPYRIGHT file for full details. Squid
11 # incorporates software developed and/or copyrighted by other
12 # sources; see the CREDITS file for full details.
14 # This program is free software; you can redistribute it and/or modify
15 # it under the terms of the GNU General Public License as published by
16 # the Free Software Foundation; either version 2 of the License, or
17 # (at your option) any later version.
19 # This program is distributed in the hope that it will be useful,
20 # but WITHOUT ANY WARRANTY; without even the implied warranty of
21 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 # GNU General Public License for more details.
24 # You should have received a copy of the GNU General Public License
25 # along with this program; if not, write to the Free Software
26 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
31 ----------------------------
33 This is the documentation for the Squid configuration file.
34 This documentation can also be found online at:
35 http://www.squid-cache.org/Doc/config/
37 You may wish to look at the Squid home page and wiki for the
38 FAQ and other documentation:
39 http://www.squid-cache.org/
40 http://wiki.squid-cache.org/SquidFaq
41 http://wiki.squid-cache.org/ConfigExamples
43 This documentation shows what the defaults for various directives
44 happen to be. If you don't need to change the default, you should
45 leave the line out of your squid.conf in most cases.
47 In some cases "none" refers to no default setting at all,
48 while in other cases it refers to the value of the option
49 - the comments for that keyword indicate if this is the case.
54 Configuration options can be included using the "include" directive.
55 Include takes a list of files to include. Quoting and wildcards are
60 include /path/to/included/file/squid.acl.config
62 Includes can be nested up to a hard-coded depth of 16 levels.
63 This arbitrary restriction is to prevent recursive include references
64 from causing Squid entering an infinite loop whilst trying to load
68 Conditional configuration
70 If-statements can be used to make configuration directives
74 ... regular configuration directives ...
76 ... regular configuration directives ...]
79 The else part is optional. The keywords "if", "else", and "endif"
80 must be typed on their own lines, as if they were regular
81 configuration directives.
83 NOTE: An else-if condition is not supported.
85 These individual conditions types are supported:
88 Always evaluates to true.
90 Always evaluates to false.
92 Equality comparison of two integer numbers.
97 The following SMP-related preprocessor macros can be used.
99 ${process_name} expands to the current Squid process "name"
100 (e.g., squid1, squid2, or cache1).
102 ${process_number} expands to the current Squid process
103 identifier, which is an integer number (e.g., 1, 2, 3) unique
104 across all Squid processes.
107 # Options Removed in 3.2
108 NAME: ignore_expect_100
111 Remove this line. The HTTP/1.1 feature is now fully supported by default.
114 NAME: dns_v4_fallback
123 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
126 NAME: maximum_single_addr_tries
129 Replaced by connect_retries. The behaviour has changed, please read the documentation before altering.
132 NAME: url_rewrite_concurrency
135 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
138 # Options Removed in 3.1
142 Remove this line. DNS is no longer tested on startup.
145 NAME: extension_methods
148 Remove this line. All valid methods for HTTP are accepted by default.
151 # 2.7 Options Removed/Replaced in 3.2
156 # 2.7 Options Removed/Replaced in 3.1
164 Remove this line. HTTP/1.1 is supported by default.
167 NAME: upgrade_http0.9
170 Remove this line. ICY/1.0 streaming protocol is supported by default.
173 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
176 Alter these entries. Use the qos_flows directive instead.
179 # Options Removed in 3.0
183 Since squid-3.0 replace with request_header_access or reply_header_access
184 depending on whether you wish to match client requests or server replies.
187 NAME: httpd_accel_no_pmtu_disc
190 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
194 OPTIONS FOR AUTHENTICATION
195 -----------------------------------------------------------------------------
204 This is used to define parameters for the various authentication
205 schemes supported by Squid.
207 format: auth_param scheme parameter [setting]
209 The order in which authentication schemes are presented to the client is
210 dependent on the order the scheme first appears in config file. IE
211 has a bug (it's not RFC 2617 compliant) in that it will use the basic
212 scheme if basic is the first entry presented, even if more secure
213 schemes are presented. For now use the order in the recommended
214 settings section below. If other browsers have difficulties (don't
215 recognize the schemes offered even if you are using basic) either
216 put basic first, or disable the other schemes (by commenting out their
219 Once an authentication scheme is fully configured, it can only be
220 shutdown by shutting squid down and restarting. Changes can be made on
221 the fly and activated with a reconfigure. I.E. You can change to a
222 different helper, but not unconfigure the helper completely.
224 Please note that while this directive defines how Squid processes
225 authentication it does not automatically activate authentication.
226 To use authentication you must in addition make use of ACLs based
227 on login name in http_access (proxy_auth, proxy_auth_regex or
228 external with %LOGIN used in the format tag). The browser will be
229 challenged for authentication on the first such acl encountered
230 in http_access processing and will also be re-challenged for new
231 login credentials if the request is being denied by a proxy_auth
234 WARNING: authentication can't be used in a transparently intercepting
235 proxy as the client then thinks it is talking to an origin server and
236 not the proxy. This is a limitation of bending the TCP/IP protocol to
237 transparently intercepting port 80, not a limitation in Squid.
238 Ports flagged 'transparent', 'intercept', or 'tproxy' have
239 authentication disabled.
241 === Parameters for the basic scheme follow. ===
244 Specify the command for the external authenticator. Such a program
245 reads a line containing "username password" and replies "OK" or
246 "ERR" in an endless loop. "ERR" responses may optionally be followed
247 by a error description available as %m in the returned error page.
248 If you use an authenticator, make sure you have 1 acl of type
251 By default, the basic authentication scheme is not used unless a
252 program is specified.
254 If you want to use the traditional NCSA proxy authentication, set
255 this line to something like
257 auth_param basic program @DEFAULT_PREFIX@/libexec/ncsa_auth @DEFAULT_PREFIX@/etc/passwd
260 HTTP uses iso-latin-1 as characterset, while some authentication
261 backends such as LDAP expects UTF-8. If this is set to on Squid will
262 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
263 username & password to the helper.
265 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
266 The maximum number of authenticator processes to spawn. If you start too few
267 Squid will have to wait for them to process a backlog of credential
268 verifications, slowing it down. When password verifications are
269 done via a (slow) network you are likely to need lots of
270 authenticator processes.
272 The startup= and idle= options permit some skew in the exact amount
273 run. A minimum of startup=N will begin during startup and reconfigure.
274 Squid will start more in groups of up to idle=N in an attempt to meet
275 traffic needs and to keep idle=N free above those traffic needs up to
278 The concurrency= option sets the number of concurrent requests the
279 helper can process. The default of 0 is used for helpers who only
280 supports one request at a time. Setting this to a number greater than
281 0 changes the protocol used to include a channel number first on the
282 request/response line, allowing multiple requests to be sent to the
283 same helper in parallell without wating for the response.
284 Must not be set unless it's known the helper supports this.
286 auth_param basic children 20 startup=0 idle=1
289 Specifies the realm name which is to be reported to the
290 client for the basic proxy authentication scheme (part of
291 the text the user will see when prompted their username and
292 password). There is no default.
293 auth_param basic realm Squid proxy-caching web server
295 "credentialsttl" timetolive
296 Specifies how long squid assumes an externally validated
297 username:password pair is valid for - in other words how
298 often the helper program is called for that user. Set this
299 low to force revalidation with short lived passwords. Note
300 setting this high does not impact your susceptibility
301 to replay attacks unless you are using an one-time password
302 system (such as SecureID). If you are using such a system,
303 you will be vulnerable to replay attacks unless you also
304 use the max_user_ip ACL in an http_access rule.
306 "casesensitive" on|off
307 Specifies if usernames are case sensitive. Most user databases are
308 case insensitive allowing the same username to be spelled using both
309 lower and upper case letters, but some are case sensitive. This
310 makes a big difference for user_max_ip ACL processing and similar.
311 auth_param basic casesensitive off
313 === Parameters for the digest scheme follow ===
316 Specify the command for the external authenticator. Such
317 a program reads a line containing "username":"realm" and
318 replies with the appropriate H(A1) value hex encoded or
319 ERR if the user (or his H(A1) hash) does not exists.
320 See rfc 2616 for the definition of H(A1).
321 "ERR" responses may optionally be followed by a error description
322 available as %m in the returned error page.
324 By default, the digest authentication scheme is not used unless a
325 program is specified.
327 If you want to use a digest authenticator, set this line to
330 auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass
333 HTTP uses iso-latin-1 as characterset, while some authentication
334 backends such as LDAP expects UTF-8. If this is set to on Squid will
335 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
336 username & password to the helper.
338 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
339 The maximum number of authenticator processes to spawn (default 5).
340 If you start too few Squid will have to wait for them to
341 process a backlog of H(A1) calculations, slowing it down.
342 When the H(A1) calculations are done via a (slow) network
343 you are likely to need lots of authenticator processes.
345 The startup= and idle= options permit some skew in the exact amount
346 run. A minimum of startup=N will begin during startup and reconfigure.
347 Squid will start more in groups of up to idle=N in an attempt to meet
348 traffic needs and to keep idle=N free above those traffic needs up to
351 The concurrency= option sets the number of concurrent requests the
352 helper can process. The default of 0 is used for helpers who only
353 supports one request at a time. Setting this to a number greater than
354 0 changes the protocol used to include a channel number first on the
355 request/response line, allowing multiple requests to be sent to the
356 same helper in parallell without wating for the response.
357 Must not be set unless it's known the helper supports this.
359 auth_param digest children 20 startup=0 idle=1
362 Specifies the realm name which is to be reported to the
363 client for the digest proxy authentication scheme (part of
364 the text the user will see when prompted their username and
365 password). There is no default.
366 auth_param digest realm Squid proxy-caching web server
368 "nonce_garbage_interval" timeinterval
369 Specifies the interval that nonces that have been issued
370 to client_agent's are checked for validity.
372 "nonce_max_duration" timeinterval
373 Specifies the maximum length of time a given nonce will be
376 "nonce_max_count" number
377 Specifies the maximum number of times a given nonce can be
380 "nonce_strictness" on|off
381 Determines if squid requires strict increment-by-1 behavior
382 for nonce counts, or just incrementing (off - for use when
383 useragents generate nonce counts that occasionally miss 1
384 (ie, 1,2,4,6)). Default off.
386 "check_nonce_count" on|off
387 This directive if set to off can disable the nonce count check
388 completely to work around buggy digest qop implementations in
389 certain mainstream browser versions. Default on to check the
390 nonce count to protect from authentication replay attacks.
392 "post_workaround" on|off
393 This is a workaround to certain buggy browsers who sends
394 an incorrect request digest in POST requests when reusing
395 the same nonce as acquired earlier on a GET request.
397 === NTLM scheme options follow ===
400 Specify the command for the external NTLM authenticator.
401 Such a program reads exchanged NTLMSSP packets with
402 the browser via Squid until authentication is completed.
403 If you use an NTLM authenticator, make sure you have 1 acl
404 of type proxy_auth. By default, the NTLM authenticator_program
407 auth_param ntlm program @DEFAULT_PREFIX@/bin/ntlm_auth
409 "children" numberofchildren [startup=N] [idle=N]
410 The maximum number of authenticator processes to spawn (default 5).
411 If you start too few Squid will have to wait for them to
412 process a backlog of credential verifications, slowing it
413 down. When credential verifications are done via a (slow)
414 network you are likely to need lots of authenticator
417 The startup= and idle= options permit some skew in the exact amount
418 run. A minimum of startup=N will begin during startup and reconfigure.
419 Squid will start more in groups of up to idle=N in an attempt to meet
420 traffic needs and to keep idle=N free above those traffic needs up to
423 auth_param ntlm children 20 startup=0 idle=1
426 If you experience problems with PUT/POST requests when using the
427 Negotiate authentication scheme then you can try setting this to
428 off. This will cause Squid to forcibly close the connection on
429 the initial requests where the browser asks which schemes are
430 supported by the proxy.
432 auth_param ntlm keep_alive on
434 === Options for configuring the NEGOTIATE auth-scheme follow ===
437 Specify the command for the external Negotiate authenticator.
438 This protocol is used in Microsoft Active-Directory enabled setups with
439 the Microsoft Internet Explorer or Mozilla Firefox browsers.
440 Its main purpose is to exchange credentials with the Squid proxy
441 using the Kerberos mechanisms.
442 If you use a Negotiate authenticator, make sure you have at least
443 one acl of type proxy_auth active. By default, the negotiate
444 authenticator_program is not used.
445 The only supported program for this role is the ntlm_auth
446 program distributed as part of Samba, version 4 or later.
448 auth_param negotiate program @DEFAULT_PREFIX@/bin/ntlm_auth --helper-protocol=gss-spnego
450 "children" numberofchildren [startup=N] [idle=N]
451 The maximum number of authenticator processes to spawn (default 5).
452 If you start too few Squid will have to wait for them to
453 process a backlog of credential verifications, slowing it
454 down. When crendential verifications are done via a (slow)
455 network you are likely to need lots of authenticator
458 The startup= and idle= options permit some skew in the exact amount
459 run. A minimum of startup=N will begin during startup and reconfigure.
460 Squid will start more in groups of up to idle=N in an attempt to meet
461 traffic needs and to keep idle=N free above those traffic needs up to
464 auth_param negotiate children 20 startup=0 idle=1
467 If you experience problems with PUT/POST requests when using the
468 Negotiate authentication scheme then you can try setting this to
469 off. This will cause Squid to forcibly close the connection on
470 the initial requests where the browser asks which schemes are
471 supported by the proxy.
473 auth_param negotiate keep_alive on
478 #Recommended minimum configuration per scheme:
479 #auth_param negotiate program <uncomment and complete this line to activate>
480 #auth_param negotiate children 20 startup=0 idle=1
481 #auth_param negotiate keep_alive on
483 #auth_param ntlm program <uncomment and complete this line to activate>
484 #auth_param ntlm children 20 startup=0 idle=1
485 #auth_param ntlm keep_alive on
487 #auth_param digest program <uncomment and complete this line>
488 #auth_param digest children 20 startup=0 idle=1
489 #auth_param digest realm Squid proxy-caching web server
490 #auth_param digest nonce_garbage_interval 5 minutes
491 #auth_param digest nonce_max_duration 30 minutes
492 #auth_param digest nonce_max_count 50
494 #auth_param basic program <uncomment and complete this line>
495 #auth_param basic children 5 startup=5 idle=1
496 #auth_param basic realm Squid proxy-caching web server
497 #auth_param basic credentialsttl 2 hours
500 NAME: authenticate_cache_garbage_interval
503 LOC: Config.authenticateGCInterval
505 The time period between garbage collection across the username cache.
506 This is a tradeoff between memory utilization (long intervals - say
507 2 days) and CPU (short intervals - say 1 minute). Only change if you
511 NAME: authenticate_ttl
514 LOC: Config.authenticateTTL
516 The time a user & their credentials stay in the logged in
517 user cache since their last request. When the garbage
518 interval passes, all user credentials that have passed their
519 TTL are removed from memory.
522 NAME: authenticate_ip_ttl
524 LOC: Config.authenticateIpTTL
527 If you use proxy authentication and the 'max_user_ip' ACL,
528 this directive controls how long Squid remembers the IP
529 addresses associated with each user. Use a small value
530 (e.g., 60 seconds) if your users might change addresses
531 quickly, as is the case with dialups. You might be safe
532 using a larger value (e.g., 2 hours) in a corporate LAN
533 environment with relatively static address assignments.
538 -----------------------------------------------------------------------------
541 NAME: external_acl_type
542 TYPE: externalAclHelper
543 LOC: Config.externalAclHelperList
546 This option defines external acl classes using a helper program
547 to look up the status
549 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
553 ttl=n TTL in seconds for cached results (defaults to 3600
556 TTL for cached negative lookups (default same
559 Maximum number of acl helper processes spawned to service
560 external acl lookups of this type. (default 20)
562 Minimum number of acl helper processes to spawn during
563 startup and reconfigure to service external acl lookups
564 of this type. (default 0)
566 Number of acl helper processes to keep ahead of traffic
567 loads. Squid will spawn this many at once whenever load
568 rises above the capabilities of existing processes.
569 Up to the value of children-max. (default 1)
570 concurrency=n concurrency level per process. Only used with helpers
571 capable of processing more than one query at a time.
572 cache=n limit the result cache size, default is unbounded.
573 grace=n Percentage remaining of TTL where a refresh of a
574 cached entry should be initiated without needing to
575 wait for a new reply. (default is for no grace period)
576 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
577 ipv4 / ipv6 IP protocol used to communicate with this helper.
578 The default is to auto-detect IPv6 and use it when available.
580 FORMAT specifications
582 %LOGIN Authenticated user login name
583 %EXT_USER Username from previous external acl
584 %EXT_LOG Log details from previous external acl
585 %EXT_TAG Tag from previous external acl
586 %IDENT Ident user name
588 %SRCPORT Client source port
591 %PROTO Requested protocol
593 %PATH Requested URL path
594 %METHOD Request method
595 %MYADDR Squid interface address
596 %MYPORT Squid http_port number
597 %PATH Requested URL-path (including query-string if any)
598 %USER_CERT SSL User certificate in PEM format
599 %USER_CERTCHAIN SSL User certificate chain in PEM format
600 %USER_CERT_xx SSL User certificate subject attribute xx
601 %USER_CA_xx SSL User certificate issuer attribute xx
603 %>{Header} HTTP request header "Header"
605 HTTP request header "Hdr" list member "member"
607 HTTP request header list member using ; as
608 list separator. ; can be any non-alphanumeric
611 %<{Header} HTTP reply header "Header"
613 HTTP reply header "Hdr" list member "member"
615 HTTP reply header list member using ; as
616 list separator. ; can be any non-alphanumeric
619 %% The percent sign. Useful for helpers which need
620 an unchanging input format.
622 In addition to the above, any string specified in the referencing
623 acl will also be included in the helper request line, after the
624 specified formats (see the "acl external" directive)
626 The helper receives lines per the above format specification,
627 and returns lines starting with OK or ERR indicating the validity
628 of the request and optionally followed by additional keywords with
631 General result syntax:
633 OK/ERR keyword=value ...
637 user= The users name (login)
638 password= The users password (for login= cache_peer option)
639 message= Message describing the reason. Available as %o
641 tag= Apply a tag to a request (for both ERR and OK results)
642 Only sets a tag, does not alter existing tags.
643 log= String to be logged in access.log. Available as
644 %ea in logformat specifications
646 If protocol=3.0 (the default) then URL escaping is used to protect
647 each value in both requests and responses.
649 If using protocol=2.5 then all values need to be enclosed in quotes
650 if they may contain whitespace, or the whitespace escaped using \.
651 And quotes or \ characters within the keyword value must be \ escaped.
653 When using the concurrency= option the protocol is changed by
654 introducing a query channel tag infront of the request/response.
655 The query channel tag is a number between 0 and concurrency-1.
662 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
663 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
664 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
665 DEFAULT: ssl::certUntrusted ssl_error X509_V_ERR_INVALID_CA X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY X509_V_ERR_CERT_UNTRUSTED
666 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
669 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
670 DEFAULT: localhost src 127.0.0.1/32 ::1
671 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
672 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
674 Defining an Access List
676 Every access list definition must begin with an aclname and acltype,
677 followed by either type-specific arguments or a quoted filename that
680 acl aclname acltype argument ...
681 acl aclname acltype "file" ...
683 When using "file", the file should contain one item per line.
685 By default, regular expressions are CASE-SENSITIVE.
686 To make them case-insensitive, use the -i option. To return case-sensitive
687 use the +i option between patterns, or make a new ACL line without -i.
689 Some acl types require suspending the current request in order
690 to access some external data source.
691 Those which do are marked with the tag [slow], those which
692 don't are marked as [fast].
693 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
694 for further information
696 ***** ACL TYPES AVAILABLE *****
698 acl aclname src ip-address/mask ... # clients IP address [fast]
699 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
700 acl aclname dst ip-address/mask ... # URL host's IP address [slow]
701 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
703 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
704 # The arp ACL requires the special configure option --enable-arp-acl.
705 # Furthermore, the ARP ACL code is not portable to all operating systems.
706 # It works on Linux, Solaris, Windows, FreeBSD, and some
707 # other *BSD variants.
710 # NOTE: Squid can only determine the MAC address for clients that are on
711 # the same subnet. If the client is on a different subnet,
712 # then Squid cannot find out its MAC address.
714 acl aclname srcdomain .foo.com ...
715 # reverse lookup, from client IP [slow]
716 acl aclname dstdomain .foo.com ...
717 # Destination server from URL [fast]
718 acl aclname srcdom_regex [-i] \.foo\.com ...
719 # regex matching client name [slow]
720 acl aclname dstdom_regex [-i] \.foo\.com ...
721 # regex matching server [fast]
723 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
724 # based URL is used and no match is found. The name "none" is used
725 # if the reverse lookup fails.
727 acl aclname src_as number ...
728 acl aclname dst_as number ...
730 # Except for access control, AS numbers can be used for
731 # routing of requests to specific caches. Here's an
732 # example for routing all requests for AS#1241 and only
733 # those to mycache.mydomain.net:
734 # acl asexample dst_as 1241
735 # cache_peer_access mycache.mydomain.net allow asexample
736 # cache_peer_access mycache_mydomain.net deny all
738 acl aclname peername myPeer ...
740 # match against a named cache_peer entry
741 # set unique name= on cache_peer lines for reliable use.
743 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
753 # h1:m1 must be less than h2:m2
755 acl aclname url_regex [-i] ^http:// ...
756 # regex matching on whole URL [fast]
757 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
758 # regex matching on URL login field
759 acl aclname urlpath_regex [-i] \.gif$ ...
760 # regex matching on URL path [fast]
762 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
764 acl aclname localport 3128 ... # TCP port the client connected to [fast]
765 # NP: for interception mode this is usually '80'
767 acl aclname myportname 3128 ... # http(s)_port name [fast]
769 acl aclname proto HTTP FTP ... # request protocol [fast]
771 acl aclname method GET POST ... # HTTP request method [fast]
773 acl aclname http_status 200 301 500- 400-403 ...
774 # status code in reply [fast]
776 acl aclname browser [-i] regexp ...
777 # pattern match on User-Agent header (see also req_header below) [fast]
779 acl aclname referer_regex [-i] regexp ...
780 # pattern match on Referer header [fast]
781 # Referer is highly unreliable, so use with care
783 acl aclname ident username ...
784 acl aclname ident_regex [-i] pattern ...
785 # string match on ident output [slow]
786 # use REQUIRED to accept any non-null ident.
788 acl aclname proxy_auth [-i] username ...
789 acl aclname proxy_auth_regex [-i] pattern ...
790 # perform http authentication challenge to the client and match against
791 # supplied credentials [slow]
793 # takes a list of allowed usernames.
794 # use REQUIRED to accept any valid username.
796 # Will use proxy authentication in forward-proxy scenarios, and plain
797 # http authenticaiton in reverse-proxy scenarios
799 # NOTE: when a Proxy-Authentication header is sent but it is not
800 # needed during ACL checking the username is NOT logged
803 # NOTE: proxy_auth requires a EXTERNAL authentication program
804 # to check username/password combinations (see
805 # auth_param directive).
807 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
808 # as the browser needs to be configured for using a proxy in order
809 # to respond to proxy authentication.
811 acl aclname snmp_community string ...
812 # A community string to limit access to your SNMP Agent [fast]
815 # acl snmppublic snmp_community public
817 acl aclname maxconn number
818 # This will be matched when the client's IP address has
819 # more than <number> TCP connections established. [fast]
820 # NOTE: This only measures direct TCP links so X-Forwarded-For
821 # indirect clients are not counted.
823 acl aclname max_user_ip [-s] number
824 # This will be matched when the user attempts to log in from more
825 # than <number> different ip addresses. The authenticate_ip_ttl
826 # parameter controls the timeout on the ip entries. [fast]
827 # If -s is specified the limit is strict, denying browsing
828 # from any further IP addresses until the ttl has expired. Without
829 # -s Squid will just annoy the user by "randomly" denying requests.
830 # (the counter is reset each time the limit is reached and a
832 # NOTE: in acceleration mode or where there is mesh of child proxies,
833 # clients may appear to come from multiple addresses if they are
834 # going through proxy farms, so a limit of 1 may cause user problems.
836 acl aclname random probability
837 # Pseudo-randomly match requests. Based on the probability given.
838 # Probability may be written as a decimal (0.333), fraction (1/3)
839 # or ratio of matches:non-matches (3:5).
841 acl aclname req_mime_type [-i] mime-type ...
842 # regex match against the mime type of the request generated
843 # by the client. Can be used to detect file upload or some
844 # types HTTP tunneling requests [fast]
845 # NOTE: This does NOT match the reply. You cannot use this
846 # to match the returned file type.
848 acl aclname req_header header-name [-i] any\.regex\.here
849 # regex match against any of the known request headers. May be
850 # thought of as a superset of "browser", "referer" and "mime-type"
853 acl aclname rep_mime_type [-i] mime-type ...
854 # regex match against the mime type of the reply received by
855 # squid. Can be used to detect file download or some
856 # types HTTP tunneling requests. [fast]
857 # NOTE: This has no effect in http_access rules. It only has
858 # effect in rules that affect the reply data stream such as
861 acl aclname rep_header header-name [-i] any\.regex\.here
862 # regex match against any of the known reply headers. May be
863 # thought of as a superset of "browser", "referer" and "mime-type"
866 acl aclname external class_name [arguments...]
867 # external ACL lookup via a helper class defined by the
868 # external_acl_type directive [slow]
870 acl aclname user_cert attribute values...
871 # match against attributes in a user SSL certificate
872 # attribute is one of DN/C/O/CN/L/ST [fast]
874 acl aclname ca_cert attribute values...
875 # match against attributes a users issuing CA SSL certificate
876 # attribute is one of DN/C/O/CN/L/ST [fast]
878 acl aclname ext_user username ...
879 acl aclname ext_user_regex [-i] pattern ...
880 # string match on username returned by external acl helper [slow]
881 # use REQUIRED to accept any non-null user name.
883 acl aclname tag tagvalue ...
884 # string match on tag returned by external acl helper [slow]
886 acl aclname hier_code codename ...
887 # string match against squid hierarchy code(s); [fast]
888 # e.g., DIRECT, PARENT_HIT, NONE, etc.
890 # NOTE: This has no effect in http_access rules. It only has
891 # effect in rules that affect the reply data stream such as
895 acl aclname ssl_error errorname
896 # match against SSL certificate validation error [fast]
898 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
901 # The following can be used as shortcuts for certificate properties:
902 # [ssl::]certHasExpired: the "not after" field is in the past
903 # [ssl::]certNotYetValid: the "not before" field is in the future
904 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
905 # [ssl::]certSelfSigned: The certificate is self signed.
906 # [ssl::]certDomainMismatch: The certificate CN domain does not
907 # match the name the name of the host we are connecting to.
909 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
910 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
911 # predefined ACLs, just like the 'all' ACL.
913 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
914 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
916 acl aclname server_ssl_cert_fingerprint [-sha1] fingerprint
917 # match against server SSL certificate fingerprint [fast]
919 # The fingerprint is the digest of the DER encoded version
920 # of the whole certificate. The user should use the form: XX:XX:...
921 # Optional argument specifies the digest algorithm to use.
922 # The SHA1 digest algorithm is the default and is currently
923 # the only algorithm supported (-sha1).
927 acl macaddress arp 09:00:2b:23:45:67
928 acl myexample dst_as 1241
929 acl password proxy_auth REQUIRED
930 acl fileupload req_mime_type -i ^multipart/form-data$
931 acl javascript rep_mime_type -i ^application/x-javascript$
935 # Recommended minimum configuration:
938 # Example rule allowing access from your local networks.
939 # Adapt to list your (internal) IP networks from where browsing
941 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
942 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
943 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
944 acl localnet src fc00::/7 # RFC 4193 local private network range
945 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
947 acl SSL_ports port 443
948 acl Safe_ports port 80 # http
949 acl Safe_ports port 21 # ftp
950 acl Safe_ports port 443 # https
951 acl Safe_ports port 70 # gopher
952 acl Safe_ports port 210 # wais
953 acl Safe_ports port 1025-65535 # unregistered ports
954 acl Safe_ports port 280 # http-mgmt
955 acl Safe_ports port 488 # gss-http
956 acl Safe_ports port 591 # filemaker
957 acl Safe_ports port 777 # multiling http
958 acl CONNECT method CONNECT
962 NAME: follow_x_forwarded_for
964 IFDEF: FOLLOW_X_FORWARDED_FOR
965 LOC: Config.accessList.followXFF
966 DEFAULT_IF_NONE: deny all
968 Allowing or Denying the X-Forwarded-For header to be followed to
969 find the original source of a request.
971 Requests may pass through a chain of several other proxies
972 before reaching us. The X-Forwarded-For header will contain a
973 comma-separated list of the IP addresses in the chain, with the
974 rightmost address being the most recent.
976 If a request reaches us from a source that is allowed by this
977 configuration item, then we consult the X-Forwarded-For header
978 to see where that host received the request from. If the
979 X-Forwarded-For header contains multiple addresses, we continue
980 backtracking until we reach an address for which we are not allowed
981 to follow the X-Forwarded-For header, or until we reach the first
982 address in the list. For the purpose of ACL used in the
983 follow_x_forwarded_for directive the src ACL type always matches
984 the address we are testing and srcdomain matches its rDNS.
986 The end result of this process is an IP address that we will
987 refer to as the indirect client address. This address may
988 be treated as the client address for access control, ICAP, delay
989 pools and logging, depending on the acl_uses_indirect_client,
990 icap_uses_indirect_client, delay_pool_uses_indirect_client,
991 log_uses_indirect_client and tproxy_uses_indirect_client options.
993 This clause only supports fast acl types.
994 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
996 SECURITY CONSIDERATIONS:
998 Any host for which we follow the X-Forwarded-For header
999 can place incorrect information in the header, and Squid
1000 will use the incorrect information as if it were the
1001 source address of the request. This may enable remote
1002 hosts to bypass any access control restrictions that are
1003 based on the client's source addresses.
1007 acl localhost src 127.0.0.1
1008 acl my_other_proxy srcdomain .proxy.example.com
1009 follow_x_forwarded_for allow localhost
1010 follow_x_forwarded_for allow my_other_proxy
1013 NAME: acl_uses_indirect_client
1016 IFDEF: FOLLOW_X_FORWARDED_FOR
1018 LOC: Config.onoff.acl_uses_indirect_client
1020 Controls whether the indirect client address
1021 (see follow_x_forwarded_for) is used instead of the
1022 direct client address in acl matching.
1024 NOTE: maxconn ACL considers direct TCP links and indirect
1025 clients will always have zero. So no match.
1028 NAME: delay_pool_uses_indirect_client
1031 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1033 LOC: Config.onoff.delay_pool_uses_indirect_client
1035 Controls whether the indirect client address
1036 (see follow_x_forwarded_for) is used instead of the
1037 direct client address in delay pools.
1040 NAME: log_uses_indirect_client
1043 IFDEF: FOLLOW_X_FORWARDED_FOR
1045 LOC: Config.onoff.log_uses_indirect_client
1047 Controls whether the indirect client address
1048 (see follow_x_forwarded_for) is used instead of the
1049 direct client address in the access log.
1052 NAME: tproxy_uses_indirect_client
1055 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1057 LOC: Config.onoff.tproxy_uses_indirect_client
1059 Controls whether the indirect client address
1060 (see follow_x_forwarded_for) is used instead of the
1061 direct client address when spoofing the outgoing client.
1063 This has no effect on requests arriving in non-tproxy
1066 SECURITY WARNING: Usage of this option is dangerous
1067 and should not be used trivially. Correct configuration
1068 of follow_x_forewarded_for with a limited set of trusted
1069 sources is required to prevent abuse of your proxy.
1074 LOC: Config.accessList.http
1075 DEFAULT_IF_NONE: deny all
1077 Allowing or Denying access based on defined access lists
1079 Access to the HTTP port:
1080 http_access allow|deny [!]aclname ...
1082 NOTE on default values:
1084 If there are no "access" lines present, the default is to deny
1087 If none of the "access" lines cause a match, the default is the
1088 opposite of the last line in the list. If the last line was
1089 deny, the default is allow. Conversely, if the last line
1090 is allow, the default will be deny. For these reasons, it is a
1091 good idea to have an "deny all" entry at the end of your access
1092 lists to avoid potential confusion.
1094 This clause supports both fast and slow acl types.
1095 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1100 # Recommended minimum Access Permission configuration:
1102 # Only allow cachemgr access from localhost
1103 http_access allow localhost manager
1104 http_access deny manager
1106 # Deny requests to certain unsafe ports
1107 http_access deny !Safe_ports
1109 # Deny CONNECT to other than secure SSL ports
1110 http_access deny CONNECT !SSL_ports
1112 # We strongly recommend the following be uncommented to protect innocent
1113 # web applications running on the proxy server who think the only
1114 # one who can access services on "localhost" is a local user
1115 #http_access deny to_localhost
1118 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1121 # Example rule allowing access from your local networks.
1122 # Adapt localnet in the ACL section to list your (internal) IP networks
1123 # from where browsing should be allowed
1124 http_access allow localnet
1125 http_access allow localhost
1127 # And finally deny all other access to this proxy
1128 http_access deny all
1132 NAME: adapted_http_access http_access2
1134 LOC: Config.accessList.adapted_http
1137 Allowing or Denying access based on defined access lists
1139 Essentially identical to http_access, but runs after redirectors
1140 and ICAP/eCAP adaptation. Allowing access control based on their
1143 If not set then only http_access is used.
1146 NAME: http_reply_access
1148 LOC: Config.accessList.reply
1151 Allow replies to client requests. This is complementary to http_access.
1153 http_reply_access allow|deny [!] aclname ...
1155 NOTE: if there are no access lines present, the default is to allow
1158 If none of the access lines cause a match the opposite of the
1159 last line will apply. Thus it is good practice to end the rules
1160 with an "allow all" or "deny all" entry.
1162 This clause supports both fast and slow acl types.
1163 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1168 LOC: Config.accessList.icp
1169 DEFAULT_IF_NONE: deny all
1171 Allowing or Denying access to the ICP port based on defined
1174 icp_access allow|deny [!]aclname ...
1176 See http_access for details
1178 This clause only supports fast acl types.
1179 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1181 # Allow ICP queries from local networks only
1182 #icp_access allow localnet
1183 #icp_access deny all
1189 LOC: Config.accessList.htcp
1190 DEFAULT_IF_NONE: deny all
1192 Allowing or Denying access to the HTCP port based on defined
1195 htcp_access allow|deny [!]aclname ...
1197 See http_access for details
1199 NOTE: The default if no htcp_access lines are present is to
1200 deny all traffic. This default may cause problems with peers
1201 using the htcp option.
1203 This clause only supports fast acl types.
1204 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1206 # Allow HTCP queries from local networks only
1207 #htcp_access allow localnet
1208 #htcp_access deny all
1211 NAME: htcp_clr_access
1214 LOC: Config.accessList.htcp_clr
1215 DEFAULT_IF_NONE: deny all
1217 Allowing or Denying access to purge content using HTCP based
1218 on defined access lists
1220 htcp_clr_access allow|deny [!]aclname ...
1222 See http_access for details
1224 This clause only supports fast acl types.
1225 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1227 # Allow HTCP CLR requests from trusted peers
1228 acl htcp_clr_peer src 172.16.1.2
1229 htcp_clr_access allow htcp_clr_peer
1234 LOC: Config.accessList.miss
1237 Determins whether network access is permitted when satisfying a request.
1240 to force your neighbors to use you as a sibling instead of
1243 acl localclients src 172.16.0.0/16
1244 miss_access allow localclients
1245 miss_access deny !localclients
1247 This means only your local clients are allowed to fetch relayed/MISS
1248 replies from the network and all other clients can only fetch cached
1252 The default for this setting allows all clients who passed the
1253 http_access rules to relay via this proxy.
1255 This clause only supports fast acl types.
1256 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1259 NAME: ident_lookup_access
1262 DEFAULT_IF_NONE: deny all
1263 LOC: Ident::TheConfig.identLookup
1265 A list of ACL elements which, if matched, cause an ident
1266 (RFC 931) lookup to be performed for this request. For
1267 example, you might choose to always perform ident lookups
1268 for your main multi-user Unix boxes, but not for your Macs
1269 and PCs. By default, ident lookups are not performed for
1272 To enable ident lookups for specific client addresses, you
1273 can follow this example:
1275 acl ident_aware_hosts src 198.168.1.0/24
1276 ident_lookup_access allow ident_aware_hosts
1277 ident_lookup_access deny all
1279 Only src type ACL checks are fully supported. A srcdomain
1280 ACL might work at times, but it will not always provide
1283 This clause only supports fast acl types.
1284 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1287 NAME: reply_body_max_size
1288 COMMENT: size [acl acl...]
1291 LOC: Config.ReplyBodySize
1293 This option specifies the maximum size of a reply body. It can be
1294 used to prevent users from downloading very large files, such as
1295 MP3's and movies. When the reply headers are received, the
1296 reply_body_max_size lines are processed, and the first line where
1297 all (if any) listed ACLs are true is used as the maximum body size
1300 This size is checked twice. First when we get the reply headers,
1301 we check the content-length value. If the content length value exists
1302 and is larger than the allowed size, the request is denied and the
1303 user receives an error message that says "the request or reply
1304 is too large." If there is no content-length, and the reply
1305 size exceeds this limit, the client's connection is just closed
1306 and they will receive a partial reply.
1308 WARNING: downstream caches probably can not detect a partial reply
1309 if there is no content-length header, so they will cache
1310 partial responses and give them out as hits. You should NOT
1311 use this option if you have downstream caches.
1313 WARNING: A maximum size smaller than the size of squid's error messages
1314 will cause an infinite loop and crash squid. Ensure that the smallest
1315 non-zero value you use is greater that the maximum header size plus
1316 the size of your largest error page.
1318 If you set this parameter none (the default), there will be
1321 Configuration Format is:
1322 reply_body_max_size SIZE UNITS [acl ...]
1324 reply_body_max_size 10 MB
1330 -----------------------------------------------------------------------------
1333 NAME: http_port ascii_port
1336 LOC: Config.Sockaddr.http
1338 Usage: port [mode] [options]
1339 hostname:port [mode] [options]
1340 1.2.3.4:port [mode] [options]
1342 The socket addresses where Squid will listen for HTTP client
1343 requests. You may specify multiple socket addresses.
1344 There are three forms: port alone, hostname with port, and
1345 IP address with port. If you specify a hostname or IP
1346 address, Squid binds the socket to that specific
1347 address. Most likely, you do not need to bind to a specific
1348 address, so you can use the port number alone.
1350 If you are running Squid in accelerator mode, you
1351 probably want to listen on port 80 also, or instead.
1353 The -a command line option may be used to specify additional
1354 port(s) where Squid listens for proxy request. Such ports will
1355 be plain proxy ports with no options.
1357 You may specify multiple socket addresses on multiple lines.
1361 intercept Support for IP-Layer interception of
1362 outgoing requests without browser settings.
1363 NP: disables authentication and IPv6 on the port.
1365 tproxy Support Linux TPROXY for spoofing outgoing
1366 connections using the client IP address.
1367 NP: disables authentication and maybe IPv6 on the port.
1369 accel Accelerator / reverse proxy mode
1371 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1372 establish secure connection with the client and with
1373 the server, decrypt HTTPS messages as they pass through
1374 Squid, and treat them as unencrypted HTTP messages,
1375 becoming the man-in-the-middle.
1377 The ssl_bump option is required to fully enable
1378 bumping of CONNECT requests.
1380 Omitting the mode flag causes default forward proxy mode to be used.
1383 Accelerator Mode Options:
1385 defaultsite=domainname
1386 What to use for the Host: header if it is not present
1387 in a request. Determines what site (not origin server)
1388 accelerators should consider the default.
1390 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1392 protocol= Protocol to reconstruct accelerated requests with.
1393 Defaults to http for http_port and https for
1396 vport Virtual host port support. Using the http_port number
1397 instead of the port passed on Host: headers.
1399 vport=NN Virtual host port support. Using the specified port
1400 number instead of the port passed on Host: headers.
1403 Act as if this Squid is the origin server.
1404 This currently means generate new Date: and Expires:
1405 headers on HIT instead of adding Age:.
1407 ignore-cc Ignore request Cache-Control headers.
1409 WARNING: This option violates HTTP specifications if
1410 used in non-accelerator setups.
1412 allow-direct Allow direct forwarding in accelerator mode. Normally
1413 accelerated requests are denied direct forwarding as if
1414 never_direct was used.
1416 WARNING: this option opens accelerator mode to security
1417 vulnerabilities usually only affecting in interception
1418 mode. Make sure to protect forwarding with suitable
1419 http_access rules when using this.
1422 SSL Bump Mode Options:
1423 In addition to these options ssl-bump requires TLS/SSL options.
1425 generate-host-certificates[=<on|off>]
1426 Dynamically create SSL server certificates for the
1427 destination hosts of bumped CONNECT requests.When
1428 enabled, the cert and key options are used to sign
1429 generated certificates. Otherwise generated
1430 certificate will be selfsigned.
1431 If there is a CA certificate lifetime of the generated
1432 certificate equals lifetime of the CA certificate. If
1433 generated certificate is selfsigned lifetime is three
1435 This option is enabled by default when ssl-bump is used.
1436 See the ssl-bump option above for more information.
1438 dynamic_cert_mem_cache_size=SIZE
1439 Approximate total RAM size spent on cached generated
1440 certificates. If set to zero, caching is disabled. The
1441 default value is 4MB.
1445 cert= Path to SSL certificate (PEM format).
1447 key= Path to SSL private key file (PEM format)
1448 if not specified, the certificate file is
1449 assumed to be a combined certificate and
1452 version= The version of SSL/TLS supported
1453 1 automatic (default)
1460 cipher= Colon separated list of supported ciphers.
1461 NOTE: some ciphers such as EDH ciphers depend on
1462 additional settings. If those settings are
1463 omitted the ciphers may be silently ignored
1464 by the OpenSSL library.
1466 options= Various SSL implementation options. The most important
1468 NO_SSLv2 Disallow the use of SSLv2
1469 NO_SSLv3 Disallow the use of SSLv3
1470 NO_TLSv1 Disallow the use of TLSv1.0
1471 NO_TLSv1_1 Disallow the use of TLSv1.1
1472 NO_TLSv1_2 Disallow the use of TLSv1.2
1473 SINGLE_DH_USE Always create a new key when using
1474 temporary/ephemeral DH key exchanges
1475 ALL Enable various bug workarounds
1476 suggested as "harmless" by OpenSSL
1477 Be warned that this reduces SSL/TLS
1478 strength to some attacks.
1479 See OpenSSL SSL_CTX_set_options documentation for a
1480 complete list of options.
1482 clientca= File containing the list of CAs to use when
1483 requesting a client certificate.
1485 cafile= File containing additional CA certificates to
1486 use when verifying client certificates. If unset
1487 clientca will be used.
1489 capath= Directory containing additional CA certificates
1490 and CRL lists to use when verifying client certificates.
1492 crlfile= File of additional CRL lists to use when verifying
1493 the client certificate, in addition to CRLs stored in
1494 the capath. Implies VERIFY_CRL flag below.
1496 dhparams= File containing DH parameters for temporary/ephemeral
1497 DH key exchanges. See OpenSSL documentation for details
1498 on how to create this file.
1499 WARNING: EDH ciphers will be silently disabled if this
1502 sslflags= Various flags modifying the use of SSL:
1504 Don't request client certificates
1505 immediately, but wait until acl processing
1506 requires a certificate (not yet implemented).
1508 Don't use the default CA lists built in
1511 Don't allow for session reuse. Each connection
1512 will result in a new SSL session.
1514 Verify CRL lists when accepting client
1517 Verify CRL lists for all certificates in the
1518 client certificate chain.
1520 sslcontext= SSL session ID context identifier.
1524 connection-auth[=on|off]
1525 use connection-auth=off to tell Squid to prevent
1526 forwarding Microsoft connection oriented authentication
1527 (NTLM, Negotiate and Kerberos)
1529 disable-pmtu-discovery=
1530 Control Path-MTU discovery usage:
1531 off lets OS decide on what to do (default).
1532 transparent disable PMTU discovery when transparent
1534 always disable always PMTU discovery.
1536 In many setups of transparently intercepting proxies
1537 Path-MTU discovery can not work on traffic towards the
1538 clients. This is the case when the intercepting device
1539 does not fully track connections and fails to forward
1540 ICMP must fragment messages to the cache server. If you
1541 have such setup and experience that certain clients
1542 sporadically hang or never complete requests set
1543 disable-pmtu-discovery option to 'transparent'.
1545 name= Specifies a internal name for the port. Defaults to
1546 the port specification (port or addr:port)
1548 tcpkeepalive[=idle,interval,timeout]
1549 Enable TCP keepalive probes of idle connections.
1550 In seconds; idle is the initial time before TCP starts
1551 probing the connection, interval how often to probe, and
1552 timeout the time before giving up.
1554 If you run Squid on a dual-homed machine with an internal
1555 and an external interface we recommend you to specify the
1556 internal address:port in http_port. This way Squid will only be
1557 visible on the internal address.
1561 # Squid normally listens to port 3128
1562 http_port @DEFAULT_HTTP_PORT@
1570 LOC: Config.Sockaddr.https
1572 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1574 The socket address where Squid will listen for client requests made
1575 over TLS or SSL connections. Commonly referred to as HTTPS.
1577 This is most useful for situations where you are running squid in
1578 accelerator mode and you want to do the SSL work at the accelerator level.
1580 You may specify multiple socket addresses on multiple lines,
1581 each with their own SSL certificate and/or options.
1585 accel Accelerator / reverse proxy mode
1587 intercept Support for IP-Layer interception of
1588 outgoing requests without browser settings.
1589 NP: disables authentication and IPv6 on the port.
1591 tproxy Support Linux TPROXY for spoofing outgoing
1592 connections using the client IP address.
1593 NP: disables authentication and maybe IPv6 on the port.
1595 ssl-bump For each intercepted connection allowed by ssl_bump
1596 ACLs, establish a secure connection with the client and with
1597 the server, decrypt HTTPS messages as they pass through
1598 Squid, and treat them as unencrypted HTTP messages,
1599 becoming the man-in-the-middle.
1601 An "ssl_bump server-first" match is required to
1602 fully enable bumping of intercepted SSL connections.
1604 Requires tproxy or intercept.
1606 Omitting the mode flag causes default forward proxy mode to be used.
1609 See http_port for a list of generic options
1614 cert= Path to SSL certificate (PEM format).
1616 key= Path to SSL private key file (PEM format)
1617 if not specified, the certificate file is
1618 assumed to be a combined certificate and
1621 version= The version of SSL/TLS supported
1622 1 automatic (default)
1627 cipher= Colon separated list of supported ciphers.
1629 options= Various SSL engine options. The most important
1631 NO_SSLv2 Disallow the use of SSLv2
1632 NO_SSLv3 Disallow the use of SSLv3
1633 NO_TLSv1 Disallow the use of TLSv1
1634 SINGLE_DH_USE Always create a new key when using
1635 temporary/ephemeral DH key exchanges
1636 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1637 documentation for a complete list of options.
1639 clientca= File containing the list of CAs to use when
1640 requesting a client certificate.
1642 cafile= File containing additional CA certificates to
1643 use when verifying client certificates. If unset
1644 clientca will be used.
1646 capath= Directory containing additional CA certificates
1647 and CRL lists to use when verifying client certificates.
1649 crlfile= File of additional CRL lists to use when verifying
1650 the client certificate, in addition to CRLs stored in
1651 the capath. Implies VERIFY_CRL flag below.
1653 dhparams= File containing DH parameters for temporary/ephemeral
1656 sslflags= Various flags modifying the use of SSL:
1658 Don't request client certificates
1659 immediately, but wait until acl processing
1660 requires a certificate (not yet implemented).
1662 Don't use the default CA lists built in
1665 Don't allow for session reuse. Each connection
1666 will result in a new SSL session.
1668 Verify CRL lists when accepting client
1671 Verify CRL lists for all certificates in the
1672 client certificate chain.
1674 sslcontext= SSL session ID context identifier.
1676 generate-host-certificates[=<on|off>]
1677 Dynamically create SSL server certificates for the
1678 destination hosts of bumped SSL requests.When
1679 enabled, the cert and key options are used to sign
1680 generated certificates. Otherwise generated
1681 certificate will be selfsigned.
1682 If there is CA certificate life time of generated
1683 certificate equals lifetime of CA certificate. If
1684 generated certificate is selfsigned lifetime is three
1686 This option is enabled by default when SslBump is used.
1687 See the sslBump option above for more information.
1689 dynamic_cert_mem_cache_size=SIZE
1690 Approximate total RAM size spent on cached generated
1691 certificates. If set to zero, caching is disabled. The
1692 default value is 4MB.
1694 See http_port for a list of available options.
1697 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1700 LOC: Ip::Qos::TheConfig.tosToServer
1702 Allows you to select a TOS/Diffserv value for packets outgoing
1703 on the server side, based on an ACL.
1705 tcp_outgoing_tos ds-field [!]aclname ...
1707 Example where normal_service_net uses the TOS value 0x00
1708 and good_service_net uses 0x20
1710 acl normal_service_net src 10.0.0.0/24
1711 acl good_service_net src 10.0.1.0/24
1712 tcp_outgoing_tos 0x00 normal_service_net
1713 tcp_outgoing_tos 0x20 good_service_net
1715 TOS/DSCP values really only have local significance - so you should
1716 know what you're specifying. For more information, see RFC2474,
1717 RFC2475, and RFC3260.
1719 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1720 "default" to use whatever default your host has. Note that in
1721 practice often only multiples of 4 is usable as the two rightmost bits
1722 have been redefined for use by ECN (RFC 3168 section 23.1).
1724 Processing proceeds in the order specified, and stops at first fully
1728 NAME: clientside_tos
1731 LOC: Ip::Qos::TheConfig.tosToClient
1733 Allows you to select a TOS/Diffserv value for packets being transmitted
1734 on the client-side, based on an ACL.
1736 clientside_tos ds-field [!]aclname ...
1738 Example where normal_service_net uses the TOS value 0x00
1739 and good_service_net uses 0x20
1741 acl normal_service_net src 10.0.0.0/24
1742 acl good_service_net src 10.0.1.0/24
1743 clientside_tos 0x00 normal_service_net
1744 clientside_tos 0x20 good_service_net
1746 Note: This feature is incompatible with qos_flows. Any TOS values set here
1747 will be overwritten by TOS values in qos_flows.
1750 NAME: tcp_outgoing_mark
1752 IFDEF: SO_MARK&&USE_LIBCAP
1754 LOC: Ip::Qos::TheConfig.nfmarkToServer
1756 Allows you to apply a Netfilter mark value to outgoing packets
1757 on the server side, based on an ACL.
1759 tcp_outgoing_mark mark-value [!]aclname ...
1761 Example where normal_service_net uses the mark value 0x00
1762 and good_service_net uses 0x20
1764 acl normal_service_net src 10.0.0.0/24
1765 acl good_service_net src 10.0.1.0/24
1766 tcp_outgoing_mark 0x00 normal_service_net
1767 tcp_outgoing_mark 0x20 good_service_net
1770 NAME: clientside_mark
1772 IFDEF: SO_MARK&&USE_LIBCAP
1774 LOC: Ip::Qos::TheConfig.nfmarkToClient
1776 Allows you to apply a Netfilter mark value to packets being transmitted
1777 on the client-side, based on an ACL.
1779 clientside_mark mark-value [!]aclname ...
1781 Example where normal_service_net uses the mark value 0x00
1782 and good_service_net uses 0x20
1784 acl normal_service_net src 10.0.0.0/24
1785 acl good_service_net src 10.0.1.0/24
1786 clientside_mark 0x00 normal_service_net
1787 clientside_mark 0x20 good_service_net
1789 Note: This feature is incompatible with qos_flows. Any mark values set here
1790 will be overwritten by mark values in qos_flows.
1797 LOC: Ip::Qos::TheConfig
1799 Allows you to select a TOS/DSCP value to mark outgoing
1800 connections with, based on where the reply was sourced. For
1801 platforms using netfilter, allows you to set a netfilter mark
1802 value instead of, or in addition to, a TOS value.
1804 TOS values really only have local significance - so you should
1805 know what you're specifying. For more information, see RFC2474,
1806 RFC2475, and RFC3260.
1808 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1809 in practice often only multiples of 4 is usable as the two rightmost bits
1810 have been redefined for use by ECN (RFC 3168 section 23.1).
1812 Mark values can be any unsigned 32-bit integer value.
1814 This setting is configured by setting the following values:
1816 tos|mark Whether to set TOS or netfilter mark values
1818 local-hit=0xFF Value to mark local cache hits.
1820 sibling-hit=0xFF Value to mark hits from sibling peers.
1822 parent-hit=0xFF Value to mark hits from parent peers.
1824 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
1825 over the preserve-miss feature (see below), unless
1826 mask is specified, in which case only the bits
1827 specified in the mask are written.
1829 The TOS variant of the following features are only possible on Linux
1830 and require your kernel to be patched with the TOS preserving ZPH
1831 patch, available from http://zph.bratcheda.org
1832 No patch is needed to preserve the netfilter mark, which will work
1833 with all variants of netfilter.
1835 disable-preserve-miss
1836 This option disables the preservation of the TOS or netfilter
1837 mark. By default, the existing TOS or netfilter mark value of
1838 the response coming from the remote server will be retained
1839 and masked with miss-mark.
1840 NOTE: in the case of a netfilter mark, the mark must be set on
1841 the connection (using the CONNMARK target) not on the packet
1845 Allows you to mask certain bits in the TOS or mark value
1846 received from the remote server, before copying the value to
1847 the TOS sent towards clients.
1848 Default for tos: 0xFF (TOS from server is not changed).
1849 Default for mark: 0xFFFFFFFF (mark from server is not changed).
1851 All of these features require the --enable-zph-qos compilation flag
1852 (enabled by default). Netfilter marking also requires the
1853 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
1854 libcap 2.09+ (--with-libcap).
1858 NAME: tcp_outgoing_address
1861 LOC: Config.accessList.outgoing_address
1863 Allows you to map requests to different outgoing IP addresses
1864 based on the username or source address of the user making
1867 tcp_outgoing_address ipaddr [[!]aclname] ...
1870 Forwarding clients with dedicated IPs for certain subnets.
1872 acl normal_service_net src 10.0.0.0/24
1873 acl good_service_net src 10.0.2.0/24
1875 tcp_outgoing_address 2001:db8::c001 good_service_net
1876 tcp_outgoing_address 10.1.0.2 good_service_net
1878 tcp_outgoing_address 2001:db8::beef normal_service_net
1879 tcp_outgoing_address 10.1.0.1 normal_service_net
1881 tcp_outgoing_address 2001:db8::1
1882 tcp_outgoing_address 10.1.0.3
1884 Processing proceeds in the order specified, and stops at first fully
1887 Squid will add an implicit IP version test to each line.
1888 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
1889 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
1892 NOTE: The use of this directive using client dependent ACLs is
1893 incompatible with the use of server side persistent connections. To
1894 ensure correct results it is best to set server_persistent_connections
1895 to off when using this directive in such configurations.
1897 NOTE: The use of this directive to set a local IP on outgoing TCP links
1898 is incompatible with using TPROXY to set client IP out outbound TCP links.
1899 When needing to contact peers use the no-tproxy cache_peer option and the
1900 client_dst_passthru directive re-enable normal forwarding such as this.
1904 NAME: host_verify_strict
1907 LOC: Config.onoff.hostStrictVerify
1909 Regardless of this option setting, when dealing with intercepted
1910 traffic, Squid always verifies that the destination IP address matches
1911 the Host header domain or IP (called 'authority form URL').
1913 This enforcement is performed to satisfy a MUST-level requirement in
1914 RFC 2616 section 14.23: "The Host field value MUST represent the naming
1915 authority of the origin server or gateway given by the original URL".
1918 Squid always responds with an HTTP 409 (Conflict) error
1919 page and logs a security warning if there is no match.
1921 Squid verifies that the destination IP address matches
1922 the Host header for forward-proxy and reverse-proxy traffic
1923 as well. For those traffic types, Squid also enables the
1924 following checks, comparing the corresponding Host header
1925 and Request-URI components:
1927 * The host names (domain or IP) must be identical,
1928 but valueless or missing Host header disables all checks.
1929 For the two host names to match, both must be either IP
1932 * Port numbers must be identical, but if a port is missing
1933 the scheme-default port is assumed.
1936 When set to OFF (the default):
1937 Squid allows suspicious requests to continue but logs a
1938 security warning and blocks caching of the response.
1940 * Forward-proxy traffic is not checked at all.
1942 * Reverse-proxy traffic is not checked at all.
1944 * Intercepted traffic which passes verification is handled
1945 according to client_dst_passthru.
1947 * Intercepted requests which fail verification are sent
1948 to the client original destination instead of DIRECT.
1949 This overrides 'client_dst_passthru off'.
1951 For now suspicious intercepted CONNECT requests are always
1952 responded to with an HTTP 409 (Conflict) error page.
1957 As described in CVE-2009-0801 when the Host: header alone is used
1958 to determine the destination of a request it becomes trivial for
1959 malicious scripts on remote websites to bypass browser same-origin
1960 security policy and sandboxing protections.
1962 The cause of this is that such applets are allowed to perform their
1963 own HTTP stack, in which case the same-origin policy of the browser
1964 sandbox only verifies that the applet tries to contact the same IP
1965 as from where it was loaded at the IP level. The Host: header may
1966 be different from the connected IP and approved origin.
1970 NAME: client_dst_passthru
1973 LOC: Config.onoff.client_dst_passthru
1975 With NAT or TPROXY intercepted traffic Squid may pass the request
1976 directly to the original client destination IP or seek a faster
1977 source using the HTTP Host header.
1979 Using Host to locate alternative servers can provide faster
1980 connectivity with a range of failure recovery options.
1981 But can also lead to connectivity trouble when the client and
1982 server are attempting stateful interactions unaware of the proxy.
1984 This option (on by default) prevents alternative DNS entries being
1985 located to send intercepted traffic DIRECT to an origin server.
1986 The clients original destination IP and port will be used instead.
1988 Regardless of this option setting, when dealing with intercepted
1989 traffic Squid will verify the Host: header and any traffic which
1990 fails Host verification will be treated as if this option were ON.
1992 see host_verify_strict for details on the verification process.
1997 -----------------------------------------------------------------------------
2000 NAME: ssl_unclean_shutdown
2004 LOC: Config.SSL.unclean_shutdown
2006 Some browsers (especially MSIE) bugs out on SSL shutdown
2013 LOC: Config.SSL.ssl_engine
2016 The OpenSSL engine to use. You will need to set this if you
2017 would like to use hardware SSL acceleration for example.
2020 NAME: sslproxy_client_certificate
2023 LOC: Config.ssl_client.cert
2026 Client SSL Certificate to use when proxying https:// URLs
2029 NAME: sslproxy_client_key
2032 LOC: Config.ssl_client.key
2035 Client SSL Key to use when proxying https:// URLs
2038 NAME: sslproxy_version
2041 LOC: Config.ssl_client.version
2044 SSL version level to use when proxying https:// URLs
2046 The versions of SSL/TLS supported:
2048 1 automatic (default)
2056 NAME: sslproxy_options
2059 LOC: Config.ssl_client.options
2062 SSL implementation options to use when proxying https:// URLs
2064 The most important being:
2066 NO_SSLv2 Disallow the use of SSLv2
2067 NO_SSLv3 Disallow the use of SSLv3
2068 NO_TLSv1 Disallow the use of TLSv1.0
2069 NO_TLSv1_1 Disallow the use of TLSv1.1
2070 NO_TLSv1_2 Disallow the use of TLSv1.2
2072 Always create a new key when using temporary/ephemeral
2075 Disable use of RFC5077 session tickets. Some servers
2076 may have problems understanding the TLS extension due
2077 to ambiguous specification in RFC4507.
2078 ALL Enable various bug workarounds suggested as "harmless"
2079 by OpenSSL. Be warned that this may reduce SSL/TLS
2080 strength to some attacks.
2082 See the OpenSSL SSL_CTX_set_options documentation for a
2083 complete list of possible options.
2086 NAME: sslproxy_cipher
2089 LOC: Config.ssl_client.cipher
2092 SSL cipher list to use when proxying https:// URLs
2094 Colon separated list of supported ciphers.
2097 NAME: sslproxy_cafile
2100 LOC: Config.ssl_client.cafile
2103 file containing CA certificates to use when verifying server
2104 certificates while proxying https:// URLs
2107 NAME: sslproxy_capath
2110 LOC: Config.ssl_client.capath
2113 directory containing CA certificates to use when verifying
2114 server certificates while proxying https:// URLs
2119 TYPE: sslproxy_ssl_bump
2120 LOC: Config.accessList.ssl_bump
2123 This option is consulted when a CONNECT request is received on
2124 an http_port (or a new connection is intercepted at an
2125 https_port), provided that port was configured with an ssl-bump
2126 flag. The subsequent data on the connection is either treated as
2127 HTTPS and decrypted OR tunneled at TCP level without decryption,
2128 depending on the first bumping "mode" which ACLs match.
2130 ssl_bump <mode> [!]acl ...
2132 The following bumping modes are supported:
2135 Allow bumping of the connection. Establish a secure connection
2136 with the client first, then connect to the server. This old mode
2137 does not allow Squid to mimic server SSL certificate and does
2138 not work with intercepted SSL connections.
2141 Allow bumping of the connection. Establish a secure connection
2142 with the server first, then establish a secure connection with
2143 the client, using a mimicked server certificate. Works with both
2144 CONNECT requests and intercepted SSL connections.
2147 Become a TCP tunnel without decoding the connection.
2148 Works with both CONNECT requests and intercepted SSL
2149 connections. This is the default behavior when no
2150 ssl_bump option is given or no ssl_bump ACLs match.
2152 By default, no connections are bumped.
2154 The first matching ssl_bump option wins. If no ACLs match, the
2155 connection is not bumped. Unlike most allow/deny ACL lists, ssl_bump
2156 does not have an implicit "negate the last given option" rule. You
2157 must make that rule explicit if you convert old ssl_bump allow/deny
2158 rules that rely on such an implicit rule.
2160 This clause supports both fast and slow acl types.
2161 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2163 See also: http_port ssl-bump, https_port ssl-bump
2166 # Example: Bump all requests except those originating from
2167 # localhost and those going to example.com.
2169 acl broken_sites dstdomain .example.com
2170 ssl_bump none localhost
2171 ssl_bump none broken_sites
2172 ssl_bump server-first all
2175 NAME: sslproxy_flags
2178 LOC: Config.ssl_client.flags
2181 Various flags modifying the use of SSL while proxying https:// URLs:
2182 DONT_VERIFY_PEER Accept certificates that fail verification.
2183 For refined control, see sslproxy_cert_error.
2184 NO_DEFAULT_CA Don't use the default CA list built in
2188 NAME: sslproxy_cert_error
2191 LOC: Config.ssl_client.cert_error
2194 Use this ACL to bypass server certificate validation errors.
2196 For example, the following lines will bypass all validation errors
2197 when talking to servers for example.com. All other
2198 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2200 acl BrokenButTrustedServers dstdomain example.com
2201 sslproxy_cert_error allow BrokenButTrustedServers
2202 sslproxy_cert_error deny all
2204 This clause only supports fast acl types.
2205 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2206 Using slow acl types may result in server crashes
2208 Without this option, all server certificate validation errors
2209 terminate the transaction. Bypassing validation errors is dangerous
2210 because an error usually implies that the server cannot be trusted and
2211 the connection may be insecure.
2213 See also: sslproxy_flags and DONT_VERIFY_PEER.
2215 Default setting: sslproxy_cert_error deny all
2218 NAME: sslproxy_cert_sign
2221 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2222 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2223 POSTSCRIPTUM: signTrusted all
2224 TYPE: sslproxy_cert_sign
2225 LOC: Config.ssl_client.cert_sign
2228 sslproxy_cert_sign <signing algorithm> acl ...
2230 The following certificate signing algorithms are supported:
2232 Sign using the configured CA certificate which is usually
2233 placed in and trusted by end-user browsers. This is the
2234 default for trusted origin server certificates.
2236 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2237 This is the default for untrusted origin server certificates
2238 that are not self-signed (see ssl::certUntrusted).
2240 Sign using a self-signed certificate with the right CN to
2241 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2242 browser. This is the default for self-signed origin server
2243 certificates (see ssl::certSelfSigned).
2245 This clause only supports fast acl types.
2247 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2248 signing algorithm to generate the certificate and ignores all
2249 subsequent sslproxy_cert_sign options (the first match wins). If no
2250 acl(s) match, the default signing algorithm is determined by errors
2251 detected when obtaining and validating the origin server certificate.
2253 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2254 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2255 CONNECT request that carries a domain name. In all other cases (CONNECT
2256 to an IP address or an intercepted SSL connection), Squid cannot detect
2257 the domain mismatch at certificate generation time when
2258 bump-server-first is used.
2261 NAME: sslproxy_cert_adapt
2264 TYPE: sslproxy_cert_adapt
2265 LOC: Config.ssl_client.cert_adapt
2268 sslproxy_cert_adapt <adaptation algorithm> acl ...
2270 The following certificate adaptation algorithms are supported:
2272 Sets the "Not After" property to the "Not After" property of
2273 the CA certificate used to sign generated certificates.
2275 Sets the "Not Before" property to the "Not Before" property of
2276 the CA certificate used to sign generated certificates.
2277 setCommonName or setCommonName{CN}
2278 Sets Subject.CN property to the host name specified as a
2279 CN parameter or, if no explicit CN parameter was specified,
2280 extracted from the CONNECT request. It is a misconfiguration
2281 to use setCommonName without an explicit parameter for
2282 intercepted or tproxied SSL connections.
2284 This clause only supports fast acl types.
2286 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2287 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2288 corresponding adaptation algorithm to generate the certificate and
2289 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2290 group (i.e., the first match wins within each algorithm group). If no
2291 acl(s) match, the default mimicking action takes place.
2293 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2294 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2295 CONNECT request that carries a domain name. In all other cases (CONNECT
2296 to an IP address or an intercepted SSL connection), Squid cannot detect
2297 the domain mismatch at certificate generation time when
2298 bump-server-first is used.
2301 NAME: sslpassword_program
2304 LOC: Config.Program.ssl_password
2307 Specify a program used for entering SSL key passphrases
2308 when using encrypted SSL certificate keys. If not specified
2309 keys must either be unencrypted, or Squid started with the -N
2310 option to allow it to query interactively for the passphrase.
2312 The key file name is given as argument to the program allowing
2313 selection of the right password if you have multiple encrypted
2318 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2319 -----------------------------------------------------------------------------
2322 NAME: sslcrtd_program
2325 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2326 LOC: Ssl::TheConfig.ssl_crtd
2328 Specify the location and options of the executable for ssl_crtd process.
2329 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2330 For more information use:
2331 @DEFAULT_SSL_CRTD@ -h
2334 NAME: sslcrtd_children
2335 TYPE: HelperChildConfig
2337 DEFAULT: 32 startup=5 idle=1
2338 LOC: Ssl::TheConfig.ssl_crtdChildren
2340 The maximum number of processes spawn to service ssl server.
2341 The maximum this may be safely set to is 32.
2343 The startup= and idle= options allow some measure of skew in your
2348 Sets the minimum number of processes to spawn when Squid
2349 starts or reconfigures. When set to zero the first request will
2350 cause spawning of the first child process to handle it.
2352 Starting too few children temporary slows Squid under load while it
2353 tries to spawn enough additional processes to cope with traffic.
2357 Sets a minimum of how many processes Squid is to try and keep available
2358 at all times. When traffic begins to rise above what the existing
2359 processes can handle this many more will be spawned up to the maximum
2360 configured. A minimum setting of 1 is required.
2362 You must have at least one ssl_crtd process.
2365 NAME: sslcrtvalidator_program
2369 LOC: Ssl::TheConfig.ssl_crt_validator
2371 Specify the location and options of the executable for ssl_crt_validator
2375 NAME: sslcrtvalidator_children
2376 TYPE: HelperChildConfig
2378 DEFAULT: 32 startup=5 idle=1
2379 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2381 The maximum number of processes spawn to service ssl server.
2382 The maximum this may be safely set to is 32.
2384 The startup= and idle= options allow some measure of skew in your
2389 Sets the minimum number of processes to spawn when Squid
2390 starts or reconfigures. When set to zero the first request will
2391 cause spawning of the first child process to handle it.
2393 Starting too few children temporary slows Squid under load while it
2394 tries to spawn enough additional processes to cope with traffic.
2398 Sets a minimum of how many processes Squid is to try and keep available
2399 at all times. When traffic begins to rise above what the existing
2400 processes can handle this many more will be spawned up to the maximum
2401 configured. A minimum setting of 1 is required.
2403 You must have at least one ssl_crt_validator process.
2407 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2408 -----------------------------------------------------------------------------
2416 To specify other caches in a hierarchy, use the format:
2418 cache_peer hostname type http-port icp-port [options]
2423 # hostname type port port options
2424 # -------------------- -------- ----- ----- -----------
2425 cache_peer parent.foo.net parent 3128 3130 default
2426 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2427 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2428 cache_peer example.com parent 80 0 default
2429 cache_peer cdn.example.com sibling 3128 0
2431 type: either 'parent', 'sibling', or 'multicast'.
2433 proxy-port: The port number where the peer accept HTTP requests.
2434 For other Squid proxies this is usually 3128
2435 For web servers this is usually 80
2437 icp-port: Used for querying neighbor caches about objects.
2438 Set to 0 if the peer does not support ICP or HTCP.
2439 See ICP and HTCP options below for additional details.
2442 ==== ICP OPTIONS ====
2444 You MUST also set icp_port and icp_access explicitly when using these options.
2445 The defaults will prevent peer traffic using ICP.
2448 no-query Disable ICP queries to this neighbor.
2451 Indicates the named peer is a member of a multicast group.
2452 ICP queries will not be sent directly to the peer, but ICP
2453 replies will be accepted from it.
2455 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2456 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2459 To only send ICP queries to this neighbor infrequently.
2460 This is used to keep the neighbor round trip time updated
2461 and is usually used in conjunction with weighted-round-robin.
2464 ==== HTCP OPTIONS ====
2466 You MUST also set htcp_port and htcp_access explicitly when using these options.
2467 The defaults will prevent peer traffic using HTCP.
2470 htcp Send HTCP, instead of ICP, queries to the neighbor.
2471 You probably also want to set the "icp-port" to 4827
2472 instead of 3130. This directive accepts a comma separated
2473 list of options described below.
2475 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2477 htcp=no-clr Send HTCP to the neighbor but without
2478 sending any CLR requests. This cannot be used with
2481 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2482 This cannot be used with no-clr.
2485 Send HTCP to the neighbor including CLRs but only when
2486 they do not result from PURGE requests.
2489 Forward any HTCP CLR requests this proxy receives to the peer.
2492 ==== PEER SELECTION METHODS ====
2494 The default peer selection method is ICP, with the first responding peer
2495 being used as source. These options can be used for better load balancing.
2498 default This is a parent cache which can be used as a "last-resort"
2499 if a peer cannot be located by any of the peer-selection methods.
2500 If specified more than once, only the first is used.
2502 round-robin Load-Balance parents which should be used in a round-robin
2503 fashion in the absence of any ICP queries.
2504 weight=N can be used to add bias.
2506 weighted-round-robin
2507 Load-Balance parents which should be used in a round-robin
2508 fashion with the frequency of each parent being based on the
2509 round trip time. Closer parents are used more often.
2510 Usually used for background-ping parents.
2511 weight=N can be used to add bias.
2513 carp Load-Balance parents which should be used as a CARP array.
2514 The requests will be distributed among the parents based on the
2515 CARP load balancing hash function based on their weight.
2517 userhash Load-balance parents based on the client proxy_auth or ident username.
2519 sourcehash Load-balance parents based on the client source IP.
2522 To be used only for cache peers of type "multicast".
2523 ALL members of this multicast group have "sibling"
2524 relationship with it, not "parent". This is to a multicast
2525 group when the requested object would be fetched only from
2526 a "parent" cache, anyway. It's useful, e.g., when
2527 configuring a pool of redundant Squid proxies, being
2528 members of the same multicast group.
2531 ==== PEER SELECTION OPTIONS ====
2533 weight=N use to affect the selection of a peer during any weighted
2534 peer-selection mechanisms.
2535 The weight must be an integer; default is 1,
2536 larger weights are favored more.
2537 This option does not affect parent selection if a peering
2538 protocol is not in use.
2540 basetime=N Specify a base amount to be subtracted from round trip
2542 It is subtracted before division by weight in calculating
2543 which parent to fectch from. If the rtt is less than the
2544 base time the rtt is set to a minimal value.
2546 ttl=N Specify a TTL to use when sending multicast ICP queries
2548 Only useful when sending to a multicast group.
2549 Because we don't accept ICP replies from random
2550 hosts, you must configure other group members as
2551 peers with the 'multicast-responder' option.
2553 no-delay To prevent access to this neighbor from influencing the
2556 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2557 enabled) for this host from the specified URL rather
2558 than the Squid default location.
2561 ==== CARP OPTIONS ====
2563 carp-key=key-specification
2564 use a different key than the full URL to hash against the peer.
2565 the key-specification is a comma-separated list of the keywords
2566 scheme, host, port, path, params
2567 Order is not important.
2569 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2571 originserver Causes this parent to be contacted as an origin server.
2572 Meant to be used in accelerator setups when the peer
2576 Set the Host header of requests forwarded to this peer.
2577 Useful in accelerator setups where the server (peer)
2578 expects a certain domain name but clients may request
2579 others. ie example.com or www.example.com
2581 no-digest Disable request of cache digests.
2584 Disables requesting ICMP RTT database (NetDB).
2587 ==== AUTHENTICATION OPTIONS ====
2590 If this is a personal/workgroup proxy and your parent
2591 requires proxy authentication.
2593 Note: The string can include URL escapes (i.e. %20 for
2594 spaces). This also means % must be written as %%.
2597 Send login details received from client to this peer.
2598 Both Proxy- and WWW-Authorization headers are passed
2599 without alteration to the peer.
2600 Authentication is not required by Squid for this to work.
2602 Note: This will pass any form of authentication but
2603 only Basic auth will work through a proxy unless the
2604 connection-auth options are also used.
2606 login=PASS Send login details received from client to this peer.
2607 Authentication is not required by this option.
2609 If there are no client-provided authentication headers
2610 to pass on, but username and password are available
2611 from an external ACL user= and password= result tags
2612 they may be sent instead.
2614 Note: To combine this with proxy_auth both proxies must
2615 share the same user database as HTTP only allows for
2616 a single login (one for proxy, one for origin server).
2617 Also be warned this will expose your users proxy
2618 password to the peer. USE WITH CAUTION
2621 Send the username to the upstream cache, but with a
2622 fixed password. This is meant to be used when the peer
2623 is in another administrative domain, but it is still
2624 needed to identify each user.
2625 The star can optionally be followed by some extra
2626 information which is added to the username. This can
2627 be used to identify this proxy to the peer, similar to
2628 the login=username:password option above.
2631 If this is a personal/workgroup proxy and your parent
2632 requires a secure proxy authentication.
2633 The first principal from the default keytab or defined by
2634 the environment variable KRB5_KTNAME will be used.
2636 WARNING: The connection may transmit requests from multiple
2637 clients. Negotiate often assumes end-to-end authentication
2638 and a single-client. Which is not strictly true here.
2640 login=NEGOTIATE:principal_name
2641 If this is a personal/workgroup proxy and your parent
2642 requires a secure proxy authentication.
2643 The principal principal_name from the default keytab or
2644 defined by the environment variable KRB5_KTNAME will be
2647 WARNING: The connection may transmit requests from multiple
2648 clients. Negotiate often assumes end-to-end authentication
2649 and a single-client. Which is not strictly true here.
2651 connection-auth=on|off
2652 Tell Squid that this peer does or not support Microsoft
2653 connection oriented authentication, and any such
2654 challenges received from there should be ignored.
2655 Default is auto to automatically determine the status
2659 ==== SSL / HTTPS / TLS OPTIONS ====
2661 ssl Encrypt connections to this peer with SSL/TLS.
2663 sslcert=/path/to/ssl/certificate
2664 A client SSL certificate to use when connecting to
2667 sslkey=/path/to/ssl/key
2668 The private SSL key corresponding to sslcert above.
2669 If 'sslkey' is not specified 'sslcert' is assumed to
2670 reference a combined file containing both the
2671 certificate and the key.
2673 sslversion=1|2|3|4|5|6
2674 The SSL version to use when connecting to this peer
2675 1 = automatic (default)
2682 sslcipher=... The list of valid SSL ciphers to use when connecting
2685 ssloptions=... Specify various SSL implementation options:
2687 NO_SSLv2 Disallow the use of SSLv2
2688 NO_SSLv3 Disallow the use of SSLv3
2689 NO_TLSv1 Disallow the use of TLSv1.0
2690 NO_TLSv1_1 Disallow the use of TLSv1.1
2691 NO_TLSv1_2 Disallow the use of TLSv1.2
2693 Always create a new key when using
2694 temporary/ephemeral DH key exchanges
2695 ALL Enable various bug workarounds
2696 suggested as "harmless" by OpenSSL
2697 Be warned that this reduces SSL/TLS
2698 strength to some attacks.
2700 See the OpenSSL SSL_CTX_set_options documentation for a
2703 sslcafile=... A file containing additional CA certificates to use
2704 when verifying the peer certificate.
2706 sslcapath=... A directory containing additional CA certificates to
2707 use when verifying the peer certificate.
2709 sslcrlfile=... A certificate revocation list file to use when
2710 verifying the peer certificate.
2712 sslflags=... Specify various flags modifying the SSL implementation:
2715 Accept certificates even if they fail to
2718 Don't use the default CA list built in
2721 Don't verify the peer certificate
2722 matches the server name
2724 ssldomain= The peer name as advertised in it's certificate.
2725 Used for verifying the correctness of the received peer
2726 certificate. If not specified the peer hostname will be
2730 Enable the "Front-End-Https: On" header needed when
2731 using Squid as a SSL frontend in front of Microsoft OWA.
2732 See MS KB document Q307347 for details on this header.
2733 If set to auto the header will only be added if the
2734 request is forwarded as a https:// URL.
2737 ==== GENERAL OPTIONS ====
2740 A peer-specific connect timeout.
2741 Also see the peer_connect_timeout directive.
2743 connect-fail-limit=N
2744 How many times connecting to a peer must fail before
2745 it is marked as down. Default is 10.
2747 allow-miss Disable Squid's use of only-if-cached when forwarding
2748 requests to siblings. This is primarily useful when
2749 icp_hit_stale is used by the sibling. To extensive use
2750 of this option may result in forwarding loops, and you
2751 should avoid having two-way peerings with this option.
2752 For example to deny peer usage on requests from peer
2753 by denying cache_peer_access if the source is a peer.
2755 max-conn=N Limit the amount of connections Squid may open to this
2758 name=xxx Unique name for the peer.
2759 Required if you have multiple peers on the same host
2760 but different ports.
2761 This name can be used in cache_peer_access and similar
2762 directives to dentify the peer.
2763 Can be used by outgoing access controls through the
2766 no-tproxy Do not use the client-spoof TPROXY support when forwarding
2767 requests to this peer. Use normal address selection instead.
2769 proxy-only objects fetched from the peer will not be stored locally.
2773 NAME: cache_peer_domain cache_host_domain
2778 Use to limit the domains for which a neighbor cache will be
2781 cache_peer_domain cache-host domain [domain ...]
2782 cache_peer_domain cache-host !domain
2784 For example, specifying
2786 cache_peer_domain parent.foo.net .edu
2788 has the effect such that UDP query packets are sent to
2789 'bigserver' only when the requested object exists on a
2790 server in the .edu domain. Prefixing the domainname
2791 with '!' means the cache will be queried for objects
2794 NOTE: * Any number of domains may be given for a cache-host,
2795 either on the same or separate lines.
2796 * When multiple domains are given for a particular
2797 cache-host, the first matched domain is applied.
2798 * Cache hosts with no domain restrictions are queried
2800 * There are no defaults.
2801 * There is also a 'cache_peer_access' tag in the ACL
2805 NAME: cache_peer_access
2810 Similar to 'cache_peer_domain' but provides more flexibility by
2813 cache_peer_access cache-host allow|deny [!]aclname ...
2815 The syntax is identical to 'http_access' and the other lists of
2816 ACL elements. See the comments for 'http_access' below, or
2817 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
2820 NAME: neighbor_type_domain
2821 TYPE: hostdomaintype
2825 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
2827 Modifying the neighbor type for specific domains is now
2828 possible. You can treat some domains differently than the
2829 default neighbor type specified on the 'cache_peer' line.
2830 Normally it should only be necessary to list domains which
2831 should be treated differently because the default neighbor type
2832 applies for hostnames which do not match domains listed here.
2835 cache_peer cache.foo.org parent 3128 3130
2836 neighbor_type_domain cache.foo.org sibling .com .net
2837 neighbor_type_domain cache.foo.org sibling .au .de
2840 NAME: dead_peer_timeout
2844 LOC: Config.Timeout.deadPeer
2846 This controls how long Squid waits to declare a peer cache
2847 as "dead." If there are no ICP replies received in this
2848 amount of time, Squid will declare the peer dead and not
2849 expect to receive any further ICP replies. However, it
2850 continues to send ICP queries, and will mark the peer as
2851 alive upon receipt of the first subsequent ICP reply.
2853 This timeout also affects when Squid expects to receive ICP
2854 replies from peers. If more than 'dead_peer' seconds have
2855 passed since the last ICP reply was received, Squid will not
2856 expect to receive an ICP reply on the next query. Thus, if
2857 your time between requests is greater than this timeout, you
2858 will see a lot of requests sent DIRECT to origin servers
2859 instead of to your parents.
2862 NAME: forward_max_tries
2865 LOC: Config.forward_max_tries
2867 Controls how many different forward paths Squid will try
2868 before giving up. See also forward_timeout.
2870 NOTE: connect_retries (default: none) can make each of these
2871 possible forwarding paths be tried multiple times.
2874 NAME: hierarchy_stoplist
2877 LOC: Config.hierarchy_stoplist
2879 A list of words which, if found in a URL, cause the object to
2880 be handled directly by this cache. In other words, use this
2881 to not query neighbor caches for certain objects. You may
2882 list this option multiple times.
2885 hierarchy_stoplist cgi-bin ?
2887 Note: never_direct overrides this option.
2891 MEMORY CACHE OPTIONS
2892 -----------------------------------------------------------------------------
2899 LOC: Config.memMaxSize
2901 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
2902 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
2903 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
2904 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
2906 'cache_mem' specifies the ideal amount of memory to be used
2908 * In-Transit objects
2910 * Negative-Cached objects
2912 Data for these objects are stored in 4 KB blocks. This
2913 parameter specifies the ideal upper limit on the total size of
2914 4 KB blocks allocated. In-Transit objects take the highest
2917 In-transit objects have priority over the others. When
2918 additional space is needed for incoming data, negative-cached
2919 and hot objects will be released. In other words, the
2920 negative-cached and hot objects will fill up any unused space
2921 not needed for in-transit objects.
2923 If circumstances require, this limit will be exceeded.
2924 Specifically, if your incoming request rate requires more than
2925 'cache_mem' of memory to hold in-transit objects, Squid will
2926 exceed this limit to satisfy the new requests. When the load
2927 decreases, blocks will be freed until the high-water mark is
2928 reached. Thereafter, blocks will be used to store hot
2931 If shared memory caching is enabled, Squid does not use the shared
2932 cache space for in-transit objects, but they still consume as much
2933 local memory as they need. For more details about the shared memory
2934 cache, see memory_cache_shared.
2937 NAME: maximum_object_size_in_memory
2941 LOC: Config.Store.maxInMemObjSize
2943 Objects greater than this size will not be attempted to kept in
2944 the memory cache. This should be set high enough to keep objects
2945 accessed frequently in memory to improve performance whilst low
2946 enough to keep larger objects from hoarding cache_mem.
2949 NAME: memory_cache_shared
2952 LOC: Config.memShared
2954 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
2956 Controls whether the memory cache is shared among SMP workers.
2958 The shared memory cache is meant to occupy cache_mem bytes and replace
2959 the non-shared memory cache, although some entities may still be
2960 cached locally by workers for now (e.g., internal and in-transit
2961 objects may be served from a local memory cache even if shared memory
2962 caching is enabled).
2964 By default, the memory cache is shared if and only if all of the
2965 following conditions are satisfied: Squid runs in SMP mode with
2966 multiple workers, cache_mem is positive, and Squid environment
2967 supports required IPC primitives (e.g., POSIX shared memory segments
2968 and GCC-style atomic operations).
2970 To avoid blocking locks, shared memory uses opportunistic algorithms
2971 that do not guarantee that every cachable entity that could have been
2972 shared among SMP workers will actually be shared.
2974 Currently, entities exceeding 32KB in size cannot be shared.
2977 NAME: memory_cache_mode
2982 Controls which objects to keep in the memory cache (cache_mem)
2984 always Keep most recently fetched objects in memory (default)
2986 disk Only disk cache hits are kept in memory, which means
2987 an object must first be cached on disk and then hit
2988 a second time before cached in memory.
2990 network Only objects fetched from network is kept in memory
2993 NAME: memory_replacement_policy
2995 LOC: Config.memPolicy
2998 The memory replacement policy parameter determines which
2999 objects are purged from memory when memory space is needed.
3001 See cache_replacement_policy for details.
3006 -----------------------------------------------------------------------------
3009 NAME: cache_replacement_policy
3011 LOC: Config.replPolicy
3014 The cache replacement policy parameter determines which
3015 objects are evicted (replaced) when disk space is needed.
3017 lru : Squid's original list based LRU policy
3018 heap GDSF : Greedy-Dual Size Frequency
3019 heap LFUDA: Least Frequently Used with Dynamic Aging
3020 heap LRU : LRU policy implemented using a heap
3022 Applies to any cache_dir lines listed below this.
3024 The LRU policies keeps recently referenced objects.
3026 The heap GDSF policy optimizes object hit rate by keeping smaller
3027 popular objects in cache so it has a better chance of getting a
3028 hit. It achieves a lower byte hit rate than LFUDA though since
3029 it evicts larger (possibly popular) objects.
3031 The heap LFUDA policy keeps popular objects in cache regardless of
3032 their size and thus optimizes byte hit rate at the expense of
3033 hit rate since one large, popular object will prevent many
3034 smaller, slightly less popular objects from being cached.
3036 Both policies utilize a dynamic aging mechanism that prevents
3037 cache pollution that can otherwise occur with frequency-based
3038 replacement policies.
3040 NOTE: if using the LFUDA replacement policy you should increase
3041 the value of maximum_object_size above its default of 4096 KB to
3042 to maximize the potential byte hit rate improvement of LFUDA.
3044 For more information about the GDSF and LFUDA cache replacement
3045 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3046 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3052 LOC: Config.cacheSwap
3056 cache_dir Type Directory-Name Fs-specific-data [options]
3058 You can specify multiple cache_dir lines to spread the
3059 cache among different disk partitions.
3061 Type specifies the kind of storage system to use. Only "ufs"
3062 is built by default. To enable any of the other storage systems
3063 see the --enable-storeio configure option.
3065 'Directory' is a top-level directory where cache swap
3066 files will be stored. If you want to use an entire disk
3067 for caching, this can be the mount-point directory.
3068 The directory must exist and be writable by the Squid
3069 process. Squid will NOT create this directory for you.
3071 In SMP configurations, cache_dir must not precede the workers option
3072 and should use configuration macros or conditionals to give each
3073 worker interested in disk caching a dedicated cache directory.
3077 "ufs" is the old well-known Squid storage format that has always
3080 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3082 'Mbytes' is the amount of disk space (MB) to use under this
3083 directory. The default is 100 MB. Change this to suit your
3084 configuration. Do NOT put the size of your disk drive here.
3085 Instead, if you want Squid to use the entire disk drive,
3086 subtract 20% and use that value.
3088 'L1' is the number of first-level subdirectories which
3089 will be created under the 'Directory'. The default is 16.
3091 'L2' is the number of second-level subdirectories which
3092 will be created under each first-level directory. The default
3095 The aufs store type:
3097 "aufs" uses the same storage format as "ufs", utilizing
3098 POSIX-threads to avoid blocking the main Squid process on
3099 disk-I/O. This was formerly known in Squid as async-io.
3101 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3103 see argument descriptions under ufs above
3105 The diskd store type:
3107 "diskd" uses the same storage format as "ufs", utilizing a
3108 separate process to avoid blocking the main Squid process on
3111 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3113 see argument descriptions under ufs above
3115 Q1 specifies the number of unacknowledged I/O requests when Squid
3116 stops opening new files. If this many messages are in the queues,
3117 Squid won't open new files. Default is 64
3119 Q2 specifies the number of unacknowledged messages when Squid
3120 starts blocking. If this many messages are in the queues,
3121 Squid blocks until it receives some replies. Default is 72
3123 When Q1 < Q2 (the default), the cache directory is optimized
3124 for lower response time at the expense of a decrease in hit
3125 ratio. If Q1 > Q2, the cache directory is optimized for
3126 higher hit ratio at the expense of an increase in response
3129 The rock store type:
3131 cache_dir rock Directory-Name Mbytes <max-size=bytes> [options]
3133 The Rock Store type is a database-style storage. All cached
3134 entries are stored in a "database" file, using fixed-size slots,
3135 one entry per slot. The database size is specified in MB. The
3136 slot size is specified in bytes using the max-size option. See
3137 below for more info on the max-size option.
3139 swap-timeout=msec: Squid will not start writing a miss to or
3140 reading a hit from disk if it estimates that the swap operation
3141 will take more than the specified number of milliseconds. By
3142 default and when set to zero, disables the disk I/O time limit
3143 enforcement. Ignored when using blocking I/O module because
3144 blocking synchronous I/O does not allow Squid to estimate the
3145 expected swap wait time.
3147 max-swap-rate=swaps/sec: Artificially limits disk access using
3148 the specified I/O rate limit. Swap out requests that
3149 would cause the average I/O rate to exceed the limit are
3150 delayed. Individual swap in requests (i.e., hits or reads) are
3151 not delayed, but they do contribute to measured swap rate and
3152 since they are placed in the same FIFO queue as swap out
3153 requests, they may wait longer if max-swap-rate is smaller.
3154 This is necessary on file systems that buffer "too
3155 many" writes and then start blocking Squid and other processes
3156 while committing those writes to disk. Usually used together
3157 with swap-timeout to avoid excessive delays and queue overflows
3158 when disk demand exceeds available disk "bandwidth". By default
3159 and when set to zero, disables the disk I/O rate limit
3160 enforcement. Currently supported by IpcIo module only.
3163 The coss store type:
3165 NP: COSS filesystem in Squid-3 has been deemed too unstable for
3166 production use and has thus been removed from this release.
3167 We hope that it can be made usable again soon.
3169 block-size=n defines the "block size" for COSS cache_dir's.
3170 Squid uses file numbers as block numbers. Since file numbers
3171 are limited to 24 bits, the block size determines the maximum
3172 size of the COSS partition. The default is 512 bytes, which
3173 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
3174 you should not change the coss block size after Squid
3175 has written some objects to the cache_dir.
3177 The coss file store has changed from 2.5. Now it uses a file
3178 called 'stripe' in the directory names in the config - and
3179 this will be created by squid -z.
3183 no-store, no new objects should be stored to this cache_dir
3185 min-size=n, refers to the min object size in bytes this cache_dir
3186 will accept. It's used to restrict a cache_dir to only store
3187 large objects (e.g. aufs) while other storedirs are optimized
3188 for smaller objects (e.g. COSS). Defaults to 0.
3190 max-size=n, refers to the max object size in bytes this cache_dir
3191 supports. It is used to select the cache_dir to store the object.
3192 Note: To make optimal use of the max-size limits you should order
3193 the cache_dir lines with the smallest max-size value first and the
3194 ones with no max-size specification last.
3196 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
3197 which can be changed with the --with-coss-membuf-size=N configure
3201 # Uncomment and adjust the following to add a disk cache directory.
3202 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3206 NAME: store_dir_select_algorithm
3208 LOC: Config.store_dir_select_algorithm
3211 Set this to 'round-robin' as an alternative.
3214 NAME: max_open_disk_fds
3216 LOC: Config.max_open_disk_fds
3219 To avoid having disk as the I/O bottleneck Squid can optionally
3220 bypass the on-disk cache if more than this amount of disk file
3221 descriptors are open.
3223 A value of 0 indicates no limit.
3226 NAME: minimum_object_size
3230 LOC: Config.Store.minObjectSize
3232 Objects smaller than this size will NOT be saved on disk. The
3233 value is specified in kilobytes, and the default is 0 KB, which
3234 means there is no minimum.
3237 NAME: maximum_object_size
3241 LOC: Config.Store.maxObjectSize
3243 Objects larger than this size will NOT be saved on disk. The
3244 value is specified in kilobytes, and the default is 4MB. If
3245 you wish to get a high BYTES hit ratio, you should probably
3246 increase this (one 32 MB object hit counts for 3200 10KB
3247 hits). If you wish to increase speed more than your want to
3248 save bandwidth you should leave this low.
3250 NOTE: if using the LFUDA replacement policy you should increase
3251 this value to maximize the byte hit rate improvement of LFUDA!
3252 See replacement_policy below for a discussion of this policy.
3255 NAME: cache_swap_low
3256 COMMENT: (percent, 0-100)
3259 LOC: Config.Swap.lowWaterMark
3262 NAME: cache_swap_high
3263 COMMENT: (percent, 0-100)
3266 LOC: Config.Swap.highWaterMark
3269 The low- and high-water marks for cache object replacement.
3270 Replacement begins when the swap (disk) usage is above the
3271 low-water mark and attempts to maintain utilization near the
3272 low-water mark. As swap utilization gets close to high-water
3273 mark object eviction becomes more aggressive. If utilization is
3274 close to the low-water mark less replacement is done each time.
3276 Defaults are 90% and 95%. If you have a large cache, 5% could be
3277 hundreds of MB. If this is the case you may wish to set these
3278 numbers closer together.
3283 -----------------------------------------------------------------------------
3293 logformat <name> <format specification>
3295 Defines an access log format.
3297 The <format specification> is a string with embedded % format codes
3299 % format codes all follow the same basic structure where all but
3300 the formatcode is optional. Output strings are automatically escaped
3301 as required according to their context and the output format
3302 modifiers are usually not needed, but can be specified if an explicit
3303 output format is desired.
3305 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3307 " output in quoted string format
3308 [ output in squid text log format as used by log_mime_hdrs
3309 # output in URL quoted format
3314 width minimum and/or maximum field width:
3315 [width_min][.width_max]
3316 When minimum starts with 0, the field is zero-padded.
3317 String values exceeding maximum width are truncated.
3319 {arg} argument such as header name etc
3323 % a literal % character
3324 sn Unique sequence number per log line entry
3325 err_code The ID of an error response served by Squid or
3326 a similar internal error identifier.
3327 err_detail Additional err_code-dependent error information.
3328 note The meta header specified by the argument. Also
3329 logs the adaptation meta headers set by the
3330 adaptation_meta configuration parameter.
3331 If no argument given all meta headers logged.
3333 Connection related format codes:
3335 >a Client source IP address
3337 >p Client source port
3338 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3339 >la Local IP address the client connected to
3340 >lp Local port number the client connected to
3342 la Local listening IP address the client connection was connected to.
3343 lp Local listening port number the client connection was connected to.
3345 <a Server IP address of the last server or peer connection
3346 <A Server FQDN or peer name
3347 <p Server port number of the last server or peer connection
3348 <la Local IP address of the last server or peer connection
3349 <lp Local port number of the last server or peer connection
3351 Time related format codes:
3353 ts Seconds since epoch
3354 tu subsecond time (milliseconds)
3355 tl Local time. Optional strftime format argument
3356 default %d/%b/%Y:%H:%M:%S %z
3357 tg GMT time. Optional strftime format argument
3358 default %d/%b/%Y:%H:%M:%S %z
3359 tr Response time (milliseconds)
3360 dt Total time spent making DNS lookups (milliseconds)
3362 Access Control related format codes:
3364 et Tag returned by external acl
3365 ea Log string returned by external acl
3366 un User name (any available)
3367 ul User name from authentication
3368 ue User name from external acl helper
3369 ui User name from ident
3370 us User name from SSL
3372 HTTP related format codes:
3374 [http::]>h Original request header. Optional header name argument
3375 on the format header[:[separator]element]
3376 [http::]>ha The HTTP request headers after adaptation and redirection.
3377 Optional header name argument as for >h
3378 [http::]<h Reply header. Optional header name argument
3380 [http::]>Hs HTTP status code sent to the client
3381 [http::]<Hs HTTP status code received from the next hop
3382 [http::]<bs Number of HTTP-equivalent message body bytes
3383 received from the next hop, excluding chunked
3384 transfer encoding and control messages.
3385 Generated FTP/Gopher listings are treated as
3387 [http::]mt MIME content type
3388 [http::]rm Request method (GET/POST etc)
3389 [http::]>rm Request method from client
3390 [http::]<rm Request method sent to server or peer
3391 [http::]ru Request URL from client (historic, filtered for logging)
3392 [http::]>ru Request URL from client
3393 [http::]<ru Request URL sent to server or peer
3394 [http::]rp Request URL-Path excluding hostname
3395 [http::]>rp Request URL-Path excluding hostname from client
3396 [http::]<rp Request URL-Path excluding hostname sento to server or peer
3397 [http::]rv Request protocol version
3398 [http::]>rv Request protocol version from client
3399 [http::]<rv Request protocol version sent to server or peer
3400 [http::]<st Sent reply size including HTTP headers
3401 [http::]>st Received request size including HTTP headers. In the
3402 case of chunked requests the chunked encoding metadata
3404 [http::]>sh Received HTTP request headers size
3405 [http::]<sh Sent HTTP reply headers size
3406 [http::]st Request+Reply size including HTTP headers
3407 [http::]<sH Reply high offset sent
3408 [http::]<sS Upstream object size
3409 [http::]<pt Peer response time in milliseconds. The timer starts
3410 when the last request byte is sent to the next hop
3411 and stops when the last response byte is received.
3412 [http::]<tt Total server-side time in milliseconds. The timer
3413 starts with the first connect request (or write I/O)
3414 sent to the first selected peer. The timer stops
3415 with the last I/O with the last peer.
3417 Squid handling related format codes:
3419 Ss Squid request status (TCP_MISS etc)
3420 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3422 SSL-related format codes:
3424 ssl::bump_mode SslBump decision for the transaction:
3426 For CONNECT requests that initiated bumping of
3427 a connection and for any request received on
3428 an already bumped connection, Squid logs the
3429 corresponding SslBump mode ("server-first" or
3430 "client-first"). See the ssl_bump option for
3431 more information about these modes.
3433 A "none" token is logged for requests that
3434 triggered "ssl_bump" ACL evaluation matching
3435 either a "none" rule or no rules at all.
3437 In all other cases, a single dash ("-") is
3440 If ICAP is enabled, the following code becomes available (as
3441 well as ICAP log codes documented with the icap_log option):
3443 icap::tt Total ICAP processing time for the HTTP
3444 transaction. The timer ticks when ICAP
3445 ACLs are checked and when ICAP
3446 transaction is in progress.
3448 If adaptation is enabled the following three codes become available:
3450 adapt::<last_h The header of the last ICAP response or
3451 meta-information from the last eCAP
3452 transaction related to the HTTP transaction.
3453 Like <h, accepts an optional header name
3456 adapt::sum_trs Summed adaptation transaction response
3457 times recorded as a comma-separated list in
3458 the order of transaction start time. Each time
3459 value is recorded as an integer number,
3460 representing response time of one or more
3461 adaptation (ICAP or eCAP) transaction in
3462 milliseconds. When a failed transaction is
3463 being retried or repeated, its time is not
3464 logged individually but added to the
3465 replacement (next) transaction. See also:
3468 adapt::all_trs All adaptation transaction response times.
3469 Same as adaptation_strs but response times of
3470 individual transactions are never added
3471 together. Instead, all transaction response
3472 times are recorded individually.
3474 You can prefix adapt::*_trs format codes with adaptation
3475 service name in curly braces to record response time(s) specific
3476 to that service. For example: %{my_service}adapt::sum_trs
3478 If SSL is enabled, the following formating codes become available:
3480 %ssl::>cert_subject The Subject field of the received client
3481 SSL certificate or a dash ('-') if Squid has
3482 received an invalid/malformed certificate or
3483 no certificate at all. Consider encoding the
3484 logged value because Subject often has spaces.
3486 %ssl::>cert_issuer The Issuer field of the received client
3487 SSL certificate or a dash ('-') if Squid has
3488 received an invalid/malformed certificate or
3489 no certificate at all. Consider encoding the
3490 logged value because Issuer often has spaces.
3492 The default formats available (which do not need re-defining) are:
3494 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3495 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3496 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3497 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3498 logformat useragent %>a [%tl] "%{User-Agent}>h"
3500 NOTE: When the log_mime_hdrs directive is set to ON.
3501 The squid, common and combined formats have a safely encoded copy
3502 of the mime headers appended to each line within a pair of brackets.
3504 NOTE: The common and combined formats are not quite true to the Apache definition.
3505 The logs from Squid contain an extra status and hierarchy code appended.
3509 NAME: access_log cache_access_log
3511 LOC: Config.Log.accesslogs
3512 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3514 These files log client request activities. Has a line every HTTP or
3515 ICP request. The format is:
3516 access_log <module>:<place> [<logformat name> [acl acl ...]]
3517 access_log none [acl acl ...]]
3519 Will log to the specified module:place using the specified format (which
3520 must be defined in a logformat directive) those entries which match
3521 ALL the acl's specified (which must be defined in acl clauses).
3522 If no acl is specified, all requests will be logged to this destination.
3524 ===== Modules Currently available =====
3526 none Do not log any requests matching these ACL.
3527 Do not specify Place or logformat name.
3529 stdio Write each log line to disk immediately at the completion of
3531 Place: the filename and path to be written.
3533 daemon Very similar to stdio. But instead of writing to disk the log
3534 line is passed to a daemon helper for asychronous handling instead.
3535 Place: varies depending on the daemon.
3537 log_file_daemon Place: the file name and path to be written.
3539 syslog To log each request via syslog facility.
3540 Place: The syslog facility and priority level for these entries.
3541 Place Format: facility.priority
3543 where facility could be any of:
3544 authpriv, daemon, local0 ... local7 or user.
3546 And priority could be any of:
3547 err, warning, notice, info, debug.
3549 udp To send each log line as text data to a UDP receiver.
3550 Place: The destination host name or IP and port.
3551 Place Format: //host:port
3553 tcp To send each log line as text data to a TCP receiver.
3554 Place: The destination host name or IP and port.
3555 Place Format: //host:port
3558 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3564 LOC: Config.Log.icaplogs
3567 ICAP log files record ICAP transaction summaries, one line per
3570 The icap_log option format is:
3571 icap_log <filepath> [<logformat name> [acl acl ...]]
3572 icap_log none [acl acl ...]]
3574 Please see access_log option documentation for details. The two
3575 kinds of logs share the overall configuration approach and many
3578 ICAP processing of a single HTTP message or transaction may
3579 require multiple ICAP transactions. In such cases, multiple
3580 ICAP transaction log lines will correspond to a single access
3583 ICAP log uses logformat codes that make sense for an ICAP
3584 transaction. Header-related codes are applied to the HTTP header
3585 embedded in an ICAP server response, with the following caveats:
3586 For REQMOD, there is no HTTP response header unless the ICAP
3587 server performed request satisfaction. For RESPMOD, the HTTP
3588 request header is the header sent to the ICAP server. For
3589 OPTIONS, there are no HTTP headers.
3591 The following format codes are also available for ICAP logs:
3593 icap::<A ICAP server IP address. Similar to <A.
3595 icap::<service_name ICAP service name from the icap_service
3596 option in Squid configuration file.
3598 icap::ru ICAP Request-URI. Similar to ru.
3600 icap::rm ICAP request method (REQMOD, RESPMOD, or
3601 OPTIONS). Similar to existing rm.
3603 icap::>st Bytes sent to the ICAP server (TCP payload
3604 only; i.e., what Squid writes to the socket).
3606 icap::<st Bytes received from the ICAP server (TCP
3607 payload only; i.e., what Squid reads from
3610 icap::<bs Number of message body bytes received from the
3611 ICAP server. ICAP message body, if any, usually
3612 includes encapsulated HTTP message headers and
3613 possibly encapsulated HTTP message body. The
3614 HTTP body part is dechunked before its size is
3617 icap::tr Transaction response time (in
3618 milliseconds). The timer starts when
3619 the ICAP transaction is created and
3620 stops when the transaction is completed.
3623 icap::tio Transaction I/O time (in milliseconds). The
3624 timer starts when the first ICAP request
3625 byte is scheduled for sending. The timers
3626 stops when the last byte of the ICAP response
3629 icap::to Transaction outcome: ICAP_ERR* for all
3630 transaction errors, ICAP_OPT for OPTION
3631 transactions, ICAP_ECHO for 204
3632 responses, ICAP_MOD for message
3633 modification, and ICAP_SAT for request
3634 satisfaction. Similar to Ss.
3636 icap::Hs ICAP response status code. Similar to Hs.
3638 icap::>h ICAP request header(s). Similar to >h.
3640 icap::<h ICAP response header(s). Similar to <h.
3642 The default ICAP log format, which can be used without an explicit
3643 definition, is called icap_squid:
3645 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3647 See also: logformat, log_icap, and %adapt::<last_h
3650 NAME: logfile_daemon
3652 DEFAULT: @DEFAULT_LOGFILED@
3653 LOC: Log::TheConfig.logfile_daemon
3655 Specify the path to the logfile-writing daemon. This daemon is
3656 used to write the access and store logs, if configured.
3658 Squid sends a number of commands to the log daemon:
3659 L<data>\n - logfile data
3664 r<n>\n - set rotate count to <n>
3665 b<n>\n - 1 = buffer output, 0 = don't buffer output
3667 No responses is expected.
3672 LOC: Config.accessList.log
3674 COMMENT: allow|deny acl acl...
3676 This options allows you to control which requests gets logged
3677 to access.log (see access_log directive). Requests denied for
3678 logging will also not be accounted for in performance counters.
3680 This clause only supports fast acl types.
3681 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3687 LOC: Config.accessList.icap
3690 This options allows you to control which requests get logged
3691 to icap.log. See the icap_log directive for ICAP log details.
3694 NAME: cache_store_log
3697 LOC: Config.Log.store
3699 Logs the activities of the storage manager. Shows which
3700 objects are ejected from the cache, and which objects are
3701 saved and for how long.
3702 There are not really utilities to analyze this data, so you can safely
3703 disable it (the default).
3705 Store log uses modular logging outputs. See access_log for the list
3706 of modules supported.
3709 cache_store_log stdio:@DEFAULT_STORE_LOG@
3710 cache_store_log daemon:@DEFAULT_STORE_LOG@
3713 NAME: cache_swap_state cache_swap_log
3715 LOC: Config.Log.swap
3718 Location for the cache "swap.state" file. This index file holds
3719 the metadata of objects saved on disk. It is used to rebuild
3720 the cache during startup. Normally this file resides in each
3721 'cache_dir' directory, but you may specify an alternate
3722 pathname here. Note you must give a full filename, not just
3723 a directory. Since this is the index for the whole object
3724 list you CANNOT periodically rotate it!
3726 If %s can be used in the file name it will be replaced with a
3727 a representation of the cache_dir name where each / is replaced
3728 with '.'. This is needed to allow adding/removing cache_dir
3729 lines when cache_swap_log is being used.
3731 If have more than one 'cache_dir', and %s is not used in the name
3732 these swap logs will have names such as:
3738 The numbered extension (which is added automatically)
3739 corresponds to the order of the 'cache_dir' lines in this
3740 configuration file. If you change the order of the 'cache_dir'
3741 lines in this file, these index files will NOT correspond to
3742 the correct 'cache_dir' entry (unless you manually rename
3743 them). We recommend you do NOT use this option. It is
3744 better to keep these index files in each 'cache_dir' directory.
3747 NAME: logfile_rotate
3750 LOC: Config.Log.rotateNumber
3752 Specifies the number of logfile rotations to make when you
3753 type 'squid -k rotate'. The default is 10, which will rotate
3754 with extensions 0 through 9. Setting logfile_rotate to 0 will
3755 disable the file name rotation, but the logfiles are still closed
3756 and re-opened. This will enable you to rename the logfiles
3757 yourself just before sending the rotate signal.
3759 Note, the 'squid -k rotate' command normally sends a USR1
3760 signal to the running squid process. In certain situations
3761 (e.g. on Linux with Async I/O), USR1 is used for other
3762 purposes, so -k rotate uses another signal. It is best to get
3763 in the habit of using 'squid -k rotate' instead of 'kill -USR1
3766 Note, from Squid-3.1 this option has no effect on the cache.log,
3767 that log can be rotated separately by using debug_options
3770 NAME: emulate_httpd_log
3773 Replace this with an access_log directive using the format 'common' or 'combined'.
3776 NAME: log_ip_on_direct
3779 Remove this option from your config. To log server or peer names use %<A in the log format.
3784 DEFAULT: @DEFAULT_MIME_TABLE@
3785 LOC: Config.mimeTablePathname
3787 Pathname to Squid's MIME table. You shouldn't need to change
3788 this, but the default file contains examples and formatting
3789 information if you do.
3795 LOC: Config.onoff.log_mime_hdrs
3798 The Cache can record both the request and the response MIME
3799 headers for each HTTP transaction. The headers are encoded
3800 safely and will appear as two bracketed fields at the end of
3801 the access log (for either the native or httpd-emulated log
3802 formats). To enable this logging set log_mime_hdrs to 'on'.
3808 Replace this with an access_log directive using the format 'useragent'.
3811 NAME: referer_log referrer_log
3814 Replace this with an access_log directive using the format 'referrer'.
3819 DEFAULT: @DEFAULT_PID_FILE@
3820 LOC: Config.pidFilename
3822 A filename to write the process-id to. To disable, enter "none".
3828 Remove this option from your config. To log FQDN use %>A in the log format.
3831 NAME: client_netmask
3833 LOC: Config.Addrs.client_netmask
3836 A netmask for client addresses in logfiles and cachemgr output.
3837 Change this to protect the privacy of your cache clients.
3838 A netmask of 255.255.255.0 will log all IP's in that range with
3839 the last digit set to '0'.
3845 Use a regular access.log with ACL limiting it to MISS events.
3848 NAME: strip_query_terms
3850 LOC: Config.onoff.strip_query_terms
3853 By default, Squid strips query terms from requested URLs before
3854 logging. This protects your user's privacy.
3861 LOC: Config.onoff.buffered_logs
3863 cache.log log file is written with stdio functions, and as such
3864 it can be buffered or unbuffered. By default it will be unbuffered.
3865 Buffering it can speed up the writing slightly (though you are
3866 unlikely to need to worry unless you run with tons of debugging
3867 enabled in which case performance will suffer badly anyway..).
3870 NAME: netdb_filename
3872 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
3873 LOC: Config.netdbFilename
3876 A filename where Squid stores it's netdb state between restarts.
3877 To disable, enter "none".
3881 OPTIONS FOR TROUBLESHOOTING
3882 -----------------------------------------------------------------------------
3887 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
3888 LOC: Debug::cache_log
3890 Cache logging file. This is where general information about
3891 your cache's behavior goes. You can increase the amount of data
3892 logged to this file and how often its rotated with "debug_options"
3898 LOC: Debug::debugOptions
3900 Logging options are set as section,level where each source file
3901 is assigned a unique section. Lower levels result in less
3902 output, Full debugging (level 9) can result in a very large
3903 log file, so be careful.
3905 The magic word "ALL" sets debugging levels for all sections.
3906 We recommend normally running with "ALL,1".
3908 The rotate=N option can be used to keep more or less of these logs
3909 than would otherwise be kept by logfile_rotate.
3910 For most uses a single log should be enough to monitor current
3911 events affecting Squid.
3916 LOC: Config.coredump_dir
3917 DEFAULT_IF_NONE: none
3919 By default Squid leaves core files in the directory from where
3920 it was started. If you set 'coredump_dir' to a directory
3921 that exists, Squid will chdir() to that directory at startup
3922 and coredump files will be left there.
3926 # Leave coredumps in the first cache dir
3927 coredump_dir @DEFAULT_SWAP_DIR@
3933 OPTIONS FOR FTP GATEWAYING
3934 -----------------------------------------------------------------------------
3940 LOC: Config.Ftp.anon_user
3942 If you want the anonymous login password to be more informative
3943 (and enable the use of picky ftp servers), set this to something
3944 reasonable for your domain, like wwwuser@somewhere.net
3946 The reason why this is domainless by default is the
3947 request can be made on the behalf of a user in any domain,
3948 depending on how the cache is used.
3949 Some ftp server also validate the email address is valid
3950 (for example perl.com).
3956 LOC: Config.Ftp.passive
3958 If your firewall does not allow Squid to use passive
3959 connections, turn off this option.
3961 Use of ftp_epsv_all option requires this to be ON.
3967 LOC: Config.Ftp.epsv_all
3969 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
3971 NATs may be able to put the connection on a "fast path" through the
3972 translator, as the EPRT command will never be used and therefore,
3973 translation of the data portion of the segments will never be needed.
3975 When a client only expects to do two-way FTP transfers this may be
3977 If squid finds that it must do a three-way FTP transfer after issuing
3978 an EPSV ALL command, the FTP session will fail.
3980 If you have any doubts about this option do not use it.
3981 Squid will nicely attempt all other connection methods.
3983 Requires ftp_passive to be ON (default) for any effect.
3989 LOC: Config.Ftp.epsv
3991 FTP Protocol extensions permit the use of a special "EPSV" command.
3993 NATs may be able to put the connection on a "fast path" through the
3994 translator using EPSV, as the EPRT command will never be used
3995 and therefore, translation of the data portion of the segments
3996 will never be needed.
3998 Turning this OFF will prevent EPSV being attempted.
3999 WARNING: Doing so will convert Squid back to the old behavior with all
4000 the related problems with external NAT devices/layers.
4002 Requires ftp_passive to be ON (default) for any effect.
4008 LOC: Config.Ftp.eprt
4010 FTP Protocol extensions permit the use of a special "EPRT" command.
4012 This extension provides a protocol neutral alternative to the
4013 IPv4-only PORT command. When supported it enables active FTP data
4014 channels over IPv6 and efficient NAT handling.
4016 Turning this OFF will prevent EPRT being attempted and will skip
4017 straight to using PORT for IPv4 servers.
4019 Some devices are known to not handle this extension correctly and
4020 may result in crashes. Devices which suport EPRT enough to fail
4021 cleanly will result in Squid attempting PORT anyway. This directive
4022 should only be disabled when EPRT results in device failures.
4024 WARNING: Doing so will convert Squid back to the old behavior with all
4025 the related problems with external NAT devices/layers and IPv4-only FTP.
4028 NAME: ftp_sanitycheck
4031 LOC: Config.Ftp.sanitycheck
4033 For security and data integrity reasons Squid by default performs
4034 sanity checks of the addresses of FTP data connections ensure the
4035 data connection is to the requested server. If you need to allow
4036 FTP connections to servers using another IP address for the data
4037 connection turn this off.
4040 NAME: ftp_telnet_protocol
4043 LOC: Config.Ftp.telnet
4045 The FTP protocol is officially defined to use the telnet protocol
4046 as transport channel for the control connection. However, many
4047 implementations are broken and does not respect this aspect of
4050 If you have trouble accessing files with ASCII code 255 in the
4051 path or similar problems involving this ASCII code you can
4052 try setting this directive to off. If that helps, report to the
4053 operator of the FTP server in question that their FTP server
4054 is broken and does not follow the FTP standard.
4058 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4059 -----------------------------------------------------------------------------
4064 DEFAULT: @DEFAULT_DISKD@
4065 LOC: Config.Program.diskd
4067 Specify the location of the diskd executable.
4068 Note this is only useful if you have compiled in
4069 diskd as one of the store io modules.
4072 NAME: unlinkd_program
4075 DEFAULT: @DEFAULT_UNLINKD@
4076 LOC: Config.Program.unlinkd
4078 Specify the location of the executable for file deletion process.
4081 NAME: pinger_program
4083 DEFAULT: @DEFAULT_PINGER@
4084 LOC: Config.pinger.program
4087 Specify the location of the executable for the pinger process.
4093 LOC: Config.pinger.enable
4096 Control whether the pinger is active at run-time.
4097 Enables turning ICMP pinger on and off with a simple
4098 squid -k reconfigure.
4103 OPTIONS FOR URL REWRITING
4104 -----------------------------------------------------------------------------
4107 NAME: url_rewrite_program redirect_program
4109 LOC: Config.Program.redirect
4112 Specify the location of the executable URL rewriter to use.
4113 Since they can perform almost any function there isn't one included.
4115 For each requested URL, the rewriter will receive on line with the format
4117 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
4119 In the future, the rewriter interface will be extended with
4120 key=value pairs ("kvpairs" shown above). Rewriter programs
4121 should be prepared to receive and possibly ignore additional
4122 whitespace-separated tokens on each input line.
4124 And the rewriter may return a rewritten URL. The other components of
4125 the request line does not need to be returned (ignored if they are).
4127 The rewriter can also indicate that a client-side redirect should
4128 be performed to the new URL. This is done by prefixing the returned
4129 URL with "301:" (moved permanently) or 302: (moved temporarily), etc.
4131 By default, a URL rewriter is not used.
4134 NAME: url_rewrite_children redirect_children
4135 TYPE: HelperChildConfig
4136 DEFAULT: 20 startup=0 idle=1 concurrency=0
4137 LOC: Config.redirectChildren
4139 The maximum number of redirector processes to spawn. If you limit
4140 it too few Squid will have to wait for them to process a backlog of
4141 URLs, slowing it down. If you allow too many they will use RAM
4142 and other system resources noticably.
4144 The startup= and idle= options allow some measure of skew in your
4149 Sets a minimum of how many processes are to be spawned when Squid
4150 starts or reconfigures. When set to zero the first request will
4151 cause spawning of the first child process to handle it.
4153 Starting too few will cause an initial slowdown in traffic as Squid
4154 attempts to simultaneously spawn enough processes to cope.
4158 Sets a minimum of how many processes Squid is to try and keep available
4159 at all times. When traffic begins to rise above what the existing
4160 processes can handle this many more will be spawned up to the maximum
4161 configured. A minimum setting of 1 is required.
4165 The number of requests each redirector helper can handle in
4166 parallel. Defaults to 0 which indicates the redirector
4167 is a old-style single threaded redirector.
4169 When this directive is set to a value >= 1 then the protocol
4170 used to communicate with the helper is modified to include
4171 a request ID in front of the request/response. The request
4172 ID from the request must be echoed back with the response
4176 NAME: url_rewrite_host_header redirect_rewrites_host_header
4179 LOC: Config.onoff.redir_rewrites_host
4181 To preserve same-origin security policies in browsers and
4182 prevent Host: header forgery by redirectors Squid rewrites
4183 any Host: header in redirected requests.
4185 If you are running an accelerator this may not be a wanted
4186 effect of a redirector. This directive enables you disable
4187 Host: alteration in reverse-proxy traffic.
4189 WARNING: Entries are cached on the result of the URL rewriting
4190 process, so be careful if you have domain-virtual hosts.
4192 WARNING: Squid and other software verifies the URL and Host
4193 are matching, so be careful not to relay through other proxies
4194 or inspecting firewalls with this disabled.
4197 NAME: url_rewrite_access redirector_access
4200 LOC: Config.accessList.redirector
4202 If defined, this access list specifies which requests are
4203 sent to the redirector processes. By default all requests
4206 This clause supports both fast and slow acl types.
4207 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4210 NAME: url_rewrite_bypass redirector_bypass
4212 LOC: Config.onoff.redirector_bypass
4215 When this is 'on', a request will not go through the
4216 redirector if all redirectors are busy. If this is 'off'
4217 and the redirector queue grows too large, Squid will exit
4218 with a FATAL error and ask you to increase the number of
4219 redirectors. You should only enable this if the redirectors
4220 are not critical to your caching system. If you use
4221 redirectors for access control, and you enable this option,
4222 users may have access to pages they should not
4223 be allowed to request.
4227 OPTIONS FOR TUNING THE CACHE
4228 -----------------------------------------------------------------------------
4231 NAME: cache no_cache
4234 LOC: Config.accessList.noCache
4236 A list of ACL elements which, if matched and denied, cause the request to
4237 not be satisfied from the cache and the reply to not be cached.
4238 In other words, use this to force certain objects to never be cached.
4240 You must use the words 'allow' or 'deny' to indicate whether items
4241 matching the ACL should be allowed or denied into the cache.
4243 Default is to allow all to be cached.
4245 This clause supports both fast and slow acl types.
4246 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4252 LOC: Config.maxStale
4255 This option puts an upper limit on how stale content Squid
4256 will serve from the cache if cache validation fails.
4257 Can be overriden by the refresh_pattern max-stale option.
4260 NAME: refresh_pattern
4261 TYPE: refreshpattern
4265 usage: refresh_pattern [-i] regex min percent max [options]
4267 By default, regular expressions are CASE-SENSITIVE. To make
4268 them case-insensitive, use the -i option.
4270 'Min' is the time (in minutes) an object without an explicit
4271 expiry time should be considered fresh. The recommended
4272 value is 0, any higher values may cause dynamic applications
4273 to be erroneously cached unless the application designer
4274 has taken the appropriate actions.
4276 'Percent' is a percentage of the objects age (time since last
4277 modification age) an object without explicit expiry time
4278 will be considered fresh.
4280 'Max' is an upper limit on how long objects without an explicit
4281 expiry time will be considered fresh.
4283 options: override-expire
4288 ignore-must-revalidate
4295 override-expire enforces min age even if the server
4296 sent an explicit expiry time (e.g., with the
4297 Expires: header or Cache-Control: max-age). Doing this
4298 VIOLATES the HTTP standard. Enabling this feature
4299 could make you liable for problems which it causes.
4301 Note: override-expire does not enforce staleness - it only extends
4302 freshness / min. If the server returns a Expires time which
4303 is longer than your max time, Squid will still consider
4304 the object fresh for that period of time.
4306 override-lastmod enforces min age even on objects
4307 that were modified recently.
4309 reload-into-ims changes client no-cache or ``reload''
4310 to If-Modified-Since requests. Doing this VIOLATES the
4311 HTTP standard. Enabling this feature could make you
4312 liable for problems which it causes.
4314 ignore-reload ignores a client no-cache or ``reload''
4315 header. Doing this VIOLATES the HTTP standard. Enabling
4316 this feature could make you liable for problems which
4319 ignore-no-store ignores any ``Cache-control: no-store''
4320 headers received from a server. Doing this VIOLATES
4321 the HTTP standard. Enabling this feature could make you
4322 liable for problems which it causes.
4324 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
4325 headers received from a server. Doing this VIOLATES
4326 the HTTP standard. Enabling this feature could make you
4327 liable for problems which it causes.
4329 ignore-private ignores any ``Cache-control: private''
4330 headers received from a server. Doing this VIOLATES
4331 the HTTP standard. Enabling this feature could make you
4332 liable for problems which it causes.
4334 ignore-auth caches responses to requests with authorization,
4335 as if the originserver had sent ``Cache-control: public''
4336 in the response header. Doing this VIOLATES the HTTP standard.
4337 Enabling this feature could make you liable for problems which
4340 refresh-ims causes squid to contact the origin server
4341 when a client issues an If-Modified-Since request. This
4342 ensures that the client will receive an updated version
4343 if one is available.
4345 store-stale stores responses even if they don't have explicit
4346 freshness or a validator (i.e., Last-Modified or an ETag)
4347 present, or if they're already stale. By default, Squid will
4348 not cache such responses because they usually can't be
4349 reused. Note that such responses will be stale by default.
4351 max-stale=NN provide a maximum staleness factor. Squid won't
4352 serve objects more stale than this even if it failed to
4353 validate the object. Default: use the max_stale global limit.
4355 Basically a cached object is:
4357 FRESH if expires < now, else STALE
4359 FRESH if lm-factor < percent, else STALE
4363 The refresh_pattern lines are checked in the order listed here.
4364 The first entry which matches is used. If none of the entries
4365 match the default will be used.
4367 Note, you must uncomment all the default lines if you want
4368 to change one. The default setting is only active if none is
4373 # Add any of your own refresh_pattern entries above these.
4374 refresh_pattern ^ftp: 1440 20% 10080
4375 refresh_pattern ^gopher: 1440 0% 1440
4376 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
4377 refresh_pattern . 0 20% 4320
4381 NAME: quick_abort_min
4385 LOC: Config.quickAbort.min
4388 NAME: quick_abort_max
4392 LOC: Config.quickAbort.max
4395 NAME: quick_abort_pct
4399 LOC: Config.quickAbort.pct
4401 The cache by default continues downloading aborted requests
4402 which are almost completed (less than 16 KB remaining). This
4403 may be undesirable on slow (e.g. SLIP) links and/or very busy
4404 caches. Impatient users may tie up file descriptors and
4405 bandwidth by repeatedly requesting and immediately aborting
4408 When the user aborts a request, Squid will check the
4409 quick_abort values to the amount of data transfered until
4412 If the transfer has less than 'quick_abort_min' KB remaining,
4413 it will finish the retrieval.
4415 If the transfer has more than 'quick_abort_max' KB remaining,
4416 it will abort the retrieval.
4418 If more than 'quick_abort_pct' of the transfer has completed,
4419 it will finish the retrieval.
4421 If you do not want any retrieval to continue after the client
4422 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
4425 If you want retrievals to always continue if they are being
4426 cached set 'quick_abort_min' to '-1 KB'.
4429 NAME: read_ahead_gap
4430 COMMENT: buffer-size
4432 LOC: Config.readAheadGap
4435 The amount of data the cache will buffer ahead of what has been
4436 sent to the client when retrieving an object from another server.
4440 IFDEF: USE_HTTP_VIOLATIONS
4443 LOC: Config.negativeTtl
4446 Set the Default Time-to-Live (TTL) for failed requests.
4447 Certain types of failures (such as "connection refused" and
4448 "404 Not Found") are able to be negatively-cached for a short time.
4449 Modern web servers should provide Expires: header, however if they
4450 do not this can provide a minimum TTL.
4451 The default is not to cache errors with unknown expiry details.
4453 Note that this is different from negative caching of DNS lookups.
4455 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4456 this feature could make you liable for problems which it
4460 NAME: positive_dns_ttl
4463 LOC: Config.positiveDnsTtl
4466 Upper limit on how long Squid will cache positive DNS responses.
4467 Default is 6 hours (360 minutes). This directive must be set
4468 larger than negative_dns_ttl.
4471 NAME: negative_dns_ttl
4474 LOC: Config.negativeDnsTtl
4477 Time-to-Live (TTL) for negative caching of failed DNS lookups.
4478 This also sets the lower cache limit on positive lookups.
4479 Minimum value is 1 second, and it is not recommendable to go
4480 much below 10 seconds.
4483 NAME: range_offset_limit
4484 COMMENT: size [acl acl...]
4486 LOC: Config.rangeOffsetLimit
4489 usage: (size) [units] [[!]aclname]
4491 Sets an upper limit on how far (number of bytes) into the file
4492 a Range request may be to cause Squid to prefetch the whole file.
4493 If beyond this limit, Squid forwards the Range request as it is and
4494 the result is NOT cached.
4496 This is to stop a far ahead range request (lets say start at 17MB)
4497 from making Squid fetch the whole object up to that point before
4498 sending anything to the client.
4500 Multiple range_offset_limit lines may be specified, and they will
4501 be searched from top to bottom on each request until a match is found.
4502 The first match found will be used. If no line matches a request, the
4503 default limit of 0 bytes will be used.
4505 'size' is the limit specified as a number of units.
4507 'units' specifies whether to use bytes, KB, MB, etc.
4508 If no units are specified bytes are assumed.
4510 A size of 0 causes Squid to never fetch more than the
4511 client requested. (default)
4513 A size of 'none' causes Squid to always fetch the object from the
4514 beginning so it may cache the result. (2.0 style)
4516 'aclname' is the name of a defined ACL.
4518 NP: Using 'none' as the byte value here will override any quick_abort settings
4519 that may otherwise apply to the range request. The range request will
4520 be fully fetched from start to finish regardless of the client
4521 actions. This affects bandwidth usage.
4524 NAME: minimum_expiry_time
4527 LOC: Config.minimum_expiry_time
4530 The minimum caching time according to (Expires - Date)
4531 Headers Squid honors if the object can't be revalidated
4532 defaults to 60 seconds. In reverse proxy environments it
4533 might be desirable to honor shorter object lifetimes. It
4534 is most likely better to make your server return a
4535 meaningful Last-Modified header however. In ESI environments
4536 where page fragments often have short lifetimes, this will
4537 often be best set to 0.
4540 NAME: store_avg_object_size
4544 LOC: Config.Store.avgObjectSize
4546 Average object size, used to estimate number of objects your
4547 cache can hold. The default is 13 KB.
4550 NAME: store_objects_per_bucket
4553 LOC: Config.Store.objectsPerBucket
4555 Target number of objects per bucket in the store hash table.
4556 Lowering this value increases the total number of buckets and
4557 also the storage maintenance rate. The default is 20.
4562 -----------------------------------------------------------------------------
4565 NAME: request_header_max_size
4569 LOC: Config.maxRequestHeaderSize
4571 This specifies the maximum size for HTTP headers in a request.
4572 Request headers are usually relatively small (about 512 bytes).
4573 Placing a limit on the request header size will catch certain
4574 bugs (for example with persistent connections) and possibly
4575 buffer-overflow or denial-of-service attacks.
4578 NAME: reply_header_max_size
4582 LOC: Config.maxReplyHeaderSize
4584 This specifies the maximum size for HTTP headers in a reply.
4585 Reply headers are usually relatively small (about 512 bytes).
4586 Placing a limit on the reply header size will catch certain
4587 bugs (for example with persistent connections) and possibly
4588 buffer-overflow or denial-of-service attacks.
4591 NAME: request_body_max_size
4595 LOC: Config.maxRequestBodySize
4597 This specifies the maximum size for an HTTP request body.
4598 In other words, the maximum size of a PUT/POST request.
4599 A user who attempts to send a request with a body larger
4600 than this limit receives an "Invalid Request" error message.
4601 If you set this parameter to a zero (the default), there will
4602 be no limit imposed.
4605 NAME: client_request_buffer_max_size
4609 LOC: Config.maxRequestBufferSize
4611 This specifies the maximum buffer size of a client request.
4612 It prevents squid eating too much memory when somebody uploads
4616 NAME: chunked_request_body_max_size
4620 LOC: Config.maxChunkedRequestBodySize
4622 A broken or confused HTTP/1.1 client may send a chunked HTTP
4623 request to Squid. Squid does not have full support for that
4624 feature yet. To cope with such requests, Squid buffers the
4625 entire request and then dechunks request body to create a
4626 plain HTTP/1.0 request with a known content length. The plain
4627 request is then used by the rest of Squid code as usual.
4629 The option value specifies the maximum size of the buffer used
4630 to hold the request before the conversion. If the chunked
4631 request size exceeds the specified limit, the conversion
4632 fails, and the client receives an "unsupported request" error,
4633 as if dechunking was disabled.
4635 Dechunking is enabled by default. To disable conversion of
4636 chunked requests, set the maximum to zero.
4638 Request dechunking feature and this option in particular are a
4639 temporary hack. When chunking requests and responses are fully
4640 supported, there will be no need to buffer a chunked request.
4644 IFDEF: USE_HTTP_VIOLATIONS
4647 LOC: Config.accessList.brokenPosts
4649 A list of ACL elements which, if matched, causes Squid to send
4650 an extra CRLF pair after the body of a PUT/POST request.
4652 Some HTTP servers has broken implementations of PUT/POST,
4653 and rely on an extra CRLF pair sent by some WWW clients.
4655 Quote from RFC2616 section 4.1 on this matter:
4657 Note: certain buggy HTTP/1.0 client implementations generate an
4658 extra CRLF's after a POST request. To restate what is explicitly
4659 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
4660 a request with an extra CRLF.
4662 This clause only supports fast acl types.
4663 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4666 acl buggy_server url_regex ^http://....
4667 broken_posts allow buggy_server
4670 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
4673 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
4675 LOC: Adaptation::Config::use_indirect_client
4677 Controls whether the indirect client IP address (instead of the direct
4678 client IP address) is passed to adaptation services.
4680 See also: follow_x_forwarded_for adaptation_send_client_ip
4684 IFDEF: USE_HTTP_VIOLATIONS
4688 LOC: Config.onoff.via
4690 If set (default), Squid will include a Via header in requests and
4691 replies as required by RFC2616.
4697 LOC: Config.onoff.ie_refresh
4700 Microsoft Internet Explorer up until version 5.5 Service
4701 Pack 1 has an issue with transparent proxies, wherein it
4702 is impossible to force a refresh. Turning this on provides
4703 a partial fix to the problem, by causing all IMS-REFRESH
4704 requests from older IE versions to check the origin server
4705 for fresh content. This reduces hit ratio by some amount
4706 (~10% in my experience), but allows users to actually get
4707 fresh content when they want it. Note because Squid
4708 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
4709 of 5.5 is unchanged from old versions of Squid (i.e. a
4710 forced refresh is impossible). Newer versions of IE will,
4711 hopefully, continue to have the new behavior and will be
4712 handled based on that assumption. This option defaults to
4713 the old Squid behavior, which is better for hit ratios but
4714 worse for clients using IE, if they need to be able to
4715 force fresh content.
4718 NAME: vary_ignore_expire
4721 LOC: Config.onoff.vary_ignore_expire
4724 Many HTTP servers supporting Vary gives such objects
4725 immediate expiry time with no cache-control header
4726 when requested by a HTTP/1.0 client. This option
4727 enables Squid to ignore such expiry times until
4728 HTTP/1.1 is fully implemented.
4730 WARNING: If turned on this may eventually cause some
4731 varying objects not intended for caching to get cached.
4734 NAME: request_entities
4736 LOC: Config.onoff.request_entities
4739 Squid defaults to deny GET and HEAD requests with request entities,
4740 as the meaning of such requests are undefined in the HTTP standard
4741 even if not explicitly forbidden.
4743 Set this directive to on if you have clients which insists
4744 on sending request entities in GET or HEAD requests. But be warned
4745 that there is server software (both proxies and web servers) which
4746 can fail to properly process this kind of request which may make you
4747 vulnerable to cache pollution attacks if enabled.
4750 NAME: request_header_access
4751 IFDEF: USE_HTTP_VIOLATIONS
4752 TYPE: http_header_access
4753 LOC: Config.request_header_access
4756 Usage: request_header_access header_name allow|deny [!]aclname ...
4758 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4759 this feature could make you liable for problems which it
4762 This option replaces the old 'anonymize_headers' and the
4763 older 'http_anonymizer' option with something that is much
4764 more configurable. A list of ACLs for each header name allows
4765 removal of specific header fields under specific conditions.
4767 This option only applies to outgoing HTTP request headers (i.e.,
4768 headers sent by Squid to the next HTTP hop such as a cache peer
4769 or an origin server). The option has no effect during cache hit
4770 detection. The equivalent adaptation vectoring point in ICAP
4771 terminology is post-cache REQMOD.
4773 The option is applied to individual outgoing request header
4774 fields. For each request header field F, Squid uses the first
4775 qualifying sets of request_header_access rules:
4777 1. Rules with header_name equal to F's name.
4778 2. Rules with header_name 'Other', provided F's name is not
4779 on the hard-coded list of commonly used HTTP header names.
4780 3. Rules with header_name 'All'.
4782 Within that qualifying rule set, rule ACLs are checked as usual.
4783 If ACLs of an "allow" rule match, the header field is allowed to
4784 go through as is. If ACLs of a "deny" rule match, the header is
4785 removed and request_header_replace is then checked to identify
4786 if the removed header has a replacement. If no rules within the
4787 set have matching ACLs, the header field is left as is.
4789 For example, to achieve the same behavior as the old
4790 'http_anonymizer standard' option, you should use:
4792 request_header_access From deny all
4793 request_header_access Referer deny all
4794 request_header_access Server deny all
4795 request_header_access User-Agent deny all
4796 request_header_access WWW-Authenticate deny all
4797 request_header_access Link deny all
4799 Or, to reproduce the old 'http_anonymizer paranoid' feature
4802 request_header_access Allow allow all
4803 request_header_access Authorization allow all
4804 request_header_access WWW-Authenticate allow all
4805 request_header_access Proxy-Authorization allow all
4806 request_header_access Proxy-Authenticate allow all
4807 request_header_access Cache-Control allow all
4808 request_header_access Content-Encoding allow all
4809 request_header_access Content-Length allow all
4810 request_header_access Content-Type allow all
4811 request_header_access Date allow all
4812 request_header_access Expires allow all
4813 request_header_access Host allow all
4814 request_header_access If-Modified-Since allow all
4815 request_header_access Last-Modified allow all
4816 request_header_access Location allow all
4817 request_header_access Pragma allow all
4818 request_header_access Accept allow all
4819 request_header_access Accept-Charset allow all
4820 request_header_access Accept-Encoding allow all
4821 request_header_access Accept-Language allow all
4822 request_header_access Content-Language allow all
4823 request_header_access Mime-Version allow all
4824 request_header_access Retry-After allow all
4825 request_header_access Title allow all
4826 request_header_access Connection allow all
4827 request_header_access All deny all
4829 although many of those are HTTP reply headers, and so should be
4830 controlled with the reply_header_access directive.
4832 By default, all headers are allowed (no anonymizing is
4836 NAME: reply_header_access
4837 IFDEF: USE_HTTP_VIOLATIONS
4838 TYPE: http_header_access
4839 LOC: Config.reply_header_access
4842 Usage: reply_header_access header_name allow|deny [!]aclname ...
4844 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4845 this feature could make you liable for problems which it
4848 This option only applies to reply headers, i.e., from the
4849 server to the client.
4851 This is the same as request_header_access, but in the other
4852 direction. Please see request_header_access for detailed
4855 For example, to achieve the same behavior as the old
4856 'http_anonymizer standard' option, you should use:
4858 reply_header_access From deny all
4859 reply_header_access Referer deny all
4860 reply_header_access Server deny all
4861 reply_header_access User-Agent deny all
4862 reply_header_access WWW-Authenticate deny all
4863 reply_header_access Link deny all
4865 Or, to reproduce the old 'http_anonymizer paranoid' feature
4868 reply_header_access Allow allow all
4869 reply_header_access Authorization allow all
4870 reply_header_access WWW-Authenticate allow all
4871 reply_header_access Proxy-Authorization allow all
4872 reply_header_access Proxy-Authenticate allow all
4873 reply_header_access Cache-Control allow all
4874 reply_header_access Content-Encoding allow all
4875 reply_header_access Content-Length allow all
4876 reply_header_access Content-Type allow all
4877 reply_header_access Date allow all
4878 reply_header_access Expires allow all
4879 reply_header_access Host allow all
4880 reply_header_access If-Modified-Since allow all
4881 reply_header_access Last-Modified allow all
4882 reply_header_access Location allow all
4883 reply_header_access Pragma allow all
4884 reply_header_access Accept allow all
4885 reply_header_access Accept-Charset allow all
4886 reply_header_access Accept-Encoding allow all
4887 reply_header_access Accept-Language allow all
4888 reply_header_access Content-Language allow all
4889 reply_header_access Mime-Version allow all
4890 reply_header_access Retry-After allow all
4891 reply_header_access Title allow all
4892 reply_header_access Connection allow all
4893 reply_header_access All deny all
4895 although the HTTP request headers won't be usefully controlled
4896 by this directive -- see request_header_access for details.
4898 By default, all headers are allowed (no anonymizing is
4902 NAME: request_header_replace header_replace
4903 IFDEF: USE_HTTP_VIOLATIONS
4904 TYPE: http_header_replace
4905 LOC: Config.request_header_access
4908 Usage: request_header_replace header_name message
4909 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
4911 This option allows you to change the contents of headers
4912 denied with request_header_access above, by replacing them
4913 with some fixed string. This replaces the old fake_user_agent
4916 This only applies to request headers, not reply headers.
4918 By default, headers are removed if denied.
4921 NAME: reply_header_replace
4922 IFDEF: USE_HTTP_VIOLATIONS
4923 TYPE: http_header_replace
4924 LOC: Config.reply_header_access
4927 Usage: reply_header_replace header_name message
4928 Example: reply_header_replace Server Foo/1.0
4930 This option allows you to change the contents of headers
4931 denied with reply_header_access above, by replacing them
4932 with some fixed string.
4934 This only applies to reply headers, not request headers.
4936 By default, headers are removed if denied.
4939 NAME: request_header_add
4940 TYPE: HeaderWithAclList
4941 LOC: Config.request_header_add
4944 Usage: request_header_add field-name field-value acl1 [acl2] ...
4945 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
4947 This option adds header fields to outgoing HTTP requests (i.e.,
4948 request headers sent by Squid to the next HTTP hop such as a
4949 cache peer or an origin server). The option has no effect during
4950 cache hit detection. The equivalent adaptation vectoring point
4951 in ICAP terminology is post-cache REQMOD.
4953 Field-name is a token specifying an HTTP header name. If a
4954 standard HTTP header name is used, Squid does not check whether
4955 the new header conflicts with any existing headers or violates
4956 HTTP rules. If the request to be modified already contains a
4957 field with the same name, the old field is preserved but the
4958 header field values are not merged.
4960 Field-value is either a token or a quoted string. If quoted
4961 string format is used, then the surrounding quotes are removed
4962 while escape sequences and %macros are processed.
4964 In theory, all of the logformat codes can be used as %macros.
4965 However, unlike logging (which happens at the very end of
4966 transaction lifetime), the transaction may not yet have enough
4967 information to expand a macro when the new header value is needed.
4968 And some information may already be available to Squid but not yet
4969 committed where the macro expansion code can access it (report
4970 such instances!). The macro will be expanded into a single dash
4971 ('-') in such cases. Not all macros have been tested.
4973 One or more Squid ACLs may be specified to restrict header
4974 injection to matching requests. As always in squid.conf, all
4975 ACLs in an option ACL list must be satisfied for the insertion
4976 to happen. The request_header_add option supports fast ACLs
4985 This option used to log custom information about the master
4986 transaction. For example, an admin may configure Squid to log
4987 which "user group" the transaction belongs to, where "user group"
4988 will be determined based on a set of ACLs and not [just]
4989 authentication information.
4990 Values of key/value pairs can be logged using %{key}note macros:
4992 note key value acl ...
4993 logformat myFormat ... %{key}note ...
4996 NAME: relaxed_header_parser
4997 COMMENT: on|off|warn
4999 LOC: Config.onoff.relaxed_header_parser
5002 In the default "on" setting Squid accepts certain forms
5003 of non-compliant HTTP messages where it is unambiguous
5004 what the sending application intended even if the message
5005 is not correctly formatted. The messages is then normalized
5006 to the correct form when forwarded by Squid.
5008 If set to "warn" then a warning will be emitted in cache.log
5009 each time such HTTP error is encountered.
5011 If set to "off" then such HTTP errors will cause the request
5012 or response to be rejected.
5017 -----------------------------------------------------------------------------
5020 NAME: forward_timeout
5023 LOC: Config.Timeout.forward
5026 This parameter specifies how long Squid should at most attempt in
5027 finding a forwarding path for the request before giving up.
5030 NAME: connect_timeout
5033 LOC: Config.Timeout.connect
5036 This parameter specifies how long to wait for the TCP connect to
5037 the requested server or peer to complete before Squid should
5038 attempt to find another path where to forward the request.
5041 NAME: peer_connect_timeout
5044 LOC: Config.Timeout.peer_connect
5047 This parameter specifies how long to wait for a pending TCP
5048 connection to a peer cache. The default is 30 seconds. You
5049 may also set different timeout values for individual neighbors
5050 with the 'connect-timeout' option on a 'cache_peer' line.
5056 LOC: Config.Timeout.read
5059 The read_timeout is applied on server-side connections. After
5060 each successful read(), the timeout will be extended by this
5061 amount. If no data is read again after this amount of time,
5062 the request is aborted and logged with ERR_READ_TIMEOUT. The
5063 default is 15 minutes.
5069 LOC: Config.Timeout.write
5072 This timeout is tracked for all connections that have data
5073 available for writing and are waiting for the socket to become
5074 ready. After each successful write, the timeout is extended by
5075 the configured amount. If Squid has data to write but the
5076 connection is not ready for the configured duration, the
5077 transaction associated with the connection is terminated. The
5078 default is 15 minutes.
5081 NAME: request_timeout
5083 LOC: Config.Timeout.request
5086 How long to wait for complete HTTP request headers after initial
5087 connection establishment.
5090 NAME: client_idle_pconn_timeout persistent_request_timeout
5092 LOC: Config.Timeout.clientIdlePconn
5095 How long to wait for the next HTTP request on a persistent
5096 client connection after the previous request completes.
5099 NAME: client_lifetime
5102 LOC: Config.Timeout.lifetime
5105 The maximum amount of time a client (browser) is allowed to
5106 remain connected to the cache process. This protects the Cache
5107 from having a lot of sockets (and hence file descriptors) tied up
5108 in a CLOSE_WAIT state from remote clients that go away without
5109 properly shutting down (either because of a network failure or
5110 because of a poor client implementation). The default is one
5113 NOTE: The default value is intended to be much larger than any
5114 client would ever need to be connected to your cache. You
5115 should probably change client_lifetime only as a last resort.
5116 If you seem to have many client connections tying up
5117 filedescriptors, we recommend first tuning the read_timeout,
5118 request_timeout, persistent_request_timeout and quick_abort values.
5121 NAME: half_closed_clients
5123 LOC: Config.onoff.half_closed_clients
5126 Some clients may shutdown the sending side of their TCP
5127 connections, while leaving their receiving sides open. Sometimes,
5128 Squid can not tell the difference between a half-closed and a
5129 fully-closed TCP connection.
5131 By default, Squid will immediately close client connections when
5132 read(2) returns "no more data to read."
5134 Change this option to 'on' and Squid will keep open connections
5135 until a read(2) or write(2) on the socket returns an error.
5136 This may show some benefits for reverse proxies. But if not
5137 it is recommended to leave OFF.
5140 NAME: server_idle_pconn_timeout pconn_timeout
5142 LOC: Config.Timeout.serverIdlePconn
5145 Timeout for idle persistent connections to servers and other
5152 LOC: Ident::TheConfig.timeout
5155 Maximum time to wait for IDENT lookups to complete.
5157 If this is too high, and you enabled IDENT lookups from untrusted
5158 users, you might be susceptible to denial-of-service by having
5159 many ident requests going at once.
5162 NAME: shutdown_lifetime
5165 LOC: Config.shutdownLifetime
5168 When SIGTERM or SIGHUP is received, the cache is put into
5169 "shutdown pending" mode until all active sockets are closed.
5170 This value is the lifetime to set for all open descriptors
5171 during shutdown mode. Any active clients after this many
5172 seconds will receive a 'timeout' message.
5176 ADMINISTRATIVE PARAMETERS
5177 -----------------------------------------------------------------------------
5183 LOC: Config.adminEmail
5185 Email-address of local cache manager who will receive
5186 mail if the cache dies. The default is "webmaster."
5192 LOC: Config.EmailFrom
5194 From: email-address for mail sent when the cache dies.
5195 The default is to use 'appname@unique_hostname'.
5196 Default appname value is "squid", can be changed into
5197 src/globals.h before building squid.
5203 LOC: Config.EmailProgram
5205 Email program used to send mail if the cache dies.
5206 The default is "mail". The specified program must comply
5207 with the standard Unix mail syntax:
5208 mail-program recipient < mailfile
5210 Optional command line options can be specified.
5213 NAME: cache_effective_user
5215 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
5216 LOC: Config.effectiveUser
5218 If you start Squid as root, it will change its effective/real
5219 UID/GID to the user specified below. The default is to change
5220 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
5221 see also; cache_effective_group
5224 NAME: cache_effective_group
5227 LOC: Config.effectiveGroup
5229 Squid sets the GID to the effective user's default group ID
5230 (taken from the password file) and supplementary group list
5231 from the groups membership.
5233 If you want Squid to run with a specific GID regardless of
5234 the group memberships of the effective user then set this
5235 to the group (or GID) you want Squid to run as. When set
5236 all other group privileges of the effective user are ignored
5237 and only this GID is effective. If Squid is not started as
5238 root the user starting Squid MUST be member of the specified
5241 This option is not recommended by the Squid Team.
5242 Our preference is for administrators to configure a secure
5243 user account for squid with UID/GID matching system policies.
5246 NAME: httpd_suppress_version_string
5250 LOC: Config.onoff.httpd_suppress_version_string
5252 Suppress Squid version string info in HTTP headers and HTML error pages.
5255 NAME: visible_hostname
5257 LOC: Config.visibleHostname
5260 If you want to present a special hostname in error messages, etc,
5261 define this. Otherwise, the return value of gethostname()
5262 will be used. If you have multiple caches in a cluster and
5263 get errors about IP-forwarding you must set them to have individual
5264 names with this setting.
5267 NAME: unique_hostname
5269 LOC: Config.uniqueHostname
5272 If you want to have multiple machines with the same
5273 'visible_hostname' you must give each machine a different
5274 'unique_hostname' so forwarding loops can be detected.
5277 NAME: hostname_aliases
5279 LOC: Config.hostnameAliases
5282 A list of other DNS names your cache has.
5290 Minimum umask which should be enforced while the proxy
5291 is running, in addition to the umask set at startup.
5293 For a traditional octal representation of umasks, start
5298 OPTIONS FOR THE CACHE REGISTRATION SERVICE
5299 -----------------------------------------------------------------------------
5301 This section contains parameters for the (optional) cache
5302 announcement service. This service is provided to help
5303 cache administrators locate one another in order to join or
5304 create cache hierarchies.
5306 An 'announcement' message is sent (via UDP) to the registration
5307 service by Squid. By default, the announcement message is NOT
5308 SENT unless you enable it with 'announce_period' below.
5310 The announcement message includes your hostname, plus the
5311 following information from this configuration file:
5317 All current information is processed regularly and made
5318 available on the Web at http://www.ircache.net/Cache/Tracker/.
5321 NAME: announce_period
5323 LOC: Config.Announce.period
5326 This is how frequently to send cache announcements. The
5327 default is `0' which disables sending the announcement
5330 To enable announcing your cache, just set an announce period.
5333 announce_period 1 day
5338 DEFAULT: tracker.ircache.net
5339 LOC: Config.Announce.host
5345 LOC: Config.Announce.file
5351 LOC: Config.Announce.port
5353 announce_host and announce_port set the hostname and port
5354 number where the registration message will be sent.
5356 Hostname will default to 'tracker.ircache.net' and port will
5357 default default to 3131. If the 'filename' argument is given,
5358 the contents of that file will be included in the announce
5363 HTTPD-ACCELERATOR OPTIONS
5364 -----------------------------------------------------------------------------
5367 NAME: httpd_accel_surrogate_id
5370 LOC: Config.Accel.surrogate_id
5372 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
5373 need an identification token to allow control targeting. Because
5374 a farm of surrogates may all perform the same tasks, they may share
5375 an identification token.
5377 The default ID is the visible_hostname
5380 NAME: http_accel_surrogate_remote
5384 LOC: Config.onoff.surrogate_is_remote
5386 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
5387 Set this to on to have squid behave as a remote surrogate.
5391 IFDEF: USE_SQUID_ESI
5392 COMMENT: libxml2|expat|custom
5394 LOC: ESIParser::Type
5397 ESI markup is not strictly XML compatible. The custom ESI parser
5398 will give higher performance, but cannot handle non ASCII character
5403 DELAY POOL PARAMETERS
5404 -----------------------------------------------------------------------------
5408 TYPE: delay_pool_count
5410 IFDEF: USE_DELAY_POOLS
5413 This represents the number of delay pools to be used. For example,
5414 if you have one class 2 delay pool and one class 3 delays pool, you
5415 have a total of 2 delay pools.
5419 TYPE: delay_pool_class
5421 IFDEF: USE_DELAY_POOLS
5424 This defines the class of each delay pool. There must be exactly one
5425 delay_class line for each delay pool. For example, to define two
5426 delay pools, one of class 2 and one of class 3, the settings above
5430 delay_pools 4 # 4 delay pools
5431 delay_class 1 2 # pool 1 is a class 2 pool
5432 delay_class 2 3 # pool 2 is a class 3 pool
5433 delay_class 3 4 # pool 3 is a class 4 pool
5434 delay_class 4 5 # pool 4 is a class 5 pool
5436 The delay pool classes are:
5438 class 1 Everything is limited by a single aggregate
5441 class 2 Everything is limited by a single aggregate
5442 bucket as well as an "individual" bucket chosen
5443 from bits 25 through 32 of the IPv4 address.
5445 class 3 Everything is limited by a single aggregate
5446 bucket as well as a "network" bucket chosen
5447 from bits 17 through 24 of the IP address and a
5448 "individual" bucket chosen from bits 17 through
5449 32 of the IPv4 address.
5451 class 4 Everything in a class 3 delay pool, with an
5452 additional limit on a per user basis. This
5453 only takes effect if the username is established
5454 in advance - by forcing authentication in your
5457 class 5 Requests are grouped according their tag (see
5458 external_acl's tag= reply).
5461 Each pool also requires a delay_parameters directive to configure the pool size
5462 and speed limits used whenever the pool is applied to a request. Along with
5463 a set of delay_access directives to determine when it is used.
5465 NOTE: If an IP address is a.b.c.d
5466 -> bits 25 through 32 are "d"
5467 -> bits 17 through 24 are "c"
5468 -> bits 17 through 32 are "c * 256 + d"
5470 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
5471 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
5475 TYPE: delay_pool_access
5477 IFDEF: USE_DELAY_POOLS
5480 This is used to determine which delay pool a request falls into.
5482 delay_access is sorted per pool and the matching starts with pool 1,
5483 then pool 2, ..., and finally pool N. The first delay pool where the
5484 request is allowed is selected for the request. If it does not allow
5485 the request to any pool then the request is not delayed (default).
5487 For example, if you want some_big_clients in delay
5488 pool 1 and lotsa_little_clients in delay pool 2:
5491 delay_access 1 allow some_big_clients
5492 delay_access 1 deny all
5493 delay_access 2 allow lotsa_little_clients
5494 delay_access 2 deny all
5495 delay_access 3 allow authenticated_clients
5498 NAME: delay_parameters
5499 TYPE: delay_pool_rates
5501 IFDEF: USE_DELAY_POOLS
5504 This defines the parameters for a delay pool. Each delay pool has
5505 a number of "buckets" associated with it, as explained in the
5506 description of delay_class.
5508 For a class 1 delay pool, the syntax is:
5510 delay_parameters pool aggregate
5512 For a class 2 delay pool:
5514 delay_parameters pool aggregate individual
5516 For a class 3 delay pool:
5518 delay_parameters pool aggregate network individual
5520 For a class 4 delay pool:
5522 delay_parameters pool aggregate network individual user
5524 For a class 5 delay pool:
5526 delay_parameters pool tagrate
5528 The option variables are:
5530 pool a pool number - ie, a number between 1 and the
5531 number specified in delay_pools as used in
5534 aggregate the speed limit parameters for the aggregate bucket
5537 individual the speed limit parameters for the individual
5538 buckets (class 2, 3).
5540 network the speed limit parameters for the network buckets
5543 user the speed limit parameters for the user buckets
5546 tagrate the speed limit parameters for the tag buckets
5549 A pair of delay parameters is written restore/maximum, where restore is
5550 the number of bytes (not bits - modem and network speeds are usually
5551 quoted in bits) per second placed into the bucket, and maximum is the
5552 maximum number of bytes which can be in the bucket at any time.
5554 There must be one delay_parameters line for each delay pool.
5557 For example, if delay pool number 1 is a class 2 delay pool as in the
5558 above example, and is being used to strictly limit each host to 64Kbit/sec
5559 (plus overheads), with no overall limit, the line is:
5561 delay_parameters 1 -1/-1 8000/8000
5563 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
5565 Note that the figure -1 is used to represent "unlimited".
5568 And, if delay pool number 2 is a class 3 delay pool as in the above
5569 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
5570 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
5571 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
5572 to permit a decent web page to be downloaded at a decent speed
5573 (if the network is not being limited due to overuse) but slow down
5574 large downloads more significantly:
5576 delay_parameters 2 32000/32000 8000/8000 600/8000
5578 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
5579 8 x 8000 KByte/sec -> 64Kbit/sec.
5580 8 x 600 Byte/sec -> 4800bit/sec.
5583 Finally, for a class 4 delay pool as in the example - each user will
5584 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
5586 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
5589 NAME: delay_initial_bucket_level
5590 COMMENT: (percent, 0-100)
5593 IFDEF: USE_DELAY_POOLS
5594 LOC: Config.Delay.initial
5596 The initial bucket percentage is used to determine how much is put
5597 in each bucket when squid starts, is reconfigured, or first notices
5598 a host accessing it (in class 2 and class 3, individual hosts and
5599 networks only have buckets associated with them once they have been
5604 CLIENT DELAY POOL PARAMETERS
5605 -----------------------------------------------------------------------------
5608 NAME: client_delay_pools
5609 TYPE: client_delay_pool_count
5611 IFDEF: USE_DELAY_POOLS
5612 LOC: Config.ClientDelay
5614 This option specifies the number of client delay pools used. It must
5615 preceed other client_delay_* options.
5618 client_delay_pools 2
5621 NAME: client_delay_initial_bucket_level
5622 COMMENT: (percent, 0-no_limit)
5625 IFDEF: USE_DELAY_POOLS
5626 LOC: Config.ClientDelay.initial
5628 This option determines the initial bucket size as a percentage of
5629 max_bucket_size from client_delay_parameters. Buckets are created
5630 at the time of the "first" connection from the matching IP. Idle
5631 buckets are periodically deleted up.
5633 You can specify more than 100 percent but note that such "oversized"
5634 buckets are not refilled until their size goes down to max_bucket_size
5635 from client_delay_parameters.
5638 client_delay_initial_bucket_level 50
5641 NAME: client_delay_parameters
5642 TYPE: client_delay_pool_rates
5644 IFDEF: USE_DELAY_POOLS
5645 LOC: Config.ClientDelay
5648 This option configures client-side bandwidth limits using the
5651 client_delay_parameters pool speed_limit max_bucket_size
5653 pool is an integer ID used for client_delay_access matching.
5655 speed_limit is bytes added to the bucket per second.
5657 max_bucket_size is the maximum size of a bucket, enforced after any
5658 speed_limit additions.
5660 Please see the delay_parameters option for more information and
5664 client_delay_parameters 1 1024 2048
5665 client_delay_parameters 2 51200 16384
5668 NAME: client_delay_access
5669 TYPE: client_delay_pool_access
5671 IFDEF: USE_DELAY_POOLS
5672 LOC: Config.ClientDelay
5675 This option determines the client-side delay pool for the
5678 client_delay_access pool_ID allow|deny acl_name
5680 All client_delay_access options are checked in their pool ID
5681 order, starting with pool 1. The first checked pool with allowed
5682 request is selected for the request. If no ACL matches or there
5683 are no client_delay_access options, the request bandwidth is not
5686 The ACL-selected pool is then used to find the
5687 client_delay_parameters for the request. Client-side pools are
5688 not used to aggregate clients. Clients are always aggregated
5689 based on their source IP addresses (one bucket per source IP).
5691 Please see delay_access for more examples.
5694 client_delay_access 1 allow low_rate_network
5695 client_delay_access 2 allow vips_network
5699 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
5700 -----------------------------------------------------------------------------
5705 LOC: Config.Wccp.router
5709 Use this option to define your WCCP ``home'' router for
5712 wccp_router supports a single WCCP(v1) router
5714 wccp2_router supports multiple WCCPv2 routers
5716 only one of the two may be used at the same time and defines
5717 which version of WCCP to use.
5721 TYPE: IpAddress_list
5722 LOC: Config.Wccp2.router
5726 Use this option to define your WCCP ``home'' router for
5729 wccp_router supports a single WCCP(v1) router
5731 wccp2_router supports multiple WCCPv2 routers
5733 only one of the two may be used at the same time and defines
5734 which version of WCCP to use.
5739 LOC: Config.Wccp.version
5743 This directive is only relevant if you need to set up WCCP(v1)
5744 to some very old and end-of-life Cisco routers. In all other
5745 setups it must be left unset or at the default setting.
5746 It defines an internal version in the WCCP(v1) protocol,
5747 with version 4 being the officially documented protocol.
5749 According to some users, Cisco IOS 11.2 and earlier only
5750 support WCCP version 3. If you're using that or an earlier
5751 version of IOS, you may need to change this value to 3, otherwise
5752 do not specify this parameter.
5755 NAME: wccp2_rebuild_wait
5757 LOC: Config.Wccp2.rebuildwait
5761 If this is enabled Squid will wait for the cache dir rebuild to finish
5762 before sending the first wccp2 HereIAm packet
5765 NAME: wccp2_forwarding_method
5767 LOC: Config.Wccp2.forwarding_method
5771 WCCP2 allows the setting of forwarding methods between the
5772 router/switch and the cache. Valid values are as follows:
5774 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5775 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5777 Currently (as of IOS 12.4) cisco routers only support GRE.
5778 Cisco switches only support the L2 redirect assignment method.
5781 NAME: wccp2_return_method
5783 LOC: Config.Wccp2.return_method
5787 WCCP2 allows the setting of return methods between the
5788 router/switch and the cache for packets that the cache
5789 decides not to handle. Valid values are as follows:
5791 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5792 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5794 Currently (as of IOS 12.4) cisco routers only support GRE.
5795 Cisco switches only support the L2 redirect assignment.
5797 If the "ip wccp redirect exclude in" command has been
5798 enabled on the cache interface, then it is still safe for
5799 the proxy server to use a l2 redirect method even if this
5800 option is set to GRE.
5803 NAME: wccp2_assignment_method
5805 LOC: Config.Wccp2.assignment_method
5809 WCCP2 allows the setting of methods to assign the WCCP hash
5810 Valid values are as follows:
5812 hash - Hash assignment
5813 mask - Mask assignment
5815 As a general rule, cisco routers support the hash assignment method
5816 and cisco switches support the mask assignment method.
5821 LOC: Config.Wccp2.info
5822 DEFAULT_IF_NONE: standard 0
5825 WCCP2 allows for multiple traffic services. There are two
5826 types: "standard" and "dynamic". The standard type defines
5827 one service id - http (id 0). The dynamic service ids can be from
5828 51 to 255 inclusive. In order to use a dynamic service id
5829 one must define the type of traffic to be redirected; this is done
5830 using the wccp2_service_info option.
5832 The "standard" type does not require a wccp2_service_info option,
5833 just specifying the service id will suffice.
5835 MD5 service authentication can be enabled by adding
5836 "password=<password>" to the end of this service declaration.
5840 wccp2_service standard 0 # for the 'web-cache' standard service
5841 wccp2_service dynamic 80 # a dynamic service type which will be
5842 # fleshed out with subsequent options.
5843 wccp2_service standard 0 password=foo
5846 NAME: wccp2_service_info
5847 TYPE: wccp2_service_info
5848 LOC: Config.Wccp2.info
5852 Dynamic WCCPv2 services require further information to define the
5853 traffic you wish to have diverted.
5857 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
5858 priority=<priority> ports=<port>,<port>..
5860 The relevant WCCPv2 flags:
5861 + src_ip_hash, dst_ip_hash
5862 + source_port_hash, dst_port_hash
5863 + src_ip_alt_hash, dst_ip_alt_hash
5864 + src_port_alt_hash, dst_port_alt_hash
5867 The port list can be one to eight entries.
5871 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
5872 priority=240 ports=80
5874 Note: the service id must have been defined by a previous
5875 'wccp2_service dynamic <id>' entry.
5880 LOC: Config.Wccp2.weight
5884 Each cache server gets assigned a set of the destination
5885 hash proportional to their weight.
5890 LOC: Config.Wccp.address
5897 LOC: Config.Wccp2.address
5901 Use this option if you require WCCP to use a specific
5904 The default behavior is to not bind to any specific address.
5908 PERSISTENT CONNECTION HANDLING
5909 -----------------------------------------------------------------------------
5911 Also see "pconn_timeout" in the TIMEOUTS section
5914 NAME: client_persistent_connections
5916 LOC: Config.onoff.client_pconns
5920 NAME: server_persistent_connections
5922 LOC: Config.onoff.server_pconns
5925 Persistent connection support for clients and servers. By
5926 default, Squid uses persistent connections (when allowed)
5927 with its clients and servers. You can use these options to
5928 disable persistent connections with clients and/or servers.
5931 NAME: persistent_connection_after_error
5933 LOC: Config.onoff.error_pconns
5936 With this directive the use of persistent connections after
5937 HTTP errors can be disabled. Useful if you have clients
5938 who fail to handle errors on persistent connections proper.
5941 NAME: detect_broken_pconn
5943 LOC: Config.onoff.detect_broken_server_pconns
5946 Some servers have been found to incorrectly signal the use
5947 of HTTP/1.0 persistent connections even on replies not
5948 compatible, causing significant delays. This server problem
5949 has mostly been seen on redirects.
5951 By enabling this directive Squid attempts to detect such
5952 broken replies and automatically assume the reply is finished
5953 after 10 seconds timeout.
5957 CACHE DIGEST OPTIONS
5958 -----------------------------------------------------------------------------
5961 NAME: digest_generation
5962 IFDEF: USE_CACHE_DIGESTS
5964 LOC: Config.onoff.digest_generation
5967 This controls whether the server will generate a Cache Digest
5968 of its contents. By default, Cache Digest generation is
5969 enabled if Squid is compiled with --enable-cache-digests defined.
5972 NAME: digest_bits_per_entry
5973 IFDEF: USE_CACHE_DIGESTS
5975 LOC: Config.digest.bits_per_entry
5978 This is the number of bits of the server's Cache Digest which
5979 will be associated with the Digest entry for a given HTTP
5980 Method and URL (public key) combination. The default is 5.
5983 NAME: digest_rebuild_period
5984 IFDEF: USE_CACHE_DIGESTS
5987 LOC: Config.digest.rebuild_period
5990 This is the wait time between Cache Digest rebuilds.
5993 NAME: digest_rewrite_period
5995 IFDEF: USE_CACHE_DIGESTS
5997 LOC: Config.digest.rewrite_period
6000 This is the wait time between Cache Digest writes to
6004 NAME: digest_swapout_chunk_size
6007 IFDEF: USE_CACHE_DIGESTS
6008 LOC: Config.digest.swapout_chunk_size
6011 This is the number of bytes of the Cache Digest to write to
6012 disk at a time. It defaults to 4096 bytes (4KB), the Squid
6016 NAME: digest_rebuild_chunk_percentage
6017 COMMENT: (percent, 0-100)
6018 IFDEF: USE_CACHE_DIGESTS
6020 LOC: Config.digest.rebuild_chunk_percentage
6023 This is the percentage of the Cache Digest to be scanned at a
6024 time. By default it is set to 10% of the Cache Digest.
6029 -----------------------------------------------------------------------------
6034 LOC: Config.Port.snmp
6038 The port number where Squid listens for SNMP requests. To enable
6039 SNMP support set this to a suitable port number. Port number
6040 3401 is often used for the Squid SNMP agent. By default it's
6041 set to "0" (disabled)
6049 LOC: Config.accessList.snmp
6050 DEFAULT_IF_NONE: deny all
6053 Allowing or denying access to the SNMP port.
6055 All access to the agent is denied by default.
6058 snmp_access allow|deny [!]aclname ...
6060 This clause only supports fast acl types.
6061 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6063 snmp_access allow snmppublic localhost
6064 snmp_access deny all
6067 NAME: snmp_incoming_address
6069 LOC: Config.Addrs.snmp_incoming
6074 NAME: snmp_outgoing_address
6076 LOC: Config.Addrs.snmp_outgoing
6080 Just like 'udp_incoming_address', but for the SNMP port.
6082 snmp_incoming_address is used for the SNMP socket receiving
6083 messages from SNMP agents.
6084 snmp_outgoing_address is used for SNMP packets returned to SNMP
6087 The default snmp_incoming_address is to listen on all
6088 available network interfaces.
6090 If snmp_outgoing_address is not set it will use the same socket
6091 as snmp_incoming_address. Only change this if you want to have
6092 SNMP replies sent using another address than where this Squid
6093 listens for SNMP queries.
6095 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
6096 the same value since they both use port 3401.
6101 -----------------------------------------------------------------------------
6104 NAME: icp_port udp_port
6107 LOC: Config.Port.icp
6109 The port number where Squid sends and receives ICP queries to
6110 and from neighbor caches. The standard UDP port for ICP is 3130.
6111 Default is disabled (0).
6114 icp_port @DEFAULT_ICP_PORT@
6121 LOC: Config.Port.htcp
6123 The port number where Squid sends and receives HTCP queries to
6124 and from neighbor caches. To turn it on you want to set it to
6125 4827. By default it is set to "0" (disabled).
6131 NAME: log_icp_queries
6135 LOC: Config.onoff.log_udp
6137 If set, ICP queries are logged to access.log. You may wish
6138 do disable this if your ICP load is VERY high to speed things
6139 up or to simplify log analysis.
6142 NAME: udp_incoming_address
6144 LOC:Config.Addrs.udp_incoming
6147 udp_incoming_address is used for UDP packets received from other
6150 The default behavior is to not bind to any specific address.
6152 Only change this if you want to have all UDP queries received on
6153 a specific interface/address.
6155 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
6156 modules. Altering it will affect all of them in the same manner.
6158 see also; udp_outgoing_address
6160 NOTE, udp_incoming_address and udp_outgoing_address can not
6161 have the same value since they both use the same port.
6164 NAME: udp_outgoing_address
6166 LOC: Config.Addrs.udp_outgoing
6169 udp_outgoing_address is used for UDP packets sent out to other
6172 The default behavior is to not bind to any specific address.
6174 Instead it will use the same socket as udp_incoming_address.
6175 Only change this if you want to have UDP queries sent using another
6176 address than where this Squid listens for UDP queries from other
6179 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
6180 modules. Altering it will affect all of them in the same manner.
6182 see also; udp_incoming_address
6184 NOTE, udp_incoming_address and udp_outgoing_address can not
6185 have the same value since they both use the same port.
6192 LOC: Config.onoff.icp_hit_stale
6194 If you want to return ICP_HIT for stale cache objects, set this
6195 option to 'on'. If you have sibling relationships with caches
6196 in other administrative domains, this should be 'off'. If you only
6197 have sibling relationships with caches under your control,
6198 it is probably okay to set this to 'on'.
6199 If set to 'on', your siblings should use the option "allow-miss"
6200 on their cache_peer lines for connecting to you.
6203 NAME: minimum_direct_hops
6206 LOC: Config.minDirectHops
6208 If using the ICMP pinging stuff, do direct fetches for sites
6209 which are no more than this many hops away.
6212 NAME: minimum_direct_rtt
6215 LOC: Config.minDirectRtt
6217 If using the ICMP pinging stuff, do direct fetches for sites
6218 which are no more than this many rtt milliseconds away.
6224 LOC: Config.Netdb.low
6230 LOC: Config.Netdb.high
6232 The low and high water marks for the ICMP measurement
6233 database. These are counts, not percents. The defaults are
6234 900 and 1000. When the high water mark is reached, database
6235 entries will be deleted until the low mark is reached.
6238 NAME: netdb_ping_period
6240 LOC: Config.Netdb.period
6243 The minimum period for measuring a site. There will be at
6244 least this much delay between successive pings to the same
6245 network. The default is five minutes.
6252 LOC: Config.onoff.query_icmp
6254 If you want to ask your peers to include ICMP data in their ICP
6255 replies, enable this option.
6257 If your peer has configured Squid (during compilation) with
6258 '--enable-icmp' that peer will send ICMP pings to origin server
6259 sites of the URLs it receives. If you enable this option the
6260 ICP replies from that peer will include the ICMP data (if available).
6261 Then, when choosing a parent cache, Squid will choose the parent with
6262 the minimal RTT to the origin server. When this happens, the
6263 hierarchy field of the access.log will be
6264 "CLOSEST_PARENT_MISS". This option is off by default.
6267 NAME: test_reachability
6271 LOC: Config.onoff.test_reachability
6273 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
6274 instead of ICP_MISS if the target host is NOT in the ICMP
6275 database, or has a zero RTT.
6278 NAME: icp_query_timeout
6282 LOC: Config.Timeout.icp_query
6284 Normally Squid will automatically determine an optimal ICP
6285 query timeout value based on the round-trip-time of recent ICP
6286 queries. If you want to override the value determined by
6287 Squid, set this 'icp_query_timeout' to a non-zero value. This
6288 value is specified in MILLISECONDS, so, to use a 2-second
6289 timeout (the old default), you would write:
6291 icp_query_timeout 2000
6294 NAME: maximum_icp_query_timeout
6298 LOC: Config.Timeout.icp_query_max
6300 Normally the ICP query timeout is determined dynamically. But
6301 sometimes it can lead to very large values (say 5 seconds).
6302 Use this option to put an upper limit on the dynamic timeout
6303 value. Do NOT use this option to always use a fixed (instead
6304 of a dynamic) timeout value. To set a fixed timeout see the
6305 'icp_query_timeout' directive.
6308 NAME: minimum_icp_query_timeout
6312 LOC: Config.Timeout.icp_query_min
6314 Normally the ICP query timeout is determined dynamically. But
6315 sometimes it can lead to very small timeouts, even lower than
6316 the normal latency variance on your link due to traffic.
6317 Use this option to put an lower limit on the dynamic timeout
6318 value. Do NOT use this option to always use a fixed (instead
6319 of a dynamic) timeout value. To set a fixed timeout see the
6320 'icp_query_timeout' directive.
6323 NAME: background_ping_rate
6327 LOC: Config.backgroundPingRate
6329 Controls how often the ICP pings are sent to siblings that
6330 have background-ping set.
6334 MULTICAST ICP OPTIONS
6335 -----------------------------------------------------------------------------
6340 LOC: Config.mcast_group_list
6343 This tag specifies a list of multicast groups which your server
6344 should join to receive multicasted ICP queries.
6346 NOTE! Be very careful what you put here! Be sure you
6347 understand the difference between an ICP _query_ and an ICP
6348 _reply_. This option is to be set only if you want to RECEIVE
6349 multicast queries. Do NOT set this option to SEND multicast
6350 ICP (use cache_peer for that). ICP replies are always sent via
6351 unicast, so this option does not affect whether or not you will
6352 receive replies from multicast group members.
6354 You must be very careful to NOT use a multicast address which
6355 is already in use by another group of caches.
6357 If you are unsure about multicast, please read the Multicast
6358 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
6360 Usage: mcast_groups 239.128.16.128 224.0.1.20
6362 By default, Squid doesn't listen on any multicast groups.
6365 NAME: mcast_miss_addr
6366 IFDEF: MULTICAST_MISS_STREAM
6368 LOC: Config.mcast_miss.addr
6371 If you enable this option, every "cache miss" URL will
6372 be sent out on the specified multicast address.
6374 Do not enable this option unless you are are absolutely
6375 certain you understand what you are doing.
6378 NAME: mcast_miss_ttl
6379 IFDEF: MULTICAST_MISS_STREAM
6381 LOC: Config.mcast_miss.ttl
6384 This is the time-to-live value for packets multicasted
6385 when multicasting off cache miss URLs is enabled. By
6386 default this is set to 'site scope', i.e. 16.
6389 NAME: mcast_miss_port
6390 IFDEF: MULTICAST_MISS_STREAM
6392 LOC: Config.mcast_miss.port
6395 This is the port number to be used in conjunction with
6399 NAME: mcast_miss_encode_key
6400 IFDEF: MULTICAST_MISS_STREAM
6402 LOC: Config.mcast_miss.encode_key
6403 DEFAULT: XXXXXXXXXXXXXXXX
6405 The URLs that are sent in the multicast miss stream are
6406 encrypted. This is the encryption key.
6409 NAME: mcast_icp_query_timeout
6413 LOC: Config.Timeout.mcast_icp_query
6415 For multicast peers, Squid regularly sends out ICP "probes" to
6416 count how many other peers are listening on the given multicast
6417 address. This value specifies how long Squid should wait to
6418 count all the replies. The default is 2000 msec, or 2
6423 INTERNAL ICON OPTIONS
6424 -----------------------------------------------------------------------------
6427 NAME: icon_directory
6429 LOC: Config.icons.directory
6430 DEFAULT: @DEFAULT_ICON_DIR@
6432 Where the icons are stored. These are normally kept in
6436 NAME: global_internal_static
6438 LOC: Config.onoff.global_internal_static
6441 This directive controls is Squid should intercept all requests for
6442 /squid-internal-static/ no matter which host the URL is requesting
6443 (default on setting), or if nothing special should be done for
6444 such URLs (off setting). The purpose of this directive is to make
6445 icons etc work better in complex cache hierarchies where it may
6446 not always be possible for all corners in the cache mesh to reach
6447 the server generating a directory listing.
6450 NAME: short_icon_urls
6452 LOC: Config.icons.use_short_names
6455 If this is enabled Squid will use short URLs for icons.
6456 If disabled it will revert to the old behavior of including
6457 it's own name and port in the URL.
6459 If you run a complex cache hierarchy with a mix of Squid and
6460 other proxies you may need to disable this directive.
6465 -----------------------------------------------------------------------------
6468 NAME: error_directory
6470 LOC: Config.errorDirectory
6473 If you wish to create your own versions of the default
6474 error files to customize them to suit your company copy
6475 the error/template files to another directory and point
6478 WARNING: This option will disable multi-language support
6479 on error pages if used.
6481 The squid developers are interested in making squid available in
6482 a wide variety of languages. If you are making translations for a
6483 language that Squid does not currently provide please consider
6484 contributing your translation back to the project.
6485 http://wiki.squid-cache.org/Translations
6487 The squid developers working on translations are happy to supply drop-in
6488 translated error files in exchange for any new language contributions.
6491 NAME: error_default_language
6492 IFDEF: USE_ERR_LOCALES
6494 LOC: Config.errorDefaultLanguage
6497 Set the default language which squid will send error pages in
6498 if no existing translation matches the clients language
6501 If unset (default) generic English will be used.
6503 The squid developers are interested in making squid available in
6504 a wide variety of languages. If you are interested in making
6505 translations for any language see the squid wiki for details.
6506 http://wiki.squid-cache.org/Translations
6509 NAME: error_log_languages
6510 IFDEF: USE_ERR_LOCALES
6512 LOC: Config.errorLogMissingLanguages
6515 Log to cache.log what languages users are attempting to
6516 auto-negotiate for translations.
6518 Successful negotiations are not logged. Only failures
6519 have meaning to indicate that Squid may need an upgrade
6520 of its error page translations.
6523 NAME: err_page_stylesheet
6525 LOC: Config.errorStylesheet
6526 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
6528 CSS Stylesheet to pattern the display of Squid default error pages.
6530 For information on CSS see http://www.w3.org/Style/CSS/
6535 LOC: Config.errHtmlText
6538 HTML text to include in error messages. Make this a "mailto"
6539 URL to your admin address, or maybe just a link to your
6540 organizations Web page.
6542 To include this in your error messages, you must rewrite
6543 the error template files (found in the "errors" directory).
6544 Wherever you want the 'err_html_text' line to appear,
6545 insert a %L tag in the error template file.
6548 NAME: email_err_data
6551 LOC: Config.onoff.emailErrData
6554 If enabled, information about the occurred error will be
6555 included in the mailto links of the ERR pages (if %W is set)
6556 so that the email body contains the data.
6557 Syntax is <A HREF="mailto:%w%W">%w</A>
6562 LOC: Config.denyInfoList
6565 Usage: deny_info err_page_name acl
6566 or deny_info http://... acl
6567 or deny_info TCP_RESET acl
6569 This can be used to return a ERR_ page for requests which
6570 do not pass the 'http_access' rules. Squid remembers the last
6571 acl it evaluated in http_access, and if a 'deny_info' line exists
6572 for that ACL Squid returns a corresponding error page.
6574 The acl is typically the last acl on the http_access deny line which
6575 denied access. The exceptions to this rule are:
6576 - When Squid needs to request authentication credentials. It's then
6577 the first authentication related acl encountered
6578 - When none of the http_access lines matches. It's then the last
6579 acl processed on the last http_access line.
6580 - When the decision to deny access was made by an adaptation service,
6581 the acl name is the corresponding eCAP or ICAP service_name.
6583 NP: If providing your own custom error pages with error_directory
6584 you may also specify them by your custom file name:
6585 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
6587 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
6588 may be specified by prefixing the file name with the code and a colon.
6589 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
6591 Alternatively you can tell Squid to reset the TCP connection
6592 by specifying TCP_RESET.
6594 Or you can specify an error URL or URL pattern. The browsers will
6595 get redirected to the specified URL after formatting tags have
6596 been replaced. Redirect will be done with 302 or 307 according to
6597 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
6598 the URL. e.g. 303:http://example.com/
6601 %a - username (if available. Password NOT included)
6604 %E - Error description
6606 %H - Request domain name
6607 %i - Client IP Address
6609 %o - Message result from external ACL helper
6610 %p - Request Port number
6611 %P - Request Protocol name
6612 %R - Request URL path
6613 %T - Timestamp in RFC 1123 format
6614 %U - Full canonical URL from client
6615 (HTTPS URLs terminate with *)
6616 %u - Full canonical URL from client
6617 %w - Admin email from squid.conf
6619 %% - Literal percent (%) code
6624 OPTIONS INFLUENCING REQUEST FORWARDING
6625 -----------------------------------------------------------------------------
6628 NAME: nonhierarchical_direct
6630 LOC: Config.onoff.nonhierarchical_direct
6633 By default, Squid will send any non-hierarchical requests
6634 (matching hierarchy_stoplist or not cacheable request type) direct
6637 If you set this to off, Squid will prefer to send these
6638 requests to parents.
6640 Note that in most configurations, by turning this off you will only
6641 add latency to these request without any improvement in global hit
6644 If you are inside an firewall see never_direct instead of
6650 LOC: Config.onoff.prefer_direct
6653 Normally Squid tries to use parents for most requests. If you for some
6654 reason like it to first try going direct and only use a parent if
6655 going direct fails set this to on.
6657 By combining nonhierarchical_direct off and prefer_direct on you
6658 can set up Squid to use a parent as a backup path if going direct
6661 Note: If you want Squid to use parents for all requests see
6662 the never_direct directive. prefer_direct only modifies how Squid
6663 acts on cacheable requests.
6668 LOC: Config.accessList.AlwaysDirect
6671 Usage: always_direct allow|deny [!]aclname ...
6673 Here you can use ACL elements to specify requests which should
6674 ALWAYS be forwarded by Squid to the origin servers without using
6675 any peers. For example, to always directly forward requests for
6676 local servers ignoring any parents or siblings you may have use
6679 acl local-servers dstdomain my.domain.net
6680 always_direct allow local-servers
6682 To always forward FTP requests directly, use
6685 always_direct allow FTP
6687 NOTE: There is a similar, but opposite option named
6688 'never_direct'. You need to be aware that "always_direct deny
6689 foo" is NOT the same thing as "never_direct allow foo". You
6690 may need to use a deny rule to exclude a more-specific case of
6691 some other rule. Example:
6693 acl local-external dstdomain external.foo.net
6694 acl local-servers dstdomain .foo.net
6695 always_direct deny local-external
6696 always_direct allow local-servers
6698 NOTE: If your goal is to make the client forward the request
6699 directly to the origin server bypassing Squid then this needs
6700 to be done in the client configuration. Squid configuration
6701 can only tell Squid how Squid should fetch the object.
6703 NOTE: This directive is not related to caching. The replies
6704 is cached as usual even if you use always_direct. To not cache
6705 the replies see the 'cache' directive.
6707 This clause supports both fast and slow acl types.
6708 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6713 LOC: Config.accessList.NeverDirect
6716 Usage: never_direct allow|deny [!]aclname ...
6718 never_direct is the opposite of always_direct. Please read
6719 the description for always_direct if you have not already.
6721 With 'never_direct' you can use ACL elements to specify
6722 requests which should NEVER be forwarded directly to origin
6723 servers. For example, to force the use of a proxy for all
6724 requests, except those in your local domain use something like:
6726 acl local-servers dstdomain .foo.net
6727 never_direct deny local-servers
6728 never_direct allow all
6730 or if Squid is inside a firewall and there are local intranet
6731 servers inside the firewall use something like:
6733 acl local-intranet dstdomain .foo.net
6734 acl local-external dstdomain external.foo.net
6735 always_direct deny local-external
6736 always_direct allow local-intranet
6737 never_direct allow all
6739 This clause supports both fast and slow acl types.
6740 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6744 ADVANCED NETWORKING OPTIONS
6745 -----------------------------------------------------------------------------
6748 NAME: incoming_udp_average incoming_icp_average
6751 LOC: Config.comm_incoming.udp.average
6753 Heavy voodoo here. I can't even believe you are reading this.
6754 Are you crazy? Don't even think about adjusting these unless
6755 you understand the algorithms in comm_select.c first!
6758 NAME: incoming_tcp_average incoming_http_average
6761 LOC: Config.comm_incoming.tcp.average
6763 Heavy voodoo here. I can't even believe you are reading this.
6764 Are you crazy? Don't even think about adjusting these unless
6765 you understand the algorithms in comm_select.c first!
6768 NAME: incoming_dns_average
6771 LOC: Config.comm_incoming.dns.average
6773 Heavy voodoo here. I can't even believe you are reading this.
6774 Are you crazy? Don't even think about adjusting these unless
6775 you understand the algorithms in comm_select.c first!
6778 NAME: min_udp_poll_cnt min_icp_poll_cnt
6781 LOC: Config.comm_incoming.udp.min_poll
6783 Heavy voodoo here. I can't even believe you are reading this.
6784 Are you crazy? Don't even think about adjusting these unless
6785 you understand the algorithms in comm_select.c first!
6788 NAME: min_dns_poll_cnt
6791 LOC: Config.comm_incoming.dns.min_poll
6793 Heavy voodoo here. I can't even believe you are reading this.
6794 Are you crazy? Don't even think about adjusting these unless
6795 you understand the algorithms in comm_select.c first!
6798 NAME: min_tcp_poll_cnt min_http_poll_cnt
6801 LOC: Config.comm_incoming.tcp.min_poll
6803 Heavy voodoo here. I can't even believe you are reading this.
6804 Are you crazy? Don't even think about adjusting these unless
6805 you understand the algorithms in comm_select.c first!
6811 LOC: Config.accept_filter
6815 The name of an accept(2) filter to install on Squid's
6816 listen socket(s). This feature is perhaps specific to
6817 FreeBSD and requires support in the kernel.
6819 The 'httpready' filter delays delivering new connections
6820 to Squid until a full HTTP request has been received.
6821 See the accf_http(9) man page for details.
6823 The 'dataready' filter delays delivering new connections
6824 to Squid until there is some data to process.
6825 See the accf_dataready(9) man page for details.
6829 The 'data' filter delays delivering of new connections
6830 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
6831 You may optionally specify a number of seconds to wait by
6832 'data=N' where N is the number of seconds. Defaults to 30
6833 if not specified. See the tcp(7) man page for details.
6836 accept_filter httpready
6841 NAME: client_ip_max_connections
6843 LOC: Config.client_ip_max_connections
6846 Set an absolute limit on the number of connections a single
6847 client IP can use. Any more than this and Squid will begin to drop
6848 new connections from the client until it closes some links.
6850 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
6851 connections from the client. For finer control use the ACL access controls.
6853 Requires client_db to be enabled (the default).
6855 WARNING: This may noticably slow down traffic received via external proxies
6856 or NAT devices and cause them to rebound error messages back to their clients.
6859 NAME: tcp_recv_bufsize
6863 LOC: Config.tcpRcvBufsz
6865 Size of receive buffer to set for TCP sockets. Probably just
6866 as easy to change your kernel's default. Set to zero to use
6867 the default buffer size.
6872 -----------------------------------------------------------------------------
6879 LOC: Adaptation::Icap::TheConfig.onoff
6882 If you want to enable the ICAP module support, set this to on.
6885 NAME: icap_connect_timeout
6888 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
6891 This parameter specifies how long to wait for the TCP connect to
6892 the requested ICAP server to complete before giving up and either
6893 terminating the HTTP transaction or bypassing the failure.
6895 The default for optional services is peer_connect_timeout.
6896 The default for essential services is connect_timeout.
6897 If this option is explicitly set, its value applies to all services.
6900 NAME: icap_io_timeout
6904 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
6907 This parameter specifies how long to wait for an I/O activity on
6908 an established, active ICAP connection before giving up and
6909 either terminating the HTTP transaction or bypassing the
6912 The default is read_timeout.
6915 NAME: icap_service_failure_limit
6916 COMMENT: limit [in memory-depth time-units]
6917 TYPE: icap_service_failure_limit
6919 LOC: Adaptation::Icap::TheConfig
6922 The limit specifies the number of failures that Squid tolerates
6923 when establishing a new TCP connection with an ICAP service. If
6924 the number of failures exceeds the limit, the ICAP service is
6925 not used for new ICAP requests until it is time to refresh its
6928 A negative value disables the limit. Without the limit, an ICAP
6929 service will not be considered down due to connectivity failures
6930 between ICAP OPTIONS requests.
6932 Squid forgets ICAP service failures older than the specified
6933 value of memory-depth. The memory fading algorithm
6934 is approximate because Squid does not remember individual
6935 errors but groups them instead, splitting the option
6936 value into ten time slots of equal length.
6938 When memory-depth is 0 and by default this option has no
6939 effect on service failure expiration.
6941 Squid always forgets failures when updating service settings
6942 using an ICAP OPTIONS transaction, regardless of this option
6946 # suspend service usage after 10 failures in 5 seconds:
6947 icap_service_failure_limit 10 in 5 seconds
6950 NAME: icap_service_revival_delay
6953 LOC: Adaptation::Icap::TheConfig.service_revival_delay
6956 The delay specifies the number of seconds to wait after an ICAP
6957 OPTIONS request failure before requesting the options again. The
6958 failed ICAP service is considered "down" until fresh OPTIONS are
6961 The actual delay cannot be smaller than the hardcoded minimum
6962 delay of 30 seconds.
6965 NAME: icap_preview_enable
6969 LOC: Adaptation::Icap::TheConfig.preview_enable
6972 The ICAP Preview feature allows the ICAP server to handle the
6973 HTTP message by looking only at the beginning of the message body
6974 or even without receiving the body at all. In some environments,
6975 previews greatly speedup ICAP processing.
6977 During an ICAP OPTIONS transaction, the server may tell Squid what
6978 HTTP messages should be previewed and how big the preview should be.
6979 Squid will not use Preview if the server did not request one.
6981 To disable ICAP Preview for all ICAP services, regardless of
6982 individual ICAP server OPTIONS responses, set this option to "off".
6984 icap_preview_enable off
6987 NAME: icap_preview_size
6990 LOC: Adaptation::Icap::TheConfig.preview_size
6993 The default size of preview data to be sent to the ICAP server.
6994 -1 means no preview. This value might be overwritten on a per server
6995 basis by OPTIONS requests.
6998 NAME: icap_206_enable
7002 LOC: Adaptation::Icap::TheConfig.allow206_enable
7005 206 (Partial Content) responses is an ICAP extension that allows the
7006 ICAP agents to optionally combine adapted and original HTTP message
7007 content. The decision to combine is postponed until the end of the
7008 ICAP response. Squid supports Partial Content extension by default.
7010 Activation of the Partial Content extension is negotiated with each
7011 ICAP service during OPTIONS exchange. Most ICAP servers should handle
7012 negotation correctly even if they do not support the extension, but
7013 some might fail. To disable Partial Content support for all ICAP
7014 services and to avoid any negotiation, set this option to "off".
7020 NAME: icap_default_options_ttl
7023 LOC: Adaptation::Icap::TheConfig.default_options_ttl
7026 The default TTL value for ICAP OPTIONS responses that don't have
7027 an Options-TTL header.
7030 NAME: icap_persistent_connections
7034 LOC: Adaptation::Icap::TheConfig.reuse_connections
7037 Whether or not Squid should use persistent connections to
7041 NAME: adaptation_send_client_ip icap_send_client_ip
7043 IFDEF: USE_ADAPTATION
7045 LOC: Adaptation::Config::send_client_ip
7048 If enabled, Squid shares HTTP client IP information with adaptation
7049 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
7050 For eCAP, Squid sets the libecap::metaClientIp transaction option.
7052 See also: adaptation_uses_indirect_client
7055 NAME: adaptation_send_username icap_send_client_username
7057 IFDEF: USE_ADAPTATION
7059 LOC: Adaptation::Config::send_username
7062 This sends authenticated HTTP client username (if available) to
7063 the adaptation service.
7065 For ICAP, the username value is encoded based on the
7066 icap_client_username_encode option and is sent using the header
7067 specified by the icap_client_username_header option.
7070 NAME: icap_client_username_header
7073 LOC: Adaptation::Icap::TheConfig.client_username_header
7074 DEFAULT: X-Client-Username
7076 ICAP request header name to use for adaptation_send_username.
7079 NAME: icap_client_username_encode
7083 LOC: Adaptation::Icap::TheConfig.client_username_encode
7086 Whether to base64 encode the authenticated client username.
7090 TYPE: icap_service_type
7092 LOC: Adaptation::Icap::TheConfig
7095 Defines a single ICAP service using the following format:
7097 icap_service id vectoring_point uri [option ...]
7100 an opaque identifier or name which is used to direct traffic to
7101 this specific service. Must be unique among all adaptation
7102 services in squid.conf.
7104 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7105 This specifies at which point of transaction processing the
7106 ICAP service should be activated. *_postcache vectoring points
7107 are not yet supported.
7109 uri: icap://servername:port/servicepath
7110 ICAP server and service location.
7112 ICAP does not allow a single service to handle both REQMOD and RESPMOD
7113 transactions. Squid does not enforce that requirement. You can specify
7114 services with the same service_url and different vectoring_points. You
7115 can even specify multiple identical services as long as their
7116 service_names differ.
7119 Service options are separated by white space. ICAP services support
7120 the following name=value options:
7123 If set to 'on' or '1', the ICAP service is treated as
7124 optional. If the service cannot be reached or malfunctions,
7125 Squid will try to ignore any errors and process the message as
7126 if the service was not enabled. No all ICAP errors can be
7127 bypassed. If set to 0, the ICAP service is treated as
7128 essential and all ICAP errors will result in an error page
7129 returned to the HTTP client.
7131 Bypass is off by default: services are treated as essential.
7134 If set to 'on' or '1', the ICAP service is allowed to
7135 dynamically change the current message adaptation plan by
7136 returning a chain of services to be used next. The services
7137 are specified using the X-Next-Services ICAP response header
7138 value, formatted as a comma-separated list of service names.
7139 Each named service should be configured in squid.conf. Other
7140 services are ignored. An empty X-Next-Services value results
7141 in an empty plan which ends the current adaptation.
7143 Dynamic adaptation plan may cross or cover multiple supported
7144 vectoring points in their natural processing order.
7146 Routing is not allowed by default: the ICAP X-Next-Services
7147 response header is ignored.
7150 Only has effect on split-stack systems. The default on those systems
7151 is to use IPv4-only connections. When set to 'on' this option will
7152 make Squid use IPv6-only connections to contact this ICAP service.
7154 on-overload=block|bypass|wait|force
7155 If the service Max-Connections limit has been reached, do
7156 one of the following for each new ICAP transaction:
7157 * block: send an HTTP error response to the client
7158 * bypass: ignore the "over-connected" ICAP service
7159 * wait: wait (in a FIFO queue) for an ICAP connection slot
7160 * force: proceed, ignoring the Max-Connections limit
7162 In SMP mode with N workers, each worker assumes the service
7163 connection limit is Max-Connections/N, even though not all
7164 workers may use a given service.
7166 The default value is "bypass" if service is bypassable,
7167 otherwise it is set to "wait".
7171 Use the given number as the Max-Connections limit, regardless
7172 of the Max-Connections value given by the service, if any.
7174 Older icap_service format without optional named parameters is
7175 deprecated but supported for backward compatibility.
7178 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
7179 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
7183 TYPE: icap_class_type
7188 This deprecated option was documented to define an ICAP service
7189 chain, even though it actually defined a set of similar, redundant
7190 services, and the chains were not supported.
7192 To define a set of redundant services, please use the
7193 adaptation_service_set directive. For service chains, use
7194 adaptation_service_chain.
7198 TYPE: icap_access_type
7203 This option is deprecated. Please use adaptation_access, which
7204 has the same ICAP functionality, but comes with better
7205 documentation, and eCAP support.
7210 -----------------------------------------------------------------------------
7217 LOC: Adaptation::Ecap::TheConfig.onoff
7220 Controls whether eCAP support is enabled.
7224 TYPE: ecap_service_type
7226 LOC: Adaptation::Ecap::TheConfig
7229 Defines a single eCAP service
7231 ecap_service id vectoring_point uri [option ...]
7234 an opaque identifier or name which is used to direct traffic to
7235 this specific service. Must be unique among all adaptation
7236 services in squid.conf.
7238 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7239 This specifies at which point of transaction processing the
7240 eCAP service should be activated. *_postcache vectoring points
7241 are not yet supported.
7243 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
7244 Squid uses the eCAP service URI to match this configuration
7245 line with one of the dynamically loaded services. Each loaded
7246 eCAP service must have a unique URI. Obtain the right URI from
7247 the service provider.
7250 Service options are separated by white space. eCAP services support
7251 the following name=value options:
7254 If set to 'on' or '1', the eCAP service is treated as optional.
7255 If the service cannot be reached or malfunctions, Squid will try
7256 to ignore any errors and process the message as if the service
7257 was not enabled. No all eCAP errors can be bypassed.
7258 If set to 'off' or '0', the eCAP service is treated as essential
7259 and all eCAP errors will result in an error page returned to the
7262 Bypass is off by default: services are treated as essential.
7265 If set to 'on' or '1', the eCAP service is allowed to
7266 dynamically change the current message adaptation plan by
7267 returning a chain of services to be used next.
7269 Dynamic adaptation plan may cross or cover multiple supported
7270 vectoring points in their natural processing order.
7272 Routing is not allowed by default.
7274 Older ecap_service format without optional named parameters is
7275 deprecated but supported for backward compatibility.
7279 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
7280 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
7283 NAME: loadable_modules
7285 IFDEF: USE_LOADABLE_MODULES
7286 LOC: Config.loadable_module_names
7289 Instructs Squid to load the specified dynamic module(s) or activate
7290 preloaded module(s).
7292 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
7296 MESSAGE ADAPTATION OPTIONS
7297 -----------------------------------------------------------------------------
7300 NAME: adaptation_service_set
7301 TYPE: adaptation_service_set_type
7302 IFDEF: USE_ADAPTATION
7307 Configures an ordered set of similar, redundant services. This is
7308 useful when hot standby or backup adaptation servers are available.
7310 adaptation_service_set set_name service_name1 service_name2 ...
7312 The named services are used in the set declaration order. The first
7313 applicable adaptation service from the set is used first. The next
7314 applicable service is tried if and only if the transaction with the
7315 previous service fails and the message waiting to be adapted is still
7318 When adaptation starts, broken services are ignored as if they were
7319 not a part of the set. A broken service is a down optional service.
7321 The services in a set must be attached to the same vectoring point
7322 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7324 If all services in a set are optional then adaptation failures are
7325 bypassable. If all services in the set are essential, then a
7326 transaction failure with one service may still be retried using
7327 another service from the set, but when all services fail, the master
7328 transaction fails as well.
7330 A set may contain a mix of optional and essential services, but that
7331 is likely to lead to surprising results because broken services become
7332 ignored (see above), making previously bypassable failures fatal.
7333 Technically, it is the bypassability of the last failed service that
7336 See also: adaptation_access adaptation_service_chain
7339 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
7340 adaptation service_set svcLogger loggerLocal loggerRemote
7343 NAME: adaptation_service_chain
7344 TYPE: adaptation_service_chain_type
7345 IFDEF: USE_ADAPTATION
7350 Configures a list of complementary services that will be applied
7351 one-by-one, forming an adaptation chain or pipeline. This is useful
7352 when Squid must perform different adaptations on the same message.
7354 adaptation_service_chain chain_name service_name1 svc_name2 ...
7356 The named services are used in the chain declaration order. The first
7357 applicable adaptation service from the chain is used first. The next
7358 applicable service is applied to the successful adaptation results of
7359 the previous service in the chain.
7361 When adaptation starts, broken services are ignored as if they were
7362 not a part of the chain. A broken service is a down optional service.
7364 Request satisfaction terminates the adaptation chain because Squid
7365 does not currently allow declaration of RESPMOD services at the
7366 "reqmod_precache" vectoring point (see icap_service or ecap_service).
7368 The services in a chain must be attached to the same vectoring point
7369 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7371 A chain may contain a mix of optional and essential services. If an
7372 essential adaptation fails (or the failure cannot be bypassed for
7373 other reasons), the master transaction fails. Otherwise, the failure
7374 is bypassed as if the failed adaptation service was not in the chain.
7376 See also: adaptation_access adaptation_service_set
7379 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
7382 NAME: adaptation_access
7383 TYPE: adaptation_access_type
7384 IFDEF: USE_ADAPTATION
7388 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
7390 adaptation_access service_name allow|deny [!]aclname...
7391 adaptation_access set_name allow|deny [!]aclname...
7393 At each supported vectoring point, the adaptation_access
7394 statements are processed in the order they appear in this
7395 configuration file. Statements pointing to the following services
7396 are ignored (i.e., skipped without checking their ACL):
7398 - services serving different vectoring points
7399 - "broken-but-bypassable" services
7400 - "up" services configured to ignore such transactions
7401 (e.g., based on the ICAP Transfer-Ignore header).
7403 When a set_name is used, all services in the set are checked
7404 using the same rules, to find the first applicable one. See
7405 adaptation_service_set for details.
7407 If an access list is checked and there is a match, the
7408 processing stops: For an "allow" rule, the corresponding
7409 adaptation service is used for the transaction. For a "deny"
7410 rule, no adaptation service is activated.
7412 It is currently not possible to apply more than one adaptation
7413 service at the same vectoring point to the same HTTP transaction.
7415 See also: icap_service and ecap_service
7418 adaptation_access service_1 allow all
7421 NAME: adaptation_service_iteration_limit
7423 IFDEF: USE_ADAPTATION
7424 LOC: Adaptation::Config::service_iteration_limit
7427 Limits the number of iterations allowed when applying adaptation
7428 services to a message. If your longest adaptation set or chain
7429 may have more than 16 services, increase the limit beyond its
7430 default value of 16. If detecting infinite iteration loops sooner
7431 is critical, make the iteration limit match the actual number
7432 of services in your longest adaptation set or chain.
7434 Infinite adaptation loops are most likely with routing services.
7436 See also: icap_service routing=1
7439 NAME: adaptation_masterx_shared_names
7441 IFDEF: USE_ADAPTATION
7442 LOC: Adaptation::Config::masterx_shared_name
7445 For each master transaction (i.e., the HTTP request and response
7446 sequence, including all related ICAP and eCAP exchanges), Squid
7447 maintains a table of metadata. The table entries are (name, value)
7448 pairs shared among eCAP and ICAP exchanges. The table is destroyed
7449 with the master transaction.
7451 This option specifies the table entry names that Squid must accept
7452 from and forward to the adaptation transactions.
7454 An ICAP REQMOD or RESPMOD transaction may set an entry in the
7455 shared table by returning an ICAP header field with a name
7456 specified in adaptation_masterx_shared_names.
7458 An eCAP REQMOD or RESPMOD transaction may set an entry in the
7459 shared table by implementing the libecap::visitEachOption() API
7460 to provide an option with a name specified in
7461 adaptation_masterx_shared_names.
7463 Squid will store and forward the set entry to subsequent adaptation
7464 transactions within the same master transaction scope.
7466 Only one shared entry name is supported at this time.
7469 # share authentication information among ICAP services
7470 adaptation_masterx_shared_names X-Subscriber-ID
7473 NAME: adaptation_meta
7475 IFDEF: USE_ADAPTATION
7476 LOC: Adaptation::Config::metaHeaders
7479 This option allows Squid administrator to add custom ICAP request
7480 headers or eCAP options to Squid ICAP requests or eCAP transactions.
7481 Use it to pass custom authentication tokens and other
7482 transaction-state related meta information to an ICAP/eCAP service.
7484 The addition of a meta header is ACL-driven:
7485 adaptation_meta name value [!]aclname ...
7487 Processing for a given header name stops after the first ACL list match.
7488 Thus, it is impossible to add two headers with the same name. If no ACL
7489 lists match for a given header name, no such header is added. For
7492 # do not debug transactions except for those that need debugging
7493 adaptation_meta X-Debug 1 needs_debugging
7495 # log all transactions except for those that must remain secret
7496 adaptation_meta X-Log 1 !keep_secret
7498 # mark transactions from users in the "G 1" group
7499 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
7501 The "value" parameter may be a regular squid.conf token or a "double
7502 quoted string". Within the quoted string, use backslash (\) to escape
7503 any character, which is currently only useful for escaping backslashes
7504 and double quotes. For example,
7505 "this string has one backslash (\\) and two \"quotes\""
7507 Used adaptation_meta header values may be logged via %note
7508 logformat code. If multiple adaptation_meta headers with the same name
7509 are used during master transaction lifetime, the header values are
7510 logged in the order they were used and duplicate values are ignored
7511 (only the first repeated value will be logged).
7517 LOC: Adaptation::Icap::TheConfig.repeat
7518 DEFAULT_IF_NONE: deny all
7520 This ACL determines which retriable ICAP transactions are
7521 retried. Transactions that received a complete ICAP response
7522 and did not have to consume or produce HTTP bodies to receive
7523 that response are usually retriable.
7525 icap_retry allow|deny [!]aclname ...
7527 Squid automatically retries some ICAP I/O timeouts and errors
7528 due to persistent connection race conditions.
7530 See also: icap_retry_limit
7533 NAME: icap_retry_limit
7536 LOC: Adaptation::Icap::TheConfig.repeat_limit
7539 Limits the number of retries allowed. When set to zero (default),
7540 no retries are allowed.
7542 Communication errors due to persistent connection race
7543 conditions are unavoidable, automatically retried, and do not
7544 count against this limit.
7546 See also: icap_retry
7552 -----------------------------------------------------------------------------
7555 NAME: check_hostnames
7558 LOC: Config.onoff.check_hostnames
7560 For security and stability reasons Squid can check
7561 hostnames for Internet standard RFC compliance. If you want
7562 Squid to perform these checks turn this directive on.
7565 NAME: allow_underscore
7568 LOC: Config.onoff.allow_underscore
7570 Underscore characters is not strictly allowed in Internet hostnames
7571 but nevertheless used by many sites. Set this to off if you want
7572 Squid to be strict about the standard.
7573 This check is performed only when check_hostnames is set to on.
7576 NAME: cache_dns_program
7578 IFDEF: USE_DNSHELPER
7579 DEFAULT: @DEFAULT_DNSSERVER@
7580 LOC: Config.Program.dnsserver
7582 Specify the location of the executable for dnslookup process.
7586 TYPE: HelperChildConfig
7587 IFDEF: USE_DNSHELPER
7588 DEFAULT: 32 startup=1 idle=1
7589 LOC: Config.dnsChildren
7591 The maximum number of processes spawn to service DNS name lookups.
7592 If you limit it too few Squid will have to wait for them to process
7593 a backlog of requests, slowing it down. If you allow too many they
7594 will use RAM and other system resources noticably.
7595 The maximum this may be safely set to is 32.
7597 The startup= and idle= options allow some measure of skew in your
7602 Sets a minimum of how many processes are to be spawned when Squid
7603 starts or reconfigures. When set to zero the first request will
7604 cause spawning of the first child process to handle it.
7606 Starting too few will cause an initial slowdown in traffic as Squid
7607 attempts to simultaneously spawn enough processes to cope.
7611 Sets a minimum of how many processes Squid is to try and keep available
7612 at all times. When traffic begins to rise above what the existing
7613 processes can handle this many more will be spawned up to the maximum
7614 configured. A minimum setting of 1 is required.
7617 NAME: dns_retransmit_interval
7620 LOC: Config.Timeout.idns_retransmit
7621 IFDEF: !USE_DNSHELPER
7623 Initial retransmit interval for DNS queries. The interval is
7624 doubled each time all configured DNS servers have been tried.
7630 LOC: Config.Timeout.idns_query
7631 IFDEF: !USE_DNSHELPER
7633 DNS Query timeout. If no response is received to a DNS query
7634 within this time all DNS servers for the queried domain
7635 are assumed to be unavailable.
7638 NAME: dns_packet_max
7641 LOC: Config.dns.packet_max
7642 IFDEF: !USE_DNSHELPER
7644 Maximum number of bytes packet size to advertise via EDNS.
7645 Set to "none" to disable EDNS large packet support.
7647 For legacy reasons DNS UDP replies will default to 512 bytes which
7648 is too small for many responses. EDNS provides a means for Squid to
7649 negotiate receiving larger responses back immediately without having
7650 to failover with repeat requests. Responses larger than this limit
7651 will retain the old behaviour of failover to TCP DNS.
7653 Squid has no real fixed limit internally, but allowing packet sizes
7654 over 1500 bytes requires network jumbogram support and is usually not
7657 WARNING: The RFC also indicates that some older resolvers will reply
7658 with failure of the whole request if the extension is added. Some
7659 resolvers have already been identified which will reply with mangled
7660 EDNS response on occasion. Usually in response to many-KB jumbogram
7661 sizes being advertised by Squid.
7662 Squid will currently treat these both as an unable-to-resolve domain
7663 even if it would be resolvable without EDNS.
7670 LOC: Config.onoff.res_defnames
7672 Normally the RES_DEFNAMES resolver option is disabled
7673 (see res_init(3)). This prevents caches in a hierarchy
7674 from interpreting single-component hostnames locally. To allow
7675 Squid to handle single-component names, enable this option.
7678 NAME: dns_nameservers
7681 LOC: Config.dns_nameservers
7683 Use this if you want to specify a list of DNS name servers
7684 (IP addresses) to use instead of those given in your
7685 /etc/resolv.conf file.
7686 On Windows platforms, if no value is specified here or in
7687 the /etc/resolv.conf file, the list of DNS name servers are
7688 taken from the Windows registry, both static and dynamic DHCP
7689 configurations are supported.
7691 Example: dns_nameservers 10.0.0.1 192.172.0.4
7696 DEFAULT: @DEFAULT_HOSTS@
7697 LOC: Config.etcHostsPath
7699 Location of the host-local IP name-address associations
7700 database. Most Operating Systems have such a file on different
7702 - Un*X & Linux: /etc/hosts
7703 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
7704 (%SystemRoot% value install default is c:\winnt)
7705 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
7706 (%SystemRoot% value install default is c:\windows)
7707 - Windows 9x/Me: %windir%\hosts
7708 (%windir% value is usually c:\windows)
7709 - Cygwin: /etc/hosts
7711 The file contains newline-separated definitions, in the
7712 form ip_address_in_dotted_form name [name ...] names are
7713 whitespace-separated. Lines beginning with an hash (#)
7714 character are comments.
7716 The file is checked at startup and upon configuration.
7717 If set to 'none', it won't be checked.
7718 If append_domain is used, that domain will be added to
7719 domain-local (i.e. not containing any dot character) host
7725 LOC: Config.appendDomain
7728 Appends local domain name to hostnames without any dots in
7729 them. append_domain must begin with a period.
7731 Be warned there are now Internet names with no dots in
7732 them using only top-domain names, so setting this may
7733 cause some Internet sites to become unavailable.
7736 append_domain .yourdomain.com
7739 NAME: ignore_unknown_nameservers
7741 LOC: Config.onoff.ignore_unknown_nameservers
7743 IFDEF: !USE_DNSHELPER
7745 By default Squid checks that DNS responses are received
7746 from the same IP addresses they are sent to. If they
7747 don't match, Squid ignores the response and writes a warning
7748 message to cache.log. You can allow responses from unknown
7749 nameservers by setting this option to 'off'.
7755 LOC: Config.dns.v4_first
7756 IFDEF: !USE_DNSHELPER
7758 With the IPv6 Internet being as fast or faster than IPv4 Internet
7759 for most networks Squid prefers to contact websites over IPv6.
7761 This option reverses the order of preference to make Squid contact
7762 dual-stack websites over IPv4 first. Squid will still perform both
7763 IPv6 and IPv4 DNS lookups before connecting.
7766 This option will restrict the situations under which IPv6
7767 connectivity is used (and tested). Hiding network problems
7768 which would otherwise be detected and warned about.
7772 COMMENT: (number of entries)
7775 LOC: Config.ipcache.size
7782 LOC: Config.ipcache.low
7789 LOC: Config.ipcache.high
7791 The size, low-, and high-water marks for the IP cache.
7794 NAME: fqdncache_size
7795 COMMENT: (number of entries)
7798 LOC: Config.fqdncache.size
7800 Maximum number of FQDN cache entries.
7805 -----------------------------------------------------------------------------
7812 LOC: Config.onoff.mem_pools
7814 If set, Squid will keep pools of allocated (but unused) memory
7815 available for future use. If memory is a premium on your
7816 system and you believe your malloc library outperforms Squid
7817 routines, disable this.
7820 NAME: memory_pools_limit
7824 LOC: Config.MemPools.limit
7826 Used only with memory_pools on:
7827 memory_pools_limit 50 MB
7829 If set to a non-zero value, Squid will keep at most the specified
7830 limit of allocated (but unused) memory in memory pools. All free()
7831 requests that exceed this limit will be handled by your malloc
7832 library. Squid does not pre-allocate any memory, just safe-keeps
7833 objects that otherwise would be free()d. Thus, it is safe to set
7834 memory_pools_limit to a reasonably high value even if your
7835 configuration will use less memory.
7837 If set to none, Squid will keep all memory it can. That is, there
7838 will be no limit on the total amount of memory used for safe-keeping.
7840 To disable memory allocation optimization, do not set
7841 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
7843 An overhead for maintaining memory pools is not taken into account
7844 when the limit is checked. This overhead is close to four bytes per
7845 object kept. However, pools may actually _save_ memory because of
7846 reduced memory thrashing in your malloc library.
7850 COMMENT: on|off|transparent|truncate|delete
7853 LOC: opt_forwarded_for
7855 If set to "on", Squid will append your client's IP address
7856 in the HTTP requests it forwards. By default it looks like:
7858 X-Forwarded-For: 192.1.2.3
7860 If set to "off", it will appear as
7862 X-Forwarded-For: unknown
7864 If set to "transparent", Squid will not alter the
7865 X-Forwarded-For header in any way.
7867 If set to "delete", Squid will delete the entire
7868 X-Forwarded-For header.
7870 If set to "truncate", Squid will remove all existing
7871 X-Forwarded-For entries, and place the client IP as the sole entry.
7874 NAME: cachemgr_passwd
7875 TYPE: cachemgrpasswd
7877 LOC: Config.passwd_list
7879 Specify passwords for cachemgr operations.
7881 Usage: cachemgr_passwd password action action ...
7883 Some valid actions are (see cache manager menu for a full list):
7923 * Indicates actions which will not be performed without a
7924 valid password, others can be performed if not listed here.
7926 To disable an action, set the password to "disable".
7927 To allow performing an action without a password, set the
7930 Use the keyword "all" to set the same password for all actions.
7933 cachemgr_passwd secret shutdown
7934 cachemgr_passwd lesssssssecret info stats/objects
7935 cachemgr_passwd disable all
7942 LOC: Config.onoff.client_db
7944 If you want to disable collecting per-client statistics,
7945 turn off client_db here.
7948 NAME: refresh_all_ims
7952 LOC: Config.onoff.refresh_all_ims
7954 When you enable this option, squid will always check
7955 the origin server for an update when a client sends an
7956 If-Modified-Since request. Many browsers use IMS
7957 requests when the user requests a reload, and this
7958 ensures those clients receive the latest version.
7960 By default (off), squid may return a Not Modified response
7961 based on the age of the cached version.
7964 NAME: reload_into_ims
7965 IFDEF: USE_HTTP_VIOLATIONS
7969 LOC: Config.onoff.reload_into_ims
7971 When you enable this option, client no-cache or ``reload''
7972 requests will be changed to If-Modified-Since requests.
7973 Doing this VIOLATES the HTTP standard. Enabling this
7974 feature could make you liable for problems which it
7977 see also refresh_pattern for a more selective approach.
7980 NAME: connect_retries
7982 LOC: Config.connect_retries
7985 This sets the maximum number of connection attempts made for each
7986 TCP connection. The connect_retries attempts must all still
7987 complete within the connection timeout period.
7989 The default is not to re-try if the first connection attempt fails.
7990 The (not recommended) maximum is 10 tries.
7992 A warning message will be generated if it is set to a too-high
7993 value and the configured value will be over-ridden.
7995 Note: These re-tries are in addition to forward_max_tries
7996 which limit how many different addresses may be tried to find
8000 NAME: retry_on_error
8002 LOC: Config.retry.onerror
8005 If set to ON Squid will automatically retry requests when
8006 receiving an error response with status 403 (Forbidden),
8007 500 (Internal Error), 501 or 503 (Service not available).
8008 Status 502 and 504 (Gateway errors) are always retried.
8010 This is mainly useful if you are in a complex cache hierarchy to
8011 work around access control errors.
8013 NOTE: This retry will attempt to find another working destination.
8014 Which is different from the server which just failed.
8017 NAME: as_whois_server
8019 LOC: Config.as_whois_server
8020 DEFAULT: whois.ra.net
8022 WHOIS server to query for AS numbers. NOTE: AS numbers are
8023 queried only when Squid starts up, not for every request.
8028 LOC: Config.onoff.offline
8031 Enable this option and Squid will never try to validate cached
8035 NAME: uri_whitespace
8036 TYPE: uri_whitespace
8037 LOC: Config.uri_whitespace
8040 What to do with requests that have whitespace characters in the
8043 strip: The whitespace characters are stripped out of the URL.
8044 This is the behavior recommended by RFC2396.
8045 deny: The request is denied. The user receives an "Invalid
8047 allow: The request is allowed and the URI is not changed. The
8048 whitespace characters remain in the URI. Note the
8049 whitespace is passed to redirector processes if they
8051 encode: The request is allowed and the whitespace characters are
8052 encoded according to RFC1738. This could be considered
8053 a violation of the HTTP/1.1
8054 RFC because proxies are not allowed to rewrite URI's.
8055 chop: The request is allowed and the URI is chopped at the
8056 first whitespace. This might also be considered a
8062 LOC: Config.chroot_dir
8065 Specifies a directory where Squid should do a chroot() while
8066 initializing. This also causes Squid to fully drop root
8067 privileges after initializing. This means, for example, if you
8068 use a HTTP port less than 1024 and try to reconfigure, you may
8069 get an error saying that Squid can not open the port.
8072 NAME: balance_on_multiple_ip
8074 LOC: Config.onoff.balance_on_multiple_ip
8077 Modern IP resolvers in squid sort lookup results by preferred access.
8078 By default squid will use these IP in order and only rotates to
8079 the next listed when the most preffered fails.
8081 Some load balancing servers based on round robin DNS have been
8082 found not to preserve user session state across requests
8083 to different IP addresses.
8085 Enabling this directive Squid rotates IP's per request.
8088 NAME: pipeline_prefetch
8090 LOC: Config.onoff.pipeline_prefetch
8093 To boost the performance of pipelined requests to closer
8094 match that of a non-proxied environment Squid can try to fetch
8095 up to two requests in parallel from a pipeline.
8097 Defaults to off for bandwidth management and access logging
8100 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
8103 NAME: high_response_time_warning
8106 LOC: Config.warnings.high_rptm
8109 If the one-minute median response time exceeds this value,
8110 Squid prints a WARNING with debug level 0 to get the
8111 administrators attention. The value is in milliseconds.
8114 NAME: high_page_fault_warning
8116 LOC: Config.warnings.high_pf
8119 If the one-minute average page fault rate exceeds this
8120 value, Squid prints a WARNING with debug level 0 to get
8121 the administrators attention. The value is in page faults
8125 NAME: high_memory_warning
8127 LOC: Config.warnings.high_memory
8130 If the memory usage (as determined by mallinfo) exceeds
8131 this amount, Squid prints a WARNING with debug level 0 to get
8132 the administrators attention.
8135 NAME: sleep_after_fork
8136 COMMENT: (microseconds)
8138 LOC: Config.sleep_after_fork
8141 When this is set to a non-zero value, the main Squid process
8142 sleeps the specified number of microseconds after a fork()
8143 system call. This sleep may help the situation where your
8144 system reports fork() failures due to lack of (virtual)
8145 memory. Note, however, if you have a lot of child
8146 processes, these sleep delays will add up and your
8147 Squid will not service requests for some amount of time
8148 until all the child processes have been started.
8149 On Windows value less then 1000 (1 milliseconds) are
8153 NAME: windows_ipaddrchangemonitor
8154 IFDEF: _SQUID_WINDOWS_
8158 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
8160 On Windows Squid by default will monitor IP address changes and will
8161 reconfigure itself after any detected event. This is very useful for
8162 proxies connected to internet with dial-up interfaces.
8163 In some cases (a Proxy server acting as VPN gateway is one) it could be
8164 desiderable to disable this behaviour setting this to 'off'.
8165 Note: after changing this, Squid service must be restarted.
8170 IFDEF: USE_SQUID_EUI
8172 LOC: Eui::TheConfig.euiLookup
8174 Whether to lookup the EUI or MAC address of a connected client.
8177 NAME: max_filedescriptors max_filedesc
8180 LOC: Config.max_filedescriptors
8182 The maximum number of filedescriptors supported.
8184 The default "0" means Squid inherits the current ulimit setting.
8186 Note: Changing this requires a restart of Squid. Also
8187 not all comm loops supports large values.
8195 Number of main Squid processes or "workers" to fork and maintain.
8196 0: "no daemon" mode, like running "squid -N ..."
8197 1: "no SMP" mode, start one main Squid process daemon (default)
8198 N: start N main Squid process daemons (i.e., SMP mode)
8200 In SMP mode, each worker does nearly all what a single Squid daemon
8201 does (e.g., listen on http_port and forward HTTP requests).
8204 NAME: cpu_affinity_map
8205 TYPE: CpuAffinityMap
8206 LOC: Config.cpuAffinityMap
8209 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
8211 Sets 1:1 mapping between Squid processes and CPU cores. For example,
8213 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
8215 affects processes 1 through 4 only and places them on the first
8216 four even cores, starting with core #1.
8218 CPU cores are numbered starting from 1. Requires support for
8219 sched_getaffinity(2) and sched_setaffinity(2) system calls.
8221 Multiple cpu_affinity_map options are merged.