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 urlpath_regex [-i] \.gif$ ...
758 # regex matching on URL path [fast]
760 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
762 acl aclname localport 3128 ... # TCP port the client connected to [fast]
763 # NP: for interception mode this is usually '80'
765 acl aclname myportname 3128 ... # http(s)_port name [fast]
767 acl aclname proto HTTP FTP ... # request protocol [fast]
769 acl aclname method GET POST ... # HTTP request method [fast]
771 acl aclname http_status 200 301 500- 400-403 ...
772 # status code in reply [fast]
774 acl aclname browser [-i] regexp ...
775 # pattern match on User-Agent header (see also req_header below) [fast]
777 acl aclname referer_regex [-i] regexp ...
778 # pattern match on Referer header [fast]
779 # Referer is highly unreliable, so use with care
781 acl aclname ident username ...
782 acl aclname ident_regex [-i] pattern ...
783 # string match on ident output [slow]
784 # use REQUIRED to accept any non-null ident.
786 acl aclname proxy_auth [-i] username ...
787 acl aclname proxy_auth_regex [-i] pattern ...
788 # perform http authentication challenge to the client and match against
789 # supplied credentials [slow]
791 # takes a list of allowed usernames.
792 # use REQUIRED to accept any valid username.
794 # Will use proxy authentication in forward-proxy scenarios, and plain
795 # http authenticaiton in reverse-proxy scenarios
797 # NOTE: when a Proxy-Authentication header is sent but it is not
798 # needed during ACL checking the username is NOT logged
801 # NOTE: proxy_auth requires a EXTERNAL authentication program
802 # to check username/password combinations (see
803 # auth_param directive).
805 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
806 # as the browser needs to be configured for using a proxy in order
807 # to respond to proxy authentication.
809 acl aclname snmp_community string ...
810 # A community string to limit access to your SNMP Agent [fast]
813 # acl snmppublic snmp_community public
815 acl aclname maxconn number
816 # This will be matched when the client's IP address has
817 # more than <number> TCP connections established. [fast]
818 # NOTE: This only measures direct TCP links so X-Forwarded-For
819 # indirect clients are not counted.
821 acl aclname max_user_ip [-s] number
822 # This will be matched when the user attempts to log in from more
823 # than <number> different ip addresses. The authenticate_ip_ttl
824 # parameter controls the timeout on the ip entries. [fast]
825 # If -s is specified the limit is strict, denying browsing
826 # from any further IP addresses until the ttl has expired. Without
827 # -s Squid will just annoy the user by "randomly" denying requests.
828 # (the counter is reset each time the limit is reached and a
830 # NOTE: in acceleration mode or where there is mesh of child proxies,
831 # clients may appear to come from multiple addresses if they are
832 # going through proxy farms, so a limit of 1 may cause user problems.
834 acl aclname random probability
835 # Pseudo-randomly match requests. Based on the probability given.
836 # Probability may be written as a decimal (0.333), fraction (1/3)
837 # or ratio of matches:non-matches (3:5).
839 acl aclname req_mime_type [-i] mime-type ...
840 # regex match against the mime type of the request generated
841 # by the client. Can be used to detect file upload or some
842 # types HTTP tunneling requests [fast]
843 # NOTE: This does NOT match the reply. You cannot use this
844 # to match the returned file type.
846 acl aclname req_header header-name [-i] any\.regex\.here
847 # regex match against any of the known request headers. May be
848 # thought of as a superset of "browser", "referer" and "mime-type"
851 acl aclname rep_mime_type [-i] mime-type ...
852 # regex match against the mime type of the reply received by
853 # squid. Can be used to detect file download or some
854 # types HTTP tunneling requests. [fast]
855 # NOTE: This has no effect in http_access rules. It only has
856 # effect in rules that affect the reply data stream such as
859 acl aclname rep_header header-name [-i] any\.regex\.here
860 # regex match against any of the known reply headers. May be
861 # thought of as a superset of "browser", "referer" and "mime-type"
864 acl aclname external class_name [arguments...]
865 # external ACL lookup via a helper class defined by the
866 # external_acl_type directive [slow]
868 acl aclname user_cert attribute values...
869 # match against attributes in a user SSL certificate
870 # attribute is one of DN/C/O/CN/L/ST [fast]
872 acl aclname ca_cert attribute values...
873 # match against attributes a users issuing CA SSL certificate
874 # attribute is one of DN/C/O/CN/L/ST [fast]
876 acl aclname ext_user username ...
877 acl aclname ext_user_regex [-i] pattern ...
878 # string match on username returned by external acl helper [slow]
879 # use REQUIRED to accept any non-null user name.
881 acl aclname tag tagvalue ...
882 # string match on tag returned by external acl helper [slow]
884 acl aclname hier_code codename ...
885 # string match against squid hierarchy code(s); [fast]
886 # e.g., DIRECT, PARENT_HIT, NONE, etc.
888 # NOTE: This has no effect in http_access rules. It only has
889 # effect in rules that affect the reply data stream such as
893 acl aclname ssl_error errorname
894 # match against SSL certificate validation error [fast]
896 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
899 # The following can be used as shortcuts for certificate properties:
900 # [ssl::]certHasExpired: the "not after" field is in the past
901 # [ssl::]certNotYetValid: the "not before" field is in the future
902 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
903 # [ssl::]certSelfSigned: The certificate is self signed.
904 # [ssl::]certDomainMismatch: The certificate CN domain does not
905 # match the name the name of the host we are connecting to.
907 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
908 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
909 # predefined ACLs, just like the 'all' ACL.
911 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
912 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
916 acl macaddress arp 09:00:2b:23:45:67
917 acl myexample dst_as 1241
918 acl password proxy_auth REQUIRED
919 acl fileupload req_mime_type -i ^multipart/form-data$
920 acl javascript rep_mime_type -i ^application/x-javascript$
924 # Recommended minimum configuration:
927 # Example rule allowing access from your local networks.
928 # Adapt to list your (internal) IP networks from where browsing
930 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
931 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
932 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
933 acl localnet src fc00::/7 # RFC 4193 local private network range
934 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
936 acl SSL_ports port 443
937 acl Safe_ports port 80 # http
938 acl Safe_ports port 21 # ftp
939 acl Safe_ports port 443 # https
940 acl Safe_ports port 70 # gopher
941 acl Safe_ports port 210 # wais
942 acl Safe_ports port 1025-65535 # unregistered ports
943 acl Safe_ports port 280 # http-mgmt
944 acl Safe_ports port 488 # gss-http
945 acl Safe_ports port 591 # filemaker
946 acl Safe_ports port 777 # multiling http
947 acl CONNECT method CONNECT
951 NAME: follow_x_forwarded_for
953 IFDEF: FOLLOW_X_FORWARDED_FOR
954 LOC: Config.accessList.followXFF
955 DEFAULT_IF_NONE: deny all
957 Allowing or Denying the X-Forwarded-For header to be followed to
958 find the original source of a request.
960 Requests may pass through a chain of several other proxies
961 before reaching us. The X-Forwarded-For header will contain a
962 comma-separated list of the IP addresses in the chain, with the
963 rightmost address being the most recent.
965 If a request reaches us from a source that is allowed by this
966 configuration item, then we consult the X-Forwarded-For header
967 to see where that host received the request from. If the
968 X-Forwarded-For header contains multiple addresses, we continue
969 backtracking until we reach an address for which we are not allowed
970 to follow the X-Forwarded-For header, or until we reach the first
971 address in the list. For the purpose of ACL used in the
972 follow_x_forwarded_for directive the src ACL type always matches
973 the address we are testing and srcdomain matches its rDNS.
975 The end result of this process is an IP address that we will
976 refer to as the indirect client address. This address may
977 be treated as the client address for access control, ICAP, delay
978 pools and logging, depending on the acl_uses_indirect_client,
979 icap_uses_indirect_client, delay_pool_uses_indirect_client,
980 log_uses_indirect_client and tproxy_uses_indirect_client options.
982 This clause only supports fast acl types.
983 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
985 SECURITY CONSIDERATIONS:
987 Any host for which we follow the X-Forwarded-For header
988 can place incorrect information in the header, and Squid
989 will use the incorrect information as if it were the
990 source address of the request. This may enable remote
991 hosts to bypass any access control restrictions that are
992 based on the client's source addresses.
996 acl localhost src 127.0.0.1
997 acl my_other_proxy srcdomain .proxy.example.com
998 follow_x_forwarded_for allow localhost
999 follow_x_forwarded_for allow my_other_proxy
1002 NAME: acl_uses_indirect_client
1005 IFDEF: FOLLOW_X_FORWARDED_FOR
1007 LOC: Config.onoff.acl_uses_indirect_client
1009 Controls whether the indirect client address
1010 (see follow_x_forwarded_for) is used instead of the
1011 direct client address in acl matching.
1013 NOTE: maxconn ACL considers direct TCP links and indirect
1014 clients will always have zero. So no match.
1017 NAME: delay_pool_uses_indirect_client
1020 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1022 LOC: Config.onoff.delay_pool_uses_indirect_client
1024 Controls whether the indirect client address
1025 (see follow_x_forwarded_for) is used instead of the
1026 direct client address in delay pools.
1029 NAME: log_uses_indirect_client
1032 IFDEF: FOLLOW_X_FORWARDED_FOR
1034 LOC: Config.onoff.log_uses_indirect_client
1036 Controls whether the indirect client address
1037 (see follow_x_forwarded_for) is used instead of the
1038 direct client address in the access log.
1041 NAME: tproxy_uses_indirect_client
1044 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1046 LOC: Config.onoff.tproxy_uses_indirect_client
1048 Controls whether the indirect client address
1049 (see follow_x_forwarded_for) is used instead of the
1050 direct client address when spoofing the outgoing client.
1052 This has no effect on requests arriving in non-tproxy
1055 SECURITY WARNING: Usage of this option is dangerous
1056 and should not be used trivially. Correct configuration
1057 of follow_x_forewarded_for with a limited set of trusted
1058 sources is required to prevent abuse of your proxy.
1063 LOC: Config.accessList.http
1064 DEFAULT_IF_NONE: deny all
1066 Allowing or Denying access based on defined access lists
1068 Access to the HTTP port:
1069 http_access allow|deny [!]aclname ...
1071 NOTE on default values:
1073 If there are no "access" lines present, the default is to deny
1076 If none of the "access" lines cause a match, the default is the
1077 opposite of the last line in the list. If the last line was
1078 deny, the default is allow. Conversely, if the last line
1079 is allow, the default will be deny. For these reasons, it is a
1080 good idea to have an "deny all" entry at the end of your access
1081 lists to avoid potential confusion.
1083 This clause supports both fast and slow acl types.
1084 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1089 # Recommended minimum Access Permission configuration:
1091 # Only allow cachemgr access from localhost
1092 http_access allow localhost manager
1093 http_access deny manager
1095 # Deny requests to certain unsafe ports
1096 http_access deny !Safe_ports
1098 # Deny CONNECT to other than secure SSL ports
1099 http_access deny CONNECT !SSL_ports
1101 # We strongly recommend the following be uncommented to protect innocent
1102 # web applications running on the proxy server who think the only
1103 # one who can access services on "localhost" is a local user
1104 #http_access deny to_localhost
1107 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1110 # Example rule allowing access from your local networks.
1111 # Adapt localnet in the ACL section to list your (internal) IP networks
1112 # from where browsing should be allowed
1113 http_access allow localnet
1114 http_access allow localhost
1116 # And finally deny all other access to this proxy
1117 http_access deny all
1121 NAME: adapted_http_access http_access2
1123 LOC: Config.accessList.adapted_http
1126 Allowing or Denying access based on defined access lists
1128 Essentially identical to http_access, but runs after redirectors
1129 and ICAP/eCAP adaptation. Allowing access control based on their
1132 If not set then only http_access is used.
1135 NAME: http_reply_access
1137 LOC: Config.accessList.reply
1140 Allow replies to client requests. This is complementary to http_access.
1142 http_reply_access allow|deny [!] aclname ...
1144 NOTE: if there are no access lines present, the default is to allow
1147 If none of the access lines cause a match the opposite of the
1148 last line will apply. Thus it is good practice to end the rules
1149 with an "allow all" or "deny all" entry.
1151 This clause supports both fast and slow acl types.
1152 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1157 LOC: Config.accessList.icp
1158 DEFAULT_IF_NONE: deny all
1160 Allowing or Denying access to the ICP port based on defined
1163 icp_access allow|deny [!]aclname ...
1165 See http_access for details
1167 This clause only supports fast acl types.
1168 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1170 # Allow ICP queries from local networks only
1171 #icp_access allow localnet
1172 #icp_access deny all
1178 LOC: Config.accessList.htcp
1179 DEFAULT_IF_NONE: deny all
1181 Allowing or Denying access to the HTCP port based on defined
1184 htcp_access allow|deny [!]aclname ...
1186 See http_access for details
1188 NOTE: The default if no htcp_access lines are present is to
1189 deny all traffic. This default may cause problems with peers
1190 using the htcp option.
1192 This clause only supports fast acl types.
1193 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1195 # Allow HTCP queries from local networks only
1196 #htcp_access allow localnet
1197 #htcp_access deny all
1200 NAME: htcp_clr_access
1203 LOC: Config.accessList.htcp_clr
1204 DEFAULT_IF_NONE: deny all
1206 Allowing or Denying access to purge content using HTCP based
1207 on defined access lists
1209 htcp_clr_access allow|deny [!]aclname ...
1211 See http_access for details
1213 This clause only supports fast acl types.
1214 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1216 # Allow HTCP CLR requests from trusted peers
1217 acl htcp_clr_peer src 172.16.1.2
1218 htcp_clr_access allow htcp_clr_peer
1223 LOC: Config.accessList.miss
1226 Determins whether network access is permitted when satisfying a request.
1229 to force your neighbors to use you as a sibling instead of
1232 acl localclients src 172.16.0.0/16
1233 miss_access allow localclients
1234 miss_access deny !localclients
1236 This means only your local clients are allowed to fetch relayed/MISS
1237 replies from the network and all other clients can only fetch cached
1241 The default for this setting allows all clients who passed the
1242 http_access rules to relay via this proxy.
1244 This clause only supports fast acl types.
1245 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1248 NAME: ident_lookup_access
1251 DEFAULT_IF_NONE: deny all
1252 LOC: Ident::TheConfig.identLookup
1254 A list of ACL elements which, if matched, cause an ident
1255 (RFC 931) lookup to be performed for this request. For
1256 example, you might choose to always perform ident lookups
1257 for your main multi-user Unix boxes, but not for your Macs
1258 and PCs. By default, ident lookups are not performed for
1261 To enable ident lookups for specific client addresses, you
1262 can follow this example:
1264 acl ident_aware_hosts src 198.168.1.0/24
1265 ident_lookup_access allow ident_aware_hosts
1266 ident_lookup_access deny all
1268 Only src type ACL checks are fully supported. A srcdomain
1269 ACL might work at times, but it will not always provide
1272 This clause only supports fast acl types.
1273 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1276 NAME: reply_body_max_size
1277 COMMENT: size [acl acl...]
1280 LOC: Config.ReplyBodySize
1282 This option specifies the maximum size of a reply body. It can be
1283 used to prevent users from downloading very large files, such as
1284 MP3's and movies. When the reply headers are received, the
1285 reply_body_max_size lines are processed, and the first line where
1286 all (if any) listed ACLs are true is used as the maximum body size
1289 This size is checked twice. First when we get the reply headers,
1290 we check the content-length value. If the content length value exists
1291 and is larger than the allowed size, the request is denied and the
1292 user receives an error message that says "the request or reply
1293 is too large." If there is no content-length, and the reply
1294 size exceeds this limit, the client's connection is just closed
1295 and they will receive a partial reply.
1297 WARNING: downstream caches probably can not detect a partial reply
1298 if there is no content-length header, so they will cache
1299 partial responses and give them out as hits. You should NOT
1300 use this option if you have downstream caches.
1302 WARNING: A maximum size smaller than the size of squid's error messages
1303 will cause an infinite loop and crash squid. Ensure that the smallest
1304 non-zero value you use is greater that the maximum header size plus
1305 the size of your largest error page.
1307 If you set this parameter none (the default), there will be
1310 Configuration Format is:
1311 reply_body_max_size SIZE UNITS [acl ...]
1313 reply_body_max_size 10 MB
1319 -----------------------------------------------------------------------------
1322 NAME: http_port ascii_port
1325 LOC: Config.Sockaddr.http
1327 Usage: port [mode] [options]
1328 hostname:port [mode] [options]
1329 1.2.3.4:port [mode] [options]
1331 The socket addresses where Squid will listen for HTTP client
1332 requests. You may specify multiple socket addresses.
1333 There are three forms: port alone, hostname with port, and
1334 IP address with port. If you specify a hostname or IP
1335 address, Squid binds the socket to that specific
1336 address. Most likely, you do not need to bind to a specific
1337 address, so you can use the port number alone.
1339 If you are running Squid in accelerator mode, you
1340 probably want to listen on port 80 also, or instead.
1342 The -a command line option may be used to specify additional
1343 port(s) where Squid listens for proxy request. Such ports will
1344 be plain proxy ports with no options.
1346 You may specify multiple socket addresses on multiple lines.
1350 intercept Support for IP-Layer interception of
1351 outgoing requests without browser settings.
1352 NP: disables authentication and IPv6 on the port.
1354 tproxy Support Linux TPROXY for spoofing outgoing
1355 connections using the client IP address.
1356 NP: disables authentication and maybe IPv6 on the port.
1358 accel Accelerator / reverse proxy mode
1360 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1361 establish secure connection with the client and with
1362 the server, decrypt HTTPS messages as they pass through
1363 Squid, and treat them as unencrypted HTTP messages,
1364 becoming the man-in-the-middle.
1366 The ssl_bump option is required to fully enable
1367 bumping of CONNECT requests.
1369 Omitting the mode flag causes default forward proxy mode to be used.
1372 Accelerator Mode Options:
1374 defaultsite=domainname
1375 What to use for the Host: header if it is not present
1376 in a request. Determines what site (not origin server)
1377 accelerators should consider the default.
1379 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1381 protocol= Protocol to reconstruct accelerated requests with.
1382 Defaults to http for http_port and https for
1385 vport Virtual host port support. Using the http_port number
1386 instead of the port passed on Host: headers.
1388 vport=NN Virtual host port support. Using the specified port
1389 number instead of the port passed on Host: headers.
1392 Act as if this Squid is the origin server.
1393 This currently means generate new Date: and Expires:
1394 headers on HIT instead of adding Age:.
1396 ignore-cc Ignore request Cache-Control headers.
1398 WARNING: This option violates HTTP specifications if
1399 used in non-accelerator setups.
1401 allow-direct Allow direct forwarding in accelerator mode. Normally
1402 accelerated requests are denied direct forwarding as if
1403 never_direct was used.
1405 WARNING: this option opens accelerator mode to security
1406 vulnerabilities usually only affecting in interception
1407 mode. Make sure to protect forwarding with suitable
1408 http_access rules when using this.
1411 SSL Bump Mode Options:
1412 In addition to these options ssl-bump requires TLS/SSL options.
1414 generate-host-certificates[=<on|off>]
1415 Dynamically create SSL server certificates for the
1416 destination hosts of bumped CONNECT requests.When
1417 enabled, the cert and key options are used to sign
1418 generated certificates. Otherwise generated
1419 certificate will be selfsigned.
1420 If there is a CA certificate lifetime of the generated
1421 certificate equals lifetime of the CA certificate. If
1422 generated certificate is selfsigned lifetime is three
1424 This option is enabled by default when ssl-bump is used.
1425 See the ssl-bump option above for more information.
1427 dynamic_cert_mem_cache_size=SIZE
1428 Approximate total RAM size spent on cached generated
1429 certificates. If set to zero, caching is disabled. The
1430 default value is 4MB.
1434 cert= Path to SSL certificate (PEM format).
1436 key= Path to SSL private key file (PEM format)
1437 if not specified, the certificate file is
1438 assumed to be a combined certificate and
1441 version= The version of SSL/TLS supported
1442 1 automatic (default)
1449 cipher= Colon separated list of supported ciphers.
1450 NOTE: some ciphers such as EDH ciphers depend on
1451 additional settings. If those settings are
1452 omitted the ciphers may be silently ignored
1453 by the OpenSSL library.
1455 options= Various SSL implementation options. The most important
1457 NO_SSLv2 Disallow the use of SSLv2
1458 NO_SSLv3 Disallow the use of SSLv3
1459 NO_TLSv1 Disallow the use of TLSv1.0
1460 NO_TLSv1_1 Disallow the use of TLSv1.1
1461 NO_TLSv1_2 Disallow the use of TLSv1.2
1462 SINGLE_DH_USE Always create a new key when using
1463 temporary/ephemeral DH key exchanges
1464 ALL Enable various bug workarounds
1465 suggested as "harmless" by OpenSSL
1466 Be warned that this reduces SSL/TLS
1467 strength to some attacks.
1468 See OpenSSL SSL_CTX_set_options documentation for a
1469 complete list of options.
1471 clientca= File containing the list of CAs to use when
1472 requesting a client certificate.
1474 cafile= File containing additional CA certificates to
1475 use when verifying client certificates. If unset
1476 clientca will be used.
1478 capath= Directory containing additional CA certificates
1479 and CRL lists to use when verifying client certificates.
1481 crlfile= File of additional CRL lists to use when verifying
1482 the client certificate, in addition to CRLs stored in
1483 the capath. Implies VERIFY_CRL flag below.
1485 dhparams= File containing DH parameters for temporary/ephemeral
1486 DH key exchanges. See OpenSSL documentation for details
1487 on how to create this file.
1488 WARNING: EDH ciphers will be silently disabled if this
1491 sslflags= Various flags modifying the use of SSL:
1493 Don't request client certificates
1494 immediately, but wait until acl processing
1495 requires a certificate (not yet implemented).
1497 Don't use the default CA lists built in
1500 Don't allow for session reuse. Each connection
1501 will result in a new SSL session.
1503 Verify CRL lists when accepting client
1506 Verify CRL lists for all certificates in the
1507 client certificate chain.
1509 sslcontext= SSL session ID context identifier.
1513 connection-auth[=on|off]
1514 use connection-auth=off to tell Squid to prevent
1515 forwarding Microsoft connection oriented authentication
1516 (NTLM, Negotiate and Kerberos)
1518 disable-pmtu-discovery=
1519 Control Path-MTU discovery usage:
1520 off lets OS decide on what to do (default).
1521 transparent disable PMTU discovery when transparent
1523 always disable always PMTU discovery.
1525 In many setups of transparently intercepting proxies
1526 Path-MTU discovery can not work on traffic towards the
1527 clients. This is the case when the intercepting device
1528 does not fully track connections and fails to forward
1529 ICMP must fragment messages to the cache server. If you
1530 have such setup and experience that certain clients
1531 sporadically hang or never complete requests set
1532 disable-pmtu-discovery option to 'transparent'.
1534 name= Specifies a internal name for the port. Defaults to
1535 the port specification (port or addr:port)
1537 tcpkeepalive[=idle,interval,timeout]
1538 Enable TCP keepalive probes of idle connections.
1539 In seconds; idle is the initial time before TCP starts
1540 probing the connection, interval how often to probe, and
1541 timeout the time before giving up.
1543 If you run Squid on a dual-homed machine with an internal
1544 and an external interface we recommend you to specify the
1545 internal address:port in http_port. This way Squid will only be
1546 visible on the internal address.
1550 # Squid normally listens to port 3128
1551 http_port @DEFAULT_HTTP_PORT@
1559 LOC: Config.Sockaddr.https
1561 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1563 The socket address where Squid will listen for client requests made
1564 over TLS or SSL connections. Commonly referred to as HTTPS.
1566 This is most useful for situations where you are running squid in
1567 accelerator mode and you want to do the SSL work at the accelerator level.
1569 You may specify multiple socket addresses on multiple lines,
1570 each with their own SSL certificate and/or options.
1574 accel Accelerator / reverse proxy mode
1576 intercept Support for IP-Layer interception of
1577 outgoing requests without browser settings.
1578 NP: disables authentication and IPv6 on the port.
1580 tproxy Support Linux TPROXY for spoofing outgoing
1581 connections using the client IP address.
1582 NP: disables authentication and maybe IPv6 on the port.
1584 ssl-bump For each intercepted connection allowed by ssl_bump
1585 ACLs, establish a secure connection with the client and with
1586 the server, decrypt HTTPS messages as they pass through
1587 Squid, and treat them as unencrypted HTTP messages,
1588 becoming the man-in-the-middle.
1590 An "ssl_bump server-first" match is required to
1591 fully enable bumping of intercepted SSL connections.
1593 Requires tproxy or intercept.
1595 Omitting the mode flag causes default forward proxy mode to be used.
1598 See http_port for a list of generic options
1603 cert= Path to SSL certificate (PEM format).
1605 key= Path to SSL private key file (PEM format)
1606 if not specified, the certificate file is
1607 assumed to be a combined certificate and
1610 version= The version of SSL/TLS supported
1611 1 automatic (default)
1616 cipher= Colon separated list of supported ciphers.
1618 options= Various SSL engine options. The most important
1620 NO_SSLv2 Disallow the use of SSLv2
1621 NO_SSLv3 Disallow the use of SSLv3
1622 NO_TLSv1 Disallow the use of TLSv1
1623 SINGLE_DH_USE Always create a new key when using
1624 temporary/ephemeral DH key exchanges
1625 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1626 documentation for a complete list of options.
1628 clientca= File containing the list of CAs to use when
1629 requesting a client certificate.
1631 cafile= File containing additional CA certificates to
1632 use when verifying client certificates. If unset
1633 clientca will be used.
1635 capath= Directory containing additional CA certificates
1636 and CRL lists to use when verifying client certificates.
1638 crlfile= File of additional CRL lists to use when verifying
1639 the client certificate, in addition to CRLs stored in
1640 the capath. Implies VERIFY_CRL flag below.
1642 dhparams= File containing DH parameters for temporary/ephemeral
1645 sslflags= Various flags modifying the use of SSL:
1647 Don't request client certificates
1648 immediately, but wait until acl processing
1649 requires a certificate (not yet implemented).
1651 Don't use the default CA lists built in
1654 Don't allow for session reuse. Each connection
1655 will result in a new SSL session.
1657 Verify CRL lists when accepting client
1660 Verify CRL lists for all certificates in the
1661 client certificate chain.
1663 sslcontext= SSL session ID context identifier.
1665 generate-host-certificates[=<on|off>]
1666 Dynamically create SSL server certificates for the
1667 destination hosts of bumped SSL requests.When
1668 enabled, the cert and key options are used to sign
1669 generated certificates. Otherwise generated
1670 certificate will be selfsigned.
1671 If there is CA certificate life time of generated
1672 certificate equals lifetime of CA certificate. If
1673 generated certificate is selfsigned lifetime is three
1675 This option is enabled by default when SslBump is used.
1676 See the sslBump option above for more information.
1678 dynamic_cert_mem_cache_size=SIZE
1679 Approximate total RAM size spent on cached generated
1680 certificates. If set to zero, caching is disabled. The
1681 default value is 4MB.
1683 See http_port for a list of available options.
1686 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1689 LOC: Ip::Qos::TheConfig.tosToServer
1691 Allows you to select a TOS/Diffserv value for packets outgoing
1692 on the server side, based on an ACL.
1694 tcp_outgoing_tos ds-field [!]aclname ...
1696 Example where normal_service_net uses the TOS value 0x00
1697 and good_service_net uses 0x20
1699 acl normal_service_net src 10.0.0.0/24
1700 acl good_service_net src 10.0.1.0/24
1701 tcp_outgoing_tos 0x00 normal_service_net
1702 tcp_outgoing_tos 0x20 good_service_net
1704 TOS/DSCP values really only have local significance - so you should
1705 know what you're specifying. For more information, see RFC2474,
1706 RFC2475, and RFC3260.
1708 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1709 "default" to use whatever default your host has. Note that in
1710 practice often only multiples of 4 is usable as the two rightmost bits
1711 have been redefined for use by ECN (RFC 3168 section 23.1).
1713 Processing proceeds in the order specified, and stops at first fully
1717 NAME: clientside_tos
1720 LOC: Ip::Qos::TheConfig.tosToClient
1722 Allows you to select a TOS/Diffserv value for packets being transmitted
1723 on the client-side, based on an ACL.
1725 clientside_tos ds-field [!]aclname ...
1727 Example where normal_service_net uses the TOS value 0x00
1728 and good_service_net uses 0x20
1730 acl normal_service_net src 10.0.0.0/24
1731 acl good_service_net src 10.0.1.0/24
1732 clientside_tos 0x00 normal_service_net
1733 clientside_tos 0x20 good_service_net
1735 Note: This feature is incompatible with qos_flows. Any TOS values set here
1736 will be overwritten by TOS values in qos_flows.
1739 NAME: tcp_outgoing_mark
1741 IFDEF: SO_MARK&&USE_LIBCAP
1743 LOC: Ip::Qos::TheConfig.nfmarkToServer
1745 Allows you to apply a Netfilter mark value to outgoing packets
1746 on the server side, based on an ACL.
1748 tcp_outgoing_mark mark-value [!]aclname ...
1750 Example where normal_service_net uses the mark value 0x00
1751 and good_service_net uses 0x20
1753 acl normal_service_net src 10.0.0.0/24
1754 acl good_service_net src 10.0.1.0/24
1755 tcp_outgoing_mark 0x00 normal_service_net
1756 tcp_outgoing_mark 0x20 good_service_net
1759 NAME: clientside_mark
1761 IFDEF: SO_MARK&&USE_LIBCAP
1763 LOC: Ip::Qos::TheConfig.nfmarkToClient
1765 Allows you to apply a Netfilter mark value to packets being transmitted
1766 on the client-side, based on an ACL.
1768 clientside_mark mark-value [!]aclname ...
1770 Example where normal_service_net uses the mark value 0x00
1771 and good_service_net uses 0x20
1773 acl normal_service_net src 10.0.0.0/24
1774 acl good_service_net src 10.0.1.0/24
1775 clientside_mark 0x00 normal_service_net
1776 clientside_mark 0x20 good_service_net
1778 Note: This feature is incompatible with qos_flows. Any mark values set here
1779 will be overwritten by mark values in qos_flows.
1786 LOC: Ip::Qos::TheConfig
1788 Allows you to select a TOS/DSCP value to mark outgoing
1789 connections with, based on where the reply was sourced. For
1790 platforms using netfilter, allows you to set a netfilter mark
1791 value instead of, or in addition to, a TOS value.
1793 TOS values really only have local significance - so you should
1794 know what you're specifying. For more information, see RFC2474,
1795 RFC2475, and RFC3260.
1797 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1798 in practice often only multiples of 4 is usable as the two rightmost bits
1799 have been redefined for use by ECN (RFC 3168 section 23.1).
1801 Mark values can be any unsigned 32-bit integer value.
1803 This setting is configured by setting the following values:
1805 tos|mark Whether to set TOS or netfilter mark values
1807 local-hit=0xFF Value to mark local cache hits.
1809 sibling-hit=0xFF Value to mark hits from sibling peers.
1811 parent-hit=0xFF Value to mark hits from parent peers.
1813 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
1814 over the preserve-miss feature (see below), unless
1815 mask is specified, in which case only the bits
1816 specified in the mask are written.
1818 The TOS variant of the following features are only possible on Linux
1819 and require your kernel to be patched with the TOS preserving ZPH
1820 patch, available from http://zph.bratcheda.org
1821 No patch is needed to preserve the netfilter mark, which will work
1822 with all variants of netfilter.
1824 disable-preserve-miss
1825 This option disables the preservation of the TOS or netfilter
1826 mark. By default, the existing TOS or netfilter mark value of
1827 the response coming from the remote server will be retained
1828 and masked with miss-mark.
1829 NOTE: in the case of a netfilter mark, the mark must be set on
1830 the connection (using the CONNMARK target) not on the packet
1834 Allows you to mask certain bits in the TOS or mark value
1835 received from the remote server, before copying the value to
1836 the TOS sent towards clients.
1837 Default for tos: 0xFF (TOS from server is not changed).
1838 Default for mark: 0xFFFFFFFF (mark from server is not changed).
1840 All of these features require the --enable-zph-qos compilation flag
1841 (enabled by default). Netfilter marking also requires the
1842 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
1843 libcap 2.09+ (--with-libcap).
1847 NAME: tcp_outgoing_address
1850 LOC: Config.accessList.outgoing_address
1852 Allows you to map requests to different outgoing IP addresses
1853 based on the username or source address of the user making
1856 tcp_outgoing_address ipaddr [[!]aclname] ...
1859 Forwarding clients with dedicated IPs for certain subnets.
1861 acl normal_service_net src 10.0.0.0/24
1862 acl good_service_net src 10.0.2.0/24
1864 tcp_outgoing_address 2001:db8::c001 good_service_net
1865 tcp_outgoing_address 10.1.0.2 good_service_net
1867 tcp_outgoing_address 2001:db8::beef normal_service_net
1868 tcp_outgoing_address 10.1.0.1 normal_service_net
1870 tcp_outgoing_address 2001:db8::1
1871 tcp_outgoing_address 10.1.0.3
1873 Processing proceeds in the order specified, and stops at first fully
1876 Squid will add an implicit IP version test to each line.
1877 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
1878 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
1881 NOTE: The use of this directive using client dependent ACLs is
1882 incompatible with the use of server side persistent connections. To
1883 ensure correct results it is best to set server_persistent_connections
1884 to off when using this directive in such configurations.
1886 NOTE: The use of this directive to set a local IP on outgoing TCP links
1887 is incompatible with using TPROXY to set client IP out outbound TCP links.
1888 When needing to contact peers use the no-tproxy cache_peer option and the
1889 client_dst_passthru directive re-enable normal forwarding such as this.
1893 NAME: host_verify_strict
1896 LOC: Config.onoff.hostStrictVerify
1898 Regardless of this option setting, when dealing with intercepted
1899 traffic, Squid always verifies that the destination IP address matches
1900 the Host header domain or IP (called 'authority form URL').
1902 This enforcement is performed to satisfy a MUST-level requirement in
1903 RFC 2616 section 14.23: "The Host field value MUST represent the naming
1904 authority of the origin server or gateway given by the original URL".
1907 Squid always responds with an HTTP 409 (Conflict) error
1908 page and logs a security warning if there is no match.
1910 Squid verifies that the destination IP address matches
1911 the Host header for forward-proxy and reverse-proxy traffic
1912 as well. For those traffic types, Squid also enables the
1913 following checks, comparing the corresponding Host header
1914 and Request-URI components:
1916 * The host names (domain or IP) must be identical,
1917 but valueless or missing Host header disables all checks.
1918 For the two host names to match, both must be either IP
1921 * Port numbers must be identical, but if a port is missing
1922 the scheme-default port is assumed.
1925 When set to OFF (the default):
1926 Squid allows suspicious requests to continue but logs a
1927 security warning and blocks caching of the response.
1929 * Forward-proxy traffic is not checked at all.
1931 * Reverse-proxy traffic is not checked at all.
1933 * Intercepted traffic which passes verification is handled
1934 according to client_dst_passthru.
1936 * Intercepted requests which fail verification are sent
1937 to the client original destination instead of DIRECT.
1938 This overrides 'client_dst_passthru off'.
1940 For now suspicious intercepted CONNECT requests are always
1941 responded to with an HTTP 409 (Conflict) error page.
1946 As described in CVE-2009-0801 when the Host: header alone is used
1947 to determine the destination of a request it becomes trivial for
1948 malicious scripts on remote websites to bypass browser same-origin
1949 security policy and sandboxing protections.
1951 The cause of this is that such applets are allowed to perform their
1952 own HTTP stack, in which case the same-origin policy of the browser
1953 sandbox only verifies that the applet tries to contact the same IP
1954 as from where it was loaded at the IP level. The Host: header may
1955 be different from the connected IP and approved origin.
1959 NAME: client_dst_passthru
1962 LOC: Config.onoff.client_dst_passthru
1964 With NAT or TPROXY intercepted traffic Squid may pass the request
1965 directly to the original client destination IP or seek a faster
1966 source using the HTTP Host header.
1968 Using Host to locate alternative servers can provide faster
1969 connectivity with a range of failure recovery options.
1970 But can also lead to connectivity trouble when the client and
1971 server are attempting stateful interactions unaware of the proxy.
1973 This option (on by default) prevents alternative DNS entries being
1974 located to send intercepted traffic DIRECT to an origin server.
1975 The clients original destination IP and port will be used instead.
1977 Regardless of this option setting, when dealing with intercepted
1978 traffic Squid will verify the Host: header and any traffic which
1979 fails Host verification will be treated as if this option were ON.
1981 see host_verify_strict for details on the verification process.
1986 -----------------------------------------------------------------------------
1989 NAME: ssl_unclean_shutdown
1993 LOC: Config.SSL.unclean_shutdown
1995 Some browsers (especially MSIE) bugs out on SSL shutdown
2002 LOC: Config.SSL.ssl_engine
2005 The OpenSSL engine to use. You will need to set this if you
2006 would like to use hardware SSL acceleration for example.
2009 NAME: sslproxy_client_certificate
2012 LOC: Config.ssl_client.cert
2015 Client SSL Certificate to use when proxying https:// URLs
2018 NAME: sslproxy_client_key
2021 LOC: Config.ssl_client.key
2024 Client SSL Key to use when proxying https:// URLs
2027 NAME: sslproxy_version
2030 LOC: Config.ssl_client.version
2033 SSL version level to use when proxying https:// URLs
2035 The versions of SSL/TLS supported:
2037 1 automatic (default)
2045 NAME: sslproxy_options
2048 LOC: Config.ssl_client.options
2051 SSL implementation options to use when proxying https:// URLs
2053 The most important being:
2055 NO_SSLv2 Disallow the use of SSLv2
2056 NO_SSLv3 Disallow the use of SSLv3
2057 NO_TLSv1 Disallow the use of TLSv1.0
2058 NO_TLSv1_1 Disallow the use of TLSv1.1
2059 NO_TLSv1_2 Disallow the use of TLSv1.2
2061 Always create a new key when using temporary/ephemeral
2064 Disable use of RFC5077 session tickets. Some servers
2065 may have problems understanding the TLS extension due
2066 to ambiguous specification in RFC4507.
2067 ALL Enable various bug workarounds suggested as "harmless"
2068 by OpenSSL. Be warned that this may reduce SSL/TLS
2069 strength to some attacks.
2071 See the OpenSSL SSL_CTX_set_options documentation for a
2072 complete list of possible options.
2075 NAME: sslproxy_cipher
2078 LOC: Config.ssl_client.cipher
2081 SSL cipher list to use when proxying https:// URLs
2083 Colon separated list of supported ciphers.
2086 NAME: sslproxy_cafile
2089 LOC: Config.ssl_client.cafile
2092 file containing CA certificates to use when verifying server
2093 certificates while proxying https:// URLs
2096 NAME: sslproxy_capath
2099 LOC: Config.ssl_client.capath
2102 directory containing CA certificates to use when verifying
2103 server certificates while proxying https:// URLs
2108 TYPE: sslproxy_ssl_bump
2109 LOC: Config.accessList.ssl_bump
2112 This option is consulted when a CONNECT request is received on
2113 an http_port (or a new connection is intercepted at an
2114 https_port), provided that port was configured with an ssl-bump
2115 flag. The subsequent data on the connection is either treated as
2116 HTTPS and decrypted OR tunneled at TCP level without decryption,
2117 depending on the first bumping "mode" which ACLs match.
2119 ssl_bump <mode> [!]acl ...
2121 The following bumping modes are supported:
2124 Allow bumping of the connection. Establish a secure connection
2125 with the client first, then connect to the server. This old mode
2126 does not allow Squid to mimic server SSL certificate and does
2127 not work with intercepted SSL connections.
2130 Allow bumping of the connection. Establish a secure connection
2131 with the server first, then establish a secure connection with
2132 the client, using a mimicked server certificate. Works with both
2133 CONNECT requests and intercepted SSL connections.
2136 Become a TCP tunnel without decoding the connection.
2137 Works with both CONNECT requests and intercepted SSL
2138 connections. This is the default behavior when no
2139 ssl_bump option is given or no ssl_bump ACLs match.
2141 By default, no connections are bumped.
2143 The first matching ssl_bump option wins. If no ACLs match, the
2144 connection is not bumped. Unlike most allow/deny ACL lists, ssl_bump
2145 does not have an implicit "negate the last given option" rule. You
2146 must make that rule explicit if you convert old ssl_bump allow/deny
2147 rules that rely on such an implicit rule.
2149 This clause supports both fast and slow acl types.
2150 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2152 See also: http_port ssl-bump, https_port ssl-bump
2155 # Example: Bump all requests except those originating from
2156 # localhost and those going to example.com.
2158 acl broken_sites dstdomain .example.com
2159 ssl_bump none localhost
2160 ssl_bump none broken_sites
2161 ssl_bump server-first all
2164 NAME: sslproxy_flags
2167 LOC: Config.ssl_client.flags
2170 Various flags modifying the use of SSL while proxying https:// URLs:
2171 DONT_VERIFY_PEER Accept certificates that fail verification.
2172 For refined control, see sslproxy_cert_error.
2173 NO_DEFAULT_CA Don't use the default CA list built in
2177 NAME: sslproxy_cert_error
2180 LOC: Config.ssl_client.cert_error
2183 Use this ACL to bypass server certificate validation errors.
2185 For example, the following lines will bypass all validation errors
2186 when talking to servers for example.com. All other
2187 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2189 acl BrokenButTrustedServers dstdomain example.com
2190 sslproxy_cert_error allow BrokenButTrustedServers
2191 sslproxy_cert_error deny all
2193 This clause only supports fast acl types.
2194 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2195 Using slow acl types may result in server crashes
2197 Without this option, all server certificate validation errors
2198 terminate the transaction. Bypassing validation errors is dangerous
2199 because an error usually implies that the server cannot be trusted and
2200 the connection may be insecure.
2202 See also: sslproxy_flags and DONT_VERIFY_PEER.
2204 Default setting: sslproxy_cert_error deny all
2207 NAME: sslproxy_cert_sign
2210 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2211 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2212 POSTSCRIPTUM: signTrusted all
2213 TYPE: sslproxy_cert_sign
2214 LOC: Config.ssl_client.cert_sign
2217 sslproxy_cert_sign <signing algorithm> acl ...
2219 The following certificate signing algorithms are supported:
2221 Sign using the configured CA certificate which is usually
2222 placed in and trusted by end-user browsers. This is the
2223 default for trusted origin server certificates.
2225 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2226 This is the default for untrusted origin server certificates
2227 that are not self-signed (see ssl::certUntrusted).
2229 Sign using a self-signed certificate with the right CN to
2230 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2231 browser. This is the default for self-signed origin server
2232 certificates (see ssl::certSelfSigned).
2234 This clause only supports fast acl types.
2236 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2237 signing algorithm to generate the certificate and ignores all
2238 subsequent sslproxy_cert_sign options (the first match wins). If no
2239 acl(s) match, the default signing algorithm is determined by errors
2240 detected when obtaining and validating the origin server certificate.
2242 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2243 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2244 CONNECT request that carries a domain name. In all other cases (CONNECT
2245 to an IP address or an intercepted SSL connection), Squid cannot detect
2246 the domain mismatch at certificate generation time when
2247 bump-server-first is used.
2250 NAME: sslproxy_cert_adapt
2253 TYPE: sslproxy_cert_adapt
2254 LOC: Config.ssl_client.cert_adapt
2257 sslproxy_cert_adapt <adaptation algorithm> acl ...
2259 The following certificate adaptation algorithms are supported:
2261 Sets the "Not After" property to the "Not After" property of
2262 the CA certificate used to sign generated certificates.
2264 Sets the "Not Before" property to the "Not Before" property of
2265 the CA certificate used to sign generated certificates.
2266 setCommonName or setCommonName{CN}
2267 Sets Subject.CN property to the host name specified as a
2268 CN parameter or, if no explicit CN parameter was specified,
2269 extracted from the CONNECT request. It is a misconfiguration
2270 to use setCommonName without an explicit parameter for
2271 intercepted or tproxied SSL connections.
2273 This clause only supports fast acl types.
2275 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2276 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2277 corresponding adaptation algorithm to generate the certificate and
2278 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2279 group (i.e., the first match wins within each algorithm group). If no
2280 acl(s) match, the default mimicking action takes place.
2282 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2283 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2284 CONNECT request that carries a domain name. In all other cases (CONNECT
2285 to an IP address or an intercepted SSL connection), Squid cannot detect
2286 the domain mismatch at certificate generation time when
2287 bump-server-first is used.
2290 NAME: sslpassword_program
2293 LOC: Config.Program.ssl_password
2296 Specify a program used for entering SSL key passphrases
2297 when using encrypted SSL certificate keys. If not specified
2298 keys must either be unencrypted, or Squid started with the -N
2299 option to allow it to query interactively for the passphrase.
2301 The key file name is given as argument to the program allowing
2302 selection of the right password if you have multiple encrypted
2307 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2308 -----------------------------------------------------------------------------
2311 NAME: sslcrtd_program
2314 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2315 LOC: Ssl::TheConfig.ssl_crtd
2317 Specify the location and options of the executable for ssl_crtd process.
2318 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2319 For more information use:
2320 @DEFAULT_SSL_CRTD@ -h
2323 NAME: sslcrtd_children
2324 TYPE: HelperChildConfig
2326 DEFAULT: 32 startup=5 idle=1
2327 LOC: Ssl::TheConfig.ssl_crtdChildren
2329 The maximum number of processes spawn to service ssl server.
2330 The maximum this may be safely set to is 32.
2332 The startup= and idle= options allow some measure of skew in your
2337 Sets the minimum number of processes to spawn when Squid
2338 starts or reconfigures. When set to zero the first request will
2339 cause spawning of the first child process to handle it.
2341 Starting too few children temporary slows Squid under load while it
2342 tries to spawn enough additional processes to cope with traffic.
2346 Sets a minimum of how many processes Squid is to try and keep available
2347 at all times. When traffic begins to rise above what the existing
2348 processes can handle this many more will be spawned up to the maximum
2349 configured. A minimum setting of 1 is required.
2351 You must have at least one ssl_crtd process.
2355 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2356 -----------------------------------------------------------------------------
2364 To specify other caches in a hierarchy, use the format:
2366 cache_peer hostname type http-port icp-port [options]
2371 # hostname type port port options
2372 # -------------------- -------- ----- ----- -----------
2373 cache_peer parent.foo.net parent 3128 3130 default
2374 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2375 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2376 cache_peer example.com parent 80 0 default
2377 cache_peer cdn.example.com sibling 3128 0
2379 type: either 'parent', 'sibling', or 'multicast'.
2381 proxy-port: The port number where the peer accept HTTP requests.
2382 For other Squid proxies this is usually 3128
2383 For web servers this is usually 80
2385 icp-port: Used for querying neighbor caches about objects.
2386 Set to 0 if the peer does not support ICP or HTCP.
2387 See ICP and HTCP options below for additional details.
2390 ==== ICP OPTIONS ====
2392 You MUST also set icp_port and icp_access explicitly when using these options.
2393 The defaults will prevent peer traffic using ICP.
2396 no-query Disable ICP queries to this neighbor.
2399 Indicates the named peer is a member of a multicast group.
2400 ICP queries will not be sent directly to the peer, but ICP
2401 replies will be accepted from it.
2403 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2404 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2407 To only send ICP queries to this neighbor infrequently.
2408 This is used to keep the neighbor round trip time updated
2409 and is usually used in conjunction with weighted-round-robin.
2412 ==== HTCP OPTIONS ====
2414 You MUST also set htcp_port and htcp_access explicitly when using these options.
2415 The defaults will prevent peer traffic using HTCP.
2418 htcp Send HTCP, instead of ICP, queries to the neighbor.
2419 You probably also want to set the "icp-port" to 4827
2420 instead of 3130. This directive accepts a comma separated
2421 list of options described below.
2423 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2425 htcp=no-clr Send HTCP to the neighbor but without
2426 sending any CLR requests. This cannot be used with
2429 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2430 This cannot be used with no-clr.
2433 Send HTCP to the neighbor including CLRs but only when
2434 they do not result from PURGE requests.
2437 Forward any HTCP CLR requests this proxy receives to the peer.
2440 ==== PEER SELECTION METHODS ====
2442 The default peer selection method is ICP, with the first responding peer
2443 being used as source. These options can be used for better load balancing.
2446 default This is a parent cache which can be used as a "last-resort"
2447 if a peer cannot be located by any of the peer-selection methods.
2448 If specified more than once, only the first is used.
2450 round-robin Load-Balance parents which should be used in a round-robin
2451 fashion in the absence of any ICP queries.
2452 weight=N can be used to add bias.
2454 weighted-round-robin
2455 Load-Balance parents which should be used in a round-robin
2456 fashion with the frequency of each parent being based on the
2457 round trip time. Closer parents are used more often.
2458 Usually used for background-ping parents.
2459 weight=N can be used to add bias.
2461 carp Load-Balance parents which should be used as a CARP array.
2462 The requests will be distributed among the parents based on the
2463 CARP load balancing hash function based on their weight.
2465 userhash Load-balance parents based on the client proxy_auth or ident username.
2467 sourcehash Load-balance parents based on the client source IP.
2470 To be used only for cache peers of type "multicast".
2471 ALL members of this multicast group have "sibling"
2472 relationship with it, not "parent". This is to a multicast
2473 group when the requested object would be fetched only from
2474 a "parent" cache, anyway. It's useful, e.g., when
2475 configuring a pool of redundant Squid proxies, being
2476 members of the same multicast group.
2479 ==== PEER SELECTION OPTIONS ====
2481 weight=N use to affect the selection of a peer during any weighted
2482 peer-selection mechanisms.
2483 The weight must be an integer; default is 1,
2484 larger weights are favored more.
2485 This option does not affect parent selection if a peering
2486 protocol is not in use.
2488 basetime=N Specify a base amount to be subtracted from round trip
2490 It is subtracted before division by weight in calculating
2491 which parent to fectch from. If the rtt is less than the
2492 base time the rtt is set to a minimal value.
2494 ttl=N Specify a TTL to use when sending multicast ICP queries
2496 Only useful when sending to a multicast group.
2497 Because we don't accept ICP replies from random
2498 hosts, you must configure other group members as
2499 peers with the 'multicast-responder' option.
2501 no-delay To prevent access to this neighbor from influencing the
2504 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2505 enabled) for this host from the specified URL rather
2506 than the Squid default location.
2509 ==== CARP OPTIONS ====
2511 carp-key=key-specification
2512 use a different key than the full URL to hash against the peer.
2513 the key-specification is a comma-separated list of the keywords
2514 scheme, host, port, path, params
2515 Order is not important.
2517 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2519 originserver Causes this parent to be contacted as an origin server.
2520 Meant to be used in accelerator setups when the peer
2524 Set the Host header of requests forwarded to this peer.
2525 Useful in accelerator setups where the server (peer)
2526 expects a certain domain name but clients may request
2527 others. ie example.com or www.example.com
2529 no-digest Disable request of cache digests.
2532 Disables requesting ICMP RTT database (NetDB).
2535 ==== AUTHENTICATION OPTIONS ====
2538 If this is a personal/workgroup proxy and your parent
2539 requires proxy authentication.
2541 Note: The string can include URL escapes (i.e. %20 for
2542 spaces). This also means % must be written as %%.
2545 Send login details received from client to this peer.
2546 Both Proxy- and WWW-Authorization headers are passed
2547 without alteration to the peer.
2548 Authentication is not required by Squid for this to work.
2550 Note: This will pass any form of authentication but
2551 only Basic auth will work through a proxy unless the
2552 connection-auth options are also used.
2554 login=PASS Send login details received from client to this peer.
2555 Authentication is not required by this option.
2557 If there are no client-provided authentication headers
2558 to pass on, but username and password are available
2559 from an external ACL user= and password= result tags
2560 they may be sent instead.
2562 Note: To combine this with proxy_auth both proxies must
2563 share the same user database as HTTP only allows for
2564 a single login (one for proxy, one for origin server).
2565 Also be warned this will expose your users proxy
2566 password to the peer. USE WITH CAUTION
2569 Send the username to the upstream cache, but with a
2570 fixed password. This is meant to be used when the peer
2571 is in another administrative domain, but it is still
2572 needed to identify each user.
2573 The star can optionally be followed by some extra
2574 information which is added to the username. This can
2575 be used to identify this proxy to the peer, similar to
2576 the login=username:password option above.
2579 If this is a personal/workgroup proxy and your parent
2580 requires a secure proxy authentication.
2581 The first principal from the default keytab or defined by
2582 the environment variable KRB5_KTNAME will be used.
2584 WARNING: The connection may transmit requests from multiple
2585 clients. Negotiate often assumes end-to-end authentication
2586 and a single-client. Which is not strictly true here.
2588 login=NEGOTIATE:principal_name
2589 If this is a personal/workgroup proxy and your parent
2590 requires a secure proxy authentication.
2591 The principal principal_name from the default keytab or
2592 defined by the environment variable KRB5_KTNAME will be
2595 WARNING: The connection may transmit requests from multiple
2596 clients. Negotiate often assumes end-to-end authentication
2597 and a single-client. Which is not strictly true here.
2599 connection-auth=on|off
2600 Tell Squid that this peer does or not support Microsoft
2601 connection oriented authentication, and any such
2602 challenges received from there should be ignored.
2603 Default is auto to automatically determine the status
2607 ==== SSL / HTTPS / TLS OPTIONS ====
2609 ssl Encrypt connections to this peer with SSL/TLS.
2611 sslcert=/path/to/ssl/certificate
2612 A client SSL certificate to use when connecting to
2615 sslkey=/path/to/ssl/key
2616 The private SSL key corresponding to sslcert above.
2617 If 'sslkey' is not specified 'sslcert' is assumed to
2618 reference a combined file containing both the
2619 certificate and the key.
2621 sslversion=1|2|3|4|5|6
2622 The SSL version to use when connecting to this peer
2623 1 = automatic (default)
2630 sslcipher=... The list of valid SSL ciphers to use when connecting
2633 ssloptions=... Specify various SSL implementation options:
2635 NO_SSLv2 Disallow the use of SSLv2
2636 NO_SSLv3 Disallow the use of SSLv3
2637 NO_TLSv1 Disallow the use of TLSv1.0
2638 NO_TLSv1_1 Disallow the use of TLSv1.1
2639 NO_TLSv1_2 Disallow the use of TLSv1.2
2641 Always create a new key when using
2642 temporary/ephemeral DH key exchanges
2643 ALL Enable various bug workarounds
2644 suggested as "harmless" by OpenSSL
2645 Be warned that this reduces SSL/TLS
2646 strength to some attacks.
2648 See the OpenSSL SSL_CTX_set_options documentation for a
2651 sslcafile=... A file containing additional CA certificates to use
2652 when verifying the peer certificate.
2654 sslcapath=... A directory containing additional CA certificates to
2655 use when verifying the peer certificate.
2657 sslcrlfile=... A certificate revocation list file to use when
2658 verifying the peer certificate.
2660 sslflags=... Specify various flags modifying the SSL implementation:
2663 Accept certificates even if they fail to
2666 Don't use the default CA list built in
2669 Don't verify the peer certificate
2670 matches the server name
2672 ssldomain= The peer name as advertised in it's certificate.
2673 Used for verifying the correctness of the received peer
2674 certificate. If not specified the peer hostname will be
2678 Enable the "Front-End-Https: On" header needed when
2679 using Squid as a SSL frontend in front of Microsoft OWA.
2680 See MS KB document Q307347 for details on this header.
2681 If set to auto the header will only be added if the
2682 request is forwarded as a https:// URL.
2685 ==== GENERAL OPTIONS ====
2688 A peer-specific connect timeout.
2689 Also see the peer_connect_timeout directive.
2691 connect-fail-limit=N
2692 How many times connecting to a peer must fail before
2693 it is marked as down. Default is 10.
2695 allow-miss Disable Squid's use of only-if-cached when forwarding
2696 requests to siblings. This is primarily useful when
2697 icp_hit_stale is used by the sibling. To extensive use
2698 of this option may result in forwarding loops, and you
2699 should avoid having two-way peerings with this option.
2700 For example to deny peer usage on requests from peer
2701 by denying cache_peer_access if the source is a peer.
2703 max-conn=N Limit the amount of connections Squid may open to this
2706 name=xxx Unique name for the peer.
2707 Required if you have multiple peers on the same host
2708 but different ports.
2709 This name can be used in cache_peer_access and similar
2710 directives to dentify the peer.
2711 Can be used by outgoing access controls through the
2714 no-tproxy Do not use the client-spoof TPROXY support when forwarding
2715 requests to this peer. Use normal address selection instead.
2717 proxy-only objects fetched from the peer will not be stored locally.
2721 NAME: cache_peer_domain cache_host_domain
2726 Use to limit the domains for which a neighbor cache will be
2729 cache_peer_domain cache-host domain [domain ...]
2730 cache_peer_domain cache-host !domain
2732 For example, specifying
2734 cache_peer_domain parent.foo.net .edu
2736 has the effect such that UDP query packets are sent to
2737 'bigserver' only when the requested object exists on a
2738 server in the .edu domain. Prefixing the domainname
2739 with '!' means the cache will be queried for objects
2742 NOTE: * Any number of domains may be given for a cache-host,
2743 either on the same or separate lines.
2744 * When multiple domains are given for a particular
2745 cache-host, the first matched domain is applied.
2746 * Cache hosts with no domain restrictions are queried
2748 * There are no defaults.
2749 * There is also a 'cache_peer_access' tag in the ACL
2753 NAME: cache_peer_access
2758 Similar to 'cache_peer_domain' but provides more flexibility by
2761 cache_peer_access cache-host allow|deny [!]aclname ...
2763 The syntax is identical to 'http_access' and the other lists of
2764 ACL elements. See the comments for 'http_access' below, or
2765 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
2768 NAME: neighbor_type_domain
2769 TYPE: hostdomaintype
2773 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
2775 Modifying the neighbor type for specific domains is now
2776 possible. You can treat some domains differently than the
2777 default neighbor type specified on the 'cache_peer' line.
2778 Normally it should only be necessary to list domains which
2779 should be treated differently because the default neighbor type
2780 applies for hostnames which do not match domains listed here.
2783 cache_peer cache.foo.org parent 3128 3130
2784 neighbor_type_domain cache.foo.org sibling .com .net
2785 neighbor_type_domain cache.foo.org sibling .au .de
2788 NAME: dead_peer_timeout
2792 LOC: Config.Timeout.deadPeer
2794 This controls how long Squid waits to declare a peer cache
2795 as "dead." If there are no ICP replies received in this
2796 amount of time, Squid will declare the peer dead and not
2797 expect to receive any further ICP replies. However, it
2798 continues to send ICP queries, and will mark the peer as
2799 alive upon receipt of the first subsequent ICP reply.
2801 This timeout also affects when Squid expects to receive ICP
2802 replies from peers. If more than 'dead_peer' seconds have
2803 passed since the last ICP reply was received, Squid will not
2804 expect to receive an ICP reply on the next query. Thus, if
2805 your time between requests is greater than this timeout, you
2806 will see a lot of requests sent DIRECT to origin servers
2807 instead of to your parents.
2810 NAME: forward_max_tries
2813 LOC: Config.forward_max_tries
2815 Controls how many different forward paths Squid will try
2816 before giving up. See also forward_timeout.
2818 NOTE: connect_retries (default: none) can make each of these
2819 possible forwarding paths be tried multiple times.
2822 NAME: hierarchy_stoplist
2825 LOC: Config.hierarchy_stoplist
2827 A list of words which, if found in a URL, cause the object to
2828 be handled directly by this cache. In other words, use this
2829 to not query neighbor caches for certain objects. You may
2830 list this option multiple times.
2833 hierarchy_stoplist cgi-bin ?
2835 Note: never_direct overrides this option.
2839 MEMORY CACHE OPTIONS
2840 -----------------------------------------------------------------------------
2847 LOC: Config.memMaxSize
2849 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
2850 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
2851 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
2852 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
2854 'cache_mem' specifies the ideal amount of memory to be used
2856 * In-Transit objects
2858 * Negative-Cached objects
2860 Data for these objects are stored in 4 KB blocks. This
2861 parameter specifies the ideal upper limit on the total size of
2862 4 KB blocks allocated. In-Transit objects take the highest
2865 In-transit objects have priority over the others. When
2866 additional space is needed for incoming data, negative-cached
2867 and hot objects will be released. In other words, the
2868 negative-cached and hot objects will fill up any unused space
2869 not needed for in-transit objects.
2871 If circumstances require, this limit will be exceeded.
2872 Specifically, if your incoming request rate requires more than
2873 'cache_mem' of memory to hold in-transit objects, Squid will
2874 exceed this limit to satisfy the new requests. When the load
2875 decreases, blocks will be freed until the high-water mark is
2876 reached. Thereafter, blocks will be used to store hot
2879 If shared memory caching is enabled, Squid does not use the shared
2880 cache space for in-transit objects, but they still consume as much
2881 local memory as they need. For more details about the shared memory
2882 cache, see memory_cache_shared.
2885 NAME: maximum_object_size_in_memory
2889 LOC: Config.Store.maxInMemObjSize
2891 Objects greater than this size will not be attempted to kept in
2892 the memory cache. This should be set high enough to keep objects
2893 accessed frequently in memory to improve performance whilst low
2894 enough to keep larger objects from hoarding cache_mem.
2897 NAME: memory_cache_shared
2900 LOC: Config.memShared
2902 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
2904 Controls whether the memory cache is shared among SMP workers.
2906 The shared memory cache is meant to occupy cache_mem bytes and replace
2907 the non-shared memory cache, although some entities may still be
2908 cached locally by workers for now (e.g., internal and in-transit
2909 objects may be served from a local memory cache even if shared memory
2910 caching is enabled).
2912 By default, the memory cache is shared if and only if all of the
2913 following conditions are satisfied: Squid runs in SMP mode with
2914 multiple workers, cache_mem is positive, and Squid environment
2915 supports required IPC primitives (e.g., POSIX shared memory segments
2916 and GCC-style atomic operations).
2918 To avoid blocking locks, shared memory uses opportunistic algorithms
2919 that do not guarantee that every cachable entity that could have been
2920 shared among SMP workers will actually be shared.
2922 Currently, entities exceeding 32KB in size cannot be shared.
2925 NAME: memory_cache_mode
2930 Controls which objects to keep in the memory cache (cache_mem)
2932 always Keep most recently fetched objects in memory (default)
2934 disk Only disk cache hits are kept in memory, which means
2935 an object must first be cached on disk and then hit
2936 a second time before cached in memory.
2938 network Only objects fetched from network is kept in memory
2941 NAME: memory_replacement_policy
2943 LOC: Config.memPolicy
2946 The memory replacement policy parameter determines which
2947 objects are purged from memory when memory space is needed.
2949 See cache_replacement_policy for details.
2954 -----------------------------------------------------------------------------
2957 NAME: cache_replacement_policy
2959 LOC: Config.replPolicy
2962 The cache replacement policy parameter determines which
2963 objects are evicted (replaced) when disk space is needed.
2965 lru : Squid's original list based LRU policy
2966 heap GDSF : Greedy-Dual Size Frequency
2967 heap LFUDA: Least Frequently Used with Dynamic Aging
2968 heap LRU : LRU policy implemented using a heap
2970 Applies to any cache_dir lines listed below this.
2972 The LRU policies keeps recently referenced objects.
2974 The heap GDSF policy optimizes object hit rate by keeping smaller
2975 popular objects in cache so it has a better chance of getting a
2976 hit. It achieves a lower byte hit rate than LFUDA though since
2977 it evicts larger (possibly popular) objects.
2979 The heap LFUDA policy keeps popular objects in cache regardless of
2980 their size and thus optimizes byte hit rate at the expense of
2981 hit rate since one large, popular object will prevent many
2982 smaller, slightly less popular objects from being cached.
2984 Both policies utilize a dynamic aging mechanism that prevents
2985 cache pollution that can otherwise occur with frequency-based
2986 replacement policies.
2988 NOTE: if using the LFUDA replacement policy you should increase
2989 the value of maximum_object_size above its default of 4096 KB to
2990 to maximize the potential byte hit rate improvement of LFUDA.
2992 For more information about the GDSF and LFUDA cache replacement
2993 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
2994 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3000 LOC: Config.cacheSwap
3004 cache_dir Type Directory-Name Fs-specific-data [options]
3006 You can specify multiple cache_dir lines to spread the
3007 cache among different disk partitions.
3009 Type specifies the kind of storage system to use. Only "ufs"
3010 is built by default. To enable any of the other storage systems
3011 see the --enable-storeio configure option.
3013 'Directory' is a top-level directory where cache swap
3014 files will be stored. If you want to use an entire disk
3015 for caching, this can be the mount-point directory.
3016 The directory must exist and be writable by the Squid
3017 process. Squid will NOT create this directory for you.
3019 In SMP configurations, cache_dir must not precede the workers option
3020 and should use configuration macros or conditionals to give each
3021 worker interested in disk caching a dedicated cache directory.
3025 "ufs" is the old well-known Squid storage format that has always
3028 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3030 'Mbytes' is the amount of disk space (MB) to use under this
3031 directory. The default is 100 MB. Change this to suit your
3032 configuration. Do NOT put the size of your disk drive here.
3033 Instead, if you want Squid to use the entire disk drive,
3034 subtract 20% and use that value.
3036 'L1' is the number of first-level subdirectories which
3037 will be created under the 'Directory'. The default is 16.
3039 'L2' is the number of second-level subdirectories which
3040 will be created under each first-level directory. The default
3043 The aufs store type:
3045 "aufs" uses the same storage format as "ufs", utilizing
3046 POSIX-threads to avoid blocking the main Squid process on
3047 disk-I/O. This was formerly known in Squid as async-io.
3049 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3051 see argument descriptions under ufs above
3053 The diskd store type:
3055 "diskd" uses the same storage format as "ufs", utilizing a
3056 separate process to avoid blocking the main Squid process on
3059 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3061 see argument descriptions under ufs above
3063 Q1 specifies the number of unacknowledged I/O requests when Squid
3064 stops opening new files. If this many messages are in the queues,
3065 Squid won't open new files. Default is 64
3067 Q2 specifies the number of unacknowledged messages when Squid
3068 starts blocking. If this many messages are in the queues,
3069 Squid blocks until it receives some replies. Default is 72
3071 When Q1 < Q2 (the default), the cache directory is optimized
3072 for lower response time at the expense of a decrease in hit
3073 ratio. If Q1 > Q2, the cache directory is optimized for
3074 higher hit ratio at the expense of an increase in response
3077 The rock store type:
3079 cache_dir rock Directory-Name Mbytes <max-size=bytes> [options]
3081 The Rock Store type is a database-style storage. All cached
3082 entries are stored in a "database" file, using fixed-size slots,
3083 one entry per slot. The database size is specified in MB. The
3084 slot size is specified in bytes using the max-size option. See
3085 below for more info on the max-size option.
3087 swap-timeout=msec: Squid will not start writing a miss to or
3088 reading a hit from disk if it estimates that the swap operation
3089 will take more than the specified number of milliseconds. By
3090 default and when set to zero, disables the disk I/O time limit
3091 enforcement. Ignored when using blocking I/O module because
3092 blocking synchronous I/O does not allow Squid to estimate the
3093 expected swap wait time.
3095 max-swap-rate=swaps/sec: Artificially limits disk access using
3096 the specified I/O rate limit. Swap out requests that
3097 would cause the average I/O rate to exceed the limit are
3098 delayed. Individual swap in requests (i.e., hits or reads) are
3099 not delayed, but they do contribute to measured swap rate and
3100 since they are placed in the same FIFO queue as swap out
3101 requests, they may wait longer if max-swap-rate is smaller.
3102 This is necessary on file systems that buffer "too
3103 many" writes and then start blocking Squid and other processes
3104 while committing those writes to disk. Usually used together
3105 with swap-timeout to avoid excessive delays and queue overflows
3106 when disk demand exceeds available disk "bandwidth". By default
3107 and when set to zero, disables the disk I/O rate limit
3108 enforcement. Currently supported by IpcIo module only.
3111 The coss store type:
3113 NP: COSS filesystem in Squid-3 has been deemed too unstable for
3114 production use and has thus been removed from this release.
3115 We hope that it can be made usable again soon.
3117 block-size=n defines the "block size" for COSS cache_dir's.
3118 Squid uses file numbers as block numbers. Since file numbers
3119 are limited to 24 bits, the block size determines the maximum
3120 size of the COSS partition. The default is 512 bytes, which
3121 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
3122 you should not change the coss block size after Squid
3123 has written some objects to the cache_dir.
3125 The coss file store has changed from 2.5. Now it uses a file
3126 called 'stripe' in the directory names in the config - and
3127 this will be created by squid -z.
3131 no-store, no new objects should be stored to this cache_dir
3133 min-size=n, refers to the min object size in bytes this cache_dir
3134 will accept. It's used to restrict a cache_dir to only store
3135 large objects (e.g. aufs) while other storedirs are optimized
3136 for smaller objects (e.g. COSS). Defaults to 0.
3138 max-size=n, refers to the max object size in bytes this cache_dir
3139 supports. It is used to select the cache_dir to store the object.
3140 Note: To make optimal use of the max-size limits you should order
3141 the cache_dir lines with the smallest max-size value first and the
3142 ones with no max-size specification last.
3144 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
3145 which can be changed with the --with-coss-membuf-size=N configure
3149 # Uncomment and adjust the following to add a disk cache directory.
3150 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3154 NAME: store_dir_select_algorithm
3156 LOC: Config.store_dir_select_algorithm
3159 Set this to 'round-robin' as an alternative.
3162 NAME: max_open_disk_fds
3164 LOC: Config.max_open_disk_fds
3167 To avoid having disk as the I/O bottleneck Squid can optionally
3168 bypass the on-disk cache if more than this amount of disk file
3169 descriptors are open.
3171 A value of 0 indicates no limit.
3174 NAME: minimum_object_size
3178 LOC: Config.Store.minObjectSize
3180 Objects smaller than this size will NOT be saved on disk. The
3181 value is specified in kilobytes, and the default is 0 KB, which
3182 means there is no minimum.
3185 NAME: maximum_object_size
3189 LOC: Config.Store.maxObjectSize
3191 Objects larger than this size will NOT be saved on disk. The
3192 value is specified in kilobytes, and the default is 4MB. If
3193 you wish to get a high BYTES hit ratio, you should probably
3194 increase this (one 32 MB object hit counts for 3200 10KB
3195 hits). If you wish to increase speed more than your want to
3196 save bandwidth you should leave this low.
3198 NOTE: if using the LFUDA replacement policy you should increase
3199 this value to maximize the byte hit rate improvement of LFUDA!
3200 See replacement_policy below for a discussion of this policy.
3203 NAME: cache_swap_low
3204 COMMENT: (percent, 0-100)
3207 LOC: Config.Swap.lowWaterMark
3210 NAME: cache_swap_high
3211 COMMENT: (percent, 0-100)
3214 LOC: Config.Swap.highWaterMark
3217 The low- and high-water marks for cache object replacement.
3218 Replacement begins when the swap (disk) usage is above the
3219 low-water mark and attempts to maintain utilization near the
3220 low-water mark. As swap utilization gets close to high-water
3221 mark object eviction becomes more aggressive. If utilization is
3222 close to the low-water mark less replacement is done each time.
3224 Defaults are 90% and 95%. If you have a large cache, 5% could be
3225 hundreds of MB. If this is the case you may wish to set these
3226 numbers closer together.
3231 -----------------------------------------------------------------------------
3241 logformat <name> <format specification>
3243 Defines an access log format.
3245 The <format specification> is a string with embedded % format codes
3247 % format codes all follow the same basic structure where all but
3248 the formatcode is optional. Output strings are automatically escaped
3249 as required according to their context and the output format
3250 modifiers are usually not needed, but can be specified if an explicit
3251 output format is desired.
3253 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3255 " output in quoted string format
3256 [ output in squid text log format as used by log_mime_hdrs
3257 # output in URL quoted format
3262 width minimum and/or maximum field width:
3263 [width_min][.width_max]
3264 When minimum starts with 0, the field is zero-padded.
3265 String values exceeding maximum width are truncated.
3267 {arg} argument such as header name etc
3271 % a literal % character
3272 sn Unique sequence number per log line entry
3273 err_code The ID of an error response served by Squid or
3274 a similar internal error identifier.
3275 err_detail Additional err_code-dependent error information.
3276 note The meta header specified by the argument. Also
3277 logs the adaptation meta headers set by the
3278 adaptation_meta configuration parameter.
3279 If no argument given all meta headers logged.
3281 Connection related format codes:
3283 >a Client source IP address
3285 >p Client source port
3286 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3287 >la Local IP address the client connected to
3288 >lp Local port number the client connected to
3290 la Local listening IP address the client connection was connected to.
3291 lp Local listening port number the client connection was connected to.
3293 <a Server IP address of the last server or peer connection
3294 <A Server FQDN or peer name
3295 <p Server port number of the last server or peer connection
3296 <la Local IP address of the last server or peer connection
3297 <lp Local port number of the last server or peer connection
3299 Time related format codes:
3301 ts Seconds since epoch
3302 tu subsecond time (milliseconds)
3303 tl Local time. Optional strftime format argument
3304 default %d/%b/%Y:%H:%M:%S %z
3305 tg GMT time. Optional strftime format argument
3306 default %d/%b/%Y:%H:%M:%S %z
3307 tr Response time (milliseconds)
3308 dt Total time spent making DNS lookups (milliseconds)
3310 Access Control related format codes:
3312 et Tag returned by external acl
3313 ea Log string returned by external acl
3314 un User name (any available)
3315 ul User name from authentication
3316 ue User name from external acl helper
3317 ui User name from ident
3318 us User name from SSL
3320 HTTP related format codes:
3322 [http::]>h Original request header. Optional header name argument
3323 on the format header[:[separator]element]
3324 [http::]>ha The HTTP request headers after adaptation and redirection.
3325 Optional header name argument as for >h
3326 [http::]<h Reply header. Optional header name argument
3328 [http::]>Hs HTTP status code sent to the client
3329 [http::]<Hs HTTP status code received from the next hop
3330 [http::]<bs Number of HTTP-equivalent message body bytes
3331 received from the next hop, excluding chunked
3332 transfer encoding and control messages.
3333 Generated FTP/Gopher listings are treated as
3335 [http::]mt MIME content type
3336 [http::]rm Request method (GET/POST etc)
3337 [http::]>rm Request method from client
3338 [http::]<rm Request method sent to server or peer
3339 [http::]ru Request URL from client (historic, filtered for logging)
3340 [http::]>ru Request URL from client
3341 [http::]<ru Request URL sent to server or peer
3342 [http::]rp Request URL-Path excluding hostname
3343 [http::]>rp Request URL-Path excluding hostname from client
3344 [http::]<rp Request URL-Path excluding hostname sento to server or peer
3345 [http::]rv Request protocol version
3346 [http::]>rv Request protocol version from client
3347 [http::]<rv Request protocol version sent to server or peer
3348 [http::]<st Sent reply size including HTTP headers
3349 [http::]>st Received request size including HTTP headers. In the
3350 case of chunked requests the chunked encoding metadata
3352 [http::]>sh Received HTTP request headers size
3353 [http::]<sh Sent HTTP reply headers size
3354 [http::]st Request+Reply size including HTTP headers
3355 [http::]<sH Reply high offset sent
3356 [http::]<sS Upstream object size
3357 [http::]<pt Peer response time in milliseconds. The timer starts
3358 when the last request byte is sent to the next hop
3359 and stops when the last response byte is received.
3360 [http::]<tt Total server-side time in milliseconds. The timer
3361 starts with the first connect request (or write I/O)
3362 sent to the first selected peer. The timer stops
3363 with the last I/O with the last peer.
3365 Squid handling related format codes:
3367 Ss Squid request status (TCP_MISS etc)
3368 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3370 SSL-related format codes:
3372 ssl::bump_mode SslBump decision for the transaction:
3374 For CONNECT requests that initiated bumping of
3375 a connection and for any request received on
3376 an already bumped connection, Squid logs the
3377 corresponding SslBump mode ("server-first" or
3378 "client-first"). See the ssl_bump option for
3379 more information about these modes.
3381 A "none" token is logged for requests that
3382 triggered "ssl_bump" ACL evaluation matching
3383 either a "none" rule or no rules at all.
3385 In all other cases, a single dash ("-") is
3388 If ICAP is enabled, the following code becomes available (as
3389 well as ICAP log codes documented with the icap_log option):
3391 icap::tt Total ICAP processing time for the HTTP
3392 transaction. The timer ticks when ICAP
3393 ACLs are checked and when ICAP
3394 transaction is in progress.
3396 If adaptation is enabled the following three codes become available:
3398 adapt::<last_h The header of the last ICAP response or
3399 meta-information from the last eCAP
3400 transaction related to the HTTP transaction.
3401 Like <h, accepts an optional header name
3404 adapt::sum_trs Summed adaptation transaction response
3405 times recorded as a comma-separated list in
3406 the order of transaction start time. Each time
3407 value is recorded as an integer number,
3408 representing response time of one or more
3409 adaptation (ICAP or eCAP) transaction in
3410 milliseconds. When a failed transaction is
3411 being retried or repeated, its time is not
3412 logged individually but added to the
3413 replacement (next) transaction. See also:
3416 adapt::all_trs All adaptation transaction response times.
3417 Same as adaptation_strs but response times of
3418 individual transactions are never added
3419 together. Instead, all transaction response
3420 times are recorded individually.
3422 You can prefix adapt::*_trs format codes with adaptation
3423 service name in curly braces to record response time(s) specific
3424 to that service. For example: %{my_service}adapt::sum_trs
3426 If SSL is enabled, the following formating codes become available:
3428 %ssl::>cert_subject The Subject field of the received client
3429 SSL certificate or a dash ('-') if Squid has
3430 received an invalid/malformed certificate or
3431 no certificate at all. Consider encoding the
3432 logged value because Subject often has spaces.
3434 %ssl::>cert_issuer The Issuer field of the received client
3435 SSL certificate or a dash ('-') if Squid has
3436 received an invalid/malformed certificate or
3437 no certificate at all. Consider encoding the
3438 logged value because Issuer often has spaces.
3440 The default formats available (which do not need re-defining) are:
3442 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3443 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3444 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3445 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3446 logformat useragent %>a [%tl] "%{User-Agent}>h"
3448 NOTE: When the log_mime_hdrs directive is set to ON.
3449 The squid, common and combined formats have a safely encoded copy
3450 of the mime headers appended to each line within a pair of brackets.
3452 NOTE: The common and combined formats are not quite true to the Apache definition.
3453 The logs from Squid contain an extra status and hierarchy code appended.
3457 NAME: access_log cache_access_log
3459 LOC: Config.Log.accesslogs
3460 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3462 These files log client request activities. Has a line every HTTP or
3463 ICP request. The format is:
3464 access_log <module>:<place> [<logformat name> [acl acl ...]]
3465 access_log none [acl acl ...]]
3467 Will log to the specified module:place using the specified format (which
3468 must be defined in a logformat directive) those entries which match
3469 ALL the acl's specified (which must be defined in acl clauses).
3470 If no acl is specified, all requests will be logged to this destination.
3472 ===== Modules Currently available =====
3474 none Do not log any requests matching these ACL.
3475 Do not specify Place or logformat name.
3477 stdio Write each log line to disk immediately at the completion of
3479 Place: the filename and path to be written.
3481 daemon Very similar to stdio. But instead of writing to disk the log
3482 line is passed to a daemon helper for asychronous handling instead.
3483 Place: varies depending on the daemon.
3485 log_file_daemon Place: the file name and path to be written.
3487 syslog To log each request via syslog facility.
3488 Place: The syslog facility and priority level for these entries.
3489 Place Format: facility.priority
3491 where facility could be any of:
3492 authpriv, daemon, local0 ... local7 or user.
3494 And priority could be any of:
3495 err, warning, notice, info, debug.
3497 udp To send each log line as text data to a UDP receiver.
3498 Place: The destination host name or IP and port.
3499 Place Format: //host:port
3501 tcp To send each log line as text data to a TCP receiver.
3502 Place: The destination host name or IP and port.
3503 Place Format: //host:port
3506 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3512 LOC: Config.Log.icaplogs
3515 ICAP log files record ICAP transaction summaries, one line per
3518 The icap_log option format is:
3519 icap_log <filepath> [<logformat name> [acl acl ...]]
3520 icap_log none [acl acl ...]]
3522 Please see access_log option documentation for details. The two
3523 kinds of logs share the overall configuration approach and many
3526 ICAP processing of a single HTTP message or transaction may
3527 require multiple ICAP transactions. In such cases, multiple
3528 ICAP transaction log lines will correspond to a single access
3531 ICAP log uses logformat codes that make sense for an ICAP
3532 transaction. Header-related codes are applied to the HTTP header
3533 embedded in an ICAP server response, with the following caveats:
3534 For REQMOD, there is no HTTP response header unless the ICAP
3535 server performed request satisfaction. For RESPMOD, the HTTP
3536 request header is the header sent to the ICAP server. For
3537 OPTIONS, there are no HTTP headers.
3539 The following format codes are also available for ICAP logs:
3541 icap::<A ICAP server IP address. Similar to <A.
3543 icap::<service_name ICAP service name from the icap_service
3544 option in Squid configuration file.
3546 icap::ru ICAP Request-URI. Similar to ru.
3548 icap::rm ICAP request method (REQMOD, RESPMOD, or
3549 OPTIONS). Similar to existing rm.
3551 icap::>st Bytes sent to the ICAP server (TCP payload
3552 only; i.e., what Squid writes to the socket).
3554 icap::<st Bytes received from the ICAP server (TCP
3555 payload only; i.e., what Squid reads from
3558 icap::<bs Number of message body bytes received from the
3559 ICAP server. ICAP message body, if any, usually
3560 includes encapsulated HTTP message headers and
3561 possibly encapsulated HTTP message body. The
3562 HTTP body part is dechunked before its size is
3565 icap::tr Transaction response time (in
3566 milliseconds). The timer starts when
3567 the ICAP transaction is created and
3568 stops when the transaction is completed.
3571 icap::tio Transaction I/O time (in milliseconds). The
3572 timer starts when the first ICAP request
3573 byte is scheduled for sending. The timers
3574 stops when the last byte of the ICAP response
3577 icap::to Transaction outcome: ICAP_ERR* for all
3578 transaction errors, ICAP_OPT for OPTION
3579 transactions, ICAP_ECHO for 204
3580 responses, ICAP_MOD for message
3581 modification, and ICAP_SAT for request
3582 satisfaction. Similar to Ss.
3584 icap::Hs ICAP response status code. Similar to Hs.
3586 icap::>h ICAP request header(s). Similar to >h.
3588 icap::<h ICAP response header(s). Similar to <h.
3590 The default ICAP log format, which can be used without an explicit
3591 definition, is called icap_squid:
3593 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3595 See also: logformat, log_icap, and %adapt::<last_h
3598 NAME: logfile_daemon
3600 DEFAULT: @DEFAULT_LOGFILED@
3601 LOC: Log::TheConfig.logfile_daemon
3603 Specify the path to the logfile-writing daemon. This daemon is
3604 used to write the access and store logs, if configured.
3606 Squid sends a number of commands to the log daemon:
3607 L<data>\n - logfile data
3612 r<n>\n - set rotate count to <n>
3613 b<n>\n - 1 = buffer output, 0 = don't buffer output
3615 No responses is expected.
3620 LOC: Config.accessList.log
3622 COMMENT: allow|deny acl acl...
3624 This options allows you to control which requests gets logged
3625 to access.log (see access_log directive). Requests denied for
3626 logging will also not be accounted for in performance counters.
3628 This clause only supports fast acl types.
3629 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3635 LOC: Config.accessList.icap
3638 This options allows you to control which requests get logged
3639 to icap.log. See the icap_log directive for ICAP log details.
3642 NAME: cache_store_log
3645 LOC: Config.Log.store
3647 Logs the activities of the storage manager. Shows which
3648 objects are ejected from the cache, and which objects are
3649 saved and for how long.
3650 There are not really utilities to analyze this data, so you can safely
3651 disable it (the default).
3653 Store log uses modular logging outputs. See access_log for the list
3654 of modules supported.
3657 cache_store_log stdio:@DEFAULT_STORE_LOG@
3658 cache_store_log daemon:@DEFAULT_STORE_LOG@
3661 NAME: cache_swap_state cache_swap_log
3663 LOC: Config.Log.swap
3666 Location for the cache "swap.state" file. This index file holds
3667 the metadata of objects saved on disk. It is used to rebuild
3668 the cache during startup. Normally this file resides in each
3669 'cache_dir' directory, but you may specify an alternate
3670 pathname here. Note you must give a full filename, not just
3671 a directory. Since this is the index for the whole object
3672 list you CANNOT periodically rotate it!
3674 If %s can be used in the file name it will be replaced with a
3675 a representation of the cache_dir name where each / is replaced
3676 with '.'. This is needed to allow adding/removing cache_dir
3677 lines when cache_swap_log is being used.
3679 If have more than one 'cache_dir', and %s is not used in the name
3680 these swap logs will have names such as:
3686 The numbered extension (which is added automatically)
3687 corresponds to the order of the 'cache_dir' lines in this
3688 configuration file. If you change the order of the 'cache_dir'
3689 lines in this file, these index files will NOT correspond to
3690 the correct 'cache_dir' entry (unless you manually rename
3691 them). We recommend you do NOT use this option. It is
3692 better to keep these index files in each 'cache_dir' directory.
3695 NAME: logfile_rotate
3698 LOC: Config.Log.rotateNumber
3700 Specifies the number of logfile rotations to make when you
3701 type 'squid -k rotate'. The default is 10, which will rotate
3702 with extensions 0 through 9. Setting logfile_rotate to 0 will
3703 disable the file name rotation, but the logfiles are still closed
3704 and re-opened. This will enable you to rename the logfiles
3705 yourself just before sending the rotate signal.
3707 Note, the 'squid -k rotate' command normally sends a USR1
3708 signal to the running squid process. In certain situations
3709 (e.g. on Linux with Async I/O), USR1 is used for other
3710 purposes, so -k rotate uses another signal. It is best to get
3711 in the habit of using 'squid -k rotate' instead of 'kill -USR1
3714 Note, from Squid-3.1 this option has no effect on the cache.log,
3715 that log can be rotated separately by using debug_options
3718 NAME: emulate_httpd_log
3721 Replace this with an access_log directive using the format 'common' or 'combined'.
3724 NAME: log_ip_on_direct
3727 Remove this option from your config. To log server or peer names use %<A in the log format.
3732 DEFAULT: @DEFAULT_MIME_TABLE@
3733 LOC: Config.mimeTablePathname
3735 Pathname to Squid's MIME table. You shouldn't need to change
3736 this, but the default file contains examples and formatting
3737 information if you do.
3743 LOC: Config.onoff.log_mime_hdrs
3746 The Cache can record both the request and the response MIME
3747 headers for each HTTP transaction. The headers are encoded
3748 safely and will appear as two bracketed fields at the end of
3749 the access log (for either the native or httpd-emulated log
3750 formats). To enable this logging set log_mime_hdrs to 'on'.
3756 Replace this with an access_log directive using the format 'useragent'.
3759 NAME: referer_log referrer_log
3762 Replace this with an access_log directive using the format 'referrer'.
3767 DEFAULT: @DEFAULT_PID_FILE@
3768 LOC: Config.pidFilename
3770 A filename to write the process-id to. To disable, enter "none".
3776 Remove this option from your config. To log FQDN use %>A in the log format.
3779 NAME: client_netmask
3781 LOC: Config.Addrs.client_netmask
3784 A netmask for client addresses in logfiles and cachemgr output.
3785 Change this to protect the privacy of your cache clients.
3786 A netmask of 255.255.255.0 will log all IP's in that range with
3787 the last digit set to '0'.
3793 Use a regular access.log with ACL limiting it to MISS events.
3796 NAME: strip_query_terms
3798 LOC: Config.onoff.strip_query_terms
3801 By default, Squid strips query terms from requested URLs before
3802 logging. This protects your user's privacy.
3809 LOC: Config.onoff.buffered_logs
3811 cache.log log file is written with stdio functions, and as such
3812 it can be buffered or unbuffered. By default it will be unbuffered.
3813 Buffering it can speed up the writing slightly (though you are
3814 unlikely to need to worry unless you run with tons of debugging
3815 enabled in which case performance will suffer badly anyway..).
3818 NAME: netdb_filename
3820 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
3821 LOC: Config.netdbFilename
3824 A filename where Squid stores it's netdb state between restarts.
3825 To disable, enter "none".
3829 OPTIONS FOR TROUBLESHOOTING
3830 -----------------------------------------------------------------------------
3835 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
3836 LOC: Debug::cache_log
3838 Cache logging file. This is where general information about
3839 your cache's behavior goes. You can increase the amount of data
3840 logged to this file and how often its rotated with "debug_options"
3846 LOC: Debug::debugOptions
3848 Logging options are set as section,level where each source file
3849 is assigned a unique section. Lower levels result in less
3850 output, Full debugging (level 9) can result in a very large
3851 log file, so be careful.
3853 The magic word "ALL" sets debugging levels for all sections.
3854 We recommend normally running with "ALL,1".
3856 The rotate=N option can be used to keep more or less of these logs
3857 than would otherwise be kept by logfile_rotate.
3858 For most uses a single log should be enough to monitor current
3859 events affecting Squid.
3864 LOC: Config.coredump_dir
3865 DEFAULT_IF_NONE: none
3867 By default Squid leaves core files in the directory from where
3868 it was started. If you set 'coredump_dir' to a directory
3869 that exists, Squid will chdir() to that directory at startup
3870 and coredump files will be left there.
3874 # Leave coredumps in the first cache dir
3875 coredump_dir @DEFAULT_SWAP_DIR@
3881 OPTIONS FOR FTP GATEWAYING
3882 -----------------------------------------------------------------------------
3888 LOC: Config.Ftp.anon_user
3890 If you want the anonymous login password to be more informative
3891 (and enable the use of picky ftp servers), set this to something
3892 reasonable for your domain, like wwwuser@somewhere.net
3894 The reason why this is domainless by default is the
3895 request can be made on the behalf of a user in any domain,
3896 depending on how the cache is used.
3897 Some ftp server also validate the email address is valid
3898 (for example perl.com).
3904 LOC: Config.Ftp.passive
3906 If your firewall does not allow Squid to use passive
3907 connections, turn off this option.
3909 Use of ftp_epsv_all option requires this to be ON.
3915 LOC: Config.Ftp.epsv_all
3917 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
3919 NATs may be able to put the connection on a "fast path" through the
3920 translator, as the EPRT command will never be used and therefore,
3921 translation of the data portion of the segments will never be needed.
3923 When a client only expects to do two-way FTP transfers this may be
3925 If squid finds that it must do a three-way FTP transfer after issuing
3926 an EPSV ALL command, the FTP session will fail.
3928 If you have any doubts about this option do not use it.
3929 Squid will nicely attempt all other connection methods.
3931 Requires ftp_passive to be ON (default) for any effect.
3937 LOC: Config.Ftp.epsv
3939 FTP Protocol extensions permit the use of a special "EPSV" command.
3941 NATs may be able to put the connection on a "fast path" through the
3942 translator using EPSV, as the EPRT command will never be used
3943 and therefore, translation of the data portion of the segments
3944 will never be needed.
3946 Turning this OFF will prevent EPSV being attempted.
3947 WARNING: Doing so will convert Squid back to the old behavior with all
3948 the related problems with external NAT devices/layers.
3950 Requires ftp_passive to be ON (default) for any effect.
3956 LOC: Config.Ftp.eprt
3958 FTP Protocol extensions permit the use of a special "EPRT" command.
3960 This extension provides a protocol neutral alternative to the
3961 IPv4-only PORT command. When supported it enables active FTP data
3962 channels over IPv6 and efficient NAT handling.
3964 Turning this OFF will prevent EPRT being attempted and will skip
3965 straight to using PORT for IPv4 servers.
3967 Some devices are known to not handle this extension correctly and
3968 may result in crashes. Devices which suport EPRT enough to fail
3969 cleanly will result in Squid attempting PORT anyway. This directive
3970 should only be disabled when EPRT results in device failures.
3972 WARNING: Doing so will convert Squid back to the old behavior with all
3973 the related problems with external NAT devices/layers and IPv4-only FTP.
3976 NAME: ftp_sanitycheck
3979 LOC: Config.Ftp.sanitycheck
3981 For security and data integrity reasons Squid by default performs
3982 sanity checks of the addresses of FTP data connections ensure the
3983 data connection is to the requested server. If you need to allow
3984 FTP connections to servers using another IP address for the data
3985 connection turn this off.
3988 NAME: ftp_telnet_protocol
3991 LOC: Config.Ftp.telnet
3993 The FTP protocol is officially defined to use the telnet protocol
3994 as transport channel for the control connection. However, many
3995 implementations are broken and does not respect this aspect of
3998 If you have trouble accessing files with ASCII code 255 in the
3999 path or similar problems involving this ASCII code you can
4000 try setting this directive to off. If that helps, report to the
4001 operator of the FTP server in question that their FTP server
4002 is broken and does not follow the FTP standard.
4006 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4007 -----------------------------------------------------------------------------
4012 DEFAULT: @DEFAULT_DISKD@
4013 LOC: Config.Program.diskd
4015 Specify the location of the diskd executable.
4016 Note this is only useful if you have compiled in
4017 diskd as one of the store io modules.
4020 NAME: unlinkd_program
4023 DEFAULT: @DEFAULT_UNLINKD@
4024 LOC: Config.Program.unlinkd
4026 Specify the location of the executable for file deletion process.
4029 NAME: pinger_program
4031 DEFAULT: @DEFAULT_PINGER@
4032 LOC: Config.pinger.program
4035 Specify the location of the executable for the pinger process.
4041 LOC: Config.pinger.enable
4044 Control whether the pinger is active at run-time.
4045 Enables turning ICMP pinger on and off with a simple
4046 squid -k reconfigure.
4051 OPTIONS FOR URL REWRITING
4052 -----------------------------------------------------------------------------
4055 NAME: url_rewrite_program redirect_program
4057 LOC: Config.Program.redirect
4060 Specify the location of the executable URL rewriter to use.
4061 Since they can perform almost any function there isn't one included.
4063 For each requested URL, the rewriter will receive on line with the format
4065 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
4067 In the future, the rewriter interface will be extended with
4068 key=value pairs ("kvpairs" shown above). Rewriter programs
4069 should be prepared to receive and possibly ignore additional
4070 whitespace-separated tokens on each input line.
4072 And the rewriter may return a rewritten URL. The other components of
4073 the request line does not need to be returned (ignored if they are).
4075 The rewriter can also indicate that a client-side redirect should
4076 be performed to the new URL. This is done by prefixing the returned
4077 URL with "301:" (moved permanently) or 302: (moved temporarily), etc.
4079 By default, a URL rewriter is not used.
4082 NAME: url_rewrite_children redirect_children
4083 TYPE: HelperChildConfig
4084 DEFAULT: 20 startup=0 idle=1 concurrency=0
4085 LOC: Config.redirectChildren
4087 The maximum number of redirector processes to spawn. If you limit
4088 it too few Squid will have to wait for them to process a backlog of
4089 URLs, slowing it down. If you allow too many they will use RAM
4090 and other system resources noticably.
4092 The startup= and idle= options allow some measure of skew in your
4097 Sets a minimum of how many processes are to be spawned when Squid
4098 starts or reconfigures. When set to zero the first request will
4099 cause spawning of the first child process to handle it.
4101 Starting too few will cause an initial slowdown in traffic as Squid
4102 attempts to simultaneously spawn enough processes to cope.
4106 Sets a minimum of how many processes Squid is to try and keep available
4107 at all times. When traffic begins to rise above what the existing
4108 processes can handle this many more will be spawned up to the maximum
4109 configured. A minimum setting of 1 is required.
4113 The number of requests each redirector helper can handle in
4114 parallel. Defaults to 0 which indicates the redirector
4115 is a old-style single threaded redirector.
4117 When this directive is set to a value >= 1 then the protocol
4118 used to communicate with the helper is modified to include
4119 a request ID in front of the request/response. The request
4120 ID from the request must be echoed back with the response
4124 NAME: url_rewrite_host_header redirect_rewrites_host_header
4127 LOC: Config.onoff.redir_rewrites_host
4129 To preserve same-origin security policies in browsers and
4130 prevent Host: header forgery by redirectors Squid rewrites
4131 any Host: header in redirected requests.
4133 If you are running an accelerator this may not be a wanted
4134 effect of a redirector. This directive enables you disable
4135 Host: alteration in reverse-proxy traffic.
4137 WARNING: Entries are cached on the result of the URL rewriting
4138 process, so be careful if you have domain-virtual hosts.
4140 WARNING: Squid and other software verifies the URL and Host
4141 are matching, so be careful not to relay through other proxies
4142 or inspecting firewalls with this disabled.
4145 NAME: url_rewrite_access redirector_access
4148 LOC: Config.accessList.redirector
4150 If defined, this access list specifies which requests are
4151 sent to the redirector processes. By default all requests
4154 This clause supports both fast and slow acl types.
4155 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4158 NAME: url_rewrite_bypass redirector_bypass
4160 LOC: Config.onoff.redirector_bypass
4163 When this is 'on', a request will not go through the
4164 redirector if all redirectors are busy. If this is 'off'
4165 and the redirector queue grows too large, Squid will exit
4166 with a FATAL error and ask you to increase the number of
4167 redirectors. You should only enable this if the redirectors
4168 are not critical to your caching system. If you use
4169 redirectors for access control, and you enable this option,
4170 users may have access to pages they should not
4171 be allowed to request.
4175 OPTIONS FOR TUNING THE CACHE
4176 -----------------------------------------------------------------------------
4179 NAME: cache no_cache
4182 LOC: Config.accessList.noCache
4184 A list of ACL elements which, if matched and denied, cause the request to
4185 not be satisfied from the cache and the reply to not be cached.
4186 In other words, use this to force certain objects to never be cached.
4188 You must use the words 'allow' or 'deny' to indicate whether items
4189 matching the ACL should be allowed or denied into the cache.
4191 Default is to allow all to be cached.
4193 This clause supports both fast and slow acl types.
4194 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4200 LOC: Config.maxStale
4203 This option puts an upper limit on how stale content Squid
4204 will serve from the cache if cache validation fails.
4205 Can be overriden by the refresh_pattern max-stale option.
4208 NAME: refresh_pattern
4209 TYPE: refreshpattern
4213 usage: refresh_pattern [-i] regex min percent max [options]
4215 By default, regular expressions are CASE-SENSITIVE. To make
4216 them case-insensitive, use the -i option.
4218 'Min' is the time (in minutes) an object without an explicit
4219 expiry time should be considered fresh. The recommended
4220 value is 0, any higher values may cause dynamic applications
4221 to be erroneously cached unless the application designer
4222 has taken the appropriate actions.
4224 'Percent' is a percentage of the objects age (time since last
4225 modification age) an object without explicit expiry time
4226 will be considered fresh.
4228 'Max' is an upper limit on how long objects without an explicit
4229 expiry time will be considered fresh.
4231 options: override-expire
4236 ignore-must-revalidate
4243 override-expire enforces min age even if the server
4244 sent an explicit expiry time (e.g., with the
4245 Expires: header or Cache-Control: max-age). Doing this
4246 VIOLATES the HTTP standard. Enabling this feature
4247 could make you liable for problems which it causes.
4249 Note: override-expire does not enforce staleness - it only extends
4250 freshness / min. If the server returns a Expires time which
4251 is longer than your max time, Squid will still consider
4252 the object fresh for that period of time.
4254 override-lastmod enforces min age even on objects
4255 that were modified recently.
4257 reload-into-ims changes client no-cache or ``reload''
4258 to If-Modified-Since requests. Doing this VIOLATES the
4259 HTTP standard. Enabling this feature could make you
4260 liable for problems which it causes.
4262 ignore-reload ignores a client no-cache or ``reload''
4263 header. Doing this VIOLATES the HTTP standard. Enabling
4264 this feature could make you liable for problems which
4267 ignore-no-store ignores any ``Cache-control: no-store''
4268 headers received from a server. Doing this VIOLATES
4269 the HTTP standard. Enabling this feature could make you
4270 liable for problems which it causes.
4272 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
4273 headers received from a server. Doing this VIOLATES
4274 the HTTP standard. Enabling this feature could make you
4275 liable for problems which it causes.
4277 ignore-private ignores any ``Cache-control: private''
4278 headers received from a server. Doing this VIOLATES
4279 the HTTP standard. Enabling this feature could make you
4280 liable for problems which it causes.
4282 ignore-auth caches responses to requests with authorization,
4283 as if the originserver had sent ``Cache-control: public''
4284 in the response header. Doing this VIOLATES the HTTP standard.
4285 Enabling this feature could make you liable for problems which
4288 refresh-ims causes squid to contact the origin server
4289 when a client issues an If-Modified-Since request. This
4290 ensures that the client will receive an updated version
4291 if one is available.
4293 store-stale stores responses even if they don't have explicit
4294 freshness or a validator (i.e., Last-Modified or an ETag)
4295 present, or if they're already stale. By default, Squid will
4296 not cache such responses because they usually can't be
4297 reused. Note that such responses will be stale by default.
4299 max-stale=NN provide a maximum staleness factor. Squid won't
4300 serve objects more stale than this even if it failed to
4301 validate the object. Default: use the max_stale global limit.
4303 Basically a cached object is:
4305 FRESH if expires < now, else STALE
4307 FRESH if lm-factor < percent, else STALE
4311 The refresh_pattern lines are checked in the order listed here.
4312 The first entry which matches is used. If none of the entries
4313 match the default will be used.
4315 Note, you must uncomment all the default lines if you want
4316 to change one. The default setting is only active if none is
4321 # Add any of your own refresh_pattern entries above these.
4322 refresh_pattern ^ftp: 1440 20% 10080
4323 refresh_pattern ^gopher: 1440 0% 1440
4324 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
4325 refresh_pattern . 0 20% 4320
4329 NAME: quick_abort_min
4333 LOC: Config.quickAbort.min
4336 NAME: quick_abort_max
4340 LOC: Config.quickAbort.max
4343 NAME: quick_abort_pct
4347 LOC: Config.quickAbort.pct
4349 The cache by default continues downloading aborted requests
4350 which are almost completed (less than 16 KB remaining). This
4351 may be undesirable on slow (e.g. SLIP) links and/or very busy
4352 caches. Impatient users may tie up file descriptors and
4353 bandwidth by repeatedly requesting and immediately aborting
4356 When the user aborts a request, Squid will check the
4357 quick_abort values to the amount of data transfered until
4360 If the transfer has less than 'quick_abort_min' KB remaining,
4361 it will finish the retrieval.
4363 If the transfer has more than 'quick_abort_max' KB remaining,
4364 it will abort the retrieval.
4366 If more than 'quick_abort_pct' of the transfer has completed,
4367 it will finish the retrieval.
4369 If you do not want any retrieval to continue after the client
4370 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
4373 If you want retrievals to always continue if they are being
4374 cached set 'quick_abort_min' to '-1 KB'.
4377 NAME: read_ahead_gap
4378 COMMENT: buffer-size
4380 LOC: Config.readAheadGap
4383 The amount of data the cache will buffer ahead of what has been
4384 sent to the client when retrieving an object from another server.
4388 IFDEF: USE_HTTP_VIOLATIONS
4391 LOC: Config.negativeTtl
4394 Set the Default Time-to-Live (TTL) for failed requests.
4395 Certain types of failures (such as "connection refused" and
4396 "404 Not Found") are able to be negatively-cached for a short time.
4397 Modern web servers should provide Expires: header, however if they
4398 do not this can provide a minimum TTL.
4399 The default is not to cache errors with unknown expiry details.
4401 Note that this is different from negative caching of DNS lookups.
4403 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4404 this feature could make you liable for problems which it
4408 NAME: positive_dns_ttl
4411 LOC: Config.positiveDnsTtl
4414 Upper limit on how long Squid will cache positive DNS responses.
4415 Default is 6 hours (360 minutes). This directive must be set
4416 larger than negative_dns_ttl.
4419 NAME: negative_dns_ttl
4422 LOC: Config.negativeDnsTtl
4425 Time-to-Live (TTL) for negative caching of failed DNS lookups.
4426 This also sets the lower cache limit on positive lookups.
4427 Minimum value is 1 second, and it is not recommendable to go
4428 much below 10 seconds.
4431 NAME: range_offset_limit
4432 COMMENT: size [acl acl...]
4434 LOC: Config.rangeOffsetLimit
4437 usage: (size) [units] [[!]aclname]
4439 Sets an upper limit on how far (number of bytes) into the file
4440 a Range request may be to cause Squid to prefetch the whole file.
4441 If beyond this limit, Squid forwards the Range request as it is and
4442 the result is NOT cached.
4444 This is to stop a far ahead range request (lets say start at 17MB)
4445 from making Squid fetch the whole object up to that point before
4446 sending anything to the client.
4448 Multiple range_offset_limit lines may be specified, and they will
4449 be searched from top to bottom on each request until a match is found.
4450 The first match found will be used. If no line matches a request, the
4451 default limit of 0 bytes will be used.
4453 'size' is the limit specified as a number of units.
4455 'units' specifies whether to use bytes, KB, MB, etc.
4456 If no units are specified bytes are assumed.
4458 A size of 0 causes Squid to never fetch more than the
4459 client requested. (default)
4461 A size of 'none' causes Squid to always fetch the object from the
4462 beginning so it may cache the result. (2.0 style)
4464 'aclname' is the name of a defined ACL.
4466 NP: Using 'none' as the byte value here will override any quick_abort settings
4467 that may otherwise apply to the range request. The range request will
4468 be fully fetched from start to finish regardless of the client
4469 actions. This affects bandwidth usage.
4472 NAME: minimum_expiry_time
4475 LOC: Config.minimum_expiry_time
4478 The minimum caching time according to (Expires - Date)
4479 Headers Squid honors if the object can't be revalidated
4480 defaults to 60 seconds. In reverse proxy environments it
4481 might be desirable to honor shorter object lifetimes. It
4482 is most likely better to make your server return a
4483 meaningful Last-Modified header however. In ESI environments
4484 where page fragments often have short lifetimes, this will
4485 often be best set to 0.
4488 NAME: store_avg_object_size
4492 LOC: Config.Store.avgObjectSize
4494 Average object size, used to estimate number of objects your
4495 cache can hold. The default is 13 KB.
4498 NAME: store_objects_per_bucket
4501 LOC: Config.Store.objectsPerBucket
4503 Target number of objects per bucket in the store hash table.
4504 Lowering this value increases the total number of buckets and
4505 also the storage maintenance rate. The default is 20.
4510 -----------------------------------------------------------------------------
4513 NAME: request_header_max_size
4517 LOC: Config.maxRequestHeaderSize
4519 This specifies the maximum size for HTTP headers in a request.
4520 Request headers are usually relatively small (about 512 bytes).
4521 Placing a limit on the request header size will catch certain
4522 bugs (for example with persistent connections) and possibly
4523 buffer-overflow or denial-of-service attacks.
4526 NAME: reply_header_max_size
4530 LOC: Config.maxReplyHeaderSize
4532 This specifies the maximum size for HTTP headers in a reply.
4533 Reply headers are usually relatively small (about 512 bytes).
4534 Placing a limit on the reply header size will catch certain
4535 bugs (for example with persistent connections) and possibly
4536 buffer-overflow or denial-of-service attacks.
4539 NAME: request_body_max_size
4543 LOC: Config.maxRequestBodySize
4545 This specifies the maximum size for an HTTP request body.
4546 In other words, the maximum size of a PUT/POST request.
4547 A user who attempts to send a request with a body larger
4548 than this limit receives an "Invalid Request" error message.
4549 If you set this parameter to a zero (the default), there will
4550 be no limit imposed.
4553 NAME: client_request_buffer_max_size
4557 LOC: Config.maxRequestBufferSize
4559 This specifies the maximum buffer size of a client request.
4560 It prevents squid eating too much memory when somebody uploads
4564 NAME: chunked_request_body_max_size
4568 LOC: Config.maxChunkedRequestBodySize
4570 A broken or confused HTTP/1.1 client may send a chunked HTTP
4571 request to Squid. Squid does not have full support for that
4572 feature yet. To cope with such requests, Squid buffers the
4573 entire request and then dechunks request body to create a
4574 plain HTTP/1.0 request with a known content length. The plain
4575 request is then used by the rest of Squid code as usual.
4577 The option value specifies the maximum size of the buffer used
4578 to hold the request before the conversion. If the chunked
4579 request size exceeds the specified limit, the conversion
4580 fails, and the client receives an "unsupported request" error,
4581 as if dechunking was disabled.
4583 Dechunking is enabled by default. To disable conversion of
4584 chunked requests, set the maximum to zero.
4586 Request dechunking feature and this option in particular are a
4587 temporary hack. When chunking requests and responses are fully
4588 supported, there will be no need to buffer a chunked request.
4592 IFDEF: USE_HTTP_VIOLATIONS
4595 LOC: Config.accessList.brokenPosts
4597 A list of ACL elements which, if matched, causes Squid to send
4598 an extra CRLF pair after the body of a PUT/POST request.
4600 Some HTTP servers has broken implementations of PUT/POST,
4601 and rely on an extra CRLF pair sent by some WWW clients.
4603 Quote from RFC2616 section 4.1 on this matter:
4605 Note: certain buggy HTTP/1.0 client implementations generate an
4606 extra CRLF's after a POST request. To restate what is explicitly
4607 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
4608 a request with an extra CRLF.
4610 This clause only supports fast acl types.
4611 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4614 acl buggy_server url_regex ^http://....
4615 broken_posts allow buggy_server
4618 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
4621 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
4623 LOC: Adaptation::Config::use_indirect_client
4625 Controls whether the indirect client IP address (instead of the direct
4626 client IP address) is passed to adaptation services.
4628 See also: follow_x_forwarded_for adaptation_send_client_ip
4632 IFDEF: USE_HTTP_VIOLATIONS
4636 LOC: Config.onoff.via
4638 If set (default), Squid will include a Via header in requests and
4639 replies as required by RFC2616.
4645 LOC: Config.onoff.ie_refresh
4648 Microsoft Internet Explorer up until version 5.5 Service
4649 Pack 1 has an issue with transparent proxies, wherein it
4650 is impossible to force a refresh. Turning this on provides
4651 a partial fix to the problem, by causing all IMS-REFRESH
4652 requests from older IE versions to check the origin server
4653 for fresh content. This reduces hit ratio by some amount
4654 (~10% in my experience), but allows users to actually get
4655 fresh content when they want it. Note because Squid
4656 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
4657 of 5.5 is unchanged from old versions of Squid (i.e. a
4658 forced refresh is impossible). Newer versions of IE will,
4659 hopefully, continue to have the new behavior and will be
4660 handled based on that assumption. This option defaults to
4661 the old Squid behavior, which is better for hit ratios but
4662 worse for clients using IE, if they need to be able to
4663 force fresh content.
4666 NAME: vary_ignore_expire
4669 LOC: Config.onoff.vary_ignore_expire
4672 Many HTTP servers supporting Vary gives such objects
4673 immediate expiry time with no cache-control header
4674 when requested by a HTTP/1.0 client. This option
4675 enables Squid to ignore such expiry times until
4676 HTTP/1.1 is fully implemented.
4678 WARNING: If turned on this may eventually cause some
4679 varying objects not intended for caching to get cached.
4682 NAME: request_entities
4684 LOC: Config.onoff.request_entities
4687 Squid defaults to deny GET and HEAD requests with request entities,
4688 as the meaning of such requests are undefined in the HTTP standard
4689 even if not explicitly forbidden.
4691 Set this directive to on if you have clients which insists
4692 on sending request entities in GET or HEAD requests. But be warned
4693 that there is server software (both proxies and web servers) which
4694 can fail to properly process this kind of request which may make you
4695 vulnerable to cache pollution attacks if enabled.
4698 NAME: request_header_access
4699 IFDEF: USE_HTTP_VIOLATIONS
4700 TYPE: http_header_access
4701 LOC: Config.request_header_access
4704 Usage: request_header_access header_name allow|deny [!]aclname ...
4706 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4707 this feature could make you liable for problems which it
4710 This option replaces the old 'anonymize_headers' and the
4711 older 'http_anonymizer' option with something that is much
4712 more configurable. A list of ACLs for each header name allows
4713 removal of specific header fields under specific conditions.
4715 This option only applies to outgoing HTTP request headers (i.e.,
4716 headers sent by Squid to the next HTTP hop such as a cache peer
4717 or an origin server). The option has no effect during cache hit
4718 detection. The equivalent adaptation vectoring point in ICAP
4719 terminology is post-cache REQMOD.
4721 The option is applied to individual outgoing request header
4722 fields. For each request header field F, Squid uses the first
4723 qualifying sets of request_header_access rules:
4725 1. Rules with header_name equal to F's name.
4726 2. Rules with header_name 'Other', provided F's name is not
4727 on the hard-coded list of commonly used HTTP header names.
4728 3. Rules with header_name 'All'.
4730 Within that qualifying rule set, rule ACLs are checked as usual.
4731 If ACLs of an "allow" rule match, the header field is allowed to
4732 go through as is. If ACLs of a "deny" rule match, the header is
4733 removed and request_header_replace is then checked to identify
4734 if the removed header has a replacement. If no rules within the
4735 set have matching ACLs, the header field is left as is.
4737 For example, to achieve the same behavior as the old
4738 'http_anonymizer standard' option, you should use:
4740 request_header_access From deny all
4741 request_header_access Referer deny all
4742 request_header_access Server deny all
4743 request_header_access User-Agent deny all
4744 request_header_access WWW-Authenticate deny all
4745 request_header_access Link deny all
4747 Or, to reproduce the old 'http_anonymizer paranoid' feature
4750 request_header_access Allow allow all
4751 request_header_access Authorization allow all
4752 request_header_access WWW-Authenticate allow all
4753 request_header_access Proxy-Authorization allow all
4754 request_header_access Proxy-Authenticate allow all
4755 request_header_access Cache-Control allow all
4756 request_header_access Content-Encoding allow all
4757 request_header_access Content-Length allow all
4758 request_header_access Content-Type allow all
4759 request_header_access Date allow all
4760 request_header_access Expires allow all
4761 request_header_access Host allow all
4762 request_header_access If-Modified-Since allow all
4763 request_header_access Last-Modified allow all
4764 request_header_access Location allow all
4765 request_header_access Pragma allow all
4766 request_header_access Accept allow all
4767 request_header_access Accept-Charset allow all
4768 request_header_access Accept-Encoding allow all
4769 request_header_access Accept-Language allow all
4770 request_header_access Content-Language allow all
4771 request_header_access Mime-Version allow all
4772 request_header_access Retry-After allow all
4773 request_header_access Title allow all
4774 request_header_access Connection allow all
4775 request_header_access All deny all
4777 although many of those are HTTP reply headers, and so should be
4778 controlled with the reply_header_access directive.
4780 By default, all headers are allowed (no anonymizing is
4784 NAME: reply_header_access
4785 IFDEF: USE_HTTP_VIOLATIONS
4786 TYPE: http_header_access
4787 LOC: Config.reply_header_access
4790 Usage: reply_header_access header_name allow|deny [!]aclname ...
4792 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4793 this feature could make you liable for problems which it
4796 This option only applies to reply headers, i.e., from the
4797 server to the client.
4799 This is the same as request_header_access, but in the other
4800 direction. Please see request_header_access for detailed
4803 For example, to achieve the same behavior as the old
4804 'http_anonymizer standard' option, you should use:
4806 reply_header_access From deny all
4807 reply_header_access Referer deny all
4808 reply_header_access Server deny all
4809 reply_header_access User-Agent deny all
4810 reply_header_access WWW-Authenticate deny all
4811 reply_header_access Link deny all
4813 Or, to reproduce the old 'http_anonymizer paranoid' feature
4816 reply_header_access Allow allow all
4817 reply_header_access Authorization allow all
4818 reply_header_access WWW-Authenticate allow all
4819 reply_header_access Proxy-Authorization allow all
4820 reply_header_access Proxy-Authenticate allow all
4821 reply_header_access Cache-Control allow all
4822 reply_header_access Content-Encoding allow all
4823 reply_header_access Content-Length allow all
4824 reply_header_access Content-Type allow all
4825 reply_header_access Date allow all
4826 reply_header_access Expires allow all
4827 reply_header_access Host allow all
4828 reply_header_access If-Modified-Since allow all
4829 reply_header_access Last-Modified allow all
4830 reply_header_access Location allow all
4831 reply_header_access Pragma allow all
4832 reply_header_access Accept allow all
4833 reply_header_access Accept-Charset allow all
4834 reply_header_access Accept-Encoding allow all
4835 reply_header_access Accept-Language allow all
4836 reply_header_access Content-Language allow all
4837 reply_header_access Mime-Version allow all
4838 reply_header_access Retry-After allow all
4839 reply_header_access Title allow all
4840 reply_header_access Connection allow all
4841 reply_header_access All deny all
4843 although the HTTP request headers won't be usefully controlled
4844 by this directive -- see request_header_access for details.
4846 By default, all headers are allowed (no anonymizing is
4850 NAME: request_header_replace header_replace
4851 IFDEF: USE_HTTP_VIOLATIONS
4852 TYPE: http_header_replace
4853 LOC: Config.request_header_access
4856 Usage: request_header_replace header_name message
4857 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
4859 This option allows you to change the contents of headers
4860 denied with request_header_access above, by replacing them
4861 with some fixed string. This replaces the old fake_user_agent
4864 This only applies to request headers, not reply headers.
4866 By default, headers are removed if denied.
4869 NAME: reply_header_replace
4870 IFDEF: USE_HTTP_VIOLATIONS
4871 TYPE: http_header_replace
4872 LOC: Config.reply_header_access
4875 Usage: reply_header_replace header_name message
4876 Example: reply_header_replace Server Foo/1.0
4878 This option allows you to change the contents of headers
4879 denied with reply_header_access above, by replacing them
4880 with some fixed string.
4882 This only applies to reply headers, not request headers.
4884 By default, headers are removed if denied.
4887 NAME: request_header_add
4888 TYPE: HeaderWithAclList
4889 LOC: Config.request_header_add
4892 Usage: request_header_add field-name field-value acl1 [acl2] ...
4893 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
4895 This option adds header fields to outgoing HTTP requests (i.e.,
4896 request headers sent by Squid to the next HTTP hop such as a
4897 cache peer or an origin server). The option has no effect during
4898 cache hit detection. The equivalent adaptation vectoring point
4899 in ICAP terminology is post-cache REQMOD.
4901 Field-name is a token specifying an HTTP header name. If a
4902 standard HTTP header name is used, Squid does not check whether
4903 the new header conflicts with any existing headers or violates
4904 HTTP rules. If the request to be modified already contains a
4905 field with the same name, the old field is preserved but the
4906 header field values are not merged.
4908 Field-value is either a token or a quoted string. If quoted
4909 string format is used, then the surrounding quotes are removed
4910 while escape sequences and %macros are processed.
4912 In theory, all of the logformat codes can be used as %macros.
4913 However, unlike logging (which happens at the very end of
4914 transaction lifetime), the transaction may not yet have enough
4915 information to expand a macro when the new header value is needed.
4916 And some information may already be available to Squid but not yet
4917 committed where the macro expansion code can access it (report
4918 such instances!). The macro will be expanded into a single dash
4919 ('-') in such cases. Not all macros have been tested.
4921 One or more Squid ACLs may be specified to restrict header
4922 injection to matching requests. As always in squid.conf, all
4923 ACLs in an option ACL list must be satisfied for the insertion
4924 to happen. The request_header_add option supports fast ACLs
4933 This option used to log custom information about the master
4934 transaction. For example, an admin may configure Squid to log
4935 which "user group" the transaction belongs to, where "user group"
4936 will be determined based on a set of ACLs and not [just]
4937 authentication information.
4938 Values of key/value pairs can be logged using %{key}note macros:
4940 note key value acl ...
4941 logformat myFormat ... %{key}note ...
4944 NAME: relaxed_header_parser
4945 COMMENT: on|off|warn
4947 LOC: Config.onoff.relaxed_header_parser
4950 In the default "on" setting Squid accepts certain forms
4951 of non-compliant HTTP messages where it is unambiguous
4952 what the sending application intended even if the message
4953 is not correctly formatted. The messages is then normalized
4954 to the correct form when forwarded by Squid.
4956 If set to "warn" then a warning will be emitted in cache.log
4957 each time such HTTP error is encountered.
4959 If set to "off" then such HTTP errors will cause the request
4960 or response to be rejected.
4965 -----------------------------------------------------------------------------
4968 NAME: forward_timeout
4971 LOC: Config.Timeout.forward
4974 This parameter specifies how long Squid should at most attempt in
4975 finding a forwarding path for the request before giving up.
4978 NAME: connect_timeout
4981 LOC: Config.Timeout.connect
4984 This parameter specifies how long to wait for the TCP connect to
4985 the requested server or peer to complete before Squid should
4986 attempt to find another path where to forward the request.
4989 NAME: peer_connect_timeout
4992 LOC: Config.Timeout.peer_connect
4995 This parameter specifies how long to wait for a pending TCP
4996 connection to a peer cache. The default is 30 seconds. You
4997 may also set different timeout values for individual neighbors
4998 with the 'connect-timeout' option on a 'cache_peer' line.
5004 LOC: Config.Timeout.read
5007 The read_timeout is applied on server-side connections. After
5008 each successful read(), the timeout will be extended by this
5009 amount. If no data is read again after this amount of time,
5010 the request is aborted and logged with ERR_READ_TIMEOUT. The
5011 default is 15 minutes.
5017 LOC: Config.Timeout.write
5020 This timeout is tracked for all connections that have data
5021 available for writing and are waiting for the socket to become
5022 ready. After each successful write, the timeout is extended by
5023 the configured amount. If Squid has data to write but the
5024 connection is not ready for the configured duration, the
5025 transaction associated with the connection is terminated. The
5026 default is 15 minutes.
5029 NAME: request_timeout
5031 LOC: Config.Timeout.request
5034 How long to wait for complete HTTP request headers after initial
5035 connection establishment.
5038 NAME: client_idle_pconn_timeout persistent_request_timeout
5040 LOC: Config.Timeout.clientIdlePconn
5043 How long to wait for the next HTTP request on a persistent
5044 client connection after the previous request completes.
5047 NAME: client_lifetime
5050 LOC: Config.Timeout.lifetime
5053 The maximum amount of time a client (browser) is allowed to
5054 remain connected to the cache process. This protects the Cache
5055 from having a lot of sockets (and hence file descriptors) tied up
5056 in a CLOSE_WAIT state from remote clients that go away without
5057 properly shutting down (either because of a network failure or
5058 because of a poor client implementation). The default is one
5061 NOTE: The default value is intended to be much larger than any
5062 client would ever need to be connected to your cache. You
5063 should probably change client_lifetime only as a last resort.
5064 If you seem to have many client connections tying up
5065 filedescriptors, we recommend first tuning the read_timeout,
5066 request_timeout, persistent_request_timeout and quick_abort values.
5069 NAME: half_closed_clients
5071 LOC: Config.onoff.half_closed_clients
5074 Some clients may shutdown the sending side of their TCP
5075 connections, while leaving their receiving sides open. Sometimes,
5076 Squid can not tell the difference between a half-closed and a
5077 fully-closed TCP connection.
5079 By default, Squid will immediately close client connections when
5080 read(2) returns "no more data to read."
5082 Change this option to 'on' and Squid will keep open connections
5083 until a read(2) or write(2) on the socket returns an error.
5084 This may show some benefits for reverse proxies. But if not
5085 it is recommended to leave OFF.
5088 NAME: server_idle_pconn_timeout pconn_timeout
5090 LOC: Config.Timeout.serverIdlePconn
5093 Timeout for idle persistent connections to servers and other
5100 LOC: Ident::TheConfig.timeout
5103 Maximum time to wait for IDENT lookups to complete.
5105 If this is too high, and you enabled IDENT lookups from untrusted
5106 users, you might be susceptible to denial-of-service by having
5107 many ident requests going at once.
5110 NAME: shutdown_lifetime
5113 LOC: Config.shutdownLifetime
5116 When SIGTERM or SIGHUP is received, the cache is put into
5117 "shutdown pending" mode until all active sockets are closed.
5118 This value is the lifetime to set for all open descriptors
5119 during shutdown mode. Any active clients after this many
5120 seconds will receive a 'timeout' message.
5124 ADMINISTRATIVE PARAMETERS
5125 -----------------------------------------------------------------------------
5131 LOC: Config.adminEmail
5133 Email-address of local cache manager who will receive
5134 mail if the cache dies. The default is "webmaster."
5140 LOC: Config.EmailFrom
5142 From: email-address for mail sent when the cache dies.
5143 The default is to use 'appname@unique_hostname'.
5144 Default appname value is "squid", can be changed into
5145 src/globals.h before building squid.
5151 LOC: Config.EmailProgram
5153 Email program used to send mail if the cache dies.
5154 The default is "mail". The specified program must comply
5155 with the standard Unix mail syntax:
5156 mail-program recipient < mailfile
5158 Optional command line options can be specified.
5161 NAME: cache_effective_user
5163 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
5164 LOC: Config.effectiveUser
5166 If you start Squid as root, it will change its effective/real
5167 UID/GID to the user specified below. The default is to change
5168 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
5169 see also; cache_effective_group
5172 NAME: cache_effective_group
5175 LOC: Config.effectiveGroup
5177 Squid sets the GID to the effective user's default group ID
5178 (taken from the password file) and supplementary group list
5179 from the groups membership.
5181 If you want Squid to run with a specific GID regardless of
5182 the group memberships of the effective user then set this
5183 to the group (or GID) you want Squid to run as. When set
5184 all other group privileges of the effective user are ignored
5185 and only this GID is effective. If Squid is not started as
5186 root the user starting Squid MUST be member of the specified
5189 This option is not recommended by the Squid Team.
5190 Our preference is for administrators to configure a secure
5191 user account for squid with UID/GID matching system policies.
5194 NAME: httpd_suppress_version_string
5198 LOC: Config.onoff.httpd_suppress_version_string
5200 Suppress Squid version string info in HTTP headers and HTML error pages.
5203 NAME: visible_hostname
5205 LOC: Config.visibleHostname
5208 If you want to present a special hostname in error messages, etc,
5209 define this. Otherwise, the return value of gethostname()
5210 will be used. If you have multiple caches in a cluster and
5211 get errors about IP-forwarding you must set them to have individual
5212 names with this setting.
5215 NAME: unique_hostname
5217 LOC: Config.uniqueHostname
5220 If you want to have multiple machines with the same
5221 'visible_hostname' you must give each machine a different
5222 'unique_hostname' so forwarding loops can be detected.
5225 NAME: hostname_aliases
5227 LOC: Config.hostnameAliases
5230 A list of other DNS names your cache has.
5238 Minimum umask which should be enforced while the proxy
5239 is running, in addition to the umask set at startup.
5241 For a traditional octal representation of umasks, start
5246 OPTIONS FOR THE CACHE REGISTRATION SERVICE
5247 -----------------------------------------------------------------------------
5249 This section contains parameters for the (optional) cache
5250 announcement service. This service is provided to help
5251 cache administrators locate one another in order to join or
5252 create cache hierarchies.
5254 An 'announcement' message is sent (via UDP) to the registration
5255 service by Squid. By default, the announcement message is NOT
5256 SENT unless you enable it with 'announce_period' below.
5258 The announcement message includes your hostname, plus the
5259 following information from this configuration file:
5265 All current information is processed regularly and made
5266 available on the Web at http://www.ircache.net/Cache/Tracker/.
5269 NAME: announce_period
5271 LOC: Config.Announce.period
5274 This is how frequently to send cache announcements. The
5275 default is `0' which disables sending the announcement
5278 To enable announcing your cache, just set an announce period.
5281 announce_period 1 day
5286 DEFAULT: tracker.ircache.net
5287 LOC: Config.Announce.host
5293 LOC: Config.Announce.file
5299 LOC: Config.Announce.port
5301 announce_host and announce_port set the hostname and port
5302 number where the registration message will be sent.
5304 Hostname will default to 'tracker.ircache.net' and port will
5305 default default to 3131. If the 'filename' argument is given,
5306 the contents of that file will be included in the announce
5311 HTTPD-ACCELERATOR OPTIONS
5312 -----------------------------------------------------------------------------
5315 NAME: httpd_accel_surrogate_id
5318 LOC: Config.Accel.surrogate_id
5320 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
5321 need an identification token to allow control targeting. Because
5322 a farm of surrogates may all perform the same tasks, they may share
5323 an identification token.
5325 The default ID is the visible_hostname
5328 NAME: http_accel_surrogate_remote
5332 LOC: Config.onoff.surrogate_is_remote
5334 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
5335 Set this to on to have squid behave as a remote surrogate.
5339 IFDEF: USE_SQUID_ESI
5340 COMMENT: libxml2|expat|custom
5342 LOC: ESIParser::Type
5345 ESI markup is not strictly XML compatible. The custom ESI parser
5346 will give higher performance, but cannot handle non ASCII character
5351 DELAY POOL PARAMETERS
5352 -----------------------------------------------------------------------------
5356 TYPE: delay_pool_count
5358 IFDEF: USE_DELAY_POOLS
5361 This represents the number of delay pools to be used. For example,
5362 if you have one class 2 delay pool and one class 3 delays pool, you
5363 have a total of 2 delay pools.
5367 TYPE: delay_pool_class
5369 IFDEF: USE_DELAY_POOLS
5372 This defines the class of each delay pool. There must be exactly one
5373 delay_class line for each delay pool. For example, to define two
5374 delay pools, one of class 2 and one of class 3, the settings above
5378 delay_pools 4 # 4 delay pools
5379 delay_class 1 2 # pool 1 is a class 2 pool
5380 delay_class 2 3 # pool 2 is a class 3 pool
5381 delay_class 3 4 # pool 3 is a class 4 pool
5382 delay_class 4 5 # pool 4 is a class 5 pool
5384 The delay pool classes are:
5386 class 1 Everything is limited by a single aggregate
5389 class 2 Everything is limited by a single aggregate
5390 bucket as well as an "individual" bucket chosen
5391 from bits 25 through 32 of the IPv4 address.
5393 class 3 Everything is limited by a single aggregate
5394 bucket as well as a "network" bucket chosen
5395 from bits 17 through 24 of the IP address and a
5396 "individual" bucket chosen from bits 17 through
5397 32 of the IPv4 address.
5399 class 4 Everything in a class 3 delay pool, with an
5400 additional limit on a per user basis. This
5401 only takes effect if the username is established
5402 in advance - by forcing authentication in your
5405 class 5 Requests are grouped according their tag (see
5406 external_acl's tag= reply).
5409 Each pool also requires a delay_parameters directive to configure the pool size
5410 and speed limits used whenever the pool is applied to a request. Along with
5411 a set of delay_access directives to determine when it is used.
5413 NOTE: If an IP address is a.b.c.d
5414 -> bits 25 through 32 are "d"
5415 -> bits 17 through 24 are "c"
5416 -> bits 17 through 32 are "c * 256 + d"
5418 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
5419 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
5423 TYPE: delay_pool_access
5425 IFDEF: USE_DELAY_POOLS
5428 This is used to determine which delay pool a request falls into.
5430 delay_access is sorted per pool and the matching starts with pool 1,
5431 then pool 2, ..., and finally pool N. The first delay pool where the
5432 request is allowed is selected for the request. If it does not allow
5433 the request to any pool then the request is not delayed (default).
5435 For example, if you want some_big_clients in delay
5436 pool 1 and lotsa_little_clients in delay pool 2:
5439 delay_access 1 allow some_big_clients
5440 delay_access 1 deny all
5441 delay_access 2 allow lotsa_little_clients
5442 delay_access 2 deny all
5443 delay_access 3 allow authenticated_clients
5446 NAME: delay_parameters
5447 TYPE: delay_pool_rates
5449 IFDEF: USE_DELAY_POOLS
5452 This defines the parameters for a delay pool. Each delay pool has
5453 a number of "buckets" associated with it, as explained in the
5454 description of delay_class.
5456 For a class 1 delay pool, the syntax is:
5458 delay_parameters pool aggregate
5460 For a class 2 delay pool:
5462 delay_parameters pool aggregate individual
5464 For a class 3 delay pool:
5466 delay_parameters pool aggregate network individual
5468 For a class 4 delay pool:
5470 delay_parameters pool aggregate network individual user
5472 For a class 5 delay pool:
5474 delay_parameters pool tagrate
5476 The option variables are:
5478 pool a pool number - ie, a number between 1 and the
5479 number specified in delay_pools as used in
5482 aggregate the speed limit parameters for the aggregate bucket
5485 individual the speed limit parameters for the individual
5486 buckets (class 2, 3).
5488 network the speed limit parameters for the network buckets
5491 user the speed limit parameters for the user buckets
5494 tagrate the speed limit parameters for the tag buckets
5497 A pair of delay parameters is written restore/maximum, where restore is
5498 the number of bytes (not bits - modem and network speeds are usually
5499 quoted in bits) per second placed into the bucket, and maximum is the
5500 maximum number of bytes which can be in the bucket at any time.
5502 There must be one delay_parameters line for each delay pool.
5505 For example, if delay pool number 1 is a class 2 delay pool as in the
5506 above example, and is being used to strictly limit each host to 64Kbit/sec
5507 (plus overheads), with no overall limit, the line is:
5509 delay_parameters 1 -1/-1 8000/8000
5511 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
5513 Note that the figure -1 is used to represent "unlimited".
5516 And, if delay pool number 2 is a class 3 delay pool as in the above
5517 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
5518 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
5519 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
5520 to permit a decent web page to be downloaded at a decent speed
5521 (if the network is not being limited due to overuse) but slow down
5522 large downloads more significantly:
5524 delay_parameters 2 32000/32000 8000/8000 600/8000
5526 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
5527 8 x 8000 KByte/sec -> 64Kbit/sec.
5528 8 x 600 Byte/sec -> 4800bit/sec.
5531 Finally, for a class 4 delay pool as in the example - each user will
5532 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
5534 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
5537 NAME: delay_initial_bucket_level
5538 COMMENT: (percent, 0-100)
5541 IFDEF: USE_DELAY_POOLS
5542 LOC: Config.Delay.initial
5544 The initial bucket percentage is used to determine how much is put
5545 in each bucket when squid starts, is reconfigured, or first notices
5546 a host accessing it (in class 2 and class 3, individual hosts and
5547 networks only have buckets associated with them once they have been
5552 CLIENT DELAY POOL PARAMETERS
5553 -----------------------------------------------------------------------------
5556 NAME: client_delay_pools
5557 TYPE: client_delay_pool_count
5559 IFDEF: USE_DELAY_POOLS
5560 LOC: Config.ClientDelay
5562 This option specifies the number of client delay pools used. It must
5563 preceed other client_delay_* options.
5566 client_delay_pools 2
5569 NAME: client_delay_initial_bucket_level
5570 COMMENT: (percent, 0-no_limit)
5573 IFDEF: USE_DELAY_POOLS
5574 LOC: Config.ClientDelay.initial
5576 This option determines the initial bucket size as a percentage of
5577 max_bucket_size from client_delay_parameters. Buckets are created
5578 at the time of the "first" connection from the matching IP. Idle
5579 buckets are periodically deleted up.
5581 You can specify more than 100 percent but note that such "oversized"
5582 buckets are not refilled until their size goes down to max_bucket_size
5583 from client_delay_parameters.
5586 client_delay_initial_bucket_level 50
5589 NAME: client_delay_parameters
5590 TYPE: client_delay_pool_rates
5592 IFDEF: USE_DELAY_POOLS
5593 LOC: Config.ClientDelay
5596 This option configures client-side bandwidth limits using the
5599 client_delay_parameters pool speed_limit max_bucket_size
5601 pool is an integer ID used for client_delay_access matching.
5603 speed_limit is bytes added to the bucket per second.
5605 max_bucket_size is the maximum size of a bucket, enforced after any
5606 speed_limit additions.
5608 Please see the delay_parameters option for more information and
5612 client_delay_parameters 1 1024 2048
5613 client_delay_parameters 2 51200 16384
5616 NAME: client_delay_access
5617 TYPE: client_delay_pool_access
5619 IFDEF: USE_DELAY_POOLS
5620 LOC: Config.ClientDelay
5623 This option determines the client-side delay pool for the
5626 client_delay_access pool_ID allow|deny acl_name
5628 All client_delay_access options are checked in their pool ID
5629 order, starting with pool 1. The first checked pool with allowed
5630 request is selected for the request. If no ACL matches or there
5631 are no client_delay_access options, the request bandwidth is not
5634 The ACL-selected pool is then used to find the
5635 client_delay_parameters for the request. Client-side pools are
5636 not used to aggregate clients. Clients are always aggregated
5637 based on their source IP addresses (one bucket per source IP).
5639 Please see delay_access for more examples.
5642 client_delay_access 1 allow low_rate_network
5643 client_delay_access 2 allow vips_network
5647 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
5648 -----------------------------------------------------------------------------
5653 LOC: Config.Wccp.router
5657 Use this option to define your WCCP ``home'' router for
5660 wccp_router supports a single WCCP(v1) router
5662 wccp2_router supports multiple WCCPv2 routers
5664 only one of the two may be used at the same time and defines
5665 which version of WCCP to use.
5669 TYPE: IpAddress_list
5670 LOC: Config.Wccp2.router
5674 Use this option to define your WCCP ``home'' router for
5677 wccp_router supports a single WCCP(v1) router
5679 wccp2_router supports multiple WCCPv2 routers
5681 only one of the two may be used at the same time and defines
5682 which version of WCCP to use.
5687 LOC: Config.Wccp.version
5691 This directive is only relevant if you need to set up WCCP(v1)
5692 to some very old and end-of-life Cisco routers. In all other
5693 setups it must be left unset or at the default setting.
5694 It defines an internal version in the WCCP(v1) protocol,
5695 with version 4 being the officially documented protocol.
5697 According to some users, Cisco IOS 11.2 and earlier only
5698 support WCCP version 3. If you're using that or an earlier
5699 version of IOS, you may need to change this value to 3, otherwise
5700 do not specify this parameter.
5703 NAME: wccp2_rebuild_wait
5705 LOC: Config.Wccp2.rebuildwait
5709 If this is enabled Squid will wait for the cache dir rebuild to finish
5710 before sending the first wccp2 HereIAm packet
5713 NAME: wccp2_forwarding_method
5715 LOC: Config.Wccp2.forwarding_method
5719 WCCP2 allows the setting of forwarding methods between the
5720 router/switch and the cache. Valid values are as follows:
5722 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5723 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5725 Currently (as of IOS 12.4) cisco routers only support GRE.
5726 Cisco switches only support the L2 redirect assignment method.
5729 NAME: wccp2_return_method
5731 LOC: Config.Wccp2.return_method
5735 WCCP2 allows the setting of return methods between the
5736 router/switch and the cache for packets that the cache
5737 decides not to handle. Valid values are as follows:
5739 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5740 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5742 Currently (as of IOS 12.4) cisco routers only support GRE.
5743 Cisco switches only support the L2 redirect assignment.
5745 If the "ip wccp redirect exclude in" command has been
5746 enabled on the cache interface, then it is still safe for
5747 the proxy server to use a l2 redirect method even if this
5748 option is set to GRE.
5751 NAME: wccp2_assignment_method
5753 LOC: Config.Wccp2.assignment_method
5757 WCCP2 allows the setting of methods to assign the WCCP hash
5758 Valid values are as follows:
5760 hash - Hash assignment
5761 mask - Mask assignment
5763 As a general rule, cisco routers support the hash assignment method
5764 and cisco switches support the mask assignment method.
5769 LOC: Config.Wccp2.info
5770 DEFAULT_IF_NONE: standard 0
5773 WCCP2 allows for multiple traffic services. There are two
5774 types: "standard" and "dynamic". The standard type defines
5775 one service id - http (id 0). The dynamic service ids can be from
5776 51 to 255 inclusive. In order to use a dynamic service id
5777 one must define the type of traffic to be redirected; this is done
5778 using the wccp2_service_info option.
5780 The "standard" type does not require a wccp2_service_info option,
5781 just specifying the service id will suffice.
5783 MD5 service authentication can be enabled by adding
5784 "password=<password>" to the end of this service declaration.
5788 wccp2_service standard 0 # for the 'web-cache' standard service
5789 wccp2_service dynamic 80 # a dynamic service type which will be
5790 # fleshed out with subsequent options.
5791 wccp2_service standard 0 password=foo
5794 NAME: wccp2_service_info
5795 TYPE: wccp2_service_info
5796 LOC: Config.Wccp2.info
5800 Dynamic WCCPv2 services require further information to define the
5801 traffic you wish to have diverted.
5805 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
5806 priority=<priority> ports=<port>,<port>..
5808 The relevant WCCPv2 flags:
5809 + src_ip_hash, dst_ip_hash
5810 + source_port_hash, dst_port_hash
5811 + src_ip_alt_hash, dst_ip_alt_hash
5812 + src_port_alt_hash, dst_port_alt_hash
5815 The port list can be one to eight entries.
5819 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
5820 priority=240 ports=80
5822 Note: the service id must have been defined by a previous
5823 'wccp2_service dynamic <id>' entry.
5828 LOC: Config.Wccp2.weight
5832 Each cache server gets assigned a set of the destination
5833 hash proportional to their weight.
5838 LOC: Config.Wccp.address
5845 LOC: Config.Wccp2.address
5849 Use this option if you require WCCP to use a specific
5852 The default behavior is to not bind to any specific address.
5856 PERSISTENT CONNECTION HANDLING
5857 -----------------------------------------------------------------------------
5859 Also see "pconn_timeout" in the TIMEOUTS section
5862 NAME: client_persistent_connections
5864 LOC: Config.onoff.client_pconns
5868 NAME: server_persistent_connections
5870 LOC: Config.onoff.server_pconns
5873 Persistent connection support for clients and servers. By
5874 default, Squid uses persistent connections (when allowed)
5875 with its clients and servers. You can use these options to
5876 disable persistent connections with clients and/or servers.
5879 NAME: persistent_connection_after_error
5881 LOC: Config.onoff.error_pconns
5884 With this directive the use of persistent connections after
5885 HTTP errors can be disabled. Useful if you have clients
5886 who fail to handle errors on persistent connections proper.
5889 NAME: detect_broken_pconn
5891 LOC: Config.onoff.detect_broken_server_pconns
5894 Some servers have been found to incorrectly signal the use
5895 of HTTP/1.0 persistent connections even on replies not
5896 compatible, causing significant delays. This server problem
5897 has mostly been seen on redirects.
5899 By enabling this directive Squid attempts to detect such
5900 broken replies and automatically assume the reply is finished
5901 after 10 seconds timeout.
5905 CACHE DIGEST OPTIONS
5906 -----------------------------------------------------------------------------
5909 NAME: digest_generation
5910 IFDEF: USE_CACHE_DIGESTS
5912 LOC: Config.onoff.digest_generation
5915 This controls whether the server will generate a Cache Digest
5916 of its contents. By default, Cache Digest generation is
5917 enabled if Squid is compiled with --enable-cache-digests defined.
5920 NAME: digest_bits_per_entry
5921 IFDEF: USE_CACHE_DIGESTS
5923 LOC: Config.digest.bits_per_entry
5926 This is the number of bits of the server's Cache Digest which
5927 will be associated with the Digest entry for a given HTTP
5928 Method and URL (public key) combination. The default is 5.
5931 NAME: digest_rebuild_period
5932 IFDEF: USE_CACHE_DIGESTS
5935 LOC: Config.digest.rebuild_period
5938 This is the wait time between Cache Digest rebuilds.
5941 NAME: digest_rewrite_period
5943 IFDEF: USE_CACHE_DIGESTS
5945 LOC: Config.digest.rewrite_period
5948 This is the wait time between Cache Digest writes to
5952 NAME: digest_swapout_chunk_size
5955 IFDEF: USE_CACHE_DIGESTS
5956 LOC: Config.digest.swapout_chunk_size
5959 This is the number of bytes of the Cache Digest to write to
5960 disk at a time. It defaults to 4096 bytes (4KB), the Squid
5964 NAME: digest_rebuild_chunk_percentage
5965 COMMENT: (percent, 0-100)
5966 IFDEF: USE_CACHE_DIGESTS
5968 LOC: Config.digest.rebuild_chunk_percentage
5971 This is the percentage of the Cache Digest to be scanned at a
5972 time. By default it is set to 10% of the Cache Digest.
5977 -----------------------------------------------------------------------------
5982 LOC: Config.Port.snmp
5986 The port number where Squid listens for SNMP requests. To enable
5987 SNMP support set this to a suitable port number. Port number
5988 3401 is often used for the Squid SNMP agent. By default it's
5989 set to "0" (disabled)
5997 LOC: Config.accessList.snmp
5998 DEFAULT_IF_NONE: deny all
6001 Allowing or denying access to the SNMP port.
6003 All access to the agent is denied by default.
6006 snmp_access allow|deny [!]aclname ...
6008 This clause only supports fast acl types.
6009 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6011 snmp_access allow snmppublic localhost
6012 snmp_access deny all
6015 NAME: snmp_incoming_address
6017 LOC: Config.Addrs.snmp_incoming
6022 NAME: snmp_outgoing_address
6024 LOC: Config.Addrs.snmp_outgoing
6028 Just like 'udp_incoming_address', but for the SNMP port.
6030 snmp_incoming_address is used for the SNMP socket receiving
6031 messages from SNMP agents.
6032 snmp_outgoing_address is used for SNMP packets returned to SNMP
6035 The default snmp_incoming_address is to listen on all
6036 available network interfaces.
6038 If snmp_outgoing_address is not set it will use the same socket
6039 as snmp_incoming_address. Only change this if you want to have
6040 SNMP replies sent using another address than where this Squid
6041 listens for SNMP queries.
6043 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
6044 the same value since they both use port 3401.
6049 -----------------------------------------------------------------------------
6052 NAME: icp_port udp_port
6055 LOC: Config.Port.icp
6057 The port number where Squid sends and receives ICP queries to
6058 and from neighbor caches. The standard UDP port for ICP is 3130.
6059 Default is disabled (0).
6062 icp_port @DEFAULT_ICP_PORT@
6069 LOC: Config.Port.htcp
6071 The port number where Squid sends and receives HTCP queries to
6072 and from neighbor caches. To turn it on you want to set it to
6073 4827. By default it is set to "0" (disabled).
6079 NAME: log_icp_queries
6083 LOC: Config.onoff.log_udp
6085 If set, ICP queries are logged to access.log. You may wish
6086 do disable this if your ICP load is VERY high to speed things
6087 up or to simplify log analysis.
6090 NAME: udp_incoming_address
6092 LOC:Config.Addrs.udp_incoming
6095 udp_incoming_address is used for UDP packets received from other
6098 The default behavior is to not bind to any specific address.
6100 Only change this if you want to have all UDP queries received on
6101 a specific interface/address.
6103 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
6104 modules. Altering it will affect all of them in the same manner.
6106 see also; udp_outgoing_address
6108 NOTE, udp_incoming_address and udp_outgoing_address can not
6109 have the same value since they both use the same port.
6112 NAME: udp_outgoing_address
6114 LOC: Config.Addrs.udp_outgoing
6117 udp_outgoing_address is used for UDP packets sent out to other
6120 The default behavior is to not bind to any specific address.
6122 Instead it will use the same socket as udp_incoming_address.
6123 Only change this if you want to have UDP queries sent using another
6124 address than where this Squid listens for UDP queries from other
6127 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
6128 modules. Altering it will affect all of them in the same manner.
6130 see also; udp_incoming_address
6132 NOTE, udp_incoming_address and udp_outgoing_address can not
6133 have the same value since they both use the same port.
6140 LOC: Config.onoff.icp_hit_stale
6142 If you want to return ICP_HIT for stale cache objects, set this
6143 option to 'on'. If you have sibling relationships with caches
6144 in other administrative domains, this should be 'off'. If you only
6145 have sibling relationships with caches under your control,
6146 it is probably okay to set this to 'on'.
6147 If set to 'on', your siblings should use the option "allow-miss"
6148 on their cache_peer lines for connecting to you.
6151 NAME: minimum_direct_hops
6154 LOC: Config.minDirectHops
6156 If using the ICMP pinging stuff, do direct fetches for sites
6157 which are no more than this many hops away.
6160 NAME: minimum_direct_rtt
6163 LOC: Config.minDirectRtt
6165 If using the ICMP pinging stuff, do direct fetches for sites
6166 which are no more than this many rtt milliseconds away.
6172 LOC: Config.Netdb.low
6178 LOC: Config.Netdb.high
6180 The low and high water marks for the ICMP measurement
6181 database. These are counts, not percents. The defaults are
6182 900 and 1000. When the high water mark is reached, database
6183 entries will be deleted until the low mark is reached.
6186 NAME: netdb_ping_period
6188 LOC: Config.Netdb.period
6191 The minimum period for measuring a site. There will be at
6192 least this much delay between successive pings to the same
6193 network. The default is five minutes.
6200 LOC: Config.onoff.query_icmp
6202 If you want to ask your peers to include ICMP data in their ICP
6203 replies, enable this option.
6205 If your peer has configured Squid (during compilation) with
6206 '--enable-icmp' that peer will send ICMP pings to origin server
6207 sites of the URLs it receives. If you enable this option the
6208 ICP replies from that peer will include the ICMP data (if available).
6209 Then, when choosing a parent cache, Squid will choose the parent with
6210 the minimal RTT to the origin server. When this happens, the
6211 hierarchy field of the access.log will be
6212 "CLOSEST_PARENT_MISS". This option is off by default.
6215 NAME: test_reachability
6219 LOC: Config.onoff.test_reachability
6221 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
6222 instead of ICP_MISS if the target host is NOT in the ICMP
6223 database, or has a zero RTT.
6226 NAME: icp_query_timeout
6230 LOC: Config.Timeout.icp_query
6232 Normally Squid will automatically determine an optimal ICP
6233 query timeout value based on the round-trip-time of recent ICP
6234 queries. If you want to override the value determined by
6235 Squid, set this 'icp_query_timeout' to a non-zero value. This
6236 value is specified in MILLISECONDS, so, to use a 2-second
6237 timeout (the old default), you would write:
6239 icp_query_timeout 2000
6242 NAME: maximum_icp_query_timeout
6246 LOC: Config.Timeout.icp_query_max
6248 Normally the ICP query timeout is determined dynamically. But
6249 sometimes it can lead to very large values (say 5 seconds).
6250 Use this option to put an upper limit on the dynamic timeout
6251 value. Do NOT use this option to always use a fixed (instead
6252 of a dynamic) timeout value. To set a fixed timeout see the
6253 'icp_query_timeout' directive.
6256 NAME: minimum_icp_query_timeout
6260 LOC: Config.Timeout.icp_query_min
6262 Normally the ICP query timeout is determined dynamically. But
6263 sometimes it can lead to very small timeouts, even lower than
6264 the normal latency variance on your link due to traffic.
6265 Use this option to put an lower limit on the dynamic timeout
6266 value. Do NOT use this option to always use a fixed (instead
6267 of a dynamic) timeout value. To set a fixed timeout see the
6268 'icp_query_timeout' directive.
6271 NAME: background_ping_rate
6275 LOC: Config.backgroundPingRate
6277 Controls how often the ICP pings are sent to siblings that
6278 have background-ping set.
6282 MULTICAST ICP OPTIONS
6283 -----------------------------------------------------------------------------
6288 LOC: Config.mcast_group_list
6291 This tag specifies a list of multicast groups which your server
6292 should join to receive multicasted ICP queries.
6294 NOTE! Be very careful what you put here! Be sure you
6295 understand the difference between an ICP _query_ and an ICP
6296 _reply_. This option is to be set only if you want to RECEIVE
6297 multicast queries. Do NOT set this option to SEND multicast
6298 ICP (use cache_peer for that). ICP replies are always sent via
6299 unicast, so this option does not affect whether or not you will
6300 receive replies from multicast group members.
6302 You must be very careful to NOT use a multicast address which
6303 is already in use by another group of caches.
6305 If you are unsure about multicast, please read the Multicast
6306 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
6308 Usage: mcast_groups 239.128.16.128 224.0.1.20
6310 By default, Squid doesn't listen on any multicast groups.
6313 NAME: mcast_miss_addr
6314 IFDEF: MULTICAST_MISS_STREAM
6316 LOC: Config.mcast_miss.addr
6319 If you enable this option, every "cache miss" URL will
6320 be sent out on the specified multicast address.
6322 Do not enable this option unless you are are absolutely
6323 certain you understand what you are doing.
6326 NAME: mcast_miss_ttl
6327 IFDEF: MULTICAST_MISS_STREAM
6329 LOC: Config.mcast_miss.ttl
6332 This is the time-to-live value for packets multicasted
6333 when multicasting off cache miss URLs is enabled. By
6334 default this is set to 'site scope', i.e. 16.
6337 NAME: mcast_miss_port
6338 IFDEF: MULTICAST_MISS_STREAM
6340 LOC: Config.mcast_miss.port
6343 This is the port number to be used in conjunction with
6347 NAME: mcast_miss_encode_key
6348 IFDEF: MULTICAST_MISS_STREAM
6350 LOC: Config.mcast_miss.encode_key
6351 DEFAULT: XXXXXXXXXXXXXXXX
6353 The URLs that are sent in the multicast miss stream are
6354 encrypted. This is the encryption key.
6357 NAME: mcast_icp_query_timeout
6361 LOC: Config.Timeout.mcast_icp_query
6363 For multicast peers, Squid regularly sends out ICP "probes" to
6364 count how many other peers are listening on the given multicast
6365 address. This value specifies how long Squid should wait to
6366 count all the replies. The default is 2000 msec, or 2
6371 INTERNAL ICON OPTIONS
6372 -----------------------------------------------------------------------------
6375 NAME: icon_directory
6377 LOC: Config.icons.directory
6378 DEFAULT: @DEFAULT_ICON_DIR@
6380 Where the icons are stored. These are normally kept in
6384 NAME: global_internal_static
6386 LOC: Config.onoff.global_internal_static
6389 This directive controls is Squid should intercept all requests for
6390 /squid-internal-static/ no matter which host the URL is requesting
6391 (default on setting), or if nothing special should be done for
6392 such URLs (off setting). The purpose of this directive is to make
6393 icons etc work better in complex cache hierarchies where it may
6394 not always be possible for all corners in the cache mesh to reach
6395 the server generating a directory listing.
6398 NAME: short_icon_urls
6400 LOC: Config.icons.use_short_names
6403 If this is enabled Squid will use short URLs for icons.
6404 If disabled it will revert to the old behavior of including
6405 it's own name and port in the URL.
6407 If you run a complex cache hierarchy with a mix of Squid and
6408 other proxies you may need to disable this directive.
6413 -----------------------------------------------------------------------------
6416 NAME: error_directory
6418 LOC: Config.errorDirectory
6421 If you wish to create your own versions of the default
6422 error files to customize them to suit your company copy
6423 the error/template files to another directory and point
6426 WARNING: This option will disable multi-language support
6427 on error pages if used.
6429 The squid developers are interested in making squid available in
6430 a wide variety of languages. If you are making translations for a
6431 language that Squid does not currently provide please consider
6432 contributing your translation back to the project.
6433 http://wiki.squid-cache.org/Translations
6435 The squid developers working on translations are happy to supply drop-in
6436 translated error files in exchange for any new language contributions.
6439 NAME: error_default_language
6440 IFDEF: USE_ERR_LOCALES
6442 LOC: Config.errorDefaultLanguage
6445 Set the default language which squid will send error pages in
6446 if no existing translation matches the clients language
6449 If unset (default) generic English will be used.
6451 The squid developers are interested in making squid available in
6452 a wide variety of languages. If you are interested in making
6453 translations for any language see the squid wiki for details.
6454 http://wiki.squid-cache.org/Translations
6457 NAME: error_log_languages
6458 IFDEF: USE_ERR_LOCALES
6460 LOC: Config.errorLogMissingLanguages
6463 Log to cache.log what languages users are attempting to
6464 auto-negotiate for translations.
6466 Successful negotiations are not logged. Only failures
6467 have meaning to indicate that Squid may need an upgrade
6468 of its error page translations.
6471 NAME: err_page_stylesheet
6473 LOC: Config.errorStylesheet
6474 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
6476 CSS Stylesheet to pattern the display of Squid default error pages.
6478 For information on CSS see http://www.w3.org/Style/CSS/
6483 LOC: Config.errHtmlText
6486 HTML text to include in error messages. Make this a "mailto"
6487 URL to your admin address, or maybe just a link to your
6488 organizations Web page.
6490 To include this in your error messages, you must rewrite
6491 the error template files (found in the "errors" directory).
6492 Wherever you want the 'err_html_text' line to appear,
6493 insert a %L tag in the error template file.
6496 NAME: email_err_data
6499 LOC: Config.onoff.emailErrData
6502 If enabled, information about the occurred error will be
6503 included in the mailto links of the ERR pages (if %W is set)
6504 so that the email body contains the data.
6505 Syntax is <A HREF="mailto:%w%W">%w</A>
6510 LOC: Config.denyInfoList
6513 Usage: deny_info err_page_name acl
6514 or deny_info http://... acl
6515 or deny_info TCP_RESET acl
6517 This can be used to return a ERR_ page for requests which
6518 do not pass the 'http_access' rules. Squid remembers the last
6519 acl it evaluated in http_access, and if a 'deny_info' line exists
6520 for that ACL Squid returns a corresponding error page.
6522 The acl is typically the last acl on the http_access deny line which
6523 denied access. The exceptions to this rule are:
6524 - When Squid needs to request authentication credentials. It's then
6525 the first authentication related acl encountered
6526 - When none of the http_access lines matches. It's then the last
6527 acl processed on the last http_access line.
6528 - When the decision to deny access was made by an adaptation service,
6529 the acl name is the corresponding eCAP or ICAP service_name.
6531 NP: If providing your own custom error pages with error_directory
6532 you may also specify them by your custom file name:
6533 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
6535 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
6536 may be specified by prefixing the file name with the code and a colon.
6537 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
6539 Alternatively you can tell Squid to reset the TCP connection
6540 by specifying TCP_RESET.
6542 Or you can specify an error URL or URL pattern. The browsers will
6543 get redirected to the specified URL after formatting tags have
6544 been replaced. Redirect will be done with 302 or 307 according to
6545 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
6546 the URL. e.g. 303:http://example.com/
6549 %a - username (if available. Password NOT included)
6552 %E - Error description
6554 %H - Request domain name
6555 %i - Client IP Address
6557 %o - Message result from external ACL helper
6558 %p - Request Port number
6559 %P - Request Protocol name
6560 %R - Request URL path
6561 %T - Timestamp in RFC 1123 format
6562 %U - Full canonical URL from client
6563 (HTTPS URLs terminate with *)
6564 %u - Full canonical URL from client
6565 %w - Admin email from squid.conf
6567 %% - Literal percent (%) code
6572 OPTIONS INFLUENCING REQUEST FORWARDING
6573 -----------------------------------------------------------------------------
6576 NAME: nonhierarchical_direct
6578 LOC: Config.onoff.nonhierarchical_direct
6581 By default, Squid will send any non-hierarchical requests
6582 (matching hierarchy_stoplist or not cacheable request type) direct
6585 If you set this to off, Squid will prefer to send these
6586 requests to parents.
6588 Note that in most configurations, by turning this off you will only
6589 add latency to these request without any improvement in global hit
6592 If you are inside an firewall see never_direct instead of
6598 LOC: Config.onoff.prefer_direct
6601 Normally Squid tries to use parents for most requests. If you for some
6602 reason like it to first try going direct and only use a parent if
6603 going direct fails set this to on.
6605 By combining nonhierarchical_direct off and prefer_direct on you
6606 can set up Squid to use a parent as a backup path if going direct
6609 Note: If you want Squid to use parents for all requests see
6610 the never_direct directive. prefer_direct only modifies how Squid
6611 acts on cacheable requests.
6616 LOC: Config.accessList.AlwaysDirect
6619 Usage: always_direct allow|deny [!]aclname ...
6621 Here you can use ACL elements to specify requests which should
6622 ALWAYS be forwarded by Squid to the origin servers without using
6623 any peers. For example, to always directly forward requests for
6624 local servers ignoring any parents or siblings you may have use
6627 acl local-servers dstdomain my.domain.net
6628 always_direct allow local-servers
6630 To always forward FTP requests directly, use
6633 always_direct allow FTP
6635 NOTE: There is a similar, but opposite option named
6636 'never_direct'. You need to be aware that "always_direct deny
6637 foo" is NOT the same thing as "never_direct allow foo". You
6638 may need to use a deny rule to exclude a more-specific case of
6639 some other rule. Example:
6641 acl local-external dstdomain external.foo.net
6642 acl local-servers dstdomain .foo.net
6643 always_direct deny local-external
6644 always_direct allow local-servers
6646 NOTE: If your goal is to make the client forward the request
6647 directly to the origin server bypassing Squid then this needs
6648 to be done in the client configuration. Squid configuration
6649 can only tell Squid how Squid should fetch the object.
6651 NOTE: This directive is not related to caching. The replies
6652 is cached as usual even if you use always_direct. To not cache
6653 the replies see the 'cache' directive.
6655 This clause supports both fast and slow acl types.
6656 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6661 LOC: Config.accessList.NeverDirect
6664 Usage: never_direct allow|deny [!]aclname ...
6666 never_direct is the opposite of always_direct. Please read
6667 the description for always_direct if you have not already.
6669 With 'never_direct' you can use ACL elements to specify
6670 requests which should NEVER be forwarded directly to origin
6671 servers. For example, to force the use of a proxy for all
6672 requests, except those in your local domain use something like:
6674 acl local-servers dstdomain .foo.net
6675 never_direct deny local-servers
6676 never_direct allow all
6678 or if Squid is inside a firewall and there are local intranet
6679 servers inside the firewall use something like:
6681 acl local-intranet dstdomain .foo.net
6682 acl local-external dstdomain external.foo.net
6683 always_direct deny local-external
6684 always_direct allow local-intranet
6685 never_direct allow all
6687 This clause supports both fast and slow acl types.
6688 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6692 ADVANCED NETWORKING OPTIONS
6693 -----------------------------------------------------------------------------
6696 NAME: incoming_udp_average incoming_icp_average
6699 LOC: Config.comm_incoming.udp.average
6701 Heavy voodoo here. I can't even believe you are reading this.
6702 Are you crazy? Don't even think about adjusting these unless
6703 you understand the algorithms in comm_select.c first!
6706 NAME: incoming_tcp_average incoming_http_average
6709 LOC: Config.comm_incoming.tcp.average
6711 Heavy voodoo here. I can't even believe you are reading this.
6712 Are you crazy? Don't even think about adjusting these unless
6713 you understand the algorithms in comm_select.c first!
6716 NAME: incoming_dns_average
6719 LOC: Config.comm_incoming.dns.average
6721 Heavy voodoo here. I can't even believe you are reading this.
6722 Are you crazy? Don't even think about adjusting these unless
6723 you understand the algorithms in comm_select.c first!
6726 NAME: min_udp_poll_cnt min_icp_poll_cnt
6729 LOC: Config.comm_incoming.udp.min_poll
6731 Heavy voodoo here. I can't even believe you are reading this.
6732 Are you crazy? Don't even think about adjusting these unless
6733 you understand the algorithms in comm_select.c first!
6736 NAME: min_dns_poll_cnt
6739 LOC: Config.comm_incoming.dns.min_poll
6741 Heavy voodoo here. I can't even believe you are reading this.
6742 Are you crazy? Don't even think about adjusting these unless
6743 you understand the algorithms in comm_select.c first!
6746 NAME: min_tcp_poll_cnt min_http_poll_cnt
6749 LOC: Config.comm_incoming.tcp.min_poll
6751 Heavy voodoo here. I can't even believe you are reading this.
6752 Are you crazy? Don't even think about adjusting these unless
6753 you understand the algorithms in comm_select.c first!
6759 LOC: Config.accept_filter
6763 The name of an accept(2) filter to install on Squid's
6764 listen socket(s). This feature is perhaps specific to
6765 FreeBSD and requires support in the kernel.
6767 The 'httpready' filter delays delivering new connections
6768 to Squid until a full HTTP request has been received.
6769 See the accf_http(9) man page for details.
6771 The 'dataready' filter delays delivering new connections
6772 to Squid until there is some data to process.
6773 See the accf_dataready(9) man page for details.
6777 The 'data' filter delays delivering of new connections
6778 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
6779 You may optionally specify a number of seconds to wait by
6780 'data=N' where N is the number of seconds. Defaults to 30
6781 if not specified. See the tcp(7) man page for details.
6784 accept_filter httpready
6789 NAME: client_ip_max_connections
6791 LOC: Config.client_ip_max_connections
6794 Set an absolute limit on the number of connections a single
6795 client IP can use. Any more than this and Squid will begin to drop
6796 new connections from the client until it closes some links.
6798 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
6799 connections from the client. For finer control use the ACL access controls.
6801 Requires client_db to be enabled (the default).
6803 WARNING: This may noticably slow down traffic received via external proxies
6804 or NAT devices and cause them to rebound error messages back to their clients.
6807 NAME: tcp_recv_bufsize
6811 LOC: Config.tcpRcvBufsz
6813 Size of receive buffer to set for TCP sockets. Probably just
6814 as easy to change your kernel's default. Set to zero to use
6815 the default buffer size.
6820 -----------------------------------------------------------------------------
6827 LOC: Adaptation::Icap::TheConfig.onoff
6830 If you want to enable the ICAP module support, set this to on.
6833 NAME: icap_connect_timeout
6836 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
6839 This parameter specifies how long to wait for the TCP connect to
6840 the requested ICAP server to complete before giving up and either
6841 terminating the HTTP transaction or bypassing the failure.
6843 The default for optional services is peer_connect_timeout.
6844 The default for essential services is connect_timeout.
6845 If this option is explicitly set, its value applies to all services.
6848 NAME: icap_io_timeout
6852 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
6855 This parameter specifies how long to wait for an I/O activity on
6856 an established, active ICAP connection before giving up and
6857 either terminating the HTTP transaction or bypassing the
6860 The default is read_timeout.
6863 NAME: icap_service_failure_limit
6864 COMMENT: limit [in memory-depth time-units]
6865 TYPE: icap_service_failure_limit
6867 LOC: Adaptation::Icap::TheConfig
6870 The limit specifies the number of failures that Squid tolerates
6871 when establishing a new TCP connection with an ICAP service. If
6872 the number of failures exceeds the limit, the ICAP service is
6873 not used for new ICAP requests until it is time to refresh its
6876 A negative value disables the limit. Without the limit, an ICAP
6877 service will not be considered down due to connectivity failures
6878 between ICAP OPTIONS requests.
6880 Squid forgets ICAP service failures older than the specified
6881 value of memory-depth. The memory fading algorithm
6882 is approximate because Squid does not remember individual
6883 errors but groups them instead, splitting the option
6884 value into ten time slots of equal length.
6886 When memory-depth is 0 and by default this option has no
6887 effect on service failure expiration.
6889 Squid always forgets failures when updating service settings
6890 using an ICAP OPTIONS transaction, regardless of this option
6894 # suspend service usage after 10 failures in 5 seconds:
6895 icap_service_failure_limit 10 in 5 seconds
6898 NAME: icap_service_revival_delay
6901 LOC: Adaptation::Icap::TheConfig.service_revival_delay
6904 The delay specifies the number of seconds to wait after an ICAP
6905 OPTIONS request failure before requesting the options again. The
6906 failed ICAP service is considered "down" until fresh OPTIONS are
6909 The actual delay cannot be smaller than the hardcoded minimum
6910 delay of 30 seconds.
6913 NAME: icap_preview_enable
6917 LOC: Adaptation::Icap::TheConfig.preview_enable
6920 The ICAP Preview feature allows the ICAP server to handle the
6921 HTTP message by looking only at the beginning of the message body
6922 or even without receiving the body at all. In some environments,
6923 previews greatly speedup ICAP processing.
6925 During an ICAP OPTIONS transaction, the server may tell Squid what
6926 HTTP messages should be previewed and how big the preview should be.
6927 Squid will not use Preview if the server did not request one.
6929 To disable ICAP Preview for all ICAP services, regardless of
6930 individual ICAP server OPTIONS responses, set this option to "off".
6932 icap_preview_enable off
6935 NAME: icap_preview_size
6938 LOC: Adaptation::Icap::TheConfig.preview_size
6941 The default size of preview data to be sent to the ICAP server.
6942 -1 means no preview. This value might be overwritten on a per server
6943 basis by OPTIONS requests.
6946 NAME: icap_206_enable
6950 LOC: Adaptation::Icap::TheConfig.allow206_enable
6953 206 (Partial Content) responses is an ICAP extension that allows the
6954 ICAP agents to optionally combine adapted and original HTTP message
6955 content. The decision to combine is postponed until the end of the
6956 ICAP response. Squid supports Partial Content extension by default.
6958 Activation of the Partial Content extension is negotiated with each
6959 ICAP service during OPTIONS exchange. Most ICAP servers should handle
6960 negotation correctly even if they do not support the extension, but
6961 some might fail. To disable Partial Content support for all ICAP
6962 services and to avoid any negotiation, set this option to "off".
6968 NAME: icap_default_options_ttl
6971 LOC: Adaptation::Icap::TheConfig.default_options_ttl
6974 The default TTL value for ICAP OPTIONS responses that don't have
6975 an Options-TTL header.
6978 NAME: icap_persistent_connections
6982 LOC: Adaptation::Icap::TheConfig.reuse_connections
6985 Whether or not Squid should use persistent connections to
6989 NAME: adaptation_send_client_ip icap_send_client_ip
6991 IFDEF: USE_ADAPTATION
6993 LOC: Adaptation::Config::send_client_ip
6996 If enabled, Squid shares HTTP client IP information with adaptation
6997 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
6998 For eCAP, Squid sets the libecap::metaClientIp transaction option.
7000 See also: adaptation_uses_indirect_client
7003 NAME: adaptation_send_username icap_send_client_username
7005 IFDEF: USE_ADAPTATION
7007 LOC: Adaptation::Config::send_username
7010 This sends authenticated HTTP client username (if available) to
7011 the adaptation service.
7013 For ICAP, the username value is encoded based on the
7014 icap_client_username_encode option and is sent using the header
7015 specified by the icap_client_username_header option.
7018 NAME: icap_client_username_header
7021 LOC: Adaptation::Icap::TheConfig.client_username_header
7022 DEFAULT: X-Client-Username
7024 ICAP request header name to use for adaptation_send_username.
7027 NAME: icap_client_username_encode
7031 LOC: Adaptation::Icap::TheConfig.client_username_encode
7034 Whether to base64 encode the authenticated client username.
7038 TYPE: icap_service_type
7040 LOC: Adaptation::Icap::TheConfig
7043 Defines a single ICAP service using the following format:
7045 icap_service id vectoring_point uri [option ...]
7048 an opaque identifier or name which is used to direct traffic to
7049 this specific service. Must be unique among all adaptation
7050 services in squid.conf.
7052 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7053 This specifies at which point of transaction processing the
7054 ICAP service should be activated. *_postcache vectoring points
7055 are not yet supported.
7057 uri: icap://servername:port/servicepath
7058 ICAP server and service location.
7060 ICAP does not allow a single service to handle both REQMOD and RESPMOD
7061 transactions. Squid does not enforce that requirement. You can specify
7062 services with the same service_url and different vectoring_points. You
7063 can even specify multiple identical services as long as their
7064 service_names differ.
7067 Service options are separated by white space. ICAP services support
7068 the following name=value options:
7071 If set to 'on' or '1', the ICAP service is treated as
7072 optional. If the service cannot be reached or malfunctions,
7073 Squid will try to ignore any errors and process the message as
7074 if the service was not enabled. No all ICAP errors can be
7075 bypassed. If set to 0, the ICAP service is treated as
7076 essential and all ICAP errors will result in an error page
7077 returned to the HTTP client.
7079 Bypass is off by default: services are treated as essential.
7082 If set to 'on' or '1', the ICAP service is allowed to
7083 dynamically change the current message adaptation plan by
7084 returning a chain of services to be used next. The services
7085 are specified using the X-Next-Services ICAP response header
7086 value, formatted as a comma-separated list of service names.
7087 Each named service should be configured in squid.conf. Other
7088 services are ignored. An empty X-Next-Services value results
7089 in an empty plan which ends the current adaptation.
7091 Dynamic adaptation plan may cross or cover multiple supported
7092 vectoring points in their natural processing order.
7094 Routing is not allowed by default: the ICAP X-Next-Services
7095 response header is ignored.
7098 Only has effect on split-stack systems. The default on those systems
7099 is to use IPv4-only connections. When set to 'on' this option will
7100 make Squid use IPv6-only connections to contact this ICAP service.
7102 on-overload=block|bypass|wait|force
7103 If the service Max-Connections limit has been reached, do
7104 one of the following for each new ICAP transaction:
7105 * block: send an HTTP error response to the client
7106 * bypass: ignore the "over-connected" ICAP service
7107 * wait: wait (in a FIFO queue) for an ICAP connection slot
7108 * force: proceed, ignoring the Max-Connections limit
7110 In SMP mode with N workers, each worker assumes the service
7111 connection limit is Max-Connections/N, even though not all
7112 workers may use a given service.
7114 The default value is "bypass" if service is bypassable,
7115 otherwise it is set to "wait".
7119 Use the given number as the Max-Connections limit, regardless
7120 of the Max-Connections value given by the service, if any.
7122 Older icap_service format without optional named parameters is
7123 deprecated but supported for backward compatibility.
7126 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
7127 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
7131 TYPE: icap_class_type
7136 This deprecated option was documented to define an ICAP service
7137 chain, even though it actually defined a set of similar, redundant
7138 services, and the chains were not supported.
7140 To define a set of redundant services, please use the
7141 adaptation_service_set directive. For service chains, use
7142 adaptation_service_chain.
7146 TYPE: icap_access_type
7151 This option is deprecated. Please use adaptation_access, which
7152 has the same ICAP functionality, but comes with better
7153 documentation, and eCAP support.
7158 -----------------------------------------------------------------------------
7165 LOC: Adaptation::Ecap::TheConfig.onoff
7168 Controls whether eCAP support is enabled.
7172 TYPE: ecap_service_type
7174 LOC: Adaptation::Ecap::TheConfig
7177 Defines a single eCAP service
7179 ecap_service id vectoring_point uri [option ...]
7182 an opaque identifier or name which is used to direct traffic to
7183 this specific service. Must be unique among all adaptation
7184 services in squid.conf.
7186 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7187 This specifies at which point of transaction processing the
7188 eCAP service should be activated. *_postcache vectoring points
7189 are not yet supported.
7191 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
7192 Squid uses the eCAP service URI to match this configuration
7193 line with one of the dynamically loaded services. Each loaded
7194 eCAP service must have a unique URI. Obtain the right URI from
7195 the service provider.
7198 Service options are separated by white space. eCAP services support
7199 the following name=value options:
7202 If set to 'on' or '1', the eCAP service is treated as optional.
7203 If the service cannot be reached or malfunctions, Squid will try
7204 to ignore any errors and process the message as if the service
7205 was not enabled. No all eCAP errors can be bypassed.
7206 If set to 'off' or '0', the eCAP service is treated as essential
7207 and all eCAP errors will result in an error page returned to the
7210 Bypass is off by default: services are treated as essential.
7213 If set to 'on' or '1', the eCAP service is allowed to
7214 dynamically change the current message adaptation plan by
7215 returning a chain of services to be used next.
7217 Dynamic adaptation plan may cross or cover multiple supported
7218 vectoring points in their natural processing order.
7220 Routing is not allowed by default.
7222 Older ecap_service format without optional named parameters is
7223 deprecated but supported for backward compatibility.
7227 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
7228 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
7231 NAME: loadable_modules
7233 IFDEF: USE_LOADABLE_MODULES
7234 LOC: Config.loadable_module_names
7237 Instructs Squid to load the specified dynamic module(s) or activate
7238 preloaded module(s).
7240 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
7244 MESSAGE ADAPTATION OPTIONS
7245 -----------------------------------------------------------------------------
7248 NAME: adaptation_service_set
7249 TYPE: adaptation_service_set_type
7250 IFDEF: USE_ADAPTATION
7255 Configures an ordered set of similar, redundant services. This is
7256 useful when hot standby or backup adaptation servers are available.
7258 adaptation_service_set set_name service_name1 service_name2 ...
7260 The named services are used in the set declaration order. The first
7261 applicable adaptation service from the set is used first. The next
7262 applicable service is tried if and only if the transaction with the
7263 previous service fails and the message waiting to be adapted is still
7266 When adaptation starts, broken services are ignored as if they were
7267 not a part of the set. A broken service is a down optional service.
7269 The services in a set must be attached to the same vectoring point
7270 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7272 If all services in a set are optional then adaptation failures are
7273 bypassable. If all services in the set are essential, then a
7274 transaction failure with one service may still be retried using
7275 another service from the set, but when all services fail, the master
7276 transaction fails as well.
7278 A set may contain a mix of optional and essential services, but that
7279 is likely to lead to surprising results because broken services become
7280 ignored (see above), making previously bypassable failures fatal.
7281 Technically, it is the bypassability of the last failed service that
7284 See also: adaptation_access adaptation_service_chain
7287 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
7288 adaptation service_set svcLogger loggerLocal loggerRemote
7291 NAME: adaptation_service_chain
7292 TYPE: adaptation_service_chain_type
7293 IFDEF: USE_ADAPTATION
7298 Configures a list of complementary services that will be applied
7299 one-by-one, forming an adaptation chain or pipeline. This is useful
7300 when Squid must perform different adaptations on the same message.
7302 adaptation_service_chain chain_name service_name1 svc_name2 ...
7304 The named services are used in the chain declaration order. The first
7305 applicable adaptation service from the chain is used first. The next
7306 applicable service is applied to the successful adaptation results of
7307 the previous service in the chain.
7309 When adaptation starts, broken services are ignored as if they were
7310 not a part of the chain. A broken service is a down optional service.
7312 Request satisfaction terminates the adaptation chain because Squid
7313 does not currently allow declaration of RESPMOD services at the
7314 "reqmod_precache" vectoring point (see icap_service or ecap_service).
7316 The services in a chain must be attached to the same vectoring point
7317 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7319 A chain may contain a mix of optional and essential services. If an
7320 essential adaptation fails (or the failure cannot be bypassed for
7321 other reasons), the master transaction fails. Otherwise, the failure
7322 is bypassed as if the failed adaptation service was not in the chain.
7324 See also: adaptation_access adaptation_service_set
7327 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
7330 NAME: adaptation_access
7331 TYPE: adaptation_access_type
7332 IFDEF: USE_ADAPTATION
7336 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
7338 adaptation_access service_name allow|deny [!]aclname...
7339 adaptation_access set_name allow|deny [!]aclname...
7341 At each supported vectoring point, the adaptation_access
7342 statements are processed in the order they appear in this
7343 configuration file. Statements pointing to the following services
7344 are ignored (i.e., skipped without checking their ACL):
7346 - services serving different vectoring points
7347 - "broken-but-bypassable" services
7348 - "up" services configured to ignore such transactions
7349 (e.g., based on the ICAP Transfer-Ignore header).
7351 When a set_name is used, all services in the set are checked
7352 using the same rules, to find the first applicable one. See
7353 adaptation_service_set for details.
7355 If an access list is checked and there is a match, the
7356 processing stops: For an "allow" rule, the corresponding
7357 adaptation service is used for the transaction. For a "deny"
7358 rule, no adaptation service is activated.
7360 It is currently not possible to apply more than one adaptation
7361 service at the same vectoring point to the same HTTP transaction.
7363 See also: icap_service and ecap_service
7366 adaptation_access service_1 allow all
7369 NAME: adaptation_service_iteration_limit
7371 IFDEF: USE_ADAPTATION
7372 LOC: Adaptation::Config::service_iteration_limit
7375 Limits the number of iterations allowed when applying adaptation
7376 services to a message. If your longest adaptation set or chain
7377 may have more than 16 services, increase the limit beyond its
7378 default value of 16. If detecting infinite iteration loops sooner
7379 is critical, make the iteration limit match the actual number
7380 of services in your longest adaptation set or chain.
7382 Infinite adaptation loops are most likely with routing services.
7384 See also: icap_service routing=1
7387 NAME: adaptation_masterx_shared_names
7389 IFDEF: USE_ADAPTATION
7390 LOC: Adaptation::Config::masterx_shared_name
7393 For each master transaction (i.e., the HTTP request and response
7394 sequence, including all related ICAP and eCAP exchanges), Squid
7395 maintains a table of metadata. The table entries are (name, value)
7396 pairs shared among eCAP and ICAP exchanges. The table is destroyed
7397 with the master transaction.
7399 This option specifies the table entry names that Squid must accept
7400 from and forward to the adaptation transactions.
7402 An ICAP REQMOD or RESPMOD transaction may set an entry in the
7403 shared table by returning an ICAP header field with a name
7404 specified in adaptation_masterx_shared_names.
7406 An eCAP REQMOD or RESPMOD transaction may set an entry in the
7407 shared table by implementing the libecap::visitEachOption() API
7408 to provide an option with a name specified in
7409 adaptation_masterx_shared_names.
7411 Squid will store and forward the set entry to subsequent adaptation
7412 transactions within the same master transaction scope.
7414 Only one shared entry name is supported at this time.
7417 # share authentication information among ICAP services
7418 adaptation_masterx_shared_names X-Subscriber-ID
7421 NAME: adaptation_meta
7423 IFDEF: USE_ADAPTATION
7424 LOC: Adaptation::Config::metaHeaders
7427 This option allows Squid administrator to add custom ICAP request
7428 headers or eCAP options to Squid ICAP requests or eCAP transactions.
7429 Use it to pass custom authentication tokens and other
7430 transaction-state related meta information to an ICAP/eCAP service.
7432 The addition of a meta header is ACL-driven:
7433 adaptation_meta name value [!]aclname ...
7435 Processing for a given header name stops after the first ACL list match.
7436 Thus, it is impossible to add two headers with the same name. If no ACL
7437 lists match for a given header name, no such header is added. For
7440 # do not debug transactions except for those that need debugging
7441 adaptation_meta X-Debug 1 needs_debugging
7443 # log all transactions except for those that must remain secret
7444 adaptation_meta X-Log 1 !keep_secret
7446 # mark transactions from users in the "G 1" group
7447 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
7449 The "value" parameter may be a regular squid.conf token or a "double
7450 quoted string". Within the quoted string, use backslash (\) to escape
7451 any character, which is currently only useful for escaping backslashes
7452 and double quotes. For example,
7453 "this string has one backslash (\\) and two \"quotes\""
7455 Used adaptation_meta header values may be logged via %note
7456 logformat code. If multiple adaptation_meta headers with the same name
7457 are used during master transaction lifetime, the header values are
7458 logged in the order they were used and duplicate values are ignored
7459 (only the first repeated value will be logged).
7465 LOC: Adaptation::Icap::TheConfig.repeat
7466 DEFAULT_IF_NONE: deny all
7468 This ACL determines which retriable ICAP transactions are
7469 retried. Transactions that received a complete ICAP response
7470 and did not have to consume or produce HTTP bodies to receive
7471 that response are usually retriable.
7473 icap_retry allow|deny [!]aclname ...
7475 Squid automatically retries some ICAP I/O timeouts and errors
7476 due to persistent connection race conditions.
7478 See also: icap_retry_limit
7481 NAME: icap_retry_limit
7484 LOC: Adaptation::Icap::TheConfig.repeat_limit
7487 Limits the number of retries allowed. When set to zero (default),
7488 no retries are allowed.
7490 Communication errors due to persistent connection race
7491 conditions are unavoidable, automatically retried, and do not
7492 count against this limit.
7494 See also: icap_retry
7500 -----------------------------------------------------------------------------
7503 NAME: check_hostnames
7506 LOC: Config.onoff.check_hostnames
7508 For security and stability reasons Squid can check
7509 hostnames for Internet standard RFC compliance. If you want
7510 Squid to perform these checks turn this directive on.
7513 NAME: allow_underscore
7516 LOC: Config.onoff.allow_underscore
7518 Underscore characters is not strictly allowed in Internet hostnames
7519 but nevertheless used by many sites. Set this to off if you want
7520 Squid to be strict about the standard.
7521 This check is performed only when check_hostnames is set to on.
7524 NAME: cache_dns_program
7526 IFDEF: USE_DNSHELPER
7527 DEFAULT: @DEFAULT_DNSSERVER@
7528 LOC: Config.Program.dnsserver
7530 Specify the location of the executable for dnslookup process.
7534 TYPE: HelperChildConfig
7535 IFDEF: USE_DNSHELPER
7536 DEFAULT: 32 startup=1 idle=1
7537 LOC: Config.dnsChildren
7539 The maximum number of processes spawn to service DNS name lookups.
7540 If you limit it too few Squid will have to wait for them to process
7541 a backlog of requests, slowing it down. If you allow too many they
7542 will use RAM and other system resources noticably.
7543 The maximum this may be safely set to is 32.
7545 The startup= and idle= options allow some measure of skew in your
7550 Sets a minimum of how many processes are to be spawned when Squid
7551 starts or reconfigures. When set to zero the first request will
7552 cause spawning of the first child process to handle it.
7554 Starting too few will cause an initial slowdown in traffic as Squid
7555 attempts to simultaneously spawn enough processes to cope.
7559 Sets a minimum of how many processes Squid is to try and keep available
7560 at all times. When traffic begins to rise above what the existing
7561 processes can handle this many more will be spawned up to the maximum
7562 configured. A minimum setting of 1 is required.
7565 NAME: dns_retransmit_interval
7568 LOC: Config.Timeout.idns_retransmit
7569 IFDEF: !USE_DNSHELPER
7571 Initial retransmit interval for DNS queries. The interval is
7572 doubled each time all configured DNS servers have been tried.
7578 LOC: Config.Timeout.idns_query
7579 IFDEF: !USE_DNSHELPER
7581 DNS Query timeout. If no response is received to a DNS query
7582 within this time all DNS servers for the queried domain
7583 are assumed to be unavailable.
7586 NAME: dns_packet_max
7589 LOC: Config.dns.packet_max
7590 IFDEF: !USE_DNSHELPER
7592 Maximum number of bytes packet size to advertise via EDNS.
7593 Set to "none" to disable EDNS large packet support.
7595 For legacy reasons DNS UDP replies will default to 512 bytes which
7596 is too small for many responses. EDNS provides a means for Squid to
7597 negotiate receiving larger responses back immediately without having
7598 to failover with repeat requests. Responses larger than this limit
7599 will retain the old behaviour of failover to TCP DNS.
7601 Squid has no real fixed limit internally, but allowing packet sizes
7602 over 1500 bytes requires network jumbogram support and is usually not
7605 WARNING: The RFC also indicates that some older resolvers will reply
7606 with failure of the whole request if the extension is added. Some
7607 resolvers have already been identified which will reply with mangled
7608 EDNS response on occasion. Usually in response to many-KB jumbogram
7609 sizes being advertised by Squid.
7610 Squid will currently treat these both as an unable-to-resolve domain
7611 even if it would be resolvable without EDNS.
7618 LOC: Config.onoff.res_defnames
7620 Normally the RES_DEFNAMES resolver option is disabled
7621 (see res_init(3)). This prevents caches in a hierarchy
7622 from interpreting single-component hostnames locally. To allow
7623 Squid to handle single-component names, enable this option.
7626 NAME: dns_nameservers
7629 LOC: Config.dns_nameservers
7631 Use this if you want to specify a list of DNS name servers
7632 (IP addresses) to use instead of those given in your
7633 /etc/resolv.conf file.
7634 On Windows platforms, if no value is specified here or in
7635 the /etc/resolv.conf file, the list of DNS name servers are
7636 taken from the Windows registry, both static and dynamic DHCP
7637 configurations are supported.
7639 Example: dns_nameservers 10.0.0.1 192.172.0.4
7644 DEFAULT: @DEFAULT_HOSTS@
7645 LOC: Config.etcHostsPath
7647 Location of the host-local IP name-address associations
7648 database. Most Operating Systems have such a file on different
7650 - Un*X & Linux: /etc/hosts
7651 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
7652 (%SystemRoot% value install default is c:\winnt)
7653 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
7654 (%SystemRoot% value install default is c:\windows)
7655 - Windows 9x/Me: %windir%\hosts
7656 (%windir% value is usually c:\windows)
7657 - Cygwin: /etc/hosts
7659 The file contains newline-separated definitions, in the
7660 form ip_address_in_dotted_form name [name ...] names are
7661 whitespace-separated. Lines beginning with an hash (#)
7662 character are comments.
7664 The file is checked at startup and upon configuration.
7665 If set to 'none', it won't be checked.
7666 If append_domain is used, that domain will be added to
7667 domain-local (i.e. not containing any dot character) host
7673 LOC: Config.appendDomain
7676 Appends local domain name to hostnames without any dots in
7677 them. append_domain must begin with a period.
7679 Be warned there are now Internet names with no dots in
7680 them using only top-domain names, so setting this may
7681 cause some Internet sites to become unavailable.
7684 append_domain .yourdomain.com
7687 NAME: ignore_unknown_nameservers
7689 LOC: Config.onoff.ignore_unknown_nameservers
7691 IFDEF: !USE_DNSHELPER
7693 By default Squid checks that DNS responses are received
7694 from the same IP addresses they are sent to. If they
7695 don't match, Squid ignores the response and writes a warning
7696 message to cache.log. You can allow responses from unknown
7697 nameservers by setting this option to 'off'.
7703 LOC: Config.dns.v4_first
7704 IFDEF: !USE_DNSHELPER
7706 With the IPv6 Internet being as fast or faster than IPv4 Internet
7707 for most networks Squid prefers to contact websites over IPv6.
7709 This option reverses the order of preference to make Squid contact
7710 dual-stack websites over IPv4 first. Squid will still perform both
7711 IPv6 and IPv4 DNS lookups before connecting.
7714 This option will restrict the situations under which IPv6
7715 connectivity is used (and tested). Hiding network problems
7716 which would otherwise be detected and warned about.
7720 COMMENT: (number of entries)
7723 LOC: Config.ipcache.size
7730 LOC: Config.ipcache.low
7737 LOC: Config.ipcache.high
7739 The size, low-, and high-water marks for the IP cache.
7742 NAME: fqdncache_size
7743 COMMENT: (number of entries)
7746 LOC: Config.fqdncache.size
7748 Maximum number of FQDN cache entries.
7753 -----------------------------------------------------------------------------
7760 LOC: Config.onoff.mem_pools
7762 If set, Squid will keep pools of allocated (but unused) memory
7763 available for future use. If memory is a premium on your
7764 system and you believe your malloc library outperforms Squid
7765 routines, disable this.
7768 NAME: memory_pools_limit
7772 LOC: Config.MemPools.limit
7774 Used only with memory_pools on:
7775 memory_pools_limit 50 MB
7777 If set to a non-zero value, Squid will keep at most the specified
7778 limit of allocated (but unused) memory in memory pools. All free()
7779 requests that exceed this limit will be handled by your malloc
7780 library. Squid does not pre-allocate any memory, just safe-keeps
7781 objects that otherwise would be free()d. Thus, it is safe to set
7782 memory_pools_limit to a reasonably high value even if your
7783 configuration will use less memory.
7785 If set to none, Squid will keep all memory it can. That is, there
7786 will be no limit on the total amount of memory used for safe-keeping.
7788 To disable memory allocation optimization, do not set
7789 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
7791 An overhead for maintaining memory pools is not taken into account
7792 when the limit is checked. This overhead is close to four bytes per
7793 object kept. However, pools may actually _save_ memory because of
7794 reduced memory thrashing in your malloc library.
7798 COMMENT: on|off|transparent|truncate|delete
7801 LOC: opt_forwarded_for
7803 If set to "on", Squid will append your client's IP address
7804 in the HTTP requests it forwards. By default it looks like:
7806 X-Forwarded-For: 192.1.2.3
7808 If set to "off", it will appear as
7810 X-Forwarded-For: unknown
7812 If set to "transparent", Squid will not alter the
7813 X-Forwarded-For header in any way.
7815 If set to "delete", Squid will delete the entire
7816 X-Forwarded-For header.
7818 If set to "truncate", Squid will remove all existing
7819 X-Forwarded-For entries, and place the client IP as the sole entry.
7822 NAME: cachemgr_passwd
7823 TYPE: cachemgrpasswd
7825 LOC: Config.passwd_list
7827 Specify passwords for cachemgr operations.
7829 Usage: cachemgr_passwd password action action ...
7831 Some valid actions are (see cache manager menu for a full list):
7871 * Indicates actions which will not be performed without a
7872 valid password, others can be performed if not listed here.
7874 To disable an action, set the password to "disable".
7875 To allow performing an action without a password, set the
7878 Use the keyword "all" to set the same password for all actions.
7881 cachemgr_passwd secret shutdown
7882 cachemgr_passwd lesssssssecret info stats/objects
7883 cachemgr_passwd disable all
7890 LOC: Config.onoff.client_db
7892 If you want to disable collecting per-client statistics,
7893 turn off client_db here.
7896 NAME: refresh_all_ims
7900 LOC: Config.onoff.refresh_all_ims
7902 When you enable this option, squid will always check
7903 the origin server for an update when a client sends an
7904 If-Modified-Since request. Many browsers use IMS
7905 requests when the user requests a reload, and this
7906 ensures those clients receive the latest version.
7908 By default (off), squid may return a Not Modified response
7909 based on the age of the cached version.
7912 NAME: reload_into_ims
7913 IFDEF: USE_HTTP_VIOLATIONS
7917 LOC: Config.onoff.reload_into_ims
7919 When you enable this option, client no-cache or ``reload''
7920 requests will be changed to If-Modified-Since requests.
7921 Doing this VIOLATES the HTTP standard. Enabling this
7922 feature could make you liable for problems which it
7925 see also refresh_pattern for a more selective approach.
7928 NAME: connect_retries
7930 LOC: Config.connect_retries
7933 This sets the maximum number of connection attempts made for each
7934 TCP connection. The connect_retries attempts must all still
7935 complete within the connection timeout period.
7937 The default is not to re-try if the first connection attempt fails.
7938 The (not recommended) maximum is 10 tries.
7940 A warning message will be generated if it is set to a too-high
7941 value and the configured value will be over-ridden.
7943 Note: These re-tries are in addition to forward_max_tries
7944 which limit how many different addresses may be tried to find
7948 NAME: retry_on_error
7950 LOC: Config.retry.onerror
7953 If set to ON Squid will automatically retry requests when
7954 receiving an error response with status 403 (Forbidden),
7955 500 (Internal Error), 501 or 503 (Service not available).
7956 Status 502 and 504 (Gateway errors) are always retried.
7958 This is mainly useful if you are in a complex cache hierarchy to
7959 work around access control errors.
7961 NOTE: This retry will attempt to find another working destination.
7962 Which is different from the server which just failed.
7965 NAME: as_whois_server
7967 LOC: Config.as_whois_server
7968 DEFAULT: whois.ra.net
7970 WHOIS server to query for AS numbers. NOTE: AS numbers are
7971 queried only when Squid starts up, not for every request.
7976 LOC: Config.onoff.offline
7979 Enable this option and Squid will never try to validate cached
7983 NAME: uri_whitespace
7984 TYPE: uri_whitespace
7985 LOC: Config.uri_whitespace
7988 What to do with requests that have whitespace characters in the
7991 strip: The whitespace characters are stripped out of the URL.
7992 This is the behavior recommended by RFC2396.
7993 deny: The request is denied. The user receives an "Invalid
7995 allow: The request is allowed and the URI is not changed. The
7996 whitespace characters remain in the URI. Note the
7997 whitespace is passed to redirector processes if they
7999 encode: The request is allowed and the whitespace characters are
8000 encoded according to RFC1738. This could be considered
8001 a violation of the HTTP/1.1
8002 RFC because proxies are not allowed to rewrite URI's.
8003 chop: The request is allowed and the URI is chopped at the
8004 first whitespace. This might also be considered a
8010 LOC: Config.chroot_dir
8013 Specifies a directory where Squid should do a chroot() while
8014 initializing. This also causes Squid to fully drop root
8015 privileges after initializing. This means, for example, if you
8016 use a HTTP port less than 1024 and try to reconfigure, you may
8017 get an error saying that Squid can not open the port.
8020 NAME: balance_on_multiple_ip
8022 LOC: Config.onoff.balance_on_multiple_ip
8025 Modern IP resolvers in squid sort lookup results by preferred access.
8026 By default squid will use these IP in order and only rotates to
8027 the next listed when the most preffered fails.
8029 Some load balancing servers based on round robin DNS have been
8030 found not to preserve user session state across requests
8031 to different IP addresses.
8033 Enabling this directive Squid rotates IP's per request.
8036 NAME: pipeline_prefetch
8038 LOC: Config.onoff.pipeline_prefetch
8041 To boost the performance of pipelined requests to closer
8042 match that of a non-proxied environment Squid can try to fetch
8043 up to two requests in parallel from a pipeline.
8045 Defaults to off for bandwidth management and access logging
8048 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
8051 NAME: high_response_time_warning
8054 LOC: Config.warnings.high_rptm
8057 If the one-minute median response time exceeds this value,
8058 Squid prints a WARNING with debug level 0 to get the
8059 administrators attention. The value is in milliseconds.
8062 NAME: high_page_fault_warning
8064 LOC: Config.warnings.high_pf
8067 If the one-minute average page fault rate exceeds this
8068 value, Squid prints a WARNING with debug level 0 to get
8069 the administrators attention. The value is in page faults
8073 NAME: high_memory_warning
8075 LOC: Config.warnings.high_memory
8078 If the memory usage (as determined by mallinfo) exceeds
8079 this amount, Squid prints a WARNING with debug level 0 to get
8080 the administrators attention.
8083 NAME: sleep_after_fork
8084 COMMENT: (microseconds)
8086 LOC: Config.sleep_after_fork
8089 When this is set to a non-zero value, the main Squid process
8090 sleeps the specified number of microseconds after a fork()
8091 system call. This sleep may help the situation where your
8092 system reports fork() failures due to lack of (virtual)
8093 memory. Note, however, if you have a lot of child
8094 processes, these sleep delays will add up and your
8095 Squid will not service requests for some amount of time
8096 until all the child processes have been started.
8097 On Windows value less then 1000 (1 milliseconds) are
8101 NAME: windows_ipaddrchangemonitor
8102 IFDEF: _SQUID_WINDOWS_
8106 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
8108 On Windows Squid by default will monitor IP address changes and will
8109 reconfigure itself after any detected event. This is very useful for
8110 proxies connected to internet with dial-up interfaces.
8111 In some cases (a Proxy server acting as VPN gateway is one) it could be
8112 desiderable to disable this behaviour setting this to 'off'.
8113 Note: after changing this, Squid service must be restarted.
8118 IFDEF: USE_SQUID_EUI
8120 LOC: Eui::TheConfig.euiLookup
8122 Whether to lookup the EUI or MAC address of a connected client.
8125 NAME: max_filedescriptors max_filedesc
8128 LOC: Config.max_filedescriptors
8130 The maximum number of filedescriptors supported.
8132 The default "0" means Squid inherits the current ulimit setting.
8134 Note: Changing this requires a restart of Squid. Also
8135 not all comm loops supports large values.
8143 Number of main Squid processes or "workers" to fork and maintain.
8144 0: "no daemon" mode, like running "squid -N ..."
8145 1: "no SMP" mode, start one main Squid process daemon (default)
8146 N: start N main Squid process daemons (i.e., SMP mode)
8148 In SMP mode, each worker does nearly all what a single Squid daemon
8149 does (e.g., listen on http_port and forward HTTP requests).
8152 NAME: cpu_affinity_map
8153 TYPE: CpuAffinityMap
8154 LOC: Config.cpuAffinityMap
8157 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
8159 Sets 1:1 mapping between Squid processes and CPU cores. For example,
8161 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
8163 affects processes 1 through 4 only and places them on the first
8164 four even cores, starting with core #1.
8166 CPU cores are numbered starting from 1. Requires support for
8167 sched_getaffinity(2) and sched_setaffinity(2) system calls.
8169 Multiple cpu_affinity_map options are merged.