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 with one of
252 the user does not exist.
255 An internal error occured in the helper, preventing
256 a result being identified.
258 "ERR" and "BH" results may optionally be followed by message="..."
259 containing a description available as %m in the returned error page.
261 If you use an authenticator, make sure you have 1 acl of type
264 By default, the basic authentication scheme is not used unless a
265 program is specified.
267 If you want to use the traditional NCSA proxy authentication, set
268 this line to something like
270 auth_param basic program @DEFAULT_PREFIX@/libexec/ncsa_auth @DEFAULT_PREFIX@/etc/passwd
273 HTTP uses iso-latin-1 as characterset, while some authentication
274 backends such as LDAP expects UTF-8. If this is set to on Squid will
275 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
276 username & password to the helper.
278 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
279 The maximum number of authenticator processes to spawn. If you start too few
280 Squid will have to wait for them to process a backlog of credential
281 verifications, slowing it down. When password verifications are
282 done via a (slow) network you are likely to need lots of
283 authenticator processes.
285 The startup= and idle= options permit some skew in the exact amount
286 run. A minimum of startup=N will begin during startup and reconfigure.
287 Squid will start more in groups of up to idle=N in an attempt to meet
288 traffic needs and to keep idle=N free above those traffic needs up to
291 The concurrency= option sets the number of concurrent requests the
292 helper can process. The default of 0 is used for helpers who only
293 supports one request at a time. Setting this to a number greater than
294 0 changes the protocol used to include a channel number first on the
295 request/response line, allowing multiple requests to be sent to the
296 same helper in parallell without wating for the response.
297 Must not be set unless it's known the helper supports this.
299 auth_param basic children 20 startup=0 idle=1
302 Specifies the realm name which is to be reported to the
303 client for the basic proxy authentication scheme (part of
304 the text the user will see when prompted their username and
305 password). There is no default.
306 auth_param basic realm Squid proxy-caching web server
308 "credentialsttl" timetolive
309 Specifies how long squid assumes an externally validated
310 username:password pair is valid for - in other words how
311 often the helper program is called for that user. Set this
312 low to force revalidation with short lived passwords. Note
313 setting this high does not impact your susceptibility
314 to replay attacks unless you are using an one-time password
315 system (such as SecureID). If you are using such a system,
316 you will be vulnerable to replay attacks unless you also
317 use the max_user_ip ACL in an http_access rule.
319 "casesensitive" on|off
320 Specifies if usernames are case sensitive. Most user databases are
321 case insensitive allowing the same username to be spelled using both
322 lower and upper case letters, but some are case sensitive. This
323 makes a big difference for user_max_ip ACL processing and similar.
324 auth_param basic casesensitive off
326 === Parameters for the digest scheme follow ===
329 Specify the command for the external authenticator. Such
330 a program reads a line containing "username":"realm" and
331 replies with one of three results:
334 the user exists. The ha1= key is mandatory and
335 contains the appropriate H(A1) value, hex encoded.
336 See rfc 2616 for the definition of H(A1).
339 the user does not exist.
342 An internal error occured in the helper, preventing
343 a result being identified.
345 "ERR" and "BH" results may optionally be followed by message="..."
346 containing a description available as %m in the returned error page.
348 By default, the digest authentication scheme is not used unless a
349 program is specified.
351 If you want to use a digest authenticator, set this line to
354 auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass
357 HTTP uses iso-latin-1 as characterset, while some authentication
358 backends such as LDAP expects UTF-8. If this is set to on Squid will
359 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
360 username & password to the helper.
362 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
363 The maximum number of authenticator processes to spawn (default 5).
364 If you start too few Squid will have to wait for them to
365 process a backlog of H(A1) calculations, slowing it down.
366 When the H(A1) calculations are done via a (slow) network
367 you are likely to need lots of authenticator processes.
369 The startup= and idle= options permit some skew in the exact amount
370 run. A minimum of startup=N will begin during startup and reconfigure.
371 Squid will start more in groups of up to idle=N in an attempt to meet
372 traffic needs and to keep idle=N free above those traffic needs up to
375 The concurrency= option sets the number of concurrent requests the
376 helper can process. The default of 0 is used for helpers who only
377 supports one request at a time. Setting this to a number greater than
378 0 changes the protocol used to include a channel number first on the
379 request/response line, allowing multiple requests to be sent to the
380 same helper in parallell without wating for the response.
381 Must not be set unless it's known the helper supports this.
383 auth_param digest children 20 startup=0 idle=1
386 Specifies the realm name which is to be reported to the
387 client for the digest proxy authentication scheme (part of
388 the text the user will see when prompted their username and
389 password). There is no default.
390 auth_param digest realm Squid proxy-caching web server
392 "nonce_garbage_interval" timeinterval
393 Specifies the interval that nonces that have been issued
394 to client_agent's are checked for validity.
396 "nonce_max_duration" timeinterval
397 Specifies the maximum length of time a given nonce will be
400 "nonce_max_count" number
401 Specifies the maximum number of times a given nonce can be
404 "nonce_strictness" on|off
405 Determines if squid requires strict increment-by-1 behavior
406 for nonce counts, or just incrementing (off - for use when
407 useragents generate nonce counts that occasionally miss 1
408 (ie, 1,2,4,6)). Default off.
410 "check_nonce_count" on|off
411 This directive if set to off can disable the nonce count check
412 completely to work around buggy digest qop implementations in
413 certain mainstream browser versions. Default on to check the
414 nonce count to protect from authentication replay attacks.
416 "post_workaround" on|off
417 This is a workaround to certain buggy browsers who sends
418 an incorrect request digest in POST requests when reusing
419 the same nonce as acquired earlier on a GET request.
421 === NTLM scheme options follow ===
424 Specify the command for the external NTLM authenticator.
425 Such a program reads exchanged NTLMSSP packets with
426 the browser via Squid until authentication is completed.
427 If you use an NTLM authenticator, make sure you have 1 acl
428 of type proxy_auth. By default, the NTLM authenticator program
431 auth_param ntlm program @DEFAULT_PREFIX@/bin/ntlm_auth
433 "children" numberofchildren [startup=N] [idle=N]
434 The maximum number of authenticator processes to spawn (default 5).
435 If you start too few Squid will have to wait for them to
436 process a backlog of credential verifications, slowing it
437 down. When credential verifications are done via a (slow)
438 network you are likely to need lots of authenticator
441 The startup= and idle= options permit some skew in the exact amount
442 run. A minimum of startup=N will begin during startup and reconfigure.
443 Squid will start more in groups of up to idle=N in an attempt to meet
444 traffic needs and to keep idle=N free above those traffic needs up to
447 auth_param ntlm children 20 startup=0 idle=1
450 If you experience problems with PUT/POST requests when using the
451 Negotiate authentication scheme then you can try setting this to
452 off. This will cause Squid to forcibly close the connection on
453 the initial requests where the browser asks which schemes are
454 supported by the proxy.
456 auth_param ntlm keep_alive on
458 === Options for configuring the NEGOTIATE auth-scheme follow ===
461 Specify the command for the external Negotiate authenticator.
462 This protocol is used in Microsoft Active-Directory enabled setups with
463 the Microsoft Internet Explorer or Mozilla Firefox browsers.
464 Its main purpose is to exchange credentials with the Squid proxy
465 using the Kerberos mechanisms.
466 If you use a Negotiate authenticator, make sure you have at least
467 one acl of type proxy_auth active. By default, the negotiate
468 authenticator program is not used.
469 The only supported program for this role is the ntlm_auth
470 program distributed as part of Samba, version 4 or later.
472 auth_param negotiate program @DEFAULT_PREFIX@/bin/ntlm_auth --helper-protocol=gss-spnego
474 "children" numberofchildren [startup=N] [idle=N]
475 The maximum number of authenticator processes to spawn (default 5).
476 If you start too few Squid will have to wait for them to
477 process a backlog of credential verifications, slowing it
478 down. When crendential verifications are done via a (slow)
479 network you are likely to need lots of authenticator
482 The startup= and idle= options permit some skew in the exact amount
483 run. A minimum of startup=N will begin during startup and reconfigure.
484 Squid will start more in groups of up to idle=N in an attempt to meet
485 traffic needs and to keep idle=N free above those traffic needs up to
488 auth_param negotiate children 20 startup=0 idle=1
491 If you experience problems with PUT/POST requests when using the
492 Negotiate authentication scheme then you can try setting this to
493 off. This will cause Squid to forcibly close the connection on
494 the initial requests where the browser asks which schemes are
495 supported by the proxy.
497 auth_param negotiate keep_alive on
502 #Recommended minimum configuration per scheme:
503 #auth_param negotiate program <uncomment and complete this line to activate>
504 #auth_param negotiate children 20 startup=0 idle=1
505 #auth_param negotiate keep_alive on
507 #auth_param ntlm program <uncomment and complete this line to activate>
508 #auth_param ntlm children 20 startup=0 idle=1
509 #auth_param ntlm keep_alive on
511 #auth_param digest program <uncomment and complete this line>
512 #auth_param digest children 20 startup=0 idle=1
513 #auth_param digest realm Squid proxy-caching web server
514 #auth_param digest nonce_garbage_interval 5 minutes
515 #auth_param digest nonce_max_duration 30 minutes
516 #auth_param digest nonce_max_count 50
518 #auth_param basic program <uncomment and complete this line>
519 #auth_param basic children 5 startup=5 idle=1
520 #auth_param basic realm Squid proxy-caching web server
521 #auth_param basic credentialsttl 2 hours
524 NAME: authenticate_cache_garbage_interval
527 LOC: Config.authenticateGCInterval
529 The time period between garbage collection across the username cache.
530 This is a tradeoff between memory utilization (long intervals - say
531 2 days) and CPU (short intervals - say 1 minute). Only change if you
535 NAME: authenticate_ttl
538 LOC: Config.authenticateTTL
540 The time a user & their credentials stay in the logged in
541 user cache since their last request. When the garbage
542 interval passes, all user credentials that have passed their
543 TTL are removed from memory.
546 NAME: authenticate_ip_ttl
548 LOC: Config.authenticateIpTTL
551 If you use proxy authentication and the 'max_user_ip' ACL,
552 this directive controls how long Squid remembers the IP
553 addresses associated with each user. Use a small value
554 (e.g., 60 seconds) if your users might change addresses
555 quickly, as is the case with dialups. You might be safe
556 using a larger value (e.g., 2 hours) in a corporate LAN
557 environment with relatively static address assignments.
562 -----------------------------------------------------------------------------
565 NAME: external_acl_type
566 TYPE: externalAclHelper
567 LOC: Config.externalAclHelperList
570 This option defines external acl classes using a helper program
571 to look up the status
573 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
577 ttl=n TTL in seconds for cached results (defaults to 3600
580 TTL for cached negative lookups (default same
583 Maximum number of acl helper processes spawned to service
584 external acl lookups of this type. (default 20)
586 Minimum number of acl helper processes to spawn during
587 startup and reconfigure to service external acl lookups
588 of this type. (default 0)
590 Number of acl helper processes to keep ahead of traffic
591 loads. Squid will spawn this many at once whenever load
592 rises above the capabilities of existing processes.
593 Up to the value of children-max. (default 1)
594 concurrency=n concurrency level per process. Only used with helpers
595 capable of processing more than one query at a time.
596 cache=n limit the result cache size, default is unbounded.
597 grace=n Percentage remaining of TTL where a refresh of a
598 cached entry should be initiated without needing to
599 wait for a new reply. (default is for no grace period)
600 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
601 ipv4 / ipv6 IP protocol used to communicate with this helper.
602 The default is to auto-detect IPv6 and use it when available.
604 FORMAT specifications
606 %LOGIN Authenticated user login name
607 %EXT_USER Username from previous external acl
608 %EXT_LOG Log details from previous external acl
609 %EXT_TAG Tag from previous external acl
610 %IDENT Ident user name
612 %SRCPORT Client source port
615 %PROTO Requested protocol
617 %PATH Requested URL path
618 %METHOD Request method
619 %MYADDR Squid interface address
620 %MYPORT Squid http_port number
621 %PATH Requested URL-path (including query-string if any)
622 %USER_CERT SSL User certificate in PEM format
623 %USER_CERTCHAIN SSL User certificate chain in PEM format
624 %USER_CERT_xx SSL User certificate subject attribute xx
625 %USER_CA_xx SSL User certificate issuer attribute xx
627 %>{Header} HTTP request header "Header"
629 HTTP request header "Hdr" list member "member"
631 HTTP request header list member using ; as
632 list separator. ; can be any non-alphanumeric
635 %<{Header} HTTP reply header "Header"
637 HTTP reply header "Hdr" list member "member"
639 HTTP reply header list member using ; as
640 list separator. ; can be any non-alphanumeric
643 %% The percent sign. Useful for helpers which need
644 an unchanging input format.
647 General request syntax:
649 [channel-ID] FORMAT-values [acl-values ...]
652 FORMAT-values consists of transaction details expanded with
653 whitespace separation per the config file FORMAT specification
654 using the FORMAT macros listed above.
656 acl-values consists of any string specified in the referencing
657 config 'acl ... external' line. see the "acl external" directive.
659 Request values sent to the helper are URL escaped to protect
660 each value in requests against whitespaces.
662 If using protocol=2.5 then the request sent to the helper is not
663 URL escaped to protect against whitespace.
665 NOTE: protocol=3.0 is deprecated as no longer necessary.
667 When using the concurrency= option the protocol is changed by
668 introducing a query channel tag in front of the request/response.
669 The query channel tag is a number between 0 and concurrency-1.
670 This value must be echoed back unchanged to Squid as the first part
671 of the response relating to its request.
674 The helper receives lines expanded per the above format specification
675 and for each input line returns 1 line starting with OK/ERR/BH result
676 code and optionally followed by additional keywords with more details.
679 General result syntax:
681 [channel-ID] result keyword=value ...
683 Result consists of one of the codes:
686 the ACL test produced a match.
689 the ACL test does not produce a match.
692 An internal error occured in the helper, preventing
693 a result being identified.
695 The meaning of 'a match' is determined by your squid.conf
696 access control configuration. See the Squid wiki for details.
700 user= The users name (login)
702 password= The users password (for login= cache_peer option)
704 message= Message describing the reason for this response.
705 Available as %o in error pages.
706 Useful on (ERR and BH results).
708 tag= Apply a tag to a request. Only sets a tag once,
709 does not alter existing tags.
711 log= String to be logged in access.log. Available as
712 %ea in logformat specifications.
714 Any keywords may be sent on any response whether OK, ERR or BH.
716 All response keyword values need to be a single token with URL
717 escaping, or enclosed in double quotes (") and escaped using \ on
718 any double quotes or \ characters within the value. The wrapping
719 double quotes are removed before the value is interpreted by Squid.
720 \r and \n are also replace by CR and LF.
722 Some example key values:
726 user="J. \"Bob\" Smith"
733 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
734 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
735 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
736 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
737 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
740 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
741 DEFAULT: localhost src 127.0.0.1/32 ::1
742 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
743 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
745 Defining an Access List
747 Every access list definition must begin with an aclname and acltype,
748 followed by either type-specific arguments or a quoted filename that
751 acl aclname acltype argument ...
752 acl aclname acltype "file" ...
754 When using "file", the file should contain one item per line.
756 By default, regular expressions are CASE-SENSITIVE.
757 To make them case-insensitive, use the -i option. To return case-sensitive
758 use the +i option between patterns, or make a new ACL line without -i.
760 Some acl types require suspending the current request in order
761 to access some external data source.
762 Those which do are marked with the tag [slow], those which
763 don't are marked as [fast].
764 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
765 for further information
767 ***** ACL TYPES AVAILABLE *****
769 acl aclname src ip-address/mask ... # clients IP address [fast]
770 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
771 acl aclname dst ip-address/mask ... # URL host's IP address [slow]
772 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
774 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
775 # The arp ACL requires the special configure option --enable-arp-acl.
776 # Furthermore, the ARP ACL code is not portable to all operating systems.
777 # It works on Linux, Solaris, Windows, FreeBSD, and some
778 # other *BSD variants.
781 # NOTE: Squid can only determine the MAC address for clients that are on
782 # the same subnet. If the client is on a different subnet,
783 # then Squid cannot find out its MAC address.
785 acl aclname srcdomain .foo.com ...
786 # reverse lookup, from client IP [slow]
787 acl aclname dstdomain .foo.com ...
788 # Destination server from URL [fast]
789 acl aclname srcdom_regex [-i] \.foo\.com ...
790 # regex matching client name [slow]
791 acl aclname dstdom_regex [-i] \.foo\.com ...
792 # regex matching server [fast]
794 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
795 # based URL is used and no match is found. The name "none" is used
796 # if the reverse lookup fails.
798 acl aclname src_as number ...
799 acl aclname dst_as number ...
801 # Except for access control, AS numbers can be used for
802 # routing of requests to specific caches. Here's an
803 # example for routing all requests for AS#1241 and only
804 # those to mycache.mydomain.net:
805 # acl asexample dst_as 1241
806 # cache_peer_access mycache.mydomain.net allow asexample
807 # cache_peer_access mycache_mydomain.net deny all
809 acl aclname peername myPeer ...
811 # match against a named cache_peer entry
812 # set unique name= on cache_peer lines for reliable use.
814 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
824 # h1:m1 must be less than h2:m2
826 acl aclname url_regex [-i] ^http:// ...
827 # regex matching on whole URL [fast]
828 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
829 # regex matching on URL login field
830 acl aclname urlpath_regex [-i] \.gif$ ...
831 # regex matching on URL path [fast]
833 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
835 acl aclname localport 3128 ... # TCP port the client connected to [fast]
836 # NP: for interception mode this is usually '80'
838 acl aclname myportname 3128 ... # http(s)_port name [fast]
840 acl aclname proto HTTP FTP ... # request protocol [fast]
842 acl aclname method GET POST ... # HTTP request method [fast]
844 acl aclname http_status 200 301 500- 400-403 ...
845 # status code in reply [fast]
847 acl aclname browser [-i] regexp ...
848 # pattern match on User-Agent header (see also req_header below) [fast]
850 acl aclname referer_regex [-i] regexp ...
851 # pattern match on Referer header [fast]
852 # Referer is highly unreliable, so use with care
854 acl aclname ident username ...
855 acl aclname ident_regex [-i] pattern ...
856 # string match on ident output [slow]
857 # use REQUIRED to accept any non-null ident.
859 acl aclname proxy_auth [-i] username ...
860 acl aclname proxy_auth_regex [-i] pattern ...
861 # perform http authentication challenge to the client and match against
862 # supplied credentials [slow]
864 # takes a list of allowed usernames.
865 # use REQUIRED to accept any valid username.
867 # Will use proxy authentication in forward-proxy scenarios, and plain
868 # http authenticaiton in reverse-proxy scenarios
870 # NOTE: when a Proxy-Authentication header is sent but it is not
871 # needed during ACL checking the username is NOT logged
874 # NOTE: proxy_auth requires a EXTERNAL authentication program
875 # to check username/password combinations (see
876 # auth_param directive).
878 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
879 # as the browser needs to be configured for using a proxy in order
880 # to respond to proxy authentication.
882 acl aclname snmp_community string ...
883 # A community string to limit access to your SNMP Agent [fast]
886 # acl snmppublic snmp_community public
888 acl aclname maxconn number
889 # This will be matched when the client's IP address has
890 # more than <number> TCP connections established. [fast]
891 # NOTE: This only measures direct TCP links so X-Forwarded-For
892 # indirect clients are not counted.
894 acl aclname max_user_ip [-s] number
895 # This will be matched when the user attempts to log in from more
896 # than <number> different ip addresses. The authenticate_ip_ttl
897 # parameter controls the timeout on the ip entries. [fast]
898 # If -s is specified the limit is strict, denying browsing
899 # from any further IP addresses until the ttl has expired. Without
900 # -s Squid will just annoy the user by "randomly" denying requests.
901 # (the counter is reset each time the limit is reached and a
903 # NOTE: in acceleration mode or where there is mesh of child proxies,
904 # clients may appear to come from multiple addresses if they are
905 # going through proxy farms, so a limit of 1 may cause user problems.
907 acl aclname random probability
908 # Pseudo-randomly match requests. Based on the probability given.
909 # Probability may be written as a decimal (0.333), fraction (1/3)
910 # or ratio of matches:non-matches (3:5).
912 acl aclname req_mime_type [-i] mime-type ...
913 # regex match against the mime type of the request generated
914 # by the client. Can be used to detect file upload or some
915 # types HTTP tunneling requests [fast]
916 # NOTE: This does NOT match the reply. You cannot use this
917 # to match the returned file type.
919 acl aclname req_header header-name [-i] any\.regex\.here
920 # regex match against any of the known request headers. May be
921 # thought of as a superset of "browser", "referer" and "mime-type"
924 acl aclname rep_mime_type [-i] mime-type ...
925 # regex match against the mime type of the reply received by
926 # squid. Can be used to detect file download or some
927 # types HTTP tunneling requests. [fast]
928 # NOTE: This has no effect in http_access rules. It only has
929 # effect in rules that affect the reply data stream such as
932 acl aclname rep_header header-name [-i] any\.regex\.here
933 # regex match against any of the known reply headers. May be
934 # thought of as a superset of "browser", "referer" and "mime-type"
937 acl aclname external class_name [arguments...]
938 # external ACL lookup via a helper class defined by the
939 # external_acl_type directive [slow]
941 acl aclname user_cert attribute values...
942 # match against attributes in a user SSL certificate
943 # attribute is one of DN/C/O/CN/L/ST [fast]
945 acl aclname ca_cert attribute values...
946 # match against attributes a users issuing CA SSL certificate
947 # attribute is one of DN/C/O/CN/L/ST [fast]
949 acl aclname ext_user username ...
950 acl aclname ext_user_regex [-i] pattern ...
951 # string match on username returned by external acl helper [slow]
952 # use REQUIRED to accept any non-null user name.
954 acl aclname tag tagvalue ...
955 # string match on tag returned by external acl helper [slow]
957 acl aclname hier_code codename ...
958 # string match against squid hierarchy code(s); [fast]
959 # e.g., DIRECT, PARENT_HIT, NONE, etc.
961 # NOTE: This has no effect in http_access rules. It only has
962 # effect in rules that affect the reply data stream such as
966 acl aclname ssl_error errorname
967 # match against SSL certificate validation error [fast]
969 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
972 # The following can be used as shortcuts for certificate properties:
973 # [ssl::]certHasExpired: the "not after" field is in the past
974 # [ssl::]certNotYetValid: the "not before" field is in the future
975 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
976 # [ssl::]certSelfSigned: The certificate is self signed.
977 # [ssl::]certDomainMismatch: The certificate CN domain does not
978 # match the name the name of the host we are connecting to.
980 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
981 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
982 # predefined ACLs, just like the 'all' ACL.
984 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
985 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
989 acl macaddress arp 09:00:2b:23:45:67
990 acl myexample dst_as 1241
991 acl password proxy_auth REQUIRED
992 acl fileupload req_mime_type -i ^multipart/form-data$
993 acl javascript rep_mime_type -i ^application/x-javascript$
997 # Recommended minimum configuration:
1000 # Example rule allowing access from your local networks.
1001 # Adapt to list your (internal) IP networks from where browsing
1003 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
1004 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
1005 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
1006 acl localnet src fc00::/7 # RFC 4193 local private network range
1007 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1009 acl SSL_ports port 443
1010 acl Safe_ports port 80 # http
1011 acl Safe_ports port 21 # ftp
1012 acl Safe_ports port 443 # https
1013 acl Safe_ports port 70 # gopher
1014 acl Safe_ports port 210 # wais
1015 acl Safe_ports port 1025-65535 # unregistered ports
1016 acl Safe_ports port 280 # http-mgmt
1017 acl Safe_ports port 488 # gss-http
1018 acl Safe_ports port 591 # filemaker
1019 acl Safe_ports port 777 # multiling http
1020 acl CONNECT method CONNECT
1024 NAME: follow_x_forwarded_for
1026 IFDEF: FOLLOW_X_FORWARDED_FOR
1027 LOC: Config.accessList.followXFF
1028 DEFAULT_IF_NONE: deny all
1030 Allowing or Denying the X-Forwarded-For header to be followed to
1031 find the original source of a request.
1033 Requests may pass through a chain of several other proxies
1034 before reaching us. The X-Forwarded-For header will contain a
1035 comma-separated list of the IP addresses in the chain, with the
1036 rightmost address being the most recent.
1038 If a request reaches us from a source that is allowed by this
1039 configuration item, then we consult the X-Forwarded-For header
1040 to see where that host received the request from. If the
1041 X-Forwarded-For header contains multiple addresses, we continue
1042 backtracking until we reach an address for which we are not allowed
1043 to follow the X-Forwarded-For header, or until we reach the first
1044 address in the list. For the purpose of ACL used in the
1045 follow_x_forwarded_for directive the src ACL type always matches
1046 the address we are testing and srcdomain matches its rDNS.
1048 The end result of this process is an IP address that we will
1049 refer to as the indirect client address. This address may
1050 be treated as the client address for access control, ICAP, delay
1051 pools and logging, depending on the acl_uses_indirect_client,
1052 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1053 log_uses_indirect_client and tproxy_uses_indirect_client options.
1055 This clause only supports fast acl types.
1056 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1058 SECURITY CONSIDERATIONS:
1060 Any host for which we follow the X-Forwarded-For header
1061 can place incorrect information in the header, and Squid
1062 will use the incorrect information as if it were the
1063 source address of the request. This may enable remote
1064 hosts to bypass any access control restrictions that are
1065 based on the client's source addresses.
1069 acl localhost src 127.0.0.1
1070 acl my_other_proxy srcdomain .proxy.example.com
1071 follow_x_forwarded_for allow localhost
1072 follow_x_forwarded_for allow my_other_proxy
1075 NAME: acl_uses_indirect_client
1078 IFDEF: FOLLOW_X_FORWARDED_FOR
1080 LOC: Config.onoff.acl_uses_indirect_client
1082 Controls whether the indirect client address
1083 (see follow_x_forwarded_for) is used instead of the
1084 direct client address in acl matching.
1086 NOTE: maxconn ACL considers direct TCP links and indirect
1087 clients will always have zero. So no match.
1090 NAME: delay_pool_uses_indirect_client
1093 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1095 LOC: Config.onoff.delay_pool_uses_indirect_client
1097 Controls whether the indirect client address
1098 (see follow_x_forwarded_for) is used instead of the
1099 direct client address in delay pools.
1102 NAME: log_uses_indirect_client
1105 IFDEF: FOLLOW_X_FORWARDED_FOR
1107 LOC: Config.onoff.log_uses_indirect_client
1109 Controls whether the indirect client address
1110 (see follow_x_forwarded_for) is used instead of the
1111 direct client address in the access log.
1114 NAME: tproxy_uses_indirect_client
1117 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1119 LOC: Config.onoff.tproxy_uses_indirect_client
1121 Controls whether the indirect client address
1122 (see follow_x_forwarded_for) is used instead of the
1123 direct client address when spoofing the outgoing client.
1125 This has no effect on requests arriving in non-tproxy
1128 SECURITY WARNING: Usage of this option is dangerous
1129 and should not be used trivially. Correct configuration
1130 of follow_x_forewarded_for with a limited set of trusted
1131 sources is required to prevent abuse of your proxy.
1136 LOC: Config.accessList.http
1137 DEFAULT_IF_NONE: deny all
1139 Allowing or Denying access based on defined access lists
1141 Access to the HTTP port:
1142 http_access allow|deny [!]aclname ...
1144 NOTE on default values:
1146 If there are no "access" lines present, the default is to deny
1149 If none of the "access" lines cause a match, the default is the
1150 opposite of the last line in the list. If the last line was
1151 deny, the default is allow. Conversely, if the last line
1152 is allow, the default will be deny. For these reasons, it is a
1153 good idea to have an "deny all" entry at the end of your access
1154 lists to avoid potential confusion.
1156 This clause supports both fast and slow acl types.
1157 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1162 # Recommended minimum Access Permission configuration:
1164 # Only allow cachemgr access from localhost
1165 http_access allow localhost manager
1166 http_access deny manager
1168 # Deny requests to certain unsafe ports
1169 http_access deny !Safe_ports
1171 # Deny CONNECT to other than secure SSL ports
1172 http_access deny CONNECT !SSL_ports
1174 # We strongly recommend the following be uncommented to protect innocent
1175 # web applications running on the proxy server who think the only
1176 # one who can access services on "localhost" is a local user
1177 #http_access deny to_localhost
1180 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1183 # Example rule allowing access from your local networks.
1184 # Adapt localnet in the ACL section to list your (internal) IP networks
1185 # from where browsing should be allowed
1186 http_access allow localnet
1187 http_access allow localhost
1189 # And finally deny all other access to this proxy
1190 http_access deny all
1194 NAME: adapted_http_access http_access2
1196 LOC: Config.accessList.adapted_http
1199 Allowing or Denying access based on defined access lists
1201 Essentially identical to http_access, but runs after redirectors
1202 and ICAP/eCAP adaptation. Allowing access control based on their
1205 If not set then only http_access is used.
1208 NAME: http_reply_access
1210 LOC: Config.accessList.reply
1213 Allow replies to client requests. This is complementary to http_access.
1215 http_reply_access allow|deny [!] aclname ...
1217 NOTE: if there are no access lines present, the default is to allow
1220 If none of the access lines cause a match the opposite of the
1221 last line will apply. Thus it is good practice to end the rules
1222 with an "allow all" or "deny all" entry.
1224 This clause supports both fast and slow acl types.
1225 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1230 LOC: Config.accessList.icp
1231 DEFAULT_IF_NONE: deny all
1233 Allowing or Denying access to the ICP port based on defined
1236 icp_access allow|deny [!]aclname ...
1238 See http_access for details
1240 This clause only supports fast acl types.
1241 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1243 # Allow ICP queries from local networks only
1244 #icp_access allow localnet
1245 #icp_access deny all
1251 LOC: Config.accessList.htcp
1252 DEFAULT_IF_NONE: deny all
1254 Allowing or Denying access to the HTCP port based on defined
1257 htcp_access allow|deny [!]aclname ...
1259 See http_access for details
1261 NOTE: The default if no htcp_access lines are present is to
1262 deny all traffic. This default may cause problems with peers
1263 using the htcp option.
1265 This clause only supports fast acl types.
1266 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1268 # Allow HTCP queries from local networks only
1269 #htcp_access allow localnet
1270 #htcp_access deny all
1273 NAME: htcp_clr_access
1276 LOC: Config.accessList.htcp_clr
1277 DEFAULT_IF_NONE: deny all
1279 Allowing or Denying access to purge content using HTCP based
1280 on defined access lists
1282 htcp_clr_access allow|deny [!]aclname ...
1284 See http_access for details
1286 This clause only supports fast acl types.
1287 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1289 # Allow HTCP CLR requests from trusted peers
1290 acl htcp_clr_peer src 172.16.1.2
1291 htcp_clr_access allow htcp_clr_peer
1296 LOC: Config.accessList.miss
1299 Determins whether network access is permitted when satisfying a request.
1302 to force your neighbors to use you as a sibling instead of
1305 acl localclients src 172.16.0.0/16
1306 miss_access allow localclients
1307 miss_access deny !localclients
1309 This means only your local clients are allowed to fetch relayed/MISS
1310 replies from the network and all other clients can only fetch cached
1314 The default for this setting allows all clients who passed the
1315 http_access rules to relay via this proxy.
1317 This clause only supports fast acl types.
1318 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1321 NAME: ident_lookup_access
1324 DEFAULT_IF_NONE: deny all
1325 LOC: Ident::TheConfig.identLookup
1327 A list of ACL elements which, if matched, cause an ident
1328 (RFC 931) lookup to be performed for this request. For
1329 example, you might choose to always perform ident lookups
1330 for your main multi-user Unix boxes, but not for your Macs
1331 and PCs. By default, ident lookups are not performed for
1334 To enable ident lookups for specific client addresses, you
1335 can follow this example:
1337 acl ident_aware_hosts src 198.168.1.0/24
1338 ident_lookup_access allow ident_aware_hosts
1339 ident_lookup_access deny all
1341 Only src type ACL checks are fully supported. A srcdomain
1342 ACL might work at times, but it will not always provide
1345 This clause only supports fast acl types.
1346 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1349 NAME: reply_body_max_size
1350 COMMENT: size [acl acl...]
1353 LOC: Config.ReplyBodySize
1355 This option specifies the maximum size of a reply body. It can be
1356 used to prevent users from downloading very large files, such as
1357 MP3's and movies. When the reply headers are received, the
1358 reply_body_max_size lines are processed, and the first line where
1359 all (if any) listed ACLs are true is used as the maximum body size
1362 This size is checked twice. First when we get the reply headers,
1363 we check the content-length value. If the content length value exists
1364 and is larger than the allowed size, the request is denied and the
1365 user receives an error message that says "the request or reply
1366 is too large." If there is no content-length, and the reply
1367 size exceeds this limit, the client's connection is just closed
1368 and they will receive a partial reply.
1370 WARNING: downstream caches probably can not detect a partial reply
1371 if there is no content-length header, so they will cache
1372 partial responses and give them out as hits. You should NOT
1373 use this option if you have downstream caches.
1375 WARNING: A maximum size smaller than the size of squid's error messages
1376 will cause an infinite loop and crash squid. Ensure that the smallest
1377 non-zero value you use is greater that the maximum header size plus
1378 the size of your largest error page.
1380 If you set this parameter none (the default), there will be
1383 Configuration Format is:
1384 reply_body_max_size SIZE UNITS [acl ...]
1386 reply_body_max_size 10 MB
1392 -----------------------------------------------------------------------------
1395 NAME: http_port ascii_port
1398 LOC: Config.Sockaddr.http
1400 Usage: port [mode] [options]
1401 hostname:port [mode] [options]
1402 1.2.3.4:port [mode] [options]
1404 The socket addresses where Squid will listen for HTTP client
1405 requests. You may specify multiple socket addresses.
1406 There are three forms: port alone, hostname with port, and
1407 IP address with port. If you specify a hostname or IP
1408 address, Squid binds the socket to that specific
1409 address. Most likely, you do not need to bind to a specific
1410 address, so you can use the port number alone.
1412 If you are running Squid in accelerator mode, you
1413 probably want to listen on port 80 also, or instead.
1415 The -a command line option may be used to specify additional
1416 port(s) where Squid listens for proxy request. Such ports will
1417 be plain proxy ports with no options.
1419 You may specify multiple socket addresses on multiple lines.
1423 intercept Support for IP-Layer interception of
1424 outgoing requests without browser settings.
1425 NP: disables authentication and IPv6 on the port.
1427 tproxy Support Linux TPROXY for spoofing outgoing
1428 connections using the client IP address.
1429 NP: disables authentication and maybe IPv6 on the port.
1431 accel Accelerator / reverse proxy mode
1433 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1434 establish secure connection with the client and with
1435 the server, decrypt HTTPS messages as they pass through
1436 Squid, and treat them as unencrypted HTTP messages,
1437 becoming the man-in-the-middle.
1439 The ssl_bump option is required to fully enable
1440 bumping of CONNECT requests.
1442 Omitting the mode flag causes default forward proxy mode to be used.
1445 Accelerator Mode Options:
1447 defaultsite=domainname
1448 What to use for the Host: header if it is not present
1449 in a request. Determines what site (not origin server)
1450 accelerators should consider the default.
1452 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1454 protocol= Protocol to reconstruct accelerated requests with.
1455 Defaults to http for http_port and https for
1458 vport Virtual host port support. Using the http_port number
1459 instead of the port passed on Host: headers.
1461 vport=NN Virtual host port support. Using the specified port
1462 number instead of the port passed on Host: headers.
1465 Act as if this Squid is the origin server.
1466 This currently means generate new Date: and Expires:
1467 headers on HIT instead of adding Age:.
1469 ignore-cc Ignore request Cache-Control headers.
1471 WARNING: This option violates HTTP specifications if
1472 used in non-accelerator setups.
1474 allow-direct Allow direct forwarding in accelerator mode. Normally
1475 accelerated requests are denied direct forwarding as if
1476 never_direct was used.
1478 WARNING: this option opens accelerator mode to security
1479 vulnerabilities usually only affecting in interception
1480 mode. Make sure to protect forwarding with suitable
1481 http_access rules when using this.
1484 SSL Bump Mode Options:
1485 In addition to these options ssl-bump requires TLS/SSL options.
1487 generate-host-certificates[=<on|off>]
1488 Dynamically create SSL server certificates for the
1489 destination hosts of bumped CONNECT requests.When
1490 enabled, the cert and key options are used to sign
1491 generated certificates. Otherwise generated
1492 certificate will be selfsigned.
1493 If there is a CA certificate lifetime of the generated
1494 certificate equals lifetime of the CA certificate. If
1495 generated certificate is selfsigned lifetime is three
1497 This option is enabled by default when ssl-bump is used.
1498 See the ssl-bump option above for more information.
1500 dynamic_cert_mem_cache_size=SIZE
1501 Approximate total RAM size spent on cached generated
1502 certificates. If set to zero, caching is disabled. The
1503 default value is 4MB.
1507 cert= Path to SSL certificate (PEM format).
1509 key= Path to SSL private key file (PEM format)
1510 if not specified, the certificate file is
1511 assumed to be a combined certificate and
1514 version= The version of SSL/TLS supported
1515 1 automatic (default)
1522 cipher= Colon separated list of supported ciphers.
1523 NOTE: some ciphers such as EDH ciphers depend on
1524 additional settings. If those settings are
1525 omitted the ciphers may be silently ignored
1526 by the OpenSSL library.
1528 options= Various SSL implementation options. The most important
1530 NO_SSLv2 Disallow the use of SSLv2
1531 NO_SSLv3 Disallow the use of SSLv3
1532 NO_TLSv1 Disallow the use of TLSv1.0
1533 NO_TLSv1_1 Disallow the use of TLSv1.1
1534 NO_TLSv1_2 Disallow the use of TLSv1.2
1535 SINGLE_DH_USE Always create a new key when using
1536 temporary/ephemeral DH key exchanges
1537 ALL Enable various bug workarounds
1538 suggested as "harmless" by OpenSSL
1539 Be warned that this reduces SSL/TLS
1540 strength to some attacks.
1541 See OpenSSL SSL_CTX_set_options documentation for a
1542 complete list of options.
1544 clientca= File containing the list of CAs to use when
1545 requesting a client certificate.
1547 cafile= File containing additional CA certificates to
1548 use when verifying client certificates. If unset
1549 clientca will be used.
1551 capath= Directory containing additional CA certificates
1552 and CRL lists to use when verifying client certificates.
1554 crlfile= File of additional CRL lists to use when verifying
1555 the client certificate, in addition to CRLs stored in
1556 the capath. Implies VERIFY_CRL flag below.
1558 dhparams= File containing DH parameters for temporary/ephemeral
1559 DH key exchanges. See OpenSSL documentation for details
1560 on how to create this file.
1561 WARNING: EDH ciphers will be silently disabled if this
1564 sslflags= Various flags modifying the use of SSL:
1566 Don't request client certificates
1567 immediately, but wait until acl processing
1568 requires a certificate (not yet implemented).
1570 Don't use the default CA lists built in
1573 Don't allow for session reuse. Each connection
1574 will result in a new SSL session.
1576 Verify CRL lists when accepting client
1579 Verify CRL lists for all certificates in the
1580 client certificate chain.
1582 sslcontext= SSL session ID context identifier.
1586 connection-auth[=on|off]
1587 use connection-auth=off to tell Squid to prevent
1588 forwarding Microsoft connection oriented authentication
1589 (NTLM, Negotiate and Kerberos)
1591 disable-pmtu-discovery=
1592 Control Path-MTU discovery usage:
1593 off lets OS decide on what to do (default).
1594 transparent disable PMTU discovery when transparent
1596 always disable always PMTU discovery.
1598 In many setups of transparently intercepting proxies
1599 Path-MTU discovery can not work on traffic towards the
1600 clients. This is the case when the intercepting device
1601 does not fully track connections and fails to forward
1602 ICMP must fragment messages to the cache server. If you
1603 have such setup and experience that certain clients
1604 sporadically hang or never complete requests set
1605 disable-pmtu-discovery option to 'transparent'.
1607 name= Specifies a internal name for the port. Defaults to
1608 the port specification (port or addr:port)
1610 tcpkeepalive[=idle,interval,timeout]
1611 Enable TCP keepalive probes of idle connections.
1612 In seconds; idle is the initial time before TCP starts
1613 probing the connection, interval how often to probe, and
1614 timeout the time before giving up.
1616 If you run Squid on a dual-homed machine with an internal
1617 and an external interface we recommend you to specify the
1618 internal address:port in http_port. This way Squid will only be
1619 visible on the internal address.
1623 # Squid normally listens to port 3128
1624 http_port @DEFAULT_HTTP_PORT@
1632 LOC: Config.Sockaddr.https
1634 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1636 The socket address where Squid will listen for client requests made
1637 over TLS or SSL connections. Commonly referred to as HTTPS.
1639 This is most useful for situations where you are running squid in
1640 accelerator mode and you want to do the SSL work at the accelerator level.
1642 You may specify multiple socket addresses on multiple lines,
1643 each with their own SSL certificate and/or options.
1647 accel Accelerator / reverse proxy mode
1649 intercept Support for IP-Layer interception of
1650 outgoing requests without browser settings.
1651 NP: disables authentication and IPv6 on the port.
1653 tproxy Support Linux TPROXY for spoofing outgoing
1654 connections using the client IP address.
1655 NP: disables authentication and maybe IPv6 on the port.
1657 ssl-bump For each intercepted connection allowed by ssl_bump
1658 ACLs, establish a secure connection with the client and with
1659 the server, decrypt HTTPS messages as they pass through
1660 Squid, and treat them as unencrypted HTTP messages,
1661 becoming the man-in-the-middle.
1663 An "ssl_bump server-first" match is required to
1664 fully enable bumping of intercepted SSL connections.
1666 Requires tproxy or intercept.
1668 Omitting the mode flag causes default forward proxy mode to be used.
1671 See http_port for a list of generic options
1676 cert= Path to SSL certificate (PEM format).
1678 key= Path to SSL private key file (PEM format)
1679 if not specified, the certificate file is
1680 assumed to be a combined certificate and
1683 version= The version of SSL/TLS supported
1684 1 automatic (default)
1689 cipher= Colon separated list of supported ciphers.
1691 options= Various SSL engine options. The most important
1693 NO_SSLv2 Disallow the use of SSLv2
1694 NO_SSLv3 Disallow the use of SSLv3
1695 NO_TLSv1 Disallow the use of TLSv1
1696 SINGLE_DH_USE Always create a new key when using
1697 temporary/ephemeral DH key exchanges
1698 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1699 documentation for a complete list of options.
1701 clientca= File containing the list of CAs to use when
1702 requesting a client certificate.
1704 cafile= File containing additional CA certificates to
1705 use when verifying client certificates. If unset
1706 clientca will be used.
1708 capath= Directory containing additional CA certificates
1709 and CRL lists to use when verifying client certificates.
1711 crlfile= File of additional CRL lists to use when verifying
1712 the client certificate, in addition to CRLs stored in
1713 the capath. Implies VERIFY_CRL flag below.
1715 dhparams= File containing DH parameters for temporary/ephemeral
1718 sslflags= Various flags modifying the use of SSL:
1720 Don't request client certificates
1721 immediately, but wait until acl processing
1722 requires a certificate (not yet implemented).
1724 Don't use the default CA lists built in
1727 Don't allow for session reuse. Each connection
1728 will result in a new SSL session.
1730 Verify CRL lists when accepting client
1733 Verify CRL lists for all certificates in the
1734 client certificate chain.
1736 sslcontext= SSL session ID context identifier.
1738 generate-host-certificates[=<on|off>]
1739 Dynamically create SSL server certificates for the
1740 destination hosts of bumped SSL requests.When
1741 enabled, the cert and key options are used to sign
1742 generated certificates. Otherwise generated
1743 certificate will be selfsigned.
1744 If there is CA certificate life time of generated
1745 certificate equals lifetime of CA certificate. If
1746 generated certificate is selfsigned lifetime is three
1748 This option is enabled by default when SslBump is used.
1749 See the sslBump option above for more information.
1751 dynamic_cert_mem_cache_size=SIZE
1752 Approximate total RAM size spent on cached generated
1753 certificates. If set to zero, caching is disabled. The
1754 default value is 4MB.
1756 See http_port for a list of available options.
1759 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1762 LOC: Ip::Qos::TheConfig.tosToServer
1764 Allows you to select a TOS/Diffserv value for packets outgoing
1765 on the server side, based on an ACL.
1767 tcp_outgoing_tos ds-field [!]aclname ...
1769 Example where normal_service_net uses the TOS value 0x00
1770 and good_service_net uses 0x20
1772 acl normal_service_net src 10.0.0.0/24
1773 acl good_service_net src 10.0.1.0/24
1774 tcp_outgoing_tos 0x00 normal_service_net
1775 tcp_outgoing_tos 0x20 good_service_net
1777 TOS/DSCP values really only have local significance - so you should
1778 know what you're specifying. For more information, see RFC2474,
1779 RFC2475, and RFC3260.
1781 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1782 "default" to use whatever default your host has. Note that in
1783 practice often only multiples of 4 is usable as the two rightmost bits
1784 have been redefined for use by ECN (RFC 3168 section 23.1).
1786 Processing proceeds in the order specified, and stops at first fully
1790 NAME: clientside_tos
1793 LOC: Ip::Qos::TheConfig.tosToClient
1795 Allows you to select a TOS/Diffserv value for packets being transmitted
1796 on the client-side, based on an ACL.
1798 clientside_tos ds-field [!]aclname ...
1800 Example where normal_service_net uses the TOS value 0x00
1801 and good_service_net uses 0x20
1803 acl normal_service_net src 10.0.0.0/24
1804 acl good_service_net src 10.0.1.0/24
1805 clientside_tos 0x00 normal_service_net
1806 clientside_tos 0x20 good_service_net
1808 Note: This feature is incompatible with qos_flows. Any TOS values set here
1809 will be overwritten by TOS values in qos_flows.
1812 NAME: tcp_outgoing_mark
1814 IFDEF: SO_MARK&&USE_LIBCAP
1816 LOC: Ip::Qos::TheConfig.nfmarkToServer
1818 Allows you to apply a Netfilter mark value to outgoing packets
1819 on the server side, based on an ACL.
1821 tcp_outgoing_mark mark-value [!]aclname ...
1823 Example where normal_service_net uses the mark value 0x00
1824 and good_service_net uses 0x20
1826 acl normal_service_net src 10.0.0.0/24
1827 acl good_service_net src 10.0.1.0/24
1828 tcp_outgoing_mark 0x00 normal_service_net
1829 tcp_outgoing_mark 0x20 good_service_net
1832 NAME: clientside_mark
1834 IFDEF: SO_MARK&&USE_LIBCAP
1836 LOC: Ip::Qos::TheConfig.nfmarkToClient
1838 Allows you to apply a Netfilter mark value to packets being transmitted
1839 on the client-side, based on an ACL.
1841 clientside_mark mark-value [!]aclname ...
1843 Example where normal_service_net uses the mark value 0x00
1844 and good_service_net uses 0x20
1846 acl normal_service_net src 10.0.0.0/24
1847 acl good_service_net src 10.0.1.0/24
1848 clientside_mark 0x00 normal_service_net
1849 clientside_mark 0x20 good_service_net
1851 Note: This feature is incompatible with qos_flows. Any mark values set here
1852 will be overwritten by mark values in qos_flows.
1859 LOC: Ip::Qos::TheConfig
1861 Allows you to select a TOS/DSCP value to mark outgoing
1862 connections with, based on where the reply was sourced. For
1863 platforms using netfilter, allows you to set a netfilter mark
1864 value instead of, or in addition to, a TOS value.
1866 TOS values really only have local significance - so you should
1867 know what you're specifying. For more information, see RFC2474,
1868 RFC2475, and RFC3260.
1870 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1871 in practice often only multiples of 4 is usable as the two rightmost bits
1872 have been redefined for use by ECN (RFC 3168 section 23.1).
1874 Mark values can be any unsigned 32-bit integer value.
1876 This setting is configured by setting the following values:
1878 tos|mark Whether to set TOS or netfilter mark values
1880 local-hit=0xFF Value to mark local cache hits.
1882 sibling-hit=0xFF Value to mark hits from sibling peers.
1884 parent-hit=0xFF Value to mark hits from parent peers.
1886 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
1887 over the preserve-miss feature (see below), unless
1888 mask is specified, in which case only the bits
1889 specified in the mask are written.
1891 The TOS variant of the following features are only possible on Linux
1892 and require your kernel to be patched with the TOS preserving ZPH
1893 patch, available from http://zph.bratcheda.org
1894 No patch is needed to preserve the netfilter mark, which will work
1895 with all variants of netfilter.
1897 disable-preserve-miss
1898 This option disables the preservation of the TOS or netfilter
1899 mark. By default, the existing TOS or netfilter mark value of
1900 the response coming from the remote server will be retained
1901 and masked with miss-mark.
1902 NOTE: in the case of a netfilter mark, the mark must be set on
1903 the connection (using the CONNMARK target) not on the packet
1907 Allows you to mask certain bits in the TOS or mark value
1908 received from the remote server, before copying the value to
1909 the TOS sent towards clients.
1910 Default for tos: 0xFF (TOS from server is not changed).
1911 Default for mark: 0xFFFFFFFF (mark from server is not changed).
1913 All of these features require the --enable-zph-qos compilation flag
1914 (enabled by default). Netfilter marking also requires the
1915 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
1916 libcap 2.09+ (--with-libcap).
1920 NAME: tcp_outgoing_address
1923 LOC: Config.accessList.outgoing_address
1925 Allows you to map requests to different outgoing IP addresses
1926 based on the username or source address of the user making
1929 tcp_outgoing_address ipaddr [[!]aclname] ...
1932 Forwarding clients with dedicated IPs for certain subnets.
1934 acl normal_service_net src 10.0.0.0/24
1935 acl good_service_net src 10.0.2.0/24
1937 tcp_outgoing_address 2001:db8::c001 good_service_net
1938 tcp_outgoing_address 10.1.0.2 good_service_net
1940 tcp_outgoing_address 2001:db8::beef normal_service_net
1941 tcp_outgoing_address 10.1.0.1 normal_service_net
1943 tcp_outgoing_address 2001:db8::1
1944 tcp_outgoing_address 10.1.0.3
1946 Processing proceeds in the order specified, and stops at first fully
1949 Squid will add an implicit IP version test to each line.
1950 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
1951 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
1954 NOTE: The use of this directive using client dependent ACLs is
1955 incompatible with the use of server side persistent connections. To
1956 ensure correct results it is best to set server_persistent_connections
1957 to off when using this directive in such configurations.
1959 NOTE: The use of this directive to set a local IP on outgoing TCP links
1960 is incompatible with using TPROXY to set client IP out outbound TCP links.
1961 When needing to contact peers use the no-tproxy cache_peer option and the
1962 client_dst_passthru directive re-enable normal forwarding such as this.
1966 NAME: host_verify_strict
1969 LOC: Config.onoff.hostStrictVerify
1971 Regardless of this option setting, when dealing with intercepted
1972 traffic, Squid always verifies that the destination IP address matches
1973 the Host header domain or IP (called 'authority form URL').
1975 This enforcement is performed to satisfy a MUST-level requirement in
1976 RFC 2616 section 14.23: "The Host field value MUST represent the naming
1977 authority of the origin server or gateway given by the original URL".
1980 Squid always responds with an HTTP 409 (Conflict) error
1981 page and logs a security warning if there is no match.
1983 Squid verifies that the destination IP address matches
1984 the Host header for forward-proxy and reverse-proxy traffic
1985 as well. For those traffic types, Squid also enables the
1986 following checks, comparing the corresponding Host header
1987 and Request-URI components:
1989 * The host names (domain or IP) must be identical,
1990 but valueless or missing Host header disables all checks.
1991 For the two host names to match, both must be either IP
1994 * Port numbers must be identical, but if a port is missing
1995 the scheme-default port is assumed.
1998 When set to OFF (the default):
1999 Squid allows suspicious requests to continue but logs a
2000 security warning and blocks caching of the response.
2002 * Forward-proxy traffic is not checked at all.
2004 * Reverse-proxy traffic is not checked at all.
2006 * Intercepted traffic which passes verification is handled
2007 according to client_dst_passthru.
2009 * Intercepted requests which fail verification are sent
2010 to the client original destination instead of DIRECT.
2011 This overrides 'client_dst_passthru off'.
2013 For now suspicious intercepted CONNECT requests are always
2014 responded to with an HTTP 409 (Conflict) error page.
2019 As described in CVE-2009-0801 when the Host: header alone is used
2020 to determine the destination of a request it becomes trivial for
2021 malicious scripts on remote websites to bypass browser same-origin
2022 security policy and sandboxing protections.
2024 The cause of this is that such applets are allowed to perform their
2025 own HTTP stack, in which case the same-origin policy of the browser
2026 sandbox only verifies that the applet tries to contact the same IP
2027 as from where it was loaded at the IP level. The Host: header may
2028 be different from the connected IP and approved origin.
2032 NAME: client_dst_passthru
2035 LOC: Config.onoff.client_dst_passthru
2037 With NAT or TPROXY intercepted traffic Squid may pass the request
2038 directly to the original client destination IP or seek a faster
2039 source using the HTTP Host header.
2041 Using Host to locate alternative servers can provide faster
2042 connectivity with a range of failure recovery options.
2043 But can also lead to connectivity trouble when the client and
2044 server are attempting stateful interactions unaware of the proxy.
2046 This option (on by default) prevents alternative DNS entries being
2047 located to send intercepted traffic DIRECT to an origin server.
2048 The clients original destination IP and port will be used instead.
2050 Regardless of this option setting, when dealing with intercepted
2051 traffic Squid will verify the Host: header and any traffic which
2052 fails Host verification will be treated as if this option were ON.
2054 see host_verify_strict for details on the verification process.
2059 -----------------------------------------------------------------------------
2062 NAME: ssl_unclean_shutdown
2066 LOC: Config.SSL.unclean_shutdown
2068 Some browsers (especially MSIE) bugs out on SSL shutdown
2075 LOC: Config.SSL.ssl_engine
2078 The OpenSSL engine to use. You will need to set this if you
2079 would like to use hardware SSL acceleration for example.
2082 NAME: sslproxy_client_certificate
2085 LOC: Config.ssl_client.cert
2088 Client SSL Certificate to use when proxying https:// URLs
2091 NAME: sslproxy_client_key
2094 LOC: Config.ssl_client.key
2097 Client SSL Key to use when proxying https:// URLs
2100 NAME: sslproxy_version
2103 LOC: Config.ssl_client.version
2106 SSL version level to use when proxying https:// URLs
2108 The versions of SSL/TLS supported:
2110 1 automatic (default)
2118 NAME: sslproxy_options
2121 LOC: Config.ssl_client.options
2124 SSL implementation options to use when proxying https:// URLs
2126 The most important being:
2128 NO_SSLv2 Disallow the use of SSLv2
2129 NO_SSLv3 Disallow the use of SSLv3
2130 NO_TLSv1 Disallow the use of TLSv1.0
2131 NO_TLSv1_1 Disallow the use of TLSv1.1
2132 NO_TLSv1_2 Disallow the use of TLSv1.2
2134 Always create a new key when using temporary/ephemeral
2137 Disable use of RFC5077 session tickets. Some servers
2138 may have problems understanding the TLS extension due
2139 to ambiguous specification in RFC4507.
2140 ALL Enable various bug workarounds suggested as "harmless"
2141 by OpenSSL. Be warned that this may reduce SSL/TLS
2142 strength to some attacks.
2144 See the OpenSSL SSL_CTX_set_options documentation for a
2145 complete list of possible options.
2148 NAME: sslproxy_cipher
2151 LOC: Config.ssl_client.cipher
2154 SSL cipher list to use when proxying https:// URLs
2156 Colon separated list of supported ciphers.
2159 NAME: sslproxy_cafile
2162 LOC: Config.ssl_client.cafile
2165 file containing CA certificates to use when verifying server
2166 certificates while proxying https:// URLs
2169 NAME: sslproxy_capath
2172 LOC: Config.ssl_client.capath
2175 directory containing CA certificates to use when verifying
2176 server certificates while proxying https:// URLs
2181 TYPE: sslproxy_ssl_bump
2182 LOC: Config.accessList.ssl_bump
2185 This option is consulted when a CONNECT request is received on
2186 an http_port (or a new connection is intercepted at an
2187 https_port), provided that port was configured with an ssl-bump
2188 flag. The subsequent data on the connection is either treated as
2189 HTTPS and decrypted OR tunneled at TCP level without decryption,
2190 depending on the first bumping "mode" which ACLs match.
2192 ssl_bump <mode> [!]acl ...
2194 The following bumping modes are supported:
2197 Allow bumping of the connection. Establish a secure connection
2198 with the client first, then connect to the server. This old mode
2199 does not allow Squid to mimic server SSL certificate and does
2200 not work with intercepted SSL connections.
2203 Allow bumping of the connection. Establish a secure connection
2204 with the server first, then establish a secure connection with
2205 the client, using a mimicked server certificate. Works with both
2206 CONNECT requests and intercepted SSL connections.
2209 Become a TCP tunnel without decoding the connection.
2210 Works with both CONNECT requests and intercepted SSL
2211 connections. This is the default behavior when no
2212 ssl_bump option is given or no ssl_bump ACLs match.
2214 By default, no connections are bumped.
2216 The first matching ssl_bump option wins. If no ACLs match, the
2217 connection is not bumped. Unlike most allow/deny ACL lists, ssl_bump
2218 does not have an implicit "negate the last given option" rule. You
2219 must make that rule explicit if you convert old ssl_bump allow/deny
2220 rules that rely on such an implicit rule.
2222 This clause supports both fast and slow acl types.
2223 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2225 See also: http_port ssl-bump, https_port ssl-bump
2228 # Example: Bump all requests except those originating from
2229 # localhost and those going to example.com.
2231 acl broken_sites dstdomain .example.com
2232 ssl_bump none localhost
2233 ssl_bump none broken_sites
2234 ssl_bump server-first all
2237 NAME: sslproxy_flags
2240 LOC: Config.ssl_client.flags
2243 Various flags modifying the use of SSL while proxying https:// URLs:
2244 DONT_VERIFY_PEER Accept certificates that fail verification.
2245 For refined control, see sslproxy_cert_error.
2246 NO_DEFAULT_CA Don't use the default CA list built in
2250 NAME: sslproxy_cert_error
2253 LOC: Config.ssl_client.cert_error
2256 Use this ACL to bypass server certificate validation errors.
2258 For example, the following lines will bypass all validation errors
2259 when talking to servers for example.com. All other
2260 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2262 acl BrokenButTrustedServers dstdomain example.com
2263 sslproxy_cert_error allow BrokenButTrustedServers
2264 sslproxy_cert_error deny all
2266 This clause only supports fast acl types.
2267 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2268 Using slow acl types may result in server crashes
2270 Without this option, all server certificate validation errors
2271 terminate the transaction. Bypassing validation errors is dangerous
2272 because an error usually implies that the server cannot be trusted and
2273 the connection may be insecure.
2275 See also: sslproxy_flags and DONT_VERIFY_PEER.
2277 Default setting: sslproxy_cert_error deny all
2280 NAME: sslproxy_cert_sign
2283 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2284 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2285 POSTSCRIPTUM: signTrusted all
2286 TYPE: sslproxy_cert_sign
2287 LOC: Config.ssl_client.cert_sign
2290 sslproxy_cert_sign <signing algorithm> acl ...
2292 The following certificate signing algorithms are supported:
2294 Sign using the configured CA certificate which is usually
2295 placed in and trusted by end-user browsers. This is the
2296 default for trusted origin server certificates.
2298 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2299 This is the default for untrusted origin server certificates
2300 that are not self-signed (see ssl::certUntrusted).
2302 Sign using a self-signed certificate with the right CN to
2303 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2304 browser. This is the default for self-signed origin server
2305 certificates (see ssl::certSelfSigned).
2307 This clause only supports fast acl types.
2309 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2310 signing algorithm to generate the certificate and ignores all
2311 subsequent sslproxy_cert_sign options (the first match wins). If no
2312 acl(s) match, the default signing algorithm is determined by errors
2313 detected when obtaining and validating the origin server certificate.
2315 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2316 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2317 CONNECT request that carries a domain name. In all other cases (CONNECT
2318 to an IP address or an intercepted SSL connection), Squid cannot detect
2319 the domain mismatch at certificate generation time when
2320 bump-server-first is used.
2323 NAME: sslproxy_cert_adapt
2326 TYPE: sslproxy_cert_adapt
2327 LOC: Config.ssl_client.cert_adapt
2330 sslproxy_cert_adapt <adaptation algorithm> acl ...
2332 The following certificate adaptation algorithms are supported:
2334 Sets the "Not After" property to the "Not After" property of
2335 the CA certificate used to sign generated certificates.
2337 Sets the "Not Before" property to the "Not Before" property of
2338 the CA certificate used to sign generated certificates.
2339 setCommonName or setCommonName{CN}
2340 Sets Subject.CN property to the host name specified as a
2341 CN parameter or, if no explicit CN parameter was specified,
2342 extracted from the CONNECT request. It is a misconfiguration
2343 to use setCommonName without an explicit parameter for
2344 intercepted or tproxied SSL connections.
2346 This clause only supports fast acl types.
2348 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2349 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2350 corresponding adaptation algorithm to generate the certificate and
2351 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2352 group (i.e., the first match wins within each algorithm group). If no
2353 acl(s) match, the default mimicking action takes place.
2355 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2356 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2357 CONNECT request that carries a domain name. In all other cases (CONNECT
2358 to an IP address or an intercepted SSL connection), Squid cannot detect
2359 the domain mismatch at certificate generation time when
2360 bump-server-first is used.
2363 NAME: sslpassword_program
2366 LOC: Config.Program.ssl_password
2369 Specify a program used for entering SSL key passphrases
2370 when using encrypted SSL certificate keys. If not specified
2371 keys must either be unencrypted, or Squid started with the -N
2372 option to allow it to query interactively for the passphrase.
2374 The key file name is given as argument to the program allowing
2375 selection of the right password if you have multiple encrypted
2380 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2381 -----------------------------------------------------------------------------
2384 NAME: sslcrtd_program
2387 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2388 LOC: Ssl::TheConfig.ssl_crtd
2390 Specify the location and options of the executable for ssl_crtd process.
2391 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2392 For more information use:
2393 @DEFAULT_SSL_CRTD@ -h
2396 NAME: sslcrtd_children
2397 TYPE: HelperChildConfig
2399 DEFAULT: 32 startup=5 idle=1
2400 LOC: Ssl::TheConfig.ssl_crtdChildren
2402 The maximum number of processes spawn to service ssl server.
2403 The maximum this may be safely set to is 32.
2405 The startup= and idle= options allow some measure of skew in your
2410 Sets the minimum number of processes to spawn when Squid
2411 starts or reconfigures. When set to zero the first request will
2412 cause spawning of the first child process to handle it.
2414 Starting too few children temporary slows Squid under load while it
2415 tries to spawn enough additional processes to cope with traffic.
2419 Sets a minimum of how many processes Squid is to try and keep available
2420 at all times. When traffic begins to rise above what the existing
2421 processes can handle this many more will be spawned up to the maximum
2422 configured. A minimum setting of 1 is required.
2424 You must have at least one ssl_crtd process.
2428 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2429 -----------------------------------------------------------------------------
2437 To specify other caches in a hierarchy, use the format:
2439 cache_peer hostname type http-port icp-port [options]
2444 # hostname type port port options
2445 # -------------------- -------- ----- ----- -----------
2446 cache_peer parent.foo.net parent 3128 3130 default
2447 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2448 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2449 cache_peer example.com parent 80 0 default
2450 cache_peer cdn.example.com sibling 3128 0
2452 type: either 'parent', 'sibling', or 'multicast'.
2454 proxy-port: The port number where the peer accept HTTP requests.
2455 For other Squid proxies this is usually 3128
2456 For web servers this is usually 80
2458 icp-port: Used for querying neighbor caches about objects.
2459 Set to 0 if the peer does not support ICP or HTCP.
2460 See ICP and HTCP options below for additional details.
2463 ==== ICP OPTIONS ====
2465 You MUST also set icp_port and icp_access explicitly when using these options.
2466 The defaults will prevent peer traffic using ICP.
2469 no-query Disable ICP queries to this neighbor.
2472 Indicates the named peer is a member of a multicast group.
2473 ICP queries will not be sent directly to the peer, but ICP
2474 replies will be accepted from it.
2476 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2477 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2480 To only send ICP queries to this neighbor infrequently.
2481 This is used to keep the neighbor round trip time updated
2482 and is usually used in conjunction with weighted-round-robin.
2485 ==== HTCP OPTIONS ====
2487 You MUST also set htcp_port and htcp_access explicitly when using these options.
2488 The defaults will prevent peer traffic using HTCP.
2491 htcp Send HTCP, instead of ICP, queries to the neighbor.
2492 You probably also want to set the "icp-port" to 4827
2493 instead of 3130. This directive accepts a comma separated
2494 list of options described below.
2496 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2498 htcp=no-clr Send HTCP to the neighbor but without
2499 sending any CLR requests. This cannot be used with
2502 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2503 This cannot be used with no-clr.
2506 Send HTCP to the neighbor including CLRs but only when
2507 they do not result from PURGE requests.
2510 Forward any HTCP CLR requests this proxy receives to the peer.
2513 ==== PEER SELECTION METHODS ====
2515 The default peer selection method is ICP, with the first responding peer
2516 being used as source. These options can be used for better load balancing.
2519 default This is a parent cache which can be used as a "last-resort"
2520 if a peer cannot be located by any of the peer-selection methods.
2521 If specified more than once, only the first is used.
2523 round-robin Load-Balance parents which should be used in a round-robin
2524 fashion in the absence of any ICP queries.
2525 weight=N can be used to add bias.
2527 weighted-round-robin
2528 Load-Balance parents which should be used in a round-robin
2529 fashion with the frequency of each parent being based on the
2530 round trip time. Closer parents are used more often.
2531 Usually used for background-ping parents.
2532 weight=N can be used to add bias.
2534 carp Load-Balance parents which should be used as a CARP array.
2535 The requests will be distributed among the parents based on the
2536 CARP load balancing hash function based on their weight.
2538 userhash Load-balance parents based on the client proxy_auth or ident username.
2540 sourcehash Load-balance parents based on the client source IP.
2543 To be used only for cache peers of type "multicast".
2544 ALL members of this multicast group have "sibling"
2545 relationship with it, not "parent". This is to a multicast
2546 group when the requested object would be fetched only from
2547 a "parent" cache, anyway. It's useful, e.g., when
2548 configuring a pool of redundant Squid proxies, being
2549 members of the same multicast group.
2552 ==== PEER SELECTION OPTIONS ====
2554 weight=N use to affect the selection of a peer during any weighted
2555 peer-selection mechanisms.
2556 The weight must be an integer; default is 1,
2557 larger weights are favored more.
2558 This option does not affect parent selection if a peering
2559 protocol is not in use.
2561 basetime=N Specify a base amount to be subtracted from round trip
2563 It is subtracted before division by weight in calculating
2564 which parent to fectch from. If the rtt is less than the
2565 base time the rtt is set to a minimal value.
2567 ttl=N Specify a TTL to use when sending multicast ICP queries
2569 Only useful when sending to a multicast group.
2570 Because we don't accept ICP replies from random
2571 hosts, you must configure other group members as
2572 peers with the 'multicast-responder' option.
2574 no-delay To prevent access to this neighbor from influencing the
2577 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2578 enabled) for this host from the specified URL rather
2579 than the Squid default location.
2582 ==== CARP OPTIONS ====
2584 carp-key=key-specification
2585 use a different key than the full URL to hash against the peer.
2586 the key-specification is a comma-separated list of the keywords
2587 scheme, host, port, path, params
2588 Order is not important.
2590 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2592 originserver Causes this parent to be contacted as an origin server.
2593 Meant to be used in accelerator setups when the peer
2597 Set the Host header of requests forwarded to this peer.
2598 Useful in accelerator setups where the server (peer)
2599 expects a certain domain name but clients may request
2600 others. ie example.com or www.example.com
2602 no-digest Disable request of cache digests.
2605 Disables requesting ICMP RTT database (NetDB).
2608 ==== AUTHENTICATION OPTIONS ====
2611 If this is a personal/workgroup proxy and your parent
2612 requires proxy authentication.
2614 Note: The string can include URL escapes (i.e. %20 for
2615 spaces). This also means % must be written as %%.
2618 Send login details received from client to this peer.
2619 Both Proxy- and WWW-Authorization headers are passed
2620 without alteration to the peer.
2621 Authentication is not required by Squid for this to work.
2623 Note: This will pass any form of authentication but
2624 only Basic auth will work through a proxy unless the
2625 connection-auth options are also used.
2627 login=PASS Send login details received from client to this peer.
2628 Authentication is not required by this option.
2630 If there are no client-provided authentication headers
2631 to pass on, but username and password are available
2632 from an external ACL user= and password= result tags
2633 they may be sent instead.
2635 Note: To combine this with proxy_auth both proxies must
2636 share the same user database as HTTP only allows for
2637 a single login (one for proxy, one for origin server).
2638 Also be warned this will expose your users proxy
2639 password to the peer. USE WITH CAUTION
2642 Send the username to the upstream cache, but with a
2643 fixed password. This is meant to be used when the peer
2644 is in another administrative domain, but it is still
2645 needed to identify each user.
2646 The star can optionally be followed by some extra
2647 information which is added to the username. This can
2648 be used to identify this proxy to the peer, similar to
2649 the login=username:password option above.
2652 If this is a personal/workgroup proxy and your parent
2653 requires a secure proxy authentication.
2654 The first principal from the default keytab or defined by
2655 the environment variable KRB5_KTNAME will be used.
2657 WARNING: The connection may transmit requests from multiple
2658 clients. Negotiate often assumes end-to-end authentication
2659 and a single-client. Which is not strictly true here.
2661 login=NEGOTIATE:principal_name
2662 If this is a personal/workgroup proxy and your parent
2663 requires a secure proxy authentication.
2664 The principal principal_name from the default keytab or
2665 defined by the environment variable KRB5_KTNAME will be
2668 WARNING: The connection may transmit requests from multiple
2669 clients. Negotiate often assumes end-to-end authentication
2670 and a single-client. Which is not strictly true here.
2672 connection-auth=on|off
2673 Tell Squid that this peer does or not support Microsoft
2674 connection oriented authentication, and any such
2675 challenges received from there should be ignored.
2676 Default is auto to automatically determine the status
2680 ==== SSL / HTTPS / TLS OPTIONS ====
2682 ssl Encrypt connections to this peer with SSL/TLS.
2684 sslcert=/path/to/ssl/certificate
2685 A client SSL certificate to use when connecting to
2688 sslkey=/path/to/ssl/key
2689 The private SSL key corresponding to sslcert above.
2690 If 'sslkey' is not specified 'sslcert' is assumed to
2691 reference a combined file containing both the
2692 certificate and the key.
2694 sslversion=1|2|3|4|5|6
2695 The SSL version to use when connecting to this peer
2696 1 = automatic (default)
2703 sslcipher=... The list of valid SSL ciphers to use when connecting
2706 ssloptions=... Specify various SSL implementation options:
2708 NO_SSLv2 Disallow the use of SSLv2
2709 NO_SSLv3 Disallow the use of SSLv3
2710 NO_TLSv1 Disallow the use of TLSv1.0
2711 NO_TLSv1_1 Disallow the use of TLSv1.1
2712 NO_TLSv1_2 Disallow the use of TLSv1.2
2714 Always create a new key when using
2715 temporary/ephemeral DH key exchanges
2716 ALL Enable various bug workarounds
2717 suggested as "harmless" by OpenSSL
2718 Be warned that this reduces SSL/TLS
2719 strength to some attacks.
2721 See the OpenSSL SSL_CTX_set_options documentation for a
2724 sslcafile=... A file containing additional CA certificates to use
2725 when verifying the peer certificate.
2727 sslcapath=... A directory containing additional CA certificates to
2728 use when verifying the peer certificate.
2730 sslcrlfile=... A certificate revocation list file to use when
2731 verifying the peer certificate.
2733 sslflags=... Specify various flags modifying the SSL implementation:
2736 Accept certificates even if they fail to
2739 Don't use the default CA list built in
2742 Don't verify the peer certificate
2743 matches the server name
2745 ssldomain= The peer name as advertised in it's certificate.
2746 Used for verifying the correctness of the received peer
2747 certificate. If not specified the peer hostname will be
2751 Enable the "Front-End-Https: On" header needed when
2752 using Squid as a SSL frontend in front of Microsoft OWA.
2753 See MS KB document Q307347 for details on this header.
2754 If set to auto the header will only be added if the
2755 request is forwarded as a https:// URL.
2758 ==== GENERAL OPTIONS ====
2761 A peer-specific connect timeout.
2762 Also see the peer_connect_timeout directive.
2764 connect-fail-limit=N
2765 How many times connecting to a peer must fail before
2766 it is marked as down. Default is 10.
2768 allow-miss Disable Squid's use of only-if-cached when forwarding
2769 requests to siblings. This is primarily useful when
2770 icp_hit_stale is used by the sibling. To extensive use
2771 of this option may result in forwarding loops, and you
2772 should avoid having two-way peerings with this option.
2773 For example to deny peer usage on requests from peer
2774 by denying cache_peer_access if the source is a peer.
2776 max-conn=N Limit the amount of connections Squid may open to this
2779 name=xxx Unique name for the peer.
2780 Required if you have multiple peers on the same host
2781 but different ports.
2782 This name can be used in cache_peer_access and similar
2783 directives to dentify the peer.
2784 Can be used by outgoing access controls through the
2787 no-tproxy Do not use the client-spoof TPROXY support when forwarding
2788 requests to this peer. Use normal address selection instead.
2790 proxy-only objects fetched from the peer will not be stored locally.
2794 NAME: cache_peer_domain cache_host_domain
2799 Use to limit the domains for which a neighbor cache will be
2802 cache_peer_domain cache-host domain [domain ...]
2803 cache_peer_domain cache-host !domain
2805 For example, specifying
2807 cache_peer_domain parent.foo.net .edu
2809 has the effect such that UDP query packets are sent to
2810 'bigserver' only when the requested object exists on a
2811 server in the .edu domain. Prefixing the domainname
2812 with '!' means the cache will be queried for objects
2815 NOTE: * Any number of domains may be given for a cache-host,
2816 either on the same or separate lines.
2817 * When multiple domains are given for a particular
2818 cache-host, the first matched domain is applied.
2819 * Cache hosts with no domain restrictions are queried
2821 * There are no defaults.
2822 * There is also a 'cache_peer_access' tag in the ACL
2826 NAME: cache_peer_access
2831 Similar to 'cache_peer_domain' but provides more flexibility by
2834 cache_peer_access cache-host allow|deny [!]aclname ...
2836 The syntax is identical to 'http_access' and the other lists of
2837 ACL elements. See the comments for 'http_access' below, or
2838 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
2841 NAME: neighbor_type_domain
2842 TYPE: hostdomaintype
2846 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
2848 Modifying the neighbor type for specific domains is now
2849 possible. You can treat some domains differently than the
2850 default neighbor type specified on the 'cache_peer' line.
2851 Normally it should only be necessary to list domains which
2852 should be treated differently because the default neighbor type
2853 applies for hostnames which do not match domains listed here.
2856 cache_peer cache.foo.org parent 3128 3130
2857 neighbor_type_domain cache.foo.org sibling .com .net
2858 neighbor_type_domain cache.foo.org sibling .au .de
2861 NAME: dead_peer_timeout
2865 LOC: Config.Timeout.deadPeer
2867 This controls how long Squid waits to declare a peer cache
2868 as "dead." If there are no ICP replies received in this
2869 amount of time, Squid will declare the peer dead and not
2870 expect to receive any further ICP replies. However, it
2871 continues to send ICP queries, and will mark the peer as
2872 alive upon receipt of the first subsequent ICP reply.
2874 This timeout also affects when Squid expects to receive ICP
2875 replies from peers. If more than 'dead_peer' seconds have
2876 passed since the last ICP reply was received, Squid will not
2877 expect to receive an ICP reply on the next query. Thus, if
2878 your time between requests is greater than this timeout, you
2879 will see a lot of requests sent DIRECT to origin servers
2880 instead of to your parents.
2883 NAME: forward_max_tries
2886 LOC: Config.forward_max_tries
2888 Controls how many different forward paths Squid will try
2889 before giving up. See also forward_timeout.
2891 NOTE: connect_retries (default: none) can make each of these
2892 possible forwarding paths be tried multiple times.
2895 NAME: hierarchy_stoplist
2898 LOC: Config.hierarchy_stoplist
2900 A list of words which, if found in a URL, cause the object to
2901 be handled directly by this cache. In other words, use this
2902 to not query neighbor caches for certain objects. You may
2903 list this option multiple times.
2906 hierarchy_stoplist cgi-bin ?
2908 Note: never_direct overrides this option.
2912 MEMORY CACHE OPTIONS
2913 -----------------------------------------------------------------------------
2920 LOC: Config.memMaxSize
2922 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
2923 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
2924 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
2925 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
2927 'cache_mem' specifies the ideal amount of memory to be used
2929 * In-Transit objects
2931 * Negative-Cached objects
2933 Data for these objects are stored in 4 KB blocks. This
2934 parameter specifies the ideal upper limit on the total size of
2935 4 KB blocks allocated. In-Transit objects take the highest
2938 In-transit objects have priority over the others. When
2939 additional space is needed for incoming data, negative-cached
2940 and hot objects will be released. In other words, the
2941 negative-cached and hot objects will fill up any unused space
2942 not needed for in-transit objects.
2944 If circumstances require, this limit will be exceeded.
2945 Specifically, if your incoming request rate requires more than
2946 'cache_mem' of memory to hold in-transit objects, Squid will
2947 exceed this limit to satisfy the new requests. When the load
2948 decreases, blocks will be freed until the high-water mark is
2949 reached. Thereafter, blocks will be used to store hot
2952 If shared memory caching is enabled, Squid does not use the shared
2953 cache space for in-transit objects, but they still consume as much
2954 local memory as they need. For more details about the shared memory
2955 cache, see memory_cache_shared.
2958 NAME: maximum_object_size_in_memory
2962 LOC: Config.Store.maxInMemObjSize
2964 Objects greater than this size will not be attempted to kept in
2965 the memory cache. This should be set high enough to keep objects
2966 accessed frequently in memory to improve performance whilst low
2967 enough to keep larger objects from hoarding cache_mem.
2970 NAME: memory_cache_shared
2973 LOC: Config.memShared
2975 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
2977 Controls whether the memory cache is shared among SMP workers.
2979 The shared memory cache is meant to occupy cache_mem bytes and replace
2980 the non-shared memory cache, although some entities may still be
2981 cached locally by workers for now (e.g., internal and in-transit
2982 objects may be served from a local memory cache even if shared memory
2983 caching is enabled).
2985 By default, the memory cache is shared if and only if all of the
2986 following conditions are satisfied: Squid runs in SMP mode with
2987 multiple workers, cache_mem is positive, and Squid environment
2988 supports required IPC primitives (e.g., POSIX shared memory segments
2989 and GCC-style atomic operations).
2991 To avoid blocking locks, shared memory uses opportunistic algorithms
2992 that do not guarantee that every cachable entity that could have been
2993 shared among SMP workers will actually be shared.
2995 Currently, entities exceeding 32KB in size cannot be shared.
2998 NAME: memory_cache_mode
3003 Controls which objects to keep in the memory cache (cache_mem)
3005 always Keep most recently fetched objects in memory (default)
3007 disk Only disk cache hits are kept in memory, which means
3008 an object must first be cached on disk and then hit
3009 a second time before cached in memory.
3011 network Only objects fetched from network is kept in memory
3014 NAME: memory_replacement_policy
3016 LOC: Config.memPolicy
3019 The memory replacement policy parameter determines which
3020 objects are purged from memory when memory space is needed.
3022 See cache_replacement_policy for details.
3027 -----------------------------------------------------------------------------
3030 NAME: cache_replacement_policy
3032 LOC: Config.replPolicy
3035 The cache replacement policy parameter determines which
3036 objects are evicted (replaced) when disk space is needed.
3038 lru : Squid's original list based LRU policy
3039 heap GDSF : Greedy-Dual Size Frequency
3040 heap LFUDA: Least Frequently Used with Dynamic Aging
3041 heap LRU : LRU policy implemented using a heap
3043 Applies to any cache_dir lines listed below this.
3045 The LRU policies keeps recently referenced objects.
3047 The heap GDSF policy optimizes object hit rate by keeping smaller
3048 popular objects in cache so it has a better chance of getting a
3049 hit. It achieves a lower byte hit rate than LFUDA though since
3050 it evicts larger (possibly popular) objects.
3052 The heap LFUDA policy keeps popular objects in cache regardless of
3053 their size and thus optimizes byte hit rate at the expense of
3054 hit rate since one large, popular object will prevent many
3055 smaller, slightly less popular objects from being cached.
3057 Both policies utilize a dynamic aging mechanism that prevents
3058 cache pollution that can otherwise occur with frequency-based
3059 replacement policies.
3061 NOTE: if using the LFUDA replacement policy you should increase
3062 the value of maximum_object_size above its default of 4096 KB to
3063 to maximize the potential byte hit rate improvement of LFUDA.
3065 For more information about the GDSF and LFUDA cache replacement
3066 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3067 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3073 LOC: Config.cacheSwap
3077 cache_dir Type Directory-Name Fs-specific-data [options]
3079 You can specify multiple cache_dir lines to spread the
3080 cache among different disk partitions.
3082 Type specifies the kind of storage system to use. Only "ufs"
3083 is built by default. To enable any of the other storage systems
3084 see the --enable-storeio configure option.
3086 'Directory' is a top-level directory where cache swap
3087 files will be stored. If you want to use an entire disk
3088 for caching, this can be the mount-point directory.
3089 The directory must exist and be writable by the Squid
3090 process. Squid will NOT create this directory for you.
3092 In SMP configurations, cache_dir must not precede the workers option
3093 and should use configuration macros or conditionals to give each
3094 worker interested in disk caching a dedicated cache directory.
3098 "ufs" is the old well-known Squid storage format that has always
3101 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3103 'Mbytes' is the amount of disk space (MB) to use under this
3104 directory. The default is 100 MB. Change this to suit your
3105 configuration. Do NOT put the size of your disk drive here.
3106 Instead, if you want Squid to use the entire disk drive,
3107 subtract 20% and use that value.
3109 'L1' is the number of first-level subdirectories which
3110 will be created under the 'Directory'. The default is 16.
3112 'L2' is the number of second-level subdirectories which
3113 will be created under each first-level directory. The default
3116 The aufs store type:
3118 "aufs" uses the same storage format as "ufs", utilizing
3119 POSIX-threads to avoid blocking the main Squid process on
3120 disk-I/O. This was formerly known in Squid as async-io.
3122 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3124 see argument descriptions under ufs above
3126 The diskd store type:
3128 "diskd" uses the same storage format as "ufs", utilizing a
3129 separate process to avoid blocking the main Squid process on
3132 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3134 see argument descriptions under ufs above
3136 Q1 specifies the number of unacknowledged I/O requests when Squid
3137 stops opening new files. If this many messages are in the queues,
3138 Squid won't open new files. Default is 64
3140 Q2 specifies the number of unacknowledged messages when Squid
3141 starts blocking. If this many messages are in the queues,
3142 Squid blocks until it receives some replies. Default is 72
3144 When Q1 < Q2 (the default), the cache directory is optimized
3145 for lower response time at the expense of a decrease in hit
3146 ratio. If Q1 > Q2, the cache directory is optimized for
3147 higher hit ratio at the expense of an increase in response
3150 The rock store type:
3152 cache_dir rock Directory-Name Mbytes <max-size=bytes> [options]
3154 The Rock Store type is a database-style storage. All cached
3155 entries are stored in a "database" file, using fixed-size slots,
3156 one entry per slot. The database size is specified in MB. The
3157 slot size is specified in bytes using the max-size option. See
3158 below for more info on the max-size option.
3160 swap-timeout=msec: Squid will not start writing a miss to or
3161 reading a hit from disk if it estimates that the swap operation
3162 will take more than the specified number of milliseconds. By
3163 default and when set to zero, disables the disk I/O time limit
3164 enforcement. Ignored when using blocking I/O module because
3165 blocking synchronous I/O does not allow Squid to estimate the
3166 expected swap wait time.
3168 max-swap-rate=swaps/sec: Artificially limits disk access using
3169 the specified I/O rate limit. Swap out requests that
3170 would cause the average I/O rate to exceed the limit are
3171 delayed. Individual swap in requests (i.e., hits or reads) are
3172 not delayed, but they do contribute to measured swap rate and
3173 since they are placed in the same FIFO queue as swap out
3174 requests, they may wait longer if max-swap-rate is smaller.
3175 This is necessary on file systems that buffer "too
3176 many" writes and then start blocking Squid and other processes
3177 while committing those writes to disk. Usually used together
3178 with swap-timeout to avoid excessive delays and queue overflows
3179 when disk demand exceeds available disk "bandwidth". By default
3180 and when set to zero, disables the disk I/O rate limit
3181 enforcement. Currently supported by IpcIo module only.
3184 The coss store type:
3186 NP: COSS filesystem in Squid-3 has been deemed too unstable for
3187 production use and has thus been removed from this release.
3188 We hope that it can be made usable again soon.
3190 block-size=n defines the "block size" for COSS cache_dir's.
3191 Squid uses file numbers as block numbers. Since file numbers
3192 are limited to 24 bits, the block size determines the maximum
3193 size of the COSS partition. The default is 512 bytes, which
3194 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
3195 you should not change the coss block size after Squid
3196 has written some objects to the cache_dir.
3198 The coss file store has changed from 2.5. Now it uses a file
3199 called 'stripe' in the directory names in the config - and
3200 this will be created by squid -z.
3204 no-store, no new objects should be stored to this cache_dir
3206 min-size=n, refers to the min object size in bytes this cache_dir
3207 will accept. It's used to restrict a cache_dir to only store
3208 large objects (e.g. aufs) while other storedirs are optimized
3209 for smaller objects (e.g. COSS). Defaults to 0.
3211 max-size=n, refers to the max object size in bytes this cache_dir
3212 supports. It is used to select the cache_dir to store the object.
3213 Note: To make optimal use of the max-size limits you should order
3214 the cache_dir lines with the smallest max-size value first and the
3215 ones with no max-size specification last.
3217 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
3218 which can be changed with the --with-coss-membuf-size=N configure
3222 # Uncomment and adjust the following to add a disk cache directory.
3223 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3227 NAME: store_dir_select_algorithm
3229 LOC: Config.store_dir_select_algorithm
3232 Set this to 'round-robin' as an alternative.
3235 NAME: max_open_disk_fds
3237 LOC: Config.max_open_disk_fds
3240 To avoid having disk as the I/O bottleneck Squid can optionally
3241 bypass the on-disk cache if more than this amount of disk file
3242 descriptors are open.
3244 A value of 0 indicates no limit.
3247 NAME: minimum_object_size
3251 LOC: Config.Store.minObjectSize
3253 Objects smaller than this size will NOT be saved on disk. The
3254 value is specified in kilobytes, and the default is 0 KB, which
3255 means there is no minimum.
3258 NAME: maximum_object_size
3262 LOC: Config.Store.maxObjectSize
3264 Objects larger than this size will NOT be saved on disk. The
3265 value is specified in kilobytes, and the default is 4MB. If
3266 you wish to get a high BYTES hit ratio, you should probably
3267 increase this (one 32 MB object hit counts for 3200 10KB
3268 hits). If you wish to increase speed more than your want to
3269 save bandwidth you should leave this low.
3271 NOTE: if using the LFUDA replacement policy you should increase
3272 this value to maximize the byte hit rate improvement of LFUDA!
3273 See replacement_policy below for a discussion of this policy.
3276 NAME: cache_swap_low
3277 COMMENT: (percent, 0-100)
3280 LOC: Config.Swap.lowWaterMark
3283 NAME: cache_swap_high
3284 COMMENT: (percent, 0-100)
3287 LOC: Config.Swap.highWaterMark
3290 The low- and high-water marks for cache object replacement.
3291 Replacement begins when the swap (disk) usage is above the
3292 low-water mark and attempts to maintain utilization near the
3293 low-water mark. As swap utilization gets close to high-water
3294 mark object eviction becomes more aggressive. If utilization is
3295 close to the low-water mark less replacement is done each time.
3297 Defaults are 90% and 95%. If you have a large cache, 5% could be
3298 hundreds of MB. If this is the case you may wish to set these
3299 numbers closer together.
3304 -----------------------------------------------------------------------------
3314 logformat <name> <format specification>
3316 Defines an access log format.
3318 The <format specification> is a string with embedded % format codes
3320 % format codes all follow the same basic structure where all but
3321 the formatcode is optional. Output strings are automatically escaped
3322 as required according to their context and the output format
3323 modifiers are usually not needed, but can be specified if an explicit
3324 output format is desired.
3326 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3328 " output in quoted string format
3329 [ output in squid text log format as used by log_mime_hdrs
3330 # output in URL quoted format
3335 width minimum and/or maximum field width:
3336 [width_min][.width_max]
3337 When minimum starts with 0, the field is zero-padded.
3338 String values exceeding maximum width are truncated.
3340 {arg} argument such as header name etc
3344 % a literal % character
3345 sn Unique sequence number per log line entry
3346 err_code The ID of an error response served by Squid or
3347 a similar internal error identifier.
3348 err_detail Additional err_code-dependent error information.
3349 note The meta header specified by the argument. Also
3350 logs the adaptation meta headers set by the
3351 adaptation_meta configuration parameter.
3352 If no argument given all meta headers logged.
3354 Connection related format codes:
3356 >a Client source IP address
3358 >p Client source port
3359 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3360 >la Local IP address the client connected to
3361 >lp Local port number the client connected to
3363 la Local listening IP address the client connection was connected to.
3364 lp Local listening port number the client connection was connected to.
3366 <a Server IP address of the last server or peer connection
3367 <A Server FQDN or peer name
3368 <p Server port number of the last server or peer connection
3369 <la Local IP address of the last server or peer connection
3370 <lp Local port number of the last server or peer connection
3372 Time related format codes:
3374 ts Seconds since epoch
3375 tu subsecond time (milliseconds)
3376 tl Local time. Optional strftime format argument
3377 default %d/%b/%Y:%H:%M:%S %z
3378 tg GMT time. Optional strftime format argument
3379 default %d/%b/%Y:%H:%M:%S %z
3380 tr Response time (milliseconds)
3381 dt Total time spent making DNS lookups (milliseconds)
3383 Access Control related format codes:
3385 et Tag returned by external acl
3386 ea Log string returned by external acl
3387 un User name (any available)
3388 ul User name from authentication
3389 ue User name from external acl helper
3390 ui User name from ident
3391 us User name from SSL
3393 HTTP related format codes:
3395 [http::]>h Original request header. Optional header name argument
3396 on the format header[:[separator]element]
3397 [http::]>ha The HTTP request headers after adaptation and redirection.
3398 Optional header name argument as for >h
3399 [http::]<h Reply header. Optional header name argument
3401 [http::]>Hs HTTP status code sent to the client
3402 [http::]<Hs HTTP status code received from the next hop
3403 [http::]<bs Number of HTTP-equivalent message body bytes
3404 received from the next hop, excluding chunked
3405 transfer encoding and control messages.
3406 Generated FTP/Gopher listings are treated as
3408 [http::]mt MIME content type
3409 [http::]rm Request method (GET/POST etc)
3410 [http::]>rm Request method from client
3411 [http::]<rm Request method sent to server or peer
3412 [http::]ru Request URL from client (historic, filtered for logging)
3413 [http::]>ru Request URL from client
3414 [http::]<ru Request URL sent to server or peer
3415 [http::]rp Request URL-Path excluding hostname
3416 [http::]>rp Request URL-Path excluding hostname from client
3417 [http::]<rp Request URL-Path excluding hostname sento to server or peer
3418 [http::]rv Request protocol version
3419 [http::]>rv Request protocol version from client
3420 [http::]<rv Request protocol version sent to server or peer
3421 [http::]<st Sent reply size including HTTP headers
3422 [http::]>st Received request size including HTTP headers. In the
3423 case of chunked requests the chunked encoding metadata
3425 [http::]>sh Received HTTP request headers size
3426 [http::]<sh Sent HTTP reply headers size
3427 [http::]st Request+Reply size including HTTP headers
3428 [http::]<sH Reply high offset sent
3429 [http::]<sS Upstream object size
3430 [http::]<pt Peer response time in milliseconds. The timer starts
3431 when the last request byte is sent to the next hop
3432 and stops when the last response byte is received.
3433 [http::]<tt Total server-side time in milliseconds. The timer
3434 starts with the first connect request (or write I/O)
3435 sent to the first selected peer. The timer stops
3436 with the last I/O with the last peer.
3438 Squid handling related format codes:
3440 Ss Squid request status (TCP_MISS etc)
3441 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3443 SSL-related format codes:
3445 ssl::bump_mode SslBump decision for the transaction:
3447 For CONNECT requests that initiated bumping of
3448 a connection and for any request received on
3449 an already bumped connection, Squid logs the
3450 corresponding SslBump mode ("server-first" or
3451 "client-first"). See the ssl_bump option for
3452 more information about these modes.
3454 A "none" token is logged for requests that
3455 triggered "ssl_bump" ACL evaluation matching
3456 either a "none" rule or no rules at all.
3458 In all other cases, a single dash ("-") is
3461 If ICAP is enabled, the following code becomes available (as
3462 well as ICAP log codes documented with the icap_log option):
3464 icap::tt Total ICAP processing time for the HTTP
3465 transaction. The timer ticks when ICAP
3466 ACLs are checked and when ICAP
3467 transaction is in progress.
3469 If adaptation is enabled the following three codes become available:
3471 adapt::<last_h The header of the last ICAP response or
3472 meta-information from the last eCAP
3473 transaction related to the HTTP transaction.
3474 Like <h, accepts an optional header name
3477 adapt::sum_trs Summed adaptation transaction response
3478 times recorded as a comma-separated list in
3479 the order of transaction start time. Each time
3480 value is recorded as an integer number,
3481 representing response time of one or more
3482 adaptation (ICAP or eCAP) transaction in
3483 milliseconds. When a failed transaction is
3484 being retried or repeated, its time is not
3485 logged individually but added to the
3486 replacement (next) transaction. See also:
3489 adapt::all_trs All adaptation transaction response times.
3490 Same as adaptation_strs but response times of
3491 individual transactions are never added
3492 together. Instead, all transaction response
3493 times are recorded individually.
3495 You can prefix adapt::*_trs format codes with adaptation
3496 service name in curly braces to record response time(s) specific
3497 to that service. For example: %{my_service}adapt::sum_trs
3499 If SSL is enabled, the following formating codes become available:
3501 %ssl::>cert_subject The Subject field of the received client
3502 SSL certificate or a dash ('-') if Squid has
3503 received an invalid/malformed certificate or
3504 no certificate at all. Consider encoding the
3505 logged value because Subject often has spaces.
3507 %ssl::>cert_issuer The Issuer field of the received client
3508 SSL certificate or a dash ('-') if Squid has
3509 received an invalid/malformed certificate or
3510 no certificate at all. Consider encoding the
3511 logged value because Issuer often has spaces.
3513 The default formats available (which do not need re-defining) are:
3515 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3516 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3517 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3518 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3519 logformat useragent %>a [%tl] "%{User-Agent}>h"
3521 NOTE: When the log_mime_hdrs directive is set to ON.
3522 The squid, common and combined formats have a safely encoded copy
3523 of the mime headers appended to each line within a pair of brackets.
3525 NOTE: The common and combined formats are not quite true to the Apache definition.
3526 The logs from Squid contain an extra status and hierarchy code appended.
3530 NAME: access_log cache_access_log
3532 LOC: Config.Log.accesslogs
3533 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3535 These files log client request activities. Has a line every HTTP or
3536 ICP request. The format is:
3537 access_log <module>:<place> [<logformat name> [acl acl ...]]
3538 access_log none [acl acl ...]]
3540 Will log to the specified module:place using the specified format (which
3541 must be defined in a logformat directive) those entries which match
3542 ALL the acl's specified (which must be defined in acl clauses).
3543 If no acl is specified, all requests will be logged to this destination.
3545 ===== Modules Currently available =====
3547 none Do not log any requests matching these ACL.
3548 Do not specify Place or logformat name.
3550 stdio Write each log line to disk immediately at the completion of
3552 Place: the filename and path to be written.
3554 daemon Very similar to stdio. But instead of writing to disk the log
3555 line is passed to a daemon helper for asychronous handling instead.
3556 Place: varies depending on the daemon.
3558 log_file_daemon Place: the file name and path to be written.
3560 syslog To log each request via syslog facility.
3561 Place: The syslog facility and priority level for these entries.
3562 Place Format: facility.priority
3564 where facility could be any of:
3565 authpriv, daemon, local0 ... local7 or user.
3567 And priority could be any of:
3568 err, warning, notice, info, debug.
3570 udp To send each log line as text data to a UDP receiver.
3571 Place: The destination host name or IP and port.
3572 Place Format: //host:port
3574 tcp To send each log line as text data to a TCP receiver.
3575 Place: The destination host name or IP and port.
3576 Place Format: //host:port
3579 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3585 LOC: Config.Log.icaplogs
3588 ICAP log files record ICAP transaction summaries, one line per
3591 The icap_log option format is:
3592 icap_log <filepath> [<logformat name> [acl acl ...]]
3593 icap_log none [acl acl ...]]
3595 Please see access_log option documentation for details. The two
3596 kinds of logs share the overall configuration approach and many
3599 ICAP processing of a single HTTP message or transaction may
3600 require multiple ICAP transactions. In such cases, multiple
3601 ICAP transaction log lines will correspond to a single access
3604 ICAP log uses logformat codes that make sense for an ICAP
3605 transaction. Header-related codes are applied to the HTTP header
3606 embedded in an ICAP server response, with the following caveats:
3607 For REQMOD, there is no HTTP response header unless the ICAP
3608 server performed request satisfaction. For RESPMOD, the HTTP
3609 request header is the header sent to the ICAP server. For
3610 OPTIONS, there are no HTTP headers.
3612 The following format codes are also available for ICAP logs:
3614 icap::<A ICAP server IP address. Similar to <A.
3616 icap::<service_name ICAP service name from the icap_service
3617 option in Squid configuration file.
3619 icap::ru ICAP Request-URI. Similar to ru.
3621 icap::rm ICAP request method (REQMOD, RESPMOD, or
3622 OPTIONS). Similar to existing rm.
3624 icap::>st Bytes sent to the ICAP server (TCP payload
3625 only; i.e., what Squid writes to the socket).
3627 icap::<st Bytes received from the ICAP server (TCP
3628 payload only; i.e., what Squid reads from
3631 icap::<bs Number of message body bytes received from the
3632 ICAP server. ICAP message body, if any, usually
3633 includes encapsulated HTTP message headers and
3634 possibly encapsulated HTTP message body. The
3635 HTTP body part is dechunked before its size is
3638 icap::tr Transaction response time (in
3639 milliseconds). The timer starts when
3640 the ICAP transaction is created and
3641 stops when the transaction is completed.
3644 icap::tio Transaction I/O time (in milliseconds). The
3645 timer starts when the first ICAP request
3646 byte is scheduled for sending. The timers
3647 stops when the last byte of the ICAP response
3650 icap::to Transaction outcome: ICAP_ERR* for all
3651 transaction errors, ICAP_OPT for OPTION
3652 transactions, ICAP_ECHO for 204
3653 responses, ICAP_MOD for message
3654 modification, and ICAP_SAT for request
3655 satisfaction. Similar to Ss.
3657 icap::Hs ICAP response status code. Similar to Hs.
3659 icap::>h ICAP request header(s). Similar to >h.
3661 icap::<h ICAP response header(s). Similar to <h.
3663 The default ICAP log format, which can be used without an explicit
3664 definition, is called icap_squid:
3666 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3668 See also: logformat, log_icap, and %adapt::<last_h
3671 NAME: logfile_daemon
3673 DEFAULT: @DEFAULT_LOGFILED@
3674 LOC: Log::TheConfig.logfile_daemon
3676 Specify the path to the logfile-writing daemon. This daemon is
3677 used to write the access and store logs, if configured.
3679 Squid sends a number of commands to the log daemon:
3680 L<data>\n - logfile data
3685 r<n>\n - set rotate count to <n>
3686 b<n>\n - 1 = buffer output, 0 = don't buffer output
3688 No responses is expected.
3693 LOC: Config.accessList.log
3695 COMMENT: allow|deny acl acl...
3697 This options allows you to control which requests gets logged
3698 to access.log (see access_log directive). Requests denied for
3699 logging will also not be accounted for in performance counters.
3701 This clause only supports fast acl types.
3702 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3708 LOC: Config.accessList.icap
3711 This options allows you to control which requests get logged
3712 to icap.log. See the icap_log directive for ICAP log details.
3715 NAME: cache_store_log
3718 LOC: Config.Log.store
3720 Logs the activities of the storage manager. Shows which
3721 objects are ejected from the cache, and which objects are
3722 saved and for how long.
3723 There are not really utilities to analyze this data, so you can safely
3724 disable it (the default).
3726 Store log uses modular logging outputs. See access_log for the list
3727 of modules supported.
3730 cache_store_log stdio:@DEFAULT_STORE_LOG@
3731 cache_store_log daemon:@DEFAULT_STORE_LOG@
3734 NAME: cache_swap_state cache_swap_log
3736 LOC: Config.Log.swap
3739 Location for the cache "swap.state" file. This index file holds
3740 the metadata of objects saved on disk. It is used to rebuild
3741 the cache during startup. Normally this file resides in each
3742 'cache_dir' directory, but you may specify an alternate
3743 pathname here. Note you must give a full filename, not just
3744 a directory. Since this is the index for the whole object
3745 list you CANNOT periodically rotate it!
3747 If %s can be used in the file name it will be replaced with a
3748 a representation of the cache_dir name where each / is replaced
3749 with '.'. This is needed to allow adding/removing cache_dir
3750 lines when cache_swap_log is being used.
3752 If have more than one 'cache_dir', and %s is not used in the name
3753 these swap logs will have names such as:
3759 The numbered extension (which is added automatically)
3760 corresponds to the order of the 'cache_dir' lines in this
3761 configuration file. If you change the order of the 'cache_dir'
3762 lines in this file, these index files will NOT correspond to
3763 the correct 'cache_dir' entry (unless you manually rename
3764 them). We recommend you do NOT use this option. It is
3765 better to keep these index files in each 'cache_dir' directory.
3768 NAME: logfile_rotate
3771 LOC: Config.Log.rotateNumber
3773 Specifies the number of logfile rotations to make when you
3774 type 'squid -k rotate'. The default is 10, which will rotate
3775 with extensions 0 through 9. Setting logfile_rotate to 0 will
3776 disable the file name rotation, but the logfiles are still closed
3777 and re-opened. This will enable you to rename the logfiles
3778 yourself just before sending the rotate signal.
3780 Note, the 'squid -k rotate' command normally sends a USR1
3781 signal to the running squid process. In certain situations
3782 (e.g. on Linux with Async I/O), USR1 is used for other
3783 purposes, so -k rotate uses another signal. It is best to get
3784 in the habit of using 'squid -k rotate' instead of 'kill -USR1
3787 Note, from Squid-3.1 this option has no effect on the cache.log,
3788 that log can be rotated separately by using debug_options
3791 NAME: emulate_httpd_log
3794 Replace this with an access_log directive using the format 'common' or 'combined'.
3797 NAME: log_ip_on_direct
3800 Remove this option from your config. To log server or peer names use %<A in the log format.
3805 DEFAULT: @DEFAULT_MIME_TABLE@
3806 LOC: Config.mimeTablePathname
3808 Pathname to Squid's MIME table. You shouldn't need to change
3809 this, but the default file contains examples and formatting
3810 information if you do.
3816 LOC: Config.onoff.log_mime_hdrs
3819 The Cache can record both the request and the response MIME
3820 headers for each HTTP transaction. The headers are encoded
3821 safely and will appear as two bracketed fields at the end of
3822 the access log (for either the native or httpd-emulated log
3823 formats). To enable this logging set log_mime_hdrs to 'on'.
3829 Replace this with an access_log directive using the format 'useragent'.
3832 NAME: referer_log referrer_log
3835 Replace this with an access_log directive using the format 'referrer'.
3840 DEFAULT: @DEFAULT_PID_FILE@
3841 LOC: Config.pidFilename
3843 A filename to write the process-id to. To disable, enter "none".
3849 Remove this option from your config. To log FQDN use %>A in the log format.
3852 NAME: client_netmask
3854 LOC: Config.Addrs.client_netmask
3857 A netmask for client addresses in logfiles and cachemgr output.
3858 Change this to protect the privacy of your cache clients.
3859 A netmask of 255.255.255.0 will log all IP's in that range with
3860 the last digit set to '0'.
3866 Use a regular access.log with ACL limiting it to MISS events.
3869 NAME: strip_query_terms
3871 LOC: Config.onoff.strip_query_terms
3874 By default, Squid strips query terms from requested URLs before
3875 logging. This protects your user's privacy.
3882 LOC: Config.onoff.buffered_logs
3884 cache.log log file is written with stdio functions, and as such
3885 it can be buffered or unbuffered. By default it will be unbuffered.
3886 Buffering it can speed up the writing slightly (though you are
3887 unlikely to need to worry unless you run with tons of debugging
3888 enabled in which case performance will suffer badly anyway..).
3891 NAME: netdb_filename
3893 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
3894 LOC: Config.netdbFilename
3897 A filename where Squid stores it's netdb state between restarts.
3898 To disable, enter "none".
3902 OPTIONS FOR TROUBLESHOOTING
3903 -----------------------------------------------------------------------------
3908 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
3909 LOC: Debug::cache_log
3911 Cache logging file. This is where general information about
3912 your cache's behavior goes. You can increase the amount of data
3913 logged to this file and how often its rotated with "debug_options"
3919 LOC: Debug::debugOptions
3921 Logging options are set as section,level where each source file
3922 is assigned a unique section. Lower levels result in less
3923 output, Full debugging (level 9) can result in a very large
3924 log file, so be careful.
3926 The magic word "ALL" sets debugging levels for all sections.
3927 We recommend normally running with "ALL,1".
3929 The rotate=N option can be used to keep more or less of these logs
3930 than would otherwise be kept by logfile_rotate.
3931 For most uses a single log should be enough to monitor current
3932 events affecting Squid.
3937 LOC: Config.coredump_dir
3938 DEFAULT_IF_NONE: none
3940 By default Squid leaves core files in the directory from where
3941 it was started. If you set 'coredump_dir' to a directory
3942 that exists, Squid will chdir() to that directory at startup
3943 and coredump files will be left there.
3947 # Leave coredumps in the first cache dir
3948 coredump_dir @DEFAULT_SWAP_DIR@
3954 OPTIONS FOR FTP GATEWAYING
3955 -----------------------------------------------------------------------------
3961 LOC: Config.Ftp.anon_user
3963 If you want the anonymous login password to be more informative
3964 (and enable the use of picky ftp servers), set this to something
3965 reasonable for your domain, like wwwuser@somewhere.net
3967 The reason why this is domainless by default is the
3968 request can be made on the behalf of a user in any domain,
3969 depending on how the cache is used.
3970 Some ftp server also validate the email address is valid
3971 (for example perl.com).
3977 LOC: Config.Ftp.passive
3979 If your firewall does not allow Squid to use passive
3980 connections, turn off this option.
3982 Use of ftp_epsv_all option requires this to be ON.
3988 LOC: Config.Ftp.epsv_all
3990 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
3992 NATs may be able to put the connection on a "fast path" through the
3993 translator, as the EPRT command will never be used and therefore,
3994 translation of the data portion of the segments will never be needed.
3996 When a client only expects to do two-way FTP transfers this may be
3998 If squid finds that it must do a three-way FTP transfer after issuing
3999 an EPSV ALL command, the FTP session will fail.
4001 If you have any doubts about this option do not use it.
4002 Squid will nicely attempt all other connection methods.
4004 Requires ftp_passive to be ON (default) for any effect.
4010 LOC: Config.Ftp.epsv
4012 FTP Protocol extensions permit the use of a special "EPSV" command.
4014 NATs may be able to put the connection on a "fast path" through the
4015 translator using EPSV, as the EPRT command will never be used
4016 and therefore, translation of the data portion of the segments
4017 will never be needed.
4019 Turning this OFF will prevent EPSV being attempted.
4020 WARNING: Doing so will convert Squid back to the old behavior with all
4021 the related problems with external NAT devices/layers.
4023 Requires ftp_passive to be ON (default) for any effect.
4029 LOC: Config.Ftp.eprt
4031 FTP Protocol extensions permit the use of a special "EPRT" command.
4033 This extension provides a protocol neutral alternative to the
4034 IPv4-only PORT command. When supported it enables active FTP data
4035 channels over IPv6 and efficient NAT handling.
4037 Turning this OFF will prevent EPRT being attempted and will skip
4038 straight to using PORT for IPv4 servers.
4040 Some devices are known to not handle this extension correctly and
4041 may result in crashes. Devices which suport EPRT enough to fail
4042 cleanly will result in Squid attempting PORT anyway. This directive
4043 should only be disabled when EPRT results in device failures.
4045 WARNING: Doing so will convert Squid back to the old behavior with all
4046 the related problems with external NAT devices/layers and IPv4-only FTP.
4049 NAME: ftp_sanitycheck
4052 LOC: Config.Ftp.sanitycheck
4054 For security and data integrity reasons Squid by default performs
4055 sanity checks of the addresses of FTP data connections ensure the
4056 data connection is to the requested server. If you need to allow
4057 FTP connections to servers using another IP address for the data
4058 connection turn this off.
4061 NAME: ftp_telnet_protocol
4064 LOC: Config.Ftp.telnet
4066 The FTP protocol is officially defined to use the telnet protocol
4067 as transport channel for the control connection. However, many
4068 implementations are broken and does not respect this aspect of
4071 If you have trouble accessing files with ASCII code 255 in the
4072 path or similar problems involving this ASCII code you can
4073 try setting this directive to off. If that helps, report to the
4074 operator of the FTP server in question that their FTP server
4075 is broken and does not follow the FTP standard.
4079 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4080 -----------------------------------------------------------------------------
4085 DEFAULT: @DEFAULT_DISKD@
4086 LOC: Config.Program.diskd
4088 Specify the location of the diskd executable.
4089 Note this is only useful if you have compiled in
4090 diskd as one of the store io modules.
4093 NAME: unlinkd_program
4096 DEFAULT: @DEFAULT_UNLINKD@
4097 LOC: Config.Program.unlinkd
4099 Specify the location of the executable for file deletion process.
4102 NAME: pinger_program
4104 DEFAULT: @DEFAULT_PINGER@
4105 LOC: Config.pinger.program
4108 Specify the location of the executable for the pinger process.
4114 LOC: Config.pinger.enable
4117 Control whether the pinger is active at run-time.
4118 Enables turning ICMP pinger on and off with a simple
4119 squid -k reconfigure.
4124 OPTIONS FOR URL REWRITING
4125 -----------------------------------------------------------------------------
4128 NAME: url_rewrite_program redirect_program
4130 LOC: Config.Program.redirect
4133 Specify the location of the executable URL rewriter to use.
4134 Since they can perform almost any function there isn't one included.
4136 For each requested URL, the rewriter will receive on line with the format
4138 [channel-ID <SP>] URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kv-pairs]<NL>
4141 After processing the request the helper must reply using the following format:
4143 [channel-ID <SP>] result [<SP> kv-pairs]
4145 The result code can be:
4147 OK status=30N url="..."
4148 Redirect the URL to the one supplied in 'url='.
4149 'status=' is optional and contains the status code to send
4150 the client in Squids HTTP response. It must be one of the
4151 HTTP redirect status codes: 301, 302, 303, 307, 308.
4152 When no status is given Squid will use 302.
4154 OK rewrite-url="..."
4155 Rewrite the URL to the one supplied in 'rewrite-url='.
4156 The new URL is fetched directly by Squid and returned to
4157 the client as the response to its request.
4160 Do not change the URL.
4163 An internal error occured in the helper, preventing
4164 a result being identified.
4167 In the future, the interface protocol will be extended with
4168 key=value pairs ("kv-pairs" shown above). Helper programs
4169 should be prepared to receive and possibly ignore additional
4170 whitespace-separated tokens on each input line.
4172 When using the concurrency= option the protocol is changed by
4173 introducing a query channel tag in front of the request/response.
4174 The query channel tag is a number between 0 and concurrency-1.
4175 This value must be echoed back unchanged to Squid as the first part
4176 of the response relating to its request.
4178 WARNING: URL re-writing ability should be avoided whenever possible.
4179 Use the URL redirect form of response instead.
4181 Re-write creates a difference in the state held by the client
4182 and server. Possibly causing confusion when the server response
4183 contains snippets of its view state. Embeded URLs, response
4184 and content Location headers, etc. are not re-written by this
4187 By default, a URL rewriter is not used.
4190 NAME: url_rewrite_children redirect_children
4191 TYPE: HelperChildConfig
4192 DEFAULT: 20 startup=0 idle=1 concurrency=0
4193 LOC: Config.redirectChildren
4195 The maximum number of redirector processes to spawn. If you limit
4196 it too few Squid will have to wait for them to process a backlog of
4197 URLs, slowing it down. If you allow too many they will use RAM
4198 and other system resources noticably.
4200 The startup= and idle= options allow some measure of skew in your
4205 Sets a minimum of how many processes are to be spawned when Squid
4206 starts or reconfigures. When set to zero the first request will
4207 cause spawning of the first child process to handle it.
4209 Starting too few will cause an initial slowdown in traffic as Squid
4210 attempts to simultaneously spawn enough processes to cope.
4214 Sets a minimum of how many processes Squid is to try and keep available
4215 at all times. When traffic begins to rise above what the existing
4216 processes can handle this many more will be spawned up to the maximum
4217 configured. A minimum setting of 1 is required.
4221 The number of requests each redirector helper can handle in
4222 parallel. Defaults to 0 which indicates the redirector
4223 is a old-style single threaded redirector.
4225 When this directive is set to a value >= 1 then the protocol
4226 used to communicate with the helper is modified to include
4227 a request ID in front of the request/response. The request
4228 ID from the request must be echoed back with the response
4232 NAME: url_rewrite_host_header redirect_rewrites_host_header
4235 LOC: Config.onoff.redir_rewrites_host
4237 To preserve same-origin security policies in browsers and
4238 prevent Host: header forgery by redirectors Squid rewrites
4239 any Host: header in redirected requests.
4241 If you are running an accelerator this may not be a wanted
4242 effect of a redirector. This directive enables you disable
4243 Host: alteration in reverse-proxy traffic.
4245 WARNING: Entries are cached on the result of the URL rewriting
4246 process, so be careful if you have domain-virtual hosts.
4248 WARNING: Squid and other software verifies the URL and Host
4249 are matching, so be careful not to relay through other proxies
4250 or inspecting firewalls with this disabled.
4253 NAME: url_rewrite_access redirector_access
4256 LOC: Config.accessList.redirector
4258 If defined, this access list specifies which requests are
4259 sent to the redirector processes. By default all requests
4262 This clause supports both fast and slow acl types.
4263 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4266 NAME: url_rewrite_bypass redirector_bypass
4268 LOC: Config.onoff.redirector_bypass
4271 When this is 'on', a request will not go through the
4272 redirector if all redirectors are busy. If this is 'off'
4273 and the redirector queue grows too large, Squid will exit
4274 with a FATAL error and ask you to increase the number of
4275 redirectors. You should only enable this if the redirectors
4276 are not critical to your caching system. If you use
4277 redirectors for access control, and you enable this option,
4278 users may have access to pages they should not
4279 be allowed to request.
4283 OPTIONS FOR TUNING THE CACHE
4284 -----------------------------------------------------------------------------
4287 NAME: cache no_cache
4290 LOC: Config.accessList.noCache
4292 A list of ACL elements which, if matched and denied, cause the request to
4293 not be satisfied from the cache and the reply to not be cached.
4294 In other words, use this to force certain objects to never be cached.
4296 You must use the words 'allow' or 'deny' to indicate whether items
4297 matching the ACL should be allowed or denied into the cache.
4299 Default is to allow all to be cached.
4301 This clause supports both fast and slow acl types.
4302 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4308 LOC: Config.maxStale
4311 This option puts an upper limit on how stale content Squid
4312 will serve from the cache if cache validation fails.
4313 Can be overriden by the refresh_pattern max-stale option.
4316 NAME: refresh_pattern
4317 TYPE: refreshpattern
4321 usage: refresh_pattern [-i] regex min percent max [options]
4323 By default, regular expressions are CASE-SENSITIVE. To make
4324 them case-insensitive, use the -i option.
4326 'Min' is the time (in minutes) an object without an explicit
4327 expiry time should be considered fresh. The recommended
4328 value is 0, any higher values may cause dynamic applications
4329 to be erroneously cached unless the application designer
4330 has taken the appropriate actions.
4332 'Percent' is a percentage of the objects age (time since last
4333 modification age) an object without explicit expiry time
4334 will be considered fresh.
4336 'Max' is an upper limit on how long objects without an explicit
4337 expiry time will be considered fresh.
4339 options: override-expire
4344 ignore-must-revalidate
4351 override-expire enforces min age even if the server
4352 sent an explicit expiry time (e.g., with the
4353 Expires: header or Cache-Control: max-age). Doing this
4354 VIOLATES the HTTP standard. Enabling this feature
4355 could make you liable for problems which it causes.
4357 Note: override-expire does not enforce staleness - it only extends
4358 freshness / min. If the server returns a Expires time which
4359 is longer than your max time, Squid will still consider
4360 the object fresh for that period of time.
4362 override-lastmod enforces min age even on objects
4363 that were modified recently.
4365 reload-into-ims changes client no-cache or ``reload''
4366 to If-Modified-Since requests. Doing this VIOLATES the
4367 HTTP standard. Enabling this feature could make you
4368 liable for problems which it causes.
4370 ignore-reload ignores a client no-cache or ``reload''
4371 header. Doing this VIOLATES the HTTP standard. Enabling
4372 this feature could make you liable for problems which
4375 ignore-no-store ignores any ``Cache-control: no-store''
4376 headers received from a server. Doing this VIOLATES
4377 the HTTP standard. Enabling this feature could make you
4378 liable for problems which it causes.
4380 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
4381 headers received from a server. Doing this VIOLATES
4382 the HTTP standard. Enabling this feature could make you
4383 liable for problems which it causes.
4385 ignore-private ignores any ``Cache-control: private''
4386 headers received from a server. Doing this VIOLATES
4387 the HTTP standard. Enabling this feature could make you
4388 liable for problems which it causes.
4390 ignore-auth caches responses to requests with authorization,
4391 as if the originserver had sent ``Cache-control: public''
4392 in the response header. Doing this VIOLATES the HTTP standard.
4393 Enabling this feature could make you liable for problems which
4396 refresh-ims causes squid to contact the origin server
4397 when a client issues an If-Modified-Since request. This
4398 ensures that the client will receive an updated version
4399 if one is available.
4401 store-stale stores responses even if they don't have explicit
4402 freshness or a validator (i.e., Last-Modified or an ETag)
4403 present, or if they're already stale. By default, Squid will
4404 not cache such responses because they usually can't be
4405 reused. Note that such responses will be stale by default.
4407 max-stale=NN provide a maximum staleness factor. Squid won't
4408 serve objects more stale than this even if it failed to
4409 validate the object. Default: use the max_stale global limit.
4411 Basically a cached object is:
4413 FRESH if expires < now, else STALE
4415 FRESH if lm-factor < percent, else STALE
4419 The refresh_pattern lines are checked in the order listed here.
4420 The first entry which matches is used. If none of the entries
4421 match the default will be used.
4423 Note, you must uncomment all the default lines if you want
4424 to change one. The default setting is only active if none is
4429 # Add any of your own refresh_pattern entries above these.
4430 refresh_pattern ^ftp: 1440 20% 10080
4431 refresh_pattern ^gopher: 1440 0% 1440
4432 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
4433 refresh_pattern . 0 20% 4320
4437 NAME: quick_abort_min
4441 LOC: Config.quickAbort.min
4444 NAME: quick_abort_max
4448 LOC: Config.quickAbort.max
4451 NAME: quick_abort_pct
4455 LOC: Config.quickAbort.pct
4457 The cache by default continues downloading aborted requests
4458 which are almost completed (less than 16 KB remaining). This
4459 may be undesirable on slow (e.g. SLIP) links and/or very busy
4460 caches. Impatient users may tie up file descriptors and
4461 bandwidth by repeatedly requesting and immediately aborting
4464 When the user aborts a request, Squid will check the
4465 quick_abort values to the amount of data transfered until
4468 If the transfer has less than 'quick_abort_min' KB remaining,
4469 it will finish the retrieval.
4471 If the transfer has more than 'quick_abort_max' KB remaining,
4472 it will abort the retrieval.
4474 If more than 'quick_abort_pct' of the transfer has completed,
4475 it will finish the retrieval.
4477 If you do not want any retrieval to continue after the client
4478 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
4481 If you want retrievals to always continue if they are being
4482 cached set 'quick_abort_min' to '-1 KB'.
4485 NAME: read_ahead_gap
4486 COMMENT: buffer-size
4488 LOC: Config.readAheadGap
4491 The amount of data the cache will buffer ahead of what has been
4492 sent to the client when retrieving an object from another server.
4496 IFDEF: USE_HTTP_VIOLATIONS
4499 LOC: Config.negativeTtl
4502 Set the Default Time-to-Live (TTL) for failed requests.
4503 Certain types of failures (such as "connection refused" and
4504 "404 Not Found") are able to be negatively-cached for a short time.
4505 Modern web servers should provide Expires: header, however if they
4506 do not this can provide a minimum TTL.
4507 The default is not to cache errors with unknown expiry details.
4509 Note that this is different from negative caching of DNS lookups.
4511 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4512 this feature could make you liable for problems which it
4516 NAME: positive_dns_ttl
4519 LOC: Config.positiveDnsTtl
4522 Upper limit on how long Squid will cache positive DNS responses.
4523 Default is 6 hours (360 minutes). This directive must be set
4524 larger than negative_dns_ttl.
4527 NAME: negative_dns_ttl
4530 LOC: Config.negativeDnsTtl
4533 Time-to-Live (TTL) for negative caching of failed DNS lookups.
4534 This also sets the lower cache limit on positive lookups.
4535 Minimum value is 1 second, and it is not recommendable to go
4536 much below 10 seconds.
4539 NAME: range_offset_limit
4540 COMMENT: size [acl acl...]
4542 LOC: Config.rangeOffsetLimit
4545 usage: (size) [units] [[!]aclname]
4547 Sets an upper limit on how far (number of bytes) into the file
4548 a Range request may be to cause Squid to prefetch the whole file.
4549 If beyond this limit, Squid forwards the Range request as it is and
4550 the result is NOT cached.
4552 This is to stop a far ahead range request (lets say start at 17MB)
4553 from making Squid fetch the whole object up to that point before
4554 sending anything to the client.
4556 Multiple range_offset_limit lines may be specified, and they will
4557 be searched from top to bottom on each request until a match is found.
4558 The first match found will be used. If no line matches a request, the
4559 default limit of 0 bytes will be used.
4561 'size' is the limit specified as a number of units.
4563 'units' specifies whether to use bytes, KB, MB, etc.
4564 If no units are specified bytes are assumed.
4566 A size of 0 causes Squid to never fetch more than the
4567 client requested. (default)
4569 A size of 'none' causes Squid to always fetch the object from the
4570 beginning so it may cache the result. (2.0 style)
4572 'aclname' is the name of a defined ACL.
4574 NP: Using 'none' as the byte value here will override any quick_abort settings
4575 that may otherwise apply to the range request. The range request will
4576 be fully fetched from start to finish regardless of the client
4577 actions. This affects bandwidth usage.
4580 NAME: minimum_expiry_time
4583 LOC: Config.minimum_expiry_time
4586 The minimum caching time according to (Expires - Date)
4587 Headers Squid honors if the object can't be revalidated
4588 defaults to 60 seconds. In reverse proxy environments it
4589 might be desirable to honor shorter object lifetimes. It
4590 is most likely better to make your server return a
4591 meaningful Last-Modified header however. In ESI environments
4592 where page fragments often have short lifetimes, this will
4593 often be best set to 0.
4596 NAME: store_avg_object_size
4600 LOC: Config.Store.avgObjectSize
4602 Average object size, used to estimate number of objects your
4603 cache can hold. The default is 13 KB.
4606 NAME: store_objects_per_bucket
4609 LOC: Config.Store.objectsPerBucket
4611 Target number of objects per bucket in the store hash table.
4612 Lowering this value increases the total number of buckets and
4613 also the storage maintenance rate. The default is 20.
4618 -----------------------------------------------------------------------------
4621 NAME: request_header_max_size
4625 LOC: Config.maxRequestHeaderSize
4627 This specifies the maximum size for HTTP headers in a request.
4628 Request headers are usually relatively small (about 512 bytes).
4629 Placing a limit on the request header size will catch certain
4630 bugs (for example with persistent connections) and possibly
4631 buffer-overflow or denial-of-service attacks.
4634 NAME: reply_header_max_size
4638 LOC: Config.maxReplyHeaderSize
4640 This specifies the maximum size for HTTP headers in a reply.
4641 Reply headers are usually relatively small (about 512 bytes).
4642 Placing a limit on the reply header size will catch certain
4643 bugs (for example with persistent connections) and possibly
4644 buffer-overflow or denial-of-service attacks.
4647 NAME: request_body_max_size
4651 LOC: Config.maxRequestBodySize
4653 This specifies the maximum size for an HTTP request body.
4654 In other words, the maximum size of a PUT/POST request.
4655 A user who attempts to send a request with a body larger
4656 than this limit receives an "Invalid Request" error message.
4657 If you set this parameter to a zero (the default), there will
4658 be no limit imposed.
4661 NAME: client_request_buffer_max_size
4665 LOC: Config.maxRequestBufferSize
4667 This specifies the maximum buffer size of a client request.
4668 It prevents squid eating too much memory when somebody uploads
4672 NAME: chunked_request_body_max_size
4676 LOC: Config.maxChunkedRequestBodySize
4678 A broken or confused HTTP/1.1 client may send a chunked HTTP
4679 request to Squid. Squid does not have full support for that
4680 feature yet. To cope with such requests, Squid buffers the
4681 entire request and then dechunks request body to create a
4682 plain HTTP/1.0 request with a known content length. The plain
4683 request is then used by the rest of Squid code as usual.
4685 The option value specifies the maximum size of the buffer used
4686 to hold the request before the conversion. If the chunked
4687 request size exceeds the specified limit, the conversion
4688 fails, and the client receives an "unsupported request" error,
4689 as if dechunking was disabled.
4691 Dechunking is enabled by default. To disable conversion of
4692 chunked requests, set the maximum to zero.
4694 Request dechunking feature and this option in particular are a
4695 temporary hack. When chunking requests and responses are fully
4696 supported, there will be no need to buffer a chunked request.
4700 IFDEF: USE_HTTP_VIOLATIONS
4703 LOC: Config.accessList.brokenPosts
4705 A list of ACL elements which, if matched, causes Squid to send
4706 an extra CRLF pair after the body of a PUT/POST request.
4708 Some HTTP servers has broken implementations of PUT/POST,
4709 and rely on an extra CRLF pair sent by some WWW clients.
4711 Quote from RFC2616 section 4.1 on this matter:
4713 Note: certain buggy HTTP/1.0 client implementations generate an
4714 extra CRLF's after a POST request. To restate what is explicitly
4715 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
4716 a request with an extra CRLF.
4718 This clause only supports fast acl types.
4719 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4722 acl buggy_server url_regex ^http://....
4723 broken_posts allow buggy_server
4726 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
4729 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
4731 LOC: Adaptation::Config::use_indirect_client
4733 Controls whether the indirect client IP address (instead of the direct
4734 client IP address) is passed to adaptation services.
4736 See also: follow_x_forwarded_for adaptation_send_client_ip
4740 IFDEF: USE_HTTP_VIOLATIONS
4744 LOC: Config.onoff.via
4746 If set (default), Squid will include a Via header in requests and
4747 replies as required by RFC2616.
4753 LOC: Config.onoff.ie_refresh
4756 Microsoft Internet Explorer up until version 5.5 Service
4757 Pack 1 has an issue with transparent proxies, wherein it
4758 is impossible to force a refresh. Turning this on provides
4759 a partial fix to the problem, by causing all IMS-REFRESH
4760 requests from older IE versions to check the origin server
4761 for fresh content. This reduces hit ratio by some amount
4762 (~10% in my experience), but allows users to actually get
4763 fresh content when they want it. Note because Squid
4764 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
4765 of 5.5 is unchanged from old versions of Squid (i.e. a
4766 forced refresh is impossible). Newer versions of IE will,
4767 hopefully, continue to have the new behavior and will be
4768 handled based on that assumption. This option defaults to
4769 the old Squid behavior, which is better for hit ratios but
4770 worse for clients using IE, if they need to be able to
4771 force fresh content.
4774 NAME: vary_ignore_expire
4777 LOC: Config.onoff.vary_ignore_expire
4780 Many HTTP servers supporting Vary gives such objects
4781 immediate expiry time with no cache-control header
4782 when requested by a HTTP/1.0 client. This option
4783 enables Squid to ignore such expiry times until
4784 HTTP/1.1 is fully implemented.
4786 WARNING: If turned on this may eventually cause some
4787 varying objects not intended for caching to get cached.
4790 NAME: request_entities
4792 LOC: Config.onoff.request_entities
4795 Squid defaults to deny GET and HEAD requests with request entities,
4796 as the meaning of such requests are undefined in the HTTP standard
4797 even if not explicitly forbidden.
4799 Set this directive to on if you have clients which insists
4800 on sending request entities in GET or HEAD requests. But be warned
4801 that there is server software (both proxies and web servers) which
4802 can fail to properly process this kind of request which may make you
4803 vulnerable to cache pollution attacks if enabled.
4806 NAME: request_header_access
4807 IFDEF: USE_HTTP_VIOLATIONS
4808 TYPE: http_header_access
4809 LOC: Config.request_header_access
4812 Usage: request_header_access header_name allow|deny [!]aclname ...
4814 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4815 this feature could make you liable for problems which it
4818 This option replaces the old 'anonymize_headers' and the
4819 older 'http_anonymizer' option with something that is much
4820 more configurable. A list of ACLs for each header name allows
4821 removal of specific header fields under specific conditions.
4823 This option only applies to outgoing HTTP request headers (i.e.,
4824 headers sent by Squid to the next HTTP hop such as a cache peer
4825 or an origin server). The option has no effect during cache hit
4826 detection. The equivalent adaptation vectoring point in ICAP
4827 terminology is post-cache REQMOD.
4829 The option is applied to individual outgoing request header
4830 fields. For each request header field F, Squid uses the first
4831 qualifying sets of request_header_access rules:
4833 1. Rules with header_name equal to F's name.
4834 2. Rules with header_name 'Other', provided F's name is not
4835 on the hard-coded list of commonly used HTTP header names.
4836 3. Rules with header_name 'All'.
4838 Within that qualifying rule set, rule ACLs are checked as usual.
4839 If ACLs of an "allow" rule match, the header field is allowed to
4840 go through as is. If ACLs of a "deny" rule match, the header is
4841 removed and request_header_replace is then checked to identify
4842 if the removed header has a replacement. If no rules within the
4843 set have matching ACLs, the header field is left as is.
4845 For example, to achieve the same behavior as the old
4846 'http_anonymizer standard' option, you should use:
4848 request_header_access From deny all
4849 request_header_access Referer deny all
4850 request_header_access Server deny all
4851 request_header_access User-Agent deny all
4852 request_header_access WWW-Authenticate deny all
4853 request_header_access Link deny all
4855 Or, to reproduce the old 'http_anonymizer paranoid' feature
4858 request_header_access Allow allow all
4859 request_header_access Authorization allow all
4860 request_header_access WWW-Authenticate allow all
4861 request_header_access Proxy-Authorization allow all
4862 request_header_access Proxy-Authenticate allow all
4863 request_header_access Cache-Control allow all
4864 request_header_access Content-Encoding allow all
4865 request_header_access Content-Length allow all
4866 request_header_access Content-Type allow all
4867 request_header_access Date allow all
4868 request_header_access Expires allow all
4869 request_header_access Host allow all
4870 request_header_access If-Modified-Since allow all
4871 request_header_access Last-Modified allow all
4872 request_header_access Location allow all
4873 request_header_access Pragma allow all
4874 request_header_access Accept allow all
4875 request_header_access Accept-Charset allow all
4876 request_header_access Accept-Encoding allow all
4877 request_header_access Accept-Language allow all
4878 request_header_access Content-Language allow all
4879 request_header_access Mime-Version allow all
4880 request_header_access Retry-After allow all
4881 request_header_access Title allow all
4882 request_header_access Connection allow all
4883 request_header_access All deny all
4885 although many of those are HTTP reply headers, and so should be
4886 controlled with the reply_header_access directive.
4888 By default, all headers are allowed (no anonymizing is
4892 NAME: reply_header_access
4893 IFDEF: USE_HTTP_VIOLATIONS
4894 TYPE: http_header_access
4895 LOC: Config.reply_header_access
4898 Usage: reply_header_access header_name allow|deny [!]aclname ...
4900 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4901 this feature could make you liable for problems which it
4904 This option only applies to reply headers, i.e., from the
4905 server to the client.
4907 This is the same as request_header_access, but in the other
4908 direction. Please see request_header_access for detailed
4911 For example, to achieve the same behavior as the old
4912 'http_anonymizer standard' option, you should use:
4914 reply_header_access From deny all
4915 reply_header_access Referer deny all
4916 reply_header_access Server deny all
4917 reply_header_access User-Agent deny all
4918 reply_header_access WWW-Authenticate deny all
4919 reply_header_access Link deny all
4921 Or, to reproduce the old 'http_anonymizer paranoid' feature
4924 reply_header_access Allow allow all
4925 reply_header_access Authorization allow all
4926 reply_header_access WWW-Authenticate allow all
4927 reply_header_access Proxy-Authorization allow all
4928 reply_header_access Proxy-Authenticate allow all
4929 reply_header_access Cache-Control allow all
4930 reply_header_access Content-Encoding allow all
4931 reply_header_access Content-Length allow all
4932 reply_header_access Content-Type allow all
4933 reply_header_access Date allow all
4934 reply_header_access Expires allow all
4935 reply_header_access Host allow all
4936 reply_header_access If-Modified-Since allow all
4937 reply_header_access Last-Modified allow all
4938 reply_header_access Location allow all
4939 reply_header_access Pragma allow all
4940 reply_header_access Accept allow all
4941 reply_header_access Accept-Charset allow all
4942 reply_header_access Accept-Encoding allow all
4943 reply_header_access Accept-Language allow all
4944 reply_header_access Content-Language allow all
4945 reply_header_access Mime-Version allow all
4946 reply_header_access Retry-After allow all
4947 reply_header_access Title allow all
4948 reply_header_access Connection allow all
4949 reply_header_access All deny all
4951 although the HTTP request headers won't be usefully controlled
4952 by this directive -- see request_header_access for details.
4954 By default, all headers are allowed (no anonymizing is
4958 NAME: request_header_replace header_replace
4959 IFDEF: USE_HTTP_VIOLATIONS
4960 TYPE: http_header_replace
4961 LOC: Config.request_header_access
4964 Usage: request_header_replace header_name message
4965 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
4967 This option allows you to change the contents of headers
4968 denied with request_header_access above, by replacing them
4969 with some fixed string. This replaces the old fake_user_agent
4972 This only applies to request headers, not reply headers.
4974 By default, headers are removed if denied.
4977 NAME: reply_header_replace
4978 IFDEF: USE_HTTP_VIOLATIONS
4979 TYPE: http_header_replace
4980 LOC: Config.reply_header_access
4983 Usage: reply_header_replace header_name message
4984 Example: reply_header_replace Server Foo/1.0
4986 This option allows you to change the contents of headers
4987 denied with reply_header_access above, by replacing them
4988 with some fixed string.
4990 This only applies to reply headers, not request headers.
4992 By default, headers are removed if denied.
4995 NAME: request_header_add
4996 TYPE: HeaderWithAclList
4997 LOC: Config.request_header_add
5000 Usage: request_header_add field-name field-value acl1 [acl2] ...
5001 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
5003 This option adds header fields to outgoing HTTP requests (i.e.,
5004 request headers sent by Squid to the next HTTP hop such as a
5005 cache peer or an origin server). The option has no effect during
5006 cache hit detection. The equivalent adaptation vectoring point
5007 in ICAP terminology is post-cache REQMOD.
5009 Field-name is a token specifying an HTTP header name. If a
5010 standard HTTP header name is used, Squid does not check whether
5011 the new header conflicts with any existing headers or violates
5012 HTTP rules. If the request to be modified already contains a
5013 field with the same name, the old field is preserved but the
5014 header field values are not merged.
5016 Field-value is either a token or a quoted string. If quoted
5017 string format is used, then the surrounding quotes are removed
5018 while escape sequences and %macros are processed.
5020 In theory, all of the logformat codes can be used as %macros.
5021 However, unlike logging (which happens at the very end of
5022 transaction lifetime), the transaction may not yet have enough
5023 information to expand a macro when the new header value is needed.
5024 And some information may already be available to Squid but not yet
5025 committed where the macro expansion code can access it (report
5026 such instances!). The macro will be expanded into a single dash
5027 ('-') in such cases. Not all macros have been tested.
5029 One or more Squid ACLs may be specified to restrict header
5030 injection to matching requests. As always in squid.conf, all
5031 ACLs in an option ACL list must be satisfied for the insertion
5032 to happen. The request_header_add option supports fast ACLs
5041 This option used to log custom information about the master
5042 transaction. For example, an admin may configure Squid to log
5043 which "user group" the transaction belongs to, where "user group"
5044 will be determined based on a set of ACLs and not [just]
5045 authentication information.
5046 Values of key/value pairs can be logged using %{key}note macros:
5048 note key value acl ...
5049 logformat myFormat ... %{key}note ...
5052 NAME: relaxed_header_parser
5053 COMMENT: on|off|warn
5055 LOC: Config.onoff.relaxed_header_parser
5058 In the default "on" setting Squid accepts certain forms
5059 of non-compliant HTTP messages where it is unambiguous
5060 what the sending application intended even if the message
5061 is not correctly formatted. The messages is then normalized
5062 to the correct form when forwarded by Squid.
5064 If set to "warn" then a warning will be emitted in cache.log
5065 each time such HTTP error is encountered.
5067 If set to "off" then such HTTP errors will cause the request
5068 or response to be rejected.
5073 -----------------------------------------------------------------------------
5076 NAME: forward_timeout
5079 LOC: Config.Timeout.forward
5082 This parameter specifies how long Squid should at most attempt in
5083 finding a forwarding path for the request before giving up.
5086 NAME: connect_timeout
5089 LOC: Config.Timeout.connect
5092 This parameter specifies how long to wait for the TCP connect to
5093 the requested server or peer to complete before Squid should
5094 attempt to find another path where to forward the request.
5097 NAME: peer_connect_timeout
5100 LOC: Config.Timeout.peer_connect
5103 This parameter specifies how long to wait for a pending TCP
5104 connection to a peer cache. The default is 30 seconds. You
5105 may also set different timeout values for individual neighbors
5106 with the 'connect-timeout' option on a 'cache_peer' line.
5112 LOC: Config.Timeout.read
5115 The read_timeout is applied on server-side connections. After
5116 each successful read(), the timeout will be extended by this
5117 amount. If no data is read again after this amount of time,
5118 the request is aborted and logged with ERR_READ_TIMEOUT. The
5119 default is 15 minutes.
5125 LOC: Config.Timeout.write
5128 This timeout is tracked for all connections that have data
5129 available for writing and are waiting for the socket to become
5130 ready. After each successful write, the timeout is extended by
5131 the configured amount. If Squid has data to write but the
5132 connection is not ready for the configured duration, the
5133 transaction associated with the connection is terminated. The
5134 default is 15 minutes.
5137 NAME: request_timeout
5139 LOC: Config.Timeout.request
5142 How long to wait for complete HTTP request headers after initial
5143 connection establishment.
5146 NAME: client_idle_pconn_timeout persistent_request_timeout
5148 LOC: Config.Timeout.clientIdlePconn
5151 How long to wait for the next HTTP request on a persistent
5152 client connection after the previous request completes.
5155 NAME: client_lifetime
5158 LOC: Config.Timeout.lifetime
5161 The maximum amount of time a client (browser) is allowed to
5162 remain connected to the cache process. This protects the Cache
5163 from having a lot of sockets (and hence file descriptors) tied up
5164 in a CLOSE_WAIT state from remote clients that go away without
5165 properly shutting down (either because of a network failure or
5166 because of a poor client implementation). The default is one
5169 NOTE: The default value is intended to be much larger than any
5170 client would ever need to be connected to your cache. You
5171 should probably change client_lifetime only as a last resort.
5172 If you seem to have many client connections tying up
5173 filedescriptors, we recommend first tuning the read_timeout,
5174 request_timeout, persistent_request_timeout and quick_abort values.
5177 NAME: half_closed_clients
5179 LOC: Config.onoff.half_closed_clients
5182 Some clients may shutdown the sending side of their TCP
5183 connections, while leaving their receiving sides open. Sometimes,
5184 Squid can not tell the difference between a half-closed and a
5185 fully-closed TCP connection.
5187 By default, Squid will immediately close client connections when
5188 read(2) returns "no more data to read."
5190 Change this option to 'on' and Squid will keep open connections
5191 until a read(2) or write(2) on the socket returns an error.
5192 This may show some benefits for reverse proxies. But if not
5193 it is recommended to leave OFF.
5196 NAME: server_idle_pconn_timeout pconn_timeout
5198 LOC: Config.Timeout.serverIdlePconn
5201 Timeout for idle persistent connections to servers and other
5208 LOC: Ident::TheConfig.timeout
5211 Maximum time to wait for IDENT lookups to complete.
5213 If this is too high, and you enabled IDENT lookups from untrusted
5214 users, you might be susceptible to denial-of-service by having
5215 many ident requests going at once.
5218 NAME: shutdown_lifetime
5221 LOC: Config.shutdownLifetime
5224 When SIGTERM or SIGHUP is received, the cache is put into
5225 "shutdown pending" mode until all active sockets are closed.
5226 This value is the lifetime to set for all open descriptors
5227 during shutdown mode. Any active clients after this many
5228 seconds will receive a 'timeout' message.
5232 ADMINISTRATIVE PARAMETERS
5233 -----------------------------------------------------------------------------
5239 LOC: Config.adminEmail
5241 Email-address of local cache manager who will receive
5242 mail if the cache dies. The default is "webmaster."
5248 LOC: Config.EmailFrom
5250 From: email-address for mail sent when the cache dies.
5251 The default is to use 'appname@unique_hostname'.
5252 Default appname value is "squid", can be changed into
5253 src/globals.h before building squid.
5259 LOC: Config.EmailProgram
5261 Email program used to send mail if the cache dies.
5262 The default is "mail". The specified program must comply
5263 with the standard Unix mail syntax:
5264 mail-program recipient < mailfile
5266 Optional command line options can be specified.
5269 NAME: cache_effective_user
5271 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
5272 LOC: Config.effectiveUser
5274 If you start Squid as root, it will change its effective/real
5275 UID/GID to the user specified below. The default is to change
5276 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
5277 see also; cache_effective_group
5280 NAME: cache_effective_group
5283 LOC: Config.effectiveGroup
5285 Squid sets the GID to the effective user's default group ID
5286 (taken from the password file) and supplementary group list
5287 from the groups membership.
5289 If you want Squid to run with a specific GID regardless of
5290 the group memberships of the effective user then set this
5291 to the group (or GID) you want Squid to run as. When set
5292 all other group privileges of the effective user are ignored
5293 and only this GID is effective. If Squid is not started as
5294 root the user starting Squid MUST be member of the specified
5297 This option is not recommended by the Squid Team.
5298 Our preference is for administrators to configure a secure
5299 user account for squid with UID/GID matching system policies.
5302 NAME: httpd_suppress_version_string
5306 LOC: Config.onoff.httpd_suppress_version_string
5308 Suppress Squid version string info in HTTP headers and HTML error pages.
5311 NAME: visible_hostname
5313 LOC: Config.visibleHostname
5316 If you want to present a special hostname in error messages, etc,
5317 define this. Otherwise, the return value of gethostname()
5318 will be used. If you have multiple caches in a cluster and
5319 get errors about IP-forwarding you must set them to have individual
5320 names with this setting.
5323 NAME: unique_hostname
5325 LOC: Config.uniqueHostname
5328 If you want to have multiple machines with the same
5329 'visible_hostname' you must give each machine a different
5330 'unique_hostname' so forwarding loops can be detected.
5333 NAME: hostname_aliases
5335 LOC: Config.hostnameAliases
5338 A list of other DNS names your cache has.
5346 Minimum umask which should be enforced while the proxy
5347 is running, in addition to the umask set at startup.
5349 For a traditional octal representation of umasks, start
5354 OPTIONS FOR THE CACHE REGISTRATION SERVICE
5355 -----------------------------------------------------------------------------
5357 This section contains parameters for the (optional) cache
5358 announcement service. This service is provided to help
5359 cache administrators locate one another in order to join or
5360 create cache hierarchies.
5362 An 'announcement' message is sent (via UDP) to the registration
5363 service by Squid. By default, the announcement message is NOT
5364 SENT unless you enable it with 'announce_period' below.
5366 The announcement message includes your hostname, plus the
5367 following information from this configuration file:
5373 All current information is processed regularly and made
5374 available on the Web at http://www.ircache.net/Cache/Tracker/.
5377 NAME: announce_period
5379 LOC: Config.Announce.period
5382 This is how frequently to send cache announcements. The
5383 default is `0' which disables sending the announcement
5386 To enable announcing your cache, just set an announce period.
5389 announce_period 1 day
5394 DEFAULT: tracker.ircache.net
5395 LOC: Config.Announce.host
5401 LOC: Config.Announce.file
5407 LOC: Config.Announce.port
5409 announce_host and announce_port set the hostname and port
5410 number where the registration message will be sent.
5412 Hostname will default to 'tracker.ircache.net' and port will
5413 default default to 3131. If the 'filename' argument is given,
5414 the contents of that file will be included in the announce
5419 HTTPD-ACCELERATOR OPTIONS
5420 -----------------------------------------------------------------------------
5423 NAME: httpd_accel_surrogate_id
5426 LOC: Config.Accel.surrogate_id
5428 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
5429 need an identification token to allow control targeting. Because
5430 a farm of surrogates may all perform the same tasks, they may share
5431 an identification token.
5433 The default ID is the visible_hostname
5436 NAME: http_accel_surrogate_remote
5440 LOC: Config.onoff.surrogate_is_remote
5442 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
5443 Set this to on to have squid behave as a remote surrogate.
5447 IFDEF: USE_SQUID_ESI
5448 COMMENT: libxml2|expat|custom
5450 LOC: ESIParser::Type
5453 ESI markup is not strictly XML compatible. The custom ESI parser
5454 will give higher performance, but cannot handle non ASCII character
5459 DELAY POOL PARAMETERS
5460 -----------------------------------------------------------------------------
5464 TYPE: delay_pool_count
5466 IFDEF: USE_DELAY_POOLS
5469 This represents the number of delay pools to be used. For example,
5470 if you have one class 2 delay pool and one class 3 delays pool, you
5471 have a total of 2 delay pools.
5475 TYPE: delay_pool_class
5477 IFDEF: USE_DELAY_POOLS
5480 This defines the class of each delay pool. There must be exactly one
5481 delay_class line for each delay pool. For example, to define two
5482 delay pools, one of class 2 and one of class 3, the settings above
5486 delay_pools 4 # 4 delay pools
5487 delay_class 1 2 # pool 1 is a class 2 pool
5488 delay_class 2 3 # pool 2 is a class 3 pool
5489 delay_class 3 4 # pool 3 is a class 4 pool
5490 delay_class 4 5 # pool 4 is a class 5 pool
5492 The delay pool classes are:
5494 class 1 Everything is limited by a single aggregate
5497 class 2 Everything is limited by a single aggregate
5498 bucket as well as an "individual" bucket chosen
5499 from bits 25 through 32 of the IPv4 address.
5501 class 3 Everything is limited by a single aggregate
5502 bucket as well as a "network" bucket chosen
5503 from bits 17 through 24 of the IP address and a
5504 "individual" bucket chosen from bits 17 through
5505 32 of the IPv4 address.
5507 class 4 Everything in a class 3 delay pool, with an
5508 additional limit on a per user basis. This
5509 only takes effect if the username is established
5510 in advance - by forcing authentication in your
5513 class 5 Requests are grouped according their tag (see
5514 external_acl's tag= reply).
5517 Each pool also requires a delay_parameters directive to configure the pool size
5518 and speed limits used whenever the pool is applied to a request. Along with
5519 a set of delay_access directives to determine when it is used.
5521 NOTE: If an IP address is a.b.c.d
5522 -> bits 25 through 32 are "d"
5523 -> bits 17 through 24 are "c"
5524 -> bits 17 through 32 are "c * 256 + d"
5526 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
5527 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
5531 TYPE: delay_pool_access
5533 IFDEF: USE_DELAY_POOLS
5536 This is used to determine which delay pool a request falls into.
5538 delay_access is sorted per pool and the matching starts with pool 1,
5539 then pool 2, ..., and finally pool N. The first delay pool where the
5540 request is allowed is selected for the request. If it does not allow
5541 the request to any pool then the request is not delayed (default).
5543 For example, if you want some_big_clients in delay
5544 pool 1 and lotsa_little_clients in delay pool 2:
5547 delay_access 1 allow some_big_clients
5548 delay_access 1 deny all
5549 delay_access 2 allow lotsa_little_clients
5550 delay_access 2 deny all
5551 delay_access 3 allow authenticated_clients
5554 NAME: delay_parameters
5555 TYPE: delay_pool_rates
5557 IFDEF: USE_DELAY_POOLS
5560 This defines the parameters for a delay pool. Each delay pool has
5561 a number of "buckets" associated with it, as explained in the
5562 description of delay_class.
5564 For a class 1 delay pool, the syntax is:
5566 delay_parameters pool aggregate
5568 For a class 2 delay pool:
5570 delay_parameters pool aggregate individual
5572 For a class 3 delay pool:
5574 delay_parameters pool aggregate network individual
5576 For a class 4 delay pool:
5578 delay_parameters pool aggregate network individual user
5580 For a class 5 delay pool:
5582 delay_parameters pool tagrate
5584 The option variables are:
5586 pool a pool number - ie, a number between 1 and the
5587 number specified in delay_pools as used in
5590 aggregate the speed limit parameters for the aggregate bucket
5593 individual the speed limit parameters for the individual
5594 buckets (class 2, 3).
5596 network the speed limit parameters for the network buckets
5599 user the speed limit parameters for the user buckets
5602 tagrate the speed limit parameters for the tag buckets
5605 A pair of delay parameters is written restore/maximum, where restore is
5606 the number of bytes (not bits - modem and network speeds are usually
5607 quoted in bits) per second placed into the bucket, and maximum is the
5608 maximum number of bytes which can be in the bucket at any time.
5610 There must be one delay_parameters line for each delay pool.
5613 For example, if delay pool number 1 is a class 2 delay pool as in the
5614 above example, and is being used to strictly limit each host to 64Kbit/sec
5615 (plus overheads), with no overall limit, the line is:
5617 delay_parameters 1 -1/-1 8000/8000
5619 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
5621 Note that the figure -1 is used to represent "unlimited".
5624 And, if delay pool number 2 is a class 3 delay pool as in the above
5625 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
5626 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
5627 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
5628 to permit a decent web page to be downloaded at a decent speed
5629 (if the network is not being limited due to overuse) but slow down
5630 large downloads more significantly:
5632 delay_parameters 2 32000/32000 8000/8000 600/8000
5634 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
5635 8 x 8000 KByte/sec -> 64Kbit/sec.
5636 8 x 600 Byte/sec -> 4800bit/sec.
5639 Finally, for a class 4 delay pool as in the example - each user will
5640 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
5642 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
5645 NAME: delay_initial_bucket_level
5646 COMMENT: (percent, 0-100)
5649 IFDEF: USE_DELAY_POOLS
5650 LOC: Config.Delay.initial
5652 The initial bucket percentage is used to determine how much is put
5653 in each bucket when squid starts, is reconfigured, or first notices
5654 a host accessing it (in class 2 and class 3, individual hosts and
5655 networks only have buckets associated with them once they have been
5660 CLIENT DELAY POOL PARAMETERS
5661 -----------------------------------------------------------------------------
5664 NAME: client_delay_pools
5665 TYPE: client_delay_pool_count
5667 IFDEF: USE_DELAY_POOLS
5668 LOC: Config.ClientDelay
5670 This option specifies the number of client delay pools used. It must
5671 preceed other client_delay_* options.
5674 client_delay_pools 2
5677 NAME: client_delay_initial_bucket_level
5678 COMMENT: (percent, 0-no_limit)
5681 IFDEF: USE_DELAY_POOLS
5682 LOC: Config.ClientDelay.initial
5684 This option determines the initial bucket size as a percentage of
5685 max_bucket_size from client_delay_parameters. Buckets are created
5686 at the time of the "first" connection from the matching IP. Idle
5687 buckets are periodically deleted up.
5689 You can specify more than 100 percent but note that such "oversized"
5690 buckets are not refilled until their size goes down to max_bucket_size
5691 from client_delay_parameters.
5694 client_delay_initial_bucket_level 50
5697 NAME: client_delay_parameters
5698 TYPE: client_delay_pool_rates
5700 IFDEF: USE_DELAY_POOLS
5701 LOC: Config.ClientDelay
5704 This option configures client-side bandwidth limits using the
5707 client_delay_parameters pool speed_limit max_bucket_size
5709 pool is an integer ID used for client_delay_access matching.
5711 speed_limit is bytes added to the bucket per second.
5713 max_bucket_size is the maximum size of a bucket, enforced after any
5714 speed_limit additions.
5716 Please see the delay_parameters option for more information and
5720 client_delay_parameters 1 1024 2048
5721 client_delay_parameters 2 51200 16384
5724 NAME: client_delay_access
5725 TYPE: client_delay_pool_access
5727 IFDEF: USE_DELAY_POOLS
5728 LOC: Config.ClientDelay
5731 This option determines the client-side delay pool for the
5734 client_delay_access pool_ID allow|deny acl_name
5736 All client_delay_access options are checked in their pool ID
5737 order, starting with pool 1. The first checked pool with allowed
5738 request is selected for the request. If no ACL matches or there
5739 are no client_delay_access options, the request bandwidth is not
5742 The ACL-selected pool is then used to find the
5743 client_delay_parameters for the request. Client-side pools are
5744 not used to aggregate clients. Clients are always aggregated
5745 based on their source IP addresses (one bucket per source IP).
5747 Please see delay_access for more examples.
5750 client_delay_access 1 allow low_rate_network
5751 client_delay_access 2 allow vips_network
5755 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
5756 -----------------------------------------------------------------------------
5761 LOC: Config.Wccp.router
5765 Use this option to define your WCCP ``home'' router for
5768 wccp_router supports a single WCCP(v1) router
5770 wccp2_router supports multiple WCCPv2 routers
5772 only one of the two may be used at the same time and defines
5773 which version of WCCP to use.
5777 TYPE: IpAddress_list
5778 LOC: Config.Wccp2.router
5782 Use this option to define your WCCP ``home'' router for
5785 wccp_router supports a single WCCP(v1) router
5787 wccp2_router supports multiple WCCPv2 routers
5789 only one of the two may be used at the same time and defines
5790 which version of WCCP to use.
5795 LOC: Config.Wccp.version
5799 This directive is only relevant if you need to set up WCCP(v1)
5800 to some very old and end-of-life Cisco routers. In all other
5801 setups it must be left unset or at the default setting.
5802 It defines an internal version in the WCCP(v1) protocol,
5803 with version 4 being the officially documented protocol.
5805 According to some users, Cisco IOS 11.2 and earlier only
5806 support WCCP version 3. If you're using that or an earlier
5807 version of IOS, you may need to change this value to 3, otherwise
5808 do not specify this parameter.
5811 NAME: wccp2_rebuild_wait
5813 LOC: Config.Wccp2.rebuildwait
5817 If this is enabled Squid will wait for the cache dir rebuild to finish
5818 before sending the first wccp2 HereIAm packet
5821 NAME: wccp2_forwarding_method
5823 LOC: Config.Wccp2.forwarding_method
5827 WCCP2 allows the setting of forwarding methods between the
5828 router/switch and the cache. Valid values are as follows:
5830 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5831 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5833 Currently (as of IOS 12.4) cisco routers only support GRE.
5834 Cisco switches only support the L2 redirect assignment method.
5837 NAME: wccp2_return_method
5839 LOC: Config.Wccp2.return_method
5843 WCCP2 allows the setting of return methods between the
5844 router/switch and the cache for packets that the cache
5845 decides not to handle. Valid values are as follows:
5847 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5848 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5850 Currently (as of IOS 12.4) cisco routers only support GRE.
5851 Cisco switches only support the L2 redirect assignment.
5853 If the "ip wccp redirect exclude in" command has been
5854 enabled on the cache interface, then it is still safe for
5855 the proxy server to use a l2 redirect method even if this
5856 option is set to GRE.
5859 NAME: wccp2_assignment_method
5861 LOC: Config.Wccp2.assignment_method
5865 WCCP2 allows the setting of methods to assign the WCCP hash
5866 Valid values are as follows:
5868 hash - Hash assignment
5869 mask - Mask assignment
5871 As a general rule, cisco routers support the hash assignment method
5872 and cisco switches support the mask assignment method.
5877 LOC: Config.Wccp2.info
5878 DEFAULT_IF_NONE: standard 0
5881 WCCP2 allows for multiple traffic services. There are two
5882 types: "standard" and "dynamic". The standard type defines
5883 one service id - http (id 0). The dynamic service ids can be from
5884 51 to 255 inclusive. In order to use a dynamic service id
5885 one must define the type of traffic to be redirected; this is done
5886 using the wccp2_service_info option.
5888 The "standard" type does not require a wccp2_service_info option,
5889 just specifying the service id will suffice.
5891 MD5 service authentication can be enabled by adding
5892 "password=<password>" to the end of this service declaration.
5896 wccp2_service standard 0 # for the 'web-cache' standard service
5897 wccp2_service dynamic 80 # a dynamic service type which will be
5898 # fleshed out with subsequent options.
5899 wccp2_service standard 0 password=foo
5902 NAME: wccp2_service_info
5903 TYPE: wccp2_service_info
5904 LOC: Config.Wccp2.info
5908 Dynamic WCCPv2 services require further information to define the
5909 traffic you wish to have diverted.
5913 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
5914 priority=<priority> ports=<port>,<port>..
5916 The relevant WCCPv2 flags:
5917 + src_ip_hash, dst_ip_hash
5918 + source_port_hash, dst_port_hash
5919 + src_ip_alt_hash, dst_ip_alt_hash
5920 + src_port_alt_hash, dst_port_alt_hash
5923 The port list can be one to eight entries.
5927 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
5928 priority=240 ports=80
5930 Note: the service id must have been defined by a previous
5931 'wccp2_service dynamic <id>' entry.
5936 LOC: Config.Wccp2.weight
5940 Each cache server gets assigned a set of the destination
5941 hash proportional to their weight.
5946 LOC: Config.Wccp.address
5953 LOC: Config.Wccp2.address
5957 Use this option if you require WCCP to use a specific
5960 The default behavior is to not bind to any specific address.
5964 PERSISTENT CONNECTION HANDLING
5965 -----------------------------------------------------------------------------
5967 Also see "pconn_timeout" in the TIMEOUTS section
5970 NAME: client_persistent_connections
5972 LOC: Config.onoff.client_pconns
5976 NAME: server_persistent_connections
5978 LOC: Config.onoff.server_pconns
5981 Persistent connection support for clients and servers. By
5982 default, Squid uses persistent connections (when allowed)
5983 with its clients and servers. You can use these options to
5984 disable persistent connections with clients and/or servers.
5987 NAME: persistent_connection_after_error
5989 LOC: Config.onoff.error_pconns
5992 With this directive the use of persistent connections after
5993 HTTP errors can be disabled. Useful if you have clients
5994 who fail to handle errors on persistent connections proper.
5997 NAME: detect_broken_pconn
5999 LOC: Config.onoff.detect_broken_server_pconns
6002 Some servers have been found to incorrectly signal the use
6003 of HTTP/1.0 persistent connections even on replies not
6004 compatible, causing significant delays. This server problem
6005 has mostly been seen on redirects.
6007 By enabling this directive Squid attempts to detect such
6008 broken replies and automatically assume the reply is finished
6009 after 10 seconds timeout.
6013 CACHE DIGEST OPTIONS
6014 -----------------------------------------------------------------------------
6017 NAME: digest_generation
6018 IFDEF: USE_CACHE_DIGESTS
6020 LOC: Config.onoff.digest_generation
6023 This controls whether the server will generate a Cache Digest
6024 of its contents. By default, Cache Digest generation is
6025 enabled if Squid is compiled with --enable-cache-digests defined.
6028 NAME: digest_bits_per_entry
6029 IFDEF: USE_CACHE_DIGESTS
6031 LOC: Config.digest.bits_per_entry
6034 This is the number of bits of the server's Cache Digest which
6035 will be associated with the Digest entry for a given HTTP
6036 Method and URL (public key) combination. The default is 5.
6039 NAME: digest_rebuild_period
6040 IFDEF: USE_CACHE_DIGESTS
6043 LOC: Config.digest.rebuild_period
6046 This is the wait time between Cache Digest rebuilds.
6049 NAME: digest_rewrite_period
6051 IFDEF: USE_CACHE_DIGESTS
6053 LOC: Config.digest.rewrite_period
6056 This is the wait time between Cache Digest writes to
6060 NAME: digest_swapout_chunk_size
6063 IFDEF: USE_CACHE_DIGESTS
6064 LOC: Config.digest.swapout_chunk_size
6067 This is the number of bytes of the Cache Digest to write to
6068 disk at a time. It defaults to 4096 bytes (4KB), the Squid
6072 NAME: digest_rebuild_chunk_percentage
6073 COMMENT: (percent, 0-100)
6074 IFDEF: USE_CACHE_DIGESTS
6076 LOC: Config.digest.rebuild_chunk_percentage
6079 This is the percentage of the Cache Digest to be scanned at a
6080 time. By default it is set to 10% of the Cache Digest.
6085 -----------------------------------------------------------------------------
6090 LOC: Config.Port.snmp
6094 The port number where Squid listens for SNMP requests. To enable
6095 SNMP support set this to a suitable port number. Port number
6096 3401 is often used for the Squid SNMP agent. By default it's
6097 set to "0" (disabled)
6105 LOC: Config.accessList.snmp
6106 DEFAULT_IF_NONE: deny all
6109 Allowing or denying access to the SNMP port.
6111 All access to the agent is denied by default.
6114 snmp_access allow|deny [!]aclname ...
6116 This clause only supports fast acl types.
6117 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6119 snmp_access allow snmppublic localhost
6120 snmp_access deny all
6123 NAME: snmp_incoming_address
6125 LOC: Config.Addrs.snmp_incoming
6130 NAME: snmp_outgoing_address
6132 LOC: Config.Addrs.snmp_outgoing
6136 Just like 'udp_incoming_address', but for the SNMP port.
6138 snmp_incoming_address is used for the SNMP socket receiving
6139 messages from SNMP agents.
6140 snmp_outgoing_address is used for SNMP packets returned to SNMP
6143 The default snmp_incoming_address is to listen on all
6144 available network interfaces.
6146 If snmp_outgoing_address is not set it will use the same socket
6147 as snmp_incoming_address. Only change this if you want to have
6148 SNMP replies sent using another address than where this Squid
6149 listens for SNMP queries.
6151 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
6152 the same value since they both use port 3401.
6157 -----------------------------------------------------------------------------
6160 NAME: icp_port udp_port
6163 LOC: Config.Port.icp
6165 The port number where Squid sends and receives ICP queries to
6166 and from neighbor caches. The standard UDP port for ICP is 3130.
6167 Default is disabled (0).
6170 icp_port @DEFAULT_ICP_PORT@
6177 LOC: Config.Port.htcp
6179 The port number where Squid sends and receives HTCP queries to
6180 and from neighbor caches. To turn it on you want to set it to
6181 4827. By default it is set to "0" (disabled).
6187 NAME: log_icp_queries
6191 LOC: Config.onoff.log_udp
6193 If set, ICP queries are logged to access.log. You may wish
6194 do disable this if your ICP load is VERY high to speed things
6195 up or to simplify log analysis.
6198 NAME: udp_incoming_address
6200 LOC:Config.Addrs.udp_incoming
6203 udp_incoming_address is used for UDP packets received from other
6206 The default behavior is to not bind to any specific address.
6208 Only change this if you want to have all UDP queries received on
6209 a specific interface/address.
6211 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
6212 modules. Altering it will affect all of them in the same manner.
6214 see also; udp_outgoing_address
6216 NOTE, udp_incoming_address and udp_outgoing_address can not
6217 have the same value since they both use the same port.
6220 NAME: udp_outgoing_address
6222 LOC: Config.Addrs.udp_outgoing
6225 udp_outgoing_address is used for UDP packets sent out to other
6228 The default behavior is to not bind to any specific address.
6230 Instead it will use the same socket as udp_incoming_address.
6231 Only change this if you want to have UDP queries sent using another
6232 address than where this Squid listens for UDP queries from other
6235 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
6236 modules. Altering it will affect all of them in the same manner.
6238 see also; udp_incoming_address
6240 NOTE, udp_incoming_address and udp_outgoing_address can not
6241 have the same value since they both use the same port.
6248 LOC: Config.onoff.icp_hit_stale
6250 If you want to return ICP_HIT for stale cache objects, set this
6251 option to 'on'. If you have sibling relationships with caches
6252 in other administrative domains, this should be 'off'. If you only
6253 have sibling relationships with caches under your control,
6254 it is probably okay to set this to 'on'.
6255 If set to 'on', your siblings should use the option "allow-miss"
6256 on their cache_peer lines for connecting to you.
6259 NAME: minimum_direct_hops
6262 LOC: Config.minDirectHops
6264 If using the ICMP pinging stuff, do direct fetches for sites
6265 which are no more than this many hops away.
6268 NAME: minimum_direct_rtt
6271 LOC: Config.minDirectRtt
6273 If using the ICMP pinging stuff, do direct fetches for sites
6274 which are no more than this many rtt milliseconds away.
6280 LOC: Config.Netdb.low
6286 LOC: Config.Netdb.high
6288 The low and high water marks for the ICMP measurement
6289 database. These are counts, not percents. The defaults are
6290 900 and 1000. When the high water mark is reached, database
6291 entries will be deleted until the low mark is reached.
6294 NAME: netdb_ping_period
6296 LOC: Config.Netdb.period
6299 The minimum period for measuring a site. There will be at
6300 least this much delay between successive pings to the same
6301 network. The default is five minutes.
6308 LOC: Config.onoff.query_icmp
6310 If you want to ask your peers to include ICMP data in their ICP
6311 replies, enable this option.
6313 If your peer has configured Squid (during compilation) with
6314 '--enable-icmp' that peer will send ICMP pings to origin server
6315 sites of the URLs it receives. If you enable this option the
6316 ICP replies from that peer will include the ICMP data (if available).
6317 Then, when choosing a parent cache, Squid will choose the parent with
6318 the minimal RTT to the origin server. When this happens, the
6319 hierarchy field of the access.log will be
6320 "CLOSEST_PARENT_MISS". This option is off by default.
6323 NAME: test_reachability
6327 LOC: Config.onoff.test_reachability
6329 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
6330 instead of ICP_MISS if the target host is NOT in the ICMP
6331 database, or has a zero RTT.
6334 NAME: icp_query_timeout
6338 LOC: Config.Timeout.icp_query
6340 Normally Squid will automatically determine an optimal ICP
6341 query timeout value based on the round-trip-time of recent ICP
6342 queries. If you want to override the value determined by
6343 Squid, set this 'icp_query_timeout' to a non-zero value. This
6344 value is specified in MILLISECONDS, so, to use a 2-second
6345 timeout (the old default), you would write:
6347 icp_query_timeout 2000
6350 NAME: maximum_icp_query_timeout
6354 LOC: Config.Timeout.icp_query_max
6356 Normally the ICP query timeout is determined dynamically. But
6357 sometimes it can lead to very large values (say 5 seconds).
6358 Use this option to put an upper limit on the dynamic timeout
6359 value. Do NOT use this option to always use a fixed (instead
6360 of a dynamic) timeout value. To set a fixed timeout see the
6361 'icp_query_timeout' directive.
6364 NAME: minimum_icp_query_timeout
6368 LOC: Config.Timeout.icp_query_min
6370 Normally the ICP query timeout is determined dynamically. But
6371 sometimes it can lead to very small timeouts, even lower than
6372 the normal latency variance on your link due to traffic.
6373 Use this option to put an lower limit on the dynamic timeout
6374 value. Do NOT use this option to always use a fixed (instead
6375 of a dynamic) timeout value. To set a fixed timeout see the
6376 'icp_query_timeout' directive.
6379 NAME: background_ping_rate
6383 LOC: Config.backgroundPingRate
6385 Controls how often the ICP pings are sent to siblings that
6386 have background-ping set.
6390 MULTICAST ICP OPTIONS
6391 -----------------------------------------------------------------------------
6396 LOC: Config.mcast_group_list
6399 This tag specifies a list of multicast groups which your server
6400 should join to receive multicasted ICP queries.
6402 NOTE! Be very careful what you put here! Be sure you
6403 understand the difference between an ICP _query_ and an ICP
6404 _reply_. This option is to be set only if you want to RECEIVE
6405 multicast queries. Do NOT set this option to SEND multicast
6406 ICP (use cache_peer for that). ICP replies are always sent via
6407 unicast, so this option does not affect whether or not you will
6408 receive replies from multicast group members.
6410 You must be very careful to NOT use a multicast address which
6411 is already in use by another group of caches.
6413 If you are unsure about multicast, please read the Multicast
6414 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
6416 Usage: mcast_groups 239.128.16.128 224.0.1.20
6418 By default, Squid doesn't listen on any multicast groups.
6421 NAME: mcast_miss_addr
6422 IFDEF: MULTICAST_MISS_STREAM
6424 LOC: Config.mcast_miss.addr
6427 If you enable this option, every "cache miss" URL will
6428 be sent out on the specified multicast address.
6430 Do not enable this option unless you are are absolutely
6431 certain you understand what you are doing.
6434 NAME: mcast_miss_ttl
6435 IFDEF: MULTICAST_MISS_STREAM
6437 LOC: Config.mcast_miss.ttl
6440 This is the time-to-live value for packets multicasted
6441 when multicasting off cache miss URLs is enabled. By
6442 default this is set to 'site scope', i.e. 16.
6445 NAME: mcast_miss_port
6446 IFDEF: MULTICAST_MISS_STREAM
6448 LOC: Config.mcast_miss.port
6451 This is the port number to be used in conjunction with
6455 NAME: mcast_miss_encode_key
6456 IFDEF: MULTICAST_MISS_STREAM
6458 LOC: Config.mcast_miss.encode_key
6459 DEFAULT: XXXXXXXXXXXXXXXX
6461 The URLs that are sent in the multicast miss stream are
6462 encrypted. This is the encryption key.
6465 NAME: mcast_icp_query_timeout
6469 LOC: Config.Timeout.mcast_icp_query
6471 For multicast peers, Squid regularly sends out ICP "probes" to
6472 count how many other peers are listening on the given multicast
6473 address. This value specifies how long Squid should wait to
6474 count all the replies. The default is 2000 msec, or 2
6479 INTERNAL ICON OPTIONS
6480 -----------------------------------------------------------------------------
6483 NAME: icon_directory
6485 LOC: Config.icons.directory
6486 DEFAULT: @DEFAULT_ICON_DIR@
6488 Where the icons are stored. These are normally kept in
6492 NAME: global_internal_static
6494 LOC: Config.onoff.global_internal_static
6497 This directive controls is Squid should intercept all requests for
6498 /squid-internal-static/ no matter which host the URL is requesting
6499 (default on setting), or if nothing special should be done for
6500 such URLs (off setting). The purpose of this directive is to make
6501 icons etc work better in complex cache hierarchies where it may
6502 not always be possible for all corners in the cache mesh to reach
6503 the server generating a directory listing.
6506 NAME: short_icon_urls
6508 LOC: Config.icons.use_short_names
6511 If this is enabled Squid will use short URLs for icons.
6512 If disabled it will revert to the old behavior of including
6513 it's own name and port in the URL.
6515 If you run a complex cache hierarchy with a mix of Squid and
6516 other proxies you may need to disable this directive.
6521 -----------------------------------------------------------------------------
6524 NAME: error_directory
6526 LOC: Config.errorDirectory
6529 If you wish to create your own versions of the default
6530 error files to customize them to suit your company copy
6531 the error/template files to another directory and point
6534 WARNING: This option will disable multi-language support
6535 on error pages if used.
6537 The squid developers are interested in making squid available in
6538 a wide variety of languages. If you are making translations for a
6539 language that Squid does not currently provide please consider
6540 contributing your translation back to the project.
6541 http://wiki.squid-cache.org/Translations
6543 The squid developers working on translations are happy to supply drop-in
6544 translated error files in exchange for any new language contributions.
6547 NAME: error_default_language
6548 IFDEF: USE_ERR_LOCALES
6550 LOC: Config.errorDefaultLanguage
6553 Set the default language which squid will send error pages in
6554 if no existing translation matches the clients language
6557 If unset (default) generic English will be used.
6559 The squid developers are interested in making squid available in
6560 a wide variety of languages. If you are interested in making
6561 translations for any language see the squid wiki for details.
6562 http://wiki.squid-cache.org/Translations
6565 NAME: error_log_languages
6566 IFDEF: USE_ERR_LOCALES
6568 LOC: Config.errorLogMissingLanguages
6571 Log to cache.log what languages users are attempting to
6572 auto-negotiate for translations.
6574 Successful negotiations are not logged. Only failures
6575 have meaning to indicate that Squid may need an upgrade
6576 of its error page translations.
6579 NAME: err_page_stylesheet
6581 LOC: Config.errorStylesheet
6582 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
6584 CSS Stylesheet to pattern the display of Squid default error pages.
6586 For information on CSS see http://www.w3.org/Style/CSS/
6591 LOC: Config.errHtmlText
6594 HTML text to include in error messages. Make this a "mailto"
6595 URL to your admin address, or maybe just a link to your
6596 organizations Web page.
6598 To include this in your error messages, you must rewrite
6599 the error template files (found in the "errors" directory).
6600 Wherever you want the 'err_html_text' line to appear,
6601 insert a %L tag in the error template file.
6604 NAME: email_err_data
6607 LOC: Config.onoff.emailErrData
6610 If enabled, information about the occurred error will be
6611 included in the mailto links of the ERR pages (if %W is set)
6612 so that the email body contains the data.
6613 Syntax is <A HREF="mailto:%w%W">%w</A>
6618 LOC: Config.denyInfoList
6621 Usage: deny_info err_page_name acl
6622 or deny_info http://... acl
6623 or deny_info TCP_RESET acl
6625 This can be used to return a ERR_ page for requests which
6626 do not pass the 'http_access' rules. Squid remembers the last
6627 acl it evaluated in http_access, and if a 'deny_info' line exists
6628 for that ACL Squid returns a corresponding error page.
6630 The acl is typically the last acl on the http_access deny line which
6631 denied access. The exceptions to this rule are:
6632 - When Squid needs to request authentication credentials. It's then
6633 the first authentication related acl encountered
6634 - When none of the http_access lines matches. It's then the last
6635 acl processed on the last http_access line.
6636 - When the decision to deny access was made by an adaptation service,
6637 the acl name is the corresponding eCAP or ICAP service_name.
6639 NP: If providing your own custom error pages with error_directory
6640 you may also specify them by your custom file name:
6641 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
6643 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
6644 may be specified by prefixing the file name with the code and a colon.
6645 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
6647 Alternatively you can tell Squid to reset the TCP connection
6648 by specifying TCP_RESET.
6650 Or you can specify an error URL or URL pattern. The browsers will
6651 get redirected to the specified URL after formatting tags have
6652 been replaced. Redirect will be done with 302 or 307 according to
6653 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
6654 the URL. e.g. 303:http://example.com/
6657 %a - username (if available. Password NOT included)
6660 %E - Error description
6662 %H - Request domain name
6663 %i - Client IP Address
6665 %o - Message result from external ACL helper
6666 %p - Request Port number
6667 %P - Request Protocol name
6668 %R - Request URL path
6669 %T - Timestamp in RFC 1123 format
6670 %U - Full canonical URL from client
6671 (HTTPS URLs terminate with *)
6672 %u - Full canonical URL from client
6673 %w - Admin email from squid.conf
6675 %% - Literal percent (%) code
6680 OPTIONS INFLUENCING REQUEST FORWARDING
6681 -----------------------------------------------------------------------------
6684 NAME: nonhierarchical_direct
6686 LOC: Config.onoff.nonhierarchical_direct
6689 By default, Squid will send any non-hierarchical requests
6690 (matching hierarchy_stoplist or not cacheable request type) direct
6693 If you set this to off, Squid will prefer to send these
6694 requests to parents.
6696 Note that in most configurations, by turning this off you will only
6697 add latency to these request without any improvement in global hit
6700 If you are inside an firewall see never_direct instead of
6706 LOC: Config.onoff.prefer_direct
6709 Normally Squid tries to use parents for most requests. If you for some
6710 reason like it to first try going direct and only use a parent if
6711 going direct fails set this to on.
6713 By combining nonhierarchical_direct off and prefer_direct on you
6714 can set up Squid to use a parent as a backup path if going direct
6717 Note: If you want Squid to use parents for all requests see
6718 the never_direct directive. prefer_direct only modifies how Squid
6719 acts on cacheable requests.
6724 LOC: Config.accessList.AlwaysDirect
6727 Usage: always_direct allow|deny [!]aclname ...
6729 Here you can use ACL elements to specify requests which should
6730 ALWAYS be forwarded by Squid to the origin servers without using
6731 any peers. For example, to always directly forward requests for
6732 local servers ignoring any parents or siblings you may have use
6735 acl local-servers dstdomain my.domain.net
6736 always_direct allow local-servers
6738 To always forward FTP requests directly, use
6741 always_direct allow FTP
6743 NOTE: There is a similar, but opposite option named
6744 'never_direct'. You need to be aware that "always_direct deny
6745 foo" is NOT the same thing as "never_direct allow foo". You
6746 may need to use a deny rule to exclude a more-specific case of
6747 some other rule. Example:
6749 acl local-external dstdomain external.foo.net
6750 acl local-servers dstdomain .foo.net
6751 always_direct deny local-external
6752 always_direct allow local-servers
6754 NOTE: If your goal is to make the client forward the request
6755 directly to the origin server bypassing Squid then this needs
6756 to be done in the client configuration. Squid configuration
6757 can only tell Squid how Squid should fetch the object.
6759 NOTE: This directive is not related to caching. The replies
6760 is cached as usual even if you use always_direct. To not cache
6761 the replies see the 'cache' directive.
6763 This clause supports both fast and slow acl types.
6764 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6769 LOC: Config.accessList.NeverDirect
6772 Usage: never_direct allow|deny [!]aclname ...
6774 never_direct is the opposite of always_direct. Please read
6775 the description for always_direct if you have not already.
6777 With 'never_direct' you can use ACL elements to specify
6778 requests which should NEVER be forwarded directly to origin
6779 servers. For example, to force the use of a proxy for all
6780 requests, except those in your local domain use something like:
6782 acl local-servers dstdomain .foo.net
6783 never_direct deny local-servers
6784 never_direct allow all
6786 or if Squid is inside a firewall and there are local intranet
6787 servers inside the firewall use something like:
6789 acl local-intranet dstdomain .foo.net
6790 acl local-external dstdomain external.foo.net
6791 always_direct deny local-external
6792 always_direct allow local-intranet
6793 never_direct allow all
6795 This clause supports both fast and slow acl types.
6796 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6800 ADVANCED NETWORKING OPTIONS
6801 -----------------------------------------------------------------------------
6804 NAME: incoming_udp_average incoming_icp_average
6807 LOC: Config.comm_incoming.udp.average
6809 Heavy voodoo here. I can't even believe you are reading this.
6810 Are you crazy? Don't even think about adjusting these unless
6811 you understand the algorithms in comm_select.c first!
6814 NAME: incoming_tcp_average incoming_http_average
6817 LOC: Config.comm_incoming.tcp.average
6819 Heavy voodoo here. I can't even believe you are reading this.
6820 Are you crazy? Don't even think about adjusting these unless
6821 you understand the algorithms in comm_select.c first!
6824 NAME: incoming_dns_average
6827 LOC: Config.comm_incoming.dns.average
6829 Heavy voodoo here. I can't even believe you are reading this.
6830 Are you crazy? Don't even think about adjusting these unless
6831 you understand the algorithms in comm_select.c first!
6834 NAME: min_udp_poll_cnt min_icp_poll_cnt
6837 LOC: Config.comm_incoming.udp.min_poll
6839 Heavy voodoo here. I can't even believe you are reading this.
6840 Are you crazy? Don't even think about adjusting these unless
6841 you understand the algorithms in comm_select.c first!
6844 NAME: min_dns_poll_cnt
6847 LOC: Config.comm_incoming.dns.min_poll
6849 Heavy voodoo here. I can't even believe you are reading this.
6850 Are you crazy? Don't even think about adjusting these unless
6851 you understand the algorithms in comm_select.c first!
6854 NAME: min_tcp_poll_cnt min_http_poll_cnt
6857 LOC: Config.comm_incoming.tcp.min_poll
6859 Heavy voodoo here. I can't even believe you are reading this.
6860 Are you crazy? Don't even think about adjusting these unless
6861 you understand the algorithms in comm_select.c first!
6867 LOC: Config.accept_filter
6871 The name of an accept(2) filter to install on Squid's
6872 listen socket(s). This feature is perhaps specific to
6873 FreeBSD and requires support in the kernel.
6875 The 'httpready' filter delays delivering new connections
6876 to Squid until a full HTTP request has been received.
6877 See the accf_http(9) man page for details.
6879 The 'dataready' filter delays delivering new connections
6880 to Squid until there is some data to process.
6881 See the accf_dataready(9) man page for details.
6885 The 'data' filter delays delivering of new connections
6886 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
6887 You may optionally specify a number of seconds to wait by
6888 'data=N' where N is the number of seconds. Defaults to 30
6889 if not specified. See the tcp(7) man page for details.
6892 accept_filter httpready
6897 NAME: client_ip_max_connections
6899 LOC: Config.client_ip_max_connections
6902 Set an absolute limit on the number of connections a single
6903 client IP can use. Any more than this and Squid will begin to drop
6904 new connections from the client until it closes some links.
6906 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
6907 connections from the client. For finer control use the ACL access controls.
6909 Requires client_db to be enabled (the default).
6911 WARNING: This may noticably slow down traffic received via external proxies
6912 or NAT devices and cause them to rebound error messages back to their clients.
6915 NAME: tcp_recv_bufsize
6919 LOC: Config.tcpRcvBufsz
6921 Size of receive buffer to set for TCP sockets. Probably just
6922 as easy to change your kernel's default. Set to zero to use
6923 the default buffer size.
6928 -----------------------------------------------------------------------------
6935 LOC: Adaptation::Icap::TheConfig.onoff
6938 If you want to enable the ICAP module support, set this to on.
6941 NAME: icap_connect_timeout
6944 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
6947 This parameter specifies how long to wait for the TCP connect to
6948 the requested ICAP server to complete before giving up and either
6949 terminating the HTTP transaction or bypassing the failure.
6951 The default for optional services is peer_connect_timeout.
6952 The default for essential services is connect_timeout.
6953 If this option is explicitly set, its value applies to all services.
6956 NAME: icap_io_timeout
6960 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
6963 This parameter specifies how long to wait for an I/O activity on
6964 an established, active ICAP connection before giving up and
6965 either terminating the HTTP transaction or bypassing the
6968 The default is read_timeout.
6971 NAME: icap_service_failure_limit
6972 COMMENT: limit [in memory-depth time-units]
6973 TYPE: icap_service_failure_limit
6975 LOC: Adaptation::Icap::TheConfig
6978 The limit specifies the number of failures that Squid tolerates
6979 when establishing a new TCP connection with an ICAP service. If
6980 the number of failures exceeds the limit, the ICAP service is
6981 not used for new ICAP requests until it is time to refresh its
6984 A negative value disables the limit. Without the limit, an ICAP
6985 service will not be considered down due to connectivity failures
6986 between ICAP OPTIONS requests.
6988 Squid forgets ICAP service failures older than the specified
6989 value of memory-depth. The memory fading algorithm
6990 is approximate because Squid does not remember individual
6991 errors but groups them instead, splitting the option
6992 value into ten time slots of equal length.
6994 When memory-depth is 0 and by default this option has no
6995 effect on service failure expiration.
6997 Squid always forgets failures when updating service settings
6998 using an ICAP OPTIONS transaction, regardless of this option
7002 # suspend service usage after 10 failures in 5 seconds:
7003 icap_service_failure_limit 10 in 5 seconds
7006 NAME: icap_service_revival_delay
7009 LOC: Adaptation::Icap::TheConfig.service_revival_delay
7012 The delay specifies the number of seconds to wait after an ICAP
7013 OPTIONS request failure before requesting the options again. The
7014 failed ICAP service is considered "down" until fresh OPTIONS are
7017 The actual delay cannot be smaller than the hardcoded minimum
7018 delay of 30 seconds.
7021 NAME: icap_preview_enable
7025 LOC: Adaptation::Icap::TheConfig.preview_enable
7028 The ICAP Preview feature allows the ICAP server to handle the
7029 HTTP message by looking only at the beginning of the message body
7030 or even without receiving the body at all. In some environments,
7031 previews greatly speedup ICAP processing.
7033 During an ICAP OPTIONS transaction, the server may tell Squid what
7034 HTTP messages should be previewed and how big the preview should be.
7035 Squid will not use Preview if the server did not request one.
7037 To disable ICAP Preview for all ICAP services, regardless of
7038 individual ICAP server OPTIONS responses, set this option to "off".
7040 icap_preview_enable off
7043 NAME: icap_preview_size
7046 LOC: Adaptation::Icap::TheConfig.preview_size
7049 The default size of preview data to be sent to the ICAP server.
7050 -1 means no preview. This value might be overwritten on a per server
7051 basis by OPTIONS requests.
7054 NAME: icap_206_enable
7058 LOC: Adaptation::Icap::TheConfig.allow206_enable
7061 206 (Partial Content) responses is an ICAP extension that allows the
7062 ICAP agents to optionally combine adapted and original HTTP message
7063 content. The decision to combine is postponed until the end of the
7064 ICAP response. Squid supports Partial Content extension by default.
7066 Activation of the Partial Content extension is negotiated with each
7067 ICAP service during OPTIONS exchange. Most ICAP servers should handle
7068 negotation correctly even if they do not support the extension, but
7069 some might fail. To disable Partial Content support for all ICAP
7070 services and to avoid any negotiation, set this option to "off".
7076 NAME: icap_default_options_ttl
7079 LOC: Adaptation::Icap::TheConfig.default_options_ttl
7082 The default TTL value for ICAP OPTIONS responses that don't have
7083 an Options-TTL header.
7086 NAME: icap_persistent_connections
7090 LOC: Adaptation::Icap::TheConfig.reuse_connections
7093 Whether or not Squid should use persistent connections to
7097 NAME: adaptation_send_client_ip icap_send_client_ip
7099 IFDEF: USE_ADAPTATION
7101 LOC: Adaptation::Config::send_client_ip
7104 If enabled, Squid shares HTTP client IP information with adaptation
7105 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
7106 For eCAP, Squid sets the libecap::metaClientIp transaction option.
7108 See also: adaptation_uses_indirect_client
7111 NAME: adaptation_send_username icap_send_client_username
7113 IFDEF: USE_ADAPTATION
7115 LOC: Adaptation::Config::send_username
7118 This sends authenticated HTTP client username (if available) to
7119 the adaptation service.
7121 For ICAP, the username value is encoded based on the
7122 icap_client_username_encode option and is sent using the header
7123 specified by the icap_client_username_header option.
7126 NAME: icap_client_username_header
7129 LOC: Adaptation::Icap::TheConfig.client_username_header
7130 DEFAULT: X-Client-Username
7132 ICAP request header name to use for adaptation_send_username.
7135 NAME: icap_client_username_encode
7139 LOC: Adaptation::Icap::TheConfig.client_username_encode
7142 Whether to base64 encode the authenticated client username.
7146 TYPE: icap_service_type
7148 LOC: Adaptation::Icap::TheConfig
7151 Defines a single ICAP service using the following format:
7153 icap_service id vectoring_point uri [option ...]
7156 an opaque identifier or name which is used to direct traffic to
7157 this specific service. Must be unique among all adaptation
7158 services in squid.conf.
7160 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7161 This specifies at which point of transaction processing the
7162 ICAP service should be activated. *_postcache vectoring points
7163 are not yet supported.
7165 uri: icap://servername:port/servicepath
7166 ICAP server and service location.
7168 ICAP does not allow a single service to handle both REQMOD and RESPMOD
7169 transactions. Squid does not enforce that requirement. You can specify
7170 services with the same service_url and different vectoring_points. You
7171 can even specify multiple identical services as long as their
7172 service_names differ.
7175 Service options are separated by white space. ICAP services support
7176 the following name=value options:
7179 If set to 'on' or '1', the ICAP service is treated as
7180 optional. If the service cannot be reached or malfunctions,
7181 Squid will try to ignore any errors and process the message as
7182 if the service was not enabled. No all ICAP errors can be
7183 bypassed. If set to 0, the ICAP service is treated as
7184 essential and all ICAP errors will result in an error page
7185 returned to the HTTP client.
7187 Bypass is off by default: services are treated as essential.
7190 If set to 'on' or '1', the ICAP service is allowed to
7191 dynamically change the current message adaptation plan by
7192 returning a chain of services to be used next. The services
7193 are specified using the X-Next-Services ICAP response header
7194 value, formatted as a comma-separated list of service names.
7195 Each named service should be configured in squid.conf. Other
7196 services are ignored. An empty X-Next-Services value results
7197 in an empty plan which ends the current adaptation.
7199 Dynamic adaptation plan may cross or cover multiple supported
7200 vectoring points in their natural processing order.
7202 Routing is not allowed by default: the ICAP X-Next-Services
7203 response header is ignored.
7206 Only has effect on split-stack systems. The default on those systems
7207 is to use IPv4-only connections. When set to 'on' this option will
7208 make Squid use IPv6-only connections to contact this ICAP service.
7210 on-overload=block|bypass|wait|force
7211 If the service Max-Connections limit has been reached, do
7212 one of the following for each new ICAP transaction:
7213 * block: send an HTTP error response to the client
7214 * bypass: ignore the "over-connected" ICAP service
7215 * wait: wait (in a FIFO queue) for an ICAP connection slot
7216 * force: proceed, ignoring the Max-Connections limit
7218 In SMP mode with N workers, each worker assumes the service
7219 connection limit is Max-Connections/N, even though not all
7220 workers may use a given service.
7222 The default value is "bypass" if service is bypassable,
7223 otherwise it is set to "wait".
7227 Use the given number as the Max-Connections limit, regardless
7228 of the Max-Connections value given by the service, if any.
7230 Older icap_service format without optional named parameters is
7231 deprecated but supported for backward compatibility.
7234 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
7235 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
7239 TYPE: icap_class_type
7244 This deprecated option was documented to define an ICAP service
7245 chain, even though it actually defined a set of similar, redundant
7246 services, and the chains were not supported.
7248 To define a set of redundant services, please use the
7249 adaptation_service_set directive. For service chains, use
7250 adaptation_service_chain.
7254 TYPE: icap_access_type
7259 This option is deprecated. Please use adaptation_access, which
7260 has the same ICAP functionality, but comes with better
7261 documentation, and eCAP support.
7266 -----------------------------------------------------------------------------
7273 LOC: Adaptation::Ecap::TheConfig.onoff
7276 Controls whether eCAP support is enabled.
7280 TYPE: ecap_service_type
7282 LOC: Adaptation::Ecap::TheConfig
7285 Defines a single eCAP service
7287 ecap_service id vectoring_point uri [option ...]
7290 an opaque identifier or name which is used to direct traffic to
7291 this specific service. Must be unique among all adaptation
7292 services in squid.conf.
7294 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7295 This specifies at which point of transaction processing the
7296 eCAP service should be activated. *_postcache vectoring points
7297 are not yet supported.
7299 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
7300 Squid uses the eCAP service URI to match this configuration
7301 line with one of the dynamically loaded services. Each loaded
7302 eCAP service must have a unique URI. Obtain the right URI from
7303 the service provider.
7306 Service options are separated by white space. eCAP services support
7307 the following name=value options:
7310 If set to 'on' or '1', the eCAP service is treated as optional.
7311 If the service cannot be reached or malfunctions, Squid will try
7312 to ignore any errors and process the message as if the service
7313 was not enabled. No all eCAP errors can be bypassed.
7314 If set to 'off' or '0', the eCAP service is treated as essential
7315 and all eCAP errors will result in an error page returned to the
7318 Bypass is off by default: services are treated as essential.
7321 If set to 'on' or '1', the eCAP service is allowed to
7322 dynamically change the current message adaptation plan by
7323 returning a chain of services to be used next.
7325 Dynamic adaptation plan may cross or cover multiple supported
7326 vectoring points in their natural processing order.
7328 Routing is not allowed by default.
7330 Older ecap_service format without optional named parameters is
7331 deprecated but supported for backward compatibility.
7335 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
7336 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
7339 NAME: loadable_modules
7341 IFDEF: USE_LOADABLE_MODULES
7342 LOC: Config.loadable_module_names
7345 Instructs Squid to load the specified dynamic module(s) or activate
7346 preloaded module(s).
7348 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
7352 MESSAGE ADAPTATION OPTIONS
7353 -----------------------------------------------------------------------------
7356 NAME: adaptation_service_set
7357 TYPE: adaptation_service_set_type
7358 IFDEF: USE_ADAPTATION
7363 Configures an ordered set of similar, redundant services. This is
7364 useful when hot standby or backup adaptation servers are available.
7366 adaptation_service_set set_name service_name1 service_name2 ...
7368 The named services are used in the set declaration order. The first
7369 applicable adaptation service from the set is used first. The next
7370 applicable service is tried if and only if the transaction with the
7371 previous service fails and the message waiting to be adapted is still
7374 When adaptation starts, broken services are ignored as if they were
7375 not a part of the set. A broken service is a down optional service.
7377 The services in a set must be attached to the same vectoring point
7378 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7380 If all services in a set are optional then adaptation failures are
7381 bypassable. If all services in the set are essential, then a
7382 transaction failure with one service may still be retried using
7383 another service from the set, but when all services fail, the master
7384 transaction fails as well.
7386 A set may contain a mix of optional and essential services, but that
7387 is likely to lead to surprising results because broken services become
7388 ignored (see above), making previously bypassable failures fatal.
7389 Technically, it is the bypassability of the last failed service that
7392 See also: adaptation_access adaptation_service_chain
7395 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
7396 adaptation service_set svcLogger loggerLocal loggerRemote
7399 NAME: adaptation_service_chain
7400 TYPE: adaptation_service_chain_type
7401 IFDEF: USE_ADAPTATION
7406 Configures a list of complementary services that will be applied
7407 one-by-one, forming an adaptation chain or pipeline. This is useful
7408 when Squid must perform different adaptations on the same message.
7410 adaptation_service_chain chain_name service_name1 svc_name2 ...
7412 The named services are used in the chain declaration order. The first
7413 applicable adaptation service from the chain is used first. The next
7414 applicable service is applied to the successful adaptation results of
7415 the previous service in the chain.
7417 When adaptation starts, broken services are ignored as if they were
7418 not a part of the chain. A broken service is a down optional service.
7420 Request satisfaction terminates the adaptation chain because Squid
7421 does not currently allow declaration of RESPMOD services at the
7422 "reqmod_precache" vectoring point (see icap_service or ecap_service).
7424 The services in a chain must be attached to the same vectoring point
7425 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7427 A chain may contain a mix of optional and essential services. If an
7428 essential adaptation fails (or the failure cannot be bypassed for
7429 other reasons), the master transaction fails. Otherwise, the failure
7430 is bypassed as if the failed adaptation service was not in the chain.
7432 See also: adaptation_access adaptation_service_set
7435 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
7438 NAME: adaptation_access
7439 TYPE: adaptation_access_type
7440 IFDEF: USE_ADAPTATION
7444 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
7446 adaptation_access service_name allow|deny [!]aclname...
7447 adaptation_access set_name allow|deny [!]aclname...
7449 At each supported vectoring point, the adaptation_access
7450 statements are processed in the order they appear in this
7451 configuration file. Statements pointing to the following services
7452 are ignored (i.e., skipped without checking their ACL):
7454 - services serving different vectoring points
7455 - "broken-but-bypassable" services
7456 - "up" services configured to ignore such transactions
7457 (e.g., based on the ICAP Transfer-Ignore header).
7459 When a set_name is used, all services in the set are checked
7460 using the same rules, to find the first applicable one. See
7461 adaptation_service_set for details.
7463 If an access list is checked and there is a match, the
7464 processing stops: For an "allow" rule, the corresponding
7465 adaptation service is used for the transaction. For a "deny"
7466 rule, no adaptation service is activated.
7468 It is currently not possible to apply more than one adaptation
7469 service at the same vectoring point to the same HTTP transaction.
7471 See also: icap_service and ecap_service
7474 adaptation_access service_1 allow all
7477 NAME: adaptation_service_iteration_limit
7479 IFDEF: USE_ADAPTATION
7480 LOC: Adaptation::Config::service_iteration_limit
7483 Limits the number of iterations allowed when applying adaptation
7484 services to a message. If your longest adaptation set or chain
7485 may have more than 16 services, increase the limit beyond its
7486 default value of 16. If detecting infinite iteration loops sooner
7487 is critical, make the iteration limit match the actual number
7488 of services in your longest adaptation set or chain.
7490 Infinite adaptation loops are most likely with routing services.
7492 See also: icap_service routing=1
7495 NAME: adaptation_masterx_shared_names
7497 IFDEF: USE_ADAPTATION
7498 LOC: Adaptation::Config::masterx_shared_name
7501 For each master transaction (i.e., the HTTP request and response
7502 sequence, including all related ICAP and eCAP exchanges), Squid
7503 maintains a table of metadata. The table entries are (name, value)
7504 pairs shared among eCAP and ICAP exchanges. The table is destroyed
7505 with the master transaction.
7507 This option specifies the table entry names that Squid must accept
7508 from and forward to the adaptation transactions.
7510 An ICAP REQMOD or RESPMOD transaction may set an entry in the
7511 shared table by returning an ICAP header field with a name
7512 specified in adaptation_masterx_shared_names.
7514 An eCAP REQMOD or RESPMOD transaction may set an entry in the
7515 shared table by implementing the libecap::visitEachOption() API
7516 to provide an option with a name specified in
7517 adaptation_masterx_shared_names.
7519 Squid will store and forward the set entry to subsequent adaptation
7520 transactions within the same master transaction scope.
7522 Only one shared entry name is supported at this time.
7525 # share authentication information among ICAP services
7526 adaptation_masterx_shared_names X-Subscriber-ID
7529 NAME: adaptation_meta
7531 IFDEF: USE_ADAPTATION
7532 LOC: Adaptation::Config::metaHeaders
7535 This option allows Squid administrator to add custom ICAP request
7536 headers or eCAP options to Squid ICAP requests or eCAP transactions.
7537 Use it to pass custom authentication tokens and other
7538 transaction-state related meta information to an ICAP/eCAP service.
7540 The addition of a meta header is ACL-driven:
7541 adaptation_meta name value [!]aclname ...
7543 Processing for a given header name stops after the first ACL list match.
7544 Thus, it is impossible to add two headers with the same name. If no ACL
7545 lists match for a given header name, no such header is added. For
7548 # do not debug transactions except for those that need debugging
7549 adaptation_meta X-Debug 1 needs_debugging
7551 # log all transactions except for those that must remain secret
7552 adaptation_meta X-Log 1 !keep_secret
7554 # mark transactions from users in the "G 1" group
7555 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
7557 The "value" parameter may be a regular squid.conf token or a "double
7558 quoted string". Within the quoted string, use backslash (\) to escape
7559 any character, which is currently only useful for escaping backslashes
7560 and double quotes. For example,
7561 "this string has one backslash (\\) and two \"quotes\""
7563 Used adaptation_meta header values may be logged via %note
7564 logformat code. If multiple adaptation_meta headers with the same name
7565 are used during master transaction lifetime, the header values are
7566 logged in the order they were used and duplicate values are ignored
7567 (only the first repeated value will be logged).
7573 LOC: Adaptation::Icap::TheConfig.repeat
7574 DEFAULT_IF_NONE: deny all
7576 This ACL determines which retriable ICAP transactions are
7577 retried. Transactions that received a complete ICAP response
7578 and did not have to consume or produce HTTP bodies to receive
7579 that response are usually retriable.
7581 icap_retry allow|deny [!]aclname ...
7583 Squid automatically retries some ICAP I/O timeouts and errors
7584 due to persistent connection race conditions.
7586 See also: icap_retry_limit
7589 NAME: icap_retry_limit
7592 LOC: Adaptation::Icap::TheConfig.repeat_limit
7595 Limits the number of retries allowed. When set to zero (default),
7596 no retries are allowed.
7598 Communication errors due to persistent connection race
7599 conditions are unavoidable, automatically retried, and do not
7600 count against this limit.
7602 See also: icap_retry
7608 -----------------------------------------------------------------------------
7611 NAME: check_hostnames
7614 LOC: Config.onoff.check_hostnames
7616 For security and stability reasons Squid can check
7617 hostnames for Internet standard RFC compliance. If you want
7618 Squid to perform these checks turn this directive on.
7621 NAME: allow_underscore
7624 LOC: Config.onoff.allow_underscore
7626 Underscore characters is not strictly allowed in Internet hostnames
7627 but nevertheless used by many sites. Set this to off if you want
7628 Squid to be strict about the standard.
7629 This check is performed only when check_hostnames is set to on.
7632 NAME: cache_dns_program
7634 IFDEF: USE_DNSHELPER
7635 DEFAULT: @DEFAULT_DNSSERVER@
7636 LOC: Config.Program.dnsserver
7638 Specify the location of the executable for dnslookup process.
7642 TYPE: HelperChildConfig
7643 IFDEF: USE_DNSHELPER
7644 DEFAULT: 32 startup=1 idle=1
7645 LOC: Config.dnsChildren
7647 The maximum number of processes spawn to service DNS name lookups.
7648 If you limit it too few Squid will have to wait for them to process
7649 a backlog of requests, slowing it down. If you allow too many they
7650 will use RAM and other system resources noticably.
7651 The maximum this may be safely set to is 32.
7653 The startup= and idle= options allow some measure of skew in your
7658 Sets a minimum of how many processes are to be spawned when Squid
7659 starts or reconfigures. When set to zero the first request will
7660 cause spawning of the first child process to handle it.
7662 Starting too few will cause an initial slowdown in traffic as Squid
7663 attempts to simultaneously spawn enough processes to cope.
7667 Sets a minimum of how many processes Squid is to try and keep available
7668 at all times. When traffic begins to rise above what the existing
7669 processes can handle this many more will be spawned up to the maximum
7670 configured. A minimum setting of 1 is required.
7673 NAME: dns_retransmit_interval
7676 LOC: Config.Timeout.idns_retransmit
7677 IFDEF: !USE_DNSHELPER
7679 Initial retransmit interval for DNS queries. The interval is
7680 doubled each time all configured DNS servers have been tried.
7686 LOC: Config.Timeout.idns_query
7687 IFDEF: !USE_DNSHELPER
7689 DNS Query timeout. If no response is received to a DNS query
7690 within this time all DNS servers for the queried domain
7691 are assumed to be unavailable.
7694 NAME: dns_packet_max
7697 LOC: Config.dns.packet_max
7698 IFDEF: !USE_DNSHELPER
7700 Maximum number of bytes packet size to advertise via EDNS.
7701 Set to "none" to disable EDNS large packet support.
7703 For legacy reasons DNS UDP replies will default to 512 bytes which
7704 is too small for many responses. EDNS provides a means for Squid to
7705 negotiate receiving larger responses back immediately without having
7706 to failover with repeat requests. Responses larger than this limit
7707 will retain the old behaviour of failover to TCP DNS.
7709 Squid has no real fixed limit internally, but allowing packet sizes
7710 over 1500 bytes requires network jumbogram support and is usually not
7713 WARNING: The RFC also indicates that some older resolvers will reply
7714 with failure of the whole request if the extension is added. Some
7715 resolvers have already been identified which will reply with mangled
7716 EDNS response on occasion. Usually in response to many-KB jumbogram
7717 sizes being advertised by Squid.
7718 Squid will currently treat these both as an unable-to-resolve domain
7719 even if it would be resolvable without EDNS.
7726 LOC: Config.onoff.res_defnames
7728 Normally the RES_DEFNAMES resolver option is disabled
7729 (see res_init(3)). This prevents caches in a hierarchy
7730 from interpreting single-component hostnames locally. To allow
7731 Squid to handle single-component names, enable this option.
7734 NAME: dns_nameservers
7737 LOC: Config.dns_nameservers
7739 Use this if you want to specify a list of DNS name servers
7740 (IP addresses) to use instead of those given in your
7741 /etc/resolv.conf file.
7742 On Windows platforms, if no value is specified here or in
7743 the /etc/resolv.conf file, the list of DNS name servers are
7744 taken from the Windows registry, both static and dynamic DHCP
7745 configurations are supported.
7747 Example: dns_nameservers 10.0.0.1 192.172.0.4
7752 DEFAULT: @DEFAULT_HOSTS@
7753 LOC: Config.etcHostsPath
7755 Location of the host-local IP name-address associations
7756 database. Most Operating Systems have such a file on different
7758 - Un*X & Linux: /etc/hosts
7759 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
7760 (%SystemRoot% value install default is c:\winnt)
7761 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
7762 (%SystemRoot% value install default is c:\windows)
7763 - Windows 9x/Me: %windir%\hosts
7764 (%windir% value is usually c:\windows)
7765 - Cygwin: /etc/hosts
7767 The file contains newline-separated definitions, in the
7768 form ip_address_in_dotted_form name [name ...] names are
7769 whitespace-separated. Lines beginning with an hash (#)
7770 character are comments.
7772 The file is checked at startup and upon configuration.
7773 If set to 'none', it won't be checked.
7774 If append_domain is used, that domain will be added to
7775 domain-local (i.e. not containing any dot character) host
7781 LOC: Config.appendDomain
7784 Appends local domain name to hostnames without any dots in
7785 them. append_domain must begin with a period.
7787 Be warned there are now Internet names with no dots in
7788 them using only top-domain names, so setting this may
7789 cause some Internet sites to become unavailable.
7792 append_domain .yourdomain.com
7795 NAME: ignore_unknown_nameservers
7797 LOC: Config.onoff.ignore_unknown_nameservers
7799 IFDEF: !USE_DNSHELPER
7801 By default Squid checks that DNS responses are received
7802 from the same IP addresses they are sent to. If they
7803 don't match, Squid ignores the response and writes a warning
7804 message to cache.log. You can allow responses from unknown
7805 nameservers by setting this option to 'off'.
7811 LOC: Config.dns.v4_first
7812 IFDEF: !USE_DNSHELPER
7814 With the IPv6 Internet being as fast or faster than IPv4 Internet
7815 for most networks Squid prefers to contact websites over IPv6.
7817 This option reverses the order of preference to make Squid contact
7818 dual-stack websites over IPv4 first. Squid will still perform both
7819 IPv6 and IPv4 DNS lookups before connecting.
7822 This option will restrict the situations under which IPv6
7823 connectivity is used (and tested). Hiding network problems
7824 which would otherwise be detected and warned about.
7828 COMMENT: (number of entries)
7831 LOC: Config.ipcache.size
7838 LOC: Config.ipcache.low
7845 LOC: Config.ipcache.high
7847 The size, low-, and high-water marks for the IP cache.
7850 NAME: fqdncache_size
7851 COMMENT: (number of entries)
7854 LOC: Config.fqdncache.size
7856 Maximum number of FQDN cache entries.
7861 -----------------------------------------------------------------------------
7868 LOC: Config.onoff.mem_pools
7870 If set, Squid will keep pools of allocated (but unused) memory
7871 available for future use. If memory is a premium on your
7872 system and you believe your malloc library outperforms Squid
7873 routines, disable this.
7876 NAME: memory_pools_limit
7880 LOC: Config.MemPools.limit
7882 Used only with memory_pools on:
7883 memory_pools_limit 50 MB
7885 If set to a non-zero value, Squid will keep at most the specified
7886 limit of allocated (but unused) memory in memory pools. All free()
7887 requests that exceed this limit will be handled by your malloc
7888 library. Squid does not pre-allocate any memory, just safe-keeps
7889 objects that otherwise would be free()d. Thus, it is safe to set
7890 memory_pools_limit to a reasonably high value even if your
7891 configuration will use less memory.
7893 If set to none, Squid will keep all memory it can. That is, there
7894 will be no limit on the total amount of memory used for safe-keeping.
7896 To disable memory allocation optimization, do not set
7897 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
7899 An overhead for maintaining memory pools is not taken into account
7900 when the limit is checked. This overhead is close to four bytes per
7901 object kept. However, pools may actually _save_ memory because of
7902 reduced memory thrashing in your malloc library.
7906 COMMENT: on|off|transparent|truncate|delete
7909 LOC: opt_forwarded_for
7911 If set to "on", Squid will append your client's IP address
7912 in the HTTP requests it forwards. By default it looks like:
7914 X-Forwarded-For: 192.1.2.3
7916 If set to "off", it will appear as
7918 X-Forwarded-For: unknown
7920 If set to "transparent", Squid will not alter the
7921 X-Forwarded-For header in any way.
7923 If set to "delete", Squid will delete the entire
7924 X-Forwarded-For header.
7926 If set to "truncate", Squid will remove all existing
7927 X-Forwarded-For entries, and place the client IP as the sole entry.
7930 NAME: cachemgr_passwd
7931 TYPE: cachemgrpasswd
7933 LOC: Config.passwd_list
7935 Specify passwords for cachemgr operations.
7937 Usage: cachemgr_passwd password action action ...
7939 Some valid actions are (see cache manager menu for a full list):
7979 * Indicates actions which will not be performed without a
7980 valid password, others can be performed if not listed here.
7982 To disable an action, set the password to "disable".
7983 To allow performing an action without a password, set the
7986 Use the keyword "all" to set the same password for all actions.
7989 cachemgr_passwd secret shutdown
7990 cachemgr_passwd lesssssssecret info stats/objects
7991 cachemgr_passwd disable all
7998 LOC: Config.onoff.client_db
8000 If you want to disable collecting per-client statistics,
8001 turn off client_db here.
8004 NAME: refresh_all_ims
8008 LOC: Config.onoff.refresh_all_ims
8010 When you enable this option, squid will always check
8011 the origin server for an update when a client sends an
8012 If-Modified-Since request. Many browsers use IMS
8013 requests when the user requests a reload, and this
8014 ensures those clients receive the latest version.
8016 By default (off), squid may return a Not Modified response
8017 based on the age of the cached version.
8020 NAME: reload_into_ims
8021 IFDEF: USE_HTTP_VIOLATIONS
8025 LOC: Config.onoff.reload_into_ims
8027 When you enable this option, client no-cache or ``reload''
8028 requests will be changed to If-Modified-Since requests.
8029 Doing this VIOLATES the HTTP standard. Enabling this
8030 feature could make you liable for problems which it
8033 see also refresh_pattern for a more selective approach.
8036 NAME: connect_retries
8038 LOC: Config.connect_retries
8041 This sets the maximum number of connection attempts made for each
8042 TCP connection. The connect_retries attempts must all still
8043 complete within the connection timeout period.
8045 The default is not to re-try if the first connection attempt fails.
8046 The (not recommended) maximum is 10 tries.
8048 A warning message will be generated if it is set to a too-high
8049 value and the configured value will be over-ridden.
8051 Note: These re-tries are in addition to forward_max_tries
8052 which limit how many different addresses may be tried to find
8056 NAME: retry_on_error
8058 LOC: Config.retry.onerror
8061 If set to ON Squid will automatically retry requests when
8062 receiving an error response with status 403 (Forbidden),
8063 500 (Internal Error), 501 or 503 (Service not available).
8064 Status 502 and 504 (Gateway errors) are always retried.
8066 This is mainly useful if you are in a complex cache hierarchy to
8067 work around access control errors.
8069 NOTE: This retry will attempt to find another working destination.
8070 Which is different from the server which just failed.
8073 NAME: as_whois_server
8075 LOC: Config.as_whois_server
8076 DEFAULT: whois.ra.net
8078 WHOIS server to query for AS numbers. NOTE: AS numbers are
8079 queried only when Squid starts up, not for every request.
8084 LOC: Config.onoff.offline
8087 Enable this option and Squid will never try to validate cached
8091 NAME: uri_whitespace
8092 TYPE: uri_whitespace
8093 LOC: Config.uri_whitespace
8096 What to do with requests that have whitespace characters in the
8099 strip: The whitespace characters are stripped out of the URL.
8100 This is the behavior recommended by RFC2396.
8101 deny: The request is denied. The user receives an "Invalid
8103 allow: The request is allowed and the URI is not changed. The
8104 whitespace characters remain in the URI. Note the
8105 whitespace is passed to redirector processes if they
8107 encode: The request is allowed and the whitespace characters are
8108 encoded according to RFC1738. This could be considered
8109 a violation of the HTTP/1.1
8110 RFC because proxies are not allowed to rewrite URI's.
8111 chop: The request is allowed and the URI is chopped at the
8112 first whitespace. This might also be considered a
8118 LOC: Config.chroot_dir
8121 Specifies a directory where Squid should do a chroot() while
8122 initializing. This also causes Squid to fully drop root
8123 privileges after initializing. This means, for example, if you
8124 use a HTTP port less than 1024 and try to reconfigure, you may
8125 get an error saying that Squid can not open the port.
8128 NAME: balance_on_multiple_ip
8130 LOC: Config.onoff.balance_on_multiple_ip
8133 Modern IP resolvers in squid sort lookup results by preferred access.
8134 By default squid will use these IP in order and only rotates to
8135 the next listed when the most preffered fails.
8137 Some load balancing servers based on round robin DNS have been
8138 found not to preserve user session state across requests
8139 to different IP addresses.
8141 Enabling this directive Squid rotates IP's per request.
8144 NAME: pipeline_prefetch
8146 LOC: Config.onoff.pipeline_prefetch
8149 To boost the performance of pipelined requests to closer
8150 match that of a non-proxied environment Squid can try to fetch
8151 up to two requests in parallel from a pipeline.
8153 Defaults to off for bandwidth management and access logging
8156 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
8159 NAME: high_response_time_warning
8162 LOC: Config.warnings.high_rptm
8165 If the one-minute median response time exceeds this value,
8166 Squid prints a WARNING with debug level 0 to get the
8167 administrators attention. The value is in milliseconds.
8170 NAME: high_page_fault_warning
8172 LOC: Config.warnings.high_pf
8175 If the one-minute average page fault rate exceeds this
8176 value, Squid prints a WARNING with debug level 0 to get
8177 the administrators attention. The value is in page faults
8181 NAME: high_memory_warning
8183 LOC: Config.warnings.high_memory
8186 If the memory usage (as determined by mallinfo) exceeds
8187 this amount, Squid prints a WARNING with debug level 0 to get
8188 the administrators attention.
8191 NAME: sleep_after_fork
8192 COMMENT: (microseconds)
8194 LOC: Config.sleep_after_fork
8197 When this is set to a non-zero value, the main Squid process
8198 sleeps the specified number of microseconds after a fork()
8199 system call. This sleep may help the situation where your
8200 system reports fork() failures due to lack of (virtual)
8201 memory. Note, however, if you have a lot of child
8202 processes, these sleep delays will add up and your
8203 Squid will not service requests for some amount of time
8204 until all the child processes have been started.
8205 On Windows value less then 1000 (1 milliseconds) are
8209 NAME: windows_ipaddrchangemonitor
8210 IFDEF: _SQUID_WINDOWS_
8214 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
8216 On Windows Squid by default will monitor IP address changes and will
8217 reconfigure itself after any detected event. This is very useful for
8218 proxies connected to internet with dial-up interfaces.
8219 In some cases (a Proxy server acting as VPN gateway is one) it could be
8220 desiderable to disable this behaviour setting this to 'off'.
8221 Note: after changing this, Squid service must be restarted.
8226 IFDEF: USE_SQUID_EUI
8228 LOC: Eui::TheConfig.euiLookup
8230 Whether to lookup the EUI or MAC address of a connected client.
8233 NAME: max_filedescriptors max_filedesc
8236 LOC: Config.max_filedescriptors
8238 The maximum number of filedescriptors supported.
8240 The default "0" means Squid inherits the current ulimit setting.
8242 Note: Changing this requires a restart of Squid. Also
8243 not all comm loops supports large values.
8251 Number of main Squid processes or "workers" to fork and maintain.
8252 0: "no daemon" mode, like running "squid -N ..."
8253 1: "no SMP" mode, start one main Squid process daemon (default)
8254 N: start N main Squid process daemons (i.e., SMP mode)
8256 In SMP mode, each worker does nearly all what a single Squid daemon
8257 does (e.g., listen on http_port and forward HTTP requests).
8260 NAME: cpu_affinity_map
8261 TYPE: CpuAffinityMap
8262 LOC: Config.cpuAffinityMap
8265 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
8267 Sets 1:1 mapping between Squid processes and CPU cores. For example,
8269 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
8271 affects processes 1 through 4 only and places them on the first
8272 four even cores, starting with core #1.
8274 CPU cores are numbered starting from 1. Requires support for
8275 sched_getaffinity(2) and sched_setaffinity(2) system calls.
8277 Multiple cpu_affinity_map options are merged.