3 # $Id: cf.data.pre,v 1.489 2007/12/14 23:11:46 amosjeffries Exp $
5 # SQUID Web Proxy Cache http://www.squid-cache.org/
6 # ----------------------------------------------------------
8 # Squid is the result of efforts by numerous individuals from
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14 # incorporates software developed and/or copyrighted by other
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17 # This program is free software; you can redistribute it and/or modify
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20 # (at your option) any later version.
22 # This program is distributed in the hope that it will be useful,
23 # but WITHOUT ANY WARRANTY; without even the implied warranty of
24 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 # GNU General Public License for more details.
27 # You should have received a copy of the GNU General Public License
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29 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
33 WELCOME TO SQUID @VERSION@
34 ----------------------------
36 This is the default Squid configuration file. You may wish
37 to look at the Squid home page (http://www.squid-cache.org/)
38 for the FAQ and other documentation.
40 The default Squid config file shows what the defaults for
41 various options happen to be. If you don't need to change the
42 default, you shouldn't uncomment the line. Doing so may cause
43 run-time problems. In some cases "none" refers to no default
44 setting at all, while in other cases it refers to a valid
45 option - the comments for that keyword indicate if this is the
51 OPTIONS FOR AUTHENTICATION
52 -----------------------------------------------------------------------------
57 LOC: Config.authConfiguration
60 This is used to define parameters for the various authentication
61 schemes supported by Squid.
63 format: auth_param scheme parameter [setting]
65 The order in which authentication schemes are presented to the client is
66 dependent on the order the scheme first appears in config file. IE
67 has a bug (it's not RFC 2617 compliant) in that it will use the basic
68 scheme if basic is the first entry presented, even if more secure
69 schemes are presented. For now use the order in the recommended
70 settings section below. If other browsers have difficulties (don't
71 recognize the schemes offered even if you are using basic) either
72 put basic first, or disable the other schemes (by commenting out their
75 Once an authentication scheme is fully configured, it can only be
76 shutdown by shutting squid down and restarting. Changes can be made on
77 the fly and activated with a reconfigure. I.E. You can change to a
78 different helper, but not unconfigure the helper completely.
80 Please note that while this directive defines how Squid processes
81 authentication it does not automatically activate authentication.
82 To use authentication you must in addition make use of ACLs based
83 on login name in http_access (proxy_auth, proxy_auth_regex or
84 external with %LOGIN used in the format tag). The browser will be
85 challenged for authentication on the first such acl encountered
86 in http_access processing and will also be re-challenged for new
87 login credentials if the request is being denied by a proxy_auth
90 WARNING: authentication can't be used in a transparently intercepting
91 proxy as the client then thinks it is talking to an origin server and
92 not the proxy. This is a limitation of bending the TCP/IP protocol to
93 transparently intercepting port 80, not a limitation in Squid.
95 === Parameters for the basic scheme follow. ===
98 Specify the command for the external authenticator. Such a program
99 reads a line containing "username password" and replies "OK" or
100 "ERR" in an endless loop. "ERR" responses may optionally be followed
101 by a error description available as %m in the returned error page.
102 If you use an authenticator, make sure you have 1 acl of type proxy_auth.
104 By default, the basic authentication scheme is not used unless a
105 program is specified.
107 If you want to use the traditional NCSA proxy authentication, set
108 this line to something like
110 auth_param basic program @DEFAULT_PREFIX@/libexec/ncsa_auth @DEFAULT_PREFIX@/etc/passwd
112 "children" numberofchildren
113 The number of authenticator processes to spawn. If you start too few
114 Squid will have to wait for them to process a backlog of credential
115 verifications, slowing it down. When password verifications are
116 done via a (slow) network you are likely to need lots of
117 authenticator processes.
118 auth_param basic children 5
120 "concurrency" concurrency
121 The number of concurrent requests the helper can process.
122 The default of 0 is used for helpers who only supports
123 one request at a time. Setting this changes the protocol used to
124 include a channel number first on the request/response line, allowing
125 multiple requests to be sent to the same helper in parallell without
126 wating for the response.
127 Must not be set unless it's known the helper supports this.
128 auth_param basic concurrency 0
131 Specifies the realm name which is to be reported to the
132 client for the basic proxy authentication scheme (part of
133 the text the user will see when prompted their username and
134 password). There is no default.
135 auth_param basic realm Squid proxy-caching web server
137 "credentialsttl" timetolive
138 Specifies how long squid assumes an externally validated
139 username:password pair is valid for - in other words how
140 often the helper program is called for that user. Set this
141 low to force revalidation with short lived passwords. Note
142 setting this high does not impact your susceptibility
143 to replay attacks unless you are using an one-time password
144 system (such as SecureID). If you are using such a system,
145 you will be vulnerable to replay attacks unless you also
146 use the max_user_ip ACL in an http_access rule.
148 "casesensitive" on|off
149 Specifies if usernames are case sensitive. Most user databases are
150 case insensitive allowing the same username to be spelled using both
151 lower and upper case letters, but some are case sensitive. This
152 makes a big difference for user_max_ip ACL processing and similar.
153 auth_param basic casesensitive off
155 === Parameters for the digest scheme follow ===
158 Specify the command for the external authenticator. Such
159 a program reads a line containing "username":"realm" and
160 replies with the appropriate H(A1) value hex encoded or
161 ERR if the user (or his H(A1) hash) does not exists.
162 See rfc 2616 for the definition of H(A1).
163 "ERR" responses may optionally be followed by a error description
164 available as %m in the returned error page.
166 By default, the digest authentication scheme is not used unless a
167 program is specified.
169 If you want to use a digest authenticator, set this line to
172 auth_param digest program @DEFAULT_PREFIX@/bin/digest_auth_pw @DEFAULT_PREFIX@/etc/digpass
174 "children" numberofchildren
175 The number of authenticator processes to spawn (no default).
176 If you start too few Squid will have to wait for them to
177 process a backlog of H(A1) calculations, slowing it down.
178 When the H(A1) calculations are done via a (slow) network
179 you are likely to need lots of authenticator processes.
180 auth_param digest children 5
183 Specifies the realm name which is to be reported to the
184 client for the digest proxy authentication scheme (part of
185 the text the user will see when prompted their username and
186 password). There is no default.
187 auth_param digest realm Squid proxy-caching web server
189 "nonce_garbage_interval" timeinterval
190 Specifies the interval that nonces that have been issued
191 to client_agent's are checked for validity.
193 "nonce_max_duration" timeinterval
194 Specifies the maximum length of time a given nonce will be
197 "nonce_max_count" number
198 Specifies the maximum number of times a given nonce can be
201 "nonce_strictness" on|off
202 Determines if squid requires strict increment-by-1 behavior
203 for nonce counts, or just incrementing (off - for use when
204 useragents generate nonce counts that occasionally miss 1
205 (ie, 1,2,4,6)). Default off.
207 "check_nonce_count" on|off
208 This directive if set to off can disable the nonce count check
209 completely to work around buggy digest qop implementations in
210 certain mainstream browser versions. Default on to check the
211 nonce count to protect from authentication replay attacks.
213 "post_workaround" on|off
214 This is a workaround to certain buggy browsers who sends
215 an incorrect request digest in POST requests when reusing
216 the same nonce as acquired earlier on a GET request.
218 === NTLM scheme options follow ===
221 Specify the command for the external NTLM authenticator.
222 Such a program reads exchanged NTLMSSP packets with
223 the browser via Squid until authentication is completed.
224 If you use an NTLM authenticator, make sure you have 1 acl
225 of type proxy_auth. By default, the NTLM authenticator_program
228 auth_param ntlm program @DEFAULT_PREFIX@/bin/ntlm_auth
230 "children" numberofchildren
231 The number of authenticator processes to spawn (no default).
232 If you start too few Squid will have to wait for them to
233 process a backlog of credential verifications, slowing it
234 down. When credential verifications are done via a (slow)
235 network you are likely to need lots of authenticator
238 auth_param ntlm children 5
241 If you experience problems with PUT/POST requests when using the
242 Negotiate authentication scheme then you can try setting this to
243 off. This will cause Squid to forcibly close the connection on
244 the initial requests where the browser asks which schemes are
245 supported by the proxy.
247 auth_param ntlm keep_alive on
249 === Options for configuring the NEGOTIATE auth-scheme follow ===
252 Specify the command for the external Negotiate authenticator.
253 This protocol is used in Microsoft Active-Directory enabled setups with
254 the Microsoft Internet Explorer or Mozilla Firefox browsers.
255 Its main purpose is to exchange credentials with the Squid proxy
256 using the Kerberos mechanisms.
257 If you use a Negotiate authenticator, make sure you have at least one acl
258 of type proxy_auth active. By default, the negotiate authenticator_program
260 The only supported program for this role is the ntlm_auth
261 program distributed as part of Samba, version 4 or later.
263 auth_param negotiate program @DEFAULT_PREFIX@/bin/ntlm_auth --helper-protocol=gss-spnego
265 "children" numberofchildren
266 The number of authenticator processes to spawn (no default).
267 If you start too few Squid will have to wait for them to
268 process a backlog of credential verifications, slowing it
269 down. When crendential verifications are done via a (slow)
270 network you are likely to need lots of authenticator
272 auth_param negotiate children 5
275 If you experience problems with PUT/POST requests when using the
276 Negotiate authentication scheme then you can try setting this to
277 off. This will cause Squid to forcibly close the connection on
278 the initial requests where the browser asks which schemes are
279 supported by the proxy.
281 auth_param negotiate keep_alive on
284 #Recommended minimum configuration per scheme:
285 #auth_param negotiate program <uncomment and complete this line to activate>
286 #auth_param negotiate children 5
287 #auth_param negotiate keep_alive on
288 #auth_param ntlm program <uncomment and complete this line to activate>
289 #auth_param ntlm children 5
290 #auth_param ntlm keep_alive on
291 #auth_param digest program <uncomment and complete this line>
292 #auth_param digest children 5
293 #auth_param digest realm Squid proxy-caching web server
294 #auth_param digest nonce_garbage_interval 5 minutes
295 #auth_param digest nonce_max_duration 30 minutes
296 #auth_param digest nonce_max_count 50
297 #auth_param basic program <uncomment and complete this line>
298 #auth_param basic children 5
299 #auth_param basic realm Squid proxy-caching web server
300 #auth_param basic credentialsttl 2 hours
304 NAME: authenticate_cache_garbage_interval
307 LOC: Config.authenticateGCInterval
309 The time period between garbage collection across the username cache.
310 This is a tradeoff between memory utilization (long intervals - say
311 2 days) and CPU (short intervals - say 1 minute). Only change if you
315 NAME: authenticate_ttl
318 LOC: Config.authenticateTTL
320 The time a user & their credentials stay in the logged in
321 user cache since their last request. When the garbage
322 interval passes, all user credentials that have passed their
323 TTL are removed from memory.
326 NAME: authenticate_ip_ttl
328 LOC: Config.authenticateIpTTL
331 If you use proxy authentication and the 'max_user_ip' ACL,
332 this directive controls how long Squid remembers the IP
333 addresses associated with each user. Use a small value
334 (e.g., 60 seconds) if your users might change addresses
335 quickly, as is the case with dialups. You might be safe
336 using a larger value (e.g., 2 hours) in a corporate LAN
337 environment with relatively static address assignments.
342 -----------------------------------------------------------------------------
345 NAME: external_acl_type
346 TYPE: externalAclHelper
347 LOC: Config.externalAclHelperList
350 This option defines external acl classes using a helper program
351 to look up the status
353 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
357 ttl=n TTL in seconds for cached results (defaults to 3600
360 TTL for cached negative lookups (default same
362 children=n Number of acl helper processes spawn to service
363 external acl lookups of this type. (default 5)
364 concurrency=n concurrency level per process. Only used with helpers
365 capable of processing more than one query at a time.
366 cache=n result cache size, 0 is unbounded (default)
367 grace=n Percentage remaining of TTL where a refresh of a
368 cached entry should be initiated without needing to
369 wait for a new reply. (default 0 for no grace period)
370 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
371 ipv4 / ipv6 IP-mode used to communicate to this helper.
372 For compatability with older configurations and helpers
373 'ipv4' is the default unless --with-localhost-ipv6 is used.
374 --with-localhost-ipv6 changes the default to 'ipv6'.
375 SPECIAL NOTE: these options override --with-localhost-ipv6
377 FORMAT specifications
379 %LOGIN Authenticated user login name
380 %EXT_USER Username from external acl
381 %IDENT Ident user name
383 %SRCPORT Client source port
386 %PROTO Requested protocol
388 %PATH Requested URL path
389 %METHOD Request method
390 %MYADDR Squid interface address
391 %MYPORT Squid http_port number
392 %PATH Requested URL-path (including query-string if any)
393 %USER_CERT SSL User certificate in PEM format
394 %USER_CERTCHAIN SSL User certificate chain in PEM format
395 %USER_CERT_xx SSL User certificate subject attribute xx
396 %USER_CA_xx SSL User certificate issuer attribute xx
397 %{Header} HTTP request header
398 %{Hdr:member} HTTP request header list member
400 HTTP request header list member using ; as
401 list separator. ; can be any non-alphanumeric
404 In addition to the above, any string specified in the referencing
405 acl will also be included in the helper request line, after the
406 specified formats (see the "acl external" directive)
408 The helper receives lines per the above format specification,
409 and returns lines starting with OK or ERR indicating the validity
410 of the request and optionally followed by additional keywords with
413 General result syntax:
415 OK/ERR keyword=value ...
419 user= The users name (login)
420 password= The users password (for login= cache_peer option)
421 message= Message describing the reason. Available as %o
423 tag= Apply a tag to a request (for both ERR and OK results)
424 Only sets a tag, does not alter existing tags.
425 log= String to be logged in access.log. Available as
426 %ea in logformat specifications
428 If protocol=3.0 (the default) then URL escaping is used to protect
429 each value in both requests and responses.
431 If using protocol=2.5 then all values need to be enclosed in quotes
432 if they may contain whitespace, or the whitespace escaped using \.
433 And quotes or \ characters within the keyword value must be \ escaped.
435 When using the concurrency= option the protocol is changed by
436 introducing a query channel tag infront of the request/response.
437 The query channel tag is a number between 0 and concurrency-1.
445 Defining an Access List
447 acl aclname acltype string1 ...
448 acl aclname acltype "file" ...
450 when using "file", the file should contain one item per line
452 acltype is one of the types described below
454 By default, regular expressions are CASE-SENSITIVE. To make
455 them case-insensitive, use the -i option.
457 acl aclname src ip-address/netmask ... (clients IP address)
458 acl aclname src addr1-addr2/netmask ... (range of addresses)
459 acl aclname dst ip-address/netmask ... (URL host's IP address)
460 acl aclname myip ip-address/netmask ... (local socket IP address)
462 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
463 # The arp ACL requires the special configure option --enable-arp-acl.
464 # Furthermore, the ARP ACL code is not portable to all operating systems.
465 # It works on Linux, Solaris, Windows, FreeBSD, and some other *BSD variants.
467 # NOTE: Squid can only determine the MAC address for clients that are on
468 # the same subnet. If the client is on a different subnet, then Squid cannot
469 # find out its MAC address.
471 acl aclname srcdomain .foo.com ... # reverse lookup, client IP
472 acl aclname dstdomain .foo.com ... # Destination server from URL
473 acl aclname srcdom_regex [-i] xxx ... # regex matching client name
474 acl aclname dstdom_regex [-i] xxx ... # regex matching server
475 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
476 # based URL is used and no match is found. The name "none" is used
477 # if the reverse lookup fails.
479 acl aclname http_status 200 301 500- 400-403 ... # status code in reply
481 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
490 h1:m1 must be less than h2:m2
491 acl aclname url_regex [-i] ^http:// ... # regex matching on whole URL
492 acl aclname urlpath_regex [-i] \.gif$ ... # regex matching on URL path
493 acl aclname port 80 70 21 ...
494 acl aclname port 0-1024 ... # ranges allowed
495 acl aclname myport 3128 ... # (local socket TCP port)
496 acl aclname proto HTTP FTP ...
497 acl aclname method GET POST ...
498 acl aclname browser [-i] regexp ...
499 # pattern match on User-Agent header (see also req_header below)
500 acl aclname referer_regex [-i] regexp ...
501 # pattern match on Referer header
502 # Referer is highly unreliable, so use with care
503 acl aclname ident username ...
504 acl aclname ident_regex [-i] pattern ...
505 # string match on ident output.
506 # use REQUIRED to accept any non-null ident.
507 acl aclname src_as number ...
508 acl aclname dst_as number ...
509 # Except for access control, AS numbers can be used for
510 # routing of requests to specific caches. Here's an
511 # example for routing all requests for AS#1241 and only
512 # those to mycache.mydomain.net:
513 # acl asexample dst_as 1241
514 # cache_peer_access mycache.mydomain.net allow asexample
515 # cache_peer_access mycache_mydomain.net deny all
517 acl aclname proxy_auth [-i] username ...
518 acl aclname proxy_auth_regex [-i] pattern ...
519 # list of valid usernames
520 # use REQUIRED to accept any valid username.
522 # NOTE: when a Proxy-Authentication header is sent but it is not
523 # needed during ACL checking the username is NOT logged
526 # NOTE: proxy_auth requires a EXTERNAL authentication program
527 # to check username/password combinations (see
528 # auth_param directive).
530 # NOTE: proxy_auth can't be used in a transparent proxy as
531 # the browser needs to be configured for using a proxy in order
532 # to respond to proxy authentication.
534 acl aclname snmp_community string ...
535 # A community string to limit access to your SNMP Agent
538 # acl snmppublic snmp_community public
540 acl aclname maxconn number
541 # This will be matched when the client's IP address has
542 # more than <number> HTTP connections established.
544 acl aclname max_user_ip [-s] number
545 # This will be matched when the user attempts to log in from more
546 # than <number> different ip addresses. The authenticate_ip_ttl
547 # parameter controls the timeout on the ip entries.
548 # If -s is specified the limit is strict, denying browsing
549 # from any further IP addresses until the ttl has expired. Without
550 # -s Squid will just annoy the user by "randomly" denying requests.
551 # (the counter is reset each time the limit is reached and a
553 # NOTE: in acceleration mode or where there is mesh of child proxies,
554 # clients may appear to come from multiple addresses if they are
555 # going through proxy farms, so a limit of 1 may cause user problems.
557 acl aclname req_mime_type mime-type1 ...
558 # regex match against the mime type of the request generated
559 # by the client. Can be used to detect file upload or some
560 # types HTTP tunneling requests.
561 # NOTE: This does NOT match the reply. You cannot use this
562 # to match the returned file type.
564 acl aclname req_header header-name [-i] any\.regex\.here
565 # regex match against any of the known request headers. May be
566 # thought of as a superset of "browser", "referer" and "mime-type"
569 acl aclname rep_mime_type mime-type1 ...
570 # regex match against the mime type of the reply received by
571 # squid. Can be used to detect file download or some
572 # types HTTP tunneling requests.
573 # NOTE: This has no effect in http_access rules. It only has
574 # effect in rules that affect the reply data stream such as
577 acl aclname rep_header header-name [-i] any\.regex\.here
578 # regex match against any of the known reply headers. May be
579 # thought of as a superset of "browser", "referer" and "mime-type"
582 acl acl_name external class_name [arguments...]
583 # external ACL lookup via a helper class defined by the
584 # external_acl_type directive.
586 acl aclname user_cert attribute values...
587 # match against attributes in a user SSL certificate
588 # attribute is one of DN/C/O/CN/L/ST
590 acl aclname ca_cert attribute values...
591 # match against attributes a users issuing CA SSL certificate
592 # attribute is one of DN/C/O/CN/L/ST
594 acl aclname ext_user username ...
595 acl aclname ext_user_regex [-i] pattern ...
596 # string match on username returned by external acl helper
597 # use REQUIRED to accept any non-null user name.
600 acl macaddress arp 09:00:2b:23:45:67
601 acl myexample dst_as 1241
602 acl password proxy_auth REQUIRED
603 acl fileupload req_mime_type -i ^multipart/form-data$
604 acl javascript rep_mime_type -i ^application/x-javascript$
607 #Recommended minimum configuration:
608 acl manager proto cache_object
609 acl localhost src 127.0.0.1/32
610 acl to_localhost dst 127.0.0.0/8
612 # Example rule allowing access from your local networks.
613 # Adapt to list your (internal) IP networks from where browsing
615 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
616 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
617 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
619 acl SSL_ports port 443
620 acl Safe_ports port 80 # http
621 acl Safe_ports port 21 # ftp
622 acl Safe_ports port 443 # https
623 acl Safe_ports port 70 # gopher
624 acl Safe_ports port 210 # wais
625 acl Safe_ports port 1025-65535 # unregistered ports
626 acl Safe_ports port 280 # http-mgmt
627 acl Safe_ports port 488 # gss-http
628 acl Safe_ports port 591 # filemaker
629 acl Safe_ports port 777 # multiling http
630 acl CONNECT method CONNECT
636 LOC: Config.accessList.http
638 DEFAULT_IF_NONE: deny all
640 Allowing or Denying access based on defined access lists
642 Access to the HTTP port:
643 http_access allow|deny [!]aclname ...
645 NOTE on default values:
647 If there are no "access" lines present, the default is to deny
650 If none of the "access" lines cause a match, the default is the
651 opposite of the last line in the list. If the last line was
652 deny, the default is allow. Conversely, if the last line
653 is allow, the default will be deny. For these reasons, it is a
654 good idea to have an "deny all" or "allow all" entry at the end
655 of your access lists to avoid potential confusion.
658 #Recommended minimum configuration:
660 # Only allow cachemgr access from localhost
661 http_access allow manager localhost
662 http_access deny manager
663 # Deny requests to unknown ports
664 http_access deny !Safe_ports
665 # Deny CONNECT to other than SSL ports
666 http_access deny CONNECT !SSL_ports
668 # We strongly recommend the following be uncommented to protect innocent
669 # web applications running on the proxy server who think the only
670 # one who can access services on "localhost" is a local user
671 #http_access deny to_localhost
673 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
675 # Example rule allowing access from your local networks.
676 # Adapt localnet in the ACL section to list your (internal) IP networks
677 # from where browsing should be allowed
678 http_access allow localnet
680 # And finally deny all other access to this proxy
685 NAME: http_reply_access
687 LOC: Config.accessList.reply
690 Allow replies to client requests. This is complementary to http_access.
692 http_reply_access allow|deny [!] aclname ...
694 NOTE: if there are no access lines present, the default is to allow
697 If none of the access lines cause a match the opposite of the
698 last line will apply. Thus it is good practice to end the rules
699 with an "allow all" or "deny all" entry.
704 LOC: Config.accessList.icp
706 DEFAULT_IF_NONE: deny all
708 Allowing or Denying access to the ICP port based on defined
711 icp_access allow|deny [!]aclname ...
713 See http_access for details
716 #Allow ICP queries from local networks only
717 icp_access allow localnet
725 LOC: Config.accessList.htcp
727 DEFAULT_IF_NONE: deny all
729 Allowing or Denying access to the HTCP port based on defined
732 htcp_access allow|deny [!]aclname ...
734 See http_access for details
736 NOTE: The default if no htcp_access lines are present is to
737 deny all traffic. This default may cause problems with peers
738 using the htcp or htcp-oldsquid options.
741 #Allow HTCP queries from local networks only
742 htcp_access allow localnet
747 NAME: htcp_clr_access
750 LOC: Config.accessList.htcp_clr
752 DEFAULT_IF_NONE: deny all
754 Allowing or Denying access to purge content using HTCP based
755 on defined access lists
757 htcp_clr_access allow|deny [!]aclname ...
759 See http_access for details
761 #Allow HTCP CLR requests from trusted peers
762 acl htcp_clr_peer src 172.16.1.2
763 htcp_clr_access allow htcp_clr_peer
768 LOC: Config.accessList.miss
771 Use to force your neighbors to use you as a sibling instead of
772 a parent. For example:
774 acl localclients src 172.16.0.0/16
775 miss_access allow localclients
776 miss_access deny !localclients
778 This means only your local clients are allowed to fetch
779 MISSES and all other clients can only fetch HITS.
781 By default, allow all clients who passed the http_access rules
782 to fetch MISSES from us.
786 # miss_access allow all
790 NAME: ident_lookup_access
794 DEFAULT_IF_NONE: deny all
795 LOC: Config.accessList.identLookup
797 A list of ACL elements which, if matched, cause an ident
798 (RFC 931) lookup to be performed for this request. For
799 example, you might choose to always perform ident lookups
800 for your main multi-user Unix boxes, but not for your Macs
801 and PCs. By default, ident lookups are not performed for
804 To enable ident lookups for specific client addresses, you
805 can follow this example:
807 acl ident_aware_hosts src 198.168.1.0/255.255.255.0
808 ident_lookup_access allow ident_aware_hosts
809 ident_lookup_access deny all
811 Only src type ACL checks are fully supported. A src_domain
812 ACL might work at times, but it will not always provide
816 NAME: reply_body_max_size
817 COMMENT: size [acl acl...]
820 LOC: Config.ReplyBodySize
822 This option specifies the maximum size of a reply body. It can be
823 used to prevent users from downloading very large files, such as
824 MP3's and movies. When the reply headers are received, the
825 reply_body_max_size lines are processed, and the first line where
826 all (if any) listed ACLs are true is used as the maximum body size
829 This size is checked twice. First when we get the reply headers,
830 we check the content-length value. If the content length value exists
831 and is larger than the allowed size, the request is denied and the
832 user receives an error message that says "the request or reply
833 is too large." If there is no content-length, and the reply
834 size exceeds this limit, the client's connection is just closed
835 and they will receive a partial reply.
837 WARNING: downstream caches probably can not detect a partial reply
838 if there is no content-length header, so they will cache
839 partial responses and give them out as hits. You should NOT
840 use this option if you have downstream caches.
842 WARNING: A maximum size smaller than the size of squid's error messages
843 will cause an infinite loop and crash squid. Ensure that the smallest
844 non-zero value you use is greater that the maximum header size plus
845 the size of your largest error page.
847 If you set this parameter none (the default), there will be
853 -----------------------------------------------------------------------------
856 NAME: http_port ascii_port
859 LOC: Config.Sockaddr.http
861 Usage: port [options]
862 hostname:port [options]
863 1.2.3.4:port [options]
865 The socket addresses where Squid will listen for HTTP client
866 requests. You may specify multiple socket addresses.
867 There are three forms: port alone, hostname with port, and
868 IP address with port. If you specify a hostname or IP
869 address, Squid binds the socket to that specific
870 address. This replaces the old 'tcp_incoming_address'
871 option. Most likely, you do not need to bind to a specific
872 address, so you can use the port number alone.
874 If you are running Squid in accelerator mode, you
875 probably want to listen on port 80 also, or instead.
877 The -a command line option may be used to specify additional
878 port(s) where Squid listens for proxy request. Such ports will
879 be plain proxy ports with no options.
881 You may specify multiple socket addresses on multiple lines.
885 transparent Support for transparent interception of
886 outgoing requests without browser settings.
888 tproxy Support Linux TPROXY for spoofing outgoing
889 connections using the client IP address.
891 accel Accelerator mode. Also needs at least one of
892 vhost / vport / defaultsite.
894 defaultsite=domainname
895 What to use for the Host: header if it is not present
896 in a request. Determines what site (not origin server)
897 accelerators should consider the default.
900 vhost Accelerator mode using Host header for virtual
901 domain support. Implies accel.
903 vport Accelerator with IP based virtual host support.
906 vport=NN As above, but uses specified port number rather
907 than the http_port number. Implies accel.
909 protocol= Protocol to reconstruct accelerated requests with.
912 disable-pmtu-discovery=
913 Control Path-MTU discovery usage:
914 off lets OS decide on what to do (default).
915 transparent disable PMTU discovery when transparent
917 always disable always PMTU discovery.
919 In many setups of transparently intercepting proxies
920 Path-MTU discovery can not work on traffic towards the
921 clients. This is the case when the intercepting device
922 does not fully track connections and fails to forward
923 ICMP must fragment messages to the cache server. If you
924 have such setup and experience that certain clients
925 sporadically hang or never complete requests set
926 disable-pmtu-discovery option to 'transparent'.
928 If you run Squid on a dual-homed machine with an internal
929 and an external interface we recommend you to specify the
930 internal address:port in http_port. This way Squid will only be
931 visible on the internal address.
934 # Squid normally listens to port 3128
935 http_port @DEFAULT_HTTP_PORT@
941 TYPE: https_port_list
943 LOC: Config.Sockaddr.https
945 Usage: [ip:]port cert=certificate.pem [key=key.pem] [options...]
947 The socket address where Squid will listen for HTTPS client
950 This is really only useful for situations where you are running
951 squid in accelerator mode and you want to do the SSL work at the
954 You may specify multiple socket addresses on multiple lines,
955 each with their own SSL certificate and/or options.
959 accel Accelerator mode. Also needs at least one of
960 defaultsite or vhost.
962 defaultsite= The name of the https site presented on
963 this port. Implies accel.
965 vhost Accelerator mode using Host header for virtual
966 domain support. Requires a wildcard certificate
967 or other certificate valid for more than one domain.
970 protocol= Protocol to reconstruct accelerated requests with.
973 cert= Path to SSL certificate (PEM format).
975 key= Path to SSL private key file (PEM format)
976 if not specified, the certificate file is
977 assumed to be a combined certificate and
980 version= The version of SSL/TLS supported
981 1 automatic (default)
986 cipher= Colon separated list of supported ciphers.
988 options= Various SSL engine options. The most important
990 NO_SSLv2 Disallow the use of SSLv2
991 NO_SSLv3 Disallow the use of SSLv3
992 NO_TLSv1 Disallow the use of TLSv1
993 SINGLE_DH_USE Always create a new key when using
994 temporary/ephemeral DH key exchanges
995 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
996 documentation for a complete list of options.
998 clientca= File containing the list of CAs to use when
999 requesting a client certificate.
1001 cafile= File containing additional CA certificates to
1002 use when verifying client certificates. If unset
1003 clientca will be used.
1005 capath= Directory containing additional CA certificates
1006 and CRL lists to use when verifying client certificates.
1008 crlfile= File of additional CRL lists to use when verifying
1009 the client certificate, in addition to CRLs stored in
1010 the capath. Implies VERIFY_CRL flag below.
1012 dhparams= File containing DH parameters for temporary/ephemeral
1015 sslflags= Various flags modifying the use of SSL:
1017 Don't request client certificates
1018 immediately, but wait until acl processing
1019 requires a certificate (not yet implemented).
1021 Don't use the default CA lists built in
1024 Don't allow for session reuse. Each connection
1025 will result in a new SSL session.
1027 Verify CRL lists when accepting client
1030 Verify CRL lists for all certificates in the
1031 client certificate chain.
1033 sslcontext= SSL session ID context identifier.
1035 vport Accelerator with IP based virtual host support.
1037 vport=NN As above, but uses specified port number rather
1038 than the https_port number. Implies accel.
1042 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1045 LOC: Config.accessList.outgoing_tos
1047 Allows you to select a TOS/Diffserv value to mark outgoing
1048 connections with, based on the username or source address
1051 tcp_outgoing_tos ds-field [!]aclname ...
1053 Example where normal_service_net uses the TOS value 0x00
1054 and normal_service_net uses 0x20
1056 acl normal_service_net src 10.0.0.0/255.255.255.0
1057 acl good_service_net src 10.0.1.0/255.255.255.0
1058 tcp_outgoing_tos 0x00 normal_service_net
1059 tcp_outgoing_tos 0x20 good_service_net
1061 TOS/DSCP values really only have local significance - so you should
1062 know what you're specifying. For more information, see RFC2474 and
1065 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1066 "default" to use whatever default your host has. Note that in
1067 practice often only values 0 - 63 is usable as the two highest bits
1068 have been redefined for use by ECN (RFC3168).
1070 Processing proceeds in the order specified, and stops at first fully
1073 Note: The use of this directive using client dependent ACLs is
1074 incompatible with the use of server side persistent connections. To
1075 ensure correct results it is best to set server_persisten_connections
1076 to off when using this directive in such configurations.
1079 NAME: clientside_tos
1082 LOC: Config.accessList.clientside_tos
1084 Allows you to select a TOS/Diffserv value to mark client-side
1085 connections with, based on the username or source address
1089 NAME: tcp_outgoing_address
1092 LOC: Config.accessList.outgoing_address
1094 Allows you to map requests to different outgoing IP addresses
1095 based on the username or source address of the user making
1098 tcp_outgoing_address ipaddr [[!]aclname] ...
1100 Example where requests from 10.0.0.0/24 will be forwarded
1101 with source address 10.1.0.1, 10.0.2.0/24 forwarded with
1102 source address 10.1.0.2 and the rest will be forwarded with
1103 source address 10.1.0.3.
1105 acl normal_service_net src 10.0.0.0/255.255.255.0
1106 acl good_service_net src 10.0.1.0/255.255.255.0
1107 tcp_outgoing_address 10.0.0.1 normal_service_net
1108 tcp_outgoing_address 10.0.0.2 good_service_net
1109 tcp_outgoing_address 10.0.0.3
1111 Processing proceeds in the order specified, and stops at first fully
1114 Note: The use of this directive using client dependent ACLs is
1115 incompatible with the use of server side persistent connections. To
1116 ensure correct results it is best to set server_persistent_connections
1117 to off when using this directive in such configurations.
1122 Squid is built with a capability of bridging the IPv4 and IPv6 internets.
1123 tcp_outgoing_address as exampled above breaks this bridging by forcing
1124 all outbound traffic through a certain IPv4 which may be on the wrong
1125 side of the IPv4/IPv6 boundary.
1127 To operate with tcp_outgoing_address and keep the bridging benefits
1128 an additional ACL needs to be used which ensures the IPv6-bound traffic
1129 is never forced or permitted out the IPv4 interface.
1131 acl to_ipv6 dst ipv6
1132 tcp_outgoing_address 2002::c001 good_service_net to_ipv6
1133 tcp_outgoing_address 10.0.0.2 good_service_net !to_ipv6
1135 tcp_outgoing_address 2002::beef normal_service_net to_ipv6
1136 tcp_outgoing_address 10.0.0.1 normal_service_net !to_ipv6
1138 tcp_outgoing_address 2002::1 to_ipv6
1139 tcp_outgoing_address 10.0.0.3 !to_ipv6
1144 -----------------------------------------------------------------------------
1147 NAME: ssl_unclean_shutdown
1151 LOC: Config.SSL.unclean_shutdown
1153 Some browsers (especially MSIE) bugs out on SSL shutdown
1160 LOC: Config.SSL.ssl_engine
1163 The OpenSSL engine to use. You will need to set this if you
1164 would like to use hardware SSL acceleration for example.
1167 NAME: sslproxy_client_certificate
1170 LOC: Config.ssl_client.cert
1173 Client SSL Certificate to use when proxying https:// URLs
1176 NAME: sslproxy_client_key
1179 LOC: Config.ssl_client.key
1182 Client SSL Key to use when proxying https:// URLs
1185 NAME: sslproxy_version
1188 LOC: Config.ssl_client.version
1191 SSL version level to use when proxying https:// URLs
1194 NAME: sslproxy_options
1197 LOC: Config.ssl_client.options
1200 SSL engine options to use when proxying https:// URLs
1203 NAME: sslproxy_cipher
1206 LOC: Config.ssl_client.cipher
1209 SSL cipher list to use when proxying https:// URLs
1212 NAME: sslproxy_cafile
1215 LOC: Config.ssl_client.cafile
1218 file containing CA certificates to use when verifying server
1219 certificates while proxying https:// URLs
1222 NAME: sslproxy_capath
1225 LOC: Config.ssl_client.capath
1228 directory containing CA certificates to use when verifying
1229 server certificates while proxying https:// URLs
1232 NAME: sslproxy_flags
1235 LOC: Config.ssl_client.flags
1238 Various flags modifying the use of SSL while proxying https:// URLs:
1239 DONT_VERIFY_PEER Accept certificates even if they fail to
1241 NO_DEFAULT_CA Don't use the default CA list built in
1245 NAME: sslpassword_program
1248 LOC: Config.Program.ssl_password
1251 Specify a program used for entering SSL key passphrases
1252 when using encrypted SSL certificate keys. If not specified
1253 keys must either be unencrypted, or Squid started with the -N
1254 option to allow it to query interactively for the passphrase.
1258 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
1259 -----------------------------------------------------------------------------
1267 To specify other caches in a hierarchy, use the format:
1269 cache_peer hostname type http-port icp-port [options]
1274 # hostname type port port options
1275 # -------------------- -------- ----- ----- -----------
1276 cache_peer parent.foo.net parent 3128 3130 proxy-only default
1277 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
1278 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
1280 type: either 'parent', 'sibling', or 'multicast'.
1282 proxy-port: The port number where the cache listens for proxy
1285 icp-port: Used for querying neighbor caches about
1286 objects. To have a non-ICP neighbor
1287 specify '7' for the ICP port and make sure the
1288 neighbor machine has the UDP echo port
1289 enabled in its /etc/inetd.conf file.
1290 NOTE: Also requires icp_port option enabled to send/receive
1291 requests via this method.
1301 weighted-round-robin
1308 login=user:password | PASS | *:password
1319 sslcert=/path/to/ssl/certificate
1320 sslkey=/path/to/ssl/key
1324 front-end-https[=on|auto]
1326 use 'proxy-only' to specify objects fetched
1327 from this cache should not be saved locally.
1329 use 'weight=n' to affect the selection of a peer
1330 during any weighted peer-selection mechanisms.
1331 The weight must be an integer; default is 1,
1332 larger weights are favored more.
1333 This option does not affect parent selection if a peering
1334 protocol is not in use.
1336 use 'basetime=n' to specify a base amount to
1337 be subtracted from round trip times of parents.
1338 It is subtracted before division by weight in calculating
1339 which parent to fectch from. If the rtt is less than the
1340 base time the rtt is set to a minimal value.
1342 use 'ttl=n' to specify a IP multicast TTL to use
1343 when sending an ICP queries to this address.
1344 Only useful when sending to a multicast group.
1345 Because we don't accept ICP replies from random
1346 hosts, you must configure other group members as
1347 peers with the 'multicast-responder' option below.
1349 use 'no-query' to NOT send ICP queries to this
1352 use 'background-ping' to only send ICP queries to this
1353 neighbor infrequently. This is used to keep the neighbor
1354 round trip time updated and is usually used in
1355 conjunction with weighted-round-robin.
1357 use 'default' if this is a parent cache which can
1358 be used as a "last-resort" if a peer cannot be located
1359 by any of the peer-selection mechanisms.
1360 If specified more than once, only the first is used.
1362 use 'round-robin' to define a set of parents which
1363 should be used in a round-robin fashion in the
1364 absence of any ICP queries.
1366 use 'weighted-round-robin' to define a set of parents
1367 which should be used in a round-robin fashion with the
1368 frequency of each parent being based on the round trip
1369 time. Closer parents are used more often.
1370 Usually used for background-ping parents.
1372 use 'carp' to define a set of parents which should
1373 be used as a CARP array. The requests will be
1374 distributed among the parents based on the CARP load
1375 balancing hash function based on their weight.
1377 'multicast-responder' indicates the named peer
1378 is a member of a multicast group. ICP queries will
1379 not be sent directly to the peer, but ICP replies
1380 will be accepted from it.
1382 'closest-only' indicates that, for ICP_OP_MISS
1383 replies, we'll only forward CLOSEST_PARENT_MISSes
1384 and never FIRST_PARENT_MISSes.
1386 use 'no-digest' to NOT request cache digests from
1389 'no-netdb-exchange' disables requesting ICMP
1390 RTT database (NetDB) from the neighbor.
1392 use 'no-delay' to prevent access to this neighbor
1393 from influencing the delay pools.
1395 use 'login=user:password' if this is a personal/workgroup
1396 proxy and your parent requires proxy authentication.
1397 Note: The string can include URL escapes (i.e. %20 for
1398 spaces). This also means % must be written as %%.
1400 use 'login=PASS' if users must authenticate against
1401 the upstream proxy or in the case of a reverse proxy
1402 configuration, the origin web server. This will pass
1403 the users credentials as they are to the peer.
1404 This only works for the Basic HTTP authentication scheme.
1405 Note: To combine this with proxy_auth both proxies must
1406 share the same user database as HTTP only allows for
1407 a single login (one for proxy, one for origin server).
1408 Also be warned this will expose your users proxy
1409 password to the peer. USE WITH CAUTION
1411 use 'login=*:password' to pass the username to the
1412 upstream cache, but with a fixed password. This is meant
1413 to be used when the peer is in another administrative
1414 domain, but it is still needed to identify each user.
1415 The star can optionally be followed by some extra
1416 information which is added to the username. This can
1417 be used to identify this proxy to the peer, similar to
1418 the login=username:password option above.
1420 use 'connect-timeout=nn' to specify a peer
1421 specific connect timeout (also see the
1422 peer_connect_timeout directive)
1424 use 'digest-url=url' to tell Squid to fetch the cache
1425 digest (if digests are enabled) for this host from
1426 the specified URL rather than the Squid default
1429 use 'allow-miss' to disable Squid's use of only-if-cached
1430 when forwarding requests to siblings. This is primarily
1431 useful when icp_hit_stale is used by the sibling. To
1432 extensive use of this option may result in forwarding
1433 loops, and you should avoid having two-way peerings
1434 with this option. (for example to deny peer usage on
1435 requests from peer by denying cache_peer_access if the
1438 use 'max-conn=n' to limit the amount of connections Squid
1439 may open to this peer.
1441 use 'htcp' to send HTCP, instead of ICP, queries
1442 to the neighbor. You probably also want to
1443 set the "icp port" to 4827 instead of 3130.
1444 You MUST also set htcp_access expicitly. The default of
1445 deny all will prevent peer traffic.
1447 use 'htcp-oldsquid' to send HTCP to old Squid versions
1448 You MUST also set htcp_access expicitly. The default of
1449 deny all will prevent peer traffic.
1451 'originserver' causes this parent peer to be contacted as
1452 a origin server. Meant to be used in accelerator setups.
1454 use 'name=xxx' if you have multiple peers on the same
1455 host but different ports. This name can be used to
1456 differentiate the peers in cache_peer_access and similar
1459 use 'forceddomain=name' to forcibly set the Host header
1460 of requests forwarded to this peer. Useful in accelerator
1461 setups where the server (peer) expects a certain domain
1462 name and using redirectors to feed this domain name
1465 use 'ssl' to indicate connections to this peer should
1466 be SSL/TLS encrypted.
1468 use 'sslcert=/path/to/ssl/certificate' to specify a client
1469 SSL certificate to use when connecting to this peer.
1471 use 'sslkey=/path/to/ssl/key' to specify the private SSL
1472 key corresponding to sslcert above. If 'sslkey' is not
1473 specified 'sslcert' is assumed to reference a
1474 combined file containing both the certificate and the key.
1476 use sslversion=1|2|3|4 to specify the SSL version to use
1477 when connecting to this peer
1478 1 = automatic (default)
1483 use sslcipher=... to specify the list of valid SSL ciphers
1484 to use when connecting to this peer.
1486 use ssloptions=... to specify various SSL engine options:
1487 NO_SSLv2 Disallow the use of SSLv2
1488 NO_SSLv3 Disallow the use of SSLv3
1489 NO_TLSv1 Disallow the use of TLSv1
1490 See src/ssl_support.c or the OpenSSL documentation for
1491 a more complete list.
1493 use sslcafile=... to specify a file containing
1494 additional CA certificates to use when verifying the
1497 use sslcapath=... to specify a directory containing
1498 additional CA certificates to use when verifying the
1501 use sslcrlfile=... to specify a certificate revocation
1502 list file to use when verifying the peer certificate.
1504 use sslflags=... to specify various flags modifying the
1507 Accept certificates even if they fail to
1510 Don't use the default CA list built in
1513 Don't verify the peer certificate
1514 matches the server name
1516 use ssldomain= to specify the peer name as advertised
1517 in it's certificate. Used for verifying the correctness
1518 of the received peer certificate. If not specified the
1519 peer hostname will be used.
1521 use front-end-https to enable the "Front-End-Https: On"
1522 header needed when using Squid as a SSL frontend in front
1523 of Microsoft OWA. See MS KB document Q307347 for details
1524 on this header. If set to auto the header will
1525 only be added if the request is forwarded as a https://
1529 NAME: cache_peer_domain cache_host_domain
1534 Use to limit the domains for which a neighbor cache will be
1537 cache_peer_domain cache-host domain [domain ...]
1538 cache_peer_domain cache-host !domain
1540 For example, specifying
1542 cache_peer_domain parent.foo.net .edu
1544 has the effect such that UDP query packets are sent to
1545 'bigserver' only when the requested object exists on a
1546 server in the .edu domain. Prefixing the domainname
1547 with '!' means the cache will be queried for objects
1550 NOTE: * Any number of domains may be given for a cache-host,
1551 either on the same or separate lines.
1552 * When multiple domains are given for a particular
1553 cache-host, the first matched domain is applied.
1554 * Cache hosts with no domain restrictions are queried
1556 * There are no defaults.
1557 * There is also a 'cache_peer_access' tag in the ACL
1561 NAME: cache_peer_access
1566 Similar to 'cache_peer_domain' but provides more flexibility by
1569 cache_peer_access cache-host allow|deny [!]aclname ...
1571 The syntax is identical to 'http_access' and the other lists of
1572 ACL elements. See the comments for 'http_access' below, or
1573 the Squid FAQ (http://www.squid-cache.org/FAQ/FAQ-10.html).
1576 NAME: neighbor_type_domain
1577 TYPE: hostdomaintype
1581 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
1583 Modifying the neighbor type for specific domains is now
1584 possible. You can treat some domains differently than the the
1585 default neighbor type specified on the 'cache_peer' line.
1586 Normally it should only be necessary to list domains which
1587 should be treated differently because the default neighbor type
1588 applies for hostnames which do not match domains listed here.
1591 cache_peer cache.foo.org parent 3128 3130
1592 neighbor_type_domain cache.foo.org sibling .com .net
1593 neighbor_type_domain cache.foo.org sibling .au .de
1596 NAME: dead_peer_timeout
1600 LOC: Config.Timeout.deadPeer
1602 This controls how long Squid waits to declare a peer cache
1603 as "dead." If there are no ICP replies received in this
1604 amount of time, Squid will declare the peer dead and not
1605 expect to receive any further ICP replies. However, it
1606 continues to send ICP queries, and will mark the peer as
1607 alive upon receipt of the first subsequent ICP reply.
1609 This timeout also affects when Squid expects to receive ICP
1610 replies from peers. If more than 'dead_peer' seconds have
1611 passed since the last ICP reply was received, Squid will not
1612 expect to receive an ICP reply on the next query. Thus, if
1613 your time between requests is greater than this timeout, you
1614 will see a lot of requests sent DIRECT to origin servers
1615 instead of to your parents.
1618 NAME: hierarchy_stoplist
1621 LOC: Config.hierarchy_stoplist
1623 A list of words which, if found in a URL, cause the object to
1624 be handled directly by this cache. In other words, use this
1625 to not query neighbor caches for certain objects. You may
1626 list this option multiple times.
1627 Note: never_direct overrides this option.
1629 #We recommend you to use at least the following line.
1630 hierarchy_stoplist cgi-bin ?
1635 MEMORY CACHE OPTIONS
1636 -----------------------------------------------------------------------------
1643 LOC: Config.memMaxSize
1645 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
1646 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
1647 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
1648 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
1650 'cache_mem' specifies the ideal amount of memory to be used
1652 * In-Transit objects
1654 * Negative-Cached objects
1656 Data for these objects are stored in 4 KB blocks. This
1657 parameter specifies the ideal upper limit on the total size of
1658 4 KB blocks allocated. In-Transit objects take the highest
1661 In-transit objects have priority over the others. When
1662 additional space is needed for incoming data, negative-cached
1663 and hot objects will be released. In other words, the
1664 negative-cached and hot objects will fill up any unused space
1665 not needed for in-transit objects.
1667 If circumstances require, this limit will be exceeded.
1668 Specifically, if your incoming request rate requires more than
1669 'cache_mem' of memory to hold in-transit objects, Squid will
1670 exceed this limit to satisfy the new requests. When the load
1671 decreases, blocks will be freed until the high-water mark is
1672 reached. Thereafter, blocks will be used to store hot
1676 NAME: maximum_object_size_in_memory
1680 LOC: Config.Store.maxInMemObjSize
1682 Objects greater than this size will not be attempted to kept in
1683 the memory cache. This should be set high enough to keep objects
1684 accessed frequently in memory to improve performance whilst low
1685 enough to keep larger objects from hoarding cache_mem.
1688 NAME: memory_replacement_policy
1690 LOC: Config.memPolicy
1693 The memory replacement policy parameter determines which
1694 objects are purged from memory when memory space is needed.
1696 See cache_replacement_policy for details.
1701 -----------------------------------------------------------------------------
1704 NAME: cache_replacement_policy
1706 LOC: Config.replPolicy
1709 The cache replacement policy parameter determines which
1710 objects are evicted (replaced) when disk space is needed.
1712 lru : Squid's original list based LRU policy
1713 heap GDSF : Greedy-Dual Size Frequency
1714 heap LFUDA: Least Frequently Used with Dynamic Aging
1715 heap LRU : LRU policy implemented using a heap
1717 Applies to any cache_dir lines listed below this.
1719 The LRU policies keeps recently referenced objects.
1721 The heap GDSF policy optimizes object hit rate by keeping smaller
1722 popular objects in cache so it has a better chance of getting a
1723 hit. It achieves a lower byte hit rate than LFUDA though since
1724 it evicts larger (possibly popular) objects.
1726 The heap LFUDA policy keeps popular objects in cache regardless of
1727 their size and thus optimizes byte hit rate at the expense of
1728 hit rate since one large, popular object will prevent many
1729 smaller, slightly less popular objects from being cached.
1731 Both policies utilize a dynamic aging mechanism that prevents
1732 cache pollution that can otherwise occur with frequency-based
1733 replacement policies.
1735 NOTE: if using the LFUDA replacement policy you should increase
1736 the value of maximum_object_size above its default of 4096 KB to
1737 to maximize the potential byte hit rate improvement of LFUDA.
1739 For more information about the GDSF and LFUDA cache replacement
1740 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
1741 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
1747 DEFAULT_IF_NONE: ufs @DEFAULT_SWAP_DIR@ 100 16 256
1748 LOC: Config.cacheSwap
1752 cache_dir Type Directory-Name Fs-specific-data [options]
1754 You can specify multiple cache_dir lines to spread the
1755 cache among different disk partitions.
1757 Type specifies the kind of storage system to use. Only "ufs"
1758 is built by default. To enable any of the other storage systems
1759 see the --enable-storeio configure option.
1761 'Directory' is a top-level directory where cache swap
1762 files will be stored. If you want to use an entire disk
1763 for caching, this can be the mount-point directory.
1764 The directory must exist and be writable by the Squid
1765 process. Squid will NOT create this directory for you.
1769 "ufs" is the old well-known Squid storage format that has always
1772 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
1774 'Mbytes' is the amount of disk space (MB) to use under this
1775 directory. The default is 100 MB. Change this to suit your
1776 configuration. Do NOT put the size of your disk drive here.
1777 Instead, if you want Squid to use the entire disk drive,
1778 subtract 20% and use that value.
1780 'Level-1' is the number of first-level subdirectories which
1781 will be created under the 'Directory'. The default is 16.
1783 'Level-2' is the number of second-level subdirectories which
1784 will be created under each first-level directory. The default
1787 The aufs store type:
1789 "aufs" uses the same storage format as "ufs", utilizing
1790 POSIX-threads to avoid blocking the main Squid process on
1791 disk-I/O. This was formerly known in Squid as async-io.
1793 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
1795 see argument descriptions under ufs above
1797 The diskd store type:
1799 "diskd" uses the same storage format as "ufs", utilizing a
1800 separate process to avoid blocking the main Squid process on
1803 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
1805 see argument descriptions under ufs above
1807 Q1 specifies the number of unacknowledged I/O requests when Squid
1808 stops opening new files. If this many messages are in the queues,
1809 Squid won't open new files. Default is 64
1811 Q2 specifies the number of unacknowledged messages when Squid
1812 starts blocking. If this many messages are in the queues,
1813 Squid blocks until it receives some replies. Default is 72
1815 When Q1 < Q2 (the default), the cache directory is optimized
1816 for lower response time at the expense of a decrease in hit
1817 ratio. If Q1 > Q2, the cache directory is optimized for
1818 higher hit ratio at the expense of an increase in response
1821 The coss store type:
1823 block-size=n defines the "block size" for COSS cache_dir's.
1824 Squid uses file numbers as block numbers. Since file numbers
1825 are limited to 24 bits, the block size determines the maximum
1826 size of the COSS partition. The default is 512 bytes, which
1827 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
1828 you should not change the coss block size after Squid
1829 has written some objects to the cache_dir.
1831 The coss file store has changed from 2.5. Now it uses a file
1832 called 'stripe' in the directory names in the config - and
1833 this will be created by squid -z.
1835 The null store type:
1837 no options are allowed or required
1841 no-store, no new objects should be stored to this cache_dir
1843 max-size=n, refers to the max object size this storedir supports.
1844 It is used to initially choose the storedir to dump the object.
1845 Note: To make optimal use of the max-size limits you should order
1846 the cache_dir lines with the smallest max-size value first and the
1847 ones with no max-size specification last.
1849 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
1850 which can be changed with the --with-coss-membuf-size=N configure
1854 NAME: store_dir_select_algorithm
1856 LOC: Config.store_dir_select_algorithm
1859 Set this to 'round-robin' as an alternative.
1862 NAME: max_open_disk_fds
1864 LOC: Config.max_open_disk_fds
1867 To avoid having disk as the I/O bottleneck Squid can optionally
1868 bypass the on-disk cache if more than this amount of disk file
1869 descriptors are open.
1871 A value of 0 indicates no limit.
1874 NAME: minimum_object_size
1878 LOC: Config.Store.minObjectSize
1880 Objects smaller than this size will NOT be saved on disk. The
1881 value is specified in kilobytes, and the default is 0 KB, which
1882 means there is no minimum.
1885 NAME: maximum_object_size
1889 LOC: Config.Store.maxObjectSize
1891 Objects larger than this size will NOT be saved on disk. The
1892 value is specified in kilobytes, and the default is 4MB. If
1893 you wish to get a high BYTES hit ratio, you should probably
1894 increase this (one 32 MB object hit counts for 3200 10KB
1895 hits). If you wish to increase speed more than your want to
1896 save bandwidth you should leave this low.
1898 NOTE: if using the LFUDA replacement policy you should increase
1899 this value to maximize the byte hit rate improvement of LFUDA!
1900 See replacement_policy below for a discussion of this policy.
1903 NAME: cache_swap_low
1904 COMMENT: (percent, 0-100)
1907 LOC: Config.Swap.lowWaterMark
1910 NAME: cache_swap_high
1911 COMMENT: (percent, 0-100)
1914 LOC: Config.Swap.highWaterMark
1917 The low- and high-water marks for cache object replacement.
1918 Replacement begins when the swap (disk) usage is above the
1919 low-water mark and attempts to maintain utilization near the
1920 low-water mark. As swap utilization gets close to high-water
1921 mark object eviction becomes more aggressive. If utilization is
1922 close to the low-water mark less replacement is done each time.
1924 Defaults are 90% and 95%. If you have a large cache, 5% could be
1925 hundreds of MB. If this is the case you may wish to set these
1926 numbers closer together.
1931 -----------------------------------------------------------------------------
1936 LOC: Config.Log.logformats
1941 logformat <name> <format specification>
1943 Defines an access log format.
1945 The <format specification> is a string with embedded % format codes
1947 % format codes all follow the same basic structure where all but
1948 the formatcode is optional. Output strings are automatically escaped
1949 as required according to their context and the output format
1950 modifiers are usually not needed, but can be specified if an explicit
1951 output format is desired.
1953 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
1955 " output in quoted string format
1956 [ output in squid text log format as used by log_mime_hdrs
1957 # output in URL quoted format
1961 width field width. If starting with 0 the
1962 output is zero padded
1963 {arg} argument such as header name etc
1967 >a Client source IP address
1969 >p Client source port
1970 <A Server IP address or peer name
1971 la Local IP address (http_port)
1972 lp Local port number (http_port)
1973 ts Seconds since epoch
1974 tu subsecond time (milliseconds)
1975 tl Local time. Optional strftime format argument
1976 default %d/%b/%Y:%H:%M:%S %z
1977 tg GMT time. Optional strftime format argument
1978 default %d/%b/%Y:%H:%M:%S %z
1979 tr Response time (milliseconds)
1980 >h Request header. Optional header name argument
1981 on the format header[:[separator]element]
1982 <h Reply header. Optional header name argument
1985 ul User name from authentication
1986 ui User name from ident
1987 us User name from SSL
1988 ue User name from external acl helper
1990 Ss Squid request status (TCP_MISS etc)
1991 Sh Squid hierarchy status (DEFAULT_PARENT etc)
1992 mt MIME content type
1993 rm Request method (GET/POST etc)
1995 rp Request URL-Path excluding hostname
1996 rv Request protocol version
1997 et Tag returned by external acl
1998 ea Log string returned by external acl
1999 <st Reply size including HTTP headers
2000 <sH Reply high offset sent
2001 <sS Upstream object size
2002 % a literal % character
2004 logformat squid %ts.%03tu %6tr %>a %Ss/%03Hs %<st %rm %ru %un %Sh/%<A %mt
2005 logformat squidmime %ts.%03tu %6tr %>a %Ss/%03Hs %<st %rm %ru %un %Sh/%<A %mt [%>h] [%<h]
2006 logformat common %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %Hs %<st %Ss:%Sh
2007 logformat combined %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
2010 NAME: access_log cache_access_log
2012 LOC: Config.Log.accesslogs
2015 These files log client request activities. Has a line every HTTP or
2016 ICP request. The format is:
2017 access_log <filepath> [<logformat name> [acl acl ...]]
2018 access_log none [acl acl ...]]
2020 Will log to the specified file using the specified format (which
2021 must be defined in a logformat directive) those entries which match
2022 ALL the acl's specified (which must be defined in acl clauses).
2023 If no acl is specified, all requests will be logged to this file.
2025 To disable logging of a request use the filepath "none", in which case
2026 a logformat name should not be specified.
2028 To log the request via syslog specify a filepath of "syslog":
2030 access_log syslog[:facility.priority] [format [acl1 [acl2 ....]]]
2031 where facility could be any of:
2032 authpriv, daemon, local0 .. local7 or user.
2034 And priority could be any of:
2035 err, warning, notice, info, debug.
2037 access_log @DEFAULT_ACCESS_LOG@ squid
2043 LOC: Config.accessList.log
2045 COMMENT: allow|deny acl acl...
2047 This options allows you to control which requests gets logged
2048 to access.log (see access_log directive). Requests denied for
2049 logging will also not be accounted for in performance counters.
2054 DEFAULT: @DEFAULT_CACHE_LOG@
2057 Cache logging file. This is where general information about
2058 your cache's behavior goes. You can increase the amount of data
2059 logged to this file with the "debug_options" tag below.
2062 NAME: cache_store_log
2064 DEFAULT: @DEFAULT_STORE_LOG@
2065 LOC: Config.Log.store
2067 Logs the activities of the storage manager. Shows which
2068 objects are ejected from the cache, and which objects are
2069 saved and for how long. To disable, enter "none". There are
2070 not really utilities to analyze this data, so you can safely
2074 NAME: cache_swap_state cache_swap_log
2076 LOC: Config.Log.swap
2079 Location for the cache "swap.state" file. This index file holds
2080 the metadata of objects saved on disk. It is used to rebuild
2081 the cache during startup. Normally this file resides in each
2082 'cache_dir' directory, but you may specify an alternate
2083 pathname here. Note you must give a full filename, not just
2084 a directory. Since this is the index for the whole object
2085 list you CANNOT periodically rotate it!
2087 If %s can be used in the file name it will be replaced with a
2088 a representation of the cache_dir name where each / is replaced
2089 with '.'. This is needed to allow adding/removing cache_dir
2090 lines when cache_swap_log is being used.
2092 If have more than one 'cache_dir', and %s is not used in the name
2093 these swap logs will have names such as:
2099 The numbered extension (which is added automatically)
2100 corresponds to the order of the 'cache_dir' lines in this
2101 configuration file. If you change the order of the 'cache_dir'
2102 lines in this file, these index files will NOT correspond to
2103 the correct 'cache_dir' entry (unless you manually rename
2104 them). We recommend you do NOT use this option. It is
2105 better to keep these index files in each 'cache_dir' directory.
2108 NAME: logfile_rotate
2111 LOC: Config.Log.rotateNumber
2113 Specifies the number of logfile rotations to make when you
2114 type 'squid -k rotate'. The default is 10, which will rotate
2115 with extensions 0 through 9. Setting logfile_rotate to 0 will
2116 disable the file name rotation, but the logfiles are still closed
2117 and re-opened. This will enable you to rename the logfiles
2118 yourself just before sending the rotate signal.
2120 Note, the 'squid -k rotate' command normally sends a USR1
2121 signal to the running squid process. In certain situations
2122 (e.g. on Linux with Async I/O), USR1 is used for other
2123 purposes, so -k rotate uses another signal. It is best to get
2124 in the habit of using 'squid -k rotate' instead of 'kill -USR1
2128 NAME: emulate_httpd_log
2132 LOC: Config.onoff.common_log
2134 The Cache can emulate the log file format which many 'httpd'
2135 programs use. To disable/enable this emulation, set
2136 emulate_httpd_log to 'off' or 'on'. The default
2137 is to use the native log format since it includes useful
2138 information Squid-specific log analyzers use.
2141 NAME: log_ip_on_direct
2145 LOC: Config.onoff.log_ip_on_direct
2147 Log the destination IP address in the hierarchy log tag when going
2148 direct. Earlier Squid versions logged the hostname here. If you
2149 prefer the old way set this to off.
2154 DEFAULT: @DEFAULT_MIME_TABLE@
2155 LOC: Config.mimeTablePathname
2157 Pathname to Squid's MIME table. You shouldn't need to change
2158 this, but the default file contains examples and formatting
2159 information if you do.
2165 LOC: Config.onoff.log_mime_hdrs
2168 The Cache can record both the request and the response MIME
2169 headers for each HTTP transaction. The headers are encoded
2170 safely and will appear as two bracketed fields at the end of
2171 the access log (for either the native or httpd-emulated log
2172 formats). To enable this logging set log_mime_hdrs to 'on'.
2177 LOC: Config.Log.useragent
2179 IFDEF: USE_USERAGENT_LOG
2181 Squid will write the User-Agent field from HTTP requests
2182 to the filename specified here. By default useragent_log
2186 NAME: referer_log referrer_log
2188 LOC: Config.Log.referer
2190 IFDEF: USE_REFERER_LOG
2192 Squid will write the Referer field from HTTP requests to the
2193 filename specified here. By default referer_log is disabled.
2194 Note that "referer" is actually a misspelling of "referrer"
2195 however the misspelt version has been accepted into the HTTP RFCs
2201 DEFAULT: @DEFAULT_PID_FILE@
2202 LOC: Config.pidFilename
2204 A filename to write the process-id to. To disable, enter "none".
2210 LOC: Config.debugOptions
2212 Logging options are set as section,level where each source file
2213 is assigned a unique section. Lower levels result in less
2214 output, Full debugging (level 9) can result in a very large
2215 log file, so be careful. The magic word "ALL" sets debugging
2216 levels for all sections. We recommend normally running with
2224 LOC: Config.onoff.log_fqdn
2226 Turn this on if you wish to log fully qualified domain names
2227 in the access.log. To do this Squid does a DNS lookup of all
2228 IP's connecting to it. This can (in some situations) increase
2229 latency, which makes your cache seem slower for interactive
2233 NAME: client_netmask
2235 LOC: Config.Addrs.client_netmask
2236 DEFAULT: 255.255.255.255
2238 A netmask for client addresses in logfiles and cachemgr output.
2239 Change this to protect the privacy of your cache clients.
2240 A netmask of 255.255.255.0 will log all IP's in that range with
2241 the last digit set to '0'.
2248 LOC: Config.Log.forward
2250 Logs the server-side requests.
2252 This is currently work in progress.
2255 NAME: strip_query_terms
2257 LOC: Config.onoff.strip_query_terms
2260 By default, Squid strips query terms from requested URLs before
2261 logging. This protects your user's privacy.
2268 LOC: Config.onoff.buffered_logs
2270 cache.log log file is written with stdio functions, and as such
2271 it can be buffered or unbuffered. By default it will be unbuffered.
2272 Buffering it can speed up the writing slightly (though you are
2273 unlikely to need to worry unless you run with tons of debugging
2274 enabled in which case performance will suffer badly anyway..).
2278 OPTIONS FOR FTP GATEWAYING
2279 -----------------------------------------------------------------------------
2285 LOC: Config.Ftp.anon_user
2287 If you want the anonymous login password to be more informative
2288 (and enable the use of picky ftp servers), set this to something
2289 reasonable for your domain, like wwwuser@somewhere.net
2291 The reason why this is domainless by default is the
2292 request can be made on the behalf of a user in any domain,
2293 depending on how the cache is used.
2294 Some ftp server also validate the email address is valid
2295 (for example perl.com).
2298 NAME: ftp_list_width
2301 LOC: Config.Ftp.list_width
2303 Sets the width of ftp listings. This should be set to fit in
2304 the width of a standard browser. Setting this too small
2305 can cut off long filenames when browsing ftp sites.
2311 LOC: Config.Ftp.passive
2313 If your firewall does not allow Squid to use passive
2314 connections, turn off this option.
2317 NAME: ftp_sanitycheck
2320 LOC: Config.Ftp.sanitycheck
2322 For security and data integrity reasons Squid by default performs
2323 sanity checks of the addresses of FTP data connections ensure the
2324 data connection is to the requested server. If you need to allow
2325 FTP connections to servers using another IP address for the data
2326 connection turn this off.
2329 NAME: ftp_telnet_protocol
2332 LOC: Config.Ftp.telnet
2334 The FTP protocol is officially defined to use the telnet protocol
2335 as transport channel for the control connection. However, many
2336 implementations are broken and does not respect this aspect of
2339 If you have trouble accessing files with ASCII code 255 in the
2340 path or similar problems involving this ASCII code you can
2341 try setting this directive to off. If that helps, report to the
2342 operator of the FTP server in question that their FTP server
2343 is broken and does not follow the FTP standard.
2347 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
2348 -----------------------------------------------------------------------------
2353 DEFAULT: @DEFAULT_DISKD@
2354 LOC: Config.Program.diskd
2356 Specify the location of the diskd executable.
2357 Note this is only useful if you have compiled in
2358 diskd as one of the store io modules.
2361 NAME: unlinkd_program
2364 DEFAULT: @DEFAULT_UNLINKD@
2365 LOC: Config.Program.unlinkd
2367 Specify the location of the executable for file deletion process.
2370 NAME: pinger_program
2372 DEFAULT: @DEFAULT_PINGER@
2373 LOC: Config.pinger.program
2376 Specify the location of the executable for the pinger process.
2382 LOC: Config.pinger.enable
2385 Control whether the pinger is active at run-time.
2386 Enables turning ICMP pinger on and off with a simple squid -k reconfigure.
2391 OPTIONS FOR URL REWRITING
2392 -----------------------------------------------------------------------------
2395 NAME: url_rewrite_program redirect_program
2397 LOC: Config.Program.redirect
2400 Specify the location of the executable for the URL rewriter.
2401 Since they can perform almost any function there isn't one included.
2403 For each requested URL rewriter will receive on line with the format
2405 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
2407 In the future, the rewriter interface will be extended with
2408 key=value pairs ("kvpairs" shown above). Rewriter programs
2409 should be prepared to receive and possibly ignore additional
2410 whitespace-separated tokens on each input line.
2412 And the rewriter may return a rewritten URL. The other components of
2413 the request line does not need to be returned (ignored if they are).
2415 The rewriter can also indicate that a client-side redirect should
2416 be performed to the new URL. This is done by prefixing the returned
2417 URL with "301:" (moved permanently) or 302: (moved temporarily).
2419 By default, a URL rewriter is not used.
2422 NAME: url_rewrite_children redirect_children
2425 LOC: Config.redirectChildren
2427 The number of redirector processes to spawn. If you start
2428 too few Squid will have to wait for them to process a backlog of
2429 URLs, slowing it down. If you start too many they will use RAM
2430 and other system resources.
2433 NAME: url_rewrite_concurrency redirect_concurrency
2436 LOC: Config.redirectConcurrency
2438 The number of requests each redirector helper can handle in
2439 parallel. Defaults to 0 which indicates the redirector
2440 is a old-style single threaded redirector.
2443 NAME: url_rewrite_host_header redirect_rewrites_host_header
2446 LOC: Config.onoff.redir_rewrites_host
2448 By default Squid rewrites any Host: header in redirected
2449 requests. If you are running an accelerator this may
2450 not be a wanted effect of a redirector.
2452 WARNING: Entries are cached on the result of the URL rewriting
2453 process, so be careful if you have domain-virtual hosts.
2456 NAME: url_rewrite_access redirector_access
2459 LOC: Config.accessList.redirector
2461 If defined, this access list specifies which requests are
2462 sent to the redirector processes. By default all requests
2466 NAME: url_rewrite_bypass redirector_bypass
2468 LOC: Config.onoff.redirector_bypass
2471 When this is 'on', a request will not go through the
2472 redirector if all redirectors are busy. If this is 'off'
2473 and the redirector queue grows too large, Squid will exit
2474 with a FATAL error and ask you to increase the number of
2475 redirectors. You should only enable this if the redirectors
2476 are not critical to your caching system. If you use
2477 redirectors for access control, and you enable this option,
2478 users may have access to pages they should not
2479 be allowed to request.
2483 OPTIONS FOR TUNING THE CACHE
2484 -----------------------------------------------------------------------------
2487 NAME: cache no_cache
2490 LOC: Config.accessList.noCache
2492 A list of ACL elements which, if matched, cause the request to
2493 not be satisfied from the cache and the reply to not be cached.
2494 In other words, use this to force certain objects to never be cached.
2496 You must use the word 'DENY' to indicate the ACL names which should
2499 Default is to allow all to be cached
2501 #We recommend you to use the following two lines.
2502 acl QUERY urlpath_regex cgi-bin \?
2507 NAME: refresh_pattern
2508 TYPE: refreshpattern
2512 usage: refresh_pattern [-i] regex min percent max [options]
2514 By default, regular expressions are CASE-SENSITIVE. To make
2515 them case-insensitive, use the -i option.
2517 'Min' is the time (in minutes) an object without an explicit
2518 expiry time should be considered fresh. The recommended
2519 value is 0, any higher values may cause dynamic applications
2520 to be erroneously cached unless the application designer
2521 has taken the appropriate actions.
2523 'Percent' is a percentage of the objects age (time since last
2524 modification age) an object without explicit expiry time
2525 will be considered fresh.
2527 'Max' is an upper limit on how long objects without an explicit
2528 expiry time will be considered fresh.
2530 options: override-expire
2540 override-expire enforces min age even if the server
2541 sent a Expires: header. Doing this VIOLATES the HTTP
2542 standard. Enabling this feature could make you liable
2543 for problems which it causes.
2545 override-lastmod enforces min age even on objects
2546 that were modified recently.
2548 reload-into-ims changes client no-cache or ``reload''
2549 to If-Modified-Since requests. Doing this VIOLATES the
2550 HTTP standard. Enabling this feature could make you
2551 liable for problems which it causes.
2553 ignore-reload ignores a client no-cache or ``reload''
2554 header. Doing this VIOLATES the HTTP standard. Enabling
2555 this feature could make you liable for problems which
2558 ignore-no-cache ignores any ``Pragma: no-cache'' and
2559 ``Cache-control: no-cache'' headers received from a server.
2560 The HTTP RFC never allows the use of this (Pragma) header
2561 from a server, only a client, though plenty of servers
2564 ignore-no-store ignores any ``Cache-control: no-store''
2565 headers received from a server. Doing this VIOLATES
2566 the HTTP standard. Enabling this feature could make you
2567 liable for problems which it causes.
2569 ignore-private ignores any ``Cache-control: private''
2570 headers received from a server. Doing this VIOLATES
2571 the HTTP standard. Enabling this feature could make you
2572 liable for problems which it causes.
2574 ignore-auth caches responses to requests with authorization,
2575 as if the originserver had sent ``Cache-control: public''
2576 in the response header. Doing this VIOLATES the HTTP standard.
2577 Enabling this feature could make you liable for problems which
2580 refresh-ims causes squid to contact the origin server
2581 when a client issues an If-Modified-Since request. This
2582 ensures that the client will receive an updated version
2583 if one is available.
2585 Basically a cached object is:
2587 FRESH if expires < now, else STALE
2589 FRESH if lm-factor < percent, else STALE
2593 The refresh_pattern lines are checked in the order listed here.
2594 The first entry which matches is used. If none of the entries
2595 match the default will be used.
2597 Note, you must uncomment all the default lines if you want
2598 to change one. The default setting is only active if none is
2603 refresh_pattern ^ftp: 1440 20% 10080
2604 refresh_pattern ^gopher: 1440 0% 1440
2605 refresh_pattern . 0 20% 4320
2609 NAME: quick_abort_min
2613 LOC: Config.quickAbort.min
2616 NAME: quick_abort_max
2620 LOC: Config.quickAbort.max
2623 NAME: quick_abort_pct
2627 LOC: Config.quickAbort.pct
2629 The cache by default continues downloading aborted requests
2630 which are almost completed (less than 16 KB remaining). This
2631 may be undesirable on slow (e.g. SLIP) links and/or very busy
2632 caches. Impatient users may tie up file descriptors and
2633 bandwidth by repeatedly requesting and immediately aborting
2636 When the user aborts a request, Squid will check the
2637 quick_abort values to the amount of data transfered until
2640 If the transfer has less than 'quick_abort_min' KB remaining,
2641 it will finish the retrieval.
2643 If the transfer has more than 'quick_abort_max' KB remaining,
2644 it will abort the retrieval.
2646 If more than 'quick_abort_pct' of the transfer has completed,
2647 it will finish the retrieval.
2649 If you do not want any retrieval to continue after the client
2650 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
2653 If you want retrievals to always continue if they are being
2654 cached set 'quick_abort_min' to '-1 KB'.
2657 NAME: read_ahead_gap
2658 COMMENT: buffer-size
2660 LOC: Config.readAheadGap
2663 The amount of data the cache will buffer ahead of what has been
2664 sent to the client when retrieving an object from another server.
2670 LOC: Config.negativeTtl
2673 Time-to-Live (TTL) for failed requests. Certain types of
2674 failures (such as "connection refused" and "404 Not Found") are
2675 negatively-cached for a configurable amount of time. The
2676 default is 5 minutes. Note that this is different from
2677 negative caching of DNS lookups.
2680 NAME: positive_dns_ttl
2683 LOC: Config.positiveDnsTtl
2686 Upper limit on how long Squid will cache positive DNS responses.
2687 Default is 6 hours (360 minutes). This directive must be set
2688 larger than negative_dns_ttl.
2691 NAME: negative_dns_ttl
2694 LOC: Config.negativeDnsTtl
2697 Time-to-Live (TTL) for negative caching of failed DNS lookups.
2698 This also sets the lower cache limit on positive lookups.
2699 Minimum value is 1 second, and it is not recommendable to go
2700 much below 10 seconds.
2703 NAME: range_offset_limit
2706 LOC: Config.rangeOffsetLimit
2709 Sets a upper limit on how far into the the file a Range request
2710 may be to cause Squid to prefetch the whole file. If beyond this
2711 limit Squid forwards the Range request as it is and the result
2714 This is to stop a far ahead range request (lets say start at 17MB)
2715 from making Squid fetch the whole object up to that point before
2716 sending anything to the client.
2718 A value of -1 causes Squid to always fetch the object from the
2719 beginning so it may cache the result. (2.0 style)
2721 A value of 0 causes Squid to never fetch more than the
2722 client requested. (default)
2725 NAME: minimum_expiry_time
2728 LOC: Config.minimum_expiry_time
2731 The minimum caching time according to (Expires - Date)
2732 Headers Squid honors if the object can't be revalidated
2733 defaults to 60 seconds. In reverse proxy enorinments it
2734 might be desirable to honor shorter object lifetimes. It
2735 is most likely better to make your server return a
2736 meaningful Last-Modified header however. In ESI environments
2737 where page fragments often have short lifetimes, this will
2738 often be best set to 0.
2741 NAME: store_avg_object_size
2745 LOC: Config.Store.avgObjectSize
2747 Average object size, used to estimate number of objects your
2748 cache can hold. The default is 13 KB.
2751 NAME: store_objects_per_bucket
2754 LOC: Config.Store.objectsPerBucket
2756 Target number of objects per bucket in the store hash table.
2757 Lowering this value increases the total number of buckets and
2758 also the storage maintenance rate. The default is 20.
2763 -----------------------------------------------------------------------------
2766 NAME: request_header_max_size
2770 LOC: Config.maxRequestHeaderSize
2772 This specifies the maximum size for HTTP headers in a request.
2773 Request headers are usually relatively small (about 512 bytes).
2774 Placing a limit on the request header size will catch certain
2775 bugs (for example with persistent connections) and possibly
2776 buffer-overflow or denial-of-service attacks.
2779 NAME: reply_header_max_size
2783 LOC: Config.maxReplyHeaderSize
2785 This specifies the maximum size for HTTP headers in a reply.
2786 Reply headers are usually relatively small (about 512 bytes).
2787 Placing a limit on the reply header size will catch certain
2788 bugs (for example with persistent connections) and possibly
2789 buffer-overflow or denial-of-service attacks.
2792 NAME: request_body_max_size
2796 LOC: Config.maxRequestBodySize
2798 This specifies the maximum size for an HTTP request body.
2799 In other words, the maximum size of a PUT/POST request.
2800 A user who attempts to send a request with a body larger
2801 than this limit receives an "Invalid Request" error message.
2802 If you set this parameter to a zero (the default), there will
2803 be no limit imposed.
2809 LOC: Config.accessList.brokenPosts
2811 A list of ACL elements which, if matched, causes Squid to send
2812 an extra CRLF pair after the body of a PUT/POST request.
2814 Some HTTP servers has broken implementations of PUT/POST,
2815 and rely on an extra CRLF pair sent by some WWW clients.
2817 Quote from RFC2616 section 4.1 on this matter:
2819 Note: certain buggy HTTP/1.0 client implementations generate an
2820 extra CRLF's after a POST request. To restate what is explicitly
2821 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
2822 a request with an extra CRLF.
2825 acl buggy_server url_regex ^http://....
2826 broken_posts allow buggy_server
2830 IFDEF: HTTP_VIOLATIONS
2834 LOC: Config.onoff.via
2836 If set (default), Squid will include a Via header in requests and
2837 replies as required by RFC2616.
2843 LOC: Config.onoff.ie_refresh
2846 Microsoft Internet Explorer up until version 5.5 Service
2847 Pack 1 has an issue with transparent proxies, wherein it
2848 is impossible to force a refresh. Turning this on provides
2849 a partial fix to the problem, by causing all IMS-REFRESH
2850 requests from older IE versions to check the origin server
2851 for fresh content. This reduces hit ratio by some amount
2852 (~10% in my experience), but allows users to actually get
2853 fresh content when they want it. Note because Squid
2854 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
2855 of 5.5 is unchanged from old versions of Squid (i.e. a
2856 forced refresh is impossible). Newer versions of IE will,
2857 hopefully, continue to have the new behavior and will be
2858 handled based on that assumption. This option defaults to
2859 the old Squid behavior, which is better for hit ratios but
2860 worse for clients using IE, if they need to be able to
2861 force fresh content.
2864 NAME: vary_ignore_expire
2867 LOC: Config.onoff.vary_ignore_expire
2870 Many HTTP servers supporting Vary gives such objects
2871 immediate expiry time with no cache-control header
2872 when requested by a HTTP/1.0 client. This option
2873 enables Squid to ignore such expiry times until
2874 HTTP/1.1 is fully implemented.
2875 WARNING: This may eventually cause some varying
2876 objects not intended for caching to get cached.
2879 NAME: extension_methods
2881 LOC: Config.ext_methods
2884 Squid only knows about standardized HTTP request methods.
2885 You can add up to 20 additional "extension" methods here.
2888 NAME: request_entities
2890 LOC: Config.onoff.request_entities
2893 Squid defaults to deny GET and HEAD requests with request entities,
2894 as the meaning of such requests are undefined in the HTTP standard
2895 even if not explicitly forbidden.
2897 Set this directive to on if you have clients which insists
2898 on sending request entities in GET or HEAD requests. But be warned
2899 that there is server software (both proxies and web servers) which
2900 can fail to properly process this kind of request which may make you
2901 vulnerable to cache pollution attacks if enabled.
2904 NAME: request_header_access
2905 IFDEF: HTTP_VIOLATIONS
2906 TYPE: http_header_access[]
2907 LOC: Config.request_header_access
2910 Usage: request_header_access header_name allow|deny [!]aclname ...
2912 WARNING: Doing this VIOLATES the HTTP standard. Enabling
2913 this feature could make you liable for problems which it
2916 This option replaces the old 'anonymize_headers' and the
2917 older 'http_anonymizer' option with something that is much
2918 more configurable. This new method creates a list of ACLs
2919 for each header, allowing you very fine-tuned header
2922 This option only applies to request headers, i.e., from the
2923 client to the server.
2925 You can only specify known headers for the header name.
2926 Other headers are reclassified as 'Other'. You can also
2927 refer to all the headers with 'All'.
2929 For example, to achieve the same behavior as the old
2930 'http_anonymizer standard' option, you should use:
2932 request_header_access From deny all
2933 request_header_access Referer deny all
2934 request_header_access Server deny all
2935 request_header_access User-Agent deny all
2936 request_header_access WWW-Authenticate deny all
2937 request_header_access Link deny all
2939 Or, to reproduce the old 'http_anonymizer paranoid' feature
2942 request_header_access Allow allow all
2943 request_header_access Authorization allow all
2944 request_header_access WWW-Authenticate allow all
2945 request_header_access Proxy-Authorization allow all
2946 request_header_access Proxy-Authenticate allow all
2947 request_header_access Cache-Control allow all
2948 request_header_access Content-Encoding allow all
2949 request_header_access Content-Length allow all
2950 request_header_access Content-Type allow all
2951 request_header_access Date allow all
2952 request_header_access Expires allow all
2953 request_header_access Host allow all
2954 request_header_access If-Modified-Since allow all
2955 request_header_access Last-Modified allow all
2956 request_header_access Location allow all
2957 request_header_access Pragma allow all
2958 request_header_access Accept allow all
2959 request_header_access Accept-Charset allow all
2960 request_header_access Accept-Encoding allow all
2961 request_header_access Accept-Language allow all
2962 request_header_access Content-Language allow all
2963 request_header_access Mime-Version allow all
2964 request_header_access Retry-After allow all
2965 request_header_access Title allow all
2966 request_header_access Connection allow all
2967 request_header_access Proxy-Connection allow all
2968 request_header_access All deny all
2970 although many of those are HTTP reply headers, and so should be
2971 controlled with the reply_header_access directive.
2973 By default, all headers are allowed (no anonymizing is
2977 NAME: reply_header_access
2978 IFDEF: HTTP_VIOLATIONS
2979 TYPE: http_header_access[]
2980 LOC: Config.reply_header_access
2983 Usage: reply_header_access header_name allow|deny [!]aclname ...
2985 WARNING: Doing this VIOLATES the HTTP standard. Enabling
2986 this feature could make you liable for problems which it
2989 This option only applies to reply headers, i.e., from the
2990 server to the client.
2992 This is the same as request_header_access, but in the other
2995 This option replaces the old 'anonymize_headers' and the
2996 older 'http_anonymizer' option with something that is much
2997 more configurable. This new method creates a list of ACLs
2998 for each header, allowing you very fine-tuned header
3001 You can only specify known headers for the header name.
3002 Other headers are reclassified as 'Other'. You can also
3003 refer to all the headers with 'All'.
3005 For example, to achieve the same behavior as the old
3006 'http_anonymizer standard' option, you should use:
3008 reply_header_access From deny all
3009 reply_header_access Referer deny all
3010 reply_header_access Server deny all
3011 reply_header_access User-Agent deny all
3012 reply_header_access WWW-Authenticate deny all
3013 reply_header_access Link deny all
3015 Or, to reproduce the old 'http_anonymizer paranoid' feature
3018 reply_header_access Allow allow all
3019 reply_header_access Authorization allow all
3020 reply_header_access WWW-Authenticate allow all
3021 reply_header_access Proxy-Authorization allow all
3022 reply_header_access Proxy-Authenticate allow all
3023 reply_header_access Cache-Control allow all
3024 reply_header_access Content-Encoding allow all
3025 reply_header_access Content-Length allow all
3026 reply_header_access Content-Type allow all
3027 reply_header_access Date allow all
3028 reply_header_access Expires allow all
3029 reply_header_access Host allow all
3030 reply_header_access If-Modified-Since allow all
3031 reply_header_access Last-Modified allow all
3032 reply_header_access Location allow all
3033 reply_header_access Pragma allow all
3034 reply_header_access Accept allow all
3035 reply_header_access Accept-Charset allow all
3036 reply_header_access Accept-Encoding allow all
3037 reply_header_access Accept-Language allow all
3038 reply_header_access Content-Language allow all
3039 reply_header_access Mime-Version allow all
3040 reply_header_access Retry-After allow all
3041 reply_header_access Title allow all
3042 reply_header_access Connection allow all
3043 reply_header_access Proxy-Connection allow all
3044 reply_header_access All deny all
3046 although the HTTP request headers won't be usefully controlled
3047 by this directive -- see request_header_access for details.
3049 By default, all headers are allowed (no anonymizing is
3053 NAME: header_replace
3054 IFDEF: HTTP_VIOLATIONS
3055 TYPE: http_header_replace[]
3056 LOC: Config.request_header_access
3059 Usage: header_replace header_name message
3060 Example: header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
3062 This option allows you to change the contents of headers
3063 denied with header_access above, by replacing them with
3064 some fixed string. This replaces the old fake_user_agent
3067 This only applies to request headers, not reply headers.
3069 By default, headers are removed if denied.
3072 NAME: relaxed_header_parser
3073 COMMENT: on|off|warn
3075 LOC: Config.onoff.relaxed_header_parser
3078 In the default "on" setting Squid accepts certain forms
3079 of non-compliant HTTP messages where it is unambiguous
3080 what the sending application intended even if the message
3081 is not correctly formatted. The messages is then normalized
3082 to the correct form when forwarded by Squid.
3084 If set to "warn" then a warning will be emitted in cache.log
3085 each time such HTTP error is encountered.
3087 If set to "off" then such HTTP errors will cause the request
3088 or response to be rejected.
3093 -----------------------------------------------------------------------------
3096 NAME: forward_timeout
3099 LOC: Config.Timeout.forward
3102 This parameter specifies how long Squid should at most attempt in
3103 finding a forwarding path for the request before giving up.
3106 NAME: connect_timeout
3109 LOC: Config.Timeout.connect
3112 This parameter specifies how long to wait for the TCP connect to
3113 the requested server or peer to complete before Squid should
3114 attempt to find another path where to forward the request.
3117 NAME: peer_connect_timeout
3120 LOC: Config.Timeout.peer_connect
3123 This parameter specifies how long to wait for a pending TCP
3124 connection to a peer cache. The default is 30 seconds. You
3125 may also set different timeout values for individual neighbors
3126 with the 'connect-timeout' option on a 'cache_peer' line.
3132 LOC: Config.Timeout.read
3135 The read_timeout is applied on server-side connections. After
3136 each successful read(), the timeout will be extended by this
3137 amount. If no data is read again after this amount of time,
3138 the request is aborted and logged with ERR_READ_TIMEOUT. The
3139 default is 15 minutes.
3142 NAME: request_timeout
3144 LOC: Config.Timeout.request
3147 How long to wait for an HTTP request after initial
3148 connection establishment.
3151 NAME: persistent_request_timeout
3153 LOC: Config.Timeout.persistent_request
3156 How long to wait for the next HTTP request on a persistent
3157 connection after the previous request completes.
3160 NAME: client_lifetime
3163 LOC: Config.Timeout.lifetime
3166 The maximum amount of time a client (browser) is allowed to
3167 remain connected to the cache process. This protects the Cache
3168 from having a lot of sockets (and hence file descriptors) tied up
3169 in a CLOSE_WAIT state from remote clients that go away without
3170 properly shutting down (either because of a network failure or
3171 because of a poor client implementation). The default is one
3174 NOTE: The default value is intended to be much larger than any
3175 client would ever need to be connected to your cache. You
3176 should probably change client_lifetime only as a last resort.
3177 If you seem to have many client connections tying up
3178 filedescriptors, we recommend first tuning the read_timeout,
3179 request_timeout, persistent_request_timeout and quick_abort values.
3182 NAME: half_closed_clients
3184 LOC: Config.onoff.half_closed_clients
3187 Some clients may shutdown the sending side of their TCP
3188 connections, while leaving their receiving sides open. Sometimes,
3189 Squid can not tell the difference between a half-closed and a
3190 fully-closed TCP connection. By default, half-closed client
3191 connections are kept open until a read(2) or write(2) on the
3192 socket returns an error. Change this option to 'off' and Squid
3193 will immediately close client connections when read(2) returns
3194 "no more data to read."
3199 LOC: Config.Timeout.pconn
3202 Timeout for idle persistent connections to servers and other
3209 LOC: Config.Timeout.ident
3212 Maximum time to wait for IDENT lookups to complete.
3214 If this is too high, and you enabled IDENT lookups from untrusted
3215 users, you might be susceptible to denial-of-service by having
3216 many ident requests going at once.
3219 NAME: shutdown_lifetime
3222 LOC: Config.shutdownLifetime
3225 When SIGTERM or SIGHUP is received, the cache is put into
3226 "shutdown pending" mode until all active sockets are closed.
3227 This value is the lifetime to set for all open descriptors
3228 during shutdown mode. Any active clients after this many
3229 seconds will receive a 'timeout' message.
3233 ADMINISTRATIVE PARAMETERS
3234 -----------------------------------------------------------------------------
3240 LOC: Config.adminEmail
3242 Email-address of local cache manager who will receive
3243 mail if the cache dies. The default is "webmaster."
3249 LOC: Config.EmailFrom
3251 From: email-address for mail sent when the cache dies.
3252 The default is to use 'appname@unique_hostname'.
3253 Default appname value is "squid", can be changed into
3254 src/globals.h before building squid.
3260 LOC: Config.EmailProgram
3262 Email program used to send mail if the cache dies.
3263 The default is "mail". The specified program must comply
3264 with the standard Unix mail syntax:
3265 mail-program recipient < mailfile
3267 Optional command line options can be specified.
3270 NAME: cache_effective_user
3272 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
3273 LOC: Config.effectiveUser
3275 If you start Squid as root, it will change its effective/real
3276 UID/GID to the user specified below. The default is to change
3277 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
3278 see also; cache_effective_group
3281 NAME: cache_effective_group
3284 LOC: Config.effectiveGroup
3286 Squid sets the GID to the effective user's default group ID
3287 (taken from the password file) and supplementary group list
3288 from the groups membership.
3290 If you want Squid to run with a specific GID regardless of
3291 the group memberships of the effective user then set this
3292 to the group (or GID) you want Squid to run as. When set
3293 all other group privileges of the effective user are ignored
3294 and only this GID is effective. If Squid is not started as
3295 root the user starting Squid MUST be member of the specified
3298 This option is not recommended by the Squid Team.
3299 Our preference is for administrators to configure a secure
3300 user account for squid with UID/GID matching system policies.
3303 NAME: httpd_suppress_version_string
3307 LOC: Config.onoff.httpd_suppress_version_string
3309 Suppress Squid version string info in HTTP headers and HTML error pages.
3312 NAME: visible_hostname
3314 LOC: Config.visibleHostname
3317 If you want to present a special hostname in error messages, etc,
3318 define this. Otherwise, the return value of gethostname()
3319 will be used. If you have multiple caches in a cluster and
3320 get errors about IP-forwarding you must set them to have individual
3321 names with this setting.
3324 NAME: unique_hostname
3326 LOC: Config.uniqueHostname
3329 If you want to have multiple machines with the same
3330 'visible_hostname' you must give each machine a different
3331 'unique_hostname' so forwarding loops can be detected.
3334 NAME: hostname_aliases
3336 LOC: Config.hostnameAliases
3339 A list of other DNS names your cache has.
3343 OPTIONS FOR THE CACHE REGISTRATION SERVICE
3344 -----------------------------------------------------------------------------
3346 This section contains parameters for the (optional) cache
3347 announcement service. This service is provided to help
3348 cache administrators locate one another in order to join or
3349 create cache hierarchies.
3351 An 'announcement' message is sent (via UDP) to the registration
3352 service by Squid. By default, the announcement message is NOT
3353 SENT unless you enable it with 'announce_period' below.
3355 The announcement message includes your hostname, plus the
3356 following information from this configuration file:
3362 All current information is processed regularly and made
3363 available on the Web at http://www.ircache.net/Cache/Tracker/.
3366 NAME: announce_period
3368 LOC: Config.Announce.period
3371 This is how frequently to send cache announcements. The
3372 default is `0' which disables sending the announcement
3375 To enable announcing your cache, just uncomment the line
3379 #To enable announcing your cache, just uncomment the line below.
3380 #announce_period 1 day
3386 DEFAULT: tracker.ircache.net
3387 LOC: Config.Announce.host
3393 LOC: Config.Announce.file
3399 LOC: Config.Announce.port
3401 announce_host and announce_port set the hostname and port
3402 number where the registration message will be sent.
3404 Hostname will default to 'tracker.ircache.net' and port will
3405 default default to 3131. If the 'filename' argument is given,
3406 the contents of that file will be included in the announce
3411 HTTPD-ACCELERATOR OPTIONS
3412 -----------------------------------------------------------------------------
3415 NAME: httpd_accel_surrogate_id
3416 IFDEF: USE_SQUID_ESI
3418 LOC: Config.Accel.surrogate_id
3421 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
3422 need an identification token to allow control targeting. Because
3423 a farm of surrogates may all perform the same tasks, they may share
3424 an identification token.
3427 NAME: http_accel_surrogate_remote
3428 IFDEF: USE_SQUID_ESI
3432 LOC: Config.onoff.surrogate_is_remote
3434 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
3435 Set this to on to have squid behave as a remote surrogate.
3439 IFDEF: USE_SQUID_ESI
3440 COMMENT: libxml2|expat|custom
3442 LOC: ESIParser::Type
3445 ESI markup is not strictly XML compatible. The custom ESI parser
3446 will give higher performance, but cannot handle non ASCII character
3451 DELAY POOL PARAMETERS
3452 -----------------------------------------------------------------------------
3456 TYPE: delay_pool_count
3461 This represents the number of delay pools to be used. For example,
3462 if you have one class 2 delay pool and one class 3 delays pool, you
3463 have a total of 2 delay pools.
3467 TYPE: delay_pool_class
3472 This defines the class of each delay pool. There must be exactly one
3473 delay_class line for each delay pool. For example, to define two
3474 delay pools, one of class 2 and one of class 3, the settings above
3478 delay_pools 4 # 4 delay pools
3479 delay_class 1 2 # pool 1 is a class 2 pool
3480 delay_class 2 3 # pool 2 is a class 3 pool
3481 delay_class 3 4 # pool 3 is a class 4 pool
3482 delay_class 4 5 # pool 4 is a class 5 pool
3484 The delay pool classes are:
3486 class 1 Everything is limited by a single aggregate
3489 class 2 Everything is limited by a single aggregate
3490 bucket as well as an "individual" bucket chosen
3491 from bits 25 through 32 of the IP address.
3493 class 3 Everything is limited by a single aggregate
3494 bucket as well as a "network" bucket chosen
3495 from bits 17 through 24 of the IP address and a
3496 "individual" bucket chosen from bits 17 through
3497 32 of the IP address.
3499 class 4 Everything in a class 3 delay pool, with an
3500 additional limit on a per user basis. This
3501 only takes effect if the username is established
3502 in advance - by forcing authentication in your
3505 class 5 Requests are grouped according their tag (see
3506 external_acl's tag= reply).
3508 NOTE: If an IP address is a.b.c.d
3509 -> bits 25 through 32 are "d"
3510 -> bits 17 through 24 are "c"
3511 -> bits 17 through 32 are "c * 256 + d"
3515 TYPE: delay_pool_access
3520 This is used to determine which delay pool a request falls into.
3522 delay_access is sorted per pool and the matching starts with pool 1,
3523 then pool 2, ..., and finally pool N. The first delay pool where the
3524 request is allowed is selected for the request. If it does not allow
3525 the request to any pool then the request is not delayed (default).
3527 For example, if you want some_big_clients in delay
3528 pool 1 and lotsa_little_clients in delay pool 2:
3531 delay_access 1 allow some_big_clients
3532 delay_access 1 deny all
3533 delay_access 2 allow lotsa_little_clients
3534 delay_access 2 deny all
3535 delay_access 3 allow authenticated_clients
3538 NAME: delay_parameters
3539 TYPE: delay_pool_rates
3544 This defines the parameters for a delay pool. Each delay pool has
3545 a number of "buckets" associated with it, as explained in the
3546 description of delay_class. For a class 1 delay pool, the syntax is:
3548 delay_parameters pool aggregate
3550 For a class 2 delay pool:
3552 delay_parameters pool aggregate individual
3554 For a class 3 delay pool:
3556 delay_parameters pool aggregate network individual
3558 For a class 4 delay pool:
3560 delay_parameters pool aggregate network individual user
3562 For a class 5 delay pool:
3564 delay_parameters pool tag
3566 The variables here are:
3568 pool a pool number - ie, a number between 1 and the
3569 number specified in delay_pools as used in
3572 aggregate the "delay parameters" for the aggregate bucket
3575 individual the "delay parameters" for the individual
3576 buckets (class 2, 3).
3578 network the "delay parameters" for the network buckets
3581 user the delay parameters for the user buckets
3584 tag the delay parameters for the tag buckets
3587 A pair of delay parameters is written restore/maximum, where restore is
3588 the number of bytes (not bits - modem and network speeds are usually
3589 quoted in bits) per second placed into the bucket, and maximum is the
3590 maximum number of bytes which can be in the bucket at any time.
3592 For example, if delay pool number 1 is a class 2 delay pool as in the
3593 above example, and is being used to strictly limit each host to 64kbps
3594 (plus overheads), with no overall limit, the line is:
3596 delay_parameters 1 -1/-1 8000/8000
3598 Note that the figure -1 is used to represent "unlimited".
3600 And, if delay pool number 2 is a class 3 delay pool as in the above
3601 example, and you want to limit it to a total of 256kbps (strict limit)
3602 with each 8-bit network permitted 64kbps (strict limit) and each
3603 individual host permitted 4800bps with a bucket maximum size of 64kb
3604 to permit a decent web page to be downloaded at a decent speed
3605 (if the network is not being limited due to overuse) but slow down
3606 large downloads more significantly:
3608 delay_parameters 2 32000/32000 8000/8000 600/8000
3610 There must be one delay_parameters line for each delay pool.
3612 Finally, for a class 4 delay pool as in the example - each user will
3613 be limited to 128Kb no matter how many workstations they are logged into.:
3615 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
3618 NAME: delay_initial_bucket_level
3619 COMMENT: (percent, 0-100)
3623 LOC: Config.Delay.initial
3625 The initial bucket percentage is used to determine how much is put
3626 in each bucket when squid starts, is reconfigured, or first notices
3627 a host accessing it (in class 2 and class 3, individual hosts and
3628 networks only have buckets associated with them once they have been
3633 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
3634 -----------------------------------------------------------------------------
3639 LOC: Config.Wccp.router
3644 TYPE: IPAddress_list
3645 LOC: Config.Wccp2.router
3649 Use this option to define your WCCP ``home'' router for
3652 wccp_router supports a single WCCP(v1) router
3654 wccp2_router supports multiple WCCPv2 routers
3656 only one of the two may be used at the same time and defines
3657 which version of WCCP to use.
3662 LOC: Config.Wccp.version
3666 This directive is only relevant if you need to set up WCCP(v1)
3667 to some very old and end-of-life Cisco routers. In all other
3668 setups it must be left unset or at the default setting.
3669 It defines an internal version in the WCCP(v1) protocol,
3670 with version 4 being the officially documented protocol.
3672 According to some users, Cisco IOS 11.2 and earlier only
3673 support WCCP version 3. If you're using that or an earlier
3674 version of IOS, you may need to change this value to 3, otherwise
3675 do not specify this parameter.
3678 NAME: wccp2_rebuild_wait
3680 LOC: Config.Wccp2.rebuildwait
3684 If this is enabled Squid will wait for the cache dir rebuild to finish
3685 before sending the first wccp2 HereIAm packet
3688 NAME: wccp2_forwarding_method
3690 LOC: Config.Wccp2.forwarding_method
3694 WCCP2 allows the setting of forwarding methods between the
3695 router/switch and the cache. Valid values are as follows:
3697 1 - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
3698 2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
3700 Currently (as of IOS 12.4) cisco routers only support GRE.
3701 Cisco switches only support the L2 redirect assignment method.
3704 NAME: wccp2_return_method
3706 LOC: Config.Wccp2.return_method
3710 WCCP2 allows the setting of return methods between the
3711 router/switch and the cache for packets that the cache
3712 decides not to handle. Valid values are as follows:
3714 1 - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
3715 2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
3717 Currently (as of IOS 12.4) cisco routers only support GRE.
3718 Cisco switches only support the L2 redirect assignment.
3720 If the "ip wccp redirect exclude in" command has been
3721 enabled on the cache interface, then it is still safe for
3722 the proxy server to use a l2 redirect method even if this
3723 option is set to GRE.
3726 NAME: wccp2_assignment_method
3728 LOC: Config.Wccp2.assignment_method
3732 WCCP2 allows the setting of methods to assign the WCCP hash
3733 Valid values are as follows:
3738 As a general rule, cisco routers support the hash assignment method
3739 and cisco switches support the mask assignment method.
3744 LOC: Config.Wccp2.info
3746 DEFAULT_IF_NONE: standard 0
3749 WCCP2 allows for multiple traffic services. There are two
3750 types: "standard" and "dynamic". The standard type defines
3751 one service id - http (id 0). The dynamic service ids can be from
3752 51 to 255 inclusive. In order to use a dynamic service id
3753 one must define the type of traffic to be redirected; this is done
3754 using the wccp2_service_info option.
3756 The "standard" type does not require a wccp2_service_info option,
3757 just specifying the service id will suffice.
3759 MD5 service authentication can be enabled by adding
3760 "password=<password>" to the end of this service declaration.
3764 wccp2_service standard 0 # for the 'web-cache' standard service
3765 wccp2_service dynamic 80 # a dynamic service type which will be
3766 # fleshed out with subsequent options.
3767 wccp2_service standard 0 password=foo
3771 NAME: wccp2_service_info
3772 TYPE: wccp2_service_info
3773 LOC: Config.Wccp2.info
3777 Dynamic WCCPv2 services require further information to define the
3778 traffic you wish to have diverted.
3782 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
3783 priority=<priority> ports=<port>,<port>..
3785 The relevant WCCPv2 flags:
3786 + src_ip_hash, dst_ip_hash
3787 + source_port_hash, dest_port_hash
3788 + src_ip_alt_hash, dst_ip_alt_hash
3789 + src_port_alt_hash, dst_port_alt_hash
3792 The port list can be one to eight entries.
3796 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
3797 priority=240 ports=80
3799 Note: the service id must have been defined by a previous
3800 'wccp2_service dynamic <id>' entry.
3805 LOC: Config.Wccp2.weight
3809 Each cache server gets assigned a set of the destination
3810 hash proportional to their weight.
3815 LOC: Config.Wccp.address
3821 LOC: Config.Wccp2.address
3825 Use this option if you require WCCP to use a specific
3828 The default behavior is to not bind to any specific address.
3832 PERSISTENT CONNECTION HANDLING
3833 -----------------------------------------------------------------------------
3835 Also see "pconn_timeout" in the TIMEOUTS section
3838 NAME: client_persistent_connections
3840 LOC: Config.onoff.client_pconns
3844 NAME: server_persistent_connections
3846 LOC: Config.onoff.server_pconns
3849 Persistent connection support for clients and servers. By
3850 default, Squid uses persistent connections (when allowed)
3851 with its clients and servers. You can use these options to
3852 disable persistent connections with clients and/or servers.
3855 NAME: persistent_connection_after_error
3857 LOC: Config.onoff.error_pconns
3860 With this directive the use of persistent connections after
3861 HTTP errors can be disabled. Useful if you have clients
3862 who fail to handle errors on persistent connections proper.
3865 NAME: detect_broken_pconn
3867 LOC: Config.onoff.detect_broken_server_pconns
3870 Some servers have been found to incorrectly signal the use
3871 of HTTP/1.0 persistent connections even on replies not
3872 compatible, causing significant delays. This server problem
3873 has mostly been seen on redirects.
3875 By enabling this directive Squid attempts to detect such
3876 broken replies and automatically assume the reply is finished
3877 after 10 seconds timeout.
3881 CACHE DIGEST OPTIONS
3882 -----------------------------------------------------------------------------
3885 NAME: digest_generation
3886 IFDEF: USE_CACHE_DIGESTS
3888 LOC: Config.onoff.digest_generation
3891 This controls whether the server will generate a Cache Digest
3892 of its contents. By default, Cache Digest generation is
3893 enabled if Squid is compiled with --enable-cache-digests defined.
3896 NAME: digest_bits_per_entry
3897 IFDEF: USE_CACHE_DIGESTS
3899 LOC: Config.digest.bits_per_entry
3902 This is the number of bits of the server's Cache Digest which
3903 will be associated with the Digest entry for a given HTTP
3904 Method and URL (public key) combination. The default is 5.
3907 NAME: digest_rebuild_period
3908 IFDEF: USE_CACHE_DIGESTS
3911 LOC: Config.digest.rebuild_period
3914 This is the wait time between Cache Digest rebuilds.
3917 NAME: digest_rewrite_period
3919 IFDEF: USE_CACHE_DIGESTS
3921 LOC: Config.digest.rewrite_period
3924 This is the wait time between Cache Digest writes to
3928 NAME: digest_swapout_chunk_size
3931 IFDEF: USE_CACHE_DIGESTS
3932 LOC: Config.digest.swapout_chunk_size
3935 This is the number of bytes of the Cache Digest to write to
3936 disk at a time. It defaults to 4096 bytes (4KB), the Squid
3940 NAME: digest_rebuild_chunk_percentage
3941 COMMENT: (percent, 0-100)
3942 IFDEF: USE_CACHE_DIGESTS
3944 LOC: Config.digest.rebuild_chunk_percentage
3947 This is the percentage of the Cache Digest to be scanned at a
3948 time. By default it is set to 10% of the Cache Digest.
3953 -----------------------------------------------------------------------------
3958 LOC: Config.Port.snmp
3962 The port number where Squid listens for SNMP requests. To enable
3963 SNMP support set this to a suitable port number. Port number
3964 3401 is often used for the Squid SNMP agent. By default it's
3965 set to "0" (disabled)
3973 LOC: Config.accessList.snmp
3975 DEFAULT_IF_NONE: deny all
3978 Allowing or denying access to the SNMP port.
3980 All access to the agent is denied by default.
3983 snmp_access allow|deny [!]aclname ...
3986 snmp_access allow snmppublic localhost
3987 snmp_access deny all
3990 NAME: snmp_incoming_address
3992 LOC: Config.Addrs.snmp_incoming
3996 NAME: snmp_outgoing_address
3998 LOC: Config.Addrs.snmp_outgoing
3999 DEFAULT: 255.255.255.255
4002 Just like 'udp_incoming_address' above, but for the SNMP port.
4004 snmp_incoming_address is used for the SNMP socket receiving
4005 messages from SNMP agents.
4006 snmp_outgoing_address is used for SNMP packets returned to SNMP
4009 The default snmp_incoming_address (0.0.0.0) is to listen on all
4010 available network interfaces.
4012 If snmp_outgoing_address is set to 255.255.255.255 (the default)
4013 it will use the same socket as snmp_incoming_address. Only
4014 change this if you want to have SNMP replies sent using another
4015 address than where this Squid listens for SNMP queries.
4017 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
4018 the same value since they both use port 3401.
4023 -----------------------------------------------------------------------------
4026 NAME: icp_port udp_port
4029 LOC: Config.Port.icp
4031 The port number where Squid sends and receives ICP queries to
4032 and from neighbor caches. The standard UDP port for ICP is 3130.
4033 Default is disabled (0).
4035 icp_port @DEFAULT_ICP_PORT@
4043 LOC: Config.Port.htcp
4045 The port number where Squid sends and receives HTCP queries to
4046 and from neighbor caches. To turn it on you want to set it to
4047 4827. By default it is set to "0" (disabled).
4053 NAME: log_icp_queries
4057 LOC: Config.onoff.log_udp
4059 If set, ICP queries are logged to access.log. You may wish
4060 do disable this if your ICP load is VERY high to speed things
4061 up or to simplify log analysis.
4064 NAME: udp_incoming_address
4066 LOC:Config.Addrs.udp_incoming
4069 udp_incoming_address is used for UDP packets received from other
4072 The default behavior is to not bind to any specific address.
4074 Only change this if you want to have all UDP queries received on
4075 a specific interface/address.
4077 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
4078 modules. Altering it will affect all of them in the same manner.
4080 see also; udp_outgoing_address
4082 NOTE, udp_incoming_address and udp_outgoing_address can not
4083 have the same value since they both use the same port.
4086 NAME: udp_outgoing_address
4088 LOC: Config.Addrs.udp_outgoing
4089 DEFAULT: 255.255.255.255
4091 udp_outgoing_address is used for UDP packets sent out to other
4094 The default behavior is to not bind to any specific address.
4096 Instead it will use the same socket as udp_incoming_address.
4097 Only change this if you want to have UDP queries sent using another
4098 address than where this Squid listens for UDP queries from other
4101 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
4102 modules. Altering it will affect all of them in the same manner.
4104 see also; udp_incoming_address
4106 NOTE, udp_incoming_address and udp_outgoing_address can not
4107 have the same value since they both use the same port.
4114 LOC: Config.onoff.icp_hit_stale
4116 If you want to return ICP_HIT for stale cache objects, set this
4117 option to 'on'. If you have sibling relationships with caches
4118 in other administrative domains, this should be 'off'. If you only
4119 have sibling relationships with caches under your control,
4120 it is probably okay to set this to 'on'.
4121 If set to 'on', your siblings should use the option "allow-miss"
4122 on their cache_peer lines for connecting to you.
4125 NAME: minimum_direct_hops
4128 LOC: Config.minDirectHops
4130 If using the ICMP pinging stuff, do direct fetches for sites
4131 which are no more than this many hops away.
4134 NAME: minimum_direct_rtt
4137 LOC: Config.minDirectRtt
4139 If using the ICMP pinging stuff, do direct fetches for sites
4140 which are no more than this many rtt milliseconds away.
4146 LOC: Config.Netdb.low
4152 LOC: Config.Netdb.high
4154 The low and high water marks for the ICMP measurement
4155 database. These are counts, not percents. The defaults are
4156 900 and 1000. When the high water mark is reached, database
4157 entries will be deleted until the low mark is reached.
4160 NAME: netdb_ping_period
4162 LOC: Config.Netdb.period
4165 The minimum period for measuring a site. There will be at
4166 least this much delay between successive pings to the same
4167 network. The default is five minutes.
4174 LOC: Config.onoff.query_icmp
4176 If you want to ask your peers to include ICMP data in their ICP
4177 replies, enable this option.
4179 If your peer has configured Squid (during compilation) with
4180 '--enable-icmp' that peer will send ICMP pings to origin server
4181 sites of the URLs it receives. If you enable this option the
4182 ICP replies from that peer will include the ICMP data (if available).
4183 Then, when choosing a parent cache, Squid will choose the parent with
4184 the minimal RTT to the origin server. When this happens, the
4185 hierarchy field of the access.log will be
4186 "CLOSEST_PARENT_MISS". This option is off by default.
4189 NAME: test_reachability
4193 LOC: Config.onoff.test_reachability
4195 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
4196 instead of ICP_MISS if the target host is NOT in the ICMP
4197 database, or has a zero RTT.
4200 NAME: icp_query_timeout
4204 LOC: Config.Timeout.icp_query
4206 Normally Squid will automatically determine an optimal ICP
4207 query timeout value based on the round-trip-time of recent ICP
4208 queries. If you want to override the value determined by
4209 Squid, set this 'icp_query_timeout' to a non-zero value. This
4210 value is specified in MILLISECONDS, so, to use a 2-second
4211 timeout (the old default), you would write:
4213 icp_query_timeout 2000
4216 NAME: maximum_icp_query_timeout
4220 LOC: Config.Timeout.icp_query_max
4222 Normally the ICP query timeout is determined dynamically. But
4223 sometimes it can lead to very large values (say 5 seconds).
4224 Use this option to put an upper limit on the dynamic timeout
4225 value. Do NOT use this option to always use a fixed (instead
4226 of a dynamic) timeout value. To set a fixed timeout see the
4227 'icp_query_timeout' directive.
4230 NAME: minimum_icp_query_timeout
4234 LOC: Config.Timeout.icp_query_min
4236 Normally the ICP query timeout is determined dynamically. But
4237 sometimes it can lead to very small timeouts, even lower than
4238 the normal latency variance on your link due to traffic.
4239 Use this option to put an lower limit on the dynamic timeout
4240 value. Do NOT use this option to always use a fixed (instead
4241 of a dynamic) timeout value. To set a fixed timeout see the
4242 'icp_query_timeout' directive.
4245 NAME: background_ping_rate
4249 LOC: Config.backgroundPingRate
4251 Controls how often the ICP pings are sent to siblings that
4252 have background-ping set.
4256 MULTICAST ICP OPTIONS
4257 -----------------------------------------------------------------------------
4262 LOC: Config.mcast_group_list
4265 This tag specifies a list of multicast groups which your server
4266 should join to receive multicasted ICP queries.
4268 NOTE! Be very careful what you put here! Be sure you
4269 understand the difference between an ICP _query_ and an ICP
4270 _reply_. This option is to be set only if you want to RECEIVE
4271 multicast queries. Do NOT set this option to SEND multicast
4272 ICP (use cache_peer for that). ICP replies are always sent via
4273 unicast, so this option does not affect whether or not you will
4274 receive replies from multicast group members.
4276 You must be very careful to NOT use a multicast address which
4277 is already in use by another group of caches.
4279 If you are unsure about multicast, please read the Multicast
4280 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
4282 Usage: mcast_groups 239.128.16.128 224.0.1.20
4284 By default, Squid doesn't listen on any multicast groups.
4287 NAME: mcast_miss_addr
4288 IFDEF: MULTICAST_MISS_STREAM
4290 LOC: Config.mcast_miss.addr
4291 DEFAULT: 255.255.255.255
4293 If you enable this option, every "cache miss" URL will
4294 be sent out on the specified multicast address.
4296 Do not enable this option unless you are are absolutely
4297 certain you understand what you are doing.
4300 NAME: mcast_miss_ttl
4301 IFDEF: MULTICAST_MISS_STREAM
4303 LOC: Config.mcast_miss.ttl
4306 This is the time-to-live value for packets multicasted
4307 when multicasting off cache miss URLs is enabled. By
4308 default this is set to 'site scope', i.e. 16.
4311 NAME: mcast_miss_port
4312 IFDEF: MULTICAST_MISS_STREAM
4314 LOC: Config.mcast_miss.port
4317 This is the port number to be used in conjunction with
4321 NAME: mcast_miss_encode_key
4322 IFDEF: MULTICAST_MISS_STREAM
4324 LOC: Config.mcast_miss.encode_key
4325 DEFAULT: XXXXXXXXXXXXXXXX
4327 The URLs that are sent in the multicast miss stream are
4328 encrypted. This is the encryption key.
4331 NAME: mcast_icp_query_timeout
4335 LOC: Config.Timeout.mcast_icp_query
4337 For multicast peers, Squid regularly sends out ICP "probes" to
4338 count how many other peers are listening on the given multicast
4339 address. This value specifies how long Squid should wait to
4340 count all the replies. The default is 2000 msec, or 2
4345 INTERNAL ICON OPTIONS
4346 -----------------------------------------------------------------------------
4349 NAME: icon_directory
4351 LOC: Config.icons.directory
4352 DEFAULT: @DEFAULT_ICON_DIR@
4354 Where the icons are stored. These are normally kept in
4358 NAME: global_internal_static
4360 LOC: Config.onoff.global_internal_static
4363 This directive controls is Squid should intercept all requests for
4364 /squid-internal-static/ no matter which host the URL is requesting
4365 (default on setting), or if nothing special should be done for
4366 such URLs (off setting). The purpose of this directive is to make
4367 icons etc work better in complex cache hierarchies where it may
4368 not always be possible for all corners in the cache mesh to reach
4369 the server generating a directory listing.
4372 NAME: short_icon_urls
4374 LOC: Config.icons.use_short_names
4377 If this is enabled Squid will use short URLs for icons.
4378 If disabled it will revert to the old behavior of including
4379 it's own name and port in the URL.
4381 If you run a complex cache hierarchy with a mix of Squid and
4382 other proxies you may need to disable this directive.
4387 -----------------------------------------------------------------------------
4390 NAME: error_directory
4392 LOC: Config.errorDirectory
4393 DEFAULT: @DEFAULT_ERROR_DIR@
4395 If you wish to create your own versions of the default
4396 (English) error files, either to customize them to suit your
4397 language or company copy the template English files to another
4398 directory and point this tag at them.
4400 The squid developers are interested in making squid available in
4401 a wide variety of languages. If you are making translations for a
4402 langauge that Squid does not currently provide please consider
4403 contributing your translation back to the project.
4408 LOC: Config.errHtmlText
4411 HTML text to include in error messages. Make this a "mailto"
4412 URL to your admin address, or maybe just a link to your
4413 organizations Web page.
4415 To include this in your error messages, you must rewrite
4416 the error template files (found in the "errors" directory).
4417 Wherever you want the 'err_html_text' line to appear,
4418 insert a %L tag in the error template file.
4421 NAME: email_err_data
4424 LOC: Config.onoff.emailErrData
4427 If enabled, information about the occurred error will be
4428 included in the mailto links of the ERR pages (if %W is set)
4429 so that the email body contains the data.
4430 Syntax is <A HREF="mailto:%w%W">%w</A>
4435 LOC: Config.denyInfoList
4438 Usage: deny_info err_page_name acl
4439 or deny_info http://... acl
4440 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
4442 This can be used to return a ERR_ page for requests which
4443 do not pass the 'http_access' rules. Squid remembers the last
4444 acl it evaluated in http_access, and if a 'deny_info' line exists
4445 for that ACL Squid returns a corresponding error page.
4447 The acl is typically the last acl on the http_access deny line which
4448 denied access. The exceptions to this rule are:
4449 - When Squid needs to request authentication credentials. It's then
4450 the first authentication related acl encountered
4451 - When none of the http_access lines matches. It's then the last
4452 acl processed on the last http_access line.
4454 You may use ERR_ pages that come with Squid or create your own pages
4455 and put them into the configured errors/ directory.
4457 Alternatively you can specify an error URL. The browsers will
4458 get redirected (302) to the specified URL. %s in the redirection
4459 URL will be replaced by the requested URL.
4461 Alternatively you can tell Squid to reset the TCP connection
4462 by specifying TCP_RESET.
4466 OPTIONS INFLUENCING REQUEST FORWARDING
4467 -----------------------------------------------------------------------------
4470 NAME: nonhierarchical_direct
4472 LOC: Config.onoff.nonhierarchical_direct
4475 By default, Squid will send any non-hierarchical requests
4476 (matching hierarchy_stoplist or not cacheable request type) direct
4479 If you set this to off, Squid will prefer to send these
4480 requests to parents.
4482 Note that in most configurations, by turning this off you will only
4483 add latency to these request without any improvement in global hit
4486 If you are inside an firewall see never_direct instead of
4492 LOC: Config.onoff.prefer_direct
4495 Normally Squid tries to use parents for most requests. If you for some
4496 reason like it to first try going direct and only use a parent if
4497 going direct fails set this to on.
4499 By combining nonhierarchical_direct off and prefer_direct on you
4500 can set up Squid to use a parent as a backup path if going direct
4503 Note: If you want Squid to use parents for all requests see
4504 the never_direct directive. prefer_direct only modifies how Squid
4505 acts on cacheable requests.
4510 LOC: Config.accessList.AlwaysDirect
4513 Usage: always_direct allow|deny [!]aclname ...
4515 Here you can use ACL elements to specify requests which should
4516 ALWAYS be forwarded by Squid to the origin servers without using
4517 any peers. For example, to always directly forward requests for
4518 local servers ignoring any parents or siblings you may have use
4521 acl local-servers dstdomain my.domain.net
4522 always_direct allow local-servers
4524 To always forward FTP requests directly, use
4527 always_direct allow FTP
4529 NOTE: There is a similar, but opposite option named
4530 'never_direct'. You need to be aware that "always_direct deny
4531 foo" is NOT the same thing as "never_direct allow foo". You
4532 may need to use a deny rule to exclude a more-specific case of
4533 some other rule. Example:
4535 acl local-external dstdomain external.foo.net
4536 acl local-servers dstdomain .foo.net
4537 always_direct deny local-external
4538 always_direct allow local-servers
4540 NOTE: If your goal is to make the client forward the request
4541 directly to the origin server bypassing Squid then this needs
4542 to be done in the client configuration. Squid configuration
4543 can only tell Squid how Squid should fetch the object.
4545 NOTE: This directive is not related to caching. The replies
4546 is cached as usual even if you use always_direct. To not cache
4547 the replies see no_cache.
4549 This option replaces some v1.1 options such as local_domain
4555 LOC: Config.accessList.NeverDirect
4558 Usage: never_direct allow|deny [!]aclname ...
4560 never_direct is the opposite of always_direct. Please read
4561 the description for always_direct if you have not already.
4563 With 'never_direct' you can use ACL elements to specify
4564 requests which should NEVER be forwarded directly to origin
4565 servers. For example, to force the use of a proxy for all
4566 requests, except those in your local domain use something like:
4568 acl local-servers dstdomain .foo.net
4569 acl all src 0.0.0.0/0.0.0.0
4570 never_direct deny local-servers
4571 never_direct allow all
4573 or if Squid is inside a firewall and there are local intranet
4574 servers inside the firewall use something like:
4576 acl local-intranet dstdomain .foo.net
4577 acl local-external dstdomain external.foo.net
4578 always_direct deny local-external
4579 always_direct allow local-intranet
4580 never_direct allow all
4582 This option replaces some v1.1 options such as inside_firewall
4587 ADVANCED NETWORKING OPTIONS
4588 -----------------------------------------------------------------------------
4591 NAME: incoming_icp_average
4594 LOC: Config.comm_incoming.icp_average
4597 NAME: incoming_http_average
4600 LOC: Config.comm_incoming.http_average
4603 NAME: incoming_dns_average
4606 LOC: Config.comm_incoming.dns_average
4609 NAME: min_icp_poll_cnt
4612 LOC: Config.comm_incoming.icp_min_poll
4615 NAME: min_dns_poll_cnt
4618 LOC: Config.comm_incoming.dns_min_poll
4621 NAME: min_http_poll_cnt
4624 LOC: Config.comm_incoming.http_min_poll
4626 Heavy voodoo here. I can't even believe you are reading this.
4627 Are you crazy? Don't even think about adjusting these unless
4628 you understand the algorithms in comm_select.c first!
4634 LOC: Config.accept_filter
4638 The name of an accept(2) filter to install on Squid's
4639 listen socket(s). This feature is perhaps specific to
4640 FreeBSD and requires support in the kernel.
4642 The 'httpready' filter delays delivering new connections
4643 to Squid until a full HTTP request has been received.
4644 See the accf_http(9) man page for details.
4646 The 'dataready' filter delays delivering new connections
4647 to Squid until there is some data to process.
4648 See the accf_dataready(9) man page for details.
4652 The 'data' filter delays delivering of new connections
4653 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
4654 You may optionally specify a number of seconds to wait by
4655 'data=N' where N is the number of seconds. Defaults to 30
4656 if not specified. See the tcp(7) man page for details.
4659 accept_filter httpready
4664 NAME: tcp_recv_bufsize
4668 LOC: Config.tcpRcvBufsz
4670 Size of receive buffer to set for TCP sockets. Probably just
4671 as easy to change your kernel's default. Set to zero to use
4672 the default buffer size.
4677 -----------------------------------------------------------------------------
4684 LOC: TheICAPConfig.onoff
4687 If you want to enable the ICAP module support, set this to on.
4690 NAME: icap_connect_timeout
4693 LOC: TheICAPConfig.connect_timeout_raw
4696 This parameter specifies how long to wait for the TCP connect to
4697 the requested ICAP server to complete before giving up and either
4698 terminating the HTTP transaction or bypassing the failure.
4700 The default for optional services is peer_connect_timeout.
4701 The default for essential services is connect_timeout.
4702 If this option is explicitly set, its value applies to all services.
4705 NAME: icap_io_timeout
4709 LOC: TheICAPConfig.io_timeout_raw
4712 This parameter specifies how long to wait for an I/O activity on
4713 an established, active ICAP connection before giving up and
4714 either terminating the HTTP transaction or bypassing the
4717 The default is read_timeout.
4720 NAME: icap_service_failure_limit
4723 LOC: TheICAPConfig.service_failure_limit
4726 The limit specifies the number of failures that Squid tolerates
4727 when establishing a new TCP connection with an ICAP service. If
4728 the number of failures exceeds the limit, the ICAP service is
4729 not used for new ICAP requests until it is time to refresh its
4730 OPTIONS. The per-service failure counter is reset to zero each
4731 time Squid fetches new service OPTIONS.
4733 A negative value disables the limit. Without the limit, an ICAP
4734 service will not be considered down due to connectivity failures
4735 between ICAP OPTIONS requests.
4738 NAME: icap_service_revival_delay
4741 LOC: TheICAPConfig.service_revival_delay
4744 The delay specifies the number of seconds to wait after an ICAP
4745 OPTIONS request failure before requesting the options again. The
4746 failed ICAP service is considered "down" until fresh OPTIONS are
4749 The actual delay cannot be smaller than the hardcoded minimum
4750 delay of 30 seconds.
4753 NAME: icap_preview_enable
4757 LOC: TheICAPConfig.preview_enable
4760 The ICAP Preview feature allows the ICAP server to handle the
4761 HTTP message by looking only at the beginning of the message body
4762 or even without receiving the body at all. In some environments,
4763 previews greatly speedup ICAP processing.
4765 During an ICAP OPTIONS transaction, the server may tell Squid what
4766 HTTP messages should be previewed and how big the preview should be.
4767 Squid will not use Preview if the server did not request one.
4769 To disable ICAP Preview for all ICAP services, regardless of
4770 individual ICAP server OPTIONS responses, set this option to "off".
4772 icap_preview_enable off
4775 NAME: icap_preview_size
4778 LOC: TheICAPConfig.preview_size
4781 The default size of preview data to be sent to the ICAP server.
4782 -1 means no preview. This value might be overwritten on a per server
4783 basis by OPTIONS requests.
4786 NAME: icap_default_options_ttl
4789 LOC: TheICAPConfig.default_options_ttl
4792 The default TTL value for ICAP OPTIONS responses that don't have
4793 an Options-TTL header.
4796 NAME: icap_persistent_connections
4800 LOC: TheICAPConfig.reuse_connections
4803 Whether or not Squid should use persistent connections to
4807 NAME: icap_send_client_ip
4811 LOC: TheICAPConfig.send_client_ip
4814 This adds the header "X-Client-IP" to ICAP requests.
4817 NAME: icap_send_client_username
4821 LOC: TheICAPConfig.send_client_username
4824 This sends authenticated HTTP client username (if available) to
4825 the ICAP service. The username value is encoded based on the
4826 icap_client_username_encode option and is sent using the header
4827 specified by the icap_client_username_header option.
4830 NAME: icap_client_username_header
4833 LOC: TheICAPConfig.client_username_header
4834 DEFAULT: X-Client-Username
4836 ICAP request header name to use for send_client_username.
4839 NAME: icap_client_username_encode
4843 LOC: TheICAPConfig.client_username_encode
4846 Whether to base64 encode the authenticated client username.
4850 TYPE: icap_service_type
4855 Defines a single ICAP service
4857 icap_service servicename vectoring_point bypass service_url
4859 vectoring_point = reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
4860 This specifies at which point of transaction processing the
4861 ICAP service should be activated. *_postcache vectoring points
4862 are not yet supported.
4864 If set to 1, the ICAP service is treated as optional. If the
4865 service cannot be reached or malfunctions, Squid will try to
4866 ignore any errors and process the message as if the service
4867 was not enabled. No all ICAP errors can be bypassed.
4868 If set to 0, the ICAP service is treated as essential and all
4869 ICAP errors will result in an error page returned to the
4871 service_url = icap://servername:port/service
4874 icap_service service_1 reqmod_precache 0 icap://icap1.mydomain.net:1344/reqmod
4875 icap_service service_2 respmod_precache 0 icap://icap2.mydomain.net:1344/respmod
4879 TYPE: icap_class_type
4884 Defines an ICAP service chain. Eventually, multiple services per
4885 vectoring point will be supported. For now, please specify a single
4888 icap_class classname servicename
4891 icap_class class_1 service_1
4892 icap class class_2 service_1
4893 icap class class_3 service_3
4897 TYPE: icap_access_type
4902 Redirects a request through an ICAP service class, depending
4905 icap_access classname allow|deny [!]aclname...
4907 The icap_access statements are processed in the order they appear in
4908 this configuration file. If an access list matches, the processing stops.
4909 For an "allow" rule, the specified class is used for the request. A "deny"
4910 rule simply stops processing without using the class. You can also use the
4911 special classname "None".
4913 For backward compatibility, it is also possible to use services
4916 icap_access class_1 allow all
4921 -----------------------------------------------------------------------------
4924 NAME: check_hostnames
4927 LOC: Config.onoff.check_hostnames
4929 For security and stability reasons Squid can check
4930 hostnames for Internet standard RFC compliance. If you want
4931 Squid to perform these checks turn this directive on.
4934 NAME: allow_underscore
4937 LOC: Config.onoff.allow_underscore
4939 Underscore characters is not strictly allowed in Internet hostnames
4940 but nevertheless used by many sites. Set this to off if you want
4941 Squid to be strict about the standard.
4942 This check is performed only when check_hostnames is set to on.
4945 NAME: cache_dns_program
4947 IFDEF: USE_DNSSERVERS
4948 DEFAULT: @DEFAULT_DNSSERVER@
4949 LOC: Config.Program.dnsserver
4951 Specify the location of the executable for dnslookup process.
4956 IFDEF: USE_DNSSERVERS
4958 LOC: Config.dnsChildren
4960 The number of processes spawn to service DNS name lookups.
4961 For heavily loaded caches on large servers, you should
4962 probably increase this value to at least 10. The maximum
4963 is 32. The default is 5.
4965 You must have at least one dnsserver process.
4968 NAME: dns_retransmit_interval
4971 LOC: Config.Timeout.idns_retransmit
4972 IFDEF: !USE_DNSSERVERS
4974 Initial retransmit interval for DNS queries. The interval is
4975 doubled each time all configured DNS servers have been tried.
4982 LOC: Config.Timeout.idns_query
4983 IFDEF: !USE_DNSSERVERS
4985 DNS Query timeout. If no response is received to a DNS query
4986 within this time all DNS servers for the queried domain
4987 are assumed to be unavailable.
4994 LOC: Config.onoff.res_defnames
4996 Normally the RES_DEFNAMES resolver option is disabled
4997 (see res_init(3)). This prevents caches in a hierarchy
4998 from interpreting single-component hostnames locally. To allow
4999 Squid to handle single-component names, enable this option.
5002 NAME: dns_nameservers
5005 LOC: Config.dns_nameservers
5007 Use this if you want to specify a list of DNS name servers
5008 (IP addresses) to use instead of those given in your
5009 /etc/resolv.conf file.
5010 On Windows platforms, if no value is specified here or in
5011 the /etc/resolv.conf file, the list of DNS name servers are
5012 taken from the Windows registry, both static and dynamic DHCP
5013 configurations are supported.
5015 Example: dns_nameservers 10.0.0.1 192.172.0.4
5020 DEFAULT: @DEFAULT_HOSTS@
5021 LOC: Config.etcHostsPath
5023 Location of the host-local IP name-address associations
5024 database. Most Operating Systems have such a file on different
5026 - Un*X & Linux: /etc/hosts
5027 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
5028 (%SystemRoot% value install default is c:\winnt)
5029 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
5030 (%SystemRoot% value install default is c:\windows)
5031 - Windows 9x/Me: %windir%\hosts
5032 (%windir% value is usually c:\windows)
5033 - Cygwin: /etc/hosts
5035 The file contains newline-separated definitions, in the
5036 form ip_address_in_dotted_form name [name ...] names are
5037 whitespace-separated. Lines beginning with an hash (#)
5038 character are comments.
5040 The file is checked at startup and upon configuration.
5041 If set to 'none', it won't be checked.
5042 If append_domain is used, that domain will be added to
5043 domain-local (i.e. not containing any dot character) host
5049 LOC: Config.dns_testname_list
5051 DEFAULT_IF_NONE: netscape.com internic.net nlanr.net microsoft.com
5053 The DNS tests exit as soon as the first site is successfully looked up
5055 This test can be disabled with the -D command line option.
5060 LOC: Config.appendDomain
5063 Appends local domain name to hostnames without any dots in
5064 them. append_domain must begin with a period.
5066 Be warned there are now Internet names with no dots in
5067 them using only top-domain names, so setting this may
5068 cause some Internet sites to become unavailable.
5071 append_domain .yourdomain.com
5074 NAME: ignore_unknown_nameservers
5076 LOC: Config.onoff.ignore_unknown_nameservers
5079 By default Squid checks that DNS responses are received
5080 from the same IP addresses they are sent to. If they
5081 don't match, Squid ignores the response and writes a warning
5082 message to cache.log. You can allow responses from unknown
5083 nameservers by setting this option to 'off'.
5086 NAME: dns_v4_fallback
5089 LOC: Config.onoff.dns_require_A
5091 Standard practice with DNS is to lookup either A or AAAA records
5092 and use the results if it succeeds. Only looking up the other if
5093 the first attempt fails or otherwise produces no results.
5095 That policy however will cause squid to produce error pages for some
5096 servers that advertise AAAA but are unreachable over IPv6.
5098 If this is ON squid will always lookup both AAAA and A, using both.
5099 If this is OFF squid will lookup AAAA and only try A if none found.
5101 WARNING: There are some possibly unwanted side-effects with this on:
5102 *) Doubles the load placed by squid on the DNS network.
5103 *) May negatively impact connection delay times.
5107 COMMENT: (number of entries)
5110 LOC: Config.ipcache.size
5117 LOC: Config.ipcache.low
5124 LOC: Config.ipcache.high
5126 The size, low-, and high-water marks for the IP cache.
5129 NAME: fqdncache_size
5130 COMMENT: (number of entries)
5133 LOC: Config.fqdncache.size
5135 Maximum number of FQDN cache entries.
5140 -----------------------------------------------------------------------------
5147 LOC: Config.onoff.mem_pools
5149 If set, Squid will keep pools of allocated (but unused) memory
5150 available for future use. If memory is a premium on your
5151 system and you believe your malloc library outperforms Squid
5152 routines, disable this.
5155 NAME: memory_pools_limit
5159 LOC: Config.MemPools.limit
5161 Used only with memory_pools on:
5162 memory_pools_limit 50 MB
5164 If set to a non-zero value, Squid will keep at most the specified
5165 limit of allocated (but unused) memory in memory pools. All free()
5166 requests that exceed this limit will be handled by your malloc
5167 library. Squid does not pre-allocate any memory, just safe-keeps
5168 objects that otherwise would be free()d. Thus, it is safe to set
5169 memory_pools_limit to a reasonably high value even if your
5170 configuration will use less memory.
5172 If set to zero, Squid will keep all memory it can. That is, there
5173 will be no limit on the total amount of memory used for safe-keeping.
5175 To disable memory allocation optimization, do not set
5176 memory_pools_limit to 0. Set memory_pools to "off" instead.
5178 An overhead for maintaining memory pools is not taken into account
5179 when the limit is checked. This overhead is close to four bytes per
5180 object kept. However, pools may actually _save_ memory because of
5181 reduced memory thrashing in your malloc library.
5188 LOC: opt_forwarded_for
5190 If set, Squid will include your system's IP address or name
5191 in the HTTP requests it forwards. By default it looks like
5194 X-Forwarded-For: 192.1.2.3
5196 If you disable this, it will appear as
5198 X-Forwarded-For: unknown
5201 NAME: cachemgr_passwd
5202 TYPE: cachemgrpasswd
5204 LOC: Config.passwd_list
5206 Specify passwords for cachemgr operations.
5208 Usage: cachemgr_passwd password action action ...
5210 Some valid actions are (see cache manager menu for a full list):
5249 * Indicates actions which will not be performed without a
5250 valid password, others can be performed if not listed here.
5252 To disable an action, set the password to "disable".
5253 To allow performing an action without a password, set the
5256 Use the keyword "all" to set the same password for all actions.
5259 cachemgr_passwd secret shutdown
5260 cachemgr_passwd lesssssssecret info stats/objects
5261 cachemgr_passwd disable all
5268 LOC: Config.onoff.client_db
5270 If you want to disable collecting per-client statistics,
5271 turn off client_db here.
5274 NAME: refresh_all_ims
5278 LOC: Config.onoff.refresh_all_ims
5280 When you enable this option, squid will always check
5281 the origin server for an update when a client sends an
5282 If-Modified-Since request. Many browsers use IMS
5283 requests when the user requests a reload, and this
5284 ensures those clients receive the latest version.
5286 By default (off), squid may return a Not Modified response
5287 based on the age of the cached version.
5290 NAME: reload_into_ims
5291 IFDEF: HTTP_VIOLATIONS
5295 LOC: Config.onoff.reload_into_ims
5297 When you enable this option, client no-cache or ``reload''
5298 requests will be changed to If-Modified-Since requests.
5299 Doing this VIOLATES the HTTP standard. Enabling this
5300 feature could make you liable for problems which it
5303 see also refresh_pattern for a more selective approach.
5306 NAME: maximum_single_addr_tries
5308 LOC: Config.retry.maxtries
5311 This sets the maximum number of connection attempts for a
5312 host that only has one address (for multiple-address hosts,
5313 each address is tried once).
5315 The default value is one attempt, the (not recommended)
5316 maximum is 255 tries. A warning message will be generated
5317 if it is set to a value greater than ten.
5319 Note: This is in addition to the request re-forwarding which
5320 takes place if Squid fails to get a satisfying response.
5323 NAME: retry_on_error
5325 LOC: Config.retry.onerror
5328 If set to on Squid will automatically retry requests when
5329 receiving an error response. This is mainly useful if you
5330 are in a complex cache hierarchy to work around access
5334 NAME: as_whois_server
5336 LOC: Config.as_whois_server
5337 DEFAULT: whois.ra.net
5338 DEFAULT_IF_NONE: whois.ra.net
5340 WHOIS server to query for AS numbers. NOTE: AS numbers are
5341 queried only when Squid starts up, not for every request.
5346 LOC: Config.onoff.offline
5349 Enable this option and Squid will never try to validate cached
5353 NAME: uri_whitespace
5354 TYPE: uri_whitespace
5355 LOC: Config.uri_whitespace
5358 What to do with requests that have whitespace characters in the
5361 strip: The whitespace characters are stripped out of the URL.
5362 This is the behavior recommended by RFC2396.
5363 deny: The request is denied. The user receives an "Invalid
5365 allow: The request is allowed and the URI is not changed. The
5366 whitespace characters remain in the URI. Note the
5367 whitespace is passed to redirector processes if they
5369 encode: The request is allowed and the whitespace characters are
5370 encoded according to RFC1738. This could be considered
5371 a violation of the HTTP/1.1
5372 RFC because proxies are not allowed to rewrite URI's.
5373 chop: The request is allowed and the URI is chopped at the
5374 first whitespace. This might also be considered a
5380 LOC: Config.coredump_dir
5382 DEFAULT_IF_NONE: none
5384 By default Squid leaves core files in the directory from where
5385 it was started. If you set 'coredump_dir' to a directory
5386 that exists, Squid will chdir() to that directory at startup
5387 and coredump files will be left there.
5390 # Leave coredumps in the first cache dir
5391 coredump_dir @DEFAULT_SWAP_DIR@
5397 LOC: Config.chroot_dir
5400 Use this to have Squid do a chroot() while initializing. This
5401 also causes Squid to fully drop root privileges after
5402 initializing. This means, for example, if you use a HTTP
5403 port less than 1024 and try to reconfigure, you will may get an
5404 error saying that Squid can not open the port.
5407 NAME: balance_on_multiple_ip
5409 LOC: Config.onoff.balance_on_multiple_ip
5412 Modern IP resolvers in squid sort lookup results by preferred access.
5413 By default squid will use these IP in order and only rotates to
5414 the next listed when the most preffered fails.
5416 Some load balancing servers based on round robin DNS have been
5417 found not to preserve user session state across requests
5418 to different IP addresses.
5420 Enabling this directive Squid rotates IP's per request.
5423 NAME: pipeline_prefetch
5425 LOC: Config.onoff.pipeline_prefetch
5428 To boost the performance of pipelined requests to closer
5429 match that of a non-proxied environment Squid can try to fetch
5430 up to two requests in parallel from a pipeline.
5432 Defaults to off for bandwidth management and access logging
5436 NAME: high_response_time_warning
5439 LOC: Config.warnings.high_rptm
5442 If the one-minute median response time exceeds this value,
5443 Squid prints a WARNING with debug level 0 to get the
5444 administrators attention. The value is in milliseconds.
5447 NAME: high_page_fault_warning
5449 LOC: Config.warnings.high_pf
5452 If the one-minute average page fault rate exceeds this
5453 value, Squid prints a WARNING with debug level 0 to get
5454 the administrators attention. The value is in page faults
5458 NAME: high_memory_warning
5460 LOC: Config.warnings.high_memory
5463 If the memory usage (as determined by mallinfo) exceeds
5464 this amount, Squid prints a WARNING with debug level 0 to get
5465 the administrators attention.
5468 NAME: sleep_after_fork
5469 COMMENT: (microseconds)
5471 LOC: Config.sleep_after_fork
5474 When this is set to a non-zero value, the main Squid process
5475 sleeps the specified number of microseconds after a fork()
5476 system call. This sleep may help the situation where your
5477 system reports fork() failures due to lack of (virtual)
5478 memory. Note, however, if you have a lot of child
5479 processes, these sleep delays will add up and your
5480 Squid will not service requests for some amount of time
5481 until all the child processes have been started.
5482 On Windows value less then 1000 (1 milliseconds) are