# # SQUID Web Proxy Cache http://www.squid-cache.org/ # ---------------------------------------------------------- # # Squid is the result of efforts by numerous individuals from # the Internet community; see the CONTRIBUTORS file for full # details. Many organizations have provided support for Squid's # development; see the SPONSORS file for full details. Squid is # Copyrighted (C) 2000 by the Regents of the University of # California; see the COPYRIGHT file for full details. Squid # incorporates software developed and/or copyrighted by other # sources; see the CREDITS file for full details. # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA. # COMMENT_START WELCOME TO @SQUID@ ---------------------------- This is the documentation for the Squid configuration file. This documentation can also be found online at: http://www.squid-cache.org/Doc/config/ You may wish to look at the Squid home page and wiki for the FAQ and other documentation: http://www.squid-cache.org/ http://wiki.squid-cache.org/SquidFaq http://wiki.squid-cache.org/ConfigExamples This documentation shows what the defaults for various directives happen to be. If you don't need to change the default, you should leave the line out of your squid.conf in most cases. In some cases "none" refers to no default setting at all, while in other cases it refers to the value of the option - the comments for that keyword indicate if this is the case. COMMENT_END COMMENT_START Configuration options can be included using the "include" directive. Include takes a list of files to include. Quoting and wildcards are supported. For example, include /path/to/included/file/squid.acl.config Includes can be nested up to a hard-coded depth of 16 levels. This arbitrary restriction is to prevent recursive include references from causing Squid entering an infinite loop whilst trying to load configuration files. COMMENT_END # Options Removed in 3.1 NAME: dns_testnames TYPE: obsolete DOC_START Remove this line. DNS is no longer tested on startup. DOC_END NAME: extension_methods TYPE: obsolete DOC_START Remove this line. All valid methods for HTTP are accepted by default. DOC_END # 2.7 Options Removed/Replaced in 3.1 NAME: incoming_rate TYPE: obsolete DOC_NONE NAME: server_http11 TYPE: obsolete DOC_START Remove this line. HTTP/1.1 is supported by default. DOC_END NAME: upgrade_http0.9 TYPE: obsolete DOC_START Remove this line. ICY/1.0 streaming protocol is supported by default. DOC_END NAME: zph_local zph_mode zph_option zph_parent zph_sibling TYPE: obsolete DOC_START Alter these entries. Use the qos_flows directive instead. DOC_END # Options Removed in 3.0 NAME: header_access TYPE: obsolete DOC_START Since squid-3.0 replace with request_header_access or reply_header_access depending on whether you wish to match client requests or server replies. DOC_END NAME: httpd_accel_no_pmtu_disc TYPE: obsolete DOC_START Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead. DOC_END COMMENT_START OPTIONS FOR AUTHENTICATION ----------------------------------------------------------------------------- COMMENT_END NAME: auth_param TYPE: authparam LOC: Config.authConfiguration DEFAULT: none DOC_START This is used to define parameters for the various authentication schemes supported by Squid. format: auth_param scheme parameter [setting] The order in which authentication schemes are presented to the client is dependent on the order the scheme first appears in config file. IE has a bug (it's not RFC 2617 compliant) in that it will use the basic scheme if basic is the first entry presented, even if more secure schemes are presented. For now use the order in the recommended settings section below. If other browsers have difficulties (don't recognize the schemes offered even if you are using basic) either put basic first, or disable the other schemes (by commenting out their program entry). Once an authentication scheme is fully configured, it can only be shutdown by shutting squid down and restarting. Changes can be made on the fly and activated with a reconfigure. I.E. You can change to a different helper, but not unconfigure the helper completely. Please note that while this directive defines how Squid processes authentication it does not automatically activate authentication. To use authentication you must in addition make use of ACLs based on login name in http_access (proxy_auth, proxy_auth_regex or external with %LOGIN used in the format tag). The browser will be challenged for authentication on the first such acl encountered in http_access processing and will also be re-challenged for new login credentials if the request is being denied by a proxy_auth type acl. WARNING: authentication can't be used in a transparently intercepting proxy as the client then thinks it is talking to an origin server and not the proxy. This is a limitation of bending the TCP/IP protocol to transparently intercepting port 80, not a limitation in Squid. Ports flagged 'transparent', 'intercept', or 'tproxy' have authentication disabled. === Parameters for the basic scheme follow. === "program" cmdline Specify the command for the external authenticator. Such a program reads a line containing "username password" and replies "OK" or "ERR" in an endless loop. "ERR" responses may optionally be followed by a error description available as %m in the returned error page. If you use an authenticator, make sure you have 1 acl of type proxy_auth. By default, the basic authentication scheme is not used unless a program is specified. If you want to use the traditional NCSA proxy authentication, set this line to something like auth_param basic program @DEFAULT_PREFIX@/libexec/ncsa_auth @DEFAULT_PREFIX@/etc/passwd "utf8" on|off HTTP uses iso-latin-1 as characterset, while some authentication backends such as LDAP expects UTF-8. If this is set to on Squid will translate the HTTP iso-latin-1 charset to UTF-8 before sending the username & password to the helper. "children" numberofchildren The number of authenticator processes to spawn. If you start too few Squid will have to wait for them to process a backlog of credential verifications, slowing it down. When password verifications are done via a (slow) network you are likely to need lots of authenticator processes. auth_param basic children 5 "concurrency" concurrency The number of concurrent requests the helper can process. The default of 0 is used for helpers who only supports one request at a time. Setting this changes the protocol used to include a channel number first on the request/response line, allowing multiple requests to be sent to the same helper in parallell without wating for the response. Must not be set unless it's known the helper supports this. auth_param basic concurrency 0 "realm" realmstring Specifies the realm name which is to be reported to the client for the basic proxy authentication scheme (part of the text the user will see when prompted their username and password). There is no default. auth_param basic realm Squid proxy-caching web server "credentialsttl" timetolive Specifies how long squid assumes an externally validated username:password pair is valid for - in other words how often the helper program is called for that user. Set this low to force revalidation with short lived passwords. Note setting this high does not impact your susceptibility to replay attacks unless you are using an one-time password system (such as SecureID). If you are using such a system, you will be vulnerable to replay attacks unless you also use the max_user_ip ACL in an http_access rule. "casesensitive" on|off Specifies if usernames are case sensitive. Most user databases are case insensitive allowing the same username to be spelled using both lower and upper case letters, but some are case sensitive. This makes a big difference for user_max_ip ACL processing and similar. auth_param basic casesensitive off === Parameters for the digest scheme follow === "program" cmdline Specify the command for the external authenticator. Such a program reads a line containing "username":"realm" and replies with the appropriate H(A1) value hex encoded or ERR if the user (or his H(A1) hash) does not exists. See rfc 2616 for the definition of H(A1). "ERR" responses may optionally be followed by a error description available as %m in the returned error page. By default, the digest authentication scheme is not used unless a program is specified. If you want to use a digest authenticator, set this line to something like auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass "utf8" on|off HTTP uses iso-latin-1 as characterset, while some authentication backends such as LDAP expects UTF-8. If this is set to on Squid will translate the HTTP iso-latin-1 charset to UTF-8 before sending the username & password to the helper. "children" numberofchildren The number of authenticator processes to spawn (no default). If you start too few Squid will have to wait for them to process a backlog of H(A1) calculations, slowing it down. When the H(A1) calculations are done via a (slow) network you are likely to need lots of authenticator processes. auth_param digest children 5 "realm" realmstring Specifies the realm name which is to be reported to the client for the digest proxy authentication scheme (part of the text the user will see when prompted their username and password). There is no default. auth_param digest realm Squid proxy-caching web server "nonce_garbage_interval" timeinterval Specifies the interval that nonces that have been issued to client_agent's are checked for validity. "nonce_max_duration" timeinterval Specifies the maximum length of time a given nonce will be valid for. "nonce_max_count" number Specifies the maximum number of times a given nonce can be used. "nonce_strictness" on|off Determines if squid requires strict increment-by-1 behavior for nonce counts, or just incrementing (off - for use when useragents generate nonce counts that occasionally miss 1 (ie, 1,2,4,6)). Default off. "check_nonce_count" on|off This directive if set to off can disable the nonce count check completely to work around buggy digest qop implementations in certain mainstream browser versions. Default on to check the nonce count to protect from authentication replay attacks. "post_workaround" on|off This is a workaround to certain buggy browsers who sends an incorrect request digest in POST requests when reusing the same nonce as acquired earlier on a GET request. === NTLM scheme options follow === "program" cmdline Specify the command for the external NTLM authenticator. Such a program reads exchanged NTLMSSP packets with the browser via Squid until authentication is completed. If you use an NTLM authenticator, make sure you have 1 acl of type proxy_auth. By default, the NTLM authenticator_program is not used. auth_param ntlm program @DEFAULT_PREFIX@/bin/ntlm_auth "children" numberofchildren The number of authenticator processes to spawn (no default). If you start too few Squid will have to wait for them to process a backlog of credential verifications, slowing it down. When credential verifications are done via a (slow) network you are likely to need lots of authenticator processes. auth_param ntlm children 5 "keep_alive" on|off Whether to keep the connection open after the initial response where Squid tells the browser which schemes are supported by the proxy. Some browsers are known to present many login popups or to corrupt POST/PUT requests transfer if the connection is not closed. The default is currently OFF to avoid this, but may change. auth_param ntlm keep_alive on === Options for configuring the NEGOTIATE auth-scheme follow === "program" cmdline Specify the command for the external Negotiate authenticator. This protocol is used in Microsoft Active-Directory enabled setups with the Microsoft Internet Explorer or Mozilla Firefox browsers. Its main purpose is to exchange credentials with the Squid proxy using the Kerberos mechanisms. If you use a Negotiate authenticator, make sure you have at least one acl of type proxy_auth active. By default, the negotiate authenticator_program is not used. The only supported program for this role is the ntlm_auth program distributed as part of Samba, version 4 or later. auth_param negotiate program @DEFAULT_PREFIX@/bin/ntlm_auth --helper-protocol=gss-spnego "children" numberofchildren The number of authenticator processes to spawn (no default). If you start too few Squid will have to wait for them to process a backlog of credential verifications, slowing it down. When crendential verifications are done via a (slow) network you are likely to need lots of authenticator processes. auth_param negotiate children 5 "keep_alive" on|off Whether to keep the connection open after the initial response where Squid tells the browser which schemes are supported by the proxy. Some browsers are known to present many login popups or to corrupt POST/PUT requests transfer if the connection is not closed. The default is currently OFF to avoid this, but may change. auth_param negotiate keep_alive on Examples: #Recommended minimum configuration per scheme: #auth_param negotiate program #auth_param negotiate children 5 #auth_param negotiate keep_alive on # #auth_param ntlm program #auth_param ntlm children 5 #auth_param ntlm keep_alive on # #auth_param digest program #auth_param digest children 5 #auth_param digest realm Squid proxy-caching web server #auth_param digest nonce_garbage_interval 5 minutes #auth_param digest nonce_max_duration 30 minutes #auth_param digest nonce_max_count 50 # #auth_param basic program #auth_param basic children 5 #auth_param basic realm Squid proxy-caching web server #auth_param basic credentialsttl 2 hours DOC_END NAME: authenticate_cache_garbage_interval TYPE: time_t DEFAULT: 1 hour LOC: Config.authenticateGCInterval DOC_START The time period between garbage collection across the username cache. This is a tradeoff between memory utilization (long intervals - say 2 days) and CPU (short intervals - say 1 minute). Only change if you have good reason to. DOC_END NAME: authenticate_ttl TYPE: time_t DEFAULT: 1 hour LOC: Config.authenticateTTL DOC_START The time a user & their credentials stay in the logged in user cache since their last request. When the garbage interval passes, all user credentials that have passed their TTL are removed from memory. DOC_END NAME: authenticate_ip_ttl TYPE: time_t LOC: Config.authenticateIpTTL DEFAULT: 0 seconds DOC_START If you use proxy authentication and the 'max_user_ip' ACL, this directive controls how long Squid remembers the IP addresses associated with each user. Use a small value (e.g., 60 seconds) if your users might change addresses quickly, as is the case with dialups. You might be safe using a larger value (e.g., 2 hours) in a corporate LAN environment with relatively static address assignments. DOC_END COMMENT_START ACCESS CONTROLS ----------------------------------------------------------------------------- COMMENT_END NAME: external_acl_type TYPE: externalAclHelper LOC: Config.externalAclHelperList DEFAULT: none DOC_START This option defines external acl classes using a helper program to look up the status external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..] Options: ttl=n TTL in seconds for cached results (defaults to 3600 for 1 hour) negative_ttl=n TTL for cached negative lookups (default same as ttl) children=n Number of acl helper processes spawn to service external acl lookups of this type. (default 5) concurrency=n concurrency level per process. Only used with helpers capable of processing more than one query at a time. cache=n result cache size, 0 is unbounded (default) grace=n Percentage remaining of TTL where a refresh of a cached entry should be initiated without needing to wait for a new reply. (default 0 for no grace period) protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers ipv4 / ipv6 IP protocol used to communicate with this helper. The default is to auto-detect IPv6 and use it when available. FORMAT specifications %LOGIN Authenticated user login name %EXT_USER Username from external acl %IDENT Ident user name %SRC Client IP %SRCPORT Client source port %URI Requested URI %DST Requested host %PROTO Requested protocol %PORT Requested port %PATH Requested URL path %METHOD Request method %MYADDR Squid interface address %MYPORT Squid http_port number %PATH Requested URL-path (including query-string if any) %USER_CERT SSL User certificate in PEM format %USER_CERTCHAIN SSL User certificate chain in PEM format %USER_CERT_xx SSL User certificate subject attribute xx %USER_CA_xx SSL User certificate issuer attribute xx %>{Header} HTTP request header "Header" %>{Hdr:member} HTTP request header "Hdr" list member "member" %>{Hdr:;member} HTTP request header list member using ; as list separator. ; can be any non-alphanumeric character. %<{Header} HTTP reply header "Header" %<{Hdr:member} HTTP reply header "Hdr" list member "member" %<{Hdr:;member} HTTP reply header list member using ; as list separator. ; can be any non-alphanumeric character. %% The percent sign. Useful for helpers which need an unchanging input format. In addition to the above, any string specified in the referencing acl will also be included in the helper request line, after the specified formats (see the "acl external" directive) The helper receives lines per the above format specification, and returns lines starting with OK or ERR indicating the validity of the request and optionally followed by additional keywords with more details. General result syntax: OK/ERR keyword=value ... Defined keywords: user= The users name (login) password= The users password (for login= cache_peer option) message= Message describing the reason. Available as %o in error pages tag= Apply a tag to a request (for both ERR and OK results) Only sets a tag, does not alter existing tags. log= String to be logged in access.log. Available as %ea in logformat specifications If protocol=3.0 (the default) then URL escaping is used to protect each value in both requests and responses. If using protocol=2.5 then all values need to be enclosed in quotes if they may contain whitespace, or the whitespace escaped using \. And quotes or \ characters within the keyword value must be \ escaped. When using the concurrency= option the protocol is changed by introducing a query channel tag infront of the request/response. The query channel tag is a number between 0 and concurrency-1. DOC_END NAME: acl TYPE: acl LOC: Config.aclList DEFAULT: all src all DOC_START Defining an Access List Every access list definition must begin with an aclname and acltype, followed by either type-specific arguments or a quoted filename that they are read from. acl aclname acltype argument ... acl aclname acltype "file" ... When using "file", the file should contain one item per line. By default, regular expressions are CASE-SENSITIVE. To make them case-insensitive, use the -i option. To return case-sensitive use the +i option between patterns, or make a new ACL line without -i. Some acl types require suspending the current request in order to access some external data source. Those which do are marked with the tag [slow], those which don't are marked as [fast]. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for further information ***** ACL TYPES AVAILABLE ***** acl aclname src ip-address/netmask ... # clients IP address [fast] acl aclname src addr1-addr2/netmask ... # range of addresses [fast] acl aclname dst ip-address/netmask ... # URL host's IP address [slow] acl aclname myip ip-address/netmask ... # local socket IP address [fast] acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation) # The arp ACL requires the special configure option --enable-arp-acl. # Furthermore, the ARP ACL code is not portable to all operating systems. # It works on Linux, Solaris, Windows, FreeBSD, and some # other *BSD variants. # [fast] # # NOTE: Squid can only determine the MAC address for clients that are on # the same subnet. If the client is on a different subnet, # then Squid cannot find out its MAC address. acl aclname srcdomain .foo.com ... # reverse lookup, from client IP [slow] acl aclname dstdomain .foo.com ... # Destination server from URL [fast] acl aclname srcdom_regex [-i] \.foo\.com ... # regex matching client name [slow] acl aclname dstdom_regex [-i] \.foo\.com ... # regex matching server [fast] # # For dstdomain and dstdom_regex a reverse lookup is tried if a IP # based URL is used and no match is found. The name "none" is used # if the reverse lookup fails. acl aclname src_as number ... acl aclname dst_as number ... # [fast] # Except for access control, AS numbers can be used for # routing of requests to specific caches. Here's an # example for routing all requests for AS#1241 and only # those to mycache.mydomain.net: # acl asexample dst_as 1241 # cache_peer_access mycache.mydomain.net allow asexample # cache_peer_access mycache_mydomain.net deny all acl aclname peername myPeer ... # [fast] # match against a named cache_peer entry # set unique name= on cache_peer lines for reliable use. acl aclname time [day-abbrevs] [h1:m1-h2:m2] # [fast] # day-abbrevs: # S - Sunday # M - Monday # T - Tuesday # W - Wednesday # H - Thursday # F - Friday # A - Saturday # h1:m1 must be less than h2:m2 acl aclname url_regex [-i] ^http:// ... # regex matching on whole URL [fast] acl aclname urlpath_regex [-i] \.gif$ ... # regex matching on URL path [fast] acl aclname port 80 70 21 0-1024... # destination TCP port [fast] # ranges are alloed acl aclname myport 3128 ... # local socket TCP port [fast] acl aclname myportname 3128 ... # http(s)_port name [fast] acl aclname proto HTTP FTP ... # request protocol [fast] acl aclname method GET POST ... # HTTP request method [fast] acl aclname http_status 200 301 500- 400-403 ... # status code in reply [fast] acl aclname browser [-i] regexp ... # pattern match on User-Agent header (see also req_header below) [fast] acl aclname referer_regex [-i] regexp ... # pattern match on Referer header [fast] # Referer is highly unreliable, so use with care acl aclname ident username ... acl aclname ident_regex [-i] pattern ... # string match on ident output [slow] # use REQUIRED to accept any non-null ident. acl aclname proxy_auth [-i] username ... acl aclname proxy_auth_regex [-i] pattern ... # perform http authentication challenge to the client and match against # supplied credentials [slow] # # takes a list of allowed usernames. # use REQUIRED to accept any valid username. # # Will use proxy authentication in forward-proxy scenarios, and plain # http authenticaiton in reverse-proxy scenarios # # NOTE: when a Proxy-Authentication header is sent but it is not # needed during ACL checking the username is NOT logged # in access.log. # # NOTE: proxy_auth requires a EXTERNAL authentication program # to check username/password combinations (see # auth_param directive). # # NOTE: proxy_auth can't be used in a transparent/intercepting proxy # as the browser needs to be configured for using a proxy in order # to respond to proxy authentication. acl aclname snmp_community string ... # A community string to limit access to your SNMP Agent [fast] # Example: # # acl snmppublic snmp_community public acl aclname maxconn number # This will be matched when the client's IP address has # more than TCP connections established. [fast] # NOTE: This only measures direct TCP links so X-Forwarded-For # indirect clients are not counted. acl aclname max_user_ip [-s] number # This will be matched when the user attempts to log in from more # than different ip addresses. The authenticate_ip_ttl # parameter controls the timeout on the ip entries. [fast] # If -s is specified the limit is strict, denying browsing # from any further IP addresses until the ttl has expired. Without # -s Squid will just annoy the user by "randomly" denying requests. # (the counter is reset each time the limit is reached and a # request is denied) # NOTE: in acceleration mode or where there is mesh of child proxies, # clients may appear to come from multiple addresses if they are # going through proxy farms, so a limit of 1 may cause user problems. acl aclname req_mime_type [-i] mime-type ... # regex match against the mime type of the request generated # by the client. Can be used to detect file upload or some # types HTTP tunneling requests [fast] # NOTE: This does NOT match the reply. You cannot use this # to match the returned file type. acl aclname req_header header-name [-i] any\.regex\.here # regex match against any of the known request headers. May be # thought of as a superset of "browser", "referer" and "mime-type" # ACL [fast] acl aclname rep_mime_type [-i] mime-type ... # regex match against the mime type of the reply received by # squid. Can be used to detect file download or some # types HTTP tunneling requests. [fast] # NOTE: This has no effect in http_access rules. It only has # effect in rules that affect the reply data stream such as # http_reply_access. acl aclname rep_header header-name [-i] any\.regex\.here # regex match against any of the known reply headers. May be # thought of as a superset of "browser", "referer" and "mime-type" # ACLs [fast] acl aclname external class_name [arguments...] # external ACL lookup via a helper class defined by the # external_acl_type directive [slow] acl aclname user_cert attribute values... # match against attributes in a user SSL certificate # attribute is one of DN/C/O/CN/L/ST [fast] acl aclname ca_cert attribute values... # match against attributes a users issuing CA SSL certificate # attribute is one of DN/C/O/CN/L/ST [fast] acl aclname ext_user username ... acl aclname ext_user_regex [-i] pattern ... # string match on username returned by external acl helper [slow] # use REQUIRED to accept any non-null user name. acl aclname tag tagvalue ... # string match on tag returned by external acl helper [slow] Examples: acl macaddress arp 09:00:2b:23:45:67 acl myexample dst_as 1241 acl password proxy_auth REQUIRED acl fileupload req_mime_type -i ^multipart/form-data$ acl javascript rep_mime_type -i ^application/x-javascript$ NOCOMMENT_START # # Recommended minimum configuration: # acl manager proto cache_object acl localhost src 127.0.0.1/32 ::1 acl to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1 # Example rule allowing access from your local networks. # Adapt to list your (internal) IP networks from where browsing # should be allowed acl localnet src 10.0.0.0/8 # RFC1918 possible internal network acl localnet src 172.16.0.0/12 # RFC1918 possible internal network acl localnet src 192.168.0.0/16 # RFC1918 possible internal network acl localnet src fc00::/7 # RFC 4193 local private network range acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines acl SSL_ports port 443 acl Safe_ports port 80 # http acl Safe_ports port 21 # ftp acl Safe_ports port 443 # https acl Safe_ports port 70 # gopher acl Safe_ports port 210 # wais acl Safe_ports port 1025-65535 # unregistered ports acl Safe_ports port 280 # http-mgmt acl Safe_ports port 488 # gss-http acl Safe_ports port 591 # filemaker acl Safe_ports port 777 # multiling http acl CONNECT method CONNECT NOCOMMENT_END DOC_END NAME: follow_x_forwarded_for TYPE: acl_access IFDEF: FOLLOW_X_FORWARDED_FOR LOC: Config.accessList.followXFF DEFAULT_IF_NONE: deny all DOC_START Allowing or Denying the X-Forwarded-For header to be followed to find the original source of a request. Requests may pass through a chain of several other proxies before reaching us. The X-Forwarded-For header will contain a comma-separated list of the IP addresses in the chain, with the rightmost address being the most recent. If a request reaches us from a source that is allowed by this configuration item, then we consult the X-Forwarded-For header to see where that host received the request from. If the X-Forwarded-For header contains multiple addresses, we continue backtracking until we reach an address for which we are not allowed to follow the X-Forwarded-For header, or until we reach the first address in the list. For the purpose of ACL used in the follow_x_forwarded_for directive the src ACL type always matches the address we are testing and srcdomain matches its rDNS. The end result of this process is an IP address that we will refer to as the indirect client address. This address may be treated as the client address for access control, ICAP, delay pools and logging, depending on the acl_uses_indirect_client, icap_uses_indirect_client, delay_pool_uses_indirect_client and log_uses_indirect_client options. This clause only supports fast acl types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details. SECURITY CONSIDERATIONS: Any host for which we follow the X-Forwarded-For header can place incorrect information in the header, and Squid will use the incorrect information as if it were the source address of the request. This may enable remote hosts to bypass any access control restrictions that are based on the client's source addresses. For example: acl localhost src 127.0.0.1 acl my_other_proxy srcdomain .proxy.example.com follow_x_forwarded_for allow localhost follow_x_forwarded_for allow my_other_proxy DOC_END NAME: acl_uses_indirect_client COMMENT: on|off TYPE: onoff IFDEF: FOLLOW_X_FORWARDED_FOR DEFAULT: on LOC: Config.onoff.acl_uses_indirect_client DOC_START Controls whether the indirect client address (see follow_x_forwarded_for) is used instead of the direct client address in acl matching. NOTE: maxconn ACL considers direct TCP links and indirect clients will always have zero. So no match. DOC_END NAME: delay_pool_uses_indirect_client COMMENT: on|off TYPE: onoff IFDEF: FOLLOW_X_FORWARDED_FOR&&DELAY_POOLS DEFAULT: on LOC: Config.onoff.delay_pool_uses_indirect_client DOC_START Controls whether the indirect client address (see follow_x_forwarded_for) is used instead of the direct client address in delay pools. DOC_END NAME: log_uses_indirect_client COMMENT: on|off TYPE: onoff IFDEF: FOLLOW_X_FORWARDED_FOR DEFAULT: on LOC: Config.onoff.log_uses_indirect_client DOC_START Controls whether the indirect client address (see follow_x_forwarded_for) is used instead of the direct client address in the access log. DOC_END NAME: http_access TYPE: acl_access LOC: Config.accessList.http DEFAULT_IF_NONE: deny all DOC_START Allowing or Denying access based on defined access lists Access to the HTTP port: http_access allow|deny [!]aclname ... NOTE on default values: If there are no "access" lines present, the default is to deny the request. If none of the "access" lines cause a match, the default is the opposite of the last line in the list. If the last line was deny, the default is allow. Conversely, if the last line is allow, the default will be deny. For these reasons, it is a good idea to have an "deny all" entry at the end of your access lists to avoid potential confusion. This clause supports both fast and slow acl types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details. NOCOMMENT_START # # Recommended minimum Access Permission configuration: # # Only allow cachemgr access from localhost http_access allow manager localhost http_access deny manager # Deny requests to certain unsafe ports http_access deny !Safe_ports # Deny CONNECT to other than secure SSL ports http_access deny CONNECT !SSL_ports # We strongly recommend the following be uncommented to protect innocent # web applications running on the proxy server who think the only # one who can access services on "localhost" is a local user #http_access deny to_localhost # # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS # # Example rule allowing access from your local networks. # Adapt localnet in the ACL section to list your (internal) IP networks # from where browsing should be allowed http_access allow localnet http_access allow localhost # And finally deny all other access to this proxy http_access deny all NOCOMMENT_END DOC_END NAME: adapted_http_access http_access2 TYPE: acl_access LOC: Config.accessList.adapted_http DEFAULT: none DOC_START Allowing or Denying access based on defined access lists Essentially identical to http_access, but runs after redirectors and ICAP/eCAP adaptation. Allowing access control based on their output. If not set then only http_access is used. DOC_END NAME: http_reply_access TYPE: acl_access LOC: Config.accessList.reply DEFAULT: none DOC_START Allow replies to client requests. This is complementary to http_access. http_reply_access allow|deny [!] aclname ... NOTE: if there are no access lines present, the default is to allow all replies If none of the access lines cause a match the opposite of the last line will apply. Thus it is good practice to end the rules with an "allow all" or "deny all" entry. This clause supports both fast and slow acl types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details. DOC_END NAME: icp_access TYPE: acl_access LOC: Config.accessList.icp DEFAULT_IF_NONE: deny all DOC_START Allowing or Denying access to the ICP port based on defined access lists icp_access allow|deny [!]aclname ... See http_access for details This clause only supports fast acl types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details. # Allow ICP queries from local networks only #icp_access allow localnet #icp_access deny all DOC_END NAME: htcp_access IFDEF: USE_HTCP TYPE: acl_access LOC: Config.accessList.htcp DEFAULT_IF_NONE: deny all DOC_START Allowing or Denying access to the HTCP port based on defined access lists htcp_access allow|deny [!]aclname ... See http_access for details NOTE: The default if no htcp_access lines are present is to deny all traffic. This default may cause problems with peers using the htcp or htcp-oldsquid options. This clause only supports fast acl types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details. # Allow HTCP queries from local networks only #htcp_access allow localnet #htcp_access deny all DOC_END NAME: htcp_clr_access IFDEF: USE_HTCP TYPE: acl_access LOC: Config.accessList.htcp_clr DEFAULT_IF_NONE: deny all DOC_START Allowing or Denying access to purge content using HTCP based on defined access lists htcp_clr_access allow|deny [!]aclname ... See http_access for details This clause only supports fast acl types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details. # Allow HTCP CLR requests from trusted peers acl htcp_clr_peer src 172.16.1.2 htcp_clr_access allow htcp_clr_peer DOC_END NAME: miss_access TYPE: acl_access LOC: Config.accessList.miss DEFAULT_IF_NONE: allow all DOC_START Determins whether network access is permitted when satisfying a request. For example; to force your neighbors to use you as a sibling instead of a parent. acl localclients src 172.16.0.0/16 miss_access allow localclients miss_access deny !localclients This means only your local clients are allowed to fetch relayed/MISS replies from the network and all other clients can only fetch cached objects (HITs). The default for this setting allows all clients who passed the http_access rules to relay via this proxy. This clause only supports fast acl types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details. DOC_END NAME: ident_lookup_access TYPE: acl_access IFDEF: USE_IDENT DEFAULT_IF_NONE: deny all LOC: Ident::TheConfig.identLookup DOC_START A list of ACL elements which, if matched, cause an ident (RFC 931) lookup to be performed for this request. For example, you might choose to always perform ident lookups for your main multi-user Unix boxes, but not for your Macs and PCs. By default, ident lookups are not performed for any requests. To enable ident lookups for specific client addresses, you can follow this example: acl ident_aware_hosts src 198.168.1.0/24 ident_lookup_access allow ident_aware_hosts ident_lookup_access deny all Only src type ACL checks are fully supported. A srcdomain ACL might work at times, but it will not always provide the correct result. This clause only supports fast acl types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details. DOC_END NAME: reply_body_max_size COMMENT: size [acl acl...] TYPE: acl_b_size_t DEFAULT: none LOC: Config.ReplyBodySize DOC_START This option specifies the maximum size of a reply body. It can be used to prevent users from downloading very large files, such as MP3's and movies. When the reply headers are received, the reply_body_max_size lines are processed, and the first line where all (if any) listed ACLs are true is used as the maximum body size for this reply. This size is checked twice. First when we get the reply headers, we check the content-length value. If the content length value exists and is larger than the allowed size, the request is denied and the user receives an error message that says "the request or reply is too large." If there is no content-length, and the reply size exceeds this limit, the client's connection is just closed and they will receive a partial reply. WARNING: downstream caches probably can not detect a partial reply if there is no content-length header, so they will cache partial responses and give them out as hits. You should NOT use this option if you have downstream caches. WARNING: A maximum size smaller than the size of squid's error messages will cause an infinite loop and crash squid. Ensure that the smallest non-zero value you use is greater that the maximum header size plus the size of your largest error page. If you set this parameter none (the default), there will be no limit imposed. Configuration Format is: reply_body_max_size SIZE UNITS [acl ...] ie. reply_body_max_size 10 MB DOC_END COMMENT_START NETWORK OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: http_port ascii_port TYPE: http_port_list DEFAULT: none LOC: Config.Sockaddr.http DOC_START Usage: port [options] hostname:port [options] 1.2.3.4:port [options] The socket addresses where Squid will listen for HTTP client requests. You may specify multiple socket addresses. There are three forms: port alone, hostname with port, and IP address with port. If you specify a hostname or IP address, Squid binds the socket to that specific address. This replaces the old 'tcp_incoming_address' option. Most likely, you do not need to bind to a specific address, so you can use the port number alone. If you are running Squid in accelerator mode, you probably want to listen on port 80 also, or instead. The -a command line option may be used to specify additional port(s) where Squid listens for proxy request. Such ports will be plain proxy ports with no options. You may specify multiple socket addresses on multiple lines. Options: intercept Support for IP-Layer interception of outgoing requests without browser settings. NP: disables authentication and IPv6 on the port. tproxy Support Linux TPROXY for spoofing outgoing connections using the client IP address. NP: disables authentication and maybe IPv6 on the port. accel Accelerator mode. Also needs at least one of vhost / vport / defaultsite. allow-direct Allow direct forwarding in accelerator mode. Normally accelerated requests are denied direct forwarding as if never_direct was used. defaultsite=domainname What to use for the Host: header if it is not present in a request. Determines what site (not origin server) accelerators should consider the default. Implies accel. vhost Accelerator mode using Host header for virtual domain support. Also uses the port as specified in Host: header unless overridden by the vport option. Implies accel. vport Virtual host port support. Using the http_port number instead of the port passed on Host: headers. Implies accel. vport=NN Virtual host port support. Using the specified port number instead of the port passed on Host: headers. Implies accel. protocol= Protocol to reconstruct accelerated requests with. Defaults to http. ignore-cc Ignore request Cache-Control headers. Warning: This option violates HTTP specifications if used in non-accelerator setups. connection-auth[=on|off] use connection-auth=off to tell Squid to prevent forwarding Microsoft connection oriented authentication (NTLM, Negotiate and Kerberos) disable-pmtu-discovery= Control Path-MTU discovery usage: off lets OS decide on what to do (default). transparent disable PMTU discovery when transparent support is enabled. always disable always PMTU discovery. In many setups of transparently intercepting proxies Path-MTU discovery can not work on traffic towards the clients. This is the case when the intercepting device does not fully track connections and fails to forward ICMP must fragment messages to the cache server. If you have such setup and experience that certain clients sporadically hang or never complete requests set disable-pmtu-discovery option to 'transparent'. ssl-bump Intercept each CONNECT request matching ssl_bump ACL, establish secure connection with the client and with the server, decrypt HTTP messages as they pass through Squid, and treat them as unencrypted HTTP messages, becoming the man-in-the-middle. When this option is enabled, additional options become available to specify SSL-related properties of the client-side connection: cert, key, version, cipher, options, clientca, cafile, capath, crlfile, dhparams, sslflags, and sslcontext. See the https_port directive for more information on these options. The ssl_bump option is required to fully enable the SslBump feature. name= Specifies a internal name for the port. Defaults to the port specification (port or addr:port) tcpkeepalive[=idle,interval,timeout] Enable TCP keepalive probes of idle connections. In seconds; idle is the initial time before TCP starts probing the connection, interval how often to probe, and timeout the time before giving up. If you run Squid on a dual-homed machine with an internal and an external interface we recommend you to specify the internal address:port in http_port. This way Squid will only be visible on the internal address. NOCOMMENT_START # Squid normally listens to port 3128 http_port @DEFAULT_HTTP_PORT@ NOCOMMENT_END DOC_END NAME: https_port IFDEF: USE_SSL TYPE: https_port_list DEFAULT: none LOC: Config.Sockaddr.https DOC_START Usage: [ip:]port cert=certificate.pem [key=key.pem] [options...] The socket address where Squid will listen for HTTPS client requests. This is really only useful for situations where you are running squid in accelerator mode and you want to do the SSL work at the accelerator level. You may specify multiple socket addresses on multiple lines, each with their own SSL certificate and/or options. Options: accel Accelerator mode. Also needs at least one of defaultsite or vhost. defaultsite= The name of the https site presented on this port. Implies accel. vhost Accelerator mode using Host header for virtual domain support. Requires a wildcard certificate or other certificate valid for more than one domain. Implies accel. protocol= Protocol to reconstruct accelerated requests with. Defaults to https. cert= Path to SSL certificate (PEM format). key= Path to SSL private key file (PEM format) if not specified, the certificate file is assumed to be a combined certificate and key file. version= The version of SSL/TLS supported 1 automatic (default) 2 SSLv2 only 3 SSLv3 only 4 TLSv1 only cipher= Colon separated list of supported ciphers. NOTE: some ciphers such as EDH ciphers depend on additional settings. If those settings are omitted the ciphers may be silently ignored by the OpenSSL library. options= Various SSL engine options. The most important being: NO_SSLv2 Disallow the use of SSLv2 NO_SSLv3 Disallow the use of SSLv3 NO_TLSv1 Disallow the use of TLSv1 SINGLE_DH_USE Always create a new key when using temporary/ephemeral DH key exchanges See OpenSSL SSL_CTX_set_options documentation for a complete list of options. clientca= File containing the list of CAs to use when requesting a client certificate. cafile= File containing additional CA certificates to use when verifying client certificates. If unset clientca will be used. capath= Directory containing additional CA certificates and CRL lists to use when verifying client certificates. crlfile= File of additional CRL lists to use when verifying the client certificate, in addition to CRLs stored in the capath. Implies VERIFY_CRL flag below. dhparams= File containing DH parameters for temporary/ephemeral DH key exchanges. See OpenSSL documentation for details on how to create this file. WARNING: EDH ciphers will be silently disabled if this option is not set. sslflags= Various flags modifying the use of SSL: DELAYED_AUTH Don't request client certificates immediately, but wait until acl processing requires a certificate (not yet implemented). NO_DEFAULT_CA Don't use the default CA lists built in to OpenSSL. NO_SESSION_REUSE Don't allow for session reuse. Each connection will result in a new SSL session. VERIFY_CRL Verify CRL lists when accepting client certificates. VERIFY_CRL_ALL Verify CRL lists for all certificates in the client certificate chain. sslcontext= SSL session ID context identifier. generate-host-certificates[=] Dynamically create SSL server certificates for the destination hosts of bumped CONNECT requests.When enabled, the cert and key options are used to sign generated certificates. Otherwise generated certificate will be selfsigned. If there is CA certificate life time of generated certificate equals lifetime of CA certificate. If generated certificate is selfsigned lifetime is three years. This option is enabled by default when SslBump is used. See the sslBump option above for more information. dynamic_cert_mem_cache_size=SIZE Approximate total RAM size spent on cached generated certificates. If set to zero, caching is disabled. The default value is 4MB. An average XXX-bit certificate consumes about XXX bytes of RAM. vport Accelerator with IP based virtual host support. vport=NN As above, but uses specified port number rather than the https_port number. Implies accel. name= Specifies a internal name for the port. Defaults to the port specification (port or addr:port) DOC_END NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp TYPE: acl_tos DEFAULT: none LOC: Config.accessList.outgoing_tos DOC_START Allows you to select a TOS/Diffserv value to mark outgoing connections with, based on the username or source address making the request. tcp_outgoing_tos ds-field [!]aclname ... Example where normal_service_net uses the TOS value 0x00 and good_service_net uses 0x20 acl normal_service_net src 10.0.0.0/24 acl good_service_net src 10.0.1.0/24 tcp_outgoing_tos 0x00 normal_service_net tcp_outgoing_tos 0x20 good_service_net TOS/DSCP values really only have local significance - so you should know what you're specifying. For more information, see RFC2474, RFC2475, and RFC3260. The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or "default" to use whatever default your host has. Note that in practice often only multiples of 4 is usable as the two rightmost bits have been redefined for use by ECN (RFC 3168 section 23.1). Processing proceeds in the order specified, and stops at first fully matching line. Note: The use of this directive using client dependent ACLs is incompatible with the use of server side persistent connections. To ensure correct results it is best to set server_persisten_connections to off when using this directive in such configurations. DOC_END NAME: clientside_tos TYPE: acl_tos DEFAULT: none LOC: Config.accessList.clientside_tos DOC_START Allows you to select a TOS/Diffserv value to mark client-side connections with, based on the username or source address making the request. DOC_END NAME: qos_flows TYPE: QosConfig IFDEF: USE_ZPH_QOS DEFAULT: none LOC: Config.zph DOC_START Allows you to select a TOS/DSCP value to mark outgoing connections with, based on where the reply was sourced. TOS values really only have local significance - so you should know what you're specifying. For more information, see RFC2474, RFC2475, and RFC3260. The TOS/DSCP byte must be exactly that - octet value 0x00-0xFF. Note that in practice often only values up to 0x3F are usable as the two highest bits have been redefined for use by ECN (RFC3168). This setting is configured by setting the source TOS values: local-hit=0xFF Value to mark local cache hits. sibling-hit=0xFF Value to mark hits from sibling peers. parent-hit=0xFF Value to mark hits from parent peers. NOTE: 'miss' preserve feature is only possible on Linux at this time. For the following to work correctly, you will need to patch your linux kernel with the TOS preserving ZPH patch. The kernel patch can be downloaded from http://zph.bratcheda.org disable-preserve-miss By default, the existing TOS value of the response coming from the remote server will be retained and masked with miss-mark. This option disables that feature. miss-mask=0xFF Allows you to mask certain bits in the TOS received from the remote server, before copying the value to the TOS sent towards clients. Default: 0xFF (TOS from server is not changed). DOC_END NAME: tcp_outgoing_address TYPE: acl_address DEFAULT: none LOC: Config.accessList.outgoing_address DOC_START Allows you to map requests to different outgoing IP addresses based on the username or source address of the user making the request. tcp_outgoing_address ipaddr [[!]aclname] ... Example where requests from 10.0.0.0/24 will be forwarded with source address 10.1.0.1, 10.0.2.0/24 forwarded with source address 10.1.0.2 and the rest will be forwarded with source address 10.1.0.3. acl normal_service_net src 10.0.0.0/24 acl good_service_net src 10.0.2.0/24 tcp_outgoing_address 10.1.0.1 normal_service_net tcp_outgoing_address 10.1.0.2 good_service_net tcp_outgoing_address 10.1.0.3 Processing proceeds in the order specified, and stops at first fully matching line. Note: The use of this directive using client dependent ACLs is incompatible with the use of server side persistent connections. To ensure correct results it is best to set server_persistent_connections to off when using this directive in such configurations. IPv6 Magic: Squid is built with a capability of bridging the IPv4 and IPv6 internets. tcp_outgoing_address as exampled above breaks this bridging by forcing all outbound traffic through a certain IPv4 which may be on the wrong side of the IPv4/IPv6 boundary. To operate with tcp_outgoing_address and keep the bridging benefits an additional ACL needs to be used which ensures the IPv6-bound traffic is never forced or permitted out the IPv4 interface. # IPv6 destination test along with a dummy access control to perofrm the required DNS # This MUST be place before any ALLOW rules. acl to_ipv6 dst ipv6 http_access deny ipv6 !all tcp_outgoing_address 2001:db8::c001 good_service_net to_ipv6 tcp_outgoing_address 10.1.0.2 good_service_net !to_ipv6 tcp_outgoing_address 2001:db8::beef normal_service_net to_ipv6 tcp_outgoing_address 10.1.0.1 normal_service_net !to_ipv6 tcp_outgoing_address 2001:db8::1 to_ipv6 tcp_outgoing_address 10.1.0.3 !to_ipv6 WARNING: 'dst ipv6' bases its selection assuming DIRECT access. If peers are used the peername ACL are needed to select outgoing address which can link to the peer. 'dst ipv6' is a slow ACL. It will only work here if 'dst' is used previously in the http_access rules to locate the destination IP. Some more magic may be needed for that: http_access allow to_ipv6 !all (meaning, allow if to IPv6 but not from anywhere ;) DOC_END COMMENT_START SSL OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: ssl_unclean_shutdown IFDEF: USE_SSL TYPE: onoff DEFAULT: off LOC: Config.SSL.unclean_shutdown DOC_START Some browsers (especially MSIE) bugs out on SSL shutdown messages. DOC_END NAME: ssl_engine IFDEF: USE_SSL TYPE: string LOC: Config.SSL.ssl_engine DEFAULT: none DOC_START The OpenSSL engine to use. You will need to set this if you would like to use hardware SSL acceleration for example. DOC_END NAME: sslproxy_client_certificate IFDEF: USE_SSL DEFAULT: none LOC: Config.ssl_client.cert TYPE: string DOC_START Client SSL Certificate to use when proxying https:// URLs DOC_END NAME: sslproxy_client_key IFDEF: USE_SSL DEFAULT: none LOC: Config.ssl_client.key TYPE: string DOC_START Client SSL Key to use when proxying https:// URLs DOC_END NAME: sslproxy_version IFDEF: USE_SSL DEFAULT: 1 LOC: Config.ssl_client.version TYPE: int DOC_START SSL version level to use when proxying https:// URLs DOC_END NAME: sslproxy_options IFDEF: USE_SSL DEFAULT: none LOC: Config.ssl_client.options TYPE: string DOC_START SSL engine options to use when proxying https:// URLs The most important being: NO_SSLv2 Disallow the use of SSLv2 NO_SSLv3 Disallow the use of SSLv3 NO_TLSv1 Disallow the use of TLSv1 SINGLE_DH_USE Always create a new key when using temporary/ephemeral DH key exchanges These options vary depending on your SSL engine. See the OpenSSL SSL_CTX_set_options documentation for a complete list of possible options. DOC_END NAME: sslproxy_cipher IFDEF: USE_SSL DEFAULT: none LOC: Config.ssl_client.cipher TYPE: string DOC_START SSL cipher list to use when proxying https:// URLs Colon separated list of supported ciphers. DOC_END NAME: sslproxy_cafile IFDEF: USE_SSL DEFAULT: none LOC: Config.ssl_client.cafile TYPE: string DOC_START file containing CA certificates to use when verifying server certificates while proxying https:// URLs DOC_END NAME: sslproxy_capath IFDEF: USE_SSL DEFAULT: none LOC: Config.ssl_client.capath TYPE: string DOC_START directory containing CA certificates to use when verifying server certificates while proxying https:// URLs DOC_END NAME: ssl_bump IFDEF: USE_SSL TYPE: acl_access LOC: Config.accessList.ssl_bump DEFAULT: none DOC_START This ACL controls which CONNECT requests to an http_port marked with an sslBump flag are actually "bumped". Please see the sslBump flag of an http_port option for more details about decoding proxied SSL connections. By default, no requests are bumped. See also: http_port ssl-bump This clause supports both fast and slow acl types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details. # Example: Bump all requests except those originating from localhost and # those going to webax.com or example.com sites. acl localhost src 127.0.0.1/32 acl broken_sites dstdomain .webax.com acl broken_sites dstdomain .example.com ssl_bump deny localhost ssl_bump deny broken_sites ssl_bump allow all DOC_END NAME: sslproxy_flags IFDEF: USE_SSL DEFAULT: none LOC: Config.ssl_client.flags TYPE: string DOC_START Various flags modifying the use of SSL while proxying https:// URLs: DONT_VERIFY_PEER Accept certificates that fail verification. For refined control, see sslproxy_cert_error. NO_DEFAULT_CA Don't use the default CA list built in to OpenSSL. DOC_END NAME: sslproxy_cert_error IFDEF: USE_SSL DEFAULT: none LOC: Config.ssl_client.cert_error TYPE: acl_access DOC_START Use this ACL to bypass server certificate validation errors. For example, the following lines will bypass all validation errors when talking to servers for example.com. All other validation errors will result in ERR_SECURE_CONNECT_FAIL error. acl BrokenButTrustedServers dstdomain example.com sslproxy_cert_error allow BrokenButTrustedServers sslproxy_cert_error deny all This clause only supports fast acl types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details. Using slow acl types may result in server crashes Without this option, all server certificate validation errors terminate the transaction. Bypassing validation errors is dangerous because an error usually implies that the server cannot be trusted and the connection may be insecure. See also: sslproxy_flags and DONT_VERIFY_PEER. Default setting: sslproxy_cert_error deny all DOC_END NAME: sslpassword_program IFDEF: USE_SSL DEFAULT: none LOC: Config.Program.ssl_password TYPE: string DOC_START Specify a program used for entering SSL key passphrases when using encrypted SSL certificate keys. If not specified keys must either be unencrypted, or Squid started with the -N option to allow it to query interactively for the passphrase. The key file name is given as argument to the program allowing selection of the right password if you have multiple encrypted keys. DOC_END COMMENT_START OPTIONS RELATING TO EXTERNAL SSL_CRTD ----------------------------------------------------------------------------- COMMENT_END NAME: sslcrtd_program TYPE: eol IFDEF: USE_SSL_CRTD DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB LOC: Ssl::TheConfig.ssl_crtd DOC_START Specify the location and options of the executable for ssl_crtd process. @DEFAULT_SSL_CRTD@ program requires -s and -M parameters For more information use: @DEFAULT_SSL_CRTD@ -h DOC_END NAME: sslcrtd_children TYPE: int IFDEF: USE_SSL_CRTD DEFAULT: 5 LOC: Ssl::TheConfig.ssl_crtd_n_running DOC_START The maximum number of processes spawn to service ssl server. The maximum this may be safely set to is 32. You must have at least one ssl_crtd process. DOC_END COMMENT_START OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM ----------------------------------------------------------------------------- COMMENT_END NAME: cache_peer TYPE: peer DEFAULT: none LOC: Config.peers DOC_START To specify other caches in a hierarchy, use the format: cache_peer hostname type http-port icp-port [options] For example, # proxy icp # hostname type port port options # -------------------- -------- ----- ----- ----------- cache_peer parent.foo.net parent 3128 3130 default cache_peer sib1.foo.net sibling 3128 3130 proxy-only cache_peer sib2.foo.net sibling 3128 3130 proxy-only cache_peer example.com parent 80 0 default cache_peer cdn.example.com sibling 3128 0 type: either 'parent', 'sibling', or 'multicast'. proxy-port: The port number where the peer accept HTTP requests. For other Squid proxies this is usually 3128 For web servers this is usually 80 icp-port: Used for querying neighbor caches about objects. Set to 0 if the peer does not support ICP or HTCP. See ICP and HTCP options below for additional details. ==== ICP OPTIONS ==== You MUST also set icp_port and icp_access explicitly when using these options. The defaults will prevent peer traffic using ICP. no-query Disable ICP queries to this neighbor. multicast-responder Indicates the named peer is a member of a multicast group. ICP queries will not be sent directly to the peer, but ICP replies will be accepted from it. closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes. background-ping To only send ICP queries to this neighbor infrequently. This is used to keep the neighbor round trip time updated and is usually used in conjunction with weighted-round-robin. ==== HTCP OPTIONS ==== You MUST also set htcp_port and htcp_access explicitly when using these options. The defaults will prevent peer traffic using HTCP. htcp Send HTCP, instead of ICP, queries to the neighbor. You probably also want to set the "icp-port" to 4827 instead of 3130. htcp-oldsquid Send HTCP to old Squid versions. htcp-no-clr Send HTCP to the neighbor but without sending any CLR requests. This cannot be used with htcp-only-clr. htcp-only-clr Send HTCP to the neighbor but ONLY CLR requests. This cannot be used with htcp-no-clr. htcp-no-purge-clr Send HTCP to the neighbor including CLRs but only when they do not result from PURGE requests. htcp-forward-clr Forward any HTCP CLR requests this proxy receives to the peer. ==== PEER SELECTION METHODS ==== The default peer selection method is ICP, with the first responding peer being used as source. These options can be used for better load balancing. default This is a parent cache which can be used as a "last-resort" if a peer cannot be located by any of the peer-selection methods. If specified more than once, only the first is used. round-robin Load-Balance parents which should be used in a round-robin fashion in the absence of any ICP queries. weight=N can be used to add bias. weighted-round-robin Load-Balance parents which should be used in a round-robin fashion with the frequency of each parent being based on the round trip time. Closer parents are used more often. Usually used for background-ping parents. weight=N can be used to add bias. carp Load-Balance parents which should be used as a CARP array. The requests will be distributed among the parents based on the CARP load balancing hash function based on their weight. userhash Load-balance parents based on the client proxy_auth or ident username. sourcehash Load-balance parents based on the client source IP. multicast-siblings To be used only for cache peers of type "multicast". ALL members of this multicast group have "sibling" relationship with it, not "parent". This is to a multicast group when the requested object would be fetched only from a "parent" cache, anyway. It's useful, e.g., when configuring a pool of redundant Squid proxies, being members of the same multicast group. ==== PEER SELECTION OPTIONS ==== weight=N use to affect the selection of a peer during any weighted peer-selection mechanisms. The weight must be an integer; default is 1, larger weights are favored more. This option does not affect parent selection if a peering protocol is not in use. basetime=N Specify a base amount to be subtracted from round trip times of parents. It is subtracted before division by weight in calculating which parent to fectch from. If the rtt is less than the base time the rtt is set to a minimal value. ttl=N Specify a TTL to use when sending multicast ICP queries to this address. Only useful when sending to a multicast group. Because we don't accept ICP replies from random hosts, you must configure other group members as peers with the 'multicast-responder' option. no-delay To prevent access to this neighbor from influencing the delay pools. digest-url=URL Tell Squid to fetch the cache digest (if digests are enabled) for this host from the specified URL rather than the Squid default location. ==== ACCELERATOR / REVERSE-PROXY OPTIONS ==== originserver Causes this parent to be contacted as an origin server. Meant to be used in accelerator setups when the peer is a web server. forceddomain=name Set the Host header of requests forwarded to this peer. Useful in accelerator setups where the server (peer) expects a certain domain name but clients may request others. ie example.com or www.example.com no-digest Disable request of cache digests. no-netdb-exchange Disables requesting ICMP RTT database (NetDB). ==== AUTHENTICATION OPTIONS ==== login=user:password If this is a personal/workgroup proxy and your parent requires proxy authentication. Note: The string can include URL escapes (i.e. %20 for spaces). This also means % must be written as %%. login=PROXYPASS Send login details received from client to this peer. Authentication is not required, nor changed. Note: This will pass any form of authentication but only Basic auth will work through a proxy unless the connection-auth options are also used. login=PASS Send login details received from client to this peer. Authentication is not required by this option. If there are no client-provided authentication headers to pass on, but username and password are available from either proxy login or an external ACL user= and password= result tags they may be sent instead. Note: To combine this with proxy_auth both proxies must share the same user database as HTTP only allows for a single login (one for proxy, one for origin server). Also be warned this will expose your users proxy password to the peer. USE WITH CAUTION login=*:password Send the username to the upstream cache, but with a fixed password. This is meant to be used when the peer is in another administrative domain, but it is still needed to identify each user. The star can optionally be followed by some extra information which is added to the username. This can be used to identify this proxy to the peer, similar to the login=username:password option above. connection-auth=on|off Tell Squid that this peer does or not support Microsoft connection oriented authentication, and any such challenges received from there should be ignored. Default is auto to automatically determine the status of the peer. ==== SSL / HTTPS / TLS OPTIONS ==== ssl Encrypt connections to this peer with SSL/TLS. sslcert=/path/to/ssl/certificate A client SSL certificate to use when connecting to this peer. sslkey=/path/to/ssl/key The private SSL key corresponding to sslcert above. If 'sslkey' is not specified 'sslcert' is assumed to reference a combined file containing both the certificate and the key. sslversion=1|2|3|4 The SSL version to use when connecting to this peer 1 = automatic (default) 2 = SSL v2 only 3 = SSL v3 only 4 = TLS v1 only sslcipher=... The list of valid SSL ciphers to use when connecting to this peer. ssloptions=... Specify various SSL engine options: NO_SSLv2 Disallow the use of SSLv2 NO_SSLv3 Disallow the use of SSLv3 NO_TLSv1 Disallow the use of TLSv1 See src/ssl_support.c or the OpenSSL documentation for a more complete list. sslcafile=... A file containing additional CA certificates to use when verifying the peer certificate. sslcapath=... A directory containing additional CA certificates to use when verifying the peer certificate. sslcrlfile=... A certificate revocation list file to use when verifying the peer certificate. sslflags=... Specify various flags modifying the SSL implementation: DONT_VERIFY_PEER Accept certificates even if they fail to verify. NO_DEFAULT_CA Don't use the default CA list built in to OpenSSL. DONT_VERIFY_DOMAIN Don't verify the peer certificate matches the server name ssldomain= The peer name as advertised in it's certificate. Used for verifying the correctness of the received peer certificate. If not specified the peer hostname will be used. front-end-https Enable the "Front-End-Https: On" header needed when using Squid as a SSL frontend in front of Microsoft OWA. See MS KB document Q307347 for details on this header. If set to auto the header will only be added if the request is forwarded as a https:// URL. ==== GENERAL OPTIONS ==== connect-timeout=N A peer-specific connect timeout. Also see the peer_connect_timeout directive. connect-fail-limit=N How many times connecting to a peer must fail before it is marked as down. Default is 10. allow-miss Disable Squid's use of only-if-cached when forwarding requests to siblings. This is primarily useful when icp_hit_stale is used by the sibling. To extensive use of this option may result in forwarding loops, and you should avoid having two-way peerings with this option. For example to deny peer usage on requests from peer by denying cache_peer_access if the source is a peer. max-conn=N Limit the amount of connections Squid may open to this peer. see also name=xxx Unique name for the peer. Required if you have multiple peers on the same host but different ports. This name can be used in cache_peer_access and similar directives to dentify the peer. Can be used by outgoing access controls through the peername ACL type. no-tproxy Do not use the client-spoof TPROXY support when forwarding requests to this peer. Use normal address selection instead. proxy-only objects fetched from the peer will not be stored locally. DOC_END NAME: cache_peer_domain cache_host_domain TYPE: hostdomain DEFAULT: none LOC: none DOC_START Use to limit the domains for which a neighbor cache will be queried. Usage: cache_peer_domain cache-host domain [domain ...] cache_peer_domain cache-host !domain For example, specifying cache_peer_domain parent.foo.net .edu has the effect such that UDP query packets are sent to 'bigserver' only when the requested object exists on a server in the .edu domain. Prefixing the domainname with '!' means the cache will be queried for objects NOT in that domain. NOTE: * Any number of domains may be given for a cache-host, either on the same or separate lines. * When multiple domains are given for a particular cache-host, the first matched domain is applied. * Cache hosts with no domain restrictions are queried for all requests. * There are no defaults. * There is also a 'cache_peer_access' tag in the ACL section. DOC_END NAME: cache_peer_access TYPE: peer_access DEFAULT: none LOC: none DOC_START Similar to 'cache_peer_domain' but provides more flexibility by using ACL elements. cache_peer_access cache-host allow|deny [!]aclname ... The syntax is identical to 'http_access' and the other lists of ACL elements. See the comments for 'http_access' below, or the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl). DOC_END NAME: neighbor_type_domain TYPE: hostdomaintype DEFAULT: none LOC: none DOC_START usage: neighbor_type_domain neighbor parent|sibling domain domain ... Modifying the neighbor type for specific domains is now possible. You can treat some domains differently than the the default neighbor type specified on the 'cache_peer' line. Normally it should only be necessary to list domains which should be treated differently because the default neighbor type applies for hostnames which do not match domains listed here. EXAMPLE: cache_peer cache.foo.org parent 3128 3130 neighbor_type_domain cache.foo.org sibling .com .net neighbor_type_domain cache.foo.org sibling .au .de DOC_END NAME: dead_peer_timeout COMMENT: (seconds) DEFAULT: 10 seconds TYPE: time_t LOC: Config.Timeout.deadPeer DOC_START This controls how long Squid waits to declare a peer cache as "dead." If there are no ICP replies received in this amount of time, Squid will declare the peer dead and not expect to receive any further ICP replies. However, it continues to send ICP queries, and will mark the peer as alive upon receipt of the first subsequent ICP reply. This timeout also affects when Squid expects to receive ICP replies from peers. If more than 'dead_peer' seconds have passed since the last ICP reply was received, Squid will not expect to receive an ICP reply on the next query. Thus, if your time between requests is greater than this timeout, you will see a lot of requests sent DIRECT to origin servers instead of to your parents. DOC_END NAME: forward_max_tries DEFAULT: 10 TYPE: int LOC: Config.forward_max_tries DOC_START Controls how many different forward paths Squid will try before giving up. See also forward_timeout. DOC_END NAME: hierarchy_stoplist TYPE: wordlist DEFAULT: none LOC: Config.hierarchy_stoplist DOC_START A list of words which, if found in a URL, cause the object to be handled directly by this cache. In other words, use this to not query neighbor caches for certain objects. You may list this option multiple times. Example: hierarchy_stoplist cgi-bin ? Note: never_direct overrides this option. DOC_END COMMENT_START MEMORY CACHE OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: cache_mem COMMENT: (bytes) TYPE: b_size_t DEFAULT: 256 MB LOC: Config.memMaxSize DOC_START NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE. IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS. 'cache_mem' specifies the ideal amount of memory to be used for: * In-Transit objects * Hot Objects * Negative-Cached objects Data for these objects are stored in 4 KB blocks. This parameter specifies the ideal upper limit on the total size of 4 KB blocks allocated. In-Transit objects take the highest priority. In-transit objects have priority over the others. When additional space is needed for incoming data, negative-cached and hot objects will be released. In other words, the negative-cached and hot objects will fill up any unused space not needed for in-transit objects. If circumstances require, this limit will be exceeded. Specifically, if your incoming request rate requires more than 'cache_mem' of memory to hold in-transit objects, Squid will exceed this limit to satisfy the new requests. When the load decreases, blocks will be freed until the high-water mark is reached. Thereafter, blocks will be used to store hot objects. DOC_END NAME: maximum_object_size_in_memory COMMENT: (bytes) TYPE: b_size_t DEFAULT: 512 KB LOC: Config.Store.maxInMemObjSize DOC_START Objects greater than this size will not be attempted to kept in the memory cache. This should be set high enough to keep objects accessed frequently in memory to improve performance whilst low enough to keep larger objects from hoarding cache_mem. DOC_END NAME: memory_replacement_policy TYPE: removalpolicy LOC: Config.memPolicy DEFAULT: lru DOC_START The memory replacement policy parameter determines which objects are purged from memory when memory space is needed. See cache_replacement_policy for details. DOC_END COMMENT_START DISK CACHE OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: cache_replacement_policy TYPE: removalpolicy LOC: Config.replPolicy DEFAULT: lru DOC_START The cache replacement policy parameter determines which objects are evicted (replaced) when disk space is needed. lru : Squid's original list based LRU policy heap GDSF : Greedy-Dual Size Frequency heap LFUDA: Least Frequently Used with Dynamic Aging heap LRU : LRU policy implemented using a heap Applies to any cache_dir lines listed below this. The LRU policies keeps recently referenced objects. The heap GDSF policy optimizes object hit rate by keeping smaller popular objects in cache so it has a better chance of getting a hit. It achieves a lower byte hit rate than LFUDA though since it evicts larger (possibly popular) objects. The heap LFUDA policy keeps popular objects in cache regardless of their size and thus optimizes byte hit rate at the expense of hit rate since one large, popular object will prevent many smaller, slightly less popular objects from being cached. Both policies utilize a dynamic aging mechanism that prevents cache pollution that can otherwise occur with frequency-based replacement policies. NOTE: if using the LFUDA replacement policy you should increase the value of maximum_object_size above its default of 4096 KB to to maximize the potential byte hit rate improvement of LFUDA. For more information about the GDSF and LFUDA cache replacement policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html. DOC_END NAME: cache_dir TYPE: cachedir DEFAULT: none LOC: Config.cacheSwap DOC_START Usage: cache_dir Type Directory-Name Fs-specific-data [options] You can specify multiple cache_dir lines to spread the cache among different disk partitions. Type specifies the kind of storage system to use. Only "ufs" is built by default. To enable any of the other storage systems see the --enable-storeio configure option. 'Directory' is a top-level directory where cache swap files will be stored. If you want to use an entire disk for caching, this can be the mount-point directory. The directory must exist and be writable by the Squid process. Squid will NOT create this directory for you. The ufs store type: "ufs" is the old well-known Squid storage format that has always been there. cache_dir ufs Directory-Name Mbytes L1 L2 [options] 'Mbytes' is the amount of disk space (MB) to use under this directory. The default is 100 MB. Change this to suit your configuration. Do NOT put the size of your disk drive here. Instead, if you want Squid to use the entire disk drive, subtract 20% and use that value. 'L1' is the number of first-level subdirectories which will be created under the 'Directory'. The default is 16. 'L2' is the number of second-level subdirectories which will be created under each first-level directory. The default is 256. The aufs store type: "aufs" uses the same storage format as "ufs", utilizing POSIX-threads to avoid blocking the main Squid process on disk-I/O. This was formerly known in Squid as async-io. cache_dir aufs Directory-Name Mbytes L1 L2 [options] see argument descriptions under ufs above The diskd store type: "diskd" uses the same storage format as "ufs", utilizing a separate process to avoid blocking the main Squid process on disk-I/O. cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n] see argument descriptions under ufs above Q1 specifies the number of unacknowledged I/O requests when Squid stops opening new files. If this many messages are in the queues, Squid won't open new files. Default is 64 Q2 specifies the number of unacknowledged messages when Squid starts blocking. If this many messages are in the queues, Squid blocks until it receives some replies. Default is 72 When Q1 < Q2 (the default), the cache directory is optimized for lower response time at the expense of a decrease in hit ratio. If Q1 > Q2, the cache directory is optimized for higher hit ratio at the expense of an increase in response time. The coss store type: NP: COSS filesystem in Squid-3 has been deemed too unstable for production use and has thus been removed from this release. We hope that it can be made usable again soon. block-size=n defines the "block size" for COSS cache_dir's. Squid uses file numbers as block numbers. Since file numbers are limited to 24 bits, the block size determines the maximum size of the COSS partition. The default is 512 bytes, which leads to a maximum cache_dir size of 512<<24, or 8 GB. Note you should not change the coss block size after Squid has written some objects to the cache_dir. The coss file store has changed from 2.5. Now it uses a file called 'stripe' in the directory names in the config - and this will be created by squid -z. Common options: no-store, no new objects should be stored to this cache_dir max-size=n, refers to the max object size in bytes this cache_dir supports. It is used to select the cache_dir to store the object. Note: To make optimal use of the max-size limits you should order the cache_dir lines with the smallest max-size value first and the ones with no max-size specification last. Note for coss, max-size must be less than COSS_MEMBUF_SZ, which can be changed with the --with-coss-membuf-size=N configure option. NOCOMMENT_START # Uncomment and adjust the following to add a disk cache directory. #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256 NOCOMMENT_END DOC_END NAME: store_dir_select_algorithm TYPE: string LOC: Config.store_dir_select_algorithm DEFAULT: least-load DOC_START Set this to 'round-robin' as an alternative. DOC_END NAME: max_open_disk_fds TYPE: int LOC: Config.max_open_disk_fds DEFAULT: 0 DOC_START To avoid having disk as the I/O bottleneck Squid can optionally bypass the on-disk cache if more than this amount of disk file descriptors are open. A value of 0 indicates no limit. DOC_END NAME: minimum_object_size COMMENT: (bytes) TYPE: b_int64_t DEFAULT: 0 KB LOC: Config.Store.minObjectSize DOC_START Objects smaller than this size will NOT be saved on disk. The value is specified in kilobytes, and the default is 0 KB, which means there is no minimum. DOC_END NAME: maximum_object_size COMMENT: (bytes) TYPE: b_int64_t DEFAULT: 4096 KB LOC: Config.Store.maxObjectSize DOC_START Objects larger than this size will NOT be saved on disk. The value is specified in kilobytes, and the default is 4MB. If you wish to get a high BYTES hit ratio, you should probably increase this (one 32 MB object hit counts for 3200 10KB hits). If you wish to increase speed more than your want to save bandwidth you should leave this low. NOTE: if using the LFUDA replacement policy you should increase this value to maximize the byte hit rate improvement of LFUDA! See replacement_policy below for a discussion of this policy. DOC_END NAME: cache_swap_low COMMENT: (percent, 0-100) TYPE: int DEFAULT: 90 LOC: Config.Swap.lowWaterMark DOC_NONE NAME: cache_swap_high COMMENT: (percent, 0-100) TYPE: int DEFAULT: 95 LOC: Config.Swap.highWaterMark DOC_START The low- and high-water marks for cache object replacement. Replacement begins when the swap (disk) usage is above the low-water mark and attempts to maintain utilization near the low-water mark. As swap utilization gets close to high-water mark object eviction becomes more aggressive. If utilization is close to the low-water mark less replacement is done each time. Defaults are 90% and 95%. If you have a large cache, 5% could be hundreds of MB. If this is the case you may wish to set these numbers closer together. DOC_END COMMENT_START LOGFILE OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: logformat TYPE: logformat LOC: Config.Log.logformats DEFAULT: none DOC_START Usage: logformat Defines an access log format. The is a string with embedded % format codes % format codes all follow the same basic structure where all but the formatcode is optional. Output strings are automatically escaped as required according to their context and the output format modifiers are usually not needed, but can be specified if an explicit output format is desired. % ["|[|'|#] [-] [[0]width] [{argument}] formatcode " output in quoted string format [ output in squid text log format as used by log_mime_hdrs # output in URL quoted format ' output as-is - left aligned width field width. If starting with 0 the output is zero padded {arg} argument such as header name etc Format codes: % a literal % character >a Client source IP address >A Client FQDN >p Client source port h Original request header. Optional header name argument on the format header[:[separator]element] [http::]>ha The HTTP request headers after adaptation and redirection. Optional header name argument as for >h [http::]h [http::]un User name [http::]ul User name from authentication [http::]ui User name from ident [http::]us User name from SSL [http::]ue User name from external acl helper [http::]>Hs HTTP status code sent to the client [http::]st Received request size including HTTP headers. In the case of chunked requests the chunked encoding metadata are not included [http::]>sh Received HTTP request headers size [http::]a %Ss/%03>Hs %a %Ss/%03>Hs %h] [%a %ui %un [%tl] "%rm %ru HTTP/%rv" %>Hs %a %ui %un [%tl] "%rm %ru HTTP/%rv" %>Hs %h" "%{User-Agent}>h" %Ss:%Sh DOC_END NAME: access_log cache_access_log TYPE: access_log LOC: Config.Log.accesslogs DEFAULT_IF_NONE: @DEFAULT_ACCESS_LOG@ squid DOC_START These files log client request activities. Has a line every HTTP or ICP request. The format is: access_log [ [acl acl ...]] access_log none [acl acl ...]] Will log to the specified file using the specified format (which must be defined in a logformat directive) those entries which match ALL the acl's specified (which must be defined in acl clauses). If no acl is specified, all requests will be logged to this file. To disable logging of a request use the filepath "none", in which case a logformat name should not be specified. To log the request via syslog specify a filepath of "syslog": access_log syslog[:facility.priority] [format [acl1 [acl2 ....]]] where facility could be any of: authpriv, daemon, local0 .. local7 or user. And priority could be any of: err, warning, notice, info, debug. Default: access_log @DEFAULT_ACCESS_LOG@ squid DOC_END NAME: icap_log TYPE: access_log IFDEF: ICAP_CLIENT LOC: Config.Log.icaplogs DEFAULT: none DOC_START ICAP log files record ICAP transaction summaries, one line per transaction. The icap_log option format is: icap_log [ [acl acl ...]] icap_log none [acl acl ...]] Please see access_log option documentation for details. The two kinds of logs share the overall configuration approach and many features. ICAP processing of a single HTTP message or transaction may require multiple ICAP transactions. In such cases, multiple ICAP transaction log lines will correspond to a single access log line. ICAP log uses logformat codes that make sense for an ICAP transaction. Header-related codes are applied to the HTTP header embedded in an ICAP server response, with the following caveats: For REQMOD, there is no HTTP response header unless the ICAP server performed request satisfaction. For RESPMOD, the HTTP request header is the header sent to the ICAP server. For OPTIONS, there are no HTTP headers. The following format codes are also available for ICAP logs: icap::st Bytes sent to the ICAP server (TCP payload only; i.e., what Squid writes to the socket). icap::h ICAP request header(s). Similar to >h. icap::a %icap::to/%03icap::Hs %icap::'. Note, from Squid-3.1 this option has no effect on the cache.log, that log can be rotated separately by using debug_options DOC_END NAME: emulate_httpd_log COMMENT: on|off TYPE: onoff DEFAULT: off LOC: Config.onoff.common_log DOC_START The Cache can emulate the log file format which many 'httpd' programs use. To disable/enable this emulation, set emulate_httpd_log to 'off' or 'on'. The default is to use the native log format since it includes useful information Squid-specific log analyzers use. DOC_END NAME: log_ip_on_direct COMMENT: on|off TYPE: onoff DEFAULT: on LOC: Config.onoff.log_ip_on_direct DOC_START Log the destination IP address in the hierarchy log tag when going direct. Earlier Squid versions logged the hostname here. If you prefer the old way set this to off. DOC_END NAME: mime_table TYPE: string DEFAULT: @DEFAULT_MIME_TABLE@ LOC: Config.mimeTablePathname DOC_START Pathname to Squid's MIME table. You shouldn't need to change this, but the default file contains examples and formatting information if you do. DOC_END NAME: log_mime_hdrs COMMENT: on|off TYPE: onoff LOC: Config.onoff.log_mime_hdrs DEFAULT: off DOC_START The Cache can record both the request and the response MIME headers for each HTTP transaction. The headers are encoded safely and will appear as two bracketed fields at the end of the access log (for either the native or httpd-emulated log formats). To enable this logging set log_mime_hdrs to 'on'. DOC_END NAME: useragent_log TYPE: string LOC: Config.Log.useragent DEFAULT: none IFDEF: USE_USERAGENT_LOG DOC_START Squid will write the User-Agent field from HTTP requests to the filename specified here. By default useragent_log is disabled. DOC_END NAME: referer_log referrer_log TYPE: string LOC: Config.Log.referer DEFAULT: none IFDEF: USE_REFERER_LOG DOC_START Squid will write the Referer field from HTTP requests to the filename specified here. By default referer_log is disabled. Note that "referer" is actually a misspelling of "referrer" however the misspelt version has been accepted into the HTTP RFCs and we accept both. DOC_END NAME: pid_filename TYPE: string DEFAULT: @DEFAULT_PID_FILE@ LOC: Config.pidFilename DOC_START A filename to write the process-id to. To disable, enter "none". DOC_END NAME: log_fqdn COMMENT: on|off TYPE: onoff DEFAULT: off LOC: Config.onoff.log_fqdn DOC_START Turn this on if you wish to log fully qualified domain names in the access.log. To do this Squid does a DNS lookup of all IP's connecting to it. This can (in some situations) increase latency, which makes your cache seem slower for interactive browsing. DOC_END NAME: client_netmask TYPE: address LOC: Config.Addrs.client_netmask DEFAULT: no_addr DOC_START A netmask for client addresses in logfiles and cachemgr output. Change this to protect the privacy of your cache clients. A netmask of 255.255.255.0 will log all IP's in that range with the last digit set to '0'. DOC_END NAME: forward_log IFDEF: WIP_FWD_LOG TYPE: string DEFAULT: none LOC: Config.Log.forward DOC_START Logs the server-side requests. This is currently work in progress. DOC_END NAME: strip_query_terms TYPE: onoff LOC: Config.onoff.strip_query_terms DEFAULT: on DOC_START By default, Squid strips query terms from requested URLs before logging. This protects your user's privacy. DOC_END NAME: buffered_logs COMMENT: on|off TYPE: onoff DEFAULT: off LOC: Config.onoff.buffered_logs DOC_START cache.log log file is written with stdio functions, and as such it can be buffered or unbuffered. By default it will be unbuffered. Buffering it can speed up the writing slightly (though you are unlikely to need to worry unless you run with tons of debugging enabled in which case performance will suffer badly anyway..). DOC_END NAME: netdb_filename TYPE: string DEFAULT: @DEFAULT_NETDB_FILE@ LOC: Config.netdbFilename IFDEF: USE_ICMP DOC_START A filename where Squid stores it's netdb state between restarts. To disable, enter "none". DOC_END COMMENT_START OPTIONS FOR TROUBLESHOOTING ----------------------------------------------------------------------------- COMMENT_END NAME: cache_log TYPE: string DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@ LOC: Debug::cache_log DOC_START Cache logging file. This is where general information about your cache's behavior goes. You can increase the amount of data logged to this file and how often its rotated with "debug_options" DOC_END NAME: debug_options TYPE: eol DEFAULT: ALL,1 LOC: Debug::debugOptions DOC_START Logging options are set as section,level where each source file is assigned a unique section. Lower levels result in less output, Full debugging (level 9) can result in a very large log file, so be careful. The magic word "ALL" sets debugging levels for all sections. We recommend normally running with "ALL,1". The rotate=N option can be used to keep more or less of these logs than would otherwise be kept by logfile_rotate. For most uses a single log should be enough to monitor current events affecting Squid. DOC_END NAME: coredump_dir TYPE: string LOC: Config.coredump_dir DEFAULT_IF_NONE: none DOC_START By default Squid leaves core files in the directory from where it was started. If you set 'coredump_dir' to a directory that exists, Squid will chdir() to that directory at startup and coredump files will be left there. NOCOMMENT_START # Leave coredumps in the first cache dir coredump_dir @DEFAULT_SWAP_DIR@ NOCOMMENT_END DOC_END COMMENT_START OPTIONS FOR FTP GATEWAYING ----------------------------------------------------------------------------- COMMENT_END NAME: ftp_user TYPE: string DEFAULT: Squid@ LOC: Config.Ftp.anon_user DOC_START If you want the anonymous login password to be more informative (and enable the use of picky ftp servers), set this to something reasonable for your domain, like wwwuser@somewhere.net The reason why this is domainless by default is the request can be made on the behalf of a user in any domain, depending on how the cache is used. Some ftp server also validate the email address is valid (for example perl.com). DOC_END NAME: ftp_list_width TYPE: size_t DEFAULT: 32 LOC: Config.Ftp.list_width DOC_START Sets the width of ftp listings. This should be set to fit in the width of a standard browser. Setting this too small can cut off long filenames when browsing ftp sites. DOC_END NAME: ftp_passive TYPE: onoff DEFAULT: on LOC: Config.Ftp.passive DOC_START If your firewall does not allow Squid to use passive connections, turn off this option. Use of ftp_epsv_all option requires this to be ON. DOC_END NAME: ftp_epsv_all TYPE: onoff DEFAULT: off LOC: Config.Ftp.epsv_all DOC_START FTP Protocol extensions permit the use of a special "EPSV ALL" command. NATs may be able to put the connection on a "fast path" through the translator, as the EPRT command will never be used and therefore, translation of the data portion of the segments will never be needed. When a client only expects to do two-way FTP transfers this may be useful. If squid finds that it must do a three-way FTP transfer after issuing an EPSV ALL command, the FTP session will fail. If you have any doubts about this option do not use it. Squid will nicely attempt all other connection methods. Requires ftp_passive to be ON (default) for any effect. DOC_END NAME: ftp_epsv TYPE: onoff DEFAULT: on LOC: Config.Ftp.epsv DOC_START FTP Protocol extensions permit the use of a special "EPSV" command. NATs may be able to put the connection on a "fast path" through the translator using EPSV, as the EPRT command will never be used and therefore, translation of the data portion of the segments will never be needed. Turning this OFF will prevent EPSV being attempted. WARNING: Doing so will convert Squid back to the old behavior with all the related problems with external NAT devices/layers. Requires ftp_passive to be ON (default) for any effect. DOC_END NAME: ftp_eprt TYPE: onoff DEFAULT: on LOC: Config.Ftp.eprt DOC_START FTP Protocol extensions permit the use of a special "EPRT" command. This extension provides a protocol neutral alternative to the IPv4-only PORT command. When supported it enables active FTP data channels over IPv6 and efficient NAT handling. Turning this OFF will prevent EPRT being attempted and will skip straight to using PORT for IPv4 servers. Some devices are known to not handle this extension correctly and may result in crashes. Devices which suport EPRT enough to fail cleanly will result in Squid attempting PORT anyway. This directive should only be disabled when EPRT results in device failures. WARNING: Doing so will convert Squid back to the old behavior with all the related problems with external NAT devices/layers and IPv4-only FTP. DOC_END NAME: ftp_sanitycheck TYPE: onoff DEFAULT: on LOC: Config.Ftp.sanitycheck DOC_START For security and data integrity reasons Squid by default performs sanity checks of the addresses of FTP data connections ensure the data connection is to the requested server. If you need to allow FTP connections to servers using another IP address for the data connection turn this off. DOC_END NAME: ftp_telnet_protocol TYPE: onoff DEFAULT: on LOC: Config.Ftp.telnet DOC_START The FTP protocol is officially defined to use the telnet protocol as transport channel for the control connection. However, many implementations are broken and does not respect this aspect of the FTP protocol. If you have trouble accessing files with ASCII code 255 in the path or similar problems involving this ASCII code you can try setting this directive to off. If that helps, report to the operator of the FTP server in question that their FTP server is broken and does not follow the FTP standard. DOC_END COMMENT_START OPTIONS FOR EXTERNAL SUPPORT PROGRAMS ----------------------------------------------------------------------------- COMMENT_END NAME: diskd_program TYPE: string DEFAULT: @DEFAULT_DISKD@ LOC: Config.Program.diskd DOC_START Specify the location of the diskd executable. Note this is only useful if you have compiled in diskd as one of the store io modules. DOC_END NAME: unlinkd_program IFDEF: USE_UNLINKD TYPE: string DEFAULT: @DEFAULT_UNLINKD@ LOC: Config.Program.unlinkd DOC_START Specify the location of the executable for file deletion process. DOC_END NAME: pinger_program TYPE: string DEFAULT: @DEFAULT_PINGER@ LOC: Config.pinger.program IFDEF: USE_ICMP DOC_START Specify the location of the executable for the pinger process. DOC_END NAME: pinger_enable TYPE: onoff DEFAULT: off LOC: Config.pinger.enable IFDEF: USE_ICMP DOC_START Control whether the pinger is active at run-time. Enables turning ICMP pinger on and off with a simple squid -k reconfigure. DOC_END COMMENT_START OPTIONS FOR URL REWRITING ----------------------------------------------------------------------------- COMMENT_END NAME: url_rewrite_program redirect_program TYPE: wordlist LOC: Config.Program.redirect DEFAULT: none DOC_START Specify the location of the executable URL rewriter to use. Since they can perform almost any function there isn't one included. For each requested URL, the rewriter will receive on line with the format URL client_ip "/" fqdn user method [ kvpairs] In the future, the rewriter interface will be extended with key=value pairs ("kvpairs" shown above). Rewriter programs should be prepared to receive and possibly ignore additional whitespace-separated tokens on each input line. And the rewriter may return a rewritten URL. The other components of the request line does not need to be returned (ignored if they are). The rewriter can also indicate that a client-side redirect should be performed to the new URL. This is done by prefixing the returned URL with "301:" (moved permanently) or 302: (moved temporarily), etc. By default, a URL rewriter is not used. DOC_END NAME: url_rewrite_children redirect_children TYPE: int DEFAULT: 5 LOC: Config.redirectChildren DOC_START The number of redirector processes to spawn. If you start too few Squid will have to wait for them to process a backlog of URLs, slowing it down. If you start too many they will use RAM and other system resources. DOC_END NAME: url_rewrite_concurrency redirect_concurrency TYPE: int DEFAULT: 0 LOC: Config.redirectConcurrency DOC_START The number of requests each redirector helper can handle in parallel. Defaults to 0 which indicates the redirector is a old-style single threaded redirector. When this directive is set to a value >= 1 then the protocol used to communicate with the helper is modified to include a request ID in front of the request/response. The request ID from the request must be echoed back with the response to that request. DOC_END NAME: url_rewrite_host_header redirect_rewrites_host_header TYPE: onoff DEFAULT: on LOC: Config.onoff.redir_rewrites_host DOC_START By default Squid rewrites any Host: header in redirected requests. If you are running an accelerator this may not be a wanted effect of a redirector. WARNING: Entries are cached on the result of the URL rewriting process, so be careful if you have domain-virtual hosts. DOC_END NAME: url_rewrite_access redirector_access TYPE: acl_access DEFAULT: none LOC: Config.accessList.redirector DOC_START If defined, this access list specifies which requests are sent to the redirector processes. By default all requests are sent. This clause supports both fast and slow acl types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details. DOC_END NAME: url_rewrite_bypass redirector_bypass TYPE: onoff LOC: Config.onoff.redirector_bypass DEFAULT: off DOC_START When this is 'on', a request will not go through the redirector if all redirectors are busy. If this is 'off' and the redirector queue grows too large, Squid will exit with a FATAL error and ask you to increase the number of redirectors. You should only enable this if the redirectors are not critical to your caching system. If you use redirectors for access control, and you enable this option, users may have access to pages they should not be allowed to request. DOC_END COMMENT_START OPTIONS FOR TUNING THE CACHE ----------------------------------------------------------------------------- COMMENT_END NAME: cache no_cache TYPE: acl_access DEFAULT: none LOC: Config.accessList.noCache DOC_START A list of ACL elements which, if matched and denied, cause the request to not be satisfied from the cache and the reply to not be cached. In other words, use this to force certain objects to never be cached. You must use the words 'allow' or 'deny' to indicate whether items matching the ACL should be allowed or denied into the cache. Default is to allow all to be cached. This clause supports both fast and slow acl types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details. DOC_END NAME: refresh_pattern TYPE: refreshpattern LOC: Config.Refresh DEFAULT: none DOC_START usage: refresh_pattern [-i] regex min percent max [options] By default, regular expressions are CASE-SENSITIVE. To make them case-insensitive, use the -i option. 'Min' is the time (in minutes) an object without an explicit expiry time should be considered fresh. The recommended value is 0, any higher values may cause dynamic applications to be erroneously cached unless the application designer has taken the appropriate actions. 'Percent' is a percentage of the objects age (time since last modification age) an object without explicit expiry time will be considered fresh. 'Max' is an upper limit on how long objects without an explicit expiry time will be considered fresh. options: override-expire override-lastmod reload-into-ims ignore-reload ignore-no-cache ignore-no-store ignore-must-revalidate ignore-private ignore-auth refresh-ims override-expire enforces min age even if the server sent an explicit expiry time (e.g., with the Expires: header or Cache-Control: max-age). Doing this VIOLATES the HTTP standard. Enabling this feature could make you liable for problems which it causes. Note: override-expire does not enforce staleness - it only extends freshness / min. If the server returns a Expires time which is longer than your max time, Squid will still consider the object fresh for that period of time. override-lastmod enforces min age even on objects that were modified recently. reload-into-ims changes client no-cache or ``reload'' to If-Modified-Since requests. Doing this VIOLATES the HTTP standard. Enabling this feature could make you liable for problems which it causes. ignore-reload ignores a client no-cache or ``reload'' header. Doing this VIOLATES the HTTP standard. Enabling this feature could make you liable for problems which it causes. ignore-no-cache ignores any ``Pragma: no-cache'' and ``Cache-control: no-cache'' headers received from a server. The HTTP RFC never allows the use of this (Pragma) header from a server, only a client, though plenty of servers send it anyway. ignore-no-store ignores any ``Cache-control: no-store'' headers received from a server. Doing this VIOLATES the HTTP standard. Enabling this feature could make you liable for problems which it causes. ignore-must-revalidate ignores any ``Cache-Control: must-revalidate`` headers received from a server. Doing this VIOLATES the HTTP standard. Enabling this feature could make you liable for problems which it causes. ignore-private ignores any ``Cache-control: private'' headers received from a server. Doing this VIOLATES the HTTP standard. Enabling this feature could make you liable for problems which it causes. ignore-auth caches responses to requests with authorization, as if the originserver had sent ``Cache-control: public'' in the response header. Doing this VIOLATES the HTTP standard. Enabling this feature could make you liable for problems which it causes. refresh-ims causes squid to contact the origin server when a client issues an If-Modified-Since request. This ensures that the client will receive an updated version if one is available. Basically a cached object is: FRESH if expires < now, else STALE STALE if age > max FRESH if lm-factor < percent, else STALE FRESH if age < min else STALE The refresh_pattern lines are checked in the order listed here. The first entry which matches is used. If none of the entries match the default will be used. Note, you must uncomment all the default lines if you want to change one. The default setting is only active if none is used. NOCOMMENT_START # Add any of your own refresh_pattern entries above these. refresh_pattern ^ftp: 1440 20% 10080 refresh_pattern ^gopher: 1440 0% 1440 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0 refresh_pattern . 0 20% 4320 NOCOMMENT_END DOC_END NAME: quick_abort_min COMMENT: (KB) TYPE: kb_int64_t DEFAULT: 16 KB LOC: Config.quickAbort.min DOC_NONE NAME: quick_abort_max COMMENT: (KB) TYPE: kb_int64_t DEFAULT: 16 KB LOC: Config.quickAbort.max DOC_NONE NAME: quick_abort_pct COMMENT: (percent) TYPE: int DEFAULT: 95 LOC: Config.quickAbort.pct DOC_START The cache by default continues downloading aborted requests which are almost completed (less than 16 KB remaining). This may be undesirable on slow (e.g. SLIP) links and/or very busy caches. Impatient users may tie up file descriptors and bandwidth by repeatedly requesting and immediately aborting downloads. When the user aborts a request, Squid will check the quick_abort values to the amount of data transfered until then. If the transfer has less than 'quick_abort_min' KB remaining, it will finish the retrieval. If the transfer has more than 'quick_abort_max' KB remaining, it will abort the retrieval. If more than 'quick_abort_pct' of the transfer has completed, it will finish the retrieval. If you do not want any retrieval to continue after the client has aborted, set both 'quick_abort_min' and 'quick_abort_max' to '0 KB'. If you want retrievals to always continue if they are being cached set 'quick_abort_min' to '-1 KB'. DOC_END NAME: read_ahead_gap COMMENT: buffer-size TYPE: b_int64_t LOC: Config.readAheadGap DEFAULT: 16 KB DOC_START The amount of data the cache will buffer ahead of what has been sent to the client when retrieving an object from another server. DOC_END NAME: negative_ttl IFDEF: HTTP_VIOLATIONS COMMENT: time-units TYPE: time_t LOC: Config.negativeTtl DEFAULT: 0 seconds DOC_START Set the Default Time-to-Live (TTL) for failed requests. Certain types of failures (such as "connection refused" and "404 Not Found") are able to be negatively-cached for a short time. Modern web servers should provide Expires: header, however if they do not this can provide a minimum TTL. The default is not to cache errors with unknown expiry details. Note that this is different from negative caching of DNS lookups. WARNING: Doing this VIOLATES the HTTP standard. Enabling this feature could make you liable for problems which it causes. DOC_END NAME: positive_dns_ttl COMMENT: time-units TYPE: time_t LOC: Config.positiveDnsTtl DEFAULT: 6 hours DOC_START Upper limit on how long Squid will cache positive DNS responses. Default is 6 hours (360 minutes). This directive must be set larger than negative_dns_ttl. DOC_END NAME: negative_dns_ttl COMMENT: time-units TYPE: time_t LOC: Config.negativeDnsTtl DEFAULT: 1 minutes DOC_START Time-to-Live (TTL) for negative caching of failed DNS lookups. This also sets the lower cache limit on positive lookups. Minimum value is 1 second, and it is not recommendable to go much below 10 seconds. DOC_END NAME: range_offset_limit COMMENT: (bytes) TYPE: b_int64_t LOC: Config.rangeOffsetLimit DEFAULT: 0 KB DOC_START Sets a upper limit on how far into the the file a Range request may be to cause Squid to prefetch the whole file. If beyond this limit Squid forwards the Range request as it is and the result is NOT cached. This is to stop a far ahead range request (lets say start at 17MB) from making Squid fetch the whole object up to that point before sending anything to the client. A value of 0 causes Squid to never fetch more than the client requested. (default) A value of -1 causes Squid to always fetch the object from the beginning so it may cache the result. (2.0 style) NP: Using -1 here will override any quick_abort settings that may otherwise apply to the range request. The range request will be fully fetched from start to finish regardless of the client actions. This affects bandwidth usage. DOC_END NAME: minimum_expiry_time COMMENT: (seconds) TYPE: time_t LOC: Config.minimum_expiry_time DEFAULT: 60 seconds DOC_START The minimum caching time according to (Expires - Date) Headers Squid honors if the object can't be revalidated defaults to 60 seconds. In reverse proxy environments it might be desirable to honor shorter object lifetimes. It is most likely better to make your server return a meaningful Last-Modified header however. In ESI environments where page fragments often have short lifetimes, this will often be best set to 0. DOC_END NAME: store_avg_object_size COMMENT: (kbytes) TYPE: kb_int64_t DEFAULT: 13 KB LOC: Config.Store.avgObjectSize DOC_START Average object size, used to estimate number of objects your cache can hold. The default is 13 KB. DOC_END NAME: store_objects_per_bucket TYPE: int DEFAULT: 20 LOC: Config.Store.objectsPerBucket DOC_START Target number of objects per bucket in the store hash table. Lowering this value increases the total number of buckets and also the storage maintenance rate. The default is 20. DOC_END COMMENT_START HTTP OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: request_header_max_size COMMENT: (KB) TYPE: b_size_t DEFAULT: 64 KB LOC: Config.maxRequestHeaderSize DOC_START This specifies the maximum size for HTTP headers in a request. Request headers are usually relatively small (about 512 bytes). Placing a limit on the request header size will catch certain bugs (for example with persistent connections) and possibly buffer-overflow or denial-of-service attacks. DOC_END NAME: reply_header_max_size COMMENT: (KB) TYPE: b_size_t DEFAULT: 64 KB LOC: Config.maxReplyHeaderSize DOC_START This specifies the maximum size for HTTP headers in a reply. Reply headers are usually relatively small (about 512 bytes). Placing a limit on the reply header size will catch certain bugs (for example with persistent connections) and possibly buffer-overflow or denial-of-service attacks. DOC_END NAME: request_body_max_size COMMENT: (bytes) TYPE: b_int64_t DEFAULT: 0 KB LOC: Config.maxRequestBodySize DOC_START This specifies the maximum size for an HTTP request body. In other words, the maximum size of a PUT/POST request. A user who attempts to send a request with a body larger than this limit receives an "Invalid Request" error message. If you set this parameter to a zero (the default), there will be no limit imposed. DOC_END NAME: client_request_buffer_max_size COMMENT: (bytes) TYPE: b_size_t DEFAULT: 512 KB LOC: Config.maxRequestBufferSize DOC_START This specifies the maximum buffer size of a client request. It prevents squid eating too much memory when somebody uploads a large file. DOC_END NAME: chunked_request_body_max_size COMMENT: (bytes) TYPE: b_int64_t DEFAULT: 64 KB LOC: Config.maxChunkedRequestBodySize DOC_START A broken or confused HTTP/1.1 client may send a chunked HTTP request to Squid. Squid does not have full support for that feature yet. To cope with such requests, Squid buffers the entire request and then dechunks request body to create a plain HTTP/1.0 request with a known content length. The plain request is then used by the rest of Squid code as usual. The option value specifies the maximum size of the buffer used to hold the request before the conversion. If the chunked request size exceeds the specified limit, the conversion fails, and the client receives an "unsupported request" error, as if dechunking was disabled. Dechunking is enabled by default. To disable conversion of chunked requests, set the maximum to zero. Request dechunking feature and this option in particular are a temporary hack. When chunking requests and responses are fully supported, there will be no need to buffer a chunked request. DOC_END NAME: broken_posts IFDEF: HTTP_VIOLATIONS TYPE: acl_access DEFAULT: none LOC: Config.accessList.brokenPosts DOC_START A list of ACL elements which, if matched, causes Squid to send an extra CRLF pair after the body of a PUT/POST request. Some HTTP servers has broken implementations of PUT/POST, and rely on an extra CRLF pair sent by some WWW clients. Quote from RFC2616 section 4.1 on this matter: Note: certain buggy HTTP/1.0 client implementations generate an extra CRLF's after a POST request. To restate what is explicitly forbidden by the BNF, an HTTP/1.1 client must not preface or follow a request with an extra CRLF. This clause only supports fast acl types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details. Example: acl buggy_server url_regex ^http://.... broken_posts allow buggy_server DOC_END NAME: icap_uses_indirect_client COMMENT: on|off TYPE: onoff IFDEF: FOLLOW_X_FORWARDED_FOR&&ICAP_CLIENT DEFAULT: on LOC: Adaptation::Icap::TheConfig.icap_uses_indirect_client DOC_START Controls whether the indirect client IP address (instead of the direct client IP address) is passed to adaptation services. See also: follow_x_forwarded_for adaptation_send_client_ip DOC_END NAME: via IFDEF: HTTP_VIOLATIONS COMMENT: on|off TYPE: onoff DEFAULT: on LOC: Config.onoff.via DOC_START If set (default), Squid will include a Via header in requests and replies as required by RFC2616. DOC_END NAME: ie_refresh COMMENT: on|off TYPE: onoff LOC: Config.onoff.ie_refresh DEFAULT: off DOC_START Microsoft Internet Explorer up until version 5.5 Service Pack 1 has an issue with transparent proxies, wherein it is impossible to force a refresh. Turning this on provides a partial fix to the problem, by causing all IMS-REFRESH requests from older IE versions to check the origin server for fresh content. This reduces hit ratio by some amount (~10% in my experience), but allows users to actually get fresh content when they want it. Note because Squid cannot tell if the user is using 5.5 or 5.5SP1, the behavior of 5.5 is unchanged from old versions of Squid (i.e. a forced refresh is impossible). Newer versions of IE will, hopefully, continue to have the new behavior and will be handled based on that assumption. This option defaults to the old Squid behavior, which is better for hit ratios but worse for clients using IE, if they need to be able to force fresh content. DOC_END NAME: vary_ignore_expire COMMENT: on|off TYPE: onoff LOC: Config.onoff.vary_ignore_expire DEFAULT: off DOC_START Many HTTP servers supporting Vary gives such objects immediate expiry time with no cache-control header when requested by a HTTP/1.0 client. This option enables Squid to ignore such expiry times until HTTP/1.1 is fully implemented. WARNING: If turned on this may eventually cause some varying objects not intended for caching to get cached. DOC_END NAME: request_entities TYPE: onoff LOC: Config.onoff.request_entities DEFAULT: off DOC_START Squid defaults to deny GET and HEAD requests with request entities, as the meaning of such requests are undefined in the HTTP standard even if not explicitly forbidden. Set this directive to on if you have clients which insists on sending request entities in GET or HEAD requests. But be warned that there is server software (both proxies and web servers) which can fail to properly process this kind of request which may make you vulnerable to cache pollution attacks if enabled. DOC_END NAME: request_header_access IFDEF: HTTP_VIOLATIONS TYPE: http_header_access[] LOC: Config.request_header_access DEFAULT: none DOC_START Usage: request_header_access header_name allow|deny [!]aclname ... WARNING: Doing this VIOLATES the HTTP standard. Enabling this feature could make you liable for problems which it causes. This option replaces the old 'anonymize_headers' and the older 'http_anonymizer' option with something that is much more configurable. This new method creates a list of ACLs for each header, allowing you very fine-tuned header mangling. This option only applies to request headers, i.e., from the client to the server. You can only specify known headers for the header name. Other headers are reclassified as 'Other'. You can also refer to all the headers with 'All'. For example, to achieve the same behavior as the old 'http_anonymizer standard' option, you should use: request_header_access From deny all request_header_access Referer deny all request_header_access Server deny all request_header_access User-Agent deny all request_header_access WWW-Authenticate deny all request_header_access Link deny all Or, to reproduce the old 'http_anonymizer paranoid' feature you should use: request_header_access Allow allow all request_header_access Authorization allow all request_header_access WWW-Authenticate allow all request_header_access Proxy-Authorization allow all request_header_access Proxy-Authenticate allow all request_header_access Cache-Control allow all request_header_access Content-Encoding allow all request_header_access Content-Length allow all request_header_access Content-Type allow all request_header_access Date allow all request_header_access Expires allow all request_header_access Host allow all request_header_access If-Modified-Since allow all request_header_access Last-Modified allow all request_header_access Location allow all request_header_access Pragma allow all request_header_access Accept allow all request_header_access Accept-Charset allow all request_header_access Accept-Encoding allow all request_header_access Accept-Language allow all request_header_access Content-Language allow all request_header_access Mime-Version allow all request_header_access Retry-After allow all request_header_access Title allow all request_header_access Connection allow all request_header_access All deny all although many of those are HTTP reply headers, and so should be controlled with the reply_header_access directive. By default, all headers are allowed (no anonymizing is performed). DOC_END NAME: reply_header_access IFDEF: HTTP_VIOLATIONS TYPE: http_header_access[] LOC: Config.reply_header_access DEFAULT: none DOC_START Usage: reply_header_access header_name allow|deny [!]aclname ... WARNING: Doing this VIOLATES the HTTP standard. Enabling this feature could make you liable for problems which it causes. This option only applies to reply headers, i.e., from the server to the client. This is the same as request_header_access, but in the other direction. This option replaces the old 'anonymize_headers' and the older 'http_anonymizer' option with something that is much more configurable. This new method creates a list of ACLs for each header, allowing you very fine-tuned header mangling. You can only specify known headers for the header name. Other headers are reclassified as 'Other'. You can also refer to all the headers with 'All'. For example, to achieve the same behavior as the old 'http_anonymizer standard' option, you should use: reply_header_access From deny all reply_header_access Referer deny all reply_header_access Server deny all reply_header_access User-Agent deny all reply_header_access WWW-Authenticate deny all reply_header_access Link deny all Or, to reproduce the old 'http_anonymizer paranoid' feature you should use: reply_header_access Allow allow all reply_header_access Authorization allow all reply_header_access WWW-Authenticate allow all reply_header_access Proxy-Authorization allow all reply_header_access Proxy-Authenticate allow all reply_header_access Cache-Control allow all reply_header_access Content-Encoding allow all reply_header_access Content-Length allow all reply_header_access Content-Type allow all reply_header_access Date allow all reply_header_access Expires allow all reply_header_access Host allow all reply_header_access If-Modified-Since allow all reply_header_access Last-Modified allow all reply_header_access Location allow all reply_header_access Pragma allow all reply_header_access Accept allow all reply_header_access Accept-Charset allow all reply_header_access Accept-Encoding allow all reply_header_access Accept-Language allow all reply_header_access Content-Language allow all reply_header_access Mime-Version allow all reply_header_access Retry-After allow all reply_header_access Title allow all reply_header_access Connection allow all reply_header_access All deny all although the HTTP request headers won't be usefully controlled by this directive -- see request_header_access for details. By default, all headers are allowed (no anonymizing is performed). DOC_END NAME: request_header_replace header_replace IFDEF: HTTP_VIOLATIONS TYPE: http_header_replace[] LOC: Config.request_header_access DEFAULT: none DOC_START Usage: request_header_replace header_name message Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit) This option allows you to change the contents of headers denied with request_header_access above, by replacing them with some fixed string. This replaces the old fake_user_agent option. This only applies to request headers, not reply headers. By default, headers are removed if denied. DOC_END NAME: reply_header_replace IFDEF: HTTP_VIOLATIONS TYPE: http_header_replace[] LOC: Config.reply_header_access DEFAULT: none DOC_START Usage: reply_header_replace header_name message Example: reply_header_replace Server Foo/1.0 This option allows you to change the contents of headers denied with reply_header_access above, by replacing them with some fixed string. This only applies to reply headers, not request headers. By default, headers are removed if denied. DOC_END NAME: relaxed_header_parser COMMENT: on|off|warn TYPE: tristate LOC: Config.onoff.relaxed_header_parser DEFAULT: on DOC_START In the default "on" setting Squid accepts certain forms of non-compliant HTTP messages where it is unambiguous what the sending application intended even if the message is not correctly formatted. The messages is then normalized to the correct form when forwarded by Squid. If set to "warn" then a warning will be emitted in cache.log each time such HTTP error is encountered. If set to "off" then such HTTP errors will cause the request or response to be rejected. DOC_END NAME: ignore_expect_100 COMMENT: on|off IFDEF: HTTP_VIOLATIONS TYPE: onoff LOC: Config.onoff.ignore_expect_100 DEFAULT: off DOC_START This option makes Squid ignore any Expect: 100-continue header present in the request. RFC 2616 requires that Squid being unable to satisfy the response expectation MUST return a 417 error. Note: Enabling this is a HTTP protocol violation, but some clients may not handle it well.. DOC_END COMMENT_START TIMEOUTS ----------------------------------------------------------------------------- COMMENT_END NAME: forward_timeout COMMENT: time-units TYPE: time_t LOC: Config.Timeout.forward DEFAULT: 4 minutes DOC_START This parameter specifies how long Squid should at most attempt in finding a forwarding path for the request before giving up. DOC_END NAME: connect_timeout COMMENT: time-units TYPE: time_t LOC: Config.Timeout.connect DEFAULT: 1 minute DOC_START This parameter specifies how long to wait for the TCP connect to the requested server or peer to complete before Squid should attempt to find another path where to forward the request. DOC_END NAME: peer_connect_timeout COMMENT: time-units TYPE: time_t LOC: Config.Timeout.peer_connect DEFAULT: 30 seconds DOC_START This parameter specifies how long to wait for a pending TCP connection to a peer cache. The default is 30 seconds. You may also set different timeout values for individual neighbors with the 'connect-timeout' option on a 'cache_peer' line. DOC_END NAME: read_timeout COMMENT: time-units TYPE: time_t LOC: Config.Timeout.read DEFAULT: 15 minutes DOC_START The read_timeout is applied on server-side connections. After each successful read(), the timeout will be extended by this amount. If no data is read again after this amount of time, the request is aborted and logged with ERR_READ_TIMEOUT. The default is 15 minutes. DOC_END NAME: request_timeout TYPE: time_t LOC: Config.Timeout.request DEFAULT: 5 minutes DOC_START How long to wait for complete HTTP request headers after initial connection establishment. DOC_END NAME: persistent_request_timeout TYPE: time_t LOC: Config.Timeout.persistent_request DEFAULT: 2 minutes DOC_START How long to wait for the next HTTP request on a persistent connection after the previous request completes. DOC_END NAME: client_lifetime COMMENT: time-units TYPE: time_t LOC: Config.Timeout.lifetime DEFAULT: 1 day DOC_START The maximum amount of time a client (browser) is allowed to remain connected to the cache process. This protects the Cache from having a lot of sockets (and hence file descriptors) tied up in a CLOSE_WAIT state from remote clients that go away without properly shutting down (either because of a network failure or because of a poor client implementation). The default is one day, 1440 minutes. NOTE: The default value is intended to be much larger than any client would ever need to be connected to your cache. You should probably change client_lifetime only as a last resort. If you seem to have many client connections tying up filedescriptors, we recommend first tuning the read_timeout, request_timeout, persistent_request_timeout and quick_abort values. DOC_END NAME: half_closed_clients TYPE: onoff LOC: Config.onoff.half_closed_clients DEFAULT: off DOC_START Some clients may shutdown the sending side of their TCP connections, while leaving their receiving sides open. Sometimes, Squid can not tell the difference between a half-closed and a fully-closed TCP connection. By default, Squid will immediately close client connections when read(2) returns "no more data to read." Change this option to 'on' and Squid will keep open connections until a read(2) or write(2) on the socket returns an error. This may show some benefits for reverse proxies. But if not it is recommended to leave OFF. DOC_END NAME: pconn_timeout TYPE: time_t LOC: Config.Timeout.pconn DEFAULT: 1 minute DOC_START Timeout for idle persistent connections to servers and other proxies. DOC_END NAME: ident_timeout TYPE: time_t IFDEF: USE_IDENT LOC: Ident::TheConfig.timeout DEFAULT: 10 seconds DOC_START Maximum time to wait for IDENT lookups to complete. If this is too high, and you enabled IDENT lookups from untrusted users, you might be susceptible to denial-of-service by having many ident requests going at once. DOC_END NAME: shutdown_lifetime COMMENT: time-units TYPE: time_t LOC: Config.shutdownLifetime DEFAULT: 30 seconds DOC_START When SIGTERM or SIGHUP is received, the cache is put into "shutdown pending" mode until all active sockets are closed. This value is the lifetime to set for all open descriptors during shutdown mode. Any active clients after this many seconds will receive a 'timeout' message. DOC_END COMMENT_START ADMINISTRATIVE PARAMETERS ----------------------------------------------------------------------------- COMMENT_END NAME: cache_mgr TYPE: string DEFAULT: webmaster LOC: Config.adminEmail DOC_START Email-address of local cache manager who will receive mail if the cache dies. The default is "webmaster." DOC_END NAME: mail_from TYPE: string DEFAULT: none LOC: Config.EmailFrom DOC_START From: email-address for mail sent when the cache dies. The default is to use 'appname@unique_hostname'. Default appname value is "squid", can be changed into src/globals.h before building squid. DOC_END NAME: mail_program TYPE: eol DEFAULT: mail LOC: Config.EmailProgram DOC_START Email program used to send mail if the cache dies. The default is "mail". The specified program must comply with the standard Unix mail syntax: mail-program recipient < mailfile Optional command line options can be specified. DOC_END NAME: cache_effective_user TYPE: string DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@ LOC: Config.effectiveUser DOC_START If you start Squid as root, it will change its effective/real UID/GID to the user specified below. The default is to change to UID of @DEFAULT_CACHE_EFFECTIVE_USER@. see also; cache_effective_group DOC_END NAME: cache_effective_group TYPE: string DEFAULT: none LOC: Config.effectiveGroup DOC_START Squid sets the GID to the effective user's default group ID (taken from the password file) and supplementary group list from the groups membership. If you want Squid to run with a specific GID regardless of the group memberships of the effective user then set this to the group (or GID) you want Squid to run as. When set all other group privileges of the effective user are ignored and only this GID is effective. If Squid is not started as root the user starting Squid MUST be member of the specified group. This option is not recommended by the Squid Team. Our preference is for administrators to configure a secure user account for squid with UID/GID matching system policies. DOC_END NAME: httpd_suppress_version_string COMMENT: on|off TYPE: onoff DEFAULT: off LOC: Config.onoff.httpd_suppress_version_string DOC_START Suppress Squid version string info in HTTP headers and HTML error pages. DOC_END NAME: visible_hostname TYPE: string LOC: Config.visibleHostname DEFAULT: none DOC_START If you want to present a special hostname in error messages, etc, define this. Otherwise, the return value of gethostname() will be used. If you have multiple caches in a cluster and get errors about IP-forwarding you must set them to have individual names with this setting. DOC_END NAME: unique_hostname TYPE: string LOC: Config.uniqueHostname DEFAULT: none DOC_START If you want to have multiple machines with the same 'visible_hostname' you must give each machine a different 'unique_hostname' so forwarding loops can be detected. DOC_END NAME: hostname_aliases TYPE: wordlist LOC: Config.hostnameAliases DEFAULT: none DOC_START A list of other DNS names your cache has. DOC_END NAME: umask TYPE: int LOC: Config.umask DEFAULT: 027 DOC_START Minimum umask which should be enforced while the proxy is running, in addition to the umask set at startup. For a traditional octal representation of umasks, start your value with 0. DOC_END COMMENT_START OPTIONS FOR THE CACHE REGISTRATION SERVICE ----------------------------------------------------------------------------- This section contains parameters for the (optional) cache announcement service. This service is provided to help cache administrators locate one another in order to join or create cache hierarchies. An 'announcement' message is sent (via UDP) to the registration service by Squid. By default, the announcement message is NOT SENT unless you enable it with 'announce_period' below. The announcement message includes your hostname, plus the following information from this configuration file: http_port icp_port cache_mgr All current information is processed regularly and made available on the Web at http://www.ircache.net/Cache/Tracker/. COMMENT_END NAME: announce_period TYPE: time_t LOC: Config.Announce.period DEFAULT: 0 DOC_START This is how frequently to send cache announcements. The default is `0' which disables sending the announcement messages. To enable announcing your cache, just set an announce period. Example: announce_period 1 day DOC_END NAME: announce_host TYPE: string DEFAULT: tracker.ircache.net LOC: Config.Announce.host DOC_NONE NAME: announce_file TYPE: string DEFAULT: none LOC: Config.Announce.file DOC_NONE NAME: announce_port TYPE: ushort DEFAULT: 3131 LOC: Config.Announce.port DOC_START announce_host and announce_port set the hostname and port number where the registration message will be sent. Hostname will default to 'tracker.ircache.net' and port will default default to 3131. If the 'filename' argument is given, the contents of that file will be included in the announce message. DOC_END COMMENT_START HTTPD-ACCELERATOR OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: httpd_accel_surrogate_id IFDEF: USE_SQUID_ESI TYPE: string LOC: Config.Accel.surrogate_id DEFAULT: unset-id DOC_START Surrogates (http://www.esi.org/architecture_spec_1.0.html) need an identification token to allow control targeting. Because a farm of surrogates may all perform the same tasks, they may share an identification token. DOC_END NAME: http_accel_surrogate_remote IFDEF: USE_SQUID_ESI COMMENT: on|off TYPE: onoff DEFAULT: off LOC: Config.onoff.surrogate_is_remote DOC_START Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote. Set this to on to have squid behave as a remote surrogate. DOC_END NAME: esi_parser IFDEF: USE_SQUID_ESI COMMENT: libxml2|expat|custom TYPE: string LOC: ESIParser::Type DEFAULT: custom DOC_START ESI markup is not strictly XML compatible. The custom ESI parser will give higher performance, but cannot handle non ASCII character encodings. DOC_END COMMENT_START DELAY POOL PARAMETERS ----------------------------------------------------------------------------- COMMENT_END NAME: delay_pools TYPE: delay_pool_count DEFAULT: 0 IFDEF: DELAY_POOLS LOC: Config.Delay DOC_START This represents the number of delay pools to be used. For example, if you have one class 2 delay pool and one class 3 delays pool, you have a total of 2 delay pools. DOC_END NAME: delay_class TYPE: delay_pool_class DEFAULT: none IFDEF: DELAY_POOLS LOC: Config.Delay DOC_START This defines the class of each delay pool. There must be exactly one delay_class line for each delay pool. For example, to define two delay pools, one of class 2 and one of class 3, the settings above and here would be: Example: delay_pools 4 # 4 delay pools delay_class 1 2 # pool 1 is a class 2 pool delay_class 2 3 # pool 2 is a class 3 pool delay_class 3 4 # pool 3 is a class 4 pool delay_class 4 5 # pool 4 is a class 5 pool The delay pool classes are: class 1 Everything is limited by a single aggregate bucket. class 2 Everything is limited by a single aggregate bucket as well as an "individual" bucket chosen from bits 25 through 32 of the IPv4 address. class 3 Everything is limited by a single aggregate bucket as well as a "network" bucket chosen from bits 17 through 24 of the IP address and a "individual" bucket chosen from bits 17 through 32 of the IPv4 address. class 4 Everything in a class 3 delay pool, with an additional limit on a per user basis. This only takes effect if the username is established in advance - by forcing authentication in your http_access rules. class 5 Requests are grouped according their tag (see external_acl's tag= reply). Each pool also requires a delay_parameters directive to configure the pool size and speed limits used whenever the pool is applied to a request. Along with a set of delay_access directives to determine when it is used. NOTE: If an IP address is a.b.c.d -> bits 25 through 32 are "d" -> bits 17 through 24 are "c" -> bits 17 through 32 are "c * 256 + d" NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic. DOC_END NAME: delay_access TYPE: delay_pool_access DEFAULT: none IFDEF: DELAY_POOLS LOC: Config.Delay DOC_START This is used to determine which delay pool a request falls into. delay_access is sorted per pool and the matching starts with pool 1, then pool 2, ..., and finally pool N. The first delay pool where the request is allowed is selected for the request. If it does not allow the request to any pool then the request is not delayed (default). For example, if you want some_big_clients in delay pool 1 and lotsa_little_clients in delay pool 2: Example: delay_access 1 allow some_big_clients delay_access 1 deny all delay_access 2 allow lotsa_little_clients delay_access 2 deny all delay_access 3 allow authenticated_clients DOC_END NAME: delay_parameters TYPE: delay_pool_rates DEFAULT: none IFDEF: DELAY_POOLS LOC: Config.Delay DOC_START This defines the parameters for a delay pool. Each delay pool has a number of "buckets" associated with it, as explained in the description of delay_class. For a class 1 delay pool, the syntax is: delay_pools pool 1 delay_parameters pool aggregate For a class 2 delay pool: delay_pools pool 2 delay_parameters pool aggregate individual For a class 3 delay pool: delay_pools pool 3 delay_parameters pool aggregate network individual For a class 4 delay pool: delay_pools pool 4 delay_parameters pool aggregate network individual user For a class 5 delay pool: delay_pools pool 5 delay_parameters pool tagrate The option variables are: pool a pool number - ie, a number between 1 and the number specified in delay_pools as used in delay_class lines. aggregate the speed limit parameters for the aggregate bucket (class 1, 2, 3). individual the speed limit parameters for the individual buckets (class 2, 3). network the speed limit parameters for the network buckets (class 3). user the speed limit parameters for the user buckets (class 4). tagrate the speed limit parameters for the tag buckets (class 5). A pair of delay parameters is written restore/maximum, where restore is the number of bytes (not bits - modem and network speeds are usually quoted in bits) per second placed into the bucket, and maximum is the maximum number of bytes which can be in the bucket at any time. There must be one delay_parameters line for each delay pool. For example, if delay pool number 1 is a class 2 delay pool as in the above example, and is being used to strictly limit each host to 64Kbit/sec (plus overheads), with no overall limit, the line is: delay_parameters 1 -1/-1 8000/8000 Note that 8 x 8000 KByte/sec -> 64Kbit/sec. Note that the figure -1 is used to represent "unlimited". And, if delay pool number 2 is a class 3 delay pool as in the above example, and you want to limit it to a total of 256Kbit/sec (strict limit) with each 8-bit network permitted 64Kbit/sec (strict limit) and each individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits to permit a decent web page to be downloaded at a decent speed (if the network is not being limited due to overuse) but slow down large downloads more significantly: delay_parameters 2 32000/32000 8000/8000 600/8000 Note that 8 x 32000 KByte/sec -> 256Kbit/sec. 8 x 8000 KByte/sec -> 64Kbit/sec. 8 x 600 Byte/sec -> 4800bit/sec. Finally, for a class 4 delay pool as in the example - each user will be limited to 128Kbits/sec no matter how many workstations they are logged into.: delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000 DOC_END NAME: delay_initial_bucket_level COMMENT: (percent, 0-100) TYPE: ushort DEFAULT: 50 IFDEF: DELAY_POOLS LOC: Config.Delay.initial DOC_START The initial bucket percentage is used to determine how much is put in each bucket when squid starts, is reconfigured, or first notices a host accessing it (in class 2 and class 3, individual hosts and networks only have buckets associated with them once they have been "seen" by squid). DOC_END COMMENT_START WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: wccp_router TYPE: address LOC: Config.Wccp.router DEFAULT: any_addr IFDEF: USE_WCCP DOC_START Use this option to define your WCCP ``home'' router for Squid. wccp_router supports a single WCCP(v1) router wccp2_router supports multiple WCCPv2 routers only one of the two may be used at the same time and defines which version of WCCP to use. DOC_END NAME: wccp2_router TYPE: IpAddress_list LOC: Config.Wccp2.router DEFAULT: none IFDEF: USE_WCCPv2 DOC_START Use this option to define your WCCP ``home'' router for Squid. wccp_router supports a single WCCP(v1) router wccp2_router supports multiple WCCPv2 routers only one of the two may be used at the same time and defines which version of WCCP to use. DOC_END NAME: wccp_version TYPE: int LOC: Config.Wccp.version DEFAULT: 4 IFDEF: USE_WCCP DOC_START This directive is only relevant if you need to set up WCCP(v1) to some very old and end-of-life Cisco routers. In all other setups it must be left unset or at the default setting. It defines an internal version in the WCCP(v1) protocol, with version 4 being the officially documented protocol. According to some users, Cisco IOS 11.2 and earlier only support WCCP version 3. If you're using that or an earlier version of IOS, you may need to change this value to 3, otherwise do not specify this parameter. DOC_END NAME: wccp2_rebuild_wait TYPE: onoff LOC: Config.Wccp2.rebuildwait DEFAULT: on IFDEF: USE_WCCPv2 DOC_START If this is enabled Squid will wait for the cache dir rebuild to finish before sending the first wccp2 HereIAm packet DOC_END NAME: wccp2_forwarding_method TYPE: wccp2_method LOC: Config.Wccp2.forwarding_method DEFAULT: gre IFDEF: USE_WCCPv2 DOC_START WCCP2 allows the setting of forwarding methods between the router/switch and the cache. Valid values are as follows: gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel) l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting) Currently (as of IOS 12.4) cisco routers only support GRE. Cisco switches only support the L2 redirect assignment method. DOC_END NAME: wccp2_return_method TYPE: wccp2_method LOC: Config.Wccp2.return_method DEFAULT: gre IFDEF: USE_WCCPv2 DOC_START WCCP2 allows the setting of return methods between the router/switch and the cache for packets that the cache decides not to handle. Valid values are as follows: gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel) l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting) Currently (as of IOS 12.4) cisco routers only support GRE. Cisco switches only support the L2 redirect assignment. If the "ip wccp redirect exclude in" command has been enabled on the cache interface, then it is still safe for the proxy server to use a l2 redirect method even if this option is set to GRE. DOC_END NAME: wccp2_assignment_method TYPE: wccp2_amethod LOC: Config.Wccp2.assignment_method DEFAULT: hash IFDEF: USE_WCCPv2 DOC_START WCCP2 allows the setting of methods to assign the WCCP hash Valid values are as follows: hash - Hash assignment mask - Mask assignment As a general rule, cisco routers support the hash assignment method and cisco switches support the mask assignment method. DOC_END NAME: wccp2_service TYPE: wccp2_service LOC: Config.Wccp2.info DEFAULT_IF_NONE: standard 0 IFDEF: USE_WCCPv2 DOC_START WCCP2 allows for multiple traffic services. There are two types: "standard" and "dynamic". The standard type defines one service id - http (id 0). The dynamic service ids can be from 51 to 255 inclusive. In order to use a dynamic service id one must define the type of traffic to be redirected; this is done using the wccp2_service_info option. The "standard" type does not require a wccp2_service_info option, just specifying the service id will suffice. MD5 service authentication can be enabled by adding "password=" to the end of this service declaration. Examples: wccp2_service standard 0 # for the 'web-cache' standard service wccp2_service dynamic 80 # a dynamic service type which will be # fleshed out with subsequent options. wccp2_service standard 0 password=foo DOC_END NAME: wccp2_service_info TYPE: wccp2_service_info LOC: Config.Wccp2.info DEFAULT: none IFDEF: USE_WCCPv2 DOC_START Dynamic WCCPv2 services require further information to define the traffic you wish to have diverted. The format is: wccp2_service_info protocol= flags=,.. priority= ports=,.. The relevant WCCPv2 flags: + src_ip_hash, dst_ip_hash + source_port_hash, dst_port_hash + src_ip_alt_hash, dst_ip_alt_hash + src_port_alt_hash, dst_port_alt_hash + ports_source The port list can be one to eight entries. Example: wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source priority=240 ports=80 Note: the service id must have been defined by a previous 'wccp2_service dynamic ' entry. DOC_END NAME: wccp2_weight TYPE: int LOC: Config.Wccp2.weight DEFAULT: 10000 IFDEF: USE_WCCPv2 DOC_START Each cache server gets assigned a set of the destination hash proportional to their weight. DOC_END NAME: wccp_address TYPE: address LOC: Config.Wccp.address DEFAULT: 0.0.0.0 IFDEF: USE_WCCP DOC_NONE NAME: wccp2_address TYPE: address LOC: Config.Wccp2.address DEFAULT: 0.0.0.0 IFDEF: USE_WCCPv2 DOC_START Use this option if you require WCCP to use a specific interface address. The default behavior is to not bind to any specific address. DOC_END COMMENT_START PERSISTENT CONNECTION HANDLING ----------------------------------------------------------------------------- Also see "pconn_timeout" in the TIMEOUTS section COMMENT_END NAME: client_persistent_connections TYPE: onoff LOC: Config.onoff.client_pconns DEFAULT: on DOC_NONE NAME: server_persistent_connections TYPE: onoff LOC: Config.onoff.server_pconns DEFAULT: on DOC_START Persistent connection support for clients and servers. By default, Squid uses persistent connections (when allowed) with its clients and servers. You can use these options to disable persistent connections with clients and/or servers. DOC_END NAME: persistent_connection_after_error TYPE: onoff LOC: Config.onoff.error_pconns DEFAULT: on DOC_START With this directive the use of persistent connections after HTTP errors can be disabled. Useful if you have clients who fail to handle errors on persistent connections proper. DOC_END NAME: detect_broken_pconn TYPE: onoff LOC: Config.onoff.detect_broken_server_pconns DEFAULT: off DOC_START Some servers have been found to incorrectly signal the use of HTTP/1.0 persistent connections even on replies not compatible, causing significant delays. This server problem has mostly been seen on redirects. By enabling this directive Squid attempts to detect such broken replies and automatically assume the reply is finished after 10 seconds timeout. DOC_END COMMENT_START CACHE DIGEST OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: digest_generation IFDEF: USE_CACHE_DIGESTS TYPE: onoff LOC: Config.onoff.digest_generation DEFAULT: on DOC_START This controls whether the server will generate a Cache Digest of its contents. By default, Cache Digest generation is enabled if Squid is compiled with --enable-cache-digests defined. DOC_END NAME: digest_bits_per_entry IFDEF: USE_CACHE_DIGESTS TYPE: int LOC: Config.digest.bits_per_entry DEFAULT: 5 DOC_START This is the number of bits of the server's Cache Digest which will be associated with the Digest entry for a given HTTP Method and URL (public key) combination. The default is 5. DOC_END NAME: digest_rebuild_period IFDEF: USE_CACHE_DIGESTS COMMENT: (seconds) TYPE: time_t LOC: Config.digest.rebuild_period DEFAULT: 1 hour DOC_START This is the wait time between Cache Digest rebuilds. DOC_END NAME: digest_rewrite_period COMMENT: (seconds) IFDEF: USE_CACHE_DIGESTS TYPE: time_t LOC: Config.digest.rewrite_period DEFAULT: 1 hour DOC_START This is the wait time between Cache Digest writes to disk. DOC_END NAME: digest_swapout_chunk_size COMMENT: (bytes) TYPE: b_size_t IFDEF: USE_CACHE_DIGESTS LOC: Config.digest.swapout_chunk_size DEFAULT: 4096 bytes DOC_START This is the number of bytes of the Cache Digest to write to disk at a time. It defaults to 4096 bytes (4KB), the Squid default swap page. DOC_END NAME: digest_rebuild_chunk_percentage COMMENT: (percent, 0-100) IFDEF: USE_CACHE_DIGESTS TYPE: int LOC: Config.digest.rebuild_chunk_percentage DEFAULT: 10 DOC_START This is the percentage of the Cache Digest to be scanned at a time. By default it is set to 10% of the Cache Digest. DOC_END COMMENT_START SNMP OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: snmp_port TYPE: ushort LOC: Config.Port.snmp DEFAULT: 0 IFDEF: SQUID_SNMP DOC_START The port number where Squid listens for SNMP requests. To enable SNMP support set this to a suitable port number. Port number 3401 is often used for the Squid SNMP agent. By default it's set to "0" (disabled) Example: snmp_port 3401 DOC_END NAME: snmp_access TYPE: acl_access LOC: Config.accessList.snmp DEFAULT_IF_NONE: deny all IFDEF: SQUID_SNMP DOC_START Allowing or denying access to the SNMP port. All access to the agent is denied by default. usage: snmp_access allow|deny [!]aclname ... This clause only supports fast acl types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details. Example: snmp_access allow snmppublic localhost snmp_access deny all DOC_END NAME: snmp_incoming_address TYPE: address LOC: Config.Addrs.snmp_incoming DEFAULT: any_addr IFDEF: SQUID_SNMP DOC_NONE NAME: snmp_outgoing_address TYPE: address LOC: Config.Addrs.snmp_outgoing DEFAULT: no_addr IFDEF: SQUID_SNMP DOC_START Just like 'udp_incoming_address', but for the SNMP port. snmp_incoming_address is used for the SNMP socket receiving messages from SNMP agents. snmp_outgoing_address is used for SNMP packets returned to SNMP agents. The default snmp_incoming_address is to listen on all available network interfaces. If snmp_outgoing_address is not set it will use the same socket as snmp_incoming_address. Only change this if you want to have SNMP replies sent using another address than where this Squid listens for SNMP queries. NOTE, snmp_incoming_address and snmp_outgoing_address can not have the same value since they both use port 3401. DOC_END COMMENT_START ICP OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: icp_port udp_port TYPE: ushort DEFAULT: 0 LOC: Config.Port.icp DOC_START The port number where Squid sends and receives ICP queries to and from neighbor caches. The standard UDP port for ICP is 3130. Default is disabled (0). Example: icp_port @DEFAULT_ICP_PORT@ DOC_END NAME: htcp_port IFDEF: USE_HTCP TYPE: ushort DEFAULT: 0 LOC: Config.Port.htcp DOC_START The port number where Squid sends and receives HTCP queries to and from neighbor caches. To turn it on you want to set it to 4827. By default it is set to "0" (disabled). Example: htcp_port 4827 DOC_END NAME: log_icp_queries COMMENT: on|off TYPE: onoff DEFAULT: on LOC: Config.onoff.log_udp DOC_START If set, ICP queries are logged to access.log. You may wish do disable this if your ICP load is VERY high to speed things up or to simplify log analysis. DOC_END NAME: udp_incoming_address TYPE: address LOC:Config.Addrs.udp_incoming DEFAULT: any_addr DOC_START udp_incoming_address is used for UDP packets received from other caches. The default behavior is to not bind to any specific address. Only change this if you want to have all UDP queries received on a specific interface/address. NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS modules. Altering it will affect all of them in the same manner. see also; udp_outgoing_address NOTE, udp_incoming_address and udp_outgoing_address can not have the same value since they both use the same port. DOC_END NAME: udp_outgoing_address TYPE: address LOC: Config.Addrs.udp_outgoing DEFAULT: no_addr DOC_START udp_outgoing_address is used for UDP packets sent out to other caches. The default behavior is to not bind to any specific address. Instead it will use the same socket as udp_incoming_address. Only change this if you want to have UDP queries sent using another address than where this Squid listens for UDP queries from other caches. NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS modules. Altering it will affect all of them in the same manner. see also; udp_incoming_address NOTE, udp_incoming_address and udp_outgoing_address can not have the same value since they both use the same port. DOC_END NAME: icp_hit_stale COMMENT: on|off TYPE: onoff DEFAULT: off LOC: Config.onoff.icp_hit_stale DOC_START If you want to return ICP_HIT for stale cache objects, set this option to 'on'. If you have sibling relationships with caches in other administrative domains, this should be 'off'. If you only have sibling relationships with caches under your control, it is probably okay to set this to 'on'. If set to 'on', your siblings should use the option "allow-miss" on their cache_peer lines for connecting to you. DOC_END NAME: minimum_direct_hops TYPE: int DEFAULT: 4 LOC: Config.minDirectHops DOC_START If using the ICMP pinging stuff, do direct fetches for sites which are no more than this many hops away. DOC_END NAME: minimum_direct_rtt TYPE: int DEFAULT: 400 LOC: Config.minDirectRtt DOC_START If using the ICMP pinging stuff, do direct fetches for sites which are no more than this many rtt milliseconds away. DOC_END NAME: netdb_low TYPE: int DEFAULT: 900 LOC: Config.Netdb.low DOC_NONE NAME: netdb_high TYPE: int DEFAULT: 1000 LOC: Config.Netdb.high DOC_START The low and high water marks for the ICMP measurement database. These are counts, not percents. The defaults are 900 and 1000. When the high water mark is reached, database entries will be deleted until the low mark is reached. DOC_END NAME: netdb_ping_period TYPE: time_t LOC: Config.Netdb.period DEFAULT: 5 minutes DOC_START The minimum period for measuring a site. There will be at least this much delay between successive pings to the same network. The default is five minutes. DOC_END NAME: query_icmp COMMENT: on|off TYPE: onoff DEFAULT: off LOC: Config.onoff.query_icmp DOC_START If you want to ask your peers to include ICMP data in their ICP replies, enable this option. If your peer has configured Squid (during compilation) with '--enable-icmp' that peer will send ICMP pings to origin server sites of the URLs it receives. If you enable this option the ICP replies from that peer will include the ICMP data (if available). Then, when choosing a parent cache, Squid will choose the parent with the minimal RTT to the origin server. When this happens, the hierarchy field of the access.log will be "CLOSEST_PARENT_MISS". This option is off by default. DOC_END NAME: test_reachability COMMENT: on|off TYPE: onoff DEFAULT: off LOC: Config.onoff.test_reachability DOC_START When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH instead of ICP_MISS if the target host is NOT in the ICMP database, or has a zero RTT. DOC_END NAME: icp_query_timeout COMMENT: (msec) DEFAULT: 0 TYPE: int LOC: Config.Timeout.icp_query DOC_START Normally Squid will automatically determine an optimal ICP query timeout value based on the round-trip-time of recent ICP queries. If you want to override the value determined by Squid, set this 'icp_query_timeout' to a non-zero value. This value is specified in MILLISECONDS, so, to use a 2-second timeout (the old default), you would write: icp_query_timeout 2000 DOC_END NAME: maximum_icp_query_timeout COMMENT: (msec) DEFAULT: 2000 TYPE: int LOC: Config.Timeout.icp_query_max DOC_START Normally the ICP query timeout is determined dynamically. But sometimes it can lead to very large values (say 5 seconds). Use this option to put an upper limit on the dynamic timeout value. Do NOT use this option to always use a fixed (instead of a dynamic) timeout value. To set a fixed timeout see the 'icp_query_timeout' directive. DOC_END NAME: minimum_icp_query_timeout COMMENT: (msec) DEFAULT: 5 TYPE: int LOC: Config.Timeout.icp_query_min DOC_START Normally the ICP query timeout is determined dynamically. But sometimes it can lead to very small timeouts, even lower than the normal latency variance on your link due to traffic. Use this option to put an lower limit on the dynamic timeout value. Do NOT use this option to always use a fixed (instead of a dynamic) timeout value. To set a fixed timeout see the 'icp_query_timeout' directive. DOC_END NAME: background_ping_rate COMMENT: time-units TYPE: time_t DEFAULT: 10 seconds LOC: Config.backgroundPingRate DOC_START Controls how often the ICP pings are sent to siblings that have background-ping set. DOC_END COMMENT_START MULTICAST ICP OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: mcast_groups TYPE: wordlist LOC: Config.mcast_group_list DEFAULT: none DOC_START This tag specifies a list of multicast groups which your server should join to receive multicasted ICP queries. NOTE! Be very careful what you put here! Be sure you understand the difference between an ICP _query_ and an ICP _reply_. This option is to be set only if you want to RECEIVE multicast queries. Do NOT set this option to SEND multicast ICP (use cache_peer for that). ICP replies are always sent via unicast, so this option does not affect whether or not you will receive replies from multicast group members. You must be very careful to NOT use a multicast address which is already in use by another group of caches. If you are unsure about multicast, please read the Multicast chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/). Usage: mcast_groups 239.128.16.128 224.0.1.20 By default, Squid doesn't listen on any multicast groups. DOC_END NAME: mcast_miss_addr IFDEF: MULTICAST_MISS_STREAM TYPE: address LOC: Config.mcast_miss.addr DEFAULT: no_addr DOC_START If you enable this option, every "cache miss" URL will be sent out on the specified multicast address. Do not enable this option unless you are are absolutely certain you understand what you are doing. DOC_END NAME: mcast_miss_ttl IFDEF: MULTICAST_MISS_STREAM TYPE: ushort LOC: Config.mcast_miss.ttl DEFAULT: 16 DOC_START This is the time-to-live value for packets multicasted when multicasting off cache miss URLs is enabled. By default this is set to 'site scope', i.e. 16. DOC_END NAME: mcast_miss_port IFDEF: MULTICAST_MISS_STREAM TYPE: ushort LOC: Config.mcast_miss.port DEFAULT: 3135 DOC_START This is the port number to be used in conjunction with 'mcast_miss_addr'. DOC_END NAME: mcast_miss_encode_key IFDEF: MULTICAST_MISS_STREAM TYPE: string LOC: Config.mcast_miss.encode_key DEFAULT: XXXXXXXXXXXXXXXX DOC_START The URLs that are sent in the multicast miss stream are encrypted. This is the encryption key. DOC_END NAME: mcast_icp_query_timeout COMMENT: (msec) DEFAULT: 2000 TYPE: int LOC: Config.Timeout.mcast_icp_query DOC_START For multicast peers, Squid regularly sends out ICP "probes" to count how many other peers are listening on the given multicast address. This value specifies how long Squid should wait to count all the replies. The default is 2000 msec, or 2 seconds. DOC_END COMMENT_START INTERNAL ICON OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: icon_directory TYPE: string LOC: Config.icons.directory DEFAULT: @DEFAULT_ICON_DIR@ DOC_START Where the icons are stored. These are normally kept in @DEFAULT_ICON_DIR@ DOC_END NAME: global_internal_static TYPE: onoff LOC: Config.onoff.global_internal_static DEFAULT: on DOC_START This directive controls is Squid should intercept all requests for /squid-internal-static/ no matter which host the URL is requesting (default on setting), or if nothing special should be done for such URLs (off setting). The purpose of this directive is to make icons etc work better in complex cache hierarchies where it may not always be possible for all corners in the cache mesh to reach the server generating a directory listing. DOC_END NAME: short_icon_urls TYPE: onoff LOC: Config.icons.use_short_names DEFAULT: on DOC_START If this is enabled Squid will use short URLs for icons. If disabled it will revert to the old behavior of including it's own name and port in the URL. If you run a complex cache hierarchy with a mix of Squid and other proxies you may need to disable this directive. DOC_END COMMENT_START ERROR PAGE OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: error_directory TYPE: string LOC: Config.errorDirectory DEFAULT: none DOC_START If you wish to create your own versions of the default error files to customize them to suit your company copy the error/template files to another directory and point this tag at them. WARNING: This option will disable multi-language support on error pages if used. The squid developers are interested in making squid available in a wide variety of languages. If you are making translations for a language that Squid does not currently provide please consider contributing your translation back to the project. http://wiki.squid-cache.org/Translations The squid developers working on translations are happy to supply drop-in translated error files in exchange for any new language contributions. DOC_END NAME: error_default_language IFDEF: USE_ERR_LOCALES TYPE: string LOC: Config.errorDefaultLanguage DEFAULT: none DOC_START Set the default language which squid will send error pages in if no existing translation matches the clients language preferences. If unset (default) generic English will be used. The squid developers are interested in making squid available in a wide variety of languages. If you are interested in making translations for any language see the squid wiki for details. http://wiki.squid-cache.org/Translations DOC_END NAME: error_log_languages IFDEF: USE_ERR_LOCALES TYPE: onoff LOC: Config.errorLogMissingLanguages DEFAULT: on DOC_START Log to cache.log what languages users are attempting to auto-negotiate for translations. Successful negotiations are not logged. Only failures have meaning to indicate that Squid may need an upgrade of its error page translations. DOC_END NAME: err_page_stylesheet TYPE: string LOC: Config.errorStylesheet DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css DOC_START CSS Stylesheet to pattern the display of Squid default error pages. For information on CSS see http://www.w3.org/Style/CSS/ DOC_END NAME: err_html_text TYPE: eol LOC: Config.errHtmlText DEFAULT: none DOC_START HTML text to include in error messages. Make this a "mailto" URL to your admin address, or maybe just a link to your organizations Web page. To include this in your error messages, you must rewrite the error template files (found in the "errors" directory). Wherever you want the 'err_html_text' line to appear, insert a %L tag in the error template file. DOC_END NAME: email_err_data COMMENT: on|off TYPE: onoff LOC: Config.onoff.emailErrData DEFAULT: on DOC_START If enabled, information about the occurred error will be included in the mailto links of the ERR pages (if %W is set) so that the email body contains the data. Syntax is %w DOC_END NAME: deny_info TYPE: denyinfo LOC: Config.denyInfoList DEFAULT: none DOC_START Usage: deny_info err_page_name acl or deny_info http://... acl or deny_info TCP_RESET acl This can be used to return a ERR_ page for requests which do not pass the 'http_access' rules. Squid remembers the last acl it evaluated in http_access, and if a 'deny_info' line exists for that ACL Squid returns a corresponding error page. The acl is typically the last acl on the http_access deny line which denied access. The exceptions to this rule are: - When Squid needs to request authentication credentials. It's then the first authentication related acl encountered - When none of the http_access lines matches. It's then the last acl processed on the last http_access line. NP: If providing your own custom error pages with error_directory you may also specify them by your custom file name: Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys Alternatively you can specify an error URL. The browsers will get redirected (302 or 307) to the specified URL. %s in the redirection URL will be replaced by the requested URL. Alternatively you can tell Squid to reset the TCP connection by specifying TCP_RESET. DOC_END COMMENT_START OPTIONS INFLUENCING REQUEST FORWARDING ----------------------------------------------------------------------------- COMMENT_END NAME: nonhierarchical_direct TYPE: onoff LOC: Config.onoff.nonhierarchical_direct DEFAULT: on DOC_START By default, Squid will send any non-hierarchical requests (matching hierarchy_stoplist or not cacheable request type) direct to origin servers. If you set this to off, Squid will prefer to send these requests to parents. Note that in most configurations, by turning this off you will only add latency to these request without any improvement in global hit ratio. If you are inside an firewall see never_direct instead of this directive. DOC_END NAME: prefer_direct TYPE: onoff LOC: Config.onoff.prefer_direct DEFAULT: off DOC_START Normally Squid tries to use parents for most requests. If you for some reason like it to first try going direct and only use a parent if going direct fails set this to on. By combining nonhierarchical_direct off and prefer_direct on you can set up Squid to use a parent as a backup path if going direct fails. Note: If you want Squid to use parents for all requests see the never_direct directive. prefer_direct only modifies how Squid acts on cacheable requests. DOC_END NAME: always_direct TYPE: acl_access LOC: Config.accessList.AlwaysDirect DEFAULT: none DOC_START Usage: always_direct allow|deny [!]aclname ... Here you can use ACL elements to specify requests which should ALWAYS be forwarded by Squid to the origin servers without using any peers. For example, to always directly forward requests for local servers ignoring any parents or siblings you may have use something like: acl local-servers dstdomain my.domain.net always_direct allow local-servers To always forward FTP requests directly, use acl FTP proto FTP always_direct allow FTP NOTE: There is a similar, but opposite option named 'never_direct'. You need to be aware that "always_direct deny foo" is NOT the same thing as "never_direct allow foo". You may need to use a deny rule to exclude a more-specific case of some other rule. Example: acl local-external dstdomain external.foo.net acl local-servers dstdomain .foo.net always_direct deny local-external always_direct allow local-servers NOTE: If your goal is to make the client forward the request directly to the origin server bypassing Squid then this needs to be done in the client configuration. Squid configuration can only tell Squid how Squid should fetch the object. NOTE: This directive is not related to caching. The replies is cached as usual even if you use always_direct. To not cache the replies see the 'cache' directive. This clause supports both fast and slow acl types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details. DOC_END NAME: never_direct TYPE: acl_access LOC: Config.accessList.NeverDirect DEFAULT: none DOC_START Usage: never_direct allow|deny [!]aclname ... never_direct is the opposite of always_direct. Please read the description for always_direct if you have not already. With 'never_direct' you can use ACL elements to specify requests which should NEVER be forwarded directly to origin servers. For example, to force the use of a proxy for all requests, except those in your local domain use something like: acl local-servers dstdomain .foo.net never_direct deny local-servers never_direct allow all or if Squid is inside a firewall and there are local intranet servers inside the firewall use something like: acl local-intranet dstdomain .foo.net acl local-external dstdomain external.foo.net always_direct deny local-external always_direct allow local-intranet never_direct allow all This clause supports both fast and slow acl types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details. DOC_END COMMENT_START ADVANCED NETWORKING OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: incoming_icp_average TYPE: int DEFAULT: 6 LOC: Config.comm_incoming.icp_average DOC_NONE NAME: incoming_http_average TYPE: int DEFAULT: 4 LOC: Config.comm_incoming.http_average DOC_NONE NAME: incoming_dns_average TYPE: int DEFAULT: 4 LOC: Config.comm_incoming.dns_average DOC_NONE NAME: min_icp_poll_cnt TYPE: int DEFAULT: 8 LOC: Config.comm_incoming.icp_min_poll DOC_NONE NAME: min_dns_poll_cnt TYPE: int DEFAULT: 8 LOC: Config.comm_incoming.dns_min_poll DOC_NONE NAME: min_http_poll_cnt TYPE: int DEFAULT: 8 LOC: Config.comm_incoming.http_min_poll DOC_START Heavy voodoo here. I can't even believe you are reading this. Are you crazy? Don't even think about adjusting these unless you understand the algorithms in comm_select.c first! DOC_END NAME: accept_filter TYPE: string DEFAULT: none LOC: Config.accept_filter DOC_START FreeBSD: The name of an accept(2) filter to install on Squid's listen socket(s). This feature is perhaps specific to FreeBSD and requires support in the kernel. The 'httpready' filter delays delivering new connections to Squid until a full HTTP request has been received. See the accf_http(9) man page for details. The 'dataready' filter delays delivering new connections to Squid until there is some data to process. See the accf_dataready(9) man page for details. Linux: The 'data' filter delays delivering of new connections to Squid until there is some data to process by TCP_ACCEPT_DEFER. You may optionally specify a number of seconds to wait by 'data=N' where N is the number of seconds. Defaults to 30 if not specified. See the tcp(7) man page for details. EXAMPLE: # FreeBSD accept_filter httpready # Linux accept_filter data DOC_END NAME: client_ip_max_connections TYPE: int LOC: Config.client_ip_max_connections DEFAULT: -1 DOC_START Set an absolute limit on the number of connections a single client IP can use. Any more than this and Squid will begin to drop new connections from the client until it closes some links. Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP connections from the client. For finer control use the ACL access controls. Requires client_db to be enabled (the default). WARNING: This may noticably slow down traffic received via external proxies or NAT devices and cause them to rebound error messages back to their clients. DOC_END NAME: tcp_recv_bufsize COMMENT: (bytes) TYPE: b_size_t DEFAULT: 0 bytes LOC: Config.tcpRcvBufsz DOC_START Size of receive buffer to set for TCP sockets. Probably just as easy to change your kernel's default. Set to zero to use the default buffer size. DOC_END COMMENT_START ICAP OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: icap_enable TYPE: onoff IFDEF: ICAP_CLIENT COMMENT: on|off LOC: Adaptation::Icap::TheConfig.onoff DEFAULT: off DOC_START If you want to enable the ICAP module support, set this to on. DOC_END NAME: icap_connect_timeout TYPE: time_t DEFAULT: none LOC: Adaptation::Icap::TheConfig.connect_timeout_raw IFDEF: ICAP_CLIENT DOC_START This parameter specifies how long to wait for the TCP connect to the requested ICAP server to complete before giving up and either terminating the HTTP transaction or bypassing the failure. The default for optional services is peer_connect_timeout. The default for essential services is connect_timeout. If this option is explicitly set, its value applies to all services. DOC_END NAME: icap_io_timeout COMMENT: time-units TYPE: time_t DEFAULT: none LOC: Adaptation::Icap::TheConfig.io_timeout_raw IFDEF: ICAP_CLIENT DOC_START This parameter specifies how long to wait for an I/O activity on an established, active ICAP connection before giving up and either terminating the HTTP transaction or bypassing the failure. The default is read_timeout. DOC_END NAME: icap_service_failure_limit TYPE: int IFDEF: ICAP_CLIENT LOC: Adaptation::Icap::TheConfig.service_failure_limit DEFAULT: 10 DOC_START The limit specifies the number of failures that Squid tolerates when establishing a new TCP connection with an ICAP service. If the number of failures exceeds the limit, the ICAP service is not used for new ICAP requests until it is time to refresh its OPTIONS. The per-service failure counter is reset to zero each time Squid fetches new service OPTIONS. A negative value disables the limit. Without the limit, an ICAP service will not be considered down due to connectivity failures between ICAP OPTIONS requests. DOC_END NAME: icap_service_revival_delay TYPE: int IFDEF: ICAP_CLIENT LOC: Adaptation::Icap::TheConfig.service_revival_delay DEFAULT: 180 DOC_START The delay specifies the number of seconds to wait after an ICAP OPTIONS request failure before requesting the options again. The failed ICAP service is considered "down" until fresh OPTIONS are fetched. The actual delay cannot be smaller than the hardcoded minimum delay of 30 seconds. DOC_END NAME: icap_preview_enable TYPE: onoff IFDEF: ICAP_CLIENT COMMENT: on|off LOC: Adaptation::Icap::TheConfig.preview_enable DEFAULT: on DOC_START The ICAP Preview feature allows the ICAP server to handle the HTTP message by looking only at the beginning of the message body or even without receiving the body at all. In some environments, previews greatly speedup ICAP processing. During an ICAP OPTIONS transaction, the server may tell Squid what HTTP messages should be previewed and how big the preview should be. Squid will not use Preview if the server did not request one. To disable ICAP Preview for all ICAP services, regardless of individual ICAP server OPTIONS responses, set this option to "off". Example: icap_preview_enable off DOC_END NAME: icap_preview_size TYPE: int IFDEF: ICAP_CLIENT LOC: Adaptation::Icap::TheConfig.preview_size DEFAULT: -1 DOC_START The default size of preview data to be sent to the ICAP server. -1 means no preview. This value might be overwritten on a per server basis by OPTIONS requests. DOC_END NAME: icap_default_options_ttl TYPE: int IFDEF: ICAP_CLIENT LOC: Adaptation::Icap::TheConfig.default_options_ttl DEFAULT: 60 DOC_START The default TTL value for ICAP OPTIONS responses that don't have an Options-TTL header. DOC_END NAME: icap_persistent_connections TYPE: onoff IFDEF: ICAP_CLIENT COMMENT: on|off LOC: Adaptation::Icap::TheConfig.reuse_connections DEFAULT: on DOC_START Whether or not Squid should use persistent connections to an ICAP server. DOC_END NAME: icap_send_client_ip TYPE: onoff IFDEF: ICAP_CLIENT COMMENT: on|off LOC: Adaptation::Icap::TheConfig.send_client_ip DEFAULT: off DOC_START If enabled, Squid shares HTTP client IP information with adaptation services. For ICAP, Squid adds the X-Client-IP header to ICAP requests. For eCAP, Squid sets the libecap::metaClientIp transaction option. See also: adaptation_uses_indirect_client DOC_END NAME: icap_send_client_username TYPE: onoff IFDEF: ICAP_CLIENT COMMENT: on|off LOC: Adaptation::Icap::TheConfig.send_client_username DEFAULT: off DOC_START This sends authenticated HTTP client username (if available) to the ICAP service. The username value is encoded based on the icap_client_username_encode option and is sent using the header specified by the icap_client_username_header option. DOC_END NAME: icap_client_username_header TYPE: string IFDEF: ICAP_CLIENT LOC: Adaptation::Icap::TheConfig.client_username_header DEFAULT: X-Client-Username DOC_START ICAP request header name to use for send_client_username. DOC_END NAME: icap_client_username_encode TYPE: onoff IFDEF: ICAP_CLIENT COMMENT: on|off LOC: Adaptation::Icap::TheConfig.client_username_encode DEFAULT: off DOC_START Whether to base64 encode the authenticated client username. DOC_END NAME: icap_service TYPE: icap_service_type IFDEF: ICAP_CLIENT LOC: Adaptation::Icap::TheConfig DEFAULT: none DOC_START Defines a single ICAP service using the following format: icap_service service_name vectoring_point [options] service_url service_name: ID an opaque identifier which must be unique in squid.conf vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache This specifies at which point of transaction processing the ICAP service should be activated. *_postcache vectoring points are not yet supported. service_url: icap://servername:port/servicepath ICAP server and service location. ICAP does not allow a single service to handle both REQMOD and RESPMOD transactions. Squid does not enforce that requirement. You can specify services with the same service_url and different vectoring_points. You can even specify multiple identical services as long as their service_names differ. Service options are separated by white space. ICAP services support the following name=value options: bypass=on|off|1|0 If set to 'on' or '1', the ICAP service is treated as optional. If the service cannot be reached or malfunctions, Squid will try to ignore any errors and process the message as if the service was not enabled. No all ICAP errors can be bypassed. If set to 0, the ICAP service is treated as essential and all ICAP errors will result in an error page returned to the HTTP client. Bypass is off by default: services are treated as essential. routing=on|off|1|0 If set to 'on' or '1', the ICAP service is allowed to dynamically change the current message adaptation plan by returning a chain of services to be used next. The services are specified using the X-Next-Services ICAP response header value, formatted as a comma-separated list of service names. Each named service should be configured in squid.conf and should have the same method and vectoring point as the current ICAP transaction. Services violating these rules are ignored. An empty X-Next-Services value results in an empty plan which ends the current adaptation. Routing is not allowed by default: the ICAP X-Next-Services response header is ignored. ipv6=on|off Only has effect on split-stack systems. The default on those systems is to use IPv4-only connections. When set to 'on' this option will make Squid use IPv6-only connections to contact this ICAP service. Older icap_service format without optional named parameters is deprecated but supported for backward compatibility. Example: icap_service svcBlocker reqmod_precache bypass=0 icap://icap1.mydomain.net:1344/reqmod icap_service svcLogger reqmod_precache routing=on icap://icap2.mydomain.net:1344/respmod DOC_END NAME: icap_class TYPE: icap_class_type IFDEF: ICAP_CLIENT LOC: none DEFAULT: none DOC_START This deprecated option was documented to define an ICAP service chain, even though it actually defined a set of similar, redundant services, and the chains were not supported. To define a set of redundant services, please use the adaptation_service_set directive. For service chains, use adaptation_service_chain. DOC_END NAME: icap_access TYPE: icap_access_type IFDEF: ICAP_CLIENT LOC: none DEFAULT: none DOC_START This option is deprecated. Please use adaptation_access, which has the same ICAP functionality, but comes with better documentation, and eCAP support. DOC_END COMMENT_START eCAP OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: ecap_enable TYPE: onoff IFDEF: USE_ECAP COMMENT: on|off LOC: Adaptation::Ecap::TheConfig.onoff DEFAULT: off DOC_START Controls whether eCAP support is enabled. DOC_END NAME: ecap_service TYPE: ecap_service_type IFDEF: USE_ECAP LOC: Adaptation::Ecap::TheConfig DEFAULT: none DOC_START Defines a single eCAP service ecap_service servicename vectoring_point bypass service_url vectoring_point = reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache This specifies at which point of transaction processing the eCAP service should be activated. *_postcache vectoring points are not yet supported. bypass = 1|0 If set to 1, the eCAP service is treated as optional. If the service cannot be reached or malfunctions, Squid will try to ignore any errors and process the message as if the service was not enabled. No all eCAP errors can be bypassed. If set to 0, the eCAP service is treated as essential and all eCAP errors will result in an error page returned to the HTTP client. service_url = ecap://vendor/service_name?custom&cgi=style¶meters=optional Example: ecap_service service_1 reqmod_precache 0 ecap://filters-R-us/leakDetector?on_error=block ecap_service service_2 respmod_precache 1 icap://filters-R-us/virusFilter?config=/etc/vf.cfg DOC_END NAME: loadable_modules TYPE: wordlist IFDEF: USE_LOADABLE_MODULES LOC: Config.loadable_module_names DEFAULT: none DOC_START Instructs Squid to load the specified dynamic module(s) or activate preloaded module(s). Example: loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so DOC_END COMMENT_START MESSAGE ADAPTATION OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: adaptation_service_set TYPE: adaptation_service_set_type IFDEF: USE_ADAPTATION LOC: none DEFAULT: none DOC_START Configures an ordered set of similar, redundant services. This is useful when hot standby or backup adaptation servers are available. adaptation_service_set set_name service_name1 service_name2 ... The named services are used in the set declaration order. The first applicable adaptation service from the set is used first. The next applicable service is tried if and only if the transaction with the previous service fails and the message waiting to be adapted is still intact. When adaptation starts, broken services are ignored as if they were not a part of the set. A broken service is a down optional service. The services in a set must be attached to the same vectoring point (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD). If all services in a set are optional then adaptation failures are bypassable. If all services in the set are essential, then a transaction failure with one service may still be retried using another service from the set, but when all services fail, the master transaction fails as well. A set may contain a mix of optional and essential services, but that is likely to lead to surprising results because broken services become ignored (see above), making previously bypassable failures fatal. Technically, it is the bypassability of the last failed service that matters. See also: adaptation_access adaptation_service_chain Example: adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup adaptation service_set svcLogger loggerLocal loggerRemote DOC_END NAME: adaptation_service_chain TYPE: adaptation_service_chain_type IFDEF: USE_ADAPTATION LOC: none DEFAULT: none DOC_START Configures a list of complementary services that will be applied one-by-one, forming an adaptation chain or pipeline. This is useful when Squid must perform different adaptations on the same message. adaptation_service_chain chain_name service_name1 svc_name2 ... The named services are used in the chain declaration order. The first applicable adaptation service from the chain is used first. The next applicable service is applied to the successful adaptation results of the previous service in the chain. When adaptation starts, broken services are ignored as if they were not a part of the chain. A broken service is a down optional service. Request satisfaction terminates the adaptation chain because Squid does not currently allow declaration of RESPMOD services at the "reqmod_precache" vectoring point (see icap_service or ecap_service). The services in a chain must be attached to the same vectoring point (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD). A chain may contain a mix of optional and essential services. If an essential adaptation fails (or the failure cannot be bypassed for other reasons), the master transaction fails. Otherwise, the failure is bypassed as if the failed adaptation service was not in the chain. See also: adaptation_access adaptation_service_set Example: adaptation_service_chain svcRequest requestLogger urlFilter leakDetector DOC_END NAME: adaptation_access TYPE: adaptation_access_type IFDEF: USE_ADAPTATION LOC: none DEFAULT: none DOC_START Sends an HTTP transaction to an ICAP or eCAP adaptation service. adaptation_access service_name allow|deny [!]aclname... adaptation_access set_name allow|deny [!]aclname... At each supported vectoring point, the adaptation_access statements are processed in the order they appear in this configuration file. Statements pointing to the following services are ignored (i.e., skipped without checking their ACL): - services serving different vectoring points - "broken-but-bypassable" services - "up" services configured to ignore such transactions (e.g., based on the ICAP Transfer-Ignore header). When a set_name is used, all services in the set are checked using the same rules, to find the first applicable one. See adaptation_service_set for details. If an access list is checked and there is a match, the processing stops: For an "allow" rule, the corresponding adaptation service is used for the transaction. For a "deny" rule, no adaptation service is activated. It is currently not possible to apply more than one adaptation service at the same vectoring point to the same HTTP transaction. See also: icap_service and ecap_service Example: adaptation_access service_1 allow all DOC_END NAME: adaptation_service_iteration_limit TYPE: int IFDEF: USE_ADAPTATION LOC: Adaptation::Config::service_iteration_limit DEFAULT: 16 DOC_START Limits the number of iterations allowed when applying adaptation services to a message. If your longest adaptation set or chain may have more than 16 services, increase the limit beyond its default value of 16. If detecting infinite iteration loops sooner is critical, make the iteration limit match the actual number of services in your longest adaptation set or chain. Infinite adaptation loops are most likely with routing services. See also: icap_service routing=1 DOC_END NAME: adaptation_masterx_shared_names TYPE: string IFDEF: USE_ADAPTATION LOC: Adaptation::Config::masterx_shared_name DEFAULT: none DOC_START For each master transaction (i.e., the HTTP request and response sequence, including all related ICAP and eCAP exchanges), Squid maintains a table of metadata. The table entries are (name, value) pairs shared among eCAP and ICAP exchanges. The table is destroyed with the master transaction. This option specifies the table entry names that Squid must accept from and forward to the adaptation transactions. An ICAP REQMOD or RESPMOD transaction may set an entry in the shared table by returning an ICAP header field with a name specified in adaptation_masterx_shared_names. Squid will store and forward that ICAP header field to subsequent ICAP transactions within the same master transaction scope. Only one shared entry name is supported at this time. Example: # share authentication information among ICAP services adaptation_masterx_shared_names X-Subscriber-ID DOC_END NAME: icap_retry TYPE: acl_access IFDEF: ICAP_CLIENT LOC: Adaptation::Icap::TheConfig.repeat DEFAULT_IF_NONE: deny all DOC_START This ACL determines which retriable ICAP transactions are retried. Transactions that received a complete ICAP response and did not have to consume or produce HTTP bodies to receive that response are usually retriable. icap_retry allow|deny [!]aclname ... Squid automatically retries some ICAP I/O timeouts and errors due to persistent connection race conditions. See also: icap_retry_limit DOC_END NAME: icap_retry_limit TYPE: int IFDEF: ICAP_CLIENT LOC: Adaptation::Icap::TheConfig.repeat_limit DEFAULT: 0 DOC_START Limits the number of retries allowed. When set to zero (default), no retries are allowed. Communication errors due to persistent connection race conditions are unavoidable, automatically retried, and do not count against this limit. See also: icap_retry DOC_END COMMENT_START DNS OPTIONS ----------------------------------------------------------------------------- COMMENT_END NAME: check_hostnames TYPE: onoff DEFAULT: off LOC: Config.onoff.check_hostnames DOC_START For security and stability reasons Squid can check hostnames for Internet standard RFC compliance. If you want Squid to perform these checks turn this directive on. DOC_END NAME: allow_underscore TYPE: onoff DEFAULT: on LOC: Config.onoff.allow_underscore DOC_START Underscore characters is not strictly allowed in Internet hostnames but nevertheless used by many sites. Set this to off if you want Squid to be strict about the standard. This check is performed only when check_hostnames is set to on. DOC_END NAME: cache_dns_program TYPE: string IFDEF: USE_DNSSERVERS DEFAULT: @DEFAULT_DNSSERVER@ LOC: Config.Program.dnsserver DOC_START Specify the location of the executable for dnslookup process. DOC_END NAME: dns_children TYPE: int IFDEF: USE_DNSSERVERS DEFAULT: 5 LOC: Config.dnsChildren DOC_START The number of processes spawn to service DNS name lookups. For heavily loaded caches on large servers, you should probably increase this value to at least 10. The maximum is 32. The default is 5. You must have at least one dnsserver process. DOC_END NAME: dns_retransmit_interval TYPE: time_t DEFAULT: 5 seconds LOC: Config.Timeout.idns_retransmit IFDEF: !USE_DNSSERVERS DOC_START Initial retransmit interval for DNS queries. The interval is doubled each time all configured DNS servers have been tried. DOC_END NAME: dns_timeout TYPE: time_t DEFAULT: 2 minutes LOC: Config.Timeout.idns_query IFDEF: !USE_DNSSERVERS DOC_START DNS Query timeout. If no response is received to a DNS query within this time all DNS servers for the queried domain are assumed to be unavailable. DOC_END NAME: dns_defnames COMMENT: on|off TYPE: onoff DEFAULT: off LOC: Config.onoff.res_defnames DOC_START Normally the RES_DEFNAMES resolver option is disabled (see res_init(3)). This prevents caches in a hierarchy from interpreting single-component hostnames locally. To allow Squid to handle single-component names, enable this option. DOC_END NAME: dns_nameservers TYPE: wordlist DEFAULT: none LOC: Config.dns_nameservers DOC_START Use this if you want to specify a list of DNS name servers (IP addresses) to use instead of those given in your /etc/resolv.conf file. On Windows platforms, if no value is specified here or in the /etc/resolv.conf file, the list of DNS name servers are taken from the Windows registry, both static and dynamic DHCP configurations are supported. Example: dns_nameservers 10.0.0.1 192.172.0.4 DOC_END NAME: hosts_file TYPE: string DEFAULT: @DEFAULT_HOSTS@ LOC: Config.etcHostsPath DOC_START Location of the host-local IP name-address associations database. Most Operating Systems have such a file on different default locations: - Un*X & Linux: /etc/hosts - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts (%SystemRoot% value install default is c:\winnt) - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts (%SystemRoot% value install default is c:\windows) - Windows 9x/Me: %windir%\hosts (%windir% value is usually c:\windows) - Cygwin: /etc/hosts The file contains newline-separated definitions, in the form ip_address_in_dotted_form name [name ...] names are whitespace-separated. Lines beginning with an hash (#) character are comments. The file is checked at startup and upon configuration. If set to 'none', it won't be checked. If append_domain is used, that domain will be added to domain-local (i.e. not containing any dot character) host definitions. DOC_END NAME: append_domain TYPE: string LOC: Config.appendDomain DEFAULT: none DOC_START Appends local domain name to hostnames without any dots in them. append_domain must begin with a period. Be warned there are now Internet names with no dots in them using only top-domain names, so setting this may cause some Internet sites to become unavailable. Example: append_domain .yourdomain.com DOC_END NAME: ignore_unknown_nameservers TYPE: onoff LOC: Config.onoff.ignore_unknown_nameservers DEFAULT: on IFDEF: !USE_DNSSERVERS DOC_START By default Squid checks that DNS responses are received from the same IP addresses they are sent to. If they don't match, Squid ignores the response and writes a warning message to cache.log. You can allow responses from unknown nameservers by setting this option to 'off'. DOC_END NAME: dns_v4_fallback TYPE: onoff DEFAULT: on LOC: Config.onoff.dns_require_A IFDEF: !USE_DNSSERVERS DOC_START Standard practice with DNS is to lookup either A or AAAA records and use the results if it succeeds. Only looking up the other if the first attempt fails or otherwise produces no results. That policy however will cause squid to produce error pages for some servers that advertise AAAA but are unreachable over IPv6. If this is ON squid will always lookup both AAAA and A, using both. If this is OFF squid will lookup AAAA and only try A if none found. WARNING: There are some possibly unwanted side-effects with this on: *) Doubles the load placed by squid on the DNS network. *) May negatively impact connection delay times. DOC_END NAME: dns_v4_first TYPE: onoff DEFAULT: off LOC: Config.dns.v4_first IFDEF: !USE_DNSSERVERS DOC_START With the IPv6 Internet being as fast or faster than IPv4 Internet for most networks Squid prefers to contact websites over IPv6. This option reverses the order of preference to make Squid contact dual-stack websites over IPv4 first. Squid will still perform both IPv6 and IPv4 DNS lookups before connecting. WARNING: This option will restrict the situations under which IPv6 connectivity is used (and tested). Hiding network problems which would otherwise be detected and warned about. DOC_END NAME: ipcache_size COMMENT: (number of entries) TYPE: int DEFAULT: 1024 LOC: Config.ipcache.size DOC_NONE NAME: ipcache_low COMMENT: (percent) TYPE: int DEFAULT: 90 LOC: Config.ipcache.low DOC_NONE NAME: ipcache_high COMMENT: (percent) TYPE: int DEFAULT: 95 LOC: Config.ipcache.high DOC_START The size, low-, and high-water marks for the IP cache. DOC_END NAME: fqdncache_size COMMENT: (number of entries) TYPE: int DEFAULT: 1024 LOC: Config.fqdncache.size DOC_START Maximum number of FQDN cache entries. DOC_END COMMENT_START MISCELLANEOUS ----------------------------------------------------------------------------- COMMENT_END NAME: memory_pools COMMENT: on|off TYPE: onoff DEFAULT: on LOC: Config.onoff.mem_pools DOC_START If set, Squid will keep pools of allocated (but unused) memory available for future use. If memory is a premium on your system and you believe your malloc library outperforms Squid routines, disable this. DOC_END NAME: memory_pools_limit COMMENT: (bytes) TYPE: b_int64_t DEFAULT: 5 MB LOC: Config.MemPools.limit DOC_START Used only with memory_pools on: memory_pools_limit 50 MB If set to a non-zero value, Squid will keep at most the specified limit of allocated (but unused) memory in memory pools. All free() requests that exceed this limit will be handled by your malloc library. Squid does not pre-allocate any memory, just safe-keeps objects that otherwise would be free()d. Thus, it is safe to set memory_pools_limit to a reasonably high value even if your configuration will use less memory. If set to none, Squid will keep all memory it can. That is, there will be no limit on the total amount of memory used for safe-keeping. To disable memory allocation optimization, do not set memory_pools_limit to 0 or none. Set memory_pools to "off" instead. An overhead for maintaining memory pools is not taken into account when the limit is checked. This overhead is close to four bytes per object kept. However, pools may actually _save_ memory because of reduced memory thrashing in your malloc library. DOC_END NAME: forwarded_for COMMENT: on|off|transparent|truncate|delete TYPE: string DEFAULT: on LOC: opt_forwarded_for DOC_START If set to "on", Squid will append your client's IP address in the HTTP requests it forwards. By default it looks like: X-Forwarded-For: 192.1.2.3 If set to "off", it will appear as X-Forwarded-For: unknown If set to "transparent", Squid will not alter the X-Forwarded-For header in any way. If set to "delete", Squid will delete the entire X-Forwarded-For header. If set to "truncate", Squid will remove all existing X-Forwarded-For entries, and place itself as the sole entry. DOC_END NAME: cachemgr_passwd TYPE: cachemgrpasswd DEFAULT: none LOC: Config.passwd_list DOC_START Specify passwords for cachemgr operations. Usage: cachemgr_passwd password action action ... Some valid actions are (see cache manager menu for a full list): 5min 60min asndb authenticator cbdata client_list comm_incoming config * counters delay digest_stats dns events filedescriptors fqdncache histograms http_headers info io ipcache mem menu netdb non_peers objects offline_toggle * pconn peer_select reconfigure * redirector refresh server_list shutdown * store_digest storedir utilization via_headers vm_objects * Indicates actions which will not be performed without a valid password, others can be performed if not listed here. To disable an action, set the password to "disable". To allow performing an action without a password, set the password to "none". Use the keyword "all" to set the same password for all actions. Example: cachemgr_passwd secret shutdown cachemgr_passwd lesssssssecret info stats/objects cachemgr_passwd disable all DOC_END NAME: client_db COMMENT: on|off TYPE: onoff DEFAULT: on LOC: Config.onoff.client_db DOC_START If you want to disable collecting per-client statistics, turn off client_db here. DOC_END NAME: refresh_all_ims COMMENT: on|off TYPE: onoff DEFAULT: off LOC: Config.onoff.refresh_all_ims DOC_START When you enable this option, squid will always check the origin server for an update when a client sends an If-Modified-Since request. Many browsers use IMS requests when the user requests a reload, and this ensures those clients receive the latest version. By default (off), squid may return a Not Modified response based on the age of the cached version. DOC_END NAME: reload_into_ims IFDEF: HTTP_VIOLATIONS COMMENT: on|off TYPE: onoff DEFAULT: off LOC: Config.onoff.reload_into_ims DOC_START When you enable this option, client no-cache or ``reload'' requests will be changed to If-Modified-Since requests. Doing this VIOLATES the HTTP standard. Enabling this feature could make you liable for problems which it causes. see also refresh_pattern for a more selective approach. DOC_END NAME: maximum_single_addr_tries TYPE: int LOC: Config.retry.maxtries DEFAULT: 1 DOC_START This sets the maximum number of connection attempts for a host that only has one address (for multiple-address hosts, each address is tried once). The default value is one attempt, the (not recommended) maximum is 255 tries. A warning message will be generated if it is set to a value greater than ten. Note: This is in addition to the request re-forwarding which takes place if Squid fails to get a satisfying response. DOC_END NAME: retry_on_error TYPE: onoff LOC: Config.retry.onerror DEFAULT: off DOC_START If set to ON Squid will automatically retry requests when receiving an error response with status 403 (Forbidden), 500 (Internal Error), 501 or 503 (Service not available). Status 502 and 504 (Gateway errors) are always retried. This is mainly useful if you are in a complex cache hierarchy to work around access control errors. NOTE: This retry will attempt to find another working destination. Which is different from the server which just failed. DOC_END NAME: as_whois_server TYPE: string LOC: Config.as_whois_server DEFAULT: whois.ra.net DOC_START WHOIS server to query for AS numbers. NOTE: AS numbers are queried only when Squid starts up, not for every request. DOC_END NAME: offline_mode TYPE: onoff LOC: Config.onoff.offline DEFAULT: off DOC_START Enable this option and Squid will never try to validate cached objects. DOC_END NAME: uri_whitespace TYPE: uri_whitespace LOC: Config.uri_whitespace DEFAULT: strip DOC_START What to do with requests that have whitespace characters in the URI. Options: strip: The whitespace characters are stripped out of the URL. This is the behavior recommended by RFC2396. deny: The request is denied. The user receives an "Invalid Request" message. allow: The request is allowed and the URI is not changed. The whitespace characters remain in the URI. Note the whitespace is passed to redirector processes if they are in use. encode: The request is allowed and the whitespace characters are encoded according to RFC1738. This could be considered a violation of the HTTP/1.1 RFC because proxies are not allowed to rewrite URI's. chop: The request is allowed and the URI is chopped at the first whitespace. This might also be considered a violation. DOC_END NAME: chroot TYPE: string LOC: Config.chroot_dir DEFAULT: none DOC_START Specifies a directory where Squid should do a chroot() while initializing. This also causes Squid to fully drop root privileges after initializing. This means, for example, if you use a HTTP port less than 1024 and try to reconfigure, you may get an error saying that Squid can not open the port. DOC_END NAME: balance_on_multiple_ip TYPE: onoff LOC: Config.onoff.balance_on_multiple_ip DEFAULT: off DOC_START Modern IP resolvers in squid sort lookup results by preferred access. By default squid will use these IP in order and only rotates to the next listed when the most preffered fails. Some load balancing servers based on round robin DNS have been found not to preserve user session state across requests to different IP addresses. Enabling this directive Squid rotates IP's per request. DOC_END NAME: pipeline_prefetch TYPE: onoff LOC: Config.onoff.pipeline_prefetch DEFAULT: off DOC_START To boost the performance of pipelined requests to closer match that of a non-proxied environment Squid can try to fetch up to two requests in parallel from a pipeline. Defaults to off for bandwidth management and access logging reasons. WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication. DOC_END NAME: high_response_time_warning TYPE: int COMMENT: (msec) LOC: Config.warnings.high_rptm DEFAULT: 0 DOC_START If the one-minute median response time exceeds this value, Squid prints a WARNING with debug level 0 to get the administrators attention. The value is in milliseconds. DOC_END NAME: high_page_fault_warning TYPE: int LOC: Config.warnings.high_pf DEFAULT: 0 DOC_START If the one-minute average page fault rate exceeds this value, Squid prints a WARNING with debug level 0 to get the administrators attention. The value is in page faults per second. DOC_END NAME: high_memory_warning TYPE: b_size_t LOC: Config.warnings.high_memory DEFAULT: 0 KB DOC_START If the memory usage (as determined by mallinfo) exceeds this amount, Squid prints a WARNING with debug level 0 to get the administrators attention. DOC_END NAME: sleep_after_fork COMMENT: (microseconds) TYPE: int LOC: Config.sleep_after_fork DEFAULT: 0 DOC_START When this is set to a non-zero value, the main Squid process sleeps the specified number of microseconds after a fork() system call. This sleep may help the situation where your system reports fork() failures due to lack of (virtual) memory. Note, however, if you have a lot of child processes, these sleep delays will add up and your Squid will not service requests for some amount of time until all the child processes have been started. On Windows value less then 1000 (1 milliseconds) are rounded to 1000. DOC_END NAME: windows_ipaddrchangemonitor COMMENT: on|off TYPE: onoff DEFAULT: on LOC: Config.onoff.WIN32_IpAddrChangeMonitor DOC_START On Windows Squid by default will monitor IP address changes and will reconfigure itself after any detected event. This is very useful for proxies connected to internet with dial-up interfaces. In some cases (a Proxy server acting as VPN gateway is one) it could be desiderable to disable this behaviour setting this to 'off'. Note: after changing this, Squid service must be restarted. DOC_END NAME: max_filedescriptors max_filedesc TYPE: int DEFAULT: 0 LOC: Config.max_filedescriptors DOC_START The maximum number of filedescriptors supported. The default "0" means Squid inherits the current ulimit setting. Note: Changing this requires a restart of Squid. Also not all comm loops supports large values. DOC_END EOF .