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Disclaimer: This manual is NOT a Squid tutorial. It is only a reference material that provides detailed explanation of all configuration parameters available in Squid 2.6. The reader is expected to have prior knowledge of basic Squid installation and configuration. For Complete tutorial on Squid, please visit http://www.squid-cache.org

Squid 2.6 Configuration Manual MISCELLANEOUS This section covers configurations that could not be explicitly bundled in with any of the previous categories. Examples of features covered here are limiting the growth of log files, displaying customized information to clients upon error conditions or access denial, defining memory pools for Squid, network management by enabling SNMP, co-ordination with neighbor caches by enabling WCCP, directing the requests either to the origin server or to the neighbor cache, etc. dns_testnames logfile_rotate append_domain tcp_recv_bufsize error_map err_html_text deny_info memory_pools memory_pools_limit via forwarded_for log_icp_queries icp_hit_stale minimum_direct_hops minimum_direct_rtt cachemgr_passwd store_avg_object_size store_objects_per_bucket client_db netdb_low netdb_high netdb_ping_period query_icmp test_reachability buffered_logs reload_into_ims always_direct never_direct header_access header_replace icon_directory global_internal_static short_icon_urls error_directory maximum_single_addr_tries retry_on_error snmp_port snmp_access snmp_incoming_address snmp_outgoing_address as_whois_server wccp_router wccp2_router wccp_version wccp2_rebuild_wait wccp2_forwarding_method wccp2_return_method wccp2_assignment_method wccp2_service wccp2_service_info wccp2_weight wccp_address wccp2_address

TAG NAME                   dns_testnames Description  This points to a number of hosts that Squid can use to test if DNS service is working properly on your network Build Option  Default Usage  dns_testnames url  Default  dns_testnames netscape.com internic.net nlanr.net microsoft.com Synopsis If DNS isn't working properly, Squid will not be able to service requests, so it will refuse to start, with a brief message regarding why in the cache.log. It is recommended that you select two or more host names on the internet and one or two host names on your intranet, assuming you have one and Squid is expected to service it. By default, the  dns_testnames directive checks a few well known and popular sites: netscape.com, internic.net, nlanr.net, and microsoft.com. Arguments url  Sites on which DNS test to be done Example(s) dns_testnames visolve.com       TAG NAME                   logfile_rotate Description  Used to specify the number of old rotated log files Squid will keep Build Option  Default Usage  logfile_rotate number Default  logfile_rotate 10 Synopsis The value in this tag defines number of rotated log files to be generated. This defaults to 10, which means Squid will keep 10 old log files before overwriting the oldest. Squid -k rotate is the command line usage to implement this function. Arguments number  Number of rotations Example(s) logfile_rotate 5       TAG NAME                   append_domain Description  The domain that Squid will append to requests that are not possibly fully qualified domain names (more precisely,  those that have no dots in them) Build Option  Default Usage  append_domain domainname Default  none Synopsis Using this tag, you can append the domain names to the requests that are not fully qualified domains names. Note: append_domain must begin with a period. Arguments dimainname  Domain name to be appended Example(s) append_domain .cgi.com       TAG NAME                   tcp_recv_bufsize Description  Defines the size of the buffer used for TCP packets being received Build Option  Default Usage  tcp_recv_bufsize bytes Default  tcp_recv_bufsize 0 bytes Synopsis When defined to a non-zero value, this determines the TCP packets receiving buffer size. By default Squid uses whatever the default buffer size for your operating system is. This is done by setting its value to zero. Arguments bytes  Buffer size Example(s) tcp_recv_bufsize 500 bytes       TAG NAME                   error_map Description  Map errors to custom messages Build Option  Default Usage  error_map message_url http_status... Default  none Synopsis Use in accelerators to substitute the error messages returned by servers with other custom errors. In Addition the following headers are forwarded from the client request:  User-Agent, Cookie, X-Forwarded-For, Via, Authorization,Accept, Referer And the following headers from the server reply:  Server, Via, Location, Content-Location The reply returned to the client will carry the original HTTP headers from the real error message, but with the reply body of the configured error message. Arguments message_url The received HTTP status code (i.e. 404) http_status The requested URI where the error occurred Example(s) error_map http://visolve.com/error/404.shtml 404       TAG NAME                   err_html_text Description  Provides a means to automatically add some extra information to Squid's error pages Build Option  Default Usage  err_htmal_text text Default  none Synopsis You can add HTML or plain text comments or links here, which will be added to the error messages displayed to clients. 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. Arguments text  Message to be displayed Example(s) err_html_text squid@visolve.com Consider you want to display this mail Id when access denied error occurs, then edit the corresponding file (ERR_ACCESS_DENIED in '$prefix/etc/errors' directory) with %L where this mail Id should be displayed.       TAG NAME                   deny_info Description  Used to define a customized error page for the requests which gets denied by http_access rules Build Option  Default Usage  deny_info err_page_name acl  deny_info link acl Default  none Synopsis You might have defied certain rules which filters access to certain domains. While accessing those domains, Squid normally displays a default error page. Using this tag, we can define a customized error page. Arguments err_page_name  Customized error page to be displayed acl  acl for which the page to be displayed link  Link to be displayed on deny access Example(s) acl test1 urlpath_regex -i .index.html http_access deny test1 deny_info http://www.google.co.in test1 On satisfying http_access, instead of the default error page, the site google will be loaded.       TAG NAME                   memory_pools Description  This allows Squid to keep memory that it has allocated (but no longer needs), so that it will not need to reallocate  memory in the future Build Option  Default Usage  memory_pools on|off Default  memory_pools on Synopsis Memory pools can improve performance to a small margin by allocating memory, but may need to be turned off if memory is at a premium on your system. This option defaults to on. Arguments on/off  Enable or disable memory pool feature       TAG NAME                   memory_pools_limit Description  The amount of memory Squid will keep allocated, assuming the Keep memory for future use option is turned on Build Option  Default Usage  memory_pools_limit bytes Default  none Synopsis Any non-zero value to this tag will instruct Squid not to keep more than that amount allocated, and if Squid requires more memory than that to fulfill a request, it will use your system's malloc library. Squid does not pre-allocate memory, so it is safe to set this reasonably high. If your Squid runs on a dedicated host, it is probably wisest to leave it to its default of unlimited. If it must share the system with other server processes (like Apache or Sendmail) then it might be appropriate to limit it somewhat. Arguments bytes  Memory pool limit size Example(s) memory_pools_limit 50 MB       TAG NAME                   via Description  Enable/disable via header Build Option  Default Usage  via on|off Default  via on Synopsis If set (default), Squid will include a Via header in requests and replies as required by RFC2616. Arguments on/off  Enable/disable via header       TAG NAME                   forwarded_for Description  This option allows you to choose whether Squid will report the host name of the system that originally made the  request to the origin server Build Option  Default Usage  forwarded_for on|off Default  forwarded_for on Synopsis If set, Squid will include your system's IP address or name in the HTTP requests it forwards.  By default it looks like this: X-Forwarded-For: 192.1.2.3 If you disable this, it will appear as X-Forwarded-For: unknown Arguments on/off  Enable or disable forwarding       TAG NAME                   log_icp_queries Description  Dictates whether Squid will log ICP requests Build Option  Default Usage  log_icp_queries on|off Default  log_icp_queries on Synopsis When you fell if ICP loads are very high, you can disable it otherwise you can enable for logging ICP requests. Arguments on/off  Enable or disable logging ICP queries       TAG NAME                  icp_hit_stale Description  Enable/disable to return ICP_HIT for stale cache objects Build Option  Default Usage  icp_hit_stale on|off Default  icp_hit_stale off Synopsis 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, then it is probably okay to set this to 'on'. If set to 'on', then your siblings should use the option "allow-miss" on their cache_peer lines for connecting to you. Arguments on/off  Enable or disable icp stale hit       TAG NAME                  minimum_direct_hops Description  Define minimum number of direct hops after which it directs Squid to do direct fetches Build Option  Default Usage  minimum_direct_hops number Default  minimum_direct_hops 4 Synopsis When using ICMP pinging features of Squid to determine distance to peers and origin servers, this configures when Squid should prefer going direct over a peer. This parameter plays a role in deciding latency. Arguments number  Number of hops Example(s) minimum_direct_hops 10       TAG NAME                  minimum_direct_rtt Description  Defines minimum rtt after which it directs Squid to do direct fetches Build Option  Default Usage  minimum_direct_rtt timeunits Default  minimum_direct_rtt 400            Synopsis If using the ICMP pinging stuff, do direct fetches for sites which are no more than this many rtt milliseconds away. Arguments timeunits  Round Trip Time Example(s) minimum_direct_rtt 200       TAG NAME                  cachemgr_passwd Description  Specify passwords for cachemgr operations Build Option  Default Usage  cachemgr_passwd password action action ... Default  none            Synopsis By using this we can have secured administration over the Squid. Actions: 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, 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. Arguments password  Password for the action action  Action as described above   Example(s) cachemgr_passwd secret shutdown       TAG NAME                  store_avg_object_size Description  Average object size, used to estimate number of objects your cache can hold. Build Option  Default Usage  store_avg_object_size size(Kbytes) Default  store_avg_object_size 13 KB            Synopsis To Estimate the number of objects your cache can hold: NUM_OBJ = cache_swap / store_avg_object_size where, cache_swap is the size of the cache. Arguments size  Size of the object Example(s) store_avg_object_size 100 KB       TAG NAME                  store_objects_per_bucket Description  Defines the number of objects in each store hash table Build Option  Default Usage  store_objects_per_bucket number Default  store_objects_per_bucket 20            Synopsis 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. Arguments number  Number of objects Example(s) store_objects_per_bucket 50       TAG NAME                  client_db Description  Allows you to choose whether Squid will keep statistics regarding each individual client Build Option  Default Usage  client_db on|off Default  client_db on            Synopsis If you want to disable collecting per-client statistics, then turn off client_db here. Arguments on/off  Enable or disable collecting client statistics       TAG NAME                  netdb_low, netdb_high Description  Defines low and high water marks for the ICMP measurement database Build Option  Default Usage  netdb_low number  netdb_high number Default  netdb_low 900  netdb_high 1000