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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 TIMEOUT Timeout parameters in Squid can be based on overall connection timeouts, peer-specific timeouts, site/domain-specific timeouts, request-specific timeouts etc. Proper setting of timeout values is critical to optimal Squid performance. Relevant parameters for timeout settings are listed here. forward_timeout connect_timeout peer_connect_timeout read_timeout request_timeout persistent_request_timeout client_lifetime half_closed_clients pconn_timeout ident_timeout shutdown_lifetime

TAG NAME                   forward_timeout Description  Specifies how long Squid should at most attempt in finding a forwarding path for the request before giving up. Build Option  Default Usage  forward_timeout time-units Default  forward_timeout 4 minutes Synopsis This parameter specifies how long Squid should at most attempt in finding a forwarding path for the request before giving up. Arguments time-units  Connection timeout period Example(s) forward_timeout 4 minutes       TAG NAME                   connect_timeout Description  An option to force Squid to close connections after a specified time Build Option  Default Usage  connect_timeout time-units Default  connect_timeout 2 minutes Synopsis Some systems (notably older Linux versions) can not be relied upon to time out connect requests. For this reason, this option specifies the timeout for how long Squid should wait for the connection to complete. This value defaults to 120 seconds (2 minutes). Arguments time-units  Connection timeout period Example(s) connect_timeout 180 seconds       TAG NAME                   peer_connect_timeout Description  This parameter specifies how long to wait for a pending TCP connection to a peer cache Build Option  Default Usage  peer_connect_timeout time-units Default  peer_connect_timeout 30 seconds Synopsis default is 30 seconds. You may also set different timeout values for individual neighbors with the 'connect-timeout' option on a cache_peer line. Note: Setting of peer_connect_timeout to more than 30 seconds will be a performance issue. Arguments time-units  Time to wait for pending TCP connection Example(s) peer_connect_timeout 45 seconds       TAG NAME                   read_timeout Description  Used to set the timeout period for server-side connections Build Option  Default Usage  read_timeout time-units Default  read_timeout 15 minutes Synopsis On each successful read() request the timeout is reset to this amount. If no data is read within this period of time, the request is aborted and logged with ERR_READ_TIMEOUT. Arguments time-units  Reset time duration Example(s) read_timeout 10 minutes       TAG NAME                   request_timeout Description  Defines the timeout for HTTP requests from clients Build Option  Default Usage  request_timeout time-units Default  request_timeout 5 minutes Synopsis Using this, instruct Squid to wait for an HTTP request after initial connection establishment. By default the value is 5 minutes. Arguments time-units  Wait time period after initial connection establishment Example(s) request_timeout 8 minutes       TAG NAME                   persistent_request_timeout Description  This defines the time period to wait for the next HTTP request on a persistent connection after the previous request  completes Build Option  Default Usage  persistent_request_timeout time-units Default  persistent_request_timeout 1 minute Synopsis This tag defines the time period between completion of a HTTP request and starting of the next request on persistent connection. Arguments time-units  Time duration between the requests Example(s) persistent_request_timeout 1 minute       TAG NAME                   client_lifetime Description  The time limit Squid sets for a client to remain connected to the cache process Build Option  Default Usage  client_lifetime time-units Default  client_lifetime 1 day Synopsis This defines the maximum amount of time that a client (browser) is allowed to remain connected to the cache process. This is merely a safeguard against clients that disappear without properly shutting down. It is designed to prevent a large number of sockets from being tied up in a CLOSE_WAIT state. The default for this option is 1440 minutes, or 1 day. 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 file descriptors, we recommend first tuning the read_timeout, request_timeout, pconn_timeout and quick_abort values. If the more file descriptors are in use then the memory in use will also increase, which is also a performance issue. Arguments time-units  Client lifetime with the cache Example(s) client_lifetime 1000 minutes       TAG NAME                   half_closed_clients Description  Defines Squid's behavior towards some types of clients that close the sending side of a connection while leaving the  receiving side open Build Option  Default Usage  half_closed_clients on/off Default  half_closed_clients on Synopsis Turning this option off will cause Squid to immediately close connections when a read(2) returns "no more data to read". It's usually safe to leave this at the default value of on. Arguments on/off  Enable or disable this action Example(s) half_closed_clients off       TAG NAME                   pconn_timeout Description  Defines the timeout value for persistent connections Build Option  Default Usage  pconn_timeout time-units Default  pconn_timeout 120 seconds Synopsis When this timeout is set, Squid will close persistent connections if they are idle for this amount of time. Persistent connections will be disabled entirely if this option is set to a value less than 10 seconds. The default is 120 seconds. Arguments time-units  Time period to wait for closing idle connections Example(s) pconn_timeout 2 minutes       TAG NAME                   ident_timeout Description  Maximum time to wait for IDENT lookups to complete Build Option  Default Usage  ident_timeout time-units Default  ident_timeout 10 seconds Synopsis The timeout, usually in seconds. If this is set too high, you may be susceptible to denial or service from having too many outstanding ident requests. The default for this is 10 seconds. Arguments time-units  Time duration to wait during ident lookups Example(s) ident_timeout 5 seconds       TAG NAME                   shutdown_lifetime Description  This is the time Squid allows for existing connections to continue after it has received a shutdown signal Build Option  Default Usage  shutdown_lifetime time-units Default  shutdown_lifetime 30 seconds Synopsis When SIGTERM or SIGHUP is received, the cache is put into "shutdown pending" mode until all active sockets are closed. It will stop accepting new connections immediately, but connections already in progress will continue to be served for this amount of time. Defaults to 30 seconds, which is a good safe value. Any active clients after this many seconds will receive a "timeout" message. Note If this time is set to be too low then some file descriptors may remain open which will be a performance issue in memory usage. Arguments time-units  Time period of "shutdown pending" mode Example(s) shutdown_lifetime 20 seconds