Editing Squid (software) (section)

==Basic functionality==
After a Squid proxy server is installed, [[web browser]]s can be configured to use it as a [[Proxy server|proxy]] HTTP server, allowing Squid to retain copies of the documents returned, which, on repeated requests for the same documents, can reduce access time as well as [[Bandwidth (computing)|bandwidth]] consumption. This is often useful for [[Internet service provider]]s to increase speed to their customers, and [[local area network|LANs]] that share an [[Internet]] connection. Because the caching servers are controlled by the web service operator, caching proxies do not anonymize the user and should not be confused with anonymizing proxies.

A client program (e.g. browser) either has to specify explicitly the proxy server it wants to use (typical for ISP customers), or it could be using a proxy without any extra configuration: "transparent caching", in which case all outgoing HTTP requests are intercepted by Squid and all responses are cached. The latter is typically a corporate set-up (all clients are on the same LAN) and often introduces the privacy concerns mentioned above.

Squid has some features that can help [[Anonymity|anonymize]] connections, such as disabling or changing specific header fields in a [[client (computing)|client's]] HTTP requests. Whether these are set, and what they are set to do, is up to the person who controls the computer running Squid. People requesting pages through a network which transparently uses Squid may not know whether this information is being logged.<ref>See the documentation for {{mono|header_access}} and {{mono|header_replace}} for further details.</ref> Within UK organisations at least, users should be informed if computers or internet connections are being monitored.<ref>See, for example, [http://www.yourprivacy.co.uk/computer-monitoring-workplace-your-privacy.html Computer Monitoring In The Workplace and Your Privacy]</ref>