Adapted from the homepage:
A caching engine usually installed on a remote server. Caching is a way to store requested Internet objects (i.e., data available via the HTTP, FTP, and gopher protocols) on a system closer to the requesting site. Web browsers can then use the local Squid cache as a proxy HTTP server, reducing access time as well as bandwidth consumption. This is often useful for ISPs to increase speed to their customers, also known as Web Server Acceleration, and LANs that share an Internet connection. Because it is also a proxy, it provides some anonymity and security.
It has some nice features that can further help anonymize your connections, such as disabling or changing specific header fields in a client's HTTP requests. See the documentation for <code>header_access</code> and <code>header_replace</code> for further details.
Another feature is something called "tranparant caching," a way to avoid configuring the client browser, with HTTP requests intercepted by squid. Some support is available for TLS, SSL, and HTTPS. Current stable version is 2.5.
Squid is able to run on the following operating systems:
- Mac OS X
- OSF and Digital Unix
- SCO Unix
- Squidguard - A flexible plugin for advanced filtering.
- ufdbGuard - commercial URL filter for Squid that claims to be the fastest.
- Squid + PF - Transparent proxying with Squid and PF.
- DansGuardian - Smart filtering, can be used together with Squid.
- Setting up Squid on FreeBsd - Setting up Squid as caching proxy server.
- OpenSourceHowTo.Org - Squid - Setting up Squid with PAM authentication , NTLM authentication, ClamAV & HAVP, Squid1-ntlm - DansGuardian - Squid2-cache, Personalized Denial page for squid & Squish download manager