Ubuntu Unleashed 2011 Edition: Covering 10.10 and 11.04 (6th Edition)

A proxy server lies between client machinesthe desktops in your companyand the Internet. As clients request websites, they do not connect directly to the Web and send the HTTP request. Instead, they connect to the local proxy server. The proxy then forwards their request on to the Web, retrieves the result, and hands it back to the client. At its simplest, a proxy server really is just an extra layer between client and server, so why bother?

The three main reasons for deploying a proxy server are as follows:

• Content control You want to stop people whiling away their work hours reading the news or downloading MP3s.

• Speed You want to cache common sites to make the most of your bandwidth.

• Security You want to monitor what people are doing.

Squid is capable of all of these and more.