Open SUSE® 11.0 and SUSE® Linux® Enterprise Server Bible

Chapter 26. Setting Up a Web Proxy with Squid

IN THIS CHAPTER

• Getting started with Squid on SUSE

• Authentication and ACLs

• The Squid log and using sarg

• Transparent proxying

• Using Cache Manager and squidGuard

Squid is the most popular open source caching web proxy server. This means that it fetches and holds local copies of pages and images from the web. Client machines requesting these objects obtain them from the Squid proxy server rather than directly. There are several good reasons (and possibly some bad ones) why people use Squid and other caching web proxies:

• A web cache on the local network means that objects (web pages, images, and so on) that have already been requested do not need to be fetched again from their original location, but can be served from the cache instead. This improves performance for users and reduces bandwidth usage.

• At the same time, using a proxy can give an organization a great deal of control over how and when users access the web and can log all web access. Squid can also be used to prevent access to undesirable sites, sometimes in conjunction with additional software that maintains blacklists of these sites.

• The use of a web proxy such as Squid that can fetch and cache web and FTP accesses means that you can set up a firewall in such a way that users do not have direct access from their PCs to the Internet; their HTTP and FTP traffic is handled by Squid, and their Simple Mail Transport Protocol (SMTP) traffic is handled by the mail server. Typically, users ...