LPI Linux Certification in a Nutshell, 2nd Edition

Squid as Web Accelerator

In addition to the proxying aspects of Squid, it can also be used as a web accelerator. This is very similar in concept to Squid as a proxy server, but in this case, Squid is "closer" to the web server that is being queried. Squid sits "in front" of the web server, and when a request is made from any web browser for content that is on the web server, that request is handled by Squid. If Squid has the requested content in the cache, it is served directly to the client. If the content is not in the cache, Squid gets the content from the web server and then serves it to the client. This is useful in a number of situations:

If the original web server is too slow to handle all the requests

Because this setup puts less load on the web server itself (and more on Squid), performance increases.

If the original web server is on a slow line, which can't handle all of the traffic

If the Squid system is on a faster line, requests can come into Squid, and Squid will query the web server over the slow line only when a request cannot be fulfilled from the cache.

Let's look at an example configuration that would allow a Squid system to sit "in front" of a web server and handle incoming requests for it. Assume the Squid system has two network cards, one connected to a DSL router with an IP address of 1.1.1.1/255.255.255.0 and one connected to a switch with an IP address of 192.168.1.1/255.255.255.0. The web server we want to handle requests for is connected to the same ...