Web Caching

Caching Proxy Features

The key feature of a caching proxy is its ability to store responses for later use. This is what saves you time and bandwidth. Caching proxies actually tend to have a wide range of additional features that many organizations find valuable. Most of these are things you can do only with a proxy but which have relatively little to do with caching. For example, if you want to authenticate your users, but don’t care about caching, you might use a caching proxy product anyway. I’ll introduce some of the features here, with detailed discussions to follow in later chapters of this book.

Authentication

A proxy can require users to authenticate themselves before it serves any requests. This is particularly useful for firewall proxies. When each user has a unique username and password, only authorized individuals can surf the Web from inside your network. Furthermore, it provides a higher quality audit trail in the event of problems.

Request filtering

Caching proxies are often used to filter requests from users. Corporations usually have policies that prohibit employees from viewing pornography at work. To help enforce the policy, the corporate proxy can be configured to deny requests to known pornographic sites. Request filtering is somewhat controversial. Some people equate it with censorship and correctly point out that filtering schemes are not perfect.

Response filtering

In addition to filtering requests, proxies can also filter responses. This usually involves checking ...