Web Caching

Chapter 4. Configuring Cache Clients

After setting up a caching proxy on your network, you’ll need to figure out how to make your clients (browsers) use it. For many organizations, this is a particularly daunting task. There are a number of techniques you can use. Your choice is likely to depend on how many users you have, the client software they use, and whether you can configure that software. For example, a corporate information systems department usually supports one or two browsers and has full administrative control over all employee workstations. An ISP’s customers, on the other hand, maintain their own computers and run whatever software they like.

The oldest technique is what we call manual configuration. The clients are given one or more proxy addresses to use, and, with few exceptions, they forward all requests to the proxy. Manual configuration is relatively straightforward, but it’s not something most users can figure out on their own. If naive users are to manually configure their browsers, they require detailed instructions, such as those in the following section. Given the choice, some users won’t bother to configure their browser since it’s somewhat of a hassle. Another drawback is that many user-agents don’t handle failures well when manually configured.

The second-generation configuration technique, pioneered by Netscape, is known as proxy auto-configuration. Instead of a static configuration, the browser executes a JavaScript function shortly before making ...