Transparent HTTP Proxies

As mentioned earlier, a forward caching proxy requires that each client be properly configured. It is also possible to implement so-called transparent proxies. These machines intercept HTTP requests at the network layer and "transparently" serve them through a proxy server without the end-user noticing it. Transparent proxies are still popular with ISPs that want to cut down on bandwidth costs or control the surfing habits of their customers. Some organizations also use transparent proxies to filter spyware and viruses, as mentioned earlier in the "Enabling Forward Proxy Support" section. A typical transparent proxy setup involves using a transparent-proxyingaware server, such as Squid, and modifying your operating system's packet forwarding rules. You can learn more about setting up transparent HTTP proxies at the following Linux Documentation Project how to:

http://www.tldp.org/HOWTO/TransparentProxy.html