Because proxy servers are often deployed as part of a firewall solution, this section discusses the various firewall architectures you may use at your site. The special case of reverse proxy servers and their implementation are also addressed. The proxy server can be deployed in conjunction with almost any firewall architecture. However, the firewall architecture you choose may affect the way you implement your proxy server. Three common firewall architectures are described below, but there are many variations.
All architectures use some combination of proxy servers, firewall software, and hardware routers.
A dual-homed host is a computer that has two network interfaces, one connected to an internal LAN and the other to the Internet. As a firewall architecture, the dual-homed host usually incorporates a firewall software package. This firewall basically acts as a software router providing secure connectivity through packet filtering. The proxy deployed in conjunction with a packaged firewall on a dual-homed host provides a complete firewall solution. In addition to caching, iPlanet Web Proxy Server brings fine-grain filtering and virus scanning to the solution.