HTTP proxy with caching and content filtering on a bridge
Caching proxies remember web pages and serve them up locally, saving both money and time. The most intelligent members of this family also remove dangerous content and provide transparent bridging.
When several users on the same network access the Internet multiple times for the same page, you pay a price in time and bandwidth. A caching proxy reduces traffic by storing web pages requested by users and serving them on request. A caching HTTP proxy like Squid  runs in Layer 7 of the OSI (Open Systems Interconnection) model; in other words, the Squid proxy server speaks the application protocol and can recognize the payload data. The proxy is thus capable of checking the content of a page and providing content filtering. Depending on the target direction, a proxy can either block access to undesirable pages, such as adult content on school networks, or it can keep malware out of an enterprise network.