The proxy technology, which has developed greatly in the last years, offers the perfect solution for organizations sitting on a closed subnet behind a firewall, who are interested in giving their employees a controlled access to the Internet. A proxy is in fact, an http server that sits on a firewall machine and usually has a caching ability making surfing much faster.
This ability makes it attractive also in case there is no firewall. It also allows one to read documents "unplugged" to the Internet. This caching proxy functions as a server when connected by a client, and as a client when contacting the original server.
Today's proxies are very sophisticated, so that the security "holes" are minimal.
Has firewall functionality, and caching ability as well.
Caches Web pages and scans for viruses at the same time.