Proxy servers

A proxy server is an appliance or application that acts as an intermediary for communicating between computers. A computer has a request for information. The packets are sent to the designated resource but before they can get there they are blocked by the proxy server saying that it will take the request and pass it on. The Proxy Server processes the request and if it is valid it passes onto the designated computer. The designated computer gets the packet and processes the request, sending the answer back to the proxy server. The proxy server sends the information back to the originating computer. It’s all a little like a situation with two people who refuse to talk directly with each other using someone else to take messages back and forth.

From a security stand point a Proxy Server can serve a few purposes:

• Protects the anonymity of the originating computer l The two computers never deal directly with each other l Packets that are not configured to be forwarded are dropped before reaching the destination computer. l If malicious code is sent it will affect the Proxy server with out affecting the originating or sending computer.

Proxies can perform a number of roles including:

• Content Filtering l Caching l DNS proxy
• Bypassing Filters and Censorship l Logging and eavesdropping l Gateways to private networks l Accessing service anonymously