A proxy server is a program that acts as an intermediary between computers on your LAN and computers on the Internet. Proxy servers often have a cache built in to make web surfing faster. Some proxy servers also allow the filtering of web content or domains. Additionally, almost all proxy servers support logging.

Just like other internet connection sharing technologies, only one internet connection or internet IP address is needed to serve internet data to all of the workstations on your network.

Workstations on your network must request data (like web pages) from the proxy server to access the internet. The proxy server then fetches the internet data, checks it’s filters, and returns it to the workstation that requested it. Because a proxy server does all of the data requesting, each workstation must be configured to make all internet requests from the proxy server - not the internet. Sometimes software does not allow this sort of configuration and can not be used with proxy servers.

Since proxy servers are not a ‘transparent’ connection sharing technology, configuring a proxy server for more than basic web, ftp, news and mail functionality can be challenging for a beginner.