Proxy servers use network addressing schemes to show one general (organization) IP address to the filter-out network (the internet). The proxy server acts like a funnel, which takes a lot of information from various sources, and filters it all into one specific address. Proxy servers can also be used backwards, as a way to restrict your computer from reaching certain places on the internet (certain web sites). Base proxys, meaning a lightweight, simple proxy, are often times components of computer firewall software.
Proxys have the ability to cache webpages, which means, store server requests. For example, if a computer is using a proxy to access the internet, the proxy may cache a request for a certain website in order to cut down on access time. By storing a cached copy of the request directly on the proxy, the proxy can operate faster and load web pages more efficiently for the base requesting computer.