A Proxy Server is a computer system or application program which services the requests of clients by forwarding it to other servers. The service requested may be a web page, file, connection, or other resource, available from a different server. The proxy server may modify the client’s request or the server response depending on the configuration.
There are different types of proxy servers available
1. Caching proxies: Web pages which are frequently requested by clients are often cached on the proxy server. This makes the proxy server more efficient, as lesser bandwidth is needed by the server from upsteam bandwidth provider. However, this may be inconvenient for the end user as it may also cause delays in accessing the latest version of a particular website.
2. Web proxy are proxies which service requests related to web traffic. Some proxy programs like Squid, Netcache can block access to certain URLs which are blacklisted and this is used for content filtering. Most commercial and non commercial organisations (like schools, colleges and government organizations which provide free access to users) use web proxies to ensure that internet usage conforms to the acceptable usage policy.
For access using a content filter proxy, the user must authenticate his or her identity. Reports regarding the URLs accessed and bandwidth used by a particular user can also be generated.