Large business and most ISPs have a caching proxy and these machines are built to deliver the file system performance and contain the hot-rodded versions to TCP. Poorly-implemented caching has use downsides, and some problems are described in the RFC 3143.

Content-filtering web proxy

Content filtering proxy servers provide administrative control over content that may be relayed through proxy. Commonly, it is used in both non-commercial and commercial organization to ensure that usage of Internet conforms to acceptable the policy use.

User can circumvent proxy in some cases, since there are services designed to proxy information from filtered website through non filtered site to allow it through user proxy. Common methods are used for content filtering include DNS blacklists or URL regex filtering.

Anonymizing proxy server

This proxy server generally attempts to anonymize the web surfing and there are varieties of anonymizers. One of its more common variations is open proxy, due to typically difficult track, where open proxies are useful especially to that anonymity seeking online from the political dissidents to computer criminals.

Some of the users are interested merely in anonymity on the principle to facilitate the constitutional rights of freedom of speech for the instance. Server receives request from anonymizing proxy server and does not anonymous to anonymizing proxy server so a degree of trust continued between user and server. Some anonymizing may forward packets of data with header lines such as HTTP_X_FORWARDED which may reveal IP address of client. Websites could suspect proxy being used if client sends packets use high anonymity proxy servers, Cookies clearing would possibly solve this problem.