Proxy

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[edit] What is a Proxy?

A proxy server is a web server that can be found between, for example, a client PC web browser and the actual web server. When the client application sends a request to the actual server, the proxy server intercepts the request and tries to comply with it. If the proxy server cannot complete the request it is then forwarded to the real server.

As proxy servers fulfill requests, the results are stored in its cache, So, the next time a client sends the same requests, the result is taken from the proxy’s cache, dramatically reducing response time. Proxy servers can thus be used for servers that, for example, have very high traffic to reduce response time to each request. The real server can then respond to all requests that the proxies cannot fulfill, improving performance drastically.

Another application for proxy servers is to filter requests. This way, companies can limit the sites that their employees can access online and the server can also provide additional security. Lastly, online or web-based proxies are also used for anonymous surfing, hiding the user’s IP to prevent sites from retrieving personal information from web users.

[edit] What is a Web Proxy / Proxy Server?

Proxies that focus on WWW traffic are called web proxies. Many web proxies attempt to block offensive web content. Other web proxies reformat web pages for a specific purpose or audience (e.g., cell phones and PDAs for persons with disabilities).

Many organizations — including schools, corporations, and countries — use proxy servers to enforce acceptable network use policies (see content-control software) or to provide security, anti-malware, and caching services. A traditional web proxy is not transparent to the client application, which must be configured to use the proxy (manually or with a configuration script). In some cases, where alternative means of connection to the Internet are available (e.g., a SOCKS server or NAT connection), the user might be able to avoid policy control by simply resetting the client configuration and bypassing the proxy. Furthermore, administration of browser configuration can be a burden for network administrators.

Access control: Some proxy servers implement a logon requirement. In large organizations, authorized users must log on to gain access to the WWW. The organization can thereby track usage to individuals.

Web Proxies such as ProxySurfing and ProxyTrail became well known when Google in the UK required all Gmail users to have a @googlemail.com email address rather than the standard @gmail.com address. The web proxies were used to bypass restrictions put on and allowed UK users to have the @gmail address.