A proxy server is a computer that offers a computer network service to allow clients to make indirect network connections to other network services. A client connects to the proxy server, then requests a connection, file, or other resource available on a different server. The proxy provides the resource either by connecting to the specified server or by serving it from a cache. In some cases, the proxy may alter the client's request or the server's response for various purposes.
Proxy transparencyMany organizations — including corporations, schools, and families — use proxy servers to enforce network use policies (see censorware) or provide security and caching services. Usually, the web proxy is not transparent to the client application: it must be configured to use the proxy, manually or with a configuration script. Thus, the user can evade the proxy by simply resetting the client configuration, except in the case where the proxy is used instead of a NAT router to share an internet connection or a LAN. Such proxies may be difficult to configure for applications requiring a large port range out going and may only be able to route inward to a single server for a given UDP or TCP port (see Wingate 2.x versions). However such proxies may have more extensive logging or more customizable security than a simple NAT router box.
A transparent proxy or transproxy (also known as a forced proxy) combines a proxy server with NAT so that connections are routed into the proxy without client-side configuration. However, RFC 3040 defines this type as intercepting proxy

نوشته شده در سه شنبه دوم خرداد 1385ساعت 0:38  توسط بامداد هیدن |-|
|