proxy

quote:
Someone with a Web browser on their computer can use it to get a Web page directly from a Web server. The Web server is usually attached to the Internet and could be any where in the world.

Alternatively, the Web browser can let an intermediate computer get the Web page from the Web server. The intermediate computer therefore acts as proxy. The proxy computer will get the information and pass it to the browser so that the user can display it.

The proxy computer can also store a local copy of the information for itself. This is known as caching. The proxy computer can then supply the same information (to the next user who wants it) from its local cache, instead of getting it from the Internet.

If the required Web page is already stored in the cache on the proxy computer, then the user should receive the information faster than going direct to the original Web server on the Internet. This also reduces the amount of Internet traffic generated and any associated costs.

quote:A proxy server is used to give access to network services indirectly. All accesses are handled through the proxy server. There are two main reasons for using proxy servers; to enhance security and to reduce network bandwidth.
The rationale for enhancing security through use of a proxy server is that only the computer running the proxy server will access the Internet directly. Therefore it is only that machine that is vulnerable to attacks from the Internet. And since securing one machine is much simpler than securing all machines, security is enhanced.

Network bandwidth can be reduced by the proxy caching requests. If several users request the same page it will only need to be fetched once over the network. Unfortunatly not many pages are cachable, since there are so much dynamic pages out there. But it is usually possible to cache images.