Proxy server acts as an intermediary between your internal network (intranet) and the internet, retrieving files from remote web servers. In UTAR environment, the proxy server setting is used based on three main functions:

l        Fire walling & Filtering

l        Connection sharing

l        Caching

Fire walling & Filtering

Referring to model OSI 7 layers, proxy server works at application layer. The proxy server has the capability that ordinary firewall simply can’t be provided. However, proxy functionality for each application protocol must be configured individually, hence, the proxy server is also difficult to be installed and maintained. But, once the configuration is correctly be set, the network security that is given will be more reliability if comparing with the ordinary firewall.

By using filtering, URL of outgoing requests for Web pages by inspecting HTTP GET and POST messages can be checked by the proxy web servers. Using this feature, some illegal domain can be stopped and in the other way, others site is allowed to access. Besides that, the proxy server can also filter the file based on the content inside the message.

Connection sharing

In fact the proxy serve offer a more scalable and cost-effective alternative for shared Internet access since recently a lot of software product for connection sharing on small home network have appeared. All the internal connection can be funneled through one or more proxies that in turn connect to the outside rather than give each client computer a direct Internet connection,

Caching

They are 3 ways to improve the network’s “quality of services” through using the caching.

l        Firstly, bandwidth maybe saved by caching on the network, for increasing scalability.

l        Secondly, response time experienced by clients can be improved with using caching. With an HTTP prove cache, the user can access the web site faster through web browser.

l        Finally, when the original source or an intermediate network link goes offline, the user still able to access the web pages or other files in the cache remain.