Web Caching

A web proxy server is a server on the local network that keeps copies of recently retrieved or often used web pages, or parts of pages. When the next person retrieves these pages, they are served from the local proxy server instead of from the Internet. This results in significantly faster web access in most cases, while reducing overall Internet bandwidth usage. When a proxy server is implemented, the administrator should also be aware that some pages are not cacheable--for example, pages that are the output of server-side scripts, or other dynamically generated content.

The apparent loading of web pages is also affected. With a slow Internet link, a typical page begins to load slowly, first showing some text and then displaying the graphics one by one. In a network with a proxy server, there could be a delay when nothing seems to happen, and then the page will load almost at once. This happens because the information is sent to the computer so quickly that it spends a perceptible amount of time rendering the page. The overall time it takes to load the whole page might take only ten seconds (whereas without a proxy server, it may take 30 seconds to load the page gradually). But unless this is explained to some impatient users, they may say the proxy server has made things slower. It is usually the task of the network administrator to deal with user perception issues like these.