If you've used a computer connected to the internet for any period of time, chances are you've used an internet proxy server. These are special servers that exist to forward your requests to other servers. They can also help speed up response times by caching popular requests so that they don't have to access the other server every time. But what exactly is an internet proxy, and what can you use one for?

An internet proxy server is kind of like a secretary in a big office firm. When someone comes into the firm, the secretary takes their request and contacts the appropriate person for the information needed. A proxy does the same thing. When you send a request over the internet (i.e., when you search for something on a search engine, click on a webpage link, download a file, or do just about anything online, really), the proxy server gets your request and passes it on to the appropriate server.

Of course, a proxy server can do much more. It can actually modify your request or the information the server sends back. But don't worry too much about that, the proxy isn't going to change your Google query or anything like that! The biggest change a proxy server makes is to add your credentials to the information you sent so you can access specific information. Proxies can also be used to increase response time and block information.

One of the biggest uses for proxies is to speed up response time by caching. These caching proxy servers, as they are called, save the information sent to previous users for a set amount of time. During this time, if another user requests the same information, the proxy sends the saved information instead of taking the time to contact the other server and downloading the information again. This speeds up response time and reduces the amount of internet bandwidth used, which can actually save money.

Of course, there are some factors to consider with using a caching proxy server. One is the amount of hard drive space on the server: you'll need a good amount of space to save the cached information. For that reason, often only the most requested information is cached. Another factor is changing information. If the information on the remote server is updated, the caching proxy might still send out the information it had saved, which would not include the updates. For that reason, the programming for a caching proxy server is pretty complex and involves many rules for what information to save and for when the server should check for updated information.

Another major use of internet proxy servers is to check requests and, if necessary, deny them. This has two uses: the first is in regards to security. The proxy can check and see if a user should have access to the information he or she has asked for. If they shouldn't, the proxy will deny them the information (usually by asking for a login ID or password). Large companies often use proxies to protect sensitive information that only specific employees should have access to.

The other use of proxy servers is to deny users access to specific websites. Many schools and businesses are using this function of proxy servers to block pornographic sites or sites like Yahoo games or MySpace. Businesses usually don't want employees wasting their time on sites like this, while schools want to keep students away from any site that is potentially harmful or R-rated. Of course, computer hackers often find ways to get around proxy servers.

These uses are just the basic ways an internet proxy server can be used. In the hands of a network administrator, proxy servers can be used in a variety of ways, information control, user access, data compression, and more.