There are a lot of proxy servers in the market. Choosing theone that’s right for your organization depends on the functionality you needfrom it. We can classify them very simply as proxies without any frills, regularproxies with some features, and high-end proxies with lots of features. Let’stake a look.

The no-frills proxy servers

The official definition of proxy is a person authorized toact for another. Remember when you called a proxy attendance for your friend inschool? Well, okay, you were not "authorized" to do it, but it wasstill a proxy. A no-frills proxy server is something similar, in that it calls aproxy for all the clients on your network. The best thing is that it doesn’tget caught, meaning nobody from the Internet can access the internal clients.Hardware Internet-sharing devices, also called Internet gateways, fall in thiscategory. Today, there are many such devices, starting from analog modem sharersto ISDN routers. These devices normally contain a DHCP server to automaticallyassign IP addresses and a gateway to all clients on your network. Gateway is theIP address of the device itself. Clients don’t need any special configurationto use these devices. These devices automatically connect to the Internet if aclient request comes in, and likewise disconnect after a user-defined period ofinactivity. Some no-frills software proxy servers are also available, which sitin the system tray of your Windows desktop, and provide the proxy function.

The regular proxy servers

Now, suppose your friends left their roll numbers with you toproxy. With a ready list, you don’t have to remember all numbers. So you won’taccidentally call a proxy for someone you’re not supposed to. A mediocre proxyserver is something similar. It gives you some additional functionality likecache memory, where it will store Web pages that have already been accessed.Some even let you modify the size of cache memory. Some proxies let you controlseveral protocols separately, such as FTP, Telnet, SOCKS, etc. There are otherswith their own DHCP server, and some let you grant or deny access to users basedon their username, IP address, etc.

The high-end proxy servers

These proxy servers have all the bells and whistles you needfor your organization. They have proxy functions for all the major protocols,and let you grant or deny access based on username, IP address, port number, andeven the application. They let you cascade multiple proxy servers if you have avery large setup. They also have advanced cache control where you can decidewhat to cache, and what to pass through straight. Some high-end proxy serverslet you control what type of downloads to allow or deny.

We’ve covered most of the popular proxy servers in allthese categories. Plus, we’ve given about 40 proxy servers on the CD with thisissue. We hope they’ll help you decide the right proxy for your organization.

Anil Chopra