|Domain Name Servers (DNS) track
the name and address of every computer on the Internet. Here how DNS works:Imagine,
for a moment, that we had to address one another by our Social Security
numbers. It would work for maybe the first ten people we got to know,
but beyond that we'd likely never remember what to call anyone. Human
beings, for many reasons, remember names better than numbers.
Switch to the Internet. You want to launch a telnet session, and you know the address of the telnet site at the National Center for Supercomputing Applications is ncsa.uiuc.edu. Then you decide to access the Microsoft Web site, and you guess that the address is probably www.microsoft.com, so you try it. It works, and you commit both addresses to memory.
What you've done, however, is simply memorize the domain names of the computers you're connecting with. From the Internet's standpoint, you haven't actually identified anything. Computers on the Internet are identified by numbers, not by names, and the domain name is merely a human-friendly pseudonym for the computer's real ID. On the Internet, each computer is assigned an Internet Protocol (IP) address, and this numeric identifier differentiates one computer from another. You may prefer to know them by name, but the Internet prefers the vital statistics.