The D-N-What: A Layman’s Guide to the Domain Naming System

The Domain Naming System used on the Internet is a very complex. For most users, if the server that controls the names for Web sites, such as yahoo.com, goes down, the Internet connection is useless because 99.99% of Internet work is driven by domain names, and not IP addresses. The Domain Naming System (DNS) is so complicated that only very few system administrators know it well. However, an understanding of the DNS is becoming more and more of a requirement for system admin jobs as the use of computer networks rises.

The Domain Naming System used on the Internet is a very complex. For most users, if the server that controls the names for Web sites, such as yahoo.com, goes down, the Internet connection is useless because 99.99% of Internet work is driven by domain names, and not IP addresses.

If you don’t know anything about DNS now, it’s time to learn.

When someone wants to visit the PC Mechanic Web site, for example, he or she will type “http://www.pcmech.com” into the Internet browser because that’s how it’s set up, no questions asked. But it’s set up that way for humans. PC Mechanic’s IP address, which computers use to communicate with each other, is 209.68.45.231. It is a DNS translating between the two. Because of DNS, www.pcmech.com=209.68.45.231, similar to programming variables. www.pcmech.com can be used in place of 209.68.45.231, instead of typing in that number every time. This is obviously much easier for people to remember, and therefore increases the chances of visitors coming back to the site.

DNS isn’t quite that simple. However, from a basic standpoint, DNS is just a shared database of domain names and their appropriate IP address. Name servers, more commonly and ironically called DNS servers, hold these databases. Most of the time, they are Unix-type machines running a version of Berkley Internet Naming Software (BIND). In this tutorial we will try to explain how these servers work.