Linux System Administration

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Chapter 3

CHAPTER 3

The Domain Name System

This chapter shows you how to build a Domain Name System (DNS) server using

BIND. When you finish this material you should understand how to install, config-

ure, maintain, and troubleshoot a server for any domain you register. We’ll begin

with an introduction to DNS, which you can skip if you’d rather move directly to the

step-by-step installation and configuration section. If you run into problems, you

may want to come back and read and/or review the earlier material.

DNS Basics

If you do any research on the Internet’s DNS, you are certain to encounter the claim

that DNS is the world’s largest database. Comparing it to a database like Oracle or

MySQL is misleading, though. In fact, DNS is the world’s largest distributed digital

directory. Like an online telephone directory, you use it to match names with num-

bers—but with DNS, the numbers are the IP addresses of the multitude of servers

connected to the Internet, including those that manage small web sites and gigantic

server farms like Google and Amazon.

Like the public library with its master collection of phone books separated by states,

DNS separates domains into categories. The master collection of categories lives in

what we call root directories. This collection is divided into top-level domains

(TLDs), in much the same way that the master collection of phone books is divided

into states. Instead ...