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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 ...