Network Security Bible, 2nd Edition

Chapter 13. Domain Name System

IN THIS CHAPTER

• Understanding the role of DNS

• Identifying common DNS security weaknesses and attacks

• Explaining single-server, split, and split-split DNS designs

• Building a DNS architecture

• Implementing DNS

• Knowing how DNS SEC can be used

When the Internet first began and was known as ARPANET, it was a small community of universally known IP addresses. As it grew to the bustling size of a few hundred hosts, memorizing and identifying servers by numbers was difficult and inefficient. Because numbers are more difficult for humans to remember, names were developed for servers. So instead of 15.5.5.5 you could say http://wiley.com. However, there needed to be a way to link the IP address to a domain name.

To diminish this burden, a flat text file, hosts.txt, was created, which contained a listing of server IP addresses and descriptive hostnames. The following is a sample of what this would look like:

15.5.5.1     Eric

15.5.5.2     Server

Now if someone wanted to use SSH to connect to the system, they could type either SSH 15.5.5.1 or SSH Eric and it would work.

This file was maintained on a single server by the Network Information Center (NIC) of Stanford Research Institute (SRI). Each administrator was responsible for maintaining an up-to-date copy from the central server on their own host.

This system posed many limitations, including restrictions on domain name selection, inaccuracy, and inefficiency for participating administrators.

As a result, in 1984 Paul Mockapetris ...