CMS Security Handbook: The Comprehensive Guide for WordPress®, Joomla!®, Drupal™, and Plone®

Domain Name System Servers

The domain name system (DNS) is essentially the Internet's telephone book. DNS is the map that browsers follow to reach websites and other computers on the Internet. Normally, you don't have much worry about with DNS after it's set up and running. The biggest concern you should have about DNS is maintaining the software on the machine and protecting it from attack.

DNS is probably one of the most critical pieces of technology on the Internet. Without it, there simply would not be an Internet, only a collection of machines with little capability to communicate.

This section dives into the shallow end of the DNS pool to help you learn about how it works, and how to protect it.

Understanding DNS

Today's Internet is vastly different, more complex, and more populated than the original implementation known as ARPANET (Advanced Research Projects Agency Network).

Back in the day, computers would be connected point to point — in other words, they were connected directly to one another. ARPANET enabled the computers (early servers) to use a network to reach any of the other computers on the network. The scientists working on the system maintained a list called the host list. To connect, the systems would look at that list, and then discover the route. As the early Internet (formerly the ARPANET) grew, that list quickly became too large to manage. Out of that was born DNS.

DNS is a distributed database of hosting information. In simple terms, it's a giant version ...