pete @ linux1.ca
Date: April 2012
When we access the Internet we typically do so by accessing systems using a somewhat meaningful hostname often in the form of a web based URL. Network and computer equipment reference a system by it's IP Address, and in some cases by the machines Physical Address which is not covered in this article. This DNS primer is intended to shed some light on the workings behind resolving a domain name to an IP Address.
Domain Name System (DNS) is the system that matches host names to IP addresses and sometimes the reverse. DNS allows a client program, called a resolver, to locate the IP address of any device that is defined on a DNS server anywhere on the Internet or any other accessible DNS managed network. Understanding the fundamentals of how DNS works is essential for any administrator in troubleshooting network issues, and in the case of a user just understanding why things fail can relieve some of the stress.
Like a good Systems Administrator, when everything is working as expected, DNS is rarely on anyone's mind. It's a different story when DNS fails and you can't access any of your favourite sites. Even accessing by IP Address these days can fail because many web servers host a number of different web sites based on the host name within the request.
Berkeley Internet Name Domain (BIND) is the dominant name server used on the Internet and other networks.