Domain Name System and Name Servers
While it is possible for Internet clients to access a server by using its IP address, it becomes a burden remembering a string of numbers for each of your favorite sites. Plus, some IP address are not permanent so the address is not always known.
This invites the usefulness of the Domain Name System (DNS), which broadcasts more "friendly" names that correspond to IP addresses on the Internet. With DNS, a user can type in a domain name--such as mydomain.com, which is translated to its numerical address--such as 22.214.171.124. As an example, in most Web browsers you can see the domain name being resolved. This is displayed at the bottom of most browser windows. When you type in a web address the status bar of your browser may display:
Connecting to site 126.96.36.199...
Web site found, waiting for reply...
This indicates that your machine was able to match the IP address to the entered domain name. In order to do this, a computer needs a reference in which to look up domain names and match them to their corresponding IP addresses, much like how you would use a telephone book to correspond a friend's name to their number. DNS, commonly referred to as your Name Server, is the computer's phone book for the Internet.
When initially setting up a computer to the Internet, you are required to give it at least one name server so the computer knows where to look up the IP addresses of the domain names you access. Most people use two name servers: primary and secondary. This provides a redundant system so that in case one fails there is a backup. Most users of the Internet, without knowing it, rely on DNS.
A name server's only function is to maintain a table of domain names and matching IP addresses, called a DNS Table. Each domain name on the Internet has specific DNS servers that are responsible for keeping their information in their table and that DNS server is then responsible for broadcasting that information across the Internet.
Most likely, you chose a domain or a subdomain name for your account when you first signed up. Even if you didn't choose one, often we can assign you a temporary one in front of our domain name. In either case, your domain already has an entry in the DNS tables of our name servers. This entry is an important part of what makes it possible for people to access your site on the Internet.