Introduction to Name Servers and DNS

When any person wants to use the Internet for any purpose such as sending email or for browsing, they must use a domain name to do so. For example, the url http://www.yahoo.com is used to visit the Yahoo website. In this url, yahoo.com is the domain name that is being used to locate that particular website. However, such human-readable domain names are very easy for people to remember. But when it comes to computers and machines, they cannot recognize the domain names in this fashion. For a machine to recognize a domain name and complete your request, it needs to know the IP address (IP refers to Internet Protocol) of the website. This is where Name Servers and Domain Name System (DNS) come in.

What are Name Servers And Domain Name System (DNS)

Name Servers :

The IP address of any machine is a string of numerical numbers separated by a dot. For instance 12.10.215.30 is one example of an IP address. Whenever you send a request to a machine by using a domain name, that domain name is translated into its numerical IP address and the right site is located for you. This job of translating the domain names into numeric IP addresses is done by name servers.

So basically, a domain name server enables any Internet user anywhere in the world to reach a particular website simply by entering its domain name and not the more complex numerical IP address. Imagine having to remember hundreds of IP addresses such as 15.243.56.10, 12.14.210.47 etc instead of simple domain names such as yahoo.com, google.com etc. Thanks to name servers and DNS, you don’t have to.

Domain Name System:

Every computer that is on the Internet has its unique IP address that is different from any other. All these different IP addresses (billions of them) are managed by a single system and that is the DNS. In effect, the DNS system is a database for all these IP addresses. It is often referred to as the ‘phone book’ for the internet because that is where machines need to look so that they can find the correct IP addresses of different websites.

The DNS is a hierarchical naming system for all the resources present on the Internet. This system consists of several name servers, all of which are responsible for the domain they have been assigned to. In any domain name, there is more than one level of domain. For example:

www.yahoo.com

www.citibank.co.in

www.quest.net

In the above domain names, the last part that is COM, IN, and NET are known as the top level or first level domain. In the top level domain, there are several different second-level domain names. For instance, in the COM domain, there can be many different second-level domains such as yahoo, google, msn etc. Within one type of domain, there cannot be the same second-level domain for two different sites. But across domains, that is possible. For example, there cannot be two different sites that have the same domain name yahoo.com. However, if you change the top-level domain, then the second-level domain can be common. For example, yahoo.com and yahoo.org are both possible as the top-level domains are different.

In this manner, a domain name can have up to 127 different levels. It is the job of the DNS system to differentiate various websites by the different levels in their domain name.

As there are billions of requests to handle every single day and because different authorities would like to control their own name servers, there are many domain name servers within a DNS. Thus, the DNS system is a distributed database of different name serves, all of which work together as one integrated system.