Overview of DNS
For the communication to takes place, the information should pass through seven layers. Application layer is one among the seven layers. There are several applications in the application layer and DNS (Domain Name System) is one among them. Internet is based on IP addresses, not domain names. But it is easy to use domain names to refer them rather than the long numbers (IP address). To enable the use of domain names in a network, the Domain Name System (DNS) is used. Domain names to IP address mapping must be consistent across the network to ensure interoperability. DNS provides the domain name to IP address mapping through Name servers. To know more about DNS working we must first know about IP address, URL and DNS components. So, let us see about each in detail. Refer Figure 12.1
While typing a web address, e.g., www.tnschools.gov.in, DNS translates it into a machine friendly IP address (for example 184.108.40.206 is the IP for www.tnschools.in) and directs your Internet connection to the correct website.
American computer scientist Paul V. Mockapetris together with Jon Postel, invented the Internet Domain Name System (DNS) Jon Postel was an administrator of the Internet Assigned Numbers Authority (IANA) until his death and he was known as “God of the Internet”.