Domain Name System in Computer Network
Domain Name System
Domain Name System is also called DNS. DNS was introduced by Paul Mockapetris and Jon Postel in 1983. DNS is an internet service that converts Domain names to IP addresses. When the user types any domain name in a web browser, then the DNS server converts that domain name to IP address.
For example - When a user types www.javatpoint.com in a web browser, DNS changes it to an IP address 198.15.45.18. Now you see for yourself how easy it is to remember www.javatpoint.com, while how difficult it is to remember the IP address 198.15.45.18.
If one DNS server does not convert the domain name, it asks the other DNS server to convert the domain name, and the process continues until the domain name will be converted.
DNS in the Internet
On the internet, DNS is a protocol. It is used on various platforms. The tree of the domain name system is divided into three categories: generic domains, country domains, and the inverse domains.
Generic Domains
It defines the registered hosts by their common actions. Every node of the tree represents a domain. It is an index of the DNS database that is shown in the figure below.
It gives the 14 possible labels. The description of these labels is shown in the table.
| Label | Description |
| aero | Airlines and aerospace companies |
| biz | Businesses or firms (similar to “com”) |
| com | Commercial organizations |
| coop | Cooperative business organizations |
| edu | Educational institutions |
| gov | Government institutions |
| info | Information service providers |
| int | International organizations |
| mil | Military groups |
| museum | Museums and other nonprofit organizations |
| name | Personal names (individuals) |
| net | Network support centers |
| org | Nonprofit organizations |
| pro | Professional individual organizations |
Country Domains
The country domain uses only two characters for the country abbreviations, such as (in = India). In the country domain, second labels can be organizational.
For example, TMU.ac.in.
Where,
- TMU represents the name of the organization.
- ac.in is represented the country domains (ac.in means academia of India).
This example is better understood in the figure below.
Inverse Domain
The inverse domains are those domain name system that is used to map an IP address to a domain name. The example of the inverse domain is shown in the figure below.
