A domain name is the way to identify and locate computer connection to the Internet. A domain must be unique i.e. in two organizations on the Internet can have the same domain name.
A domain name contains two or more components separated by period “dots”. Each computer on the Internet is identified by unique IP address. A domain name is a name that identifies one or more IP address.
For example: http://www.google.com
The top level domains are classified into three categories:
The organizational/generic domain consists of three characters code which indicates the primary function of the organizations or their generic behaviour.
The most country used to-level domain are:
- .com – commercial organizations
- .edu – Educational institutions
- .gov – Government agencies
- .org – Organizations
- .net – Network organizations
- .int – International institutions
The country domain consists of two characters which represents different countries/regions all round the world.
These code have been standardized by ISO.
Country domain are:
- . in – India
- . us – United States
- . cn – China
- . au – Australia
- . it – Italy
- . jp – Japan
- . fr – france
The reverse domain is a special domain named in-addr.apra that is used to translate the IP address to Fully Qualified Domain Name.
Each domain name has a corresponding IP address.
Because the Internet is on IP addresses, not domain name, every web server requires a domain Name System (DNS) server to translate domain name into IP addresses.