Sun Microsystems developed the Domain Name System (DNS) in the early 1980s a more natural way to keep track of Internet addresses. The Internet Protocol (IP) uses Internet address information to deliver mail and other data from computer to computer. Every IP address on the Internet is a series of four numbers separated by periods called dots, such as 126.96.36.199. However, it will be challenging to remember numeric addresses to communicate with someone using electronic mail. The DNS establishes a hierarchy of domains, which are groups of computers on the Internet.
Domain Name System (DNS) is the standard for resolving names to Internet addresses. However, the host’s file still plays a role in name resolution during the booting of a system and as a means to provide LAN resolution when DNS is down. In a nutshell, DNS is a distributed database whose structure looks like the UNIX file system. DNS is a client/server system in which the resolvers query the named servers to find an address record for a domain name. The query process begins with the root name server if the root name server does not know the answer, it returns the address of a name server that knows more details about the domain name. The resolver then queries the new name server. This iterative process continues until a name server responds with the address for the domain name.
The root of the DNS database on the Internet is managed by the Internet Network Information Center (http://www.internic.com ). The top-level domains were assigned organization wise, and by country. DNS is a protocol that can be used on different platforms.