The Domain Name System (DNS) is a hierarchical and decentralized naming system for computers, services, or other resources connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. (Source). It is an Internet's equivalent of a phone book that maintains a directory of domain names and translates it into Internet Protocol (IP) addresses. Domain Name System is necessary because domain names are easy for people to remember, unlike computers or machines which accesses websites based on IP addresses.