The Domain Name System (DNS) is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities.
The Domain Name System is an essential component of the functionality of most Internet services because it is the Internet’s primary directory service.
A name server is a computer hardware or software server that implements a network service for providing responses to queries against a directory service. It translates an often humanly-meaningful, text-based identifier to a system-internal, often numeric identification or addressing component.
This service is performed by the server in response to a service protocol request.