Domain Name Service (DNS)

Domain Name Service (DNS) – RFC 1035
Domain Name Service resolves hostnames, specifically Internet names. You do not have to use DNS, you can just type the IP address of any device you want to communicate with. An IP address identifies hosts on a network and the internet as well. However, DNS was designed to make our lives easier. DNS allows you to use a domain name to specify an IP address. The goal of domain names is to provide a mechanism for naming resources in such a way that the names are usable in different hosts, networks, protocol families, internets, and administrative organizations. Name servers manage two kinds of data. The first kind of data held in sets called zones; each zone is the complete database for a particular "pruned" sub tree of the domain space. This data is called authoritative. A name server periodically checks to make sure that its zones are up to date, and if not, obtains a new copy of updated zones

Reference:
Information science Institute. (1981). Domain Name Service. Retrieved August 22, 2009, from http://www.ietf.org/rfc/rfc1035.txt?number=1035