DNS

From HostPedia

Domain Name system (DNS) associates domain names with hostnames. It functions as a phone book for the internet by translating readable domain names to hostnames, and by that enables the use of human readable internet addresses such as "www.hostpedia.org" instead of forcing users the use of IP addresses like "19.292.88.77" which are much harder to remember. It also stores other information such as the list of mail exchange servers that accept email for a given domain.