Domain nameA character-string based identifier (name) of an Internet domain. Domain names are intended to ease the designation of individual nodes and resources deployed on top of them from human readability viewpoint. All the Internet domains are unified by a hierarchy. A fully qualified domain name is a dot-separated series of domains, such as domain3.domain2.domain1, where domain1 is the topmost-level domain. The Domain Name System (DNS) ensures the matching between domain names and IP addresses.