The Domain Name System (DNS) is the phonebook of the Internet. The Domain Name System is a hierarchical and decentralized naming system for computers, services, or other resources connected to the Internet or a private network. The Domain Name System resolves the names of internet sites with their underlying IP addresses adding efficiency and even security in the. The Domain Name System (or DNS) converts human readable domain names ( like: www. Domain Name Server (DNS) is a standard protocol that helps Internet users discover websites using human readable addresses. The domain name system (DNS) connects URLs with their IP address.