Domain Name System server. A computer that keeps a database of domain names and their corresponding IP addresses. When a computer sends a domain name to a DNS server, the server returns the IP address for that domain. The Domain Name System is a mechanism used in the Internet or Intranet for translating names to host computers into addresses. DNS allows host computers not directly on the Internet to have registered names in the same style. DNS allows you to use the Internet without remembering long lists of numbers.