Domain Name Services (DNS) refers to a network service that associates host names that are alphanumeric with their equivalent TCP/IP address. This is done by the means of a standard look-up table.

When surfing the Web, Internet hosts can be referred to by their host names (www.hotmail.com) or by their IP address (201.35.124.12). Internet host names are usually used because they are easier to remember than dotted IP addresses.

Example of how DNS works

Suppose you are surfing the Web and decide to visit the URL www.PetStore.com. When this URL is entered, the Web browser asks the TCP/IP protocol to ask the DNS server for the IP address of www.PetStore.com. When this address is received, the Web browser then connects to the PetStore Web server and downloads the home page.