The Domain Name System (DNS) is the addressing and communications system by which computers connected to the Internet locate each other. Every time an Internet-connected user types in a domain name address, for example www.galegroup.com, the DNS translates this information into a numeric format that can be used to locate other computers on the Internet. This addressing system requires that each computer connected to the Internet have a unique numeric address or Internet Protocol (IP) address. As with most addressing systems (e.g., postal), it is necessary that each IP address be unique.

When an Internet user types in a domain name address, a DNS server (also called a name server; a computer acting as a switching node or post office for the rest of the network) takes that address and translates it into the appropriate numeric IP address. Machines...