A domain name server is similar to a phone book. It tells the Internet programs (e.g. web browsers) where to go by translating the domain name into an Internet (IP) address. All Internet Service Providers (ISPs) have their own Domain Name Servers. You need 2 Domain Name Server names to specify who is hosting your web site.  More technically, A Domain Name Server is a computer with software that converts the alphanumeric Internet addresses (like www.wmirchi.com) into its numeric IP address 69.73.173.58. Domain Name Servers also communicate with each other to respond to queries. Your domain has to be registered with a Domain Name Server for it to be possible for other computers to reach it with the alphanumeric address.