name server

Definition of name server in The Network Encyclopedia.

What is a Name Server?

A host on the Internet or on a TCP/IP internetwork that can be used to resolve host names into IP addresses. Name servers are an essential component of the Domain Name System (DNS), which provides the namespace of all hosts on the Internet or on a private TCP/IP internetwork. Because of name servers, when you want to access or reference a host on a TCP/IP network, you can use its friendly DNS name instead of its IP address, which is generally harder to remember.

How It Works

The DNS functions as a client/server-based system, with name servers forming the server part and resolvers forming the client part. Each name server has authority over a portion of the DNS namespace called a zone, which means that it should be able to resolve name lookups for hosts located within that zone. Resolvers send name lookups to name servers by passing them the name of a host. The name server performs name resolution by determining which IP address corresponds to the requested host’s name. Name servers can also query each other, so a typical name lookup from a resolver might involve several name servers.

This distributed system of name servers makes it possible to share the load of name resolution among many computers. Just imagine if one machine had to track the name of every host on the Internet!

Within a zone you can have two types of name servers, which allows for fault tolerance and a further sharing of the load:

  • Primary name servers:
    These name servers keep a local file of the information relating to their zone. This local file or DNS database contains resource records, which are mappings of host names to IP addresses for hosts in that zone. A DNS administrator must manually create and maintain the DNS database on a primary name server.

     

  • Secondary name servers:
    These name servers obtain their database of resource records from a master name server, which can be either a primary name server or another secondary name server. The process by which the DNS database is transferred from a master name server to a secondary name server is known as zone transfer.

     

The collection of all name servers on the Internet is used to manage and maintain the DNS namespace of host name to IP address mappings. Name servers can also be used on private TCP/IP internetworks to facilitate network communication.

NOTE

Microsoft’s implementation of a name server in Windows NT, the Microsoft DNS Service, is fully compliant with related Requests for Comments (RFCs) describing the implementation and working of the DNS.

Windows 2000 supports the industry’s extension to DNS with the DNS dynamic update protocol. This protocol is integrated into Active Directory on Windows 2000–based networks and enables the dynamic updating of DNS name servers.

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