As the number of hosts on the Internet grew, the traffic generated by the update process increased, as well as the size of the HOSTS file.The need for a new system, which would offer features such as scalability, decentralized administration, support for various data types, became more and more obvious.The Domain Name System introduced in 1984 became this new system.
The Domain Name System is implemented as a hierarchical and distributed database containing various types of data, including host names and domain names.
The names in a DNS database form a hierarchical tree structure called the domain namespace.
DNS supports hierarchical names and allows registration of various data types in addition to host name to IP address mapping used in HOSTS files.
Because the DNS database is distributed, its potential size is unlimited and performance is not degraded when more servers are added.
DNS Domain Name Hierarchy The previous figure shows how Microsoft is assigned authority by the Internet root servers for its own part of the DNS domain namespace tree on the Internet.
DNS clients and servers use queries as the fundamental method of resolving names in the tree to specific types of resource information.Windows Server 2003 components that require name resolution will attempt to use this DNS server before attempting to use the previous default Windows name resolution service, Windows Internet Name Service (WINS).Typically, Windows Server 2003 DNS is deployed in support of Active Directory directory service.The implementation of DNS — Berkeley Internet Name Domain (BIND) — was originally developed for the 4.3 BSD UNIX Operating System.The Microsoft implementation of DNS became a part of the operating system in Microsoft Windows NT Server 4.0.This information is provided by DNS servers in query responses to DNS clients, who then extract the information and pass it to a requesting program for resolving the queried name.