The Internet uses two addressing schemes--number-based Internet Protocol ( IP ) addresses and text-based Domain Name System ( DNS ) names. An IP address consists of four numbers ranging from 0 to 255, separated by periods. Each machine on the Internet must have a unique IP address. A domain name is a textual address for a location on the Internet. It corresponds to the actual alpha numeric address which the Internet computers can read.
Although IP addresses provide a convenient, compact representation for specifying source and destinations in packets sent across the internet, users prefer to assign machines pronounceable, easily remembered names. A domain name can also create an expectation about who is at that location because it is often a shorthand naming term, or even a trademark or descriptive term with secondary meaning. Further more, the use of domain names has the advantage of shielding network changes from users. Names are often given to machines according to the services that they offer. For example, www normally denotes the name of the web server on the network. Users remember such names rather than specific IP address. In the event that the web server is shifted from one machine to another, only the IP addresses change but not the name. Hence, users can still access the web server using the same name and the change in machines is transparent to the users.
The Internet Domain Name System ( DNS ) is a set of distributed databases containing IP addresses and their corresponding domain names. Each domain name is mapped to a particular numeric address. DNS, with servers located all over the Internet, performs the translation back and forth between names and numbers. This scheme enables users to invoke an easy-to-remember name ( e.g. pknic.net.pk) instead of a more mysterious string of numbers ( e.g. 160.106.7.154) when using the Internet. In the beginning, the original set of machine names used throughout the Internet formed a flat name space. A central site, the Internet Network Information Center ( NIC ), adminstered the namespace and determined whether a new name was appropriate ( i.e. it prohibits obscene names or names that conflicted with existing ones ). As the internet grew, this system was no longer appropriate. Hence, a hierarchical naming scheme is used and the name system is decentralised by delegating authority for parts of the namespace and distributing responsibility for the mapping between names and addresses.In this scheme, PKNIC has the responsibility to manage domain names under .PK
Please note that all links listed below bring you out of this web site.The views expressed at these links do not necessarily reflect the views of PKNIC.
DNS Definition on Webopedia
InterNIC's Background Materials.
DNS Resource Directory.
Some of the material on this page is taken from SGNIC's page
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