Domain name is a name given to any network for easiness of reference. Domain refers to a group of computers which are known through a single common name. Somebody needs to transfer these domain names into IP addresses. It is decided on physical location of the web server plus where the domain name is registered. Some generic domain names are following:
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Domain name
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Description
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Com
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Commercial organization
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Edu
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Educational organization
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Gov
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Government organization
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Mil
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Military group
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Org
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Non-profit organization
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Therefore, humans employ domain names while referring to computers on the Internet, while computers work with IP addresses only, that are numeric. DNS was developed like a distributed database. The database has the mappings among the domain names & IP addresses scattered across distinct computers. This DNS was consulted when any message is to be sent to any computer on the Internet. DNS is depending on the formation of the hierarchical domain based naming architecture that is implemented like a distributed database. This is used for mapping host names & email addresses to IP addresses. Each of the organization operates a domain name server which contains the list of all of the computers in that organization along with their IP addresses. While an application program needs to translate a computer's name into the computer's IP address, application becomes client of the DNS. It contacts a domain name server & sends the server an alphabetic computer name then the server returns the accurate IP address. The domain name system works as a directory. A given server does not hold the names & addresses of all probable computers in the Internet. Each of the server stores the name of the computers at only one company or enterprise.