The Digital Research Initiative
The University of North Carolina at Chapel Hill 

What is a domain name?

What is DNS?

DNS (the Domain Name System) is a set of distributed databases containing IP (Internet Protocol) 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

rs.internic.net

instead of a more mysterious string of numbers

198.41.0.5

when using the Internet.
 
 Also from FYI 4 (Answers to Commonly asked "New Internet User" Questions):
The Domain Name System (DNS) is a hierarchical, distributed method of organizing the name space of the Internet. The DNS administratively groups hosts into a hierarchy of authority that allows addressing and other information to be widely distributed and maintained. A big advantage to the DNS is that using it eliminates dependence on a centrally-maintained file that maps host names to addresses.
 
What is a domain name?
Simply put, a domain name is a description of a computer's "location" on the Internet -- it's the "address" of a Web site on the Web. It contains a few components, separated by a period ("dot"). Reading a simple domain name

 

jomc.unc.edu

from left to right (most specific to least specific), the first item (jomc) is the name of the host computer itself, or the hostname. The next item (unc) is the second-level domain name, and is registered by an organization or entity with one of the approved domain name registration services. The last item (edu) is a top-level domain name, and describes the purpose of the organization or entity who owns the second-level name. There are a restricted number of these top-level domain names, and they help describe the sort of business or entity that can be found at that address (e.g., "edu" is for educational institutions).


Subdomains

A domain name may include other components between the hostname and the second-level domain name; these are called subdomains.

 In an e-mail address, the domain name follows the @ symbol, and often consists only of a second-level domain and top-level domain name (unc.edu).

 

Fully Qualified Domain Name (FQDN)

atlas.arc.nasa.gov
 
A Fully Qualified Domain Name (FQDN) is a domain name that includes all higher level domains relevant to the entity named. It's like the complete address, without any shortcuts, for a particular computer, so that anyone anywhere in the world can use that address. For a host, a FQDN would include the string that identifies the particular host, plus all domains of which the host is a part up to and including the top-level domain. For example, atlas.arc.nasa.gov is a Fully Qualified Domain Name for the host at 128.102.128.50. In addition, arc.nasa.gov is the FQDN for the Ames Research Center (ARC) domain under nasa.gov.

Second-level domain and top-level domain

Registration services register second-level domain names only. These names are of the form:  
example.TLD

ibm.com
amy.com
pimples.com
eggs.com
loc.gov
unc.edu
un.org
nando.net

 
where example is the second-level domain name not to exceed 26 characters, and where TLD (top-level domain) is one of the following:
 
ORG   
NET   
EDU   
GOV   
COM
 
The second-level domain name ("unc," "nando," pimples," etc.) is the personalized part of a URL -- sort of like a personalized license plate. Companies and people want that part of the URL to reflect what their Web site is all about, be easy to remember and attract more people to log onto their site.

It is the second-level domain name that can sometimes cause confusion and disputes. Notice that you could have completely different Web sites that all have the same second-level domain name, such as "whitehouse," depending on which top-level domain name you add to it (.gov, .edu, .org, etc.) As a matter of fact, some enterprising folks have capitalized on this fact to get more traffic to their sites, as you can see if you type in www.whitehouse.org or www.whitehouse.com. The correct top-level domain name for the official White House site is ".gov," of course.

New top-level domain names have been proposed, including SHOP, FIRM, and NOM.

 
 
For more information regarding which TLD is appropriate for your purposes, please refer to RFC 1591 - Domain Name System Structure and Delegation and the Registration Template. Note that specific criteria apply for the assignment of each top-level domain.

 Also remember that you have the option to register your name under the US top-level domain on the basis of political geography (entity-name.locality.state-code.US). For more information on the US domain, see RFC 1480 - The US Domain. Visit the US Domain Registry for registration procedures.


 


Go to: Organizational domains

This site made by 
deb 
  This site was created especially for students of the UNC School of Journalism's
JOMC 050 Class, and anyone else who may be interested. 
For more information, please contactdaikat@email.unc.edu 
Last Updated: Mon, 21 Jun 1999 21:22:16 GMT