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What Is 'DNS'? (What Is Internet Domain Name System?)


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Question: What Is 'DNS'? (What Is Internet Domain Name System?)
Answer: Domain Name System, or DNS, is the fundamental system for assigning named addresses to internet web servers (aka "internet host machines"). Somewhat like international phone numbers, the domain name system helps to give every internet server a memorable and easy-to-spell address. Simultaneously, the domain names keep the really technical IP address invisible for most viewers.

How Does DNS Affect the Everyday User?

DNS affects you in two ways:
  1. Domain names are what you will type to visit a web page. (e.g. www.fbi.gov)
  2. Domain names can be purchased so that you can have your own website somewhere. (e.g. www.paulsworld.co.uk)

Some example internet domain names:

  1. about.com
  2. nytimes.com
  3. navy.mil
  4. harvard.edu
  5. monster.ca
  6. wikipedia.org
  7. japantimes.co.jp
  8. dublin.ie
  9. gamesindustry.biz
  10. spain.info
  11. sourceforge.net
  12. wikipedia.org

Some example registry services that will sell you domain names:

  1. NameCheap.com
  2. GoDaddy.com
  3. Domain.ca

How Domain Names Are Spelled

1) Domain names are organized right to left, with general descriptors to the right, and specific descriptors to the left. It is like family surnames to the right, specific person names to the left. These descriptors are called "domains".
2) The "top level domains" (TLD, or parent domain) is to the far right of a domain name. Mid level domains (children and grandchildren) are in the middle. The machine name, often "www", is to the far left.
3) Levels of domains are separated by periods ("dots").

  • Example 1 above) About is the mid-level domain, .com is the top level domain.

  • Example 7 above) japantimes is the smaller mid-level domain. .co is the larger mid-level domain. .jp is the top level domain.

  • Example 10 above) spain is the mid-level domain, .info is the top level domain.

Tech Trivia Note: Most American servers use three-letter top level domains (e.g. ".com", ".edu"). Countries other than the USA commonly use two letters, or combinations of two letters (e.g. ".au", ".ca", ".co.jp").

A Domain Name is Not the Same as URL
To be technically correct, a domain name is commonly part of a larger internet address called a "URL". A URL goes into much more detail than domain name, providing much more information, including the specific page address, folder name, machine name, and protocol language.

Example Uniform Resource Locator pages, with their domain names bolded:
  1. http://horses.about.com/od/basiccare/a/healthcheck.htm
  2. http://www.nytimes.com/2007/07/19/books/19potter.html
  3. http://www.nrl.navy.mill/content.php?P=MISSION
  4. http://www.fas.harvard.edu/~hsdept/chsi.html
  5. http://jobsearch.monster.ca/jobsearch.asp?q=denver&fn=&lid=&re=&cy=CA
  6. http://en.wikipedia.org/wiki/Conradblack
  7. http://classified.japantimes.co.jp/miscellaneous.htm
  8. http://www.dublin.ie/visitors.htm
  9. http://www.gamesindustry.biz/content_page.php?aid=26858
  10. http://www.spain.info/TourSpain/Destinos/
  11. http://azureus.sourceforge.net/download.php

A Domain Name is Not the Same as IP Address
In the end, a domain name is intended to be a friendly and memorable "nickname" only. The true technical address of a web host is its Internet Protocol Address, or IP Address.

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