Domains
Getting where you want to go can often be one of the more difficult aspects of using networks. The variety of ways that places are named will probably leave a blank stare on your face at first. Don't fret; there is a method to this apparent madness.
If someone were to ask for a home address, they would probably expect a street, apartment, city, province, and postal code. That's all the information the post office needs to deliver mail in a reasonably speedy fashion. Likewise, computer addresses have a structure to them. The general form is:
a persons email address: user@somewhere.domain
a computer's name: somewhere.domain
The user portion is usually the person's account name on the system, though it doesn't have to be. somewhere.domain tells you the name of a system or location, and what kind of organization it is. The trailing domain is often one of the following:
| com | Usually a company or other commercial institution or organization, like Convex Computers (convex.com). |
| edu | An educational institution, e.g. New York University, named nyu.edu. |
| gov | A government site; for example, NASA is nasa.gov. |
| mil | A military site, like the Air Force (af.mil) |
| net | Gateways and other administrative hosts for a network |
| org | This is a domain reserved for private organizations, who don't comfortably fit in the other classes of domains. |
Each country also has its own top-level domain. For example, the us domain includes each of the fifty states. Other countries represented with domains include:
| au | Australia |
| ca | Canada |
| fr | France |
| uk | United Kingdom |
The proper terminology for a site's domain name (somewhere.domain above) is its Fully Qualified Domain Name (FQDN). It is usually selected to give a clear indication of the site's organization or sponsoring agent. For example, the Massachusetts Institute of Technology's FQDN is mit.edu; similarly, Apple Computer's domain name is apple.com. While such obvious names are usually the norm, there are the occasional exceptions that are ambiguous enough to mislead---like vt.edu, which on first impulse one might surmise is an educational institution of some sort in Vermont; not so. It's actually the domain name for Virginia Tech. In most cases it's relatively easy to glean the meaning of a domain name---such confusion is far from the norm.
Last Updated March 27/00