Domains

Zen and the Art of the Internet

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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, state, and zip 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 person's email address on a computer: 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 (it does not
mean all of the hosts in a network). {The Matrix, 111.  One such
gateway is near.net.}
 
org
This is a domain reserved for private organizations, who don't
comfortably fit in the other classes of domains.  One example is the
Electronic Frontier Foundation named eff.org.
 
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 The United Kingdom.  These also have sub-domains of things like
ac.uk for academic sites and co.uk for commercial ones.