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DNS Organizational (Generic) Top Level Domains and Authorities
(Page 2 of 4)
Original Generic TLDs
The initial deployment of DNS featured
a set of seven top-level domains that are in the standard called generic
TLDs. The idea was that each company or organization could choose a
name within one of these TLDs; they were generic enough
that every organization would find a place that suited them. I prefer
to call them organizational, because they divide the generic
portion of the name space by organization type. The initial TLDs and
their original intended organization types were:
- .ARPA: A temporary domain used many years
ago for transition to DNS. Its name refers to the ARPAnet, the precursor
of the modern Internet (in turn named for the United States Defense
Advanced Research Projects Agency, ARPA). Today this domain is used
for reverse
name resolution.
- .COM: Corporations and businesses.
- .EDU: Universities and other educational
organizations.
- .GOV: Government agencies.
- .MIL: Military organizations.
- .NET: Organizations that implement, deal
with or manage networking technologies and/or the Internet.
- .ORG: Other organizations that don't fit
into any of the classifications above.
At first glance this seems like a
reasonable way to cover the organizations of the world. However, since
the .ARPA domain is temporary, this left only six categories
for all other organizations. Also, the TLDs weren't all used as was
originally foreseen; for example, the .GOV and .MIL domains were not
used for all types of government and military organizations, but primarily
for the United States federal government and military. .EDU ended up
being used only for universities, again in the United States.
This left only three common top-level
domains.COM, .NET and .ORGfor almost all other groups and
companies that wanted to use the organizational hierarchy. Since there
were only three such TLDs, they quickly became very crowded,
especially the .COM domain. A new fourth domain, .INT for international
organizations, was added fairly soon to the original seven, but it too
was only for a small number of organizations, such as international
standards bodies. Despite the handful of organizational TLDs, there
is no doubt that they have been much more popular than the geopolitical
ones. I explain some of the reasons for this in the
next topic.
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Version 3.0 - Version Date: September 20, 2005
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