Game Development Reference
In-Depth Information
Table 19.3 Top-Level Domains
TLD
Description
.edu
Educational institutions, mainly in the U.S. (reserved)
.gov
United States government (reserved)
.int
International organizations (reserved)
.mil
United States military (reserved)
.com
Commercial (open for general use)
.net
Networks (open for general use)
.org
Organizations (open for general use)
the United Kingdom, and .cn is used for mainland China. Funny, the Pacific island of
Tuvalu that sits midway between Hawaii and Australia got lucky and pulled .tv as its
TLD. The television industry has made excellent use of these addresses.
As you can tell from Table 19.3, some of these TLDs are restricted and either man-
aged by ICANN or somehow sponsored by an authority agreed upon to manage
assigning unique names within their domain. The open, general-use TLDs like .com,
.net, and .org are managed by ICANN.
Domain names within these top-level domains are issued by ICANN or another
sponsoring authority. When you register for a domain name, you have to provide
all kinds of information, but the really important piece of information is the primary
name server. The primary name server is the IP address of the computer that retains
the authoritative version of your domain name. It propagates this information to
other name servers all over the Internet. Name servers generally update themselves
every few hours. Any new or changed domain name takes a few days to register
with enough name servers to be resolved quickly by anyone on the Internet.
I
'
ll show you how to use the sockets API to find Internet addresses in just a bit.
There are a few useful programs you
'
ll find installed on virtually any computer,
UNIX or Windows. You
ll use them for checking Internet connectivity and other use-
ful things. They are listed in Table 19.4.
'
