Appendix D: Internet Addresses and Domains
Everyone who has watched television, listened to the radio, or surfed the web in the last half-dozen years is familiar with Internet addresses or, more precisely, Uniform Resource Locators (URLs). In fact, these addresses have become so commonplace that many companies now include them, often in place of telephone numbers, as the primary contact information in their advertisements.
An Internet address is actually the verbal translation, or domain name, of a numeric Internet Protocol (IP) address, which represents a unique computer location on the Internet. For example, when the domain name
nces.ed.gov
is keyed into a web browser, the browser asks a server for the actual IP address (in this case, 165.224.221.98), which tells the browser how to get to the site. Users generally are not even aware that these numbers exist and, for almost all operations, use the shorthand Internet address rather than the numeric IP address.
An Internet address is broken into several different segments
separated by periods. The address segments are read in backwards
order to determine the location of the server. The first component
of an Internet address is the top-level domain (TLD), which identifies
the nature of the address owner's business. The TLD most people
are familiar with is .com ("dot com"), short for commercial.
In addition to .com, there are several other generic TLDs,
including .org, .edu, and .net, as well as country-specific
TLDs such as .us and .uk. The rules for using a
particular TLD vary; for example, virtually anyone can get a
.com address, but, for the most part, .edu addresses
are available only to institutions of higher education.
The following table identifies a few of the TLDs that are currently available. New domains are being added constantly.
Top-Level Domains
|
|
Restrictions |
.com |
None - Anyone can register. Originally restricted
to for-profit companies. |
.net |
None - Anyone can register. Originally for
network infrastructure Companies only. |
.org |
None - Anyone can register. Originally for
nonprofits only. |
.edu |
Limited to institutions of higher education
(except for grand-fathered institutions). |
.gov |
United States federal and state governments
only. |
.jp |
Japan's country code. Limited to organizations,
institutions, and individuals in Japan. |
.name |
None - Available to anyone who wants to
register a name domain (e.g., john_smith). |
.mil |
United States military only. |
.kids |
For noncommercial children's content. Not
yet available. |
.biz |
None - Anyone can register. |
.info |
None - Anyone can register. |
.us |
None - Anyone can register. The .us
domain is the United States country code. Originally limited
to a geographic system of naming ( www.name.state.us
), but being reformed. |
.tv |
Tuvalu's country code (an island nation
in the South Pacific). No restrictions. Widely used for television-related
industry. |
The second-level domain (SLD) is the portion of the URL that identifies
the owner of the IP address. The rules for SLDs are even less regulated
than those for TLDs. Some TLDs, such as .com, have no restrictions
at the second level, so virtually anything can be registered. Others
have significant SLD restrictions, such as .us, which requires
state identifiers at the second level.
Starting from the TLD and working backwards, the Internet address
provides information about the address owner. Using the example
nces.ed.gov, it can be determined that the address owner
(TLD) is
- .gov, meaning it is affiliated with the U.S. government;
- .ed.gov, meaning it is part of the U.S. Department of
Education (SLD); and
- nces.ed.gov, the National Center for Education Statistics
at the U.S. Department of Education.
Similar rules apply as more and more domains are added to an address. The drawback to increasing the levels of information within an Internet address is that the address can become unwieldy. The more levels in the address, the more difficult it is to remember. School districts have been traditionally sequestered in the
.us
domain, and they consequently often have web addresses that can be hard to recall from memory.
When choosing a domain name, one should exercise judgment in determining
whether a short and simple or longer and more descriptive name is
appropriate, and then check to see if it is available for use. Companies
that sell domain names for profit quickly snatch up simple domain
names. To check the availability of a domain name or to register
a name, one should go to any online domain registrar, such as
www.register.com
or www.networksolutions.com.
The cost of registering and maintaining a domain name is approximately
$35 per year.
Multiple addresses/domain names can be registered for a single web site for
a variety of reasons. For example, General Electric, for access
to the same site, registered both www.generalelectric.com
and www.ge.com. An education agency or district can likewise
register multiple addresses for its web site; however, only a single
address should be advertised to minimize confusion among staff,
parents, and the public. A district may choose to register different
addresses in order to convert a long domain name to a shorter one
or to guarantee that an alternate address will remain available
for use by the district at a future date. More importantly, the
registration of potentially competing or confusing addresses prevents
them from being used by someone else.
|