What is a domain?
The term domain can refer either to a local subnetwork or to
descriptors for sites on the Internet (e.g.,
Local subnetwork domains
On a local area network (LAN), a domain is a subnetwork made up of a group of clients and servers under the control of one central security database. Within a domain, users authenticate once to a centralized server known as a domain controller, rather than repeatedly authenticating to individual servers and services. Individual servers and services accept the user based on the approval of the domain controller.
Indiana University's domain is ADS or
ads.iu.edu. To be precise, IU runs an Active
Directory, the most advanced type of domain for domain
controllers running Windows 2000 or later. There are many
administrative differences between Active Directories and earlier
domain types, but for the user the experience is mostly the same.
On the Internet, a domain is part of every network address,
including web site addresses, email addresses, and addresses for other
Internet protocols such as FTP, IRC, and SSH. All devices sharing a
common part of an address, or URL, are said to be in the
same domain. In the address
indiana is the domain,
people is a directory
in that domain, and
address.shtml is a file in the
To obtain a domain, you must purchase it from a domain registrar. You can choose a registrar from the list of accredited registrars.
Internet domains are organized by level. Most people are familiar with
the Top Level Domains (TLDs) of
.org. TLDs are the most general
and basic part of the URL. There are actually many top level
domains. Every country is assigned one; see the complete list of
country code Top Level Domains (ccTLDs). Click the
in the top row of links.
Category domains called generic TLDs (gTLDs) are also available. These
domains are described on the Internet Assigned Numbers
Authority gTLD page. Click the
gTLDs link in the top row of links.
The governing body for domain names is called ICANN (Internet Corporation For Assigned Names and Numbers), a non-profit corporation charged with overseeing the creation and distribution of TLDs.
Last modified on January 25, 2013.