What is a domain?

The term domain can refer either to a local subnetwork or to descriptors for sites on the Internet (e.g., www.legitimedomains.com).

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.

Internet domains
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 www.indiana.edu/people/address.shtml, indiana is the domain, people is a directory in that domain, and address.shtml is a file in the directory.

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 .com, .edu, .net, and .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 ccTLDs link 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.

What is Top Level Domain (TLD) & Second Level Domain (SLD)?

TLD's (Top Level Domains) are the top level in the hierarchy of the Domain Name System. In the example "domain.com" the ".com" is the Top Level Domain.
TLD's in general are often referred to as the Namespace. For example the domain name domain.info is part of the .info namespace.

There are three types of TLD's.

1. The most common are gTLD's (generic Top Level Domains), such as .Com, .Net, .Org., and now .Info. Anyone is authorized to register domain names in a TLD namespace.

2. rTLD's (restricted Top Level Domains) such as .Biz and .US only allow people who meet certain criteria to register domain names, such as Business related sites for .Biz.

3. ccTLD's (country code Top Level Domains) such as .in (India) are individually assigned to countries and their dependencies. Each country sets specific registration criteria.

Every TLD Registry - generic, restricted, or country code - has its own prices, policies, and procedures that Registrants are subject to.

Second Level Domain
In the Domain Name System the level of the hierarchy underneath the Top Level Domains is called "second level domains." In the example domain name "Domain.com" the "Domain" part is the second level domain. Second level domain names are what you register in the Top Level Domain Registry database using the services of the Registrar.

Top-level domains

The top-level domains (TLDs) are the highest level of domain names of the Internet. They form the DNS root zone of the hierarchical Domain Name System. Every domain name ends in a top-level or first-level domain label.

When the Domain Name System was created in the 1980s, the domain name space was divided into two main groups of domains. The country code top-level domains (ccTLD) were primarily based on the two-character territory codes of ISO-3166 country abbreviations. In addition, a group of seven generic top-level domains (gTLD) was implemented which represented a set of categories of names and multi-organizations. These were the domains GOV, EDU, COM, MIL, ORG, NET, and INT.

During the growth of the Internet, it became desirable to create additional generic top-level domains. As of October 2009, there are 21 generic top-level domains and 250 two-letter country-code top-level domains. In addition, the ARPA domain serves technical purposes in the infrastructure of the Domain Name System.

During the 32nd International Public ICANN Meeting in Paris in 2008, ICANN started a new process of TLD naming policy to take a "significant step forward on the introduction of new generic top-level domains." This program envisions the availability of many new or already proposed domains, as well a new application and implementation process. Observers believed that the new rules could result in hundreds of new top-level domains to be registered.

Why do I need a Domain Name?

There are numerous uses for Domain names.

- Domain names are used to establish a unique identity in internet. Organisations choose a Domain name that corresponds to their company name. For instance, our web site is legitimedomains.com. Anyone thinking about establishing a presence on the Internet should register a Domain name. You can register domain now & use it later.

- Domain names can be used to give you a unique, permanent email address. You can create

- To maximize the chances of a successful Internet presence and have a global reach.