A domain extension, commonly known as a top level domain, can be defined as the group of letters that follow the last dot in a URL. It is the last part of an Internet domain name. Before delving into the concept of domain extensions, we must understand what domain names are. They are strings of characters that are used by Internet servers to identify network entities. They are managed by the domain name system, which provides electronic mail routing information and a protocol that enables interaction between clients and severs.
The top-level domain extensions have been classified as infrastructure top-level domains that are managed by the Internet Assigned Numbers Authority and country-code top-level domains that are specific to a country or territory. Sponsored top-level domains, sponsored by private agencies and generic top-level domains that are open for registration throughout the world, are other types of top-level domains.
The popularly known domain extensions are .com, .org, .edu, and .gov. Let us look at these and some other popular ones.
.com: The .com extension stands for 'commercial'. It was established in 1985 and is used by several commercial and non-commercial websites around the world. It is the most popular top-level domain.
.org: The .org domain extension stands for organization. It was established in January 1985, with the purpose of being given to organizations that do not fulfill the requirements of other generic top-level domains. Organizations all over the world can register for the .org domain extension. It can also be used by individuals. However, individuals can also use domain extensions such as .name and .info. There are no specific requirements for the registration of the .org extension.
.edu: It stands for education and is widely used by educational institutions across the United States. Not all websites using the .edu extension are educational institutions. Some of them are museums or research organizations linked with education.
.gov: It is a sponsored domain extension that is used by government entities in the United States. Federal agencies in the United States use the .fed domain extension. The Department of Defense and its subordinate organizations use the .mil extension.
The .net extension is also one of the earliest top-level domains in use. Established in 1985, it is currently being managed by VeriSign. Similar to the .org domain, the .net domain also has no requirements for registration. It ranks third in the list of most popular top-level domains.
The .info and .name domain extensions meant for personal use and other domain extensions like .aero, .biz, and .pro are some of the relatively new domains added to the list of generic top-level domains. They were developed and began to be used in the period between 2000 and 2002. The .aero domain stands for 'airplane' and is used by businesses associated with aviation. .biz is used by businesses. It was designed with the aim of providing businesses with an option to the .com domain. The .pro generic top-level domain can be used by qualified professionals.
.jobs, .mobi, and .travel are some of the more recent domains developed by the Internet Corporation for Assigned Names and Numbers (ICANN). Company websites intended at seeking employees and dealing with issues related to the company employment use the .jobs domain extension. The .mobi domain extension is used by mobile devices gaining access to the Internet. Supported by Google, Microsoft, the GSM Association, and many prominent telecom industries, .mobi is one of the very important domain extensions. The .travel domain is meant to be used by travel agents and tourism agencies.
The .ae used by the United Arab Emirates, .au used by Australia, .asia used by organizations and individuals located in the Asia-Pacific region, .uk used by the United Kingdom, .in by India, .pk by Pakistan and .us used by the state and local governments in the United States are some examples of country-code domains.
To summarize, domain name extensions are those last few letters of an Internet domain name that give it an identity. Thanks to them, millions of websites have a distinguished existence.