Domain Extension

A domain extension is the suffix seen at the end of a URL or e-mail address and each extension signifies a particular category to which a website belongs. The .com, .org and .net are examples of domain extensions which are accessible to anyone from anywhere in the world. On the Internet, domain extensions are assigned and administered by ICANN (the Internet Corporations for Assigned Names and Numbers), which is a non-profit international body.

Every domain name consists of two parts — name and extension. Based on the classification of IANA (Internet Assigned Numbers Authority), three categories of top level domains exist — generic top-level domains, country code top-level domains, and .arpa, a special top-level domain for Internet infrastructure. Top level domains are referred to as first level domains.

Country code top level domain extensions (ccTLD), over 240 number, represent specific countries, and usually consist of two characters. In 1980, generic top level domains were developed to be used by particular categories and these are represented using three or more characters. Some of the country code top-level extensions are .ae for United Arab Emirates, .bd for Bangladesh, .cl for Chile, .de for Germany, and more.

Generic top level domain extensions are .org, .com,.net, .mil, .edu, .int, .gov, .biz, .name, .info, .pro, .aero, .museum, .coop, .tel, .mobi, .jobs, .travel, .post, .cat, etc. In the present world, the .com extension is the most commonly and widely used extension. Following are some of the generic top level domain extensions used by various entities:

.com — commercial entities
.org — non-profit organizations
.net -Internet infrastructure and network providers
.edu/.ac — educational institutions
.mil — US military
.gov — reserved for US intergovernmental organizations
.int — international organizations
.biz — business web sites
.name — used by individuals or families for personal use
.info — unrestricted extension for informational websites
.pro — for professional organizations and credentialed professionals
.aero — air-transport industry websites
.museum — for museums
.coop — cooperative associations

Domain extensions are operated and controlled by various registries recognized by ICANN. This division of work among various agencies enables the smooth functioning of the Internet.