Top-level domain

DNS schema

Top-level domain

A top-level domain (TLD) is one of the domains at the highest level in the hierarchical Domain Name System (DNS) of the Internet. The top-level domain names are installed in the root zone of the name space. For all domains in lower levels, the TLD is the last part of the domain name, that is, the last label of a fully qualified domain name. For example, in the domain name www.example.com, the top-level domain is .com.

Types of TLDs

Top-level domains are mainly classified into three types:

• Country code top-level domains (ccTLDs): These are two-letter domains established for countries or territories, such as .uk for the United Kingdom and .jp for Japan.
• Generic top-level domains (gTLDs): These are the most common type of TLDs and include domains such as .com, .org, and .net.
• Sponsored top-level domains (sTLDs): These are specialized TLDs that have a sponsor representing a specific community that is served by the domain, such as .edu for educational institutions and .gov for governmental entities.

History

The concept of TLDs was first introduced in the early 1980s. The original set of TLDs included .com, .org, .net, .edu, .gov, .mil, and .arpa. Over time, the number of TLDs has expanded significantly to include hundreds of new gTLDs and ccTLDs.

Management

The management of TLDs is overseen by the Internet Corporation for Assigned Names and Numbers (ICANN), which is responsible for coordinating the maintenance and procedures of several databases related to the namespaces of the Internet, ensuring the network's stable and secure operation.

Registration

Domain names within a TLD are registered through domain name registrars, which are accredited by ICANN. Each TLD has an authoritative registry that manages the database of domain names registered under that TLD.

Examples of TLDs

• .com - Commercial entities
• .org - Organizations (non-profit)
• .net - Network infrastructure
• .edu - Educational institutions
• .gov - Governmental entities
• .mil - Military
• .uk - United Kingdom
• .jp - Japan

See also

• Domain Name System
• Internet Corporation for Assigned Names and Numbers
• Country code top-level domain
• Generic top-level domain
• Sponsored top-level domain