The Internet Corporation for Assigned Names and Numbers is a global multistakeholder group and nonprofit organization head-quartered in the United States responsible for coordinating the maintenance and procedures of several databases related to the namespaces and numerical spaces of the Internet, ensuring the Internet's stable and secure operation. ICANN performs the actual technical maintenance work of the Central Internet Address pools and DNS root zone registries pursuant to the Internet Assigned Numbers Authority (IANA) function contract. The contract regarding the IANA stewardship functions between ICANN and the National Telecommunications and Information Administration (NTIA) of the United States Department of Commerce ended on October 1, 2016, formally transitioning the functions to the global multistakeholder community.
In the Internet, a domain name is a string that identifies a realm of administrative autonomy, authority or control. Domain names are often used to identify services provided through the Internet, such as websites, email services and more. As of December 2023, 359.8 million domain names had been registered. Domain names are used in various networking contexts and for application-specific naming and addressing purposes. In general, a domain name identifies a network domain or an Internet Protocol (IP) resource, such as a personal computer used to access the Internet, or a server computer.
The Internet Assigned Numbers Authority (IANA) is a standards organization that oversees global IP address allocation, autonomous system number allocation, root zone management in the Domain Name System (DNS), media types, and other Internet Protocol–related symbols and Internet numbers.
A domain name registry is a database of all domain names and the associated registrant information in the top level domains of the Domain Name System (DNS) of the Internet that enables third party entities to request administrative control of a domain name. Most registries operate on the top-level and second-level of the DNS.
A root name server is a name server for the root zone of the Domain Name System (DNS) of the Internet. It directly answers requests for records in the root zone and answers other requests by returning a list of the authoritative name servers for the appropriate top-level domain (TLD). The root name servers are a critical part of the Internet infrastructure because they are the first step in resolving human-readable host names into IP addresses that are used in communication between Internet hosts.
The domain com is a top-level domain (TLD) in the Domain Name System (DNS) of the Internet. Created in the first group of Internet domains at the beginning of 1985, its name is derived from the word commercial, indicating its original intended purpose for subdomains registered by commercial organizations. Later, the domain opened for general purposes.
.xxx is a sponsored top-level domain (sTLD) intended as a voluntary option for pornographic sites on the Internet. The sponsoring organization is the International Foundation for Online Responsibility (IFFOR). The registry is operated by ICM Registry LLC. The ICANN Board voted to approve the sTLD on 18 March 2011. It went into operation on 15 April 2011.
.us is the Internet country code top-level domain (ccTLD) for the United States. It was established in early 1985. Registrants of .us domains must be U.S. citizens, residents, or organizations – or foreign entities with a presence in the United States or any territory of the United States. Most registrants in the U.S. have registered for .com, .net, .org and other gTLDs, instead of .us, which has primarily been used by state and local governments, even though private entities may also register .us domains. The domain is managed by Registry Services, LLC, a domain name registry, on behalf of the United States Department of Commerce.
AlterNIC was an unofficial, controversial Internet domain name registry that relied on an alternative DNS root. The primary purpose of the project was to challenge the monopoly of InterNIC, the official governing body for generic top-level domains (gTLDs) until the creation of the ICANN in 1998. AlterNIC offered second level domain registration in its own TLDs at lower prices than InterNIC. However, these domain names could only be resolved by name servers that were specifically configured to use the AlterNIC root zone. The project is now defunct; the domain name alternic.net is parked and no longer associated with AlterNIC.
.nu is the Internet country code top-level domain (ccTLD) assigned to the island state of Niue. It was one of the first ccTLDs to be marketed to the Internet at large as an alternative to the gTLDs .com, .net, and .org. Playing on the phonetic similarity between nu and new in English, and the fact that nu means "now" in several northern European languages, it was promoted as a new TLD with an abundance of good domain names available. The .nu domain is now controlled by the Internet Foundation in Sweden amid opposition from the government of Niue.
A country code top-level domain (ccTLD) is an Internet top-level domain generally used or reserved for a country, sovereign state, or dependent territory identified with a country code. All ASCII ccTLD identifiers are two letters long, and all two-letter top-level domains are ccTLDs.
.il is the Internet country code top-level domain (ccTLD) of Israel, administered by the Israel Internet Association and managed by NIC - ISRAEL, which hosts the DNS root server and manages the Israeli Internet Exchange, that supports IPv4 and IPv6.
A sponsored top-level domain (sTLD) is one of the categories of top-level domains (TLDs) maintained by the Internet Assigned Numbers Authority (IANA) for use in the Domain Name System of the Internet, alongside country-code top-level domains (ccTLD) and generic top-level domains (gTLD).
.ky is the Internet country code top-level domain (ccTLD) for the Cayman Islands. The code was chosen as other possible options had already been allocated. Registration was limited to residents and registered companies in the Cayman Islands with a local address, but this restriction was removed in September 2015. The Cayman Islands also has the international three-letter code CYM and has won a bid to be awarded the .cym domain in a future expansion of the top-level domain space.
.so is the internet country code top-level domain (ccTLD) for Somalia. After a long absence, the .so domain was officially relaunched on November 1, 2010, by .SO Registry, which is regulated by the nation's Ministry of Posts and Telecommunications. It was launched through various accredited registrars around the world.
.me is the Internet country code top-level domain (ccTLD) for Montenegro.
A geographic top-level domain is any of an unofficial group of top-level domains in the Domain Name System of the Internet using the name of or invoking an association with a geographical, geopolitical, ethnic, linguistic or cultural community. The IANA does not recognize these domains as their own group within the Root Zone Database, rather classifying them as generic top-level domains.
.ss is the designated country code top-level domain (ccTLD) for South Sudan in the Domain Name System of the Internet. It is derived from the ISO 3166-1 alpha-2 code for South Sudan, which is SS. According to CIO East Africa, the TLD was allocated on 10 August 2011 following the country's declaration of independence from Sudan. The TLD was registered on 31 August 2011, but not added to the DNS root zone and was thus not operational. It was approved at the ICANN Board meeting on 27 January 2019 and was added to the DNS root zone on 2 February 2019.
.brussels is a generic top-level domain for Brussels, Belgium. Registry DNS Belgium, who are also responsible for .be, got permission to operate this domain and execute these at the end of 2014, together with .vlaanderen.
United States Minor Outlying Islands 