A domain name registry is a database of all

domain names 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. D ...

and the associated registrant information in the top level domains of the

Domain Name System The Domain Name System (DNS) is a hierarchical and distributed name service that provides a naming system for computers, services, and other resources on the Internet or other Internet Protocol (IP) networks. It associates various information ...

(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 registry operator, sometimes called a network information center (NIC), maintains all administrative data of the domain and generates a zone file which contains the addresses of the nameservers for each domain. Each registry is an organization that manages the registration of domain names within the domains for which it is responsible, controls the policies of domain name allocation, and technically operates its domain. It may also fulfill the function of a

domain name registrar A domain name registrar is a company, person, or office that manages the reservation of Internet domain names. A domain name registrar must be accredited by a generic top-level domain (gTLD) Domain name registry, registry or a country code top-l ...

, or may delegate that function to other entities. Domain names are managed under a hierarchy headed by the

Internet Assigned Numbers Authority The Internet Assigned Numbers Authority (IANA) is a standards organization that oversees global IP address allocation, Autonomous system (Internet), autonomous system number allocation, DNS root zone, root zone management in the Domain Name Syste ...

(IANA), which manages the top of the DNS tree by administrating the data in the

root nameserver 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 ...

s. IANA also operates the int registry for intergovernmental organizations, the arpa zone for protocol administration purposes, and other critical zones such as

root-servers.net 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 ...

. IANA delegates all other domain name authority to other domain name registries and a full list is available on their web site.

Country code top-level domain 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 tw ...

s (ccTLD) are delegated by IANA to national registries such as

DENIC DENIC eG is the manager of the .de domain, the country-code top-level domain for Germany. It was founded in 1996 and is organised as a non-regulated not-for-profit cooperative. DENIC provides the Domain Name System (DNS) as well as registrat ...

in Germany and Nominet in the United Kingdom.

Operation

Some name registries are government departments (e.g., the registry for India ''gov.in''). Some are co-operatives of Internet service providers (such as

) or not-for profit companies (such as

Nominet UK Nominet UK is currently delegated by IANA to be the manager of the .uk domain name. Nominet directly manages registrations directly under .uk, and some of the second level domains .co.uk, .org.uk, .sch.uk, .me.uk, .net.uk, .ltd.uk and .plc.uk. ...

). Others operate as commercial organizations, such as the US registry (''nic.us''). The allocated and assigned domain names are made available by registries by use of the

WHOIS WHOIS (pronounced as the phrase "who is") is a query and response protocol that is used for querying databases that store an Internet resource's registered users or assignees. These resources include domain names, IP address blocks and autonomo ...

or its successor

Registration Data Access Protocol The Registration Data Access Protocol (RDAP) is a Computer networking, computer network communications protocol standardized by a working group at the Internet Engineering Task Force in 2015, after experimental developments and thorough discussion ...

and via their domain name servers. Some registries sell the names directly, and others rely on separate entities to sell them. For example, names in the .com top-level domains are in some sense sold "wholesale" at a regulated price by

VeriSign Verisign, Inc. is an American company based in Reston, Virginia, that operates a diverse array of network infrastructure, including two of the Internet's thirteen root nameservers, the authoritative registry for the , , and generic top-level d ...

, and individual

s sell names "retail" to businesses and consumers.

Policies

Allocation policies

Historically, domain name registries operated on a

first-come-first-served Queueing theory is the mathematical study of waiting lines, or queues. A queueing model is constructed so that queue lengths and waiting time can be predicted. Queueing theory is generally considered a branch of operations research because th ...

system of allocation but may reject the allocation of specific domains on the basis of political, religious, historical, legal or cultural reasons. For example, in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, between 1996 and 1998,

InterNIC InterNIC, known as the Network Information Center (NIC) until 1993, was the organization primarily responsible for Domain Name System (DNS) domain name allocations and X.500 directory services. From its inception in 1972 until October 1, 1991 ...

automatically rejected domain name applications based on a list of perceived obscenities and sanctioned hate-based domains. However, enforcement was not always consistent. In 2017, a request to register the domain fucknazis.com was first granted and then denied. A challenge to this ruling resulted in elimination of the “

seven dirty words The seven dirty words are seven English language profanity words that American comedian George Carlin first listed in his 1972 "Seven Words You Can Never Say on Television" monologue. The words, in the order Carlin listed them, are: " shit", " ...

” policy for registration of US Domain Names based on

first amendment First most commonly refers to: * First, the ordinal form of the number 1 First or 1st may also refer to: Acronyms * Faint Images of the Radio Sky at Twenty-Centimeters, an astronomical survey carried out by the Very Large Array * Far Infrared a ...

grounds. Registries may also control matters of interest to their local communities; for example, the German, Japanese and Polish registries have introduced internationalized domain names to allow use of local non-

ASCII ASCII ( ), an acronym for American Standard Code for Information Interchange, is a character encoding standard for representing a particular set of 95 (English language focused) printable character, printable and 33 control character, control c ...

characters.

Dispute policies

Domains that are registered with

ICANN The Internet Corporation for Assigned Names and Numbers (ICANN ) is a global multistakeholder group and nonprofit organization headquartered in the United States responsible for coordinating the maintenance and procedures of several dat ...

registrars, generally have to use the Uniform Domain-Name Dispute-Resolution Policy (

UDRP The Uniform Domain-Name Dispute-Resolution Policy (UDRP) is a process established by the Internet Corporation for Assigned Names and Numbers (ICANN) for the resolution of disputes regarding the registration of internet domain names. The UDRP curre ...

), however, Germany's

requires people to use the German civil courts, and

deals with intellectual property and other disputes through its own dispute resolution service.

Third-level domains

Domain name registries may also impose a system of

third-level domain In the Domain Name System (DNS) hierarchy, a subdomain is a domain that is a part of another (main) domain. For example, if a domain offered an online store as part of their website it might use the subdomain. Overview The Domain Name System ...

s on users. DENIC, the registry for Germany ( .de), does not impose third level domains. AFNIC, the registry for France ( .fr), has some third level domains, but not all registrants have to use them. Many ccTLDs have moved from compulsory third or fourth-level domain to the availability of registrations of second level domains. Among them are .us (April 2002), .mx (May 2009), .co (March 2010), and .uk (June 2014).

References