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Top-level domain

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History and Evolution of Top-Level Domains
– Top-level domain space originally organized into three main groups: Countries, Categories, and Multiorganizations
– Additional temporary group consisted of only the initial DNS domain, .arpa, for transitional purposes
– Responsibility for management of most top-level domains delegated to specific organizations by ICANN
– ICANN operates the Internet Assigned Numbers Authority (IANA) and maintains the DNS root zone
– Authoritative list of current TLDs in the root zone published at the IANA website
– The first TLD, .arpa, was established in 1985 for infrastructure purposes
– The number of TLDs has significantly increased over the years, allowing for more diverse naming options
– In 2012, ICANN introduced a program to expand the number of gTLDs, resulting in the creation of hundreds of new TLDs
– The introduction of non-Latin TLDs in 2010 marked a significant milestone in making the internet more inclusive
– TLDs have undergone various policy changes and updates to ensure their effective management and operation

Types of Top-Level Domains
– Infrastructure top-level domain (ARPA) managed by IANA for various purposes
– Generic top-level domains (gTLD) with three or more characters
– Generic restricted top-level domains (grTLD) managed under official ICANN accredited registrars
– Sponsored top-level domains (sTLD) proposed and sponsored by private agencies or organizations
– Country-code top-level domains (ccTLD) established for countries or territories
– IDN ccTLDs are top-level domains with specially encoded domain names displayed in language-native scripts

Administration and Policies of Top-Level Domains
– ICANN is responsible for the administration and coordination of TLDs, including the allocation of new TLDs
– Policies and guidelines are in place to regulate the registration and use of TLDs
– Some TLDs have specific eligibility requirements, such as .edu for educational institutions and .gov for government entities
– The IANA root zone database maintains a list of all TLDs and their associated information
– Special-use domain names, such as .example and .test, are reserved for documentation and testing purposes

Issues and Challenges Related to Top-Level Domains
– Name collision occurs when a TLD used in a private network conflicts with a public TLD
– Dotless domains, which lack a dot between the TLD and the domain name, have raised concerns due to potential security and stability issues
– The introduction of new gTLDs has raised debates about trademark infringement and brand protection
– The management and control of TLDs have been subject to discussions regarding internet governance and accountability
– TLDs can impact search engine optimization (SEO) and website visibility, making their selection an important consideration for businesses and organizations

Further Reading and External Resources
– ‘Addressing the World: National Identity and Internet Country Code Domains’ edited by Erica Schlesinger Wass provides insights into the cultural connections of ccTLDs
– ‘Ruling the Root’ by Milton Mueller discusses TLDs and domain name policy in a broader context
– The Wikimedia Commons and Wikidata offer resources and media related to TLDs
– The Root Zone Database and IANA TLD List provide comprehensive information about TLDs
– CircleID and ISC offer articles and data on TLDs and their usage

Top-level domain (Wikipedia)

Examples of the over 1,500 TLDs
Example domain Type Sponsoring institution
.arpa Infrastructure Internet Architecture Board; restricted[clarification needed]
.blue Generic Identity Digital Limited; unrestricted[clarification needed]
.ovh Generic OVH SAS; run by AFNIC, unrestricted
.name Restricted generic VeriSign Information Services, Inc.; unrestricted
.ac Country-code Internet Computer Bureau; unrestricted
.zw Country-code Postal and Telecommunications Regulatory Authority of Zimbabwe;run by TelOne Zimbabwe; unrestricted
.aero Sponsored Société Internationale de Télécommunications Aéronautiques; unrestricted
.th Internationalized country-code THNIC

A top-level domain (TLD) is one of the domains at the highest level in the hierarchical Domain Name System of the Internet after the root domain. The top-level domain names are installed in the root zone of the name space. For all domains in lower levels, it is the last part of the domain name, that is, the last non empty label of a fully qualified domain name. For example, in the domain name www.example.com, the top-level domain is .com. Responsibility for management of most top-level domains is delegated to specific organizations by the ICANN, an Internet multi-stakeholder community, which operates the Internet Assigned Numbers Authority (IANA), and is in charge of maintaining the DNS root zone.

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