Top-level domain
Encyclopedia
A top-level domain is one of the domains
at the highest level in the hierarchical Domain Name System
of the Internet
. 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 label of a fully qualified domain name. For example, in the domain name www.example.com, the top-level domain is .com
(or .COM, as domain names are not case-sensitive). Management of most top-level domains is delegated to responsible organizations by the Internet Corporation for Assigned Names and Numbers (ICANN), which operates the Internet Assigned Numbers Authority
(IANA) and is in charge of maintaining the DNS root zone
.
Originally, the top-level domain space was organized into three main groups, Countries, Categories, and Multiorganizations. An additional temporary group consisted only of the initial DNS domain, arpa
, intended for transitional purposes toward the stabilization of the domain name system.
Countries are designated in the Domain Name System by their two-letter ISO country code
; there are exceptions, however (e.g., .uk
). This group of domains is therefore commonly known as country-code top-level domains (ccTLD). Since 2009, countries with non-Latin based alphabets or scripting systems may apply for internationalized country code top-level domain names, which are displayed in end-user applications in their language-native script or alphabet, but use a Punycode
-translated ASCII domain name in the Domain Name System.
The Categories group has become known as the generic top-level domain
s. Initially this group consisted of GOV
, EDU
, COM
, MIL
, ORG
, and NET
.
In the growth of the Internet, it became desirable to create additional generic top-level domains. Some of the initial domains' purposes were also generalized, modified, or assigned for maintenance to special organizations affiliated with the intended purpose.
As a result, IANA today distinguishes the following groups of top-level domains:
In addition, a group of internationalized domain name
(IDN) top-level domains has been installed under test
for testing purposes in the IDN development process.
The authoritative list of currently existing TLDs in the root zone is published at the IANA website at http://www.iana.org/domains/root/db/.
, in its language-native script or alphabet
, such as the Arabic alphabet
, or a non-alphabetic writing system
, such as Chinese character
s. IDN ccTLDs are an application of the internationalized domain name
(IDN) system to top-level Internet domains assigned to countries, or independent geographic regions.
ICANN started to accept applications for IDN ccTLDs in November 2009, and installed the first set into the Domain Names System in May 2010. The first set was a group of Arabic names for the countries of Egypt, Saudi Arabia, and the United Arab Emirates. By May 2010, 21 countries had submitted applications to ICANN, representing 11 scripts.
was the first Internet top-level domain. It was intended to be used only temporarily, aiding in the transition of traditional ARPANET host names to the domain name system. However, after it had been used for reverse DNS lookup
, it was found impractical to retire it, and is used today exclusively for Internet infrastructure purposes such as in-addr.arpa for IPv4 and ip6.arpa for IPv6 reverse DNS resolution, uri.arpa and urn.arpa for the Dynamic Delegation Discovery System
, and e164.arpa for telephone number mapping
based on NAPTR DNS records. For historical reasons, arpa
is sometimes considered to be a generic top-level domain.
created the nato
domain for use by NATO. NATO considered none of the then existing TLDs as adequately reflecting their status as an international organization
. Soon after this addition, however, InterNIC also created the int
TLD for the use by international organizations in general, and persuaded NATO to use the second level domain nato.int instead. The nato TLD, no longer used, was finally removed in July 1996.
Other historical TLDs are cs
for Czechoslovakia
(now cz
for Czech Republic
and sk
for Slovak Republic), dd
for East Germany (using de
after reunification of Germany), yu
for SFR Yugoslavia
(now: ba
for Bosnia and Herzegovina
, hr
for Croatia
, me
for Montenegro
, mk
for Macedonia
, rs
for Serbia
and si
for Slovenia
), and zr
for Zaire
(now cd
for Democratic Republic of the Congo
). In contrast to these, the TLD su
has remained active despite the demise of the Soviet Union
that it represents.
discussed and finally introduced aero
, biz
, coop
, info
, museum
, name
, and pro
TLDs, site owners argued that a similar TLD should be made available for adult and pornographic websites to settle the dispute of obscene content on the Internet and the responsibility of US service providers under the US Communications Decency Act
of 1996. Several options were proposed including xxx
, sex and adult. As of June 2010, the .xxx TLD has received initial approval from the ICANN
, based upon a proposal by the sponsoring agency for this TLD, a Florida-based company called ICM Registry.
An older proposal consisted of seven new gTLDs: arts, firm, info
, nom, rec, shop
, and web
. Later biz
, info
, museum
, and name
covered most of these old proposals.
During the 32nd International Public ICANN Meeting in Paris in 2008, ICANN started a new process of TLD naming policy to take a "significant step forward on the introduction of new generic top-level domains." This program envisions the availability of many new or already proposed domains, as well a new application and implementation process. Observers believed that the new rules could result in hundreds of new gTLDs to be registered. Proposed TLDs include free
, music
, shop
, berlin
, wien
and nyc
.
s, and the high application costs associated with TLDs, contributed to the creation of alternate DNS roots with different sets of top-level domains. Such domains may be accessed by configuration of a computer with alternate or additional (forwarder) DNS servers or plugin modules for web browsers. Browser plugins detect alternate root domain requests and access an alternate domain name server for such requests.
, CSNET
, UUCP
or other networks, existed that were in widespread use among computer professionals and academic users, that were incompatible with the Internet and exchanged e-mail with the Internet via special e-mail gateways. For relaying purposes on the gateways, messages associated with these networks were labeled with suffixes such as bitnet
, oz
, csnet
, or uucp
, but these domains did not exist as top-level domains in the public Domain Name System
of the Internet.
Most of these networks have long since ceased to exist, and although UUCP still gets significant use in parts of the world where Internet infrastructure has not yet become well-established, it subsequently transitioned to using Internet domain names, so pseudo-domains now largely survive as historical relics. One notable exception is the 2007 emergence of SWIFTNet
Mail, which uses the swift pseudo-domain.
The top-level pseudo domain local
is required by the Zeroconf
protocol. It is also used by many organizations internally, which may become a problem for those users as Zeroconf becomes more popular. Both site and internal have been suggested for private usage, but no consensus has emerged.
The anonymity network Tor
has a top-level pseudo-domain onion
, which can only be reached with a Tor client because it uses the Tor-protocol (onion routing
) to reach the hidden service to protect the anonymity of users.
Domain name
A domain name is an identification string that defines a realm of administrative autonomy, authority, or control in the Internet. Domain names are formed by the rules and procedures of the Domain Name System ....
at the highest level in the hierarchical Domain Name System
Domain name system
The Domain Name System is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities...
of the Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
. The top-level domain names are installed in the root zone
DNS root zone
A DNS root zone is the top-level DNS zone in a Domain Name System hierarchy. Most commonly it refers to the root zone of the largest global DNS, deployed for the Internet. Ultimate authority over the DNS root zone rests with the US Department of Commerce NTIA...
of the name space. For all domains in lower levels, it is the last part of the domain name
Domain name
A domain name is an identification string that defines a realm of administrative autonomy, authority, or control in the Internet. Domain names are formed by the rules and procedures of the Domain Name System ....
, 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
.com
The domain name com is a generic top-level domain in the Domain Name System of the Internet. Its name is derived from commercial, indicating its original intended purpose for domains registered by commercial organizations...
(or .COM, as domain names are not case-sensitive). Management of most top-level domains is delegated to responsible organizations by the Internet Corporation for Assigned Names and Numbers (ICANN), which operates the Internet Assigned Numbers Authority
Internet Assigned Numbers Authority
The Internet Assigned Numbers Authority is the entity that oversees global IP address allocation, autonomous system number allocation, root zone management in the Domain Name System , media types, and other Internet Protocol-related symbols and numbers...
(IANA) and is in charge of maintaining the DNS root zone
DNS root zone
A DNS root zone is the top-level DNS zone in a Domain Name System hierarchy. Most commonly it refers to the root zone of the largest global DNS, deployed for the Internet. Ultimate authority over the DNS root zone rests with the US Department of Commerce NTIA...
.
Originally, the top-level domain space was organized into three main groups, Countries, Categories, and Multiorganizations. An additional temporary group consisted only of the initial DNS domain, arpa
.arpa
The domain name arpa is a top-level domain in the Domain Name System of the Internet. It is used exclusively for technical infrastructure purposes...
, intended for transitional purposes toward the stabilization of the domain name system.
Countries are designated in the Domain Name System by their two-letter ISO country code
ISO 3166-1 alpha-2
ISO 3166-1 alpha-2 codes are two-letter country codes defined in ISO 3166-1, part of the ISO 3166 standard published by the International Organization for Standardization , to represent countries, dependent territories, and special areas of geographical interest...
; there are exceptions, however (e.g., .uk
.uk
.uk is the Internet country code top-level domain for the United Kingdom. , it is the fourth most popular top-level domain worldwide , with over 9.5 million registrations....
). This group of domains is therefore commonly known as country-code top-level domains (ccTLD). Since 2009, countries with non-Latin based alphabets or scripting systems may apply for internationalized country code top-level domain names, which are displayed in end-user applications in their language-native script or alphabet, but use a Punycode
Punycode
In computing, Punycode is an instance of a general encoding syntax by which a string of Unicode characters is transformed uniquely and reversibly into a smaller, restricted character set....
-translated ASCII domain name in the Domain Name System.
The Categories group has become known as the generic top-level domain
Generic top-level domain
A generic top-level domain is one of the categories of top-level domains maintained by the Internet Assigned Numbers Authority for use in the Domain Name System of the Internet....
s. Initially this group consisted of GOV
.gov
The domain name gov is a sponsored top-level domain in the Domain Name System of the Internet. The name is derived from government, indicating its restricted use by government entities in the United States. The gov domain is administered by the General Services Administration , an independent...
, EDU
.edu
The domain name edu is a sponsored top-level domain in the Domain Name System of the Internet. The "domain is intended for accredited post-secondary educational U.S. institutions" and this intention is strictly enforced....
, COM
.com
The domain name com is a generic top-level domain in the Domain Name System of the Internet. Its name is derived from commercial, indicating its original intended purpose for domains registered by commercial organizations...
, MIL
.mil
The domain name mil is the sponsored top-level domain in the Domain Name System of the Internet for the United States Department of Defense and its subsidiary or affiliated organizations. The name is derived from military. It was one of the first top-level domains, created in January 1985.The...
, ORG
.org
The domain name org is a generic top-level domain of the Domain Name System used in the Internet. The name is derived from organization....
, and NET
.net
The domain name net is a generic top-level domain used in the Domain Name System of the Internet. The name is derived from network, indicating its originally intended purpose for organizations involved in networking technologies, such as Internet service providers and other infrastructure companies...
.
In the growth of the Internet, it became desirable to create additional generic top-level domains. Some of the initial domains' purposes were also generalized, modified, or assigned for maintenance to special organizations affiliated with the intended purpose.
As a result, IANA today distinguishes the following groups of top-level domains:
- country-code top-level domains (ccTLD): Two letter domains established for countriesCountryA country is a region legally identified as a distinct entity in political geography. A country may be an independent sovereign state or one that is occupied by another state, as a non-sovereign or formerly sovereign political division, or a geographic region associated with a previously...
or territories. With some historical exceptions, the code for any territory is the same as its two-letter ISO 3166ISO 3166ISO 3166 is a standard published by the International Organization for Standardization . It defines codes for the names of countries, dependent territories, special areas of geographical interest, and their principal subdivisions . The official name of the standard is Codes for the representation...
code. - internationalized country code top-level domains (IDN ccTLD).
- generic top-level domainGeneric top-level domainA generic top-level domain is one of the categories of top-level domains maintained by the Internet Assigned Numbers Authority for use in the Domain Name System of the Internet....
s (gTLD): Top-level domains with three or more characters- unsponsored top-level domains: domains that operate directly under policies established by ICANN processes for the global Internet community.
- sponsored top-level domainSponsored top-level domainA sponsored top-level domain is one of the categories of top-level domains maintained by the Internet Assigned Numbers Authority for use in the Domain Name System of the Internet....
s (sTLD): These domains are proposed and sponsored by private agencies or organizations that establish and enforce rules restricting the eligibility to use the TLD. Use is based on community theme concepts.
- infrastructure top-level domain: This group consists of one domain, the Address and Routing Parameter Area.arpaThe domain name arpa is a top-level domain in the Domain Name System of the Internet. It is used exclusively for technical infrastructure purposes...
(ARPA). It is managed by IANA on behalf of the Internet Engineering Task ForceInternet Engineering Task ForceThe Internet Engineering Task Force develops and promotes Internet standards, cooperating closely with the W3C and ISO/IEC standards bodies and dealing in particular with standards of the TCP/IP and Internet protocol suite...
for various purposes specified in the Request for CommentsRequest for CommentsIn computer network engineering, a Request for Comments is a memorandum published by the Internet Engineering Task Force describing methods, behaviors, research, or innovations applicable to the working of the Internet and Internet-connected systems.Through the Internet Society, engineers and...
publications.
In addition, a group of internationalized domain name
Internationalized domain name
An internationalized domain name is an Internet domain name that contains at least one label that is displayed in software applications, in whole or in part, in a language-specific script or alphabet, such as Arabic, Chinese, Russian, Hindi or the Latin alphabet-based characters with diacritics,...
(IDN) top-level domains has been installed under test
.test
The name test is reserved by the Internet Engineering Task Force in RFC 2606 as a domain name that is not intended to be installed as a top-level domain in the global Domain Name System of the Internet for production use....
for testing purposes in the IDN development process.
The authoritative list of currently existing TLDs in the root zone is published at the IANA website at http://www.iana.org/domains/root/db/.
Internationalized country code TLDs
An internationalized country code top-level domain (IDN ccTLD) is a top-level domain with a specially encoded domain name that is displayed in an end user application, such as a web browserWeb browser
A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...
, in its language-native script or alphabet
Alphabet
An alphabet is a standard set of letters—basic written symbols or graphemes—each of which represents a phoneme in a spoken language, either as it exists now or as it was in the past. There are other systems, such as logographies, in which each character represents a word, morpheme, or semantic...
, such as the Arabic alphabet
Arabic alphabet
The Arabic alphabet or Arabic abjad is the Arabic script as it is codified for writing the Arabic language. It is written from right to left, in a cursive style, and includes 28 letters. Because letters usually stand for consonants, it is classified as an abjad.-Consonants:The Arabic alphabet has...
, or a non-alphabetic writing system
Writing system
A writing system is a symbolic system used to represent elements or statements expressible in language.-General properties:Writing systems are distinguished from other possible symbolic communication systems in that the reader must usually understand something of the associated spoken language to...
, such as Chinese character
Chinese character
Chinese characters are logograms used in the writing of Chinese and Japanese , less frequently Korean , formerly Vietnamese , or other languages...
s. IDN ccTLDs are an application of the internationalized domain name
Internationalized domain name
An internationalized domain name is an Internet domain name that contains at least one label that is displayed in software applications, in whole or in part, in a language-specific script or alphabet, such as Arabic, Chinese, Russian, Hindi or the Latin alphabet-based characters with diacritics,...
(IDN) system to top-level Internet domains assigned to countries, or independent geographic regions.
ICANN started to accept applications for IDN ccTLDs in November 2009, and installed the first set into the Domain Names System in May 2010. The first set was a group of Arabic names for the countries of Egypt, Saudi Arabia, and the United Arab Emirates. By May 2010, 21 countries had submitted applications to ICANN, representing 11 scripts.
IDN test domains
In the process of testing internationalized top-level domains, ICANN implemented a set of IDN top-level domains that are translations of the name example.test into each language's script.| DNS name | Link | Script | Language |
|---|---|---|---|
| xn--mgbh0fb.xn--kgbechtv | http://مثال.إختبار | Arabic | Arabic |
| xn--fsqu00a.xn--0zwm56d | http://例子.测试 | Simplified Chinese | Chinese |
| xn--fsqu00a.xn--g6w251d | http://例子.測試 | Traditional Chinese | Chinese |
| xn--hxajbheg2az3al.xn--jxalpdlp | http://παράδειγμα.δοκιμή | Greek | Greek |
| xn--p1b6ci4b4b3a.xn--11b5bs3a9aj6g | http://उदाहरण.परीक्षा | Devanagari | Hindi |
| xn--r8jz45g.xn--zckzah | http://例え.テスト | Kanji, Hiragana, Katakana | Japanese |
| xn--9n2bp8q.xn--9t4b11yi5a | http://실례.테스트 | Hangul | Korean |
| xn--mgbh0fb.xn--hgbk6aj7f53bba | http://مثال.آزمایشی | Perso-Arabic | Persian |
| xn--e1afmkfd.xn--80akhbyknj4f | http://пример.испытание | Cyrillic | Russian |
| xn--zkc6cc5bi7f6e.xn--hlcj6aya9esc7a | http://உதாரணம்.பரிட்சை | Tamil | Tamil |
| xn--6dbbec0c.xn--deba0ad | http://דוגמה.טעסט | Hebrew | Hebrew |
| xn--fdbk5d8ap9b8a8d.xn--deba0ad | http://בײַשפּיל.טעסט | Hebrew | Yiddish |
Infrastructure domain
The domain arpa.arpa
The domain name arpa is a top-level domain in the Domain Name System of the Internet. It is used exclusively for technical infrastructure purposes...
was the first Internet top-level domain. It was intended to be used only temporarily, aiding in the transition of traditional ARPANET host names to the domain name system. However, after it had been used for reverse DNS lookup
Reverse DNS lookup
In computer networking, reverse DNS lookup or reverse DNS resolution is the determination of a domain name that is associated with a given IP address using the Domain Name System of the Internet....
, it was found impractical to retire it, and is used today exclusively for Internet infrastructure purposes such as in-addr.arpa for IPv4 and ip6.arpa for IPv6 reverse DNS resolution, uri.arpa and urn.arpa for the Dynamic Delegation Discovery System
Dynamic Delegation Discovery System
Defined in RFC 3401, RFC 3402, RFC 3403, RFC 3404, and RFC 3405.From RFC 3401:The Dynamic Delegation Discovery System is used to implement lazy binding of strings to data, in order to support dynamically configured delegation systems...
, and e164.arpa for telephone number mapping
Telephone Number Mapping
Telephone number mapping is the process of unifying the telephone number system of the public switched telephone network with the Internet addressing and identification name spaces. Telephone numbers are systematically organized in the E.164 standard, while the Internet uses the Domain Name System...
based on NAPTR DNS records. For historical reasons, arpa
.arpa
The domain name arpa is a top-level domain in the Domain Name System of the Internet. It is used exclusively for technical infrastructure purposes...
is sometimes considered to be a generic top-level domain.
Reserved domains
RFC 2606 reserves the following four top-level domain names to avoid confusion and conflict. They may be used for various specific purposes however, with the intention that these should not occur in production networks within the global domain name system:- example.exampleThe name example is reserved by the Internet Engineering Task Force in RFC 2606 as a domain name that may not be installed as a top-level domain in the Domain Name System of the Internet.-Reserved DNS names:...
: reserved for use in examples - invalid.invalidThe name invalid is reserved by the Internet Engineering Task Force in RFC 2606 as a domain name that may not be installed as a top-level domain in the Domain Name System of the Internet.-Reserved DNS names:...
: reserved for use in obviously invalid domain names - localhost.localhostThe name localhost is reserved by the Internet Engineering Task Force in RFC 2606 as a domain name label that may not be installed as a top-level domain in the Domain Name System of the Internet.-Reserved DNS names:...
: reserved to avoid conflict with the traditional use of localhostLocalhostIn computer networking, localhost is the standard hostname given to the address of the loopback network interface. The name is also a reserved top-level domain name In computer networking, localhost (meaning this computer) is the standard hostname given to the address of the loopback network...
as a hostname - test.testThe name test is reserved by the Internet Engineering Task Force in RFC 2606 as a domain name that is not intended to be installed as a top-level domain in the global Domain Name System of the Internet for production use....
: reserved for use in tests
Historical domains
In the late 1980s InterNICInterNIC
The Internet Network Information Center, known as InterNIC, was the Internet governing body primarily responsible for domain name and IP address allocations from 1972 until September 18, 1998 when this role was assumed by the Internet Corporation for Assigned Names and Numbers...
created the nato
.nato
The domain name nato was a top-level domain in the Domain Name System of the Internet. The domain was added in the late 1980s by InterNIC for the use of NATO, based on the representation that none of the then existing top-level domains adequately reflected their status as an international...
domain for use by NATO. NATO considered none of the then existing TLDs as adequately reflecting their status as an international organization
International organization
An intergovernmental organization, sometimes rendered as an international governmental organization and both abbreviated as IGO, is an organization composed primarily of sovereign states , or of other intergovernmental organizations...
. Soon after this addition, however, InterNIC also created the int
.int
The domain name int is a sponsored top-level domain in the Domain Name System of the Internet. Its name is derived from the word international, characterizing its use for world-wide purposes....
TLD for the use by international organizations in general, and persuaded NATO to use the second level domain nato.int instead. The nato TLD, no longer used, was finally removed in July 1996.
Other historical TLDs are cs
.cs
.cs was for several years the country code top-level domain for Czechoslovakia. However, the country split into the Czech Republic and Slovakia in 1993, and the two new countries were soon assigned their own ccTLDs: .cz and .sk respectively...
for Czechoslovakia
Czechoslovakia
Czechoslovakia or Czecho-Slovakia was a sovereign state in Central Europe which existed from October 1918, when it declared its independence from the Austro-Hungarian Empire, until 1992...
(now cz
.cz
.cz is the country code top-level domain for the Czech Republic. It is administered by CZ.NIC. Registrations must be ordered via accredited domain name registrars.Before the split in 1993 former Czechoslovakia used domain .cs....
for Czech Republic
Czech Republic
The Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest....
and sk
.sk
.sk is the Internet country code top-level domain for Slovakia. It is administered by SK-NIC a.s. Registrations are only allowed to local entities.Before the split in 1993 former Czechoslovakia used domain .cs.-External links:* * *...
for Slovak Republic), dd
.dd
.dd was the assigned country code top-level domain for the German Democratic Republic . It was chosen based on the ISO 3166-1 alpha-2 code for the German Democratic Republic, the letters coming from the German name of the country: ...
for East Germany (using de
.de
.de is the country code top-level domain for the Federal Republic of Germany. DENIC does not require specific second-level domains, as it is the case with the .uk domain range which require .co.uk domain for example.The name is based on the first two letters of the German name for Germany...
after reunification of Germany), yu
.yu
.yu was the Internet country code top-level domain that was assigned to Yugoslavia and was mainly used by the Federal Republic of Yugoslavia and its successor Serbia and Montenegro between 1994 and 2010....
for SFR Yugoslavia
Socialist Federal Republic of Yugoslavia
The Socialist Federal Republic of Yugoslavia was the Yugoslav state that existed from the abolition of the Yugoslav monarchy until it was dissolved in 1992 amid the Yugoslav Wars. It was a socialist state and a federation made up of six socialist republics: Bosnia and Herzegovina, Croatia,...
(now: ba
.ba
.ba is the Internet country code top-level domain for Bosnia and Herzegovina. It is administered by the University Teleinformation Center.It has the following second-level domains:*.web.ba: *.org.ba: Non-profit organizations...
for Bosnia and Herzegovina
Bosnia and Herzegovina
Bosnia and Herzegovina , sometimes called Bosnia-Herzegovina or simply Bosnia, is a country in Southern Europe, on the Balkan Peninsula. Bordered by Croatia to the north, west and south, Serbia to the east, and Montenegro to the southeast, Bosnia and Herzegovina is almost landlocked, except for the...
, hr
.hr
- Details :The .hr domain is administered by CARNet - Croatian Academic and Research Network, via the CARNet DNS Committee which determines policy, and the CARNet DNS Service which handles day-to-day matters. The Committee is composed of members generally associated with the academic community...
for Croatia
Croatia
Croatia , officially the Republic of Croatia , is a unitary democratic parliamentary republic in Europe at the crossroads of the Mitteleuropa, the Balkans, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Croatia covers ...
, me
.me
.me is the Internet country code top-level domain for Montenegro.The .me top level domain replaced the .yu domain previously used by Serbia and Montenegro....
for Montenegro
Montenegro
Montenegro Montenegrin: Crna Gora Црна Гора , meaning "Black Mountain") is a country located in Southeastern Europe. It has a coast on the Adriatic Sea to the south-west and is bordered by Croatia to the west, Bosnia and Herzegovina to the northwest, Serbia to the northeast and Albania to the...
, mk
.mk
.mk is the Internet country code top-level domain for the Republic of Macedonia. It is administered by The Macedonian Academic Research Network .Available domains:* .mk* .com.mk* .org.mk* .net.mk* .edu.mk...
for Macedonia
Republic of Macedonia
Macedonia , officially the Republic of Macedonia , is a country located in the central Balkan peninsula in Southeast Europe. It is one of the successor states of the former Yugoslavia, from which it declared independence in 1991...
, rs
.rs
.rs is the Internet country code top-level domain for Serbia. The domain name registry that operates it is the Register of National Internet Domain Names of Serbia . The letters rs stand for Republic of Serbia....
for Serbia
Serbia
Serbia , officially the Republic of Serbia , is a landlocked country located at the crossroads of Central and Southeast Europe, covering the southern part of the Carpathian basin and the central part of the Balkans...
and si
.si
.si is the Internet country code top-level domain for Slovenia. It is administered by the ARNES, the Academic and Research Network of Slovenia. The registry has reached 80,000 domain names on 19. May 2010-External links:* * *...
for Slovenia
Slovenia
Slovenia , officially the Republic of Slovenia , is a country in Central and Southeastern Europe touching the Alps and bordering the Mediterranean. Slovenia borders Italy to the west, Croatia to the south and east, Hungary to the northeast, and Austria to the north, and also has a small portion of...
), and zr
.zr
.zr is the former Internet country code top-level domain for Zaire. Because Zaire was renamed Democratic Republic of the Congo in 1997, .zr was phased out and .cd took its place. In 2001, .zr was finally terminated.-External links:* , 20 June 2001...
for Zaire
Zaire
The Republic of Zaire was the name of the present Democratic Republic of the Congo between 27 October 1971 and 17 May 1997. The name of Zaire derives from the , itself an adaptation of the Kongo word nzere or nzadi, or "the river that swallows all rivers".-Self-proclaimed Father of the Nation:In...
(now cd
.cd
.cd is the Internet country code top-level domain for the Democratic Republic of Congo. It was created in 1997 as a replacement for the .zr ccTLD, which was phased out and eventually deleted in 2001....
for Democratic Republic of the Congo
Democratic Republic of the Congo
The Democratic Republic of the Congo is a state located in Central Africa. It is the second largest country in Africa by area and the eleventh largest in the world...
). In contrast to these, the TLD su
.su
.su was assigned as the country code top-level domain for the Soviet Union on September 19, 1990. It remains in use today, even though the Soviet Union itself no longer exists, and is administered by the Russian Institute for Public Networks .In 2001, the managers of the domain stated that they...
has remained active despite the demise of the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
that it represents.
Proposed domains
Around late 2000 when ICANNICANN
The Internet Corporation for Assigned Names and Numbers is a non-profit corporation headquartered in Marina del Rey, California, United States, that was created on September 18, 1998, and incorporated on September 30, 1998 to oversee a number of Internet-related tasks previously performed directly...
discussed and finally introduced aero
.aero
.aero is a generic top-level domain used in the Domain Name System of the Internet. It is the first sponsored top-level domain based on a single industrial theme. The aero domain is reserved for companies, organizations, associations, government agencies, and individuals in aviation-related...
, biz
.biz
biz is a generic top-level domain in the Domain Name System of the Internet. It is intended for registration of domains to be used by businesses...
, coop
.coop
The domain coop is a sponsored top-level domain in the Domain Name System of the Internet. It is intended for the use of cooperatives, wholly owned subsidiaries, and other organizations that exist to promote or support co-operatives....
, info
.info
The domain name info is a generic top-level domain in the Domain Name System of the Internet, The name is derived from information indicating that the domain is intended for informative Internet resources, although registration requirements do not prescribe any theme orientation.The info TLD was...
, museum
.museum
museum is a sponsored top-level domain in the Domain Name System of the Internet used exclusively by museums, museum associations, and individual members of the museum profession, as these groups are defined by the International Council of Museums .In joint action with the J...
, name
.name
The domain name "name" is a generic top-level domain in the Domain Name System of the Internet. It is intended for use by individuals for representation of their personal names, nicknames, screen names, pseudonyms, or other types of identification labels....
, and pro
.pro
The domain name pro is a generic top-level domain in the Domain Name System of the Internet. Its name is derived from professional, indicating its intended use by qualified professionals.-History:...
TLDs, site owners argued that a similar TLD should be made available for adult and pornographic websites to settle the dispute of obscene content on the Internet and the responsibility of US service providers under the US Communications Decency Act
Communications Decency Act
The Communications Decency Act of 1996 was the first notable attempt by the United States Congress to regulate pornographic material on the Internet. In 1997, in the landmark cyberlaw case of Reno v. ACLU, the United States Supreme Court struck the anti-indecency provisions of the Act.The Act was...
of 1996. Several options were proposed including xxx
.xxx
.xxx is a sponsored top-level domain intended as a voluntary option for pornographic sites on the Internet. The sponsoring organization is the International Foundation for Online Responsibility . The registry is operated by ICM Registry LLC. The ICANN Board voted to approve the sTLD on March 18,...
, sex and adult. As of June 2010, the .xxx TLD has received initial approval from the ICANN
ICANN
The Internet Corporation for Assigned Names and Numbers is a non-profit corporation headquartered in Marina del Rey, California, United States, that was created on September 18, 1998, and incorporated on September 30, 1998 to oversee a number of Internet-related tasks previously performed directly...
, based upon a proposal by the sponsoring agency for this TLD, a Florida-based company called ICM Registry.
An older proposal consisted of seven new gTLDs: arts, firm, info
.info
The domain name info is a generic top-level domain in the Domain Name System of the Internet, The name is derived from information indicating that the domain is intended for informative Internet resources, although registration requirements do not prescribe any theme orientation.The info TLD was...
, nom, rec, shop
.shop
.shop is a proposed top-level domain for the Internet, submitted to ICANN for approval as a sponsored TLD. It would be restricted to the use of e-commerce on the Internet. It is sponsored by Commercial Connect Inc, an international organization based in the United States, with partners worldwide.-...
, and web
.web
.web is a generic top-level domain operated as a prospective registry, not in the official root, by Image Online Design since 1995. It originated when Jon Postel, then running the top level of the Domain Name System basically single-handedly, proposed the addition of new top-level domains to be...
. Later biz
.biz
biz is a generic top-level domain in the Domain Name System of the Internet. It is intended for registration of domains to be used by businesses...
, info
.info
The domain name info is a generic top-level domain in the Domain Name System of the Internet, The name is derived from information indicating that the domain is intended for informative Internet resources, although registration requirements do not prescribe any theme orientation.The info TLD was...
, museum
.museum
museum is a sponsored top-level domain in the Domain Name System of the Internet used exclusively by museums, museum associations, and individual members of the museum profession, as these groups are defined by the International Council of Museums .In joint action with the J...
, and name
.name
The domain name "name" is a generic top-level domain in the Domain Name System of the Internet. It is intended for use by individuals for representation of their personal names, nicknames, screen names, pseudonyms, or other types of identification labels....
covered most of these old proposals.
During the 32nd International Public ICANN Meeting in Paris in 2008, ICANN started a new process of TLD naming policy to take a "significant step forward on the introduction of new generic top-level domains." This program envisions the availability of many new or already proposed domains, as well a new application and implementation process. Observers believed that the new rules could result in hundreds of new gTLDs to be registered. Proposed TLDs include free
.free
.free is a proposed new top level domain . It is a Sponsored top-level domain intended to be a free top level domain.According to the dotFree Group s.r.o. organization .free will allow every individual to register free domain names under .free Along with TLDs such as .travel, .asia and .eu, .free...
, music
.music
music is a proposed generic top-level domain in the Domain Name System of the Internet, intended for the music community and music web sites....
, shop
.shop
.shop is a proposed top-level domain for the Internet, submitted to ICANN for approval as a sponsored TLD. It would be restricted to the use of e-commerce on the Internet. It is sponsored by Commercial Connect Inc, an international organization based in the United States, with partners worldwide.-...
, berlin
.berlin
.berlin is a proposed new top level domain . It is a Sponsored top-level domain intended to be a top level domain for Berliners.According to the dotBERLIN organization .berlin will allow all Berliners to register their domains under .berlin...
, wien
.wien
.wien is a proposed new top level domain . It is a Sponsored top-level domain intended to be a top level domain for individuals, companies and organizations from Vienna, Austria....
and nyc
.nyc
.nyc is a proposed city-level top-level domain for New York City.The .nyc top-level domain was proposed in 2000 by J. William Semich in an application to ICANN...
.
Alternative DNS roots
ICANN's slow progress in creating new generic top-level domainGeneric top-level domain
A generic top-level domain is one of the categories of top-level domains maintained by the Internet Assigned Numbers Authority for use in the Domain Name System of the Internet....
s, and the high application costs associated with TLDs, contributed to the creation of alternate DNS roots with different sets of top-level domains. Such domains may be accessed by configuration of a computer with alternate or additional (forwarder) DNS servers or plugin modules for web browsers. Browser plugins detect alternate root domain requests and access an alternate domain name server for such requests.
Pseudo-domains
Several networks, such as BITNETBITNET
BITNET was a cooperative USA university network founded in 1981 by Ira Fuchs at the City University of New York and Greydon Freeman at Yale University...
, CSNET
CSNET
The Computer Science Network was a computer network that began operation in 1981 in the United States. Its purpose was to extend networking benefits, for computer science departments at academic and research institutions that could not be directly connected to ARPANET, due to funding or...
, UUCP
UUCP
UUCP is an abbreviation for Unix-to-Unix Copy. The term generally refers to a suite of computer programs and protocols allowing remote execution of commands and transfer of files, email and netnews between computers. Specifically, a command named uucp is one of the programs in the suite; it...
or other networks, existed that were in widespread use among computer professionals and academic users, that were incompatible with the Internet and exchanged e-mail with the Internet via special e-mail gateways. For relaying purposes on the gateways, messages associated with these networks were labeled with suffixes such as bitnet
.bitnet
.bitnet was a pseudo-domain-style suffix used in the late 1980s when identifying a hostname not connected directly to the Internet but possibly reachable through inter-network gateways. In this case, it indicated that the hostname preceding it was reachable via the BITNET network...
, oz
.oz
.oz is a Domain Name System pseudo-top-level domain that is used by MHSnet, the Australian Computer Science Network. .oz domain hosts that are available on the Internet have been migrated to .oz.au...
, csnet
.csnet
.csnet is a hostname suffix that was used for identifying nodes in the Computer Science Network not directly connected to the Internet but reachable through special gateway systems. It was never installed as a top-level domain in the Domain Name System, but parsed in the message routing logic of...
, or uucp
.uucp
The name uucp was a pseudo-domain-style suffix used in the 1980s when identifying a hostname not connected directly to the Internet, but possibly reachable through other inter-network gateways...
, but these domains did not exist as top-level domains in the public Domain Name System
Domain name system
The Domain Name System is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities...
of the Internet.
Most of these networks have long since ceased to exist, and although UUCP still gets significant use in parts of the world where Internet infrastructure has not yet become well-established, it subsequently transitioned to using Internet domain names, so pseudo-domains now largely survive as historical relics. One notable exception is the 2007 emergence of SWIFTNet
Society for Worldwide Interbank Financial Telecommunication
The Society for Worldwide Interbank Financial Telecommunication operates a worldwide financial messaging network which exchanges messages between banks and other financial institutions...
Mail, which uses the swift pseudo-domain.
The top-level pseudo domain local
.local
local is a pseudo-top-level domain used in multicast domain name service of zero configuration networking discovery protocols.Apple's Bonjour implements mDNS, as does Avahi...
is required by the Zeroconf
Zeroconf
Zero configuration networking , is a set of techniques that automatically creates a usable Internet Protocol network without manual operator intervention or special configuration servers....
protocol. It is also used by many organizations internally, which may become a problem for those users as Zeroconf becomes more popular. Both site and internal have been suggested for private usage, but no consensus has emerged.
The anonymity network Tor
Tor (anonymity network)
Tor is a system intended to enable online anonymity. Tor client software routes Internet traffic through a worldwide volunteer network of servers in order to conceal a user's location or usage from someone conducting network surveillance or traffic analysis...
has a top-level pseudo-domain onion
.onion
.onion is a pseudo-top-level domain host suffix designating an anonymous hidden service reachable via the Tor network...
, which can only be reached with a Tor client because it uses the Tor-protocol (onion routing
Onion routing
Onion routing is a technique for anonymous communication over a computer network. Messages are repeatedly encrypted and then sent through several network nodes called onion routers. Like someone unpeeling an onion, each onion router removes a layer of encryption to uncover routing instructions, and...
) to reach the hidden service to protect the anonymity of users.
See also
- Document classificationDocument classificationDocument classification or document categorization is a problem in both library science, information science and computer science. The task is to assign a document to one or more classes or categories. This may be done "manually" or algorithmically...
- List of Internet top-level domains
- Domain hackDomain hackA domain hack is an unconventional domain name that combines domain levels, especially the top-level domain , to spell out the full "name" or title of the domain. Examples include del.icio.us , goo.gl and fold.it...
- Public Suffix ListPublic Suffix ListThe Public Suffix List is a catalog of certain Internet domain name suffixes. A "public suffix" is also known by the older term effective top level domain...
Further reading
- Addressing the World: National Identity and Internet Country Code Domains, edited by Erica Schlesinger Wass (Rowman & Littlefield, 2003, ISBN 0-7425-2810-3) examines connections between cultures and their ccTLDs.
- Ruling the Root by Milton Mueller (MIT Press, 2001, ISBN 0-262-13412-8) discusses TLDs and domain name policy more generally.