Editing Country code top-level domain (section)

==Relation to ISO 3166-1==
{{see also|ISO 3166-1}}
{{blockquote|The IANA is not in the business of deciding what is and what is not a country. The selection of the ISO 3166 list as a basis for country code top-level domain names was made with the knowledge that ISO has a procedure for determining which entities should be and should not be on that list.|[[Jon Postel]]|RFC 1591<ref>{{cite journal|url=http://tools.ietf.org/html/rfc1591#section-4|id=RFC&nbsp;1591|title=Domain Name System Structure and Delegation|date=March 1994|first=Jon|last=Postel|doi=10.17487/RFC1591|journal=Network Working Group|author-link=Jon Postel|access-date=2008-06-22|archive-date=2010-09-13|archive-url=https://web.archive.org/web/20100913011853/http://tools.ietf.org/html/rfc1591#section-4|url-status=live|language=en|url-access=subscription}}</ref>}}

===Unused ISO 3166-1 codes===
Almost all current ISO 3166-1 codes have been assigned and do exist in DNS.
However, some of these are effectively unused. In particular, the ccTLDs for the Norwegian dependency [[Bouvet Island]] (<code>[[.bv|bv]]</code>) and the designation [[Svalbard and Jan Mayen]] (<code>[[.sj|sj]]</code>) do exist in DNS, but no subdomains have been assigned, and it is [[Norid]] policy to not assign any at present. Two [[France|French]] territories—<code>[[.bl|bl]]</code> ([[Saint Barthélemy]]) and <code>[[.mf|mf]]</code> ([[Saint Martin (France)|Saint Martin]])—{{As of|2008|alt=still}} await local assignment by France's government.

The code <code>[[.eh|eh]]</code>, although eligible as ccTLD for [[Western Sahara]], has never been assigned and does not exist in [[Domain Name System|DNS]]. Only one subdomain is still registered in <code>[[.gb|gb]]</code><ref>{{cite web|url=https://dnstools.ws/lookup/dra.hmg.gb|title=DNS loookup for dra.hmg.gb|year=2010|access-date=2010-07-03|archive-date=2022-08-08|archive-url=https://web.archive.org/web/20220808185902/https://dnstools.ws/lookup/dra.hmg.gb/ANY/|url-status=dead|language=en}}</ref> (ISO 3166-1 for the [[United Kingdom]]), and no new registrations are being accepted for it. Sites in the United Kingdom generally use<code>[[.uk|uk]]</code> (see below).

The former [[.um]] ccTLD for the [[United States Minor Outlying Islands|U.S. Minor Outlying Islands]] was removed in April 2008. Under RFC 1591 rules, [[.um]] is eligible as a ccTLD on request by the relevant governmental agency and local Internet user community.

===ASCII ccTLDs not in ISO 3166-1===
Several ASCII ccTLDs are in use that are not ISO 3166-1 two-letter codes. Some of these codes were specified in older versions of the ISO list.
* <code>[[.uk|uk]]</code> (United Kingdom): The ISO 3166-1 code for the United Kingdom is GB (Great Britain). However, the [[JANET]] network had already selected <code>uk</code> as a top-level identifier for its pre-existing [[JANET NRS|Name Registration Scheme]], and this was incorporated into the DNS root. <code>[[.gb|gb]]</code> was assigned with the intention of a transition, but this never occurred and the use of <code>uk</code> is now entrenched.<ref name=Mueller2002>{{cite book|first=Milton|last=Mueller|year=2002|title=Ruling the Root: Internet governance and the taming of cyberspace|page=79|publisher=MIT Press|location=Cambridge, MA|isbn=9780262632980|url=https://books.google.com/books?id=sMKmdJq7iE0C&pg=PA79|access-date=2020-11-10|archive-date=2021-10-08|archive-url=https://web.archive.org/web/20211008111747/https://books.google.com/books?id=sMKmdJq7iE0C&pg=PA79|url-status=live|language=en}}</ref>
* <code>[[.su|su]]</code> This obsolete ISO&nbsp;3166 code for the [[Soviet Union]] was assigned when the Soviet Union still existed; moreover, new <code>su</code> registrations are accepted.
* <code>[[.ac|ac]]</code> ([[Ascension Island]]): This code is a vestige of [[Internet Assigned Numbers Authority|IANA's]] decision in 1996 to allow the use of codes reserved in the [[ISO 3166-1 alpha-2]] reserve list for use by the [[Universal Postal Union]]. The decision was later reversed, with Ascension Island now the sole outlier. (Three other ccTLDs, <code>[[.gg|gg]]</code> ([[Bailiwick of Guernsey|Guernsey]]), <code>[[.im|im]]</code> ([[Isle of Man]]) and <code>[[.je|je]]</code> ([[Jersey]]) also fell under this category from 1996 until they received corresponding ISO 3166 codes in March 2006.)
* <code>[[.eu|eu]]</code> ([[European Union]]): On September 25, 2000, [[ICANN]] decided to allow the use of any two-letter code in the [[ISO 3166-1]] reserve list that is reserved for all purposes. Only EU currently meets this criterion. Following a decision by the EU's Council of Telecommunications Ministers in March 2002, progress was slow, but a [[domain name registry|registry]] (named [[EURid]]) was chosen by the [[European Commission]], and criteria for allocation set: ICANN approved <code>[[.eu|eu]]</code> as a ccTLD, and it opened for registration on 7 December 2005 for the holders of prior rights. Since 7 April 2006, registration is open to all in the European Economic Area.

===Historical ccTLDs===
ccTLDs may be removed if that country ceases to exist. There are three ccTLDs that have been deleted after the corresponding 2-letter code was withdrawn from ISO 3166-1: <code>[[.cs|cs]]</code> (for [[Czechoslovakia]]), <code>[[.zr|zr]]</code> (for [[Zaire]]) and <code>[[.tp|tp]]</code> (for [[East Timor]]). There may be a significant delay between withdrawal from ISO 3166-1 and deletion from the DNS; for example, ZR ceased to be an ISO 3166-1 code in 1997, but the <code>zr</code> ccTLD was not deleted until 2001. Other ccTLDs corresponding to obsolete ISO 3166-1 codes have not yet been deleted. In some cases they may never be deleted due to the amount of disruption this would cause for a heavily used ccTLD. In particular, the Soviet Union's ccTLD <code>[[.su|su]]</code> remains in use more than twenty years after SU was removed from ISO 3166-1.

The historical country codes <code>[[.dd|dd]]</code> for the [[German Democratic Republic]] and <code>yd</code> for [[South Yemen]] were eligible for a ccTLD, but not allocated; see also <code>[[.de|de]]</code> and <code>[[.ye|ye]]</code>.

The temporary reassignment of country code <code>cs</code> ([[Serbia and Montenegro]]) until its split into <code>[[.rs|rs]]</code> and <code>[[.me|me]]</code> ([[Serbia]] and [[Montenegro]], respectively) led to some controversies<ref>{{cite web|title=IAB input related to the .cs code in ISO&nbsp;3166|date=2003-09-24|first=Leslie|last=Daigle|publisher=[[Internet Architecture Board|IAB]]|url=https://www.iab.org/documents/correspondence-reports-documents/docs2003/2003-09-25-icann-cs-code/|access-date=2008-06-22|archive-date=2008-07-05|archive-url=https://web.archive.org/web/20080705023649/http://www.iab.org/documents/correspondence/2003-09-25-icann-cs-code.html|url-status=live|language=en}}</ref><ref>{{cite web|title=IAB comment on stability of ISO 3166 and other infrastructure standards|date=2003-09-24|first=Leslie|last=Daigle|publisher=[[Internet Architecture Board|IAB]]|url=http://www.iab.org/documents/correspondence/2003-09-25-iso-cs-code.html|access-date=2008-06-22|archive-date=2008-07-05|archive-url=https://web.archive.org/web/20080705024112/http://www.iab.org/documents/correspondence/2003-09-25-iso-cs-code.html|url-status=dead|language=en}}</ref> about the stability of ISO 3166-1 country codes, resulting in a second edition of ISO&nbsp;3166-1 in 2007 with a guarantee that retired codes will not be reassigned for at least 50&nbsp;years, and the replacement of RFC&nbsp;3066 by RFC&nbsp;4646 for country codes used in [[language tag]]s in 2006.

The previous ISO&nbsp;3166-1 code for [[Yugoslavia]], YU, was removed by ISO on 23&nbsp;July 2003, but the <code>[[.yu|yu]]</code> ccTLD remained in operation. Finally, after a two-year transition to Serbian <code>[[.rs|rs]]</code> and Montenegrin <code>[[.me|me]]</code>, the .yu domain was phased out in March&nbsp;2010.

Australia was originally assigned the <code>[[.au#Historic second-level domains|oz]]</code> country code, which was later changed to <code>[[.au|au]]</code> with the <code>.oz</code> domains moved to <code>.oz.au</code>.