What is a historical ccTLD?
A historical ccTLD is a country code top-level domain whose two letter code is withdrawn from the ISO 3166-1 standard country code list that the ccTLDs are based on. This is usually due to the country the ccTLD was connected to either changing its name or being split up and no longer existing as it was. When this happens the ccTLD is often phased out and then deleted from the Domain Name System (DNS), meaning it can no longer be used.
The following is a list of historical ccTLDs:
- .CS was the ccTLD for Czechoslovakia. Today .CZ is used for the Czech Republic and .SK for the Slovak Republic.
- .DD was the available ccTLD for East Germany, though it was never officially assigned to it. Following the reunification of Germany, .DE, which already existed, became the only ccTLD used.
- .GB was supposed to be the ccTLD for the United Kingdom based on the ISO 3166-1 standard country codes; however .UK was created and delegated as its ccTLD before the completion of the ISO list. After .GB was created, it never caught on and today, it is no longer possible to register domains under it.
- .OZ was originally assigned as Australia's ccTLD. After .AU was delegated as Australia's ccTLD instead, the namespace on .OZ was moved to .OZ.AU; however today this is no longer actively used and is considered a historical second-level domain (SLD).
- .SU was the ccTLD for the Soviet Union; however, unlike the others on this list, this historical ccTLD is still in use today.
- .TP was the ccTLD for East Timor. Today, .TL is used because the ISO 3166-1 standard country code was changed to "TL" for East Timor.
- .YU was the ccTLD for Yugoslavia. Today there are six different ccTLDs that are used to represent six different countries: .BA for Bosnia and Herzegovina, .HR for Croatia, .ME for Montenegro, .MK for Macedonia, .RS for Servia, and .SI for Slovenia.
- .ZR was the ccTLD for Zaire, which is now known as the Democratic Republic of Congo with the ccTLD of .CD.
There are also some ccTLDs based on the ISO 3166-1 country code list that were created, but have not been used for various reasons.