.dd .dd .dd was the assigned country code top-level domain (ccTLD) for the German Democratic Republic (East Germany). 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: '. In accordance with IANA policy, .dd was therefore available to be assigned as the country code top-level domain (ccTLD) for East Germany. However, this was never done, and so .dd was never added to the root nameservers. Its only use was internally at the universities of Jena and Dresden. With the reunification of Germany, East Germany became
Country code top-level domain will not be reassigned for at least 50 years, and the replacement of RFC 3066 by RFC 4646 for country codes used in language tags in 2006. The previous ISO 3166-1 code for Yugoslavia, YU, was removed by ISO on 2003-07-23, but the yu ccTLD remained in operation. Finally, after a two-year transition to Serbian rs and Montenegrin me, the .yu domain was phased out in March 2010. Australia was originally assigned the oz country code, which was later changed to au with the .oz domains moved to .oz.au. An internationalized country code top-level domain (IDN ccTLD) is a top-level