.dd part of the Federal Republic of Germany, which had already been assigned the ccTLD .de. The ISO 3166-1 code "DD" was withdrawn in 1990. .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
Generic top-level domain gTLD as of March 2018 exceeds 1,200 domains. Overall, IANA distinguishes the following groups of top-level domains: The initial set of generic top-level domains, defined by RFC 920 in October 1984, was a set of "general purpose domains": com, edu, gov, mil, org. The net domain was added with the first implementation of these domains. The com, net, and org TLDs, despite their originally-specific goals, are now open to use for any purpose. In November 1988, another TLD was introduced, int. This TLD was introduced in response to NATO's request for a domain name which adequately reflected its character as