.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 The ISO 3166-1 code "DD" was withdrawn in 1990.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
Single-letter second-level domain of confusion with country code top-level domains and must be reserved, according to the gTLD Registry Agreement, pending agreement on a process for releasing them after appropriate measures have been taken. Two-letter .com domain names were never reserved. It was possible for anyone to register them in the very early years of the Internet (from 1985 to 1998). The first company to own an active two-letter domain was Hewlett-Packard. Since 1998 all permutations of the 26 × 26 = 676 .com domains have been registered and (barring the very unlikely event of a lapse in registration) they can only be