.dk is the country code top-level domain (ccTLD) for Denmark.
The supervision of the .dk top-level domain, is handled exclusively by DK Hostmaster.
Any new .dk domain name has to be applied for via an approved registrator. Then the domain name applicant can ask the registrator to manage his domain name or do it directly with DK Hostmaster. Registrations of domain names with the characters æ, ø, å, ö, ä, ü, and/or é are also allowed.
In mid 1988 DKnet was connected to the emerging DENet, the government-sponsored research network established in late 1987 now known as forskningsnettet, run and maintained by UNI-C.
In January 1989 DKUUG made a name agreement ("navneaftalen") with the coordinators of the three other networks then working in Denmark, a national experimental X.400 net (EAN from University of British Columbia), EARN and DECnet, concerning the .dk domain. They agreed to share it, hiding from the users which network they were connected to, and nullifying the use of pseudo-domains like .uucp or second-level domains like gov.uk, thereby creating a practice that has been enforced ever since.
DKUUG established a separate organization named "DK Hostmaster" in 1991, to administrate the .dk domain, following the creation of WWW.
By early 1992 UNI-C via DENet (an acronym for "Danish Educational Network") serviced all the Universities in Denmark, and DIKU had no need for DKnet anymore. Thus DKUUG, with DKnet, moved to Symbion Science Park where they received their own international lines and started to lease these to companies, and modem connections to private consumers. The growing business quickly overshadowed the organization's own economy, forcing the creation of a separate company. In 1993, DKnet Aps, a genuine ISP and Denmark's first, was established as a limited liability company.
In 1996, with the establishment of the Danish Research Network, the name "DENet" was used for the commercial part of the network and changed to be an acronym for "Dansk Erhvervs Net", i.e. Danish Business Network.
Tele Danmark initially refused, and the group together formed the organisation Foreningen af Internetleverandører (FIL), and threatened to go directly to IANA to counter what they saw as a bona fide Tele Danmark monopoly. Tele Denmark agreed and FIL became the authority registered by IANA for the .dk domain, while the nominal and practical administration remained the responsibility of DKnet A/S. In June 1996 they signed a one-year contract about the practice and rules concerning the .dk domain, which would later be renewed for another year.
In December 1997 Tele Danmark announced that from the beginning of 1998 they would start collecting a yearly fee (of 340 DKK ex moms) for every registered domain name, via DK Hostmaster. This caused a stir in FIL's members, as they had not been informed. While there had been talks about some sort of fee to DK Hostmaster to cover its expenses, no review of DK Hostmaster’s actual budget was available since it was financially all but a part of Tele Danmark. This was therefore seen by FIL as abuse of power and profit making via the supposedly non-profit DK Hostmaster organization. It was later revealed that it was the board of directors of FIL (later fired) that had granted Tele Danmark the right to set the price that they wanted, without asking its members.
As a consequence of this Tele Danmark announced in March 1998 that the commercial parts in DK-net A/S was moved to Tele Denmark Internet and DK-net A/S, with its only remaining asset, DK Hostmaster, was renamed to "DK Hostmaster A/S", and put up for sale. Tele Danmark encouraged a larger forum or group comprising more than just telecom and internet companies (like FIL) to form and buy it, because the Internet now had a much broader appeal. This caused yet another stir in FIL who flat out rejected that Tele Denmark had the right to sell something it did not own.