The registrar requires that you have at least two DNS servers, and that their IP addresses not be in a single block of 256 addresses. (Reported May 2001.) If all your computers are in the same block, you will be forced to obtain third-party DNS service. This requirement is bad practice, because it ignores the costs of third-party DNS service. Consider obtaining a .com name instead.
The registrar also requires that you make zone transfers available to 193.6.27.63, 193.225.12.65, and 193.225.12.71. (Reported May 2001.) This requirement is bad practice: typical sites should not even set up TCP service, let alone zone transfers.
The registrar also requires that mail service be available for postmaster@yourname.hu where yourname.hu is the delegated name. (Reported May 2001.)