Requirements for Nameservers

Nameservers hosting Icelandic domains (".is" domains) must comply with the following requirements:

1. Nameservers must be correctly registered in DNS (with A and/or AAAA resource records).
2. Nameserver names may only contain ascii letters, digits, hyphen and periods.
3. Nameservers must allow connection to UDP port 53, and to TCP port 53 as well (see RFC5966 ).
4. For nameservers within the ".is" zone, the following also applies:
   1. The hostname part of the nameserver's name may not be numeric only: i.e. 123.example.com is invalid.
      (See: RFC1035 , RFC1123 , RFC1912 ).
   2. The name of the nameserver must not be be a bare domain name, it must have a hostname part (e.g. hostname.example.net).
5. Nameservers must be correctly registered with ISNIC.