Every .dk domain whose web server address has the reverse-DNS (PTR) name 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.3.7.e.d.7.0.7.1.0.b.8.0.1.0.0.2.ip6.arpa, which usually identifies one physical or virtual hosting server. Data comes from our own scanners, which re-resolve every .dk domain in the zone roughly once a week.