Every .dk domain whose MX record points to 7EWLEJEGMBWMY3KKTNMKB6V4UQ7EMHUJEOCEKRDDKBXRT4BZ7KHQ.MX-VERIFICATION.google.com. Mail-server reverse lookups show which organisations share a mail provider and how widely a hosted mail platform is used. Data comes from our own scanners, which re-resolve every .dk domain in the zone roughly once a week.