On Tue, May 21, 2013 at 10:26:39AM +1000, Mark Andrews <marka@xxxxxxx> wrote a message of 52 lines which said: > I'm not sure what the solution should be but regular audits of > delegated nameservers by infrastructure operator and removal of > delegations after a grace period Let's not reinvent the wheel: I suggest to first study the experience of the TLD which did exactly that. .fr had mandatory technical tests of the name servers almost from its inception, until december 2012. The tool used for the tests was Zonecheck <http://www.zonecheck.fr/> Although these tests certainly contributed to the good technical quality of the name servers, they were removed both for commercial reasons (a registry has to make money to pay its employees) and because it was easier to have the same rules for ccTLDs and gTLDs (and ICANN forbids these technical tests in gTLDs).