ICANN has published a revised procedure, entitled "Technical requirements for authoritative name servers", on the IANA website.
When a domain operator within an IANA-managed zone (such as a top-level domain operator) wishes to change their authoritative name server delegation details, ICANN performs technical checks against the proposed servers. These tests are designed to check minimal conformance with technical standards to ensure the domain will function correctly.
The previous technical conformance criteria available on the IANA website were published in 2001, and did not comprehensively reflect current practice. Recognising the need for better documentation, staff also felt that the intent of the checks could be better fulfilled by implementing improved evaluation techniques.
ICANN published the current set of tests performed and solicited public feedback on those tests. Useful contributions were received from many parties, both through the public comment period, and through subsequent discussions at operator forums. This feedback, particularly from the top-level domain operator community, formed the basis of the revised requirements.
In the procedures, the technical checks performed are advisory. If the domain operator does not meet all the criteria, if they can show Internet stability is not harmed then the technical changes can still be accepted.
Technical requirements for authoritative name servers http://www.iana.org/procedures/nameserver-requirements.html
Call for public comments on technical check procedure http://www.icann.org/en/announcements/announcement-18aug06.htm
Comments received during call for public comments http://forum.icann.org/lists/techcheck-comments/