Hi, OPS-DIR, Authors,   I have reviewed this document as part of the Operational directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written with the intent of improving the operational aspects of the IETF drafts. Comments that are not addressed in last call may be included in AD reviews during the IESG review. Document editors and WG chairs should treat these comments just like any other last call comments.   This Standards Track document updates clearly the meaning and rules when a DNS resolver receives a response with response code of NXDOMAIN. It updates RFC 1034, 2308. This document is well written. I don't see any major issues from the operations and management perspective. It is ready to be published. There are one of minor comments from me:   Section 11.3 lists two URIs, which is rarely see in RFCs. I am sure the first URI should be removed by RFC editor, according to author ’ s note. But the second one seems meaning something in the real use. I guess it should be either reorganized as an informational reference or removed.   Best regards,   Sheng