I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments. This document is progressing RFC 4931 from Draft Standard to [full] Standard. That's an entirely appropriate thing to do, and I see no issues with this document. I also note, as requested in the Last Call notice, that I think the downreference to RFC 952 is appropriate. Two nits that I noticed, both in Section 1.1: OLD Name server hosts for domain delegation can be specified as either references to existing host objects or as domain attributes that describe a host machine. NEW Name server hosts for domain delegation can be specified either as references to existing host objects or as domain attributes that describe a host machine. OLD - Zero or more OPTIONAL element that contain the IP addresses to be associated with the host. Each element MAY NEW - Zero or more OPTIONAL elements that contain the IP addresses to be associated with the host. Each element MAY Barry -- Barry Leiba (barryleiba at computer.org) http://internetmessagingtechnology.org/