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 is a good document, and I have no significant issues with it. It's ready to go. I have only one minor comment, in the Security Considerations section: At the time of writing the vast majority of TLD authority servers and all of the root name servers support TCP and the author knows of no evidence to suggest that TCP-based DoS attacks against existing DNS infrastructure are commonplace. Since this is a working group document, not an individual or independent submission, I'd rather see "and the dnsext working group knows of no evidence", to stress that the fact was reviewed by the working group, and the statement has working group consensus. This is, of course, assuming that that's truly the case -- if it is not, then I do have an issue with that. -- Barry Leiba