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 ADs. Document editors and WG chairs should treat these comments just like any other last call comments. This document defines the new "state" clause for trace header fields that are used in SMTP. The use of these clauses are optional, and are used to indicate that a message is entering processing queues such as for moderation or quarantine. The Security Considerations section is quite short; basically, the section says "this might leak some local policy information" and "there are more security considerations for SMTP trace headers in the current SMTP spec". Because the new clause is completely optional, this adequately describes the relevant security issues. --Paul Hoffman