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 moves RFC3627 (Use of /127 Prefix Length Between Routers Considered Harmful) to historic as it has already been superseded by standard track document RFC6164 (Using 127-Bit IPv6 Prefixes on Inter-Router Links). The security considerations section says there are no new security considerations, and I think thisi is accurate. I have no comments for this document. -- kivinen at iki.fi