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 describes a way to extend the IPv4 address space by reclaiming some of the TCP/UDP port bits for use as address bits. The document is well written, and the security considerations seem complete. I see no security issues with this document. --Scott