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 a simple definition of a PKIX key usage for SIP proxies. It is, in essence, no different than a PKIX key usage for any other server, and thus doesn't introduce any interesting security issues.