Dear all,

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 an extension to  STUN for determining the
characteristics of connections, useful in situations where hosts have
multiple interfaces. It does this by enabling
clients to send multiple requests and receive counts of how many
responses were transmitted.

This document was Ready with Nits. Some values need to be assigned by
IANA. It reuses existing security mechanisms from STUN, which do in
fact protect the integrity of messages
properly. I am worried about interoperability questions, but these
come from those earlier
RFCs, and so are outside the scope of this review.

Sincerely,
Watson