Last Call Review of draft-ietf-6man-prefixlen-p2p-
review-ietf-6man-prefixlen-p2p-secdir-lc-austein-2011-02-01-00

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 draft discusses several reasons why the recommendations against
using 127-bit prefixes on inter-router IPv6 point-to-point links in
the current RFCs are not merely specious but actively harmful, and
details several attack scenarios in which 127-bit prefixes on
inter-router point-to-point links are a better defense than anything
that can be done with 64-bit prefixes.  The draft concludes by
requiring (if this draft is adopted) router support for 127-bit
prefixes and makes some recommendations on how to avoid having use of
127-bit prefixes cause problems with other IPv6 implementations.

I have no security concerns regarding this document.  Should have done
this years ago, and the authors of this draft deserve our thanks for
their perseverance.