Subject: Review of draft-ietf-dprive-dtls-and-tls-profiles-08

From: Colin Perkins <[email-masked]>
Date: Fri, 03 Mar 2017 09:37:12 -0800

Reviewer: Colin Perkins
Review result: Ready with Nits

I've reviewed this document as part of TSV-ART's ongoing effort to
review key IETF documents. These comments were written primarily for
the transport area directors, but are copied to the document's authors
for their information and to allow them to address any issues raised.
When done at the time of IETF Last Call, the authors should consider
this review together with any other last-call comments they receive.
Please always CC [email-masked] if you reply to or forward this
review.

Summary: Ready with nits

The draft describe authentication mechanisms for DNS servers accessed
via TLS and DTLS, and defines profiles for DNS clients and servers
implementing DNS-over-TLS and DTLS. There seems little of transport
concern here, since the draft refers to RFC 7858 and
draft-ietf-dprive-dnsodtls to specify DNS over TLS and DTLS, and
doesn't define such mechanisms itself, Similarly, the (D)TLS profile
is a security profile, rather than transport-related changes.

I just had a couple of nits:

- The short title at the top of each page is “(D)TLS Authentication”.
If there’s space, it'd be clearer if this was “(D)TLS Authentication
for DNS”, or similar, to avoid confusion about what is being
authenticated. 

- Section 9 mandates implementation of TLS session resumption without
server-side state [RFC5077], TLS False Start, and the TLS Cached
Information Extension. I can’t comment on the security implications,
if any, but these extensions seem appropriate for reducing transport
overheads. However, the recommendations in this draft seem
inconsistent with those in RFC 7858 (e.g., RFC 7858 says "DNS servers
SHOULD enable fast TLS session resumption [RFC5077], and this SHOULD
be used when reestablishing connections" but this draft is "MUST
implement"). It would help to align these, or mark this draft as
updating the RFC. 

Colin