Hi Brian,
> On Mar 7, 2016, at 5:48 PM, Brian E Carpenter <[email protected]> > wrote: > > I am the assigned Gen-ART reviewer for this draft. The General Area > Review Team (Gen-ART) reviews all IETF documents being processed > by the IESG for the IETF Chair. Please treat these comments just > like any other last call comments. > > For more information, please see the FAQ at > <http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>. > > Document: draft-ietf-dprive-dns-over-tls-07.txt > Reviewer: Brian Carpenter > Review Date: 2016-03-08 > IETF LC End Date: 2016-03-15 > IESG Telechat date: 2016-03-17 > > Summary: Almost ready > -------- > > Minor Issues: > ------------- > > "3.1. Session Initiation > > A DNS server that supports DNS-over-TLS MUST listen for and accept > TCP connections on port 853. By mutual agreement with its clients, > the server MAY, instead, use a port other than 853 for DNS-over-TLS. > > DNS clients desiring privacy from DNS-over-TLS from a particular > server MUST establish a TCP connection to port 853 on the server. By > mutual agreement with its server, the client MAY, instead, use a port > other than port 853 for DNS-over-TLS." > > Well, that makes my head hurt. I think the only way to relieve the pain > is if both of those MUSTs are replaced by "MUST by default". However, > that means that both clients and servers need a configuration option > to use a different port, and I think that needs to be stated too. "Must by default" sounds fine with me. I've made that change and added a sentence about configuration options. New text: A DNS server that supports DNS-over-TLS MUST by default listen for and accept TCP connections on port 853. By mutual agreement with its clients, the server MAY, instead, use a port other than 853 for DNS- over-TLS. In order to use a port other than 853, both clients and servers would need a configuration option in their software. DNS clients desiring privacy from DNS-over-TLS from a particular server MUST by default establish a TCP connection to port 853 on the > "4.1. Opportunistic Privacy Profile > ... > With opportunistic privacy, a client might learn of a TLS-enabled > recursive DNS resolver from an untrusted source (such as DHCP while > roaming), it might or might not validate the resolver." > > This seems rather underspecified to me. How would a TLS-enabled > resolver be identified in DHCP? How would it be described in > an IPv6 RA (RFC6106)? Such DHCP features would need to be defined. > I would have thought that the natural thing would have been to > simply try TLS on port 853, and be happy if it worked. How does this strike you then? With opportunistic privacy, a client might simply try port 853 on a normally configured recursive DNS resolver, or it might learn of a TLS-enabled recursive DNS resolver from an untrusted source (such as with a yet-to-be-defined DHCP extension or ICMPv6 type). The client might or might not validate the resolver. These choices maximize availability and performance, but they leave the client vulnerable to on-path attacks that remove privacy. > > "9. Security Considerations" > > I hoped to find a comment on interaction between DNS/TLS and DNSSEC, > even if the comment is only that there is no issue. We mention this in the introduction, but I think its fine to repeat it in Security Considerations: Note, DNS Security Extensions (DNSSEC) [RFC4033] provide _response integrity_ by defining mechanisms to cryptographically sign zones, allowing end-users (or their first-hop resolver) to verify replies are correct. By intention, DNSSEC does not protect request and response privacy. DW _______________________________________________ Gen-art mailing list [email protected] https://www.ietf.org/mailman/listinfo/gen-art
