Re: LLMNR Issue 58: DNS server usage of LLMNR

[Masataka Ohta <mohta@necom830.hpcl.titech.ac.jp>]

Bernard Aboba;

> One possible scenario would be where only some of the local IPv6 hosts are
> LLMNR capable and support DHCPv6lite.  Hosts that do not support DHCPv6lite
> might not be able to register their AAAA and corresponding PTR RRs with
> the DNS server authoritative for the names of local hosts (e.g. the router).
> Other hosts might support DHCPv6 lite, but might not be able to act as
> either an LLMNR sender or responder.
>
> In such a situation, an LLMNR-incapable host might send a DNS query for a
> AAAA or PTR RR of a host that didn't support DHCPv6lite, but could act as
> an LLMNR responder.  The DNS server would respond with RCODE=3, at which
> point the querier would have no recourse, since it doesn't support LLMNR.
> However, if the DNS server sent an LLMNR query for the name, it would get
> an answer which it could relay back to the querier.

Your hidden assumption is that all the related hosts are on a
single link or that all the hosts on a link belong to a local
forward domain served by nameservers, all of which is on the
link.

Otherwise, we have no idea on where to ask the forward query,
even if you say LLMNR.

Given so much confusion on usefulness of LLMNR and an attempt
to mandate LLMNR for IP over BT, I'd like to suggest to
abandone LLMNR entirely, or, at least, add explicite explanation
stating its narrow scope, such as:

	LLMNR is expected to be useful for nodes on an isolated
	IP network with a single link, but not beyond that. LLMNR 
	MUST NOT be used by nodes connected to the Internet nor
	an isolated IP network with multiple links.

							Masataka Ohta



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