I have a question about the use of STUN, as a way of discovering IP
address(es), in draft-ietf-geopriv-res-gw-lis-discovery.
Section 4.1 refers to STUN by way of RFC 5389, but reading both the present
draft and 5389 leaves one critical item unspecified:
o What domain name is to be used, in the SRV query ("_stun._udp.domain" or
"_stuns._tcp.domain" -- what value of "domain" is to be used in the query)?
Without that being specified, implementers/users have nothing specific to try,
and without that, I do not see how STUN could be used at all.
Similarly, recommending that STUN be provisioned (section 4.6) leaves the
question of "under which domain", unanswered and ambiguous.
Section 4.4 suggests that STUN servers be able to see the public IP used, but
again, how should the STUN server be found?
This may have been an oversight by the authors, and they may already have
envisioned answers to these questions.
Even section 7 (IAB considerations) is IMHO incomplete without the necessary
"domain" specification for STUN usage.
I think resolving this issue is critical for the document to serve its stated
purpose.
(Is there perhaps a companion STUN RFC that does discuss this? If so, adding
that as a normative reference may suffice, and linking to that in sections 4.1,
4.4, 4.6, and 8.
Modulo this oversight, I believe this is a well-written document and fills in
an important gap in LIS deployment and use.
Brian Dickson
