Subject: [SIP] Via discrepancy in latest 2543bis draft.

From: "Fairlie-Cuninghame, Robert" <[email-masked]>
Date: Mon, 5 Jun 2000 03:56:25 -0700

Hi,

I believe that the first point in "Appendix G: Changes to be made" is
invalid and should be removed. Section 6.45.3 and 6.45.4 [Handling of Via's
in requests] are in contradiction to this statement:

* Bug: UDP spec not clear on whether responses sent to source port or port
in Via. Should use port in Via. 

I am guessing that this is merely an oversight as Section 10.2.1 had a
similar statement which was changed in the last draft version to agree with
Section 6.45.3 & 4.

Robert.

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From: "Fairlie-Cuninghame, Robert" <[email-masked]>
Date: Mon, 5 Jun 2000 04:51:10 -0700

Wait up ... quick back pedal ... now I'm not so sure. As written in Section
6.45.4 it does suggest that you would use the source port over the Via port
(as the "sent-by" includes the port part) but is this the best thing to do ?
We know this Via scheme won't work for a NAPT (without a SIP proxy sitting
on the firewall as well) so perhaps we should be using the port in the Via.
This at least allows SIP user-agent spawning to function normally across a
NAT.

Anyway, there is definitely a need for clarification here.

Cheers,

Robert.