[Ekiga-list] NAT problems debugging

[Jan Kasprzak]

	Hello,

recently I have tried to set up a SIP phone behind a NAT to call my
Ekiga on a public IP address (with ekiga.net as a SIP provider for both ends).
I have failed to do this because of NAT problems. I want to suggest
some things which would allow better debugging of these problems:

- move 500 at ekiga.net test number to a different IP address than ekiga.net.
	Rationale: for some broken NATs, the call to 500 at ekiga.net works
	exactly because it communicates with the same IP address over
	both SIP and RTP. But calls to any other host fail (and because
	in my case the two ends were 200km apart, I have found about
	the problem only after returning home with no way to debug the
	remote end for next three weeks or so). It would be nice if 
	the call to 500 at ekiga.net can fail as well instead of giving
	a false positive report. The problem would then be easier to detect.

- look at the IP address and port of the incoming RTP stream.
	Rationale: my problem was that the remote SIP phone did not
	detect its public port number correctly, so the incoming RTP
	stream was comming from a different port than the one announced
	during the SIP call setup. So I could hear the remote side
	(ekiga uses the incoming RTP data no matter what IP address and port
	they are coming from) but they could not hear me, because their real
	port number was different from what their SIP phone guessed using
	STUN.

	Maybe ekiga can look at the port number of the incoming
	RTP traffic, and if this does not match the expected one,
	display a warning dialog saying that the remote side would probably
	not be able to hear us. Or even start sending further outgoing
	RTP data to this port instead.

	I know, the proper solution is "use a public IP address",
which is what I will probably do (the remote ISP requires an additional
fee for this, though).

	Thanks,

-Yenya

-- 
| Jan "Yenya" Kasprzak  <kas at {fi.muni.cz - work | yenya.net - private}> |
| GPG: ID 1024/D3498839      Fingerprint 0D99A7FB206605D7 8B35FCDE05B18A5E |
| http://www.fi.muni.cz/~kas/    Journal: http://www.fi.muni.cz/~kas/blog/ |
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