Subject: [Sip] question on draft-ietf-sip-nat-00.txt

From: [email-masked]
Date: Tue, 4 Sep 2001 20:45:05 -0400

Hi,

Based on the response routing procedures specified in Section 10.46.5, page
60 of bis-04, the UAS should use the "maddr" value, if present in Via
header, to send a SIP response over UDP. If the "maddr" is not present, the
UAS should then use the source IP address.

The draft-ietf-sip-nat-00.txt doesn't mention the "maddr" address. If the
client inserts a "rport" parameter in Via header as well as a "maddr"
parameter, should the server ignore the maddr parameter and always send the
response to the source IP address and port?

Thanks,
YoungSun

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---

From: Jonathan Rosenberg <[email-masked]>
Date: Wed, 5 Sep 2001 02:15:43 -0400

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]]
> Sent: Tuesday, September 04, 2001 8:45 PM
> To: [email-masked]
> Subject: [Sip] question on draft-ietf-sip-nat-00.txt
> 
> 
> 
> Hi,
> 

Right. maddr in the via is for multicast.

> response to the source IP address and port?

Good question. Assuming multicast actually works through nat (highly
unlikely), you would want the response to be sent via multicast, and
therefore it should use the maddr address and the port in sent-by. The
source port is not what you want at all for multicast.

I'll add wording to describe that.

-Jonathan R.
---
Jonathan D. Rosenberg, Ph.D.                72 Eagle Rock Ave.
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