Jiri Kuthan wrote:
At 08:12 04/03/2008, girish kumar wrote:
Hi,
I have 2 SIP based softphones (Xlite) registered on IPtel.org SIP service and testing the calls among them. These 2 softphones are behind different NAT and IPtel.org SIP proxy is replacing the SDP connection details in Call setup message (Invite and 200 OK) with RTPproxy IP/ports. Hence, RTPproxy is relaying the Voice media stream among them during the call.
Although, both the softphones are behind different NAT address but these are not Symmetric NATs and hence RTP can directly flow between these softphone using STUN discovery.
That's what I'm not sure about. If they were using STUN, iptelorg:5060 should not have detected them as natted. Any insight in this?
Is it possible to disable the RTP proxy behaviour of IPtel.org SER server for these 2 softphones through some configuration changes or any special header parameter in call setup message?
In User Management web interface of IPtel.org, there is a option to specify the connectivity realm for a user account under My Account -> Other tab.
The description of this field is "connectivity realm - behind the same NAT or possibility to communicate directly". I believe this field is playing some part in NAT transversal mechanism of Iptel.org SER implementation.
I think too that was thought so, but I think it is unused at the moment.
Yes, it was meant to work this way. If both phones are configured to be in the same connectivity realm then the server assumes that they can reach each other directly and it does not enforce the RTP proxy, no matter what does the NAT detection algorithm says.
Unfortunately this option is not currently used in the configuration of the iptel.org SIP server.
I will try to put it back as time permits (because I need it myself for my phones).
Hope that helps, Jan.