[OpenSER-Users] rtpproxy seems to be idle

[Klaus Darilion]

Kovács Zoltán schrieb:
> Hi,
> 
> my plan is to give the possibility for multiple VoIP users within the 
> same LAN to call each other using OpenSER as the SIP server. I found 
> that if there is a NATed LAN, two different VoIP users inside the NATed 
> LAN cannot talk to each other properly, because IP parts of the RTP 
> packets are of the form of the local network and it is not acceptable by 
> the VoIP software which is prepared for the IP of the router instead. (I 
> hope I understand clearly what is going on here.)
> 
...

> 
> Could somebody please help me why there is no media stream between 
> OpenSER and rtpproxy?


Between Openser and rtpproxy is no media traffic, just the proprietary 
rtpproxy protocol which is used by nathelper module to control the rtpproxy.

Nevertheless it looked like there was no media stream between the SIP 
client and the rtpproxy.



+-------+            +-------+
|       |<---SIP---->|SIP    |
|       |            |Proxy  |
|       |            |       |
|       |            +-------+
| SIP   |               ^
| Client|               | proprietary RTPPROXY protocol
|       |               v
|       |            +-------+
|       |            |RTP    |
|       |<---RTP---->|Proxy  |
+-------+            +-------+


1. Use ngrep to inspect the SIP message:
  - look if the IP address in the c line in the SDP is replaced with the 
rtpproxy's IP address and the port number is replaced with the port 
number allocated by rtpproxy

2. use tcpdump/wireshark/.... to verify if there are RTP packets sent to 
your server. MAybe there is a firewall which blocks RTP packets.

regards
klaus