Hi,

I’m using SER with nathelper and rtpproxy as a proxy to guard a PSTN gateway ( calls can only be generated by SIP client and terminated to PSTN, no SIP to SIP or PSTN to SIP calls allowed, REGISTER is not needed ).

PSTN gateway and SER eth0 have pubblic internet IP address ( SER eth0 x.x.x.246,  PSTN gateway with two interfaces, x.x.x.243 for SIP and x.x.x.244 for RTP ), SER is setted to force rtpproxy for every call and rtpproxy is started in standard mode: this is running fine, every client from internet ( behind a NAT box or not ) is able to place calls.

Now the problem is that I need to collect SIP traffic from another non routable network to the PSTN gateway ( es. 10.0.0.0 )  

I have connected SER interface eth1 to this network ( ip 10.0.0.1 ) and I am trying to connect to the PSTN from a client in the network 10.0.0.0: SIP signaling seems to be ok, but I’m unable to setup RTP stream.

With this configuration it appears that RTPproxy try to connect to PSTN gateway on x.x.x.243 and not x.x.x.244.

I have tryied to set RTP proxy in bridge mode ( rtpproxy -l x.x.x.246/10.0.0.1 ) without succes, but documentation is not very clear about this case (I think it has been designed for client to client, not client to PSTNgateway ).

…..

if (dst_ip == x.x.x.246) {         #!! Internet IP address

                             force_rtp_proxy("FI");

                             t_on_reply("1");

          } else if (dst_ip == 10.0.0.1) {  #!! Private IP address

                             force_rtp_proxy("FE");

                             t_on_reply("1");

          };

…..

Now the question is: what is the correct design to implement this ?

RTPproxy in standard mode ?

RTPproxy in bridge mode ? ( how ??? )

Mediaproxy ?

Any help would be appreciated, many thanks in advance.

Fabio