Hi, I am new to Kamailio and coming a bit from the Asterisk side. Currently I'm using the Amazon EC2 Infrastructure and set up an Kamailio with standard configuration. EC2 uses Destination NAT on their side. Thus I enabled WITH_NAT and WITH_NATSIPPING. I'm using the rtpproxy from master branch of https://github.com/miconda/rtpproxy. Besides those two parameters I also changed the listen parameter in the Kamailio config: listen=udp:10.0.0.221:5060 advertise 52.59.XXX.XXX:5060 My rtpproxy is running with following parameters: ./rtpproxy -A 52.59.XXX.XXX -F -l 10.0.0.221 -m 20000 -M 30000 -s udp:*:7722 -d INFO When I use two Softclients (Zoiper) on different Networks (with Source NAT on the Firewall) the Softclient tries to transmit the RTP Packets to the Public IP of the other Network. But the Client obviously thus doesn't get the RTP Packets. Is there an easy and documented way to solve that issue? If I understood it correctly Kamailio together with rtpproxy should be able to receive the RTP Packets and forward them to the other client. So it should signal the IP of the Kamailio to send the RTP packets to. Or am I on the complete wrong way? Regards, Benjamin