Hi, I have SER connected to two non-routable networks: My machine has two IP addresses: 193.136.2.2 and 10.0.0.135 And I want the clients in these two networks o speak each other. I started RTPproxy with "-l 10.0.0.135/193.136.2.2" option. And I tried the configuration example that´s in: /ser-0.9.0/modules/nathelper/examples/alg.cfg Thats my network configuration: client A |-------| client B 193.136.7.13- ------------- 193.136.2.2--| SER |-- 10.0.0.135---------10.0.11.243 public IP client SERs public IP |-------| SERs private IP private IP client But even with RTPproxy and NAThelper it isnt working, because when I call from client A to client B, this happens: INVITE: 193.136.7.13 --> 193.136.2.2 (thats OK) INVITE: 193.136.2.2 --> 10.0.11.243 (ERROR:this cant happen because the networks are non routable) It should be 10.0.0.135 to contact client B. From client B to client A the same happens: INVITE: 10.0.11.243 --> 10.0.0.135 INVITE: 10.0.0.135 --> 193.136.7.13 ERROR: non routable networks Can someone tell me what changes must be done to implement the proxying of the calls between the two SER IP addresses? Thanks Joao Pereira www.fccn.pt