Greetings, I'm new to OpenSBC and relatively new to SIP as well. I understand that OpenSBC can be used to allow a IP PBX to traverse NAT for purposes such as connecting to an ITSP. I've got a test OpenSBC box which currently sits directly behind my PIX firewall with a static public-private NAT translation. My attempts to follow the quickstart instructions and establish a connection with the public echo server have failed. I've enabled tcpdump on the OpenSBC box and can see SIP INVITES going out to fwd.pulver.com, however, no responses are received. I suspect that this has to be due to the Contact URI which still references the private IP address on captured outbound packets to fwd.pulver.com. I've set the "Static RTP Media Address" with my public IP address but this only seems to apply to RTP. I'm probably missing something obvious. Any help would be greatly appreciated! Thanks