Hi there, I have a FS installation that is on a private network, with a SIP proxy in front of it that has an assigned public IP. I would like to be able to make calls from a public network to this FS installation, but I am not able to fully establish SIP and RTP sessions. I have been playing around with the NAT features of FS without any luck. In this scenario, do you think it would be necessary for the SIP proxy to handle the NAT traversal to ensure that the SIP responses reach the SIP endpoint? For RTP, would the proxy need to modify the SDP response that FS creates, so that it includes the external IP address necessary to establish the session? What I am getting at is whether the proxy needs to be not a proxy at all, but more like some kind of SBC, that also has RTP proxy capabilities. It would be necessary to keep this proxy/SBC in the signal path for both sessions. Any guidance on this scenario would be appreciated. Thanks, Adam