Possible that I'm being dumb here but trying to set up a trunk to the inside interface and IP of our SBC from thirdlane on the local network. Thirdlane tries to use it's outside/public address to connect when I make an outbound call. This obviously fails. The local interface of Thirdlane and inside of SBC are on the same network (192.168.20.x/24) and can see each other.
An inbound call ITSP - SBC - Thirdlane routes ok and rings through although we've one way audio. (possible this is part of the same problem)
Is it possible or how can I can get the trunk to use the inside/local interface to route to SBC?