I have a strange case that I'm not entirely sure how to approach. I am in the process of moving our offices to a new location. I have decent DSL setup at the new location, but my SIP provider, Cbeyond is about a month out on moving. The problem comes from the fact Cbeyond's servers aren't accessible through the internet and only resolve in their 'internal' network, thus the PBX has to be connected to their endpoint device. I currently have 4 extensions at the new site connecting to the old site through the SIP proxy, it works well enough but unfortunately I have the PBX installed on a server that needs to come with us to the new site. I am looking for a way to keep the PBX at the new site but use some sort of tunnel to a proxy at the old site purely to route incoming and outgoing calls through the Cbeyond SIP trunk. I think a bridge is the correct approach to this, I am unsure exactly how I need to setup the master/slave and what rules are needed to route calls. My current routing logic is an explicit route for 911, and beyond that greater than 3 digits is sent to the provider on 10000.