I am using the features-callfwd.cfg script with mediaproxy in a testing server. I can make call directly from phone to phone and forward call. However, it is failed to forward call on no answer and forward call on busy. In my testing server, it only has a network interface. I wonder if it is the cause of the problem. Does it need to have 2 network interfaces (one for external and one for internal) for those forward features work?