I am so sick of one-way audio issues! It seems that nothing is totally reliable if there is any NAT anywhere. Can the original design of SIP/RTP really be this horrible? OK, enough general venting. The tunnel is the answer, the way the audio should have been routed in the first place. Congratulations to 3CX for bringing forward a solution that is simple to use and totally reliable!!! Any word on when the iPad (1.1.4) softphone will have this feature? It is unusable as it is. I will post a separate note on the specific configuration (only one of SO MANY that have caused me pain pre-tunnel).