Hi, I'm trying a way to make a p2p link application with NAT traversal without SIP server, and I tested the "icedemo" in the pjsip-app sample. It successfully communicated with another peer behind single NAT with STUN(-s numb.viagenie.ca), but failed if behind 2-layered NAT. and then I tried TURN(-t numb.viagenie.ca), but it always negotiation fails. command is as following, with pjsip2.0: ./icedemo -s numb.viagenie.ca -t numb.viagenie.ca -u xxxxx at gmail.com -p xxxxxxx Could anyone tell me what's wrong here?? Or could anyone tell me how you successfully tested this sample. Sincerely, Smith