We are trying to setup remote extension on 3CX (Unidata WPU-770), phones work fine in the office but not remotely. To try and test connection I have setup the 3CXPhone on my pc (Windows7) and found following; 3CX phone can connect using tunnel. 3CX phone can connect using TCP 3CX phone can NOT connect using UDP Checked firewall and port open for UDP & TCP, done the Firewall test and everything passes. Any ideas on why UDP would fail and how I can find out if Unidata phone uses UDP or TCP? Gary.