Good morning all Again I am having problems with my 3CX PBX system being registered in my voip provider. The error code I can see in the Server Status is: [CM506004]: STUN request to STUN server 18.104.22.168 has timed out; used Transport: 192.168.2.10:5060 [CM506004]: STUN request to STUN server 22.214.171.124 has timed out; used Transport: 192.168.2.10:5060 As you can see I have two different Stun servers to register the internal IP address of the 3CX PBX. Then if I run the Firewall test I get this error messages: Parameters Stun Server to test stunserver.org Stun Port to test 3478 Port Range to be tested 9000-9015 and the result I get for each of the ports 9000-9015 is : I have the PBX installed in a Windows 2003 Sever behind a router which is conected via cable to my Internet provider. Also I have checked with tracert and 126.96.36.199 is the external IP address I have now assigned by my Internet provider. The firewall in the Windows 2003 Server is turned off, and the router has these ports opened and redirected to the Windows 2003 Server. 3478 5060 9000-9015 Is there any other port I must have open? What I dont understand is that if I have the Stun server port 3478 openend and the ports for external calls 9000 to 9015 also opened, why the stun server is trying to "enter" using another ports like 16977??? 1 9000 Error (4) The STUN server returned an ip which is not accessible from outside. addrFromSTUN = 188.8.131.52:16977 Is there any place that specify which ports I should have open and redirected to the PBX server???... what I wont like is to have the router with all the ports open Another thing I have tried is to set the option "Registration Settings -- Which IP to use in 'Contact' field for registration:" to with the value : Specified IP: 184.108.40.206:5060, instead of having "External (STUN resolved)" With this I can register... but can not get any call... I mean I get the ring, but when I pick up, the call is disconected and does not get any sound. any help on how to set the right ports and stun configuration.??.. anyone can pass me his stun configuration and explain me how to set the ports??? thanks a lot in advance guys!!.