Remote Users

Hi

i have just setup a remote user over in poland i am using the latest free pbx software FreePBX 2.5.1.5

The problem i am getting is that you can see the phone registered but when you dial the extn you get silence after 1 ring .

ok so i have connected onto the customers switch and registered an exten, remotley from my office I can ring the poland extention and also talk to them but when they try to call me back my phone rings but get silence.

i have advised that it could be a router problem there end but they say that all ports are open.

I can not seem to get my head around that when i call Poland i can talk to them with no problem remotley at my office, but when you try to call Poland from the customers site ( Where the Pbx is Located) you get silence.

Can any one advise me.