[Freeswitch-users] Problem with NAT

A very simple (maybe) question. I have freeswitch installed behind a firewall with needs ports open I have users internal (connected to local lan address) and users external (connected to my public internet IP address) All users are configured in the directory/default. When I call from a lan user a external user all work fine When I call from a external user a lan user the call drop after 30-32 seconds When I call from a external user other external user the call drop after 30-32 seconds When I call from a lan user other lan user all work fine I thing is a NAT problem but I don't know how solve it Regards - Andrea -