No answer from internal telephony server accessed via NAT
we have a new IP telephone system, and there is a mobile phone app to connect our dedicated public IP using ports 9101 & 16203.
So we route all external traffic via NAT from our public IP to the internal telephone server. In our logs, we can see, that the traffic is being routed to internal server, but it seems that the answers back to mobile device won't be processed.
If we use the app in our LAN, everything works fine.