it is installed on a linux server which has a private ip address (192.168.0.x).
Then there is a Firewall NATting a public ip towards it.
When DE sends commands to remote devices to retrieve configuration or do other commands, it sends the internal address instead of the public one, for instance:
of course this doesn't work because the remote device cannot reach 192.168.0.x but it needs to know the public ip that nats to this address.
I see no option to inform DE that it's running behind a nat and that it should send a defined public address to devices instead of the one gathered from the local machine configuration.