We have an old 32-bit C++ service app that opens and listens on several TCP ports.
The app needs to be moved to a contemporary server, and to test it, we are using Win Server 2019 running on an Oracle VirtualBox installation, which is in turn hosted on a Win 10 machine. Win Server 2019 via the Oracle VM is configured to use a "Bridged Connection" and is assigned an IP address. All of the IP-related connectivity works except the open/listen aspects.
The app communicates correctly with other TCP-based resources (it connects to both MySQL and SqlExpress). It seemingly opens the TCP ports that it needs to open and listen on, but doing a "netstat -nao" shows that nothing is listening on the specified ports (6000, 7000, etc.), so the open/listen functionality is not working.
There are several possible reasons why the app is not working correctly: